Wednesday, December 22, 2010

Compelling Planetary Science Missions: Mars Geophysical Network and Mars Polar Climate Missions

This continues a series of posts inspired by a similar set of posts at Future Planetary Exploration blog selecting the 5 most compelling missions from the Planetary Science Decadal Survey list.  This follows 3 reviews of potential Mars missions.  Here I make my personal selection from that list.

After some consideration, I decided not to include the MAX-C rover in my list of most compelling Planetary Science missions from the Decadal Survey list.  The mission science is compelling, the raw idea of a rover exploring and selecting Martian samples for return to the Earth is right, the mission is in a reasonably advanced state of development, and it has international cooperation and multi-mission implications.  Thus, it is not to be set aside lightly, and as you'll eventually see I'm not setting it aside lightly.  However, the estimated mission cost is just too much for me, and I'm worried about the new rover delivery mechanism.  Demonstration of the Sky Crane at Mars, combined with validation that a Network Pathfinder could be added to the mission with minimal risk and cost, might be enough to squeeze MAX-C into my top 5 most compelling missions, but those things haven't happened yet.

It's all about opportunity cost and risk.

This is easy for me to do because I haven't been waiting for those Mars samples for half a career.  I suspect that if I had been, I'd have made a different choice.

Having dealt with MAX-C, the question now becomes which Mars mission will I choose for my "most compelling" list - Mars Geophysical Network or Mars Polar Climate Mission?

The answer: All 3 of them.  Or all 4 of them.

I think I'd better explain.

In the last couple posts, I described a number of potential Mars Polar Climate and Mars Geophysical Network mission options.  Some key options include:

2 Mars Geophysical Network powered landers - $1,015M (New Frontiers)
1 Mars Geophysical Network powered lander - $720M (Discovery)
Mars Polar Climate Orbiter - Climate and Weather - $613M (Discovery)
Mars Polar Climate Orbiter - Energy Balance and Composition - $629M (Discovery)
Mars Polar Climate Orbiter - Polar Science - $866M (New Frontiers)
Mars Phoenix Class Lander - Sightseer - $751M (Discovery)
Mars Phoenix Class Lander - Subsurface Sampler - $860M (New Frontiers)
MER Class Rover - $1,049 (New Frontiers)

My selection for the 3rd most compelling mission from the Decadal Survey list is a combined Mars Polar Climate mission consisting of an orbiter and a lander.  Thus 2 of the Mars Polar Climate options above would be selected.  These should be mutually supportive with remote sensing and ground truth in-situ observations of the same physical entities.  The orbiter can also help the lander through its telecommunications capability (which would be supplied by NASA to the mission as standard procedure for Mars orbiters).

I selected the Mars Polar Climate mission for a variety of reasons.  It addresses science questions about climate that are relevant to our situation on Earth.  Mars offers another extreme environment and history to compare to Earth, just as Venus does as explained in the Future Planetary Exploration blog's choice of a Venus Climate mission as the second compelling mission.  In addition, the mission has potential as an astronaut scout sort of operation (i.e. a science substitute for a robotic precursor mission).  The missions could be a good fit for collaboration with any funding that may appear in NASA's Exploration Technology Demonstration or Robotic Precursor efforts.  With additional mass budgets, they offer plenty of opportunity for super-charging with instruments from non-NASA space agencies, too.  Of course the missions go after big Planetary Science questions about Mars, too.  The missions follow up on technology and science demonstrated and advanced in earlier Mars missions, so the risk of cost overruns, mission failure, or unimportant science is lower than it otherwise might be.  Also, assuming no cost overruns, the missions are affordable.  For example, if we select the "Climate and Weather" orbiter as a revival of the "Mars Scout" line, and also select the subsurface sampler as our New Frontiers mission (since these Decadal Survey selections are supposed to be for New Frontiers and Flagship missions), we are only (if I may use that word when talking about huge amounts) at $613M + $860M = $1,473M.

My selection for the 4th most compelling mission is the Mars Geophysical Network Mission.  Since the science value of this mission goes up considerably with 2 landers rather than 1 lander (as, for example, the seismometers will return much more valuable data with simultaneous, time-synchronized data collections at different locations than the mere location of 2 landers at 2 distinct geographical locations would suggest), I'll select the $1,015M New Frontiers powered landing option with 2 landers.  Still the 3 missions combined are $2,488M, which isn't much more than the estimated MAX-C cost.  Had I selected the single Geophysical Network lander delivered on a Falcon 9 rocket (i.e. the Discovery class version), the 3 missions would cost less than MAX-C.  Like the Mars Polar Climate missions, the Mars Geophysical Network Mission addresses fundamental Mars science, gives lots of opportunities for international collaboration and thus more capable missions, and presents interesting possibilities for collaboration with potential NASA Exploration Technology Demonstration and Robotic Precursor efforts.

I've picked particular variants from the selections above, but I think the basic idea would work with other choices.  For example, we could switch the polar deposit Subsurface Sampler to the Mars Polar Climate rover (exchanging instrument mass for mobility).  This might be justified on grounds of mission science return or keeping our ability to develop Mars rover missions.  We could switch back and forth between Discovery and New Frontiers levels as funding allows and external participation (or lack thereof) encourages.  Call it the Flexible Path at Mars.

Tuesday, December 21, 2010

Compelling Planetary Science Missions: Mars Background, Part 3 (Mars Polar Climate Mission)

This continues a series of posts inspired by a similar set of posts at Future Planetary Exploration blog selecting the 5 most compelling missions from the Planetary Science Decadal Survey list.  This is the 3rd of 3 reviews of potential Mars missions, building up to a selection from that list (and I've already revealed that Mars will not be skipped in my overall selection of 5 compelling missions).

The Mars Polar Climate Mission Concepts report doesn't focus on a single mission, but instead gives a broad overview of the types of missions that could study the Martian polar deposits to reveal information about the planet's climate.  Six potential missions, covering Discovery and New Frontiers classes, are investigated: 3 orbiters roughly similar to Mars Odyssey or Mars Reconnaissance Orbiter, 2 landers roughly similar to Mars Phoenix, and 1 MER-class rover.

Clearly the MAX-C rover is a more well-developed plan than these conceptual missions, but that may be balanced somewhat by the argument that these missions are simpler and use a great deal of heritage hardware.

These missions would all study the Martian climate through its polar layers, but they would do that in quite different ways.  Science questions include the age, energy budget, and mass of the polar deposits, volatile movement between the polar layers and other regions, historical Mars climate change as reflected in the polar layer records, and how the layers might be affected by influences like erosion, dust and carbon dioxide cycles, and liquid run-off.  Orbiters tend to be better at measuring large-scale processes like water and dust transport in and out of the polar regions.  Landers would be better at measuring composition of the layers, isotope ratios, and other characteristics that require sample handling or close observation.  Quite a few measurements could be made by either orbiters or landers.

Two Discovery class orbiter missions are described.  One mission selects instruments that emphasize current weather, climate, and polar change over the course of a season.  The other mission emphasizes current movement of water and dust into and out of the polar layers, comparing this information to polar layers that record the history of similar movements.  The single New Frontiers class orbiter addresses both of these areas.  The estimated FY15 costs with reserves for the orbiter missions are $613M, $629M, and $866M, respectively.

The body of 2 static landers described in the report would be similar to the Phoenix lander.  One Discovery class static lander is described.  This would land next to a polar layer region and observe the layers from below using a high resolution multispectral imager.  It would also include a meteorology instrument suite.  The New Frontiers class static lander would land on one of the polar layered deposits and sample the deposit using melting or drilling, laser, camera, microscopic imager, meteorological suite, and spectrometer.  Rough FY15 mission cost estimates with reserves are $751M and $860M, respectively.  Based on the power and mass capabilities of the Phoenix landing platform and the limits placed on the instrument suites by the expected Discovery and New Frontiers cost limits, considerable additional capabilities (drills, robotic arms, sensors, etc) could be added to the landers if funded by external sources.  For example, the mass of the strawman instrument suite for the Discovery mission is 11.3 kg, and the mass of the instrument suite for the New Frontiers mission is 31.2 kg, but the Phoenix platform allowed 65.0 kg.

The New Frontiers class rover, costed at $1,049M, would bring a rock corer like the one planned for the MAX-C rover, a mass spectrometer, imagers, and a meteorological package, all with heritage from other Mars rover missions.  The rover itself would be based closely on the MER rovers.  The mission would be expected to last at most 90 sols if based on solar power because of the encroachment of the polar cap and lack of sunlight near the pole as winter approaches.  The value of the rover is that it would be able to directly access multiple polar deposit layers.

The next post in this series will include my selection of the most compelling mission from among the MAX-C rover, Mars Geophysical Network, and Mar Polar Climate missions.

Monday, December 20, 2010

Compelling Planetary Science Missions: Mars Background, Part 2 (Mars Geophysical Network)

This continues a series of posts inspired by a similar set of posts at Future Planetary Exploration blog selecting the 5 most compelling missions from the Planetary Science Decadal Survey list.  This is the 2nd of 3 reviews of potential Mars missions, building up to a selection from that list (and I've already revealed that Mars will not be skipped in my selection of 5 compelling missions).

The Mars Geophysical Network Options Decadal Survey study presents a number of options beyond the Network Pathfinder described in the previous post to study the interior of Mars.  The science to be addressed by these mission options includes seismology, precision tracking to measure Mars rotation rate, precession, nutation, and polar motion, meteorology to determine atmospheric effects to the seismology instrumentation, subsurface heat flow analysis, and electromagnetic sounding.  Science goals including measuring the structure, composition, and size of the crust, mantle, and core, and measuring heat flow through the crust.  For simplicity, only the key seismology and (telecommunications-based) precision tracking capabilities are considered in cost comparisons, although there is ample room for more instrumentation in the landing mass allowances.  Because multiple simultaneous seismology measurements increase the value of these measurements considerably, from 1 to 3 distributed landers are considered in the options (hence the Geophysical Network).  Other variations beyond the number of landers include landing method (airbag or powered), mission "class" (New Frontiers, Discovery, or Mission of Opportunity hitching a ride), and method to get to Mars (shared vehicle, free flyer, or secondary payload)

Interestingly, the basic "Mission of Opportunity" scenario estimated costs ranged from $522M to $627M, far higher than the Sky Crane Network Pathfinder option described in the previous post.  New Frontiers class scenarios with 2-3 landers ranged from $1,015M to $1,347M; only the scenario with only 2 powered landers fit the New Frontiers cost limit.  For the Discovery mission class options which all had only 1 lander, only the Falcon 9 launch and powered landing approached (but, at $720M, still exceeded) the anticipated FY15 Discovery mission cost limit.  It is noted that for these missions with high heritage from systems already used on Mars (e.g.: Mars Phoenix, Mars Exploration Rovers, and Mars Pathfinder), the Decadal Survey's required development phase reserves (50%) might be more than is needed for these mission options with little technology to develop.  Also, costs were made based on all U.S. development, but it's expected that the main instrument, the seismometer, would be contributed by a European agency.  It's possible that additional instruments would use funding sources from outside NASA Planetary Science, too.

Sunday, December 19, 2010

Compelling Planetary Science Missions: Mars Background, Part 1 (MAX-C Rover)

This continues a series of posts inspired by a similar set of posts at Future Planetary Exploration blog selecting the 5 most compelling missions from the Planetary Science Decadal Survey list.

As should be no surprise, Mars is well represented in the Planetary Science Decadal Survey Mission and Technology Studies.  My personal selection of the most compelling Planetary Science missions probably goes against the prevailing preference of the Planetary Science community, so I'm certainly not going to be so rash as to skip favored Mars in my list of compelling missions.  The question then becomes which Mars mission should I select from the Decadal Survey's list?

The Survey includes 7 papers on Mars missions, but the choice isn't going to be as hard as that makes it sound.  Two of the papers are on the same general topic - a Mars Geophysical Network mission.  Three are on a 3-part series of missions to return Mars samples to Earth, and I'm simply going to rule out selection of the 2nd and 3rd of these missions in case the 1st fails or does not find samples that are interesting enough to deserve 2 additional missions to return.  There is a study on Sky Crane capabilities for the 2018 Mars opportunity which really boils down to a potential augmentation of the first of the Mars sample return missions.  Finally, there is an investigation on a variety Mars Polar Climate missions.  In other words, there are 3 basic missions to choose from, possibly followed by additional choices on the details of the selected mission.

Out of the 3 basic mission choices, the first of 3 Mars Sample Return missions surely has the most backing within the Mars science community.  That community has hungered for Mars Sample Return since, well, the Noachian period, it seems.  Not only that, but the 2018 MAX-C Caching Rover, which is to perform this first phase of the sample return sequence, is part of a multi-component international collaboration between NASA and ESA.  In 2016, NASA and ESA plan to launch the ExoMars Trace Gas Orbiter and an ESA Mars landing technology demonstration.  The Mars Trace Gas Orbiter is intended to investigate methane and other trace gases on Mars.  This will help select interesting destinations for the 2018 mission.  The orbiter will also serve as a telecommunications relay for the 2018 lander elements.

The 2018 NASA-ESA collaboration uses the Sky Crane landing method of NASA's Mars Science Laboratory.  However, instead of one larger rover, this time the payload is 2 smaller rovers.  ESA will contribute the ExoMars Rover, which will be able to drill 2 meters and collect soil samples.  The rover includes a variety of instruments to analyze the samples, drilled hole, and region around the rover.

NASA's 2018 contributions include the rocket, Sky Crane, and Mars Astrobiology Explorer-Cacher Rover.  This rover would be able to rove 20 km over 500 sols, retrieve 19 ten-gram rock core samples, and store them in a cache that is easily fetched by the next phase of the sample return (with a backup cache that also holds 19 samples).  The proposed rover instruments include a Panorama camera like the MER and Phoenix lander cameras to identify good sample sites and to give sample context, a NIR spectrometer for mineralogical mapping, an arm-mounted microscopic imager like the MER one, an Alpha-Particle X-Ray Spectrometer (APXS) similar to the MER and MSL ones to show what elements make up rocks the instrument is placed on, a Raman/fluorescence instrument to assess organics in rocks, and a sample caching system using an arm, drill, and caches. 

All of this in-situ science and sample return preparation is compelling, but the decision becomes more difficult when costs are considered.  The estimated FY15 cost (with the usual reserves) for NASA's contributions to the 2018 mission is about $2.2B.  That's quite a lot.  Now to be fair, the mission doesn't just do top quality in-situ science and take a big step towards the Mars sample return holy grail.  It also delivers an entirely separate and capable rover from ESA that can do work that MAX-C can't, which probably makes the 2 rovers more valuable as a team than they would be as rovers at separate locations.

Still. $2.2B ...

The Sky Crane study raises an interesting possibility.  Apparently, even with 2 rovers, there is plenty of room for additional payload for the mission.  For an additional $150M, a basic geophysical Network Pathfinder could be delivered to the Martian surface with the 2 rovers.  Mass delivery margin would be 29%, which is less than the 30% that is required, but this is close enough that a more detailed investigation might find ways to fit the additional payload comfortably within the mass margin like merging the Network Lander and landing pallet.  The Network Pathfinder would include a seismometer and meteorological sensors.  (More ambitious Network Pathfinder scenarios are also presented should the ESA rover not be assigned to the mission). 

Still, it might be nice to see that Sky Crane actually work on Mars for MSL before developing the MAX-C plan.

The bottom line is that this is a compelling mission, but it's expensive.  Is it compelling enough to be worth the expense (and therefore missed opportunities)?  Will I let my emotional annoyance at the fact that the mission uses a whole new rover design after all the trouble we went to design and build MSL and the MER rovers before that, and even uses the Sky Crane in a different way (2 rovers instead of 1) get the best of me?  Find out as I take a look at the Mars Geophysical Network and Mars Polar Climate mission concepts in the next 2 posts.

Tuesday, December 14, 2010

Compelling Planetary Science Missions: Enceladus Orbiter

For my first choice of compelling missions from the Planetary Science Decadal Survey Mission List, I picked the Lunar Polar Volatiles Explorer mission to send a rover to the Moon to assess the volatiles there.  This mission has great science and "astronaut scouting" potential.  However, in my first post in the series, I said that

Planetary Science should not have to be warped beyond recognition into a substitute Robotic Precursor program just because Congress isn't wise enough to adequately fund Robotic Precursors. 

While robotic "astronaut scouting" has a great deal of value, we should let Planetary Science be Planetary Science, and the Jupiter and Saturn systems (if I may group them together) are certainly top-tier Planetary Science subjects.  As a result, it's just a matter of choosing one of the Jupiter and Saturn missions from the Decadal Survey list for the second-place spot.

The front-runner for a Jupiter or Saturn mission is probably the Jupiter Europa Orbiter (JEO). There are a number of reasons to pick this one as my second most compelling mission:

The Vision for Space Exploration that this blog takes its name from specifically identifies robotic missions to Jupiter's moons (in that case the Jupiter Icy Moons Explorer (JIMO):

Conduct robotic exploration across the solar system for scientific purposes and to support human exploration. In particular, explore Jupiter’s moons, asteroids and other bodies to search for evidence of life, to understand the history of the solar system, and to search for resources;

However, the VSE also mentions missions to Saturn to follow Cassini, such as a Titan balloon.  I'd suggest that the VSE would have also considered Enceladus had it been written long enough after Cassini's work at Saturn started. 

A Europa orbiter has been studied in detail for many years.  Such a mission has been a high priority for the Planetary Science community for years, too.  JEO also has the potential for mutual observations with ESA's Jupiter Ganymede Orbiter if that mission is selected.  JEO would not only study Europa from orbit with instruments like a laser altimeter, ice-penetrating radar, and many others to find out about Europa's likely subsurface ocean, deep interior, ice shell, and surface, but it would also conduct numerous flybys of Ganymede, Callisto, and Io, and would be able to study the entire Jupiter system during its long tour towards Europa orbit.  It would also be able to conduct its mission years before an Enceladus orbiter.  In addition, researchers have had many years to consider the Galileo results, whereas Cassini is still in operation and could still change our perspective on just how an Enceladus mission should be conducted.

Now that I've made the case for JEO, I'm going to select an Enceladus orbiter as my second most compelling mission instead.  Enceladus wins me over for 2 reasons: the JEO price tag is a bit scary (even the Enceladus orbiter is not cheap), and Enceladus has those plumes!  The Titan Saturn System Mission would also study the plumes of Enceladus, to say nothing of also conducting a staggeringly ambitious investigation of Titan and the entire Saturn system with a spacecraft bristling with instruments and carrying a Titan lake lander and a balloon, but again the estimated cost is too high ($3.248B for the floor mission, not counting partner costs) for my faster-better-cheaper instincts.

The Decadal Survey looked into a number of Enceladus missions, including flybys, landers, and orbiters (see "Enceladus Flyby and Sample Return Concept Studies" on the Planetary Science Decadal Survey Mission & Technology Studies page).  The conclusion was that Enceladus landers would be better done after an orbiter mission, and orbiter missions would return more science than sample return missions of similar cost.  The "Enceladus Orbiter Concept Study" available on the same page gives more details about orbiter mission options.

Like JEO, an Enceladus Orbiter would conduct a tour of its destination planetary system before intense study of its destination moon.  The tour presented includes 40 flybys of Titan, Rhea, Dione, and Tethys, and 20 flybys of Enceladus itself, before the Enceladus orbit phase.  The main goals of the orbiter would be to study the source of the plumes, the composition, rate, and dynamics of the plumes themselves, the geology of Enceladus, the internal makeup of Enceladus including the subsurface ocean, scouting for future landers, and studies of other moons it would fly by.  Instruments would include a camera designed for the tiger stripe region of Enceladus, a thermal imaging radiometer, a mass spectrometer to measure the makeup of the plumes while the orbiter goes through them, a dust analyzer, and a magnetometer to study the moon's magnetic field for clues about the subsurface ocean as Galileo did for Jupiter's icy moons. 

Little technology development would be needed for the mission.  The baseline mission cost in FY15 dollars is projected to be $1.613B, including a significant amount for post-launch work like conducting the journey to Saturn and the science phase over many years.

Sunday, December 12, 2010

Compelling Planetary Science Missions: Lunar Polar Volatiles Explorer

See Part 1: Compelling Planetary Science Missions in this series of posts.

My first selection for the most compelling planetary science mission on the Decadal Survey list is the Lunar Polar Volatiles Explorer (LPVE).  From the Executive Summary:

The Lunar Polar Volatiles Explorer concept involves placing a lander and rover (with an instrument payload) in a permanently sun-shadowed lunar polar crater. The rover will carry a suite of science instruments to investigate the location, composition, and state of volatiles. While previous orbital missions have provided data that support the possibility of water ice deposits existing in the polar region, this LPVE concept seeks to understand the nature of those volatiles by direct in-situ measurement. A prospecting strategy is employed to enable lateral and vertical sampling only where higher hydrogen concentrations are detected, thus eliminating the criticality of statistically significant numbers and distributions of samples required by stochastic approaches.

As with most or all of the Decadal Survey mission concepts, there are more and less capable variants of this mission.  For example, some instruments that are in more capable variants could be dropped for a more affordable but less capable mission, and the rover power system could be based on batteries or ASRGs. 

Lunar volatiles are of scientific interest

because they record not only those released from the interior of the Moon during its geologic evolution, but also species derived from the solar wind, cosmic dust, and comets. Thus, the volatiles in the cold traps provide a record of the evolution of the Moon, the history of the sun, and the nature of comets that have entered the inner solar system over the last several billion years.

They are also of interest as potential resources for later exploration missions or even lunar and cis-lunar space infrastructure development.

The LPVE mission seeks to answer questions about the distribution, chemical and isotopic composition, physical form, and deposition rate of the volatiles.  We don't know the distribution of the volatiles, so we need a mobile explorer so we can test multiple locations.  That's where the rover comes in.  A neutron spectrometer on the rover is used to identify locations in the regolith with hydrogen.  The rover positions itself at the locations.  It's able to drill 2 meters into the regolith.  Instruments like another neutron spectrometer and an imager can be put in the drill hole to assess any volatiles there.  This allows the rover to identify the best sample locations within the hole.  The rover is able to retrieve samples from the drill hole and bring them to a gas chromatograph / mass spectrometer that heats them for analysis.

In addition to these "core" capabilities, "priority 2" instruments include X-Ray diffraction to measure the mineralogy of the retrieved samples, ground-penetrating radar and surface imaging for geological context, and a mass spectrometer to measure the lunar exosphere.

The fully-capable mission variant with an ASRG would be expected to last over a year and to be able to travel nearly 200 km.  It would be able to take 460 samples.  Battery variants would last a few days, be able to travel a few km, and be able to take about 20 samples.  Since this is my most compelling mission pick, I would be inclined to go for the full instrument suite and ASRG power supply in this case.  The difference in mission cost (at least in the estimates presented in the report) is minor, and the increased capability is significant.  The fully capable mission cost is estimated to be $1.132B in FY15 dollars; the battery mission cost is estimated to be $0.972B.  That's a lot of money in either case, but all of the missions in the Decadal Survey list are in the more expensive New Frontiers or Flagship mission classes.  If any funds are available from the Robotic Precursor line in upcoming years, one might imagine that funding line contributing an instrument or 2, making it easier for Planetary Science to run a fully capable LPVE mission.

In addition to the science, "astronaut scouting", and resource potential of this mission, I find the idea of a capable rover moving across hundreds of kilometers while drilling into the dirt to be compelling at a more basic level.  It seems that this sort of mission speaks to the handyman or "Dirty Jobs" part of our nature.  It just looks like a lot of fun.

Compelling Planetary Science Missions

The blog Future Planetary Exploration has a series of posts that present one view of the 5 most compelling planetary science missions from the list that the Planetary Science Decadal Survey is considering.  The posts describe missions that would most fundamentally advance our understanding of the solar system.  Using this measure, they do a good job of justifying the selection of the 4 missions described so far:

Thoughts on the Most Compelling Proposed Planetary Mission - This initial post in the series gives some background, and proposes the first of 3 missions for Mars Sample Return, the 2018 MAX-C rover, as the most compelling mission.  In spite of some skepticism about technical difficulty and cost, the opportunity to take advantage of the favorable 2018 Mars launch window, the Mars Surface Laboratory team's capabilities that would otherwise be dispersed, and the ability to work with Europe's ExoMars with subsurface sample capabilities is too tempting to pass up.

Compelling Missions - Part 2 - The Venus Climate Flagship, a scaled-down version of an ambitious Venus Flagship mission concept, is presented as the second most compelling mission.  This was posted a bit before the Decadal Survey list was released, so my interpretation is that it isn't so much a selection of the specific Venus Climate mission that's on the Survey's list, but rather that NASA would at least make some significant contribution to Venus studies, perhaps as part of a multinational Venus mission.

Compelling Missions 3 and 4: Icy Ocean Worlds - Missions to explore the icy Jovian moons and Saturn's Titan and Enceladus are next on the list.  The preference is for the Europa Jupiter System Flagship mission and one of the Enceladus orbiter missions with significant Titan capability, but

this combination would cost almost $6B.  Combine that with a $3-4B investment in Mars missions (which I predict will be the Decadal Survey's top priority) and a couple of Discovery missions, and that's pretty much the entire budget for missions next decade.  I also think that the Flagship missions may face have a couple of programmatic challenges.  First, NASA's last two choices for Flagship-scale missions, the Mars Science Laboratory and the James Webb Space Telescope, both experienced large cost overruns. ...

Several later posts look at lower-cost options to achieve some of the goals at the moons of Jupiter and Saturn.

While waiting for the last compelling mission, I decided to make my own series of "most compelling mission" posts with a different perspective.  These are supposed to be Planetary Science missions, so science return is an appropriate measure to use to compare the various missions.  However, I'd like to bring other factors into play, too.

I'd like to consider the Planetary Science missions in the context of our overall exploration and development of space.  A mission that helps NASA's human spaceflight program (whether Vision for Space Exploration, Flexible Path to Mars, or other approach) and/or traditional and new commercial space efforts will have an edge in my evaluation.  On the other hand, we are talking about Planetary Science, not Robotic Precursor missions.  Therefore, I will stick to the Decadal Survey list, which is full of missions with high-priority science content.  Planetary Science should not have to be warped beyond recognition into a substitute Robotic Precursor program just because Congress isn't wise enough to adequately fund Robotic Precursors.

For a fair comparison, I won't even consider the current 3 New Frontiers finalists (SAGE, a Venus lander mission, MoonRise, for sample return from the lunar South Pole-Aitken Basin, and OSIRIS-REx, for sample return from the asteroid 1999 RQ36), although I would otherwise be inclined to put them near or at the top of my list.

Decadal Survey: The Candy Store Posted - In order to play this game, you have to know what the proposed missions are.  This Future Planetary Exploration post gives the links and information needed to find out about the missions the Decadal Survey is evaluating.  The Decadal Survey reports are here.  The post also includes a handy table that summarizes the missions, their anticipated launch, arrival, and end dates, and a cost estimate or cost range for each mission.  Certain missions' cost estimates can be considered to be more reliable than others for various reasons (heritage, maturity of the particular mission proposal, etc), but I'll just take them as presented here.

Saturday, December 11, 2010

Twitter Account

I have a new twitter account: VisionRestore.

Also, I have some ideas for posts that have been simmering for quite a while, waiting for a chance to be written down.  I won't make any promises on when I'll finish, but I've finally started.

Tuesday, August 31, 2010

That Would Have Saved Me a Lot of Time

Summoning the Future By Remembering the Past - SpaceRef - Dennis Wingo's statement describes what I've intended, in a rather long-winded way, to say on this blog:

When the Obama administration's FY 2010 budget was introduced it was a breath of fresh air. The unsustainable Constellation program was cancelled and commercial spaceflight was embraced to support the ISS, and technology game changing missions funded that would lower the cost and provide a flexible path for exploration. However, the abandonment of a destination coupled with no real rational for what to do in Beyond Earth Orbit (BEO) exploration erased the vision (i.e. sense of purpose) part of the exploration plan.


The economic development of the solar system was the core value that made George W. Bush's Vision for Space Exploration exciting and worthwhile to the nation. The implementation was horribly done in the most wrong way possible. The Obama plan is the right implementation, but without the core value of economic development starting at the Moon, it is bereft of a moral underpinning.

The Obama administration's implementation is the right one, and the one that was intended with Bush's Vision for Space Exploration: make heavy use of robotic precursor missions, enable strong participation by commercial space and international partners, ensure that the effort is affordable over the long term, make steady progress, and encourage practical technology innovation.

The Flexible Path idea of performing easier deep space missions on the way to the surface of rocky worlds also makes sense. However, as distances increase, these deep space missions tend to become more difficult themselves, and to become less immediately useful in an economic sense. A hybrid of missions to the earlier, easier, and more immediately practical Flexible Path destinations done often enough to develop space infrastructure and commercial capabilities at those destinations, followed by a strong lunar surface push enabled by that infrastructure as planned in the Vision for Space Exploration, would keep the best parts of both approaches, while in the long run making the more distant deep space destinations on the Flexible Path more reachable.

The Administration's plan looks particularly strong in the area of technology - perhaps too strong for some - but this appearance could be changed simply by renaming some of the Flagship Technology Demonstrations to be simply "Missions", "Modules", and "Spacecraft". For the initial set we'd have the Space Tug spacecraft, the Inflatable Habitat ISS module, the Advanced Solar Electric Propulsion mission, and the Aerocapture mission ... and we'd still have a couple "Flagship Technology Demonstrations" as well.

Switching the Heavy Lift and Propulsion Technology effort to an affordable, modest increase in EELV or similar capabilities (e.g.: to 40-50mT to LEO) with development starting fairly soon would also give the Administration's proposal more of an operational flavor, while still leaving NASA with a strong technology portfolio.

Saturday, August 28, 2010

The Not-So-Great Compromise: Space Launch System and Multi-Purpose Crew Vehicle

In the previous posts in this series (see the tag below for the whole bunch), I speculated on what might be accomplished with a compromise between the Senate and the Administration in the Exploration areas of NASA's FY2011-FY2015 budget. My hypothetical scenario took the Senate Authorization bill as a baseline, since that bill gives some idea what would happen over several years. In particular, that bill a good idea what the Senate has in mind after the Shuttle is retired. In the other posts, I showed areas that could be made much better by shifting funds from the Senate's Heavy Lift rocket and Orion budget lines (or the Space Launch System and Multi-Purpose Crew Vehicle, as they are called in the bill). In this post, I'll look at what might happen to the HLV and astronaut spacecraft.

First, let's look at the funding that's available for the HLV and spacecraft in the Senate bill. Figures are in millions of dollars.


The Launch Support and Infrastructure Modernization program is

a program the primary purpose of which is to prepare infrastructure at the Kennedy Space Center that is needed to enable processing and launch of the Space Launch System.

We are therefore justified in lumping this funding with the other SLS/MPCV budget lines.

If we project the trend here through FY2015, we have an SLS/MPCV program that would cost $21B or so over that period. That's after $10B or so invested in Constellation.


Now we know how the Commercial Crew, Exploration Technology Development and Demonstration, Robotic Precursor, Space Technology, and commercially-oriented KSC upgrade budgets all but vanished.

Our hypothetical example compromise reduced the SLS/MPCV budget by $1B/year, or $5B total. That still leaves about $16B dedicated to the SLS and MPCV over this period. It would still be a huge NASA effort. The question is, would cutting their budgets by this amount do the same thing to SLS/MPCV that SLS/MPCV did to Commercial Crew, Exploration Technology, Robotic Precursor, Space Technology, and the rest in the Senate budgets? I don't think so. I think we could still have a viable HLV and spacecraft program with $16B over this time period, perhaps building on some of the work already done for Constellation.

First let's take a look at some of the provisions in the bill:

Requirements in new launch and crew systems authorized in this Act should be scaled to the minimum necessary to meet the core national mission capability needed to conduct cis-lunar missions. These initial missions, along with the development of new technologies and in-space capabilities can form the foundation for missions to other destinations. These initial missions also should provide operational experience prior to the further human expansion into space. ...
It is the policy of the United States that NASA develop a Space Launch System as a follow-on to the Space Shuttle that can access cis-lunar space and the regions of space beyond low-Earth orbit in order to enable the United States to participate in global efforts to access and develop this increasingly strategic region.

In addition, the MPCV should have the

capability to conduct regular in-space operations, such as rendezvous, docking, and extra-vehicular activities, in conjunction with payloads delivered by the Space Launch System developed pursuant to section 302, or other vehicles, in preparation for missions beyond low-Earth orbit or servicing of assets described in section 804, or other assets in cis-lunar space.

This is exactly the sort of capability that I argue for in what I call "step 2", the centerpiece, of the Flexible Path to the Moon. The ability to usefully access destinations like GEO, lunar orbit, and Earth-Moon Lagrange points is crucial. Having a vehicle that allows EVAs, rendezvous and docking, servicing of space assets, and other jobs in cislunar space is a key enabler of future exploration, commerce, science, and security applications. I'm pleased the Senate focuses so much on this sort of capability, rather than Constellation which focused mainly on Ares I/Orion ISS access, causing the next step, straight to the lunar surface in decades-long slow motion, to be a leap too far. Lunar access needs to happen in a more incremental fashion, building on self-sustaining cislunar space capabilities.

I am concerned with the development cost of the SLS and MPCV and its effect on other priorities, and I am also concerned with the eventual operations costs of these systems. However, at least they are focused on appropriate goals, even if those goals might better be achieved with commercially-derived launchers such as the ideas based on EELVs. However, in the spirit of compromise, let's see if we can make this Shuttle and Orion-derived cislunar space capability work with $16B through FY2015.

The Senate bill requires

The initial capability of the core elements, without an upper stage, of lifting payloads weighing between 70 tons and 100 tons into low-Earth orbit in preparation for transit for missions beyond low-Earth orbit. ... The capability to carry an integrated upper Earth departure stage bringing the total lift capability of the Space Launch System to 130 tons or more. ... Developmental work and testing of the core elements and the upper stage should proceed in parallel subject to appropriations. Priority should be placed on the core elements with the goal for operational capability for the core elements not later than December 31, 2016.

This brings up a number of areas where the Senate could relax requirements, and thereby increase the ultimate chance of success for the SLS while allowing other programs like Robotic Precursors and Exploration Technology to function. First, the Senate could relax the December 2016 date. I don't think there's anything urgent planned that day, so why not push it back a year or 2? The same goes for the MPCV, which has similar schedule requirements.

Another item that could be postponed is the upper stage. Do we really need to work on the upper stage in parallel with the core elements? Relaxing that requirement will allow the program to concentrate on the core elements, and thus increase the chance of success in that area, while at the same time allowing other programs (potential SLS payloads in some cases?) to survive, thus removing several sources of political opposition to the SLS. The core elements should keep us busy for quite a while. The upper stage could be considered much later.

The SLS also has a requirement to launch the MPCV. The Senate could change that requirement so the SLS doesn't have to go through the expense of crew rating. The MPCV could be morphed into an in-space only vehicle, with crew space access enabled by commercial crew services.

The MPCV could be scaled back to a CRV as the Administration suggested this Spring. This could be a temporary move to allow funding for other areas, and the MPCV could later reach full functionality (as an Orion-like vehicle or an in-space only - perhaps even reusable - vehicle).

The 70 and 130 ton requirements also present a potential difficulty. They seem to lead NASA to an inline SDHLV, since the sidemount options can't reach 130 ton capability with reasonable upgrade paths. However, NASA's sidemount and inline development cost estimates (PDF; see slide page 7) are $11B and $15B, respectively, if Shuttle is cancelled. The same charts show sidemount being delivered 2 years earlier than inline, and being a low-risk development compared to what they assess to be the high risk of inline options. In addition, the sidemount has an early Block I variant that could be performing missions even earlier, and that variant could be developed for much less than the combined Block I and Block II, perhaps allowing much of the Block II development work to be done after our years of concern FY2011-FY2015. A chart from the article Completed SD HLV assessment highlights low-cost post-shuttle solution shows the Block I development costs as $2.5B, although there would be other costs such as KSC infrastructure work.

In the universe of Shuttle-derived HLVs, inline options have their own advantages over sidemount variants (perhaps including growth options as well as safety if crew launch is to be supported), but if we put a premium on lower development costs because we want a compromise between the Senate and Administration plans, and thus want to have more funding for Exploration Technology Demonstration and Development, Robotic Precursors, Commercial Crew, or other Administration proposals, sidemount may be preferable overall, and good enough to meet the goals of the Senate.

In short, there are many ways the Senate can relax SLS and/or MPCV requirements, including schedule, performance, and functional capabilities. Depending on which of these options are taken, doing so could leave enough funding to bring other NASA budget lines from the Senate's non-viable condition to adequate, if limited, health. Even with such a compromise, the SLS and MPCV would still have every chance to succeed and contribute to NASA's work, and in fact they may be even healthier because they might gain payloads and spacecraft technology, as well as political support, from the other budget lines.

On the other hand, a stubborn line-in-the-sand approach would likely leave the SLS and MPCV with no technology and robotic precursor payloads, no exploration technology infusion into the MPCV, numerous political enemies, impossible schedules, difficult performance requirements, and expected functionality that will have to be dropped during development.

Wednesday, August 25, 2010

The Not-So-Great Compromise: Commercial Crew

If you've been reading this series of posts from the beginning, by now you will have noticed a pattern. In the areas of the NASA budget where there is some disagreement, the Senate bills cut funding for the Administration proposals so much that those areas cannot accomplish what they are intended to accomplish. I don't intend to discuss all of them. Commercial crew is one example that deserves some discussion, though. Here's how commercial crew fares in the Administration and Senate Authorization proposals (the Senate Appropriations Committee was less favorable to Commercial Crew in the year it covered, FY2011):


If we extrapolate the Senate's post-Shuttle, post-COTS figures, over FY2011-FY2015, Commercial Crew gets $2.3B from the Senate, and $5.8B from the Administration. That's a dramatic cut by the Senate, especially considering the concern that some members of the Senate say they have for astronaut safety. Some members of the Senate are also critical of one commercial space company in particular, but it seems that if the Senate has a Commercial Crew line but drastically underfunds it, only companies like that one with a focus of low cost will be able to compete for the money in the commercial crew line!

It should be noted that Senator Nelson has stated that the Senate's Commercial Crew funding would be stretched to FY2016, and would include the full amount requested by the Administration by then. That's a bit hard to believe. Look how far behind the Senate is by FY2013 already. Then consider that a sharp increase in Commercial Crew funding would have to come at the expense of some other program. What budget will be cut for this far-future promised Commercial Crew increase? Will it come from the SLS? Orion? I doubt it. Will the SLS or Orion suddenly need far less funding in FY2014? I doubt it. Quite the opposite is more likely. Those programs will either hit the usual schedule delays and cost overruns, or they will need to start thinking about big end-of-development costs for major tests, followed by high operations costs. The promised future Commercial Crew funds sound like Dr. Griffin's promise of commercial markets on the Moon based on government lunar infrastructure needs. That's a good idea, but when it's obvious that your particular transportation architecture isn't going to lead to government lunar infrastructure in the first place, the promise has a particularly hollow ring.

In my hypothetical improvement to the Senate's Not-So-Great "Compromise", half of the $1B/year shifted from SLS/Orion in favor of robotic precursor missions, exploration technology development and demonstrations, and commercial crew would go to the Commercial Crew line. Over 5 years this would increase the Commercial Crew amount from the Senate's $2.3B to $4.8B, which approaches the Administration's amount. If we continue Commercial Crew development funding for an additional year as suggested by Senator Nelson, and use the same funding rate, we get to $5.8B, which is the amount the Administration proposed.

Suddenly the Senate's Commercial Crew plan that is scaled to almost ensure a risky corner-cutting effort is changed to one that can support a healthy competition with both traditional and new competitors and their differing approaches. It won't be quite as fast as the Administration's original plan, and it won't have nearly as much KSC support, since in the Senate Appropriations report the 21st Century Launch Complex line must give NASA vehicles like the SLS priority, but it should enable multiple independent crew solutions that have enough funding to provide the safety and reliability features we need.

So, to sum up the last few posts, with a $1B/year shift from SLS/Orion to robotic precursors, commercial crew, and exploration technology, we should be able to turn those funding lines from completely non-viable shadows of their intended capabilities to functional, if quite limited, focused, and lean, versions of the original plan. At the same time this compromise can leave SLS/Orion in functional shape, too, as I'll discuss in the next post. Of course there is nothing magical about the $1B/year figure - others could work, too.

Does the plan give the Administration everything they want? No - it still limits and delays funds for robotic precursors, commercial crew, and exploration technology. It leaves the Space Technology line as it is now in the Senate bills. It leave Human Research as it is now in the Senate bills. It eliminates the Administration's Heavy Lift and Propulsion research and development line. It changes the purpose of the 21st Century Launch Complex line. It does all of this, but it gives the Administration some of what it wants by making some of its proposals viable. Unlike the current Senate bills, that would represent a real compromise.

Tuesday, August 24, 2010

The Not-So-Great Compromise: Exploration Technology Demonstrations and Development

Like the Robotic Precursor missions, NASA's proposed Exploration Technology and Demonstrations program includes 2 main categories of work. In this case, the 2 categories are Flagship Technology Demonstrations and Enabling Technology Development and Demonstration.

The Flagship Technology Demonstrations are major demonstrations of exploration technologies. These missions are expected to cost from $400M to $1B each. The Enabling Technology Development and Demonstration efforts are smaller (typically under $100M), and could include lab work, field tests, and even demonstrations in space.

NASA's initial FY2011 Enabling Technology Development and Demonstration (ETDD) Point of Departure Plans (PDF) included the following:

  • Lunar Volatiles Characterization - Demonstrate ISRU technology in a thermal vacuum chamber followed by testing on the Moon as part of a robotic precursor mission.
  • High Power Electric Propulsion - Demonstrate a prototype > 100 kW solar electric propulsion system in a thermal vacuum chamber with the intent to eventually demonstrating the technology in space under the Flagship Technology Demonstrations program.
  • Autonomous Precision Landing - demonstrate an autonomous landing and hazard avoidance system on Earth, perhaps using a VTVL landing vehicle as a carrying platform. This would eventually lead to a test on a body like the Moon.
  • Human Exploration Telerobotics - Demonstrate telerobotics to and from the ISS to simulate telerobotics for NEOs or Mars.
  • Fission Power Systems Technology - Demonstrate components of a 40 kW fission power system.

NASA's ambitious Flagship Technology Demonstrations Point of Departure (POD) Plans (PDF) includes an initial set of 4 missions to demonstrate 6 exploration technologies. The initial set of Flagship exploration technologies is:

  • Advanced Solar Electric Propulsion - including advanced solar arrays
  • In-Orbit Propellant Storage and Transfer
  • Lightweight/Inflatable Modules
  • Automated/Autonomous Rendezvous and Docking (AR&D)
  • Closed-Loop Life Support - demonstrated in the new module on the ISS
  • Aerocapture and/or Entry, Descent and Precision Landing

These initial technologies would be demonstrated on 4 missions:

Like the Robotic Precursor line, the Senate drastically underfunds NASA's Exploration Technology Development and Demonstration line compared to the Administration's plan. Let's compare the Administration and Senate Authorization proposals for this account. Figures are in millions of dollars:


If we extend the Authorization Committee's post-Shuttle pattern to FY2015, we see that there is a about a 4-fold difference: about $7.8B in the Administration budget compared to about $2.0B in the Senate budget.

Let's see how much we can accomplish with the 2 budgets. This will require making some assumptions. Let's assume NASA doesn't scale its technology efforts to brush against the upper limits on the Flagship and Enabling programs (i.e. $1B and $100M, respectively), but when faced with the typical setbacks and delays in aerospace work, the projects wind up costing about those amounts anyway. In that case, how much can we get done with the 2 approaches?

I've described NASA's initial set of technology efforts. However, these are only the initial set. Even if we assume the 4 Flagship missions cost $1B each, and the 5 Enabling Technology efforts cost $100M each, we are still only at $4.5B of the planned $7.8B in the Administration budget. There is room for quite a few more Flagship Demonstration missions and Enabling Technology developments in that budget. Not only that, but for the later missions, the AR&D space tug vehicle will have completed a diverse set of demonstrations, so we could expect later Flagship missions that use the space tug to be cheaper or to demonstrate even more "payload" capabilities, since they likely would not have to fund development of new AR&D vehicle capabilities.

In contrast, the Senate doesn't allow us to accomplish much with this line. We could fund the initial 5 Enabling Technology efforts for $500M. We would have trouble taking successes from these efforts to the next level, though, in cases where the intent is to move the technology to a Robotic Precursor or a Flagship Technology Demonstration, since those 2 lines are drastically underfunded in the Senate bills. We could find ourselves with a number of technologies successfully demonstrated on Earth that wind up dying on the vine.

In addition to the 5 smaller ETDD efforts, we could also fund the first Flagship Technology Demonstration mission, and start funding the 2nd one. At that point, with the cost assumptions I made, we will have exhausted our funds. The first Flagship Technology Demonstration mission will have demonstrated limited autonomous rendezvous and docking capabilities, an advanced solar array system like DARPA's FAST array, and a 30 kW solar electric propulsion system. That would be the end through FY2015.

In other words, of the 6 initial technologies proposed for the Flagship line, with the Senate we will have demonstrated 1 instead of what we could expect with the Administration budget: all 6 and several more.

The advanced solar array and solar electric propulsion system should find many practical uses in commercial, military, and civil applications, unlike, say, a NASA heavy lift rocket where NASA has to maintain an expensive infrastructure whether or not it uses it. Thus, completing only FTD-1 is not a complete loss. In fact, it is the potential for such practical uses, and the associated motivation non-NASA (commercial, government, or academic) partners (in this case probably including DARPA) have to demonstrate these technologies so they are available for production use, that will provide the additional focus (and perhaps funding) that will help these missions to succeed.

However, as practical as it is, by itself, even a successful demonstrate of the solar electric propulsion and advanced solar array technology on FTD-1 will not be enough to enable cost-effective, productive, and safe BEO astronaut work. It will have nice side benefits, but by itself it will not make much difference to exploration, its main purpose.

Essentially the Senate bill as it stands would cause the exploration technology effort to fail. With that bill, we will do what we can with existing technology, and that will be the end of it.

Is there a compromise between the Senate and Administration proposals that would allow the exploration technology effort to succeed, even though the ambitions of the effort would be more limited than those that NASA originally proposed? I think there is.

Earlier, I used an example $1B/year increase in robotic precursors, commercial crew, and exploration technology over the Senate proposal at the expense of the HLV, Orion, and Shuttle budgets as a sample compromise between the Senate and Administration proposals (i.e. this would fall much closer to the Senate proposal than the Administration proposal). In this rough example, Exploration Technology received an additional $250M/year, on average, compared to the Senate bill. That leaves it with about $3B from FY2011-2015 instead of the Senate's $2B or the Administration's $7.8B. In terms of money, we aren't going far from the Senate proposal here. What can we do with $3B given the above assumptions?

With $3B instead of $2B from FY2011-FY2015, with the assumptions I made, NASA should be able to implement the 5 initial Enabling Developments for $500M, and the first 2 Flagship Technology Demonstrations, which include solar electric propulsion, advanced solar arrays, and autonomous rendezvous and docking work in the first mission, and propellant depot technology as well as additional autonomous rendezvous and docking (space tug) work in the second mission. That achieves 2 of the 6 initial Flagship technologies, and most of the 3rd (AR&D vehicle/space tug). It's starting to get better.

The remaining funds from the $3B, $500M, should be able to achieve much of the work of the 3rd Flagship mission, which includes and inflatable habitat demonstration, closed-loop life support demonstrations, and the rest of the AR&D vehicle work. Perhaps with $500M the Exploration Technology line could fund the rest of the AR&D work, finishing the 3rd Flagship objective and getting the inflatable habitat to the ISS. Is it possible to build the inflatable habitat in the FY2011-FY2015 timeframe in the first place if that's where the technology money runs out?

The FY2011-FY2015 budget outlook includes a $2B boost to the ISS budget

to fully utilize the Station’s R&D capabilities to conduct scientific research, improve our capabilities for operating in space, and demonstrate new technologies

It seems to me that the inflatable habitat demonstration on the ISS, as well as the closed-loop life support demonstrations that would take place mainly on this addition to the ISS, could be moved within this enhanced ISS budget line. All of this work adds to the Station's capabilities, uses the Station's existing R&D capabilities, and demonstrates new technologies. If this effort is a little bit too big for the enhanced ISS budget to fund, the ECLSS demonstration, which includes numerous smaller technologies, could be scaled back a bit, pieces of it could be introduced more gradually than in the original plan, or some funding could come from the rest of the exploration technology line, if any money remains there (e.g.: if the AR&D work for FTD-3 doesn't use up the $500M). A commercial inflatable habitat partner might also pitch in some funding, for example, if they were allowed some control over the inflatable habitat for non-NASA commercial revenue purposes.

If this can be arranged, we will have achieved 5 of the 6 original Flagship technology goal, perhaps with only partial credit on ECLSS. Only aerocapture remains from the initial set of Flagship technologies. I consider aerocapture to be a lower priority, since it seems to have less immediate non-NASA (i.e. commercial, DoD, etc) applicability, and thus does not help as much to build the space industry, which seems as important as developing the specific technologies themselves for exploration purposes. Also, if we are using SLS/Orion, I don't see aerocapture at Earth as the most immediate priority. Mars aerocapture may be important some day, but astronaut Mars surface missions will be very far in the future indeed if we're spending lots of money on SLS/Orion, so again aerocapture is not a near-term (i.e. next couple decades) concern.

Aerocapture could come in handy for near-term robotic science missions, so I'd suggest taking the remaining Exploration Technology funds (hopefully $100M or $200M, depending on the details of the 3rd Flagship mission funding), and encouraging a science mission to demonstrate smaller-scale aerocapture as a first step. The NASA robotic science DISCOVERY 2010 Announcement of Opportunity already includes a $10M increase on the lander mission cost cap if such a Discovery mission uses aerocapture, and a $20M increase in the cost cap on an orbiter mission if such a Discovery mission uses aerocapture. A comparatively large supplement from the Exploration Technology line could perhaps be enough to get an initial demonstration of aerocapture on a robotic science mission. This would allow us to achieve all of the initial objectives of the Flagship line, with the caveat that some ECLSS demonstrations could be delayed or forgone, and aerocapture could be demonstrated on a smaller scale than originally planned, simply by increasing the Exploration Technology budget a little bit closer to the Administration's proposal, and by using some ISS funds for work that's appropriate for it.

Of course this is still not nearly as ambitious as the original Administration plan, which included several additional, if less well-defined, technology demonstrations that would follow the first set (for example, more ambitious aerocapture and high-performance propulsion demonstrations). On the other hand, it does allow significant progress on technologies that can enable more ambitious and cost-effective astronaut missions, more ambitious and cost-effective support of astronaut missions via cargo deliveries, and a more successful space industry as NASA's commercial and government partners make use of the demonstrated exploration technologies with multiple uses. The ability to make steady progress on the original 6 Flagship missions would also give some reason to hope that those Enabling Technology developments that need a new Flagship Technology Demonstration mission to reach operational status would eventually find such a mission.

The current Senate "compromise" allows the Senate to achieve its objectives through the SLS HLV, Orion, Shuttle, and SLS-oriented KSC upgrades, but it doesn't allow the Administration to achieve its exploration technology development objectives. A modest shift from the pure Senate plan towards the Administration plan, while still keeping most of the SLS, Orion, Shuttle, and KSC upgrade funding in place as the Senate proposed, would allow much of the Administration plan to be achieved, too. Such a compromise would be advantageous for both sides, since the new exploration technologies could support the SLS and Orion while the SLS and Orion provide another reason to develop the new technologies. In addition, funding the new exploration technologies enough to make progress on them would take away a considerable amount of objection to the SLS/Orion approach from various communities (i.e. Science, Commercial Space, grass roots, etc). In other words, it's even in the interest of the SLS/Orion advocates to fund exploration technology development enough so those developments can succeed.

Friday, August 20, 2010

The Not-So-Great Compromise: Robotic Precursor Missions

In spite of the view held in some circles that "all we need is a good map", robotic precursor missions are essential if we are going to rocky destinations like the Moon, NEOs, Mars moons, or Mars, especially if we want to do so in an affordable, safe, and productive manner. We certainly do need a good map, and in fact we need many kinds of good maps. We also need much more than maps from robotic precursor missions. Example jobs for robotic precursor missions include assessing hazards to astronauts, measuring local resources, practicing use of those resources, performing various other technology demonstration tests, and evaluating potential locations for astronauts.

Let's compare the Administration and Senate Authorization proposals in terms of robotic precursor missions. Figures are in millions of dollars:


If we extend the Authorization Committee's pattern to FY2015, we see that there is a 6-fold difference: about $3,000M in the Administration budget compared to $500M in the Senate budget.


NASA presented some early ideas on what they would like to do with a well-funded robotic precursor mission line. In May, during an exploration workshop, the FY 2011 Exploration Precursor Robotic Missions (xPRM) Point of Departure Plans (PDF) included:

  • a series of main robotic precursor missions ($500M - $800M each)
  • a series of small "Scout" missions ($100M - $200M each)
  • development of instruments to be flown on science missions
  • data systems, research, analysis, and sensor technology development
The initial set of proposed missions included:

FY----Large Mission----Scout----Hosted Instrument
2014..NEO Rendezvous...yes......yes
2015..Lunar Lander..............yes
2016..Mars Orbiter.....yes......yes
2018..Mars Lander......yes......yes
2019..NEO Rendezvous............yes

This would have strained the available $3B budget from 2011-2015, but if some funding from later years is counted, perhaps it could be done. Probably the most serious flaw in this series of missions is that it emphasizes Mars too much, considering that Mars is such a distant goal in NASA's exploration schedule. NASA needs to focus much more on nearer-term destinations if it wants to succeed in the earlier steps on the way to Mars. We need multiple robotic precursor missions for our next rocky destination, whether that destination is the lunar surface as described in the Flexible Path to the Moon, or NEOs as described in the Augustine Flexible Path to Mars.

A more recent presentation shows that NASA's evolving robotic precursor plans are addressing both the funding and the focus problems I just mentioned. In the Explore NEOs Objectives Workshop (Explore NOW), the robotic precursor plans presented in the updated version of Exploration Precursor Robotic Missions (xPRM) Point of Departure Plans (PDF) include:

FY----Large Mission----Scout----Hosted Instrument
2015..Lunar Lander.....yes......yes
2016............................yes 2017..NEO..............yes......yes

One of the large Mars missions has been replaced by a NEO Scout. This makes funding the line more achievable (although still a stretch) with $3B, especially if we can count some funds in later years. In addition, the NEO missions are done sooner, allowing the results from these missions to inform astronaut NEO missions. Finally, with 3 NEO missions instead of 2 (1 of which was late in the original plan), there is a serious enough focus on NEOs to really be able to help the astronaut missions to NEOs succeed. On the Flexible Path to Mars, later robotic precursor missions could focus on the Moon or Mars and its moons, depending on what branch of that path is taken.

Ideas for the 2 main NEO missions include a NEO Telescopic Survey to identify a better selection of NEOs reachable on early deep space astronaut missions, or a NEO Rendezvous mission that could focus on a single NEO or give more high-level information about multiple NEOs using multiple small spacecraft. The 2 larger NEO missions are anticipated to cost in the $640M-$840M range through their complete life cycle.

Now let's go back to the Senate budget. Assuming their FY2011-2013 trend is kept, that budget gives $500M through FY2015. Another Senate committee's version of the budget only gives $44M in FY2011, so it would only have $444M through FY2015.

There is not enough money to run a single robotic precursor mission in the $640M-$840M class NASA envisions with the Senate budget even if that budget is projected through FY2015.

The Senate limits the robotic precursor line to 1 or 2 very small missions, 1 or 2 instruments, and supporting work like research and data systems. It acknowledges this limitation by giving the funding line the title "Robotic Precursor Instruments and Low-Cost Missions". I frequently find myself in favor of a strong emphasis on small missions, but there really needs to be a healthy mixture of smaller and larger missions.

Based on the lack of robotic precursor mission funding, my conclusion is that the Senate bills for all intents and purposes rule out any aspirations NASA might have for astronauts reaching rocky world destinations like the Moon, NEOs, Mars moons, and Mars.

Now we come to the question of compromise. Is there a viable compromise between the Administration and Senate proposals that achieves important objectives? I think there is if the Senate gives some ground on Heavy Lift rocket and Orion funding. Over the next few posts, I'll use an example of shifting a billion dollars or so per year from these lines to robotic precursors, exploration technology, and commercial crew. This would still give the Senate what it wants: funding on a massive scale for a Shuttle-derived rocket and Orion spacecraft, eventually flying astronaut missions beyond LEO. It would also allow efforts like the robotic precursor line to function, even if not as spectacularly as planned in the original FY2011 budget proposal. In my examples, I'll make a crude breakdown (ignoring details like funding profiles to match realistic project work levels over time) for the hypothetical shifted $1B/year by dividing it as follows:
  • 25% ($250M/year on average) for Robotic Precursor Missions
  • 25% ($250M/year on average) for Exploration Technology Development and Demonstrations
  • 50% ($500M/year on average) for Commercial Crew
In my examples, these amounts would be added to the original Senate plans for these 3 funding lines, thus representing a compromise between the Senate and Administration budgets.

With this budget compromise, Robotic Precursor Missions would see a dramatic increase from $500M to $1,750M from FY2011-FY2015. That doesn't come close to the Administration proposal, but it's a compromise. Can the Robotic Precursor Mission line do useful work with this amount of money? I think so. Unfortunately, that level of funding would probably require NASA to eliminate most or all robotic precursor missions to all destinations beyond their first expected destination for astronauts. If the first destination is NEOs, the plan might be cut back to something like this:

FY----Large Mission----Scout----Hosted Instrument

A similar view might hold for lunar robotic precursor missions if we choose to go to the lunar surface as the first rocky destination instead of NEOs.

With missions with life cycle costs from $640M-$840M, we could squeeze a couple large missions and a couple Scouts, as long as we stay much closer to the $640M side than the $840M side for the main missions. We might have to trim some capabilities off of those missions to make sure that happens, or we might have to turn one of the bigger missions into a Scout or 2. Either way, we go from the Senate's completely non-functional Robotic Precursor plan to one that is limited, but that can help chart the course for astronaut missions.

Would this be enough for safe, cost-effective, and productive astronaut missions? I suspect it would require additional help from NASA's Planetary Science community. If NEOs are the first destination, SMD might need to set up a NEO-specific funding line similar to the existing Lunar and Mars ones. With cooperation with NASA SMD, commercial space, non-profits, and international missions, we might even be able to form a quite capable, if focused, Robotic Precursor line.

The Not-So-Great Compromise: Introduction

It's an interesting time in the NASA exploration battle that has been raging since 2005 and the introduction of the Ares rockets that eliminated most of the Vision for Space Exploration, and made the rest of that vision unattainable. The Obama Administration's proposal to emphasize technology development, commercial participation, and robotic precursor missions, all essential parts of the Vision for Space Exploration, but to do so using a Flexible Path to Mars sequence, has met with counter-proposals from the House and Senate. Most supporters of the technology/commercial/precursor approach seem to favor the Senate's proposal over the House proposal, even though the House fully funds the Administration's ambitious Space Technology line. This is probably because the House proposal essentially wipes out robotic precursors, exploration-specific technology development and demonstrations, and commercial crew transportation, while continuing the troubled Ares rockets. I won't discuss the House proposal in any more detail, since there seems to be considerable opposition to it in Congress and industry, since most of its supporters in industry seem to have no preference for it over the Senate budget, since NASA and the Administration haven't favored it, and since I personally don't find it to be credible. It has some isolated interesting ideas that may see the light of day, but as a total package it utterly fails.

Does this mean that the Senate proposals are good? I don't think so. The Senate Authorization and Appropriations bills and reports have serious flaws. The Senate bills have been described as great compromises, but as they stand they merely compromise NASA's ability to explore and encourage the development of space. However, if blended with some of the Administration proposals, the Senate bills do, perhaps, put us within reach of a NASA that can achieve important objectives on a realistic budget. Somewhere between the Senate and Administration proposals is a real compromise that is better than either extreme.

One point of view holds that both House and Senate bills are valid compromises because they give the Administration exactly what it asked for in many areas, such as keeping and vigorously using the ISS, increasing Earth Observation funding, adding Aeronautics programs to fund things like green aviation, restarting Pu-238 production, and boosting NEO search funding. However, I wouldn't characterize these agreements as compromises. Senator Hutchison, a key player in the Senate discussions, will be just as supportive of ISS funding and JSC ISS work as the Administration. The Democratic House and Senate are going to be just as inclined as the Administration to support environment-friendly programs. The other changes are small in budgetary terms. No, any compromise should be viewed strictly through the lens of the areas where there is disagreement, like technology funding, robotic precursor missions, commercial space, and government-owned heavy lift rockets. In these areas of dispute, the Senate's cuts to Administration proposals are so drastic that, in their current form, they can't be seen as compromises at all.

They can, however, be useful as starting points for a real compromise.

In the next few days I plan to discuss some of the budgetary lines in more detail so we can get an idea what a real compromise might look like. Since the Senate Authorization bill covers 3 years compared to the 1 year Senate Appropriations bill, I will focus mainly on the Authorization bill. That bill gives a better picture of where we might go over the course of years with the Senate's approach, and the 2 Senate bills are not all that different from each other anyway.

Monday, May 17, 2010

Flexible Path to the Moon: Science, Commerce, and Security at Beyond-LEO Earth Orbits

The following lists illustrate some of the science, commerce, and security activities that can take place at, or that can be enabled by capabilities at, Geosyncronous orbit and other beyond-LEO satellite orbits.


  • Deploy, assemble, inspect, and/or service GEO science missions (for example, certain NASA and NOAA satellites observing Earth from GEO)

  • Inspect GEO satellites. This could include taking samples of old satellites to assess micrometeorite damage, for example. This type of analysis can also be useful for economic and security purposes.

  • Deploy, assemble, inspect, and/or service GEO commercial missions (for example, communications satellites)

  • Enable commercial providers of satellite assembly or servicing capabilities
  • Space tourism - history or engineering tour of current or historical GEO satellites (no touching the exhibits, please)
  • jump-start capabilities that can be useful for commercial missions for other destinations (for example: fuel depots, satellite deployment, assembly, inspection, and/or servicing nodes, low-cost space access, etc)


  • Deploy, assemble, inspect, and/or service GEO security missions (for example, military satellites)

  • Observe other nations' satellites

  • Jump-start capabilities that can be generally useful for security missions (for example: fuel depots, satellite deployment, assembly, inspection, and/or servicing nodes, low-cost space access, etc)

Flexible Path to the Moon: Science, Commerce, and Security at Earth-Moon Lagrange Points

The following lists illustrate some of the science, commerce, and security activities that can take place at, or that can be enabled by capabilities at, Earth-Moon Lagrange points.


  • Deploy, assemble, inspect, or service Lagrange Point science missions (for example, Astrophysics or Heliophysics observatories). These could include Earth-Sun Lagrange Point science observatories assembled or serviced at Earth-Moon Lagrange Points, with the ability to transfer between assembly/servicing and operational Lagrange Points

  • Measure solar wind

  • Prepare for later science or exploration missions to the lunar surface or deep space (perhaps using exploration assembly or servicing nodes)

  • Compare ISS science results to results at Earth-Moon Lagrange Points (for example, considering Earth's magnetosphere)


  • Encourage development of commercial services that can deploy, assemble, inspect, or service Lagrange Point science missions (for example, Astrophysics or Heliophysics observatories). These could include Earth-Sun Lagrange Point science observatories assembled or serviced at Earth-Moon Lagrange Points, with the ability to transfer between assembly/servicing and operational Lagrange Points. The capabilities developed here could be applied to commercial customers, possibly at other locations

  • Encourage the development of commercial services that can assemble exploration missions for the government

  • Encourage the development of commercial nodes at Earth-Moon Lagrange Points with the government as a customer


  • Jump-start capabilities that can be useful for security missions for other destinations (for example: fuel depots, satellite deployment, assembly, inspection, and/or servicing nodes, low-cost space access, etc)

Flexible Path to the Moon: Science, Commerce, and Security in Lunar Orbit

The following lists illustrate some of the science, commerce, and security activities that can take place in, or that can be enabled by capabilities in, lunar orbit.


  • Deploy, assemble, inspect, and/or service robotic lunar science missions

  • Contribute to lunar sample return missions

  • Deploy, assemble, inspect, and/or service robotic Earth observation missions for "full Earth" measurements

  • Use telerobotics for missions at the lunar surface. This can be done from Earth, but lunar orbit may provide some advantages depending on mission details: shorter communications delay (including communications relays), less requirements for communications infrastructure, more direct communications paths at times, simulation of Mars or Venus telerobotics from orbit.

  • remote sensing observations from the astronauts' spacecraft

  • test missions for operations at more distance locations (for example, Mars or Venus telerobotics, direct remote sensing, sample return, or deploying, assembling, inspecting, or servicing robotic spacecraft)

  • jump-start capabilities that can be useful for science missions for other destinations (for example: fuel depots, satellite deployment, assembly, inspection, and/or servicing nodes, low-cost space access, etc)

  • prepare for later lunar surface astronaut science missions (for example: exploration mission assembly or servicing infrastructure in lunar orbit)


  • jump-start capabilities that can be useful for commercial missions for other destinations (for example: fuel depots, satellite deployment, assembly, inspection, and/or servicing nodes, low-cost space access, etc).

  • Space tourism at lunar orbit (for example, for lunar views)

  • Support of commercial robotics at the lunar surface

  • Prepare for later commercial lunar surface missions (for example, exploration assembly/servicing node in lunar orbit)

  • jump-start capabilities that can be useful for security missions for other destinations (for example: fuel depots, satellite deployment, assembly, inspection, and/or servicing nodes, low-cost space access, etc)

Flexible Path to the Moon: Cislunar Space

This post continues yesterday's discussion on NASA's cislunar space plans on the Flexible Path to Mars by comparing those plans with those of the Flexible Path to the Moon at the same destinations.

The Flexible Path to the Moon includes three phases:
  • establishing a solid foothold in LEO with commercial and international participation as well as technology development while robotic precursors blaze an exploration trail
  • moving beyond LEO to cislunar space destinations like GEO, lunar orbit, and Earth-Moon Lagrange points
  • returning to the surface of the Moon

Each phase is intended to be self-sustaining, to produce useful economic, science, and security benefits, to develop reusable space infrastructure, and to enable more ambitious steps.

It's natural to concentrate either on the first or the last of the three steps on the Flexible Path to the Moon. The first step, establishing a foothold in LEO while robotic scouts move ahead, is our most immediate concern. In the context of the 2011 NASA budget, the NASA human spaceflight exploration work for the next several years will be entirely devoted to this step, although with a view towards the Augustine Flexible Path to Mars. Most of our near-term decisions center around this first step, so it's no surprise it's of great interest.

It's also natural to emphasize the activity that will take place on the lunar surface. The Moon is an entire world waiting to be explored and developed. Although the activities to be done on the Moon's surface would be quite different from the ones performed during the Apollo missions, Apollo gives us a conceptual framework that allows us to easily imagine what might be done there. Fiction and our experience on Earth fill in the gaps that Apollo leaves out. Not only that, but reaching the Moon is the central destination and ultimate goal of the Flexible Path to the Moon. Right?


In the Augustine Flexible Path to Mars, it is probably fair to say that Mars is the ultimate, central destination. The Flexible Path to Mars is about exploring new places to learn about them while getting closer to exploring and learning about Mars.

In the Flexible Path to the Moon, the Moon is actually not the ultimate, central destination, in spite of the name. The Flexible Path to the Moon is intensely focused on the Earth. It is about exploring and developing LEO, cislunar space, and the Moon for the benefit of people on Earth. This can be illustrated by considering the second step on the path, developing cislunar space.

Apollo 8's lunar flyby wasn't our goal in the 1960's. The Ares rockets weren't intended to allow astronauts to linger at cislunar space destinations or to develop infrastructure there. Even in the Augustine Flexible Path to Mars, the cislunar space destinations are treated as mere stepping stones on the way to adventuresome excursions to more distant destinations like asteroids and Mars moons.

In contrast to the Apollo, Constellation, and Flexible Path to Mars approaches that minimize beyond-LEO cislunar space destinations, the Flexible Path to the Moon treats the work that can be done and the benefits that can be gained at GEO, Earth-Moon Lagrange points, and lunar orbit as the heart of the Flexible Path to the Moon. All of the steps on this path can produce benefits for the taxpayers on Earth, but it is the intense focus on deriving economic, security, science, and other benefits from the cislunar space destinations where the Flexible Path to the Moon contrasts the most with Apollo, Constellation, and the Flexible Path to Mars.

In the Flexible Path to the Moon, cislunar space destinations "between" LEO and the lunar surface are not like the empty airspace between your departure and arrival locations on a plane trip, even though there are no rocky bodies there. These destinations are like unpopulated versions of the American West that the new nation on the Eastern seaboard (LEO in our analogy) looked forward to exploring and developing on the way towards the future great cities on the Pacific ocean (the Moon in our analogy).

In other words, cislunar space is not just a "middle-man" between LEO and the lunar surface. We don't want to skip past this step as quickly as possible on the way to the Moon, because this step not only makes the lunar surface more accessible in the long run, but it also serves the same sort of purpose that the Moon itself serves.

Here are a few observations about the activities that can be done at the cislunar space destinations:

  • Reaching these destinations is easier than reaching more distant destinations like NEOs or Mars moons. We can get there affordably and safely with considerably less capability (low-cost commercial operations, new technology, propellant depots, heavy lift, etc) than these more difficult destinations. We can also be more confident that a development effort to reach these destinations will succeed.
  • Reaching these destinations helps enable later exploration at the lunar surface.
  • Reaching these destinations and spending the considerable time and effort to make the most of these destinations before venturing beyond them helps make later exploration and development at the lunar surface more affordable, achievable, and sustainable, even though it may delay the beginning of these missions.
  • Reaching these destinations helps enable later exploration at more distant Flexible Path to Mars destinations (for example, NEOs and Mars orbit), as implied by the Augustine Committee report.
  • Reaching these destinations and spending the considerable time and effort to make the most of these destinations before venturing beyond them helps make later exploration at more distant Flexible Path to Mars destinations more affordable, achievable, and sustainable, even though it may delay the beginning of these missions.
  • Making the most of these destinations enables a wide variety of commercial space activity. This activity in turn should strengthen the space industrial base, add jobs, and enable more useful services that can be enjoyed by the taxpayer.
  • These destinations offer benefits across the spectrum of space science fields: Earth science (assembly/servicing, full-Earth data collection), Heliophysics (observatory assembly/servicing), Astrophysics (observatory assembly/servicing), Planetary Science (lunar telerobotics, lunar sample return, lunar remote sensing from astronaut spacecraft, lunar orbiting satellite assembly/servicing, preparation for astronauts at the lunar surface, test and setup for later planetary science at more distant destinations), and various ISS sciences (similar activities outside LEO).
  • The capabilities enabled and encouraged by these destinations (satellite assembly/servicing/inspection, fuel depots, reusable space infrastructure, reusable in-space transportation, etc) are highly useful for national security purposes.
  • Many of the activities at these destinations require some sort of space infrastructure like satellite servicing or exploration spacecraft assembly nodes. This may bring visions of multi-decade development efforts to build facilities like the ISS, followed by difficult logistics requirements. This need not be the case. These nodes can be considerably smaller than the ISS, and could be focused on specific tasks. Also, these nodes do not need to be permanently occupied (and given radiation considerations may very well not be), so the logistics requirements could be much easier than those of the ISS.
  • These destinations provide an interesting variation on space stations. They are harder to reach than LEO, but they have advantages, too. These destinations don't present a requirement for reboost because of atmospheric drag as the ISS orbit does. They don't have the same sort of space debris problem. Microgravity work would not have to suffer from perturbations due to Earth's imperfectly symmetrical gravity field. Instruments and materials would not suffer the same sort of weathering.

These benefits the cislunar space step are important, but what about the Moon? Even if our reach falls short and we don't get to the lunar surface sustainably during this effort, we will have accomplished much if we develop cislunar space. If we do establish ourselves on the Moon in a long-term sense, our initial efforts will still be centered on the cislunar space destinations, and thus on benefits to the people on Earth. Our mission at the lunar surface is not to do lunar surface science, although we may do some of that. It is not to set up a permanent lunar colony, although our work in this phase may bring us closer to such a colony. Our purpose on the lunar surface is to use the Moon as a force multiplier to increase our productivity at the cislunar space destinations.

This will be done in part through the demands that the lunar surface will place on the cislunar space destinations. Our capabilities and infrastructure at these destinations will need to grow to satisfy the demands of the lunar surface work.

It will also be done through the use of lunar resources. Lunar resources can help make lunar surface work affordable, but they will eventually be needed in cislunar space destinations, too. The initial cislunar assembly, servicing, and depot capabilities will be greatly enhanced through the use of these lunar resources.

The work on the lunar surface benefits the taxpayer on Earth mainly through the improvements this work enables in cislunar space. The lunar surface and cislunar space destinations become mutually supporting in a virtuous circle of sustainable and even expanding commercial, industrial, and science capabilities and infrastructure.

In the long run we may ultimately use lunar resources to make closer (i.e. LEO) or more distant (i.e. NEO, Mars moon, etc.) activities more affordable. The development of these resources may even result in a strong permanent presence on the Moon that ultimately develops its own reasons for being. However, with the Flexible Path to the Moon, this process will start by using lunar resources to address needs in cislunar space, which in turn address needs on Earth.