Thursday, November 21, 2013

In Case Dennis Tito was Wondering if I Can Help Him Spend His Money

My initial gut feeling on looking over the Inspiration Mars documents is that it's much less likely to happen.  Instead of using existing rockets, the updated plan requires the SLS in 2017, and the initial SLS flight is scheduled for 2017.  SLS is could easily have a schedule slip due to budget, management, or technical issues.  The plan also requires commercial crew to be ready in 2017, and many of the Congressional interests on the space committees are hostile to that program.  It requires an accelerated development of an SLS upper stage, a radically-redesigned Orion capsule for Earth return, and a Cygnus-based habitat that also represents big changes from the current system.  It requires big changes in NASA's HSF plans, an influx of NASA funding to get many of these things done, a willingness by NASA to engage in such a partnership, changes to ISS plans to test parts of the system, and a big change in NASA's HSF risk posture.  I could see one or two of these things happening, but that is too many for me to believe are possible.

To be honest, I didn't think the original Inspiration Mars mission was going to happen, either.  However, I thought it was a really important contribution that Inspiration Mars is working on advances in ECLSS, an area that is underfunded at NASA because of government-wide budget pressures and the budgetary appetites of some big NASA programs.  This is still the case.  So my advise to Dennis Tito, (and given his excellent business and technical background I'm sure he's just been waiting for my advise on how to spend a big part of his fortune), is to not worry about a dash to implement the flashy mission.  Ultimately it will be more important to lay the foundation for such missions in the future.  Don't rely on NASA funding in these difficult budgetary times, but instead achieve what you can with what you have and the funding you can raise privately.

So if he is unalterably attached to using the 2017 Mars trajectory, try a much easier uncrewed flyby mission to Mars then.  Perhaps such a mission could include a Mars atmosphere sample return capability.  Perhaps it could demonstrate some of the technologies needed by the Inspiration Mars crewed flyby at some later date.

Alternately, focus on developing and testing in space the ECLSS capabilities that such a mission requires.  That is a major step that is not otherwise being worked on to a sufficient degree.  The technologies could be useful later regardless of whether they are used by private missions or NASA missions.  They also would be useful for other destinations, not just the Mars flyby.

Another possibility would be to concentrate on implementing the Cygnus-based habitat module or some other habitat module.  This could include the Inspiration Mars style ECLSS if he thinks he can also fund that, or a more traditional life support system.  Both would be big, high profile advances that would be inspirational.  They would also be useful for the ISS if tested there, useful to leverage the COTS cargo capabilities and make them more sustainable because of additional uses, and useful for a variety of possible exploration missions by government or private groups to various destinations.  If it can support a long deep space mission, it likely could also be a basis for a sort of mini space station even in LEO with extra radiation protection.  Another LEO space station is a key element that is currently missing (depending on Bigelow's future steps) in the current outlook for commercial crew.  Government systems could also interact with such a habitat-based mini space station module.  Of course the habitat module could be an essential part of an Inspiration Mars style mission in the future.

There are plenty of other worthy advances in space capabilities that Tito could support.  So I would recommend that, should things not work out for the big Inspiration Mars mission, that Tito not throw up his hands and walk away, but instead pick a more achievable advance and work to make that happen.

Sunday, November 17, 2013

SLS for Unaffordable Giant Robotic Missions: The More Things Don't Change, the More They Stay the Same

This past week rewarded us with a panel discussion Removing the Barriers to Deep Space Exploration.  The subject of the panel turned out to be the SLS heavy lift rocket and the Orion spacecraft.  Surprisingly, in spite of the title of the panel, the discussion was not about cancelling SLS and Orion to allow funding to go to the robotic precursor missions, exploration technology development, and affordable space infrastructure needed for actual deep space exploration that have largely been squashed by the SLS/Orion pair.  In fact, the discussion really didn't seem to be about barriers to deep space exploration at all.  Instead, it seemed like a snugglefest of love for the expensive capsule and even more wildly expensive rocket.  This may be a bit less surprising when one realizes that the speakers were a NASA official whose portfolio includes SLS and Orion and vice presidents of ATK, Lockheed Martin, Boeing, and Aerojet Rocketdyne, the main contractors that are building the SLS and Orion, and have been since 2005 (originally in the Ares/Orion variation).

One of the messages that the panelists sought to drive home was that SLS will be a wonderful launcher for ambitious robotic space missions such as NASA science missions and NRO spy satellites.  How generous for the SLS advocates to suggest that the NASA government rocket should compete with the U.S. launch industry.  Back in 2009 I wrote a post here called Constellation: Launching Science or Leeching Science based on the National Research Council's Launching Science: Science Opportunities Provided by NASA's Constellation System document evaluating the opportunities and dangers presented to NASA science by Constellation, mainly by the Ares V rocket.  I won't go into all of the details again, since the linked blog post and the report itself cover the ugly details, none of which have changed for the better.  The JWST is still absorbing a huge chunk of the NASA robotic science budget, that budget is still under great stress from general government-wide trends and the cost of the HLV and Orion, and still NASA and other space agencies seem to have crushing problems when developing large, ambitious space missions.

The danger is real: if it ever becomes operational and then allowed to compete with the U.S. launch industry with the backing of parochial Congressional interests, the SLS could cause serious harm to NASA science or even U.S. defense and intelligence capabilities by pushing them towards huge, unaffordable spacecraft beyond even JWST that they have no infrastructure to develop.  No wonder it's called a monster rocket.

Monday, January 21, 2013

Small Planetary Science Missions

The Vision for Space Exploration included a strong component of HSF robotic precursor missions and robotic science missions to exploration destinations.  Robotic precursor missions are a worthy topic, but today I'll discuss the status of robotic Planetary Science missions at NASA.  The status of the Mars program has been well-publicized, with NASA's withdrawal from ExoMars participation, near-term cuts to Mars mission funding, and the decision to initiate Mars-2020, a mission like the one that delivered the Mars Surface Laboratory Curiosity rover, but with an instrument suite that is yet to be determined.  The status of other NASA Planetary Science missions has not received nearly as much attention.  However, with recent and expected budget cuts, there will be no outer planets flagship missions, and the smaller Discovery and New Frontiers mission lines will be slowed.  Lunar Quest and Mars Scout small missions are already gone. Future Planetary Exploration gives some insight into the direction Discovery and New Frontiers are heading:

I picked up one key point in Monday’s meeting while listening to James Green, the head of NASA’s planetary science program.  In reviewing his program’s projected budget, his team believes that it can start two additional New Frontiers missions ($1B each) and a single Discovery mission ($500M) in the next ten years. The balance between the two programs is NASA's choice; for approximately the same funding it could select one New Frontiers and three Discovery instead.

The recent Planetary Science Decadal Survey anticipated 5 Discovery mission starts and 2 New Frontier mission starts over the course of a decade.  In its first decade, the Discovery program was able to start even more missions than that.  Now we could be looking at only a single competitively selected Discovery mission in a decade.  That's a going-out-of-business pace for Discovery, the backbone of NASA Planetary Science.

It is interesting that NASA has decided to implement the highest priority Flagship mission of the Decadal Survey.  However, Flagship missions are not the highest priority of the Survey:

It is also possible that the budget picture could turn out to be less favorable than the committee has assumed.  This could happen, for example, if the actual budget for solar system exploration is smaller than the projections the committee used.  If cuts to the program are necessary, the committee recommends that the first approach should be descoping or delaying Flagship missions.  Changes to the New Frontiers or Discovery programs should be considered only if adjustments to Flagship missions cannot solve the problem.  And high priority should be placed on preserving funding for research and analysis programs and for technology development.

The bold is the Survey's, as this is one of their key points.

The budget cuts are harming NASA Planetary Science, but ignoring the Decadal Survey and implementing a Flagship mission at the expense of most of the remnants of the Discovery mission line is not helpful.

Since we are already ignoring the Decadal Survey, I have a suggestion designed for these budget-challenged times.  That suggestion is to initiate a new line of "very small" Planetary Science missions.  With the possibility of a decade where Mars-2020 and 3 other missions are the only new starts, and the prospect of even more budget cuts to Planetary Science in the years ahead, something drastic is needed to keep the program and the associated science community in business once the missions that are currently in operation and under construction go silent.  Incoming data will be needed in future years.  Imagine if one of the rare future missions fails?  Something is needed for survival in the data-lean years, and I suggest that be a new line of competitively selected, low-cost, highly-focused Planetary Science missions.  These would be cost-capped at a level that is considerable lower than Discovery ($500M plus launch and possible NASA-furnished equipment in some cases).  Maybe the figure would be $200M, or maybe even $50M or much lower.  The goal would be to have frequent new mission starts, perhaps one per year or 2.  This mission line could be like NASA's new orbital Earth Ventures line (the line includes orbital, suborbital, and instrument mission series) or the Heliophysics and Astrophysics Explorers.  An example mission is CYGNSS.  The line would be for independent missions, and not for adding instruments to other organizations' planetary missions, since NASA already has such Missions of Opportunity.  In today's budget situation, implementing such a mission series would likely mean sacrificing one of the large missions, like one of the New Frontiers missions, which would certainly not be an easy choice to make.

One objection to such a proposal is that even though the cost of such missions would be lower, the corresponding reduction in science returned would be even greater.  Either mission risk would be increased unacceptably, or mission capability would decrease unacceptably.  Small missions may work for Astrophysics, Heliophysics, and Earth Science, but missions in those fields have a much easier time because they don't need to go to other planets, with all of the associated difficulties of communication bandwidth, long mission life, propulsion requirements, and more for flyby and orbiting planetary missions, let alone the challenges of landers and sample return.

One response to that objection is that Planetary Missions don't all have to go far.  Discovery shows this.  There could be "very remote" sensing missions like Kepler or NASA's proposed Near Earth Asteroid survey instrument that don't come close to their subjects.  There could be sample missions like Genesis that don't need to approach a distant planetary body.  A mission could wait for a NEO to approach us.  A lander could use a "less gentle landing" style like the ill-fated Deep Space 2 impactors.  Starting a line of such competitive procurements would likely generate many new low-cost mission ideas.

My main response to this argument, however, may take a bit of a leap of faith for the skeptical critic.  That response is that mission capabilities for small missions are increasing rapidly, and Planetary Science should not leave itself out of this trend.  Cubesats are becoming more powerful and a low-cost industry is growing around that standard.  Multiple cubes can be combined for more ambitious missions.  The Interplanetary Cubesat Workshop is evidence of the effort to increase the reach of Cubesats.  Planetary Resources is a company developing low-cost spacecraft capable of investigating asteroids.  An announcement is expected tomorrow for Deep Space Industries; we will have to wait to see what their vision is.  Multiple Google Lunar X PRIZE teams are striving to send missions to the lunar surface.  That is a largely private competition, but some teams may also be interested in having a government customer.  NASA has a space technology program that may be interested in demonstrating technologies like aerocapture or solar electric propulsion at other planets.  Perhaps some sort of collaboration could occur with that organization on a small Planetary Science mission.  Many other small spacecraft efforts are in progress for Earth environment observation, military, technology development, and other purposes, perhaps representing a combined wave of efforts unlike any that has come before.  NASA Planetary Science can ride this wave, and at the same time help it grow, or it can ignore it and struggle, perhaps successfully, to scrape up the funding for each one of the small remaining handful of large missions it now expects.

Friday, June 22, 2012

B612 Foundation Makes Last Week's Post Obsolete

Here's an update to my status of robotic precursors post from last week:

Asteroid experts plan privately funded Sentinel Space Telescope - Cosmic Log

Here is the B612 Foundation Media Advisory on a press conference to be held on June 28 on the first privately funded deep space mission.


Wednesday, June 13, 2012

Robotic Precursor Prospects: It Was the Best of Times, It Was the Worst of Times

As most readers are surely aware, NASA's effort to return to the Moon in recent years included the robotic precursor missions Lunar Reconnaissance Orbiter and LCROSS.  These modern robotic pathfinders for HSF succeeded, but the costly Ares rockets and Orion capsule forced the elimination of the longer-term line of robotic precursor missions that was such a crucial part of the Vision for Space Exploration.  NASA's proposed FY2011 change in direction called for the revival of the robotic precursor line, but this time it would scout multiple destinations, such as the Moon, NEOs, Mars, and the Martian moons, for resources and hazards to astronauts, as well as to demonstrate technologies like ISRU at those destinations.  In the compromise between the Administration and Congress that allowed NASA to start the commercial crew program and to restore some technology development funding lost during the Constellation years while forcing the agency to develop the SLS and MPCV, the robotic precursor mission line was first scaled back considerably, and then lost altogether.  With the prospect of budget overruns on the big projects and general downward pressure on NASA's budget, it doesn't look easy to revive the robotic precursors.

It is possible for NASA's Planetary Science program to do some robotic precursor work as a by-product of its robotic science missions, but NASA's Planetary Science budget is being cut.  In this case the expensive JWST is a major cause of the budget pressure, but the expense of the proposed Planetary Science Flagship missions is not helping.

Could the situation for robotic precursor missions be any worse?

There is no doubt about it, the vital concept of robotic precursor missions for HSF has fallen on hard times.  Robotic precursor missions can be quite affordable and can accomplish a lot, but it's not easy for them to thrive at NASA when the agency budget is cut while expensive NASA projects with strong political backing enjoy cost overruns and delays.

Having set this rather unpleasant stage, I'd like to offer some hope for robotic precursors.  I don't think we will see a fleet of NASA robotic precursor missions fanning out across the inner solar system like we might have hoped during NASA's FY11 budget proposal, or making tracks in the lunar surface like we might have expected during the early days of the Vision for Space Exploration. It's likely that many of the robotic precursor possibilities I'll mention will not come to fruition, but we still can reasonably expect to see some progress.  Here are some possible sources of such HSF robotic precursor progress: 

Planetary Resources - There has been a lot of discussion of the long-term goal of Planetary Resources to mine asteroids, and also of its shorter-term prospects in selling low-cost spacecraft for astronomy and Earth imaging.  However, I haven't seen nearly has much on the role this company could play in the robotic precursor field.  Consider NASA's August 2010 Exploration Precursor Robotic Missions (xPRM) Point of Departure Plans (PDF) presentation, which focused on NEO robotic precursor missions.  This set of missions included a NEO Telescopic Survey to identify appropriate NEOs for HSF missions.  It also included several options for NEO Rendezvous missions to more fully characterize potential targets, from one spacecraft comparable to a NASA Discovery mission to study a single NEO in detail to a set of 3 or 4 small spacecraft to study several potential HSF destinations in less detail.  These NASA plans don't appear to have much chance of happening in the current political and budget environment, but consider how Planetary Resources might achieve similar goals, either in the course of their own space resource assessment and development plans or by offering a low-cost way for NASA to achieve some of its robotic precursor goals should a funding wedge appear.  The first Planetary Resources spacecraft is a Leo Space Telescope that can search for NEOs.  The second Planetary Resources spacecraft planned is the Interceptor that could approach, study, and possible "intercept" Earth-crossing NEOs.  The third generation is the Rendezvous Prospector, which could rendezvous with NEOs that are more difficult to reach and require more capable communication links.  It's not too difficult to see how these generations of spacecraft could fulfill some of the robotic precursor ambitions that NASA had for NEOs, although depending on the circumstances the resulting data might not be available to certain organizations that might need it. 

Google Lunar X PRIZE - The Google Lunar X PRIZE is a $30M competition intended to encourage private groups to develop mobile lunar landers.  There are dozens of Google Lunar X PRIZE teams with varying goals, prospects for winning the competition, and intent to do work that would return significant robotic precursor data.  I won't describe all of the teams here, but instead will just give one example of a prominent team with robotic precursor ambitions.  Astrobotic intends to send an 80 kg rover, Red Rover, near the lunar equator to win the prize and to deploy 30 kg of science instruments.  It then plans to send a 150 kg rover, Polaris, with 80 kg of instruments to one of the lunar pole regions to prospect for water.  The intent is to continue with a series of missions. 

NASA's Mars Upheaval - I have mixed feelings about the current changes in NASA's Planetary Science portfolio, and in particular with its Mars missions.  On the one hand, I don't think Planetary Science is the right place for the budget ax to fall, and I don't like to see an affordable mission like the 2016 ExoMars Trace Gas Orbiter mission abandoned (at least as far as the U.S. is concerned).  On the other hand, I don't think either NASA's original Mars Sample Return plan or the next-in-line Flagship mission to Europa were affordable, and the possibility of developing more affordable missions with intentional HSF participation in the robotic precursor sense is welcome.  It's hard to predict what the outcome of all of this will be, and it's probably a fair bet to guess that it won't end well.  In the meantime, we can see a step in the process right now at the Concepts and Approaches for Mars Exploration conference being held from June 12-14 at the Lunar and Planetary Institute.  Here are some sample abstracts (all PDFs) that show some of the robotic precursor possibilities that just might emerge from the current chaos:

ICE DRAGON: A MISSION TO ADDRESS SCIENCE AND HUMAN EXPLORATION OBJECTIVES ON MARS - We present a mission concept where a SpaceX Dragon capsule lands a payload on Mars that samples ground ice to search for evidence of life, assess hazards to future human missions, and demonstrate use of Martian resources.

HUMAN EXPLORATION AND PRECURSORS: IN SITU RESOURCE UTILIZATION - This is a whole track with 9 abstracts dealing with Mars robotic precursors and ISRU.

PHOBOS AND DEIMOS SAMPLE COLLECTION & PROSPECTING MISSIONS FOR SCIENCE AND ISRU

Radiation Dosimetry From a Nanosat Lander System for Mars 

Existing NASA Robotic Science Missions - Robotic science missions can accomplish HSF robotic precursor goals even though that is not really their purpose.  NASA currently has a number of robotic science missions at potential early HSF destinations.  Mars Odyssey and Mars Reconnaissance Orbiter are in orbit around Mars, as are NASA instruments on Europe's Mars Express.  The Opportunity rover still operates on the Martian surface.  Dawn is transitioning from its investigation of asteroid Vesta to soon begin its voyage to Ceres.  The GRAIL spacecraft are in orbit around the Moon, and their gravity map can be expected to help with future lunar landings.  The re-purposed ARTEMIS spacecraft from the THEMIS heliophysics mission are now doing lunar science from Earth-Moon Lagrange points.  The best example of all is probably the Lunar Reconnaissance Orbiter, which continues to gather robotic precursor data even though it is now managed as a science mission.  This just covers NASA missions, but there are international robotic science missions with robotic precursor potential, too.

Do these existing science missions offer enough robotic precursor potential for you?  Probably not, but it could be a lot worse.  Consider the 1980's and their huge list of robotic precursor missions and science missions with robotic precursor by-products.  Yes, things can get worse than they are today. 

Selected Future NASA Robotic Science Missions - Several NASA robotic science missions under development have the potential to return valuable robotic precursor information.  LADEE will study lunar dust and demonstrate laser communication from lunar orbit, both of which have implications for human lunar missions.  MAVEN will study the Martian upper atmosphere.  Osiris-REx will study and return a sample from carbonaceous asteroid 1999 RQ36.  The "RI" in "Osiris" stands for "resource identification", a clear nod to robotic precursor potential in this science mission.

Potential Future NASA Robotic Science Missions - A number of potential future NASA missions (other than those of the Mars-specific mission line I already discussed) could provide robotic precursor information.  The selection for the next round in the NASA Discovery program is scheduled to be made soon.  One of the three contenders is InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport), a Mars Geophysics lander mission.  The Planetary Science Decadal Survey recommended that NASA consider 7 missions for 2 selections over the course of the next decade (2013-2022).  These missions include Lunar South Pole-Aitken Basin Sample Return (similar to the MoonRise proposal from the final round of the last New Frontiers selection), Trojan Tour and Rendezvous (which unfortunately would take a very long time to reach the asteroids near Jupiter's Lagrange points), and Lunar Geophysical Network.

Unfortunately, proposed Planetary Science budget reductions don't just affect the Flagship proposals as has been widely reported.  These reductions also greatly reduce the number of Discovery and New Frontiers missions that would be flown over the course of the next decade. 

Mars Science Laboratory - I didn't mention MSL as either an existing NASA mission or a mission under development since it's no longer under development, but not yet in its primary operational phase.  Curiosity will land on Mars soon.  This is a major, highly capable Mars Science rover that can be expected to deliver useful robotic precursor knowledge if it succeeds in reaching operational status.  There will be multiple sources of such knowledge.  For example, the MEDLI (MSL Entry, Descent, and Landing Instrumentation Suite) technology demonstration on the lander heat shield will gather data about the Martian atmosphere and the performance of the landing hardware as it works.  This will enable improved landing systems in the future.  The RAD (Radiation Assessment Detector) is a genuine robotic precursor instrument whose main purpose is to assess radiation hazards for future astronauts on Mars.

NEOCam - In addition to selecting InSight as 1 of 3 competitors for NASA's next Discovery mission, 3 Planetary Science technology development efforts were selected by Discovery.  One of these is NEOCam (PDF), an IR space telescope intended to search for Near Earth Objects.  This would be useful as a robotic precursor tool, since our catalog of NEOs that are suitable destinations for early HSF missions is small.

Summary

Will all of the possible future missions I mentioned with robotic precursor potential happen?  I would be surprised if most of them do.  Will the NASA Science missions deliver significant robotic precursor data?  That will vary on a mission by mission basis - some can be expected to deliver significant robotic precursor data, and the robotic precursor benefit of others will likely be tenuous at best.  The Administration and NASA should make a stronger stand for funding a dedicated line of robotic precursor missions to the Moon, NEOs, Mars and its moons.  Although a large budget would be helpful, to be productive this line would not need the type budget the Administration originally proposed for robotic precursors if it used focused, small, low-cost missions, instrument/experiment rides with other missions (such as robotic science missions), and/or lean commercial procurement strategies (data purchase, etc).

Saturday, January 14, 2012

Space Bartering

Aviation Week and Space Technology reports that ESA and NASA are considering using ATV technology for the Orion spacecraft's service module in a barter agreement involving ISS services.  One could imagine such a barter agreement being extended in the future, as perhaps ESA astronauts get rides on Orion launched by SLS in exchange for additional service modules.  Theoretically, such an arrangement could lower the astounding cost of Orion to the U.S. or shorten the development schedule (as the SM is currently given lower priority than the capsule). However, given that Orion is many years into its development, design changes caused by a new SM could affect the whole spacecraft, and that the international barter arrangement would introduce a whole new level of managerial complexity, it's not immediately clear that significant savings would really be forthcoming, especially during the rather long development phase.  That is exactly what NASA and ESA are trying to find out.

Could a different NASA-ESA barter arrangement be made that includes the following characteristics?
  • includes ESA in NASA's exploration plans
  • doesn't upset an applecart that has been designed for many years
  • adds value to NASA's plans
  • involves distinct elements to reduce managerial and political complexity
  • uses ESA's strengths
  • does not damage U.S. interests, such as subsidizing European competition with U.S. commercial space
  • involves work that ESA would want to do (fitting their long-term goals, using their industry, etc)
During the negotiations between the White House and Congress on NASA's exploration plans, a lot of important work was dropped to fund SLS and Orion.  For example, even under Constellation, we developed the robotic precursor missions LRO and LCROSS.  The Administration's proposal revived the robotic precursor line to include numerous robotic precursor missions to the Moon, NEOs, Mars, and its moons.  Congress was not interested in robotic precursor missions, and the robotic precursor line was gone before it really started.  Would NASA be interested in bartering for an ESA robotic precursor mission, or a series of such missions?  Such missions could be ESA-only, or they could perhaps host some U.S. instruments and experiments if funding can be found for those.  NASA might get rides for its instruments and experiments in the barter arrangement, and would at least get essential data from the deal.

If we are planning to return to the Moon, robotic precursor missions could assess lunar resources, do ISRU experiments, and so on.  Missions might be similar to the roving Lunar Polar Volatiles Explorer, a static lander with experiments and a Mars Pathfinder sized lunar rover to assess resources as considered by NASA's robotic precursor team, or the Lunar South Pole-Aitken Basin Sample Return mission (which is also a high priority on NASA's Planetary Science side).

If we are planning to go to NEOs during some of the steps on the Flexible Path to Mars, robotic precursor missions could broadly search for suitable candidate NEOs using instruments like NEOCAM, do NEO flyby missions to assess basic characteristics of multiple NEOs, or go to a particularly interesting NEO candidate to do detailed resource investigations, ISRU experiments, and search for hazards (such as small satellite asteroids). 

Some robotic precursor missions might involve NASA-ESA collaboration in a single spacecraft just as suggested with the Orion barter deal with an ESA SM.  Planetary Science has a lot of successful experience with this sort of collaboration, where instruments or even entire landers are hosted on a spacecraft from another country.  (This is not to suggest that the Orion barter arrangement would not work or international collaboration hasn't happened on non-Planetary missions - e.g. ISS and Orbital's Antares/Cygnus).

Similarly, exploration technology development is getting limited funding.  The earlier Administration proposal to demonstrate highly capable solar electric propulsion, propellant depots, AR&D tugs, inflatable modules, closed-loop life support, and aerocapture during the start of a series of well-funded exploration technology demonstration missions while also funding technology development in numerous areas like ISRU, landing, telerobotics, fission power systems, and even more capable electric propulsion have been scaled back almost beyond recognition.  Could ESA contribute to implementing some of these or similar exploration technology demonstration missions in a way that would give NASA the data that it needs, and perhaps even give NASA a ride to demonstrate some of the exploration technologies that NASA can afford to develop even now?  For example, could ESA do an aerocapture demonstration mission at Mars, or even at Earth, giving NASA access to the data?  Could ESA collaborate with NASA and U.S. commercial space to demonstrate an inflatable habitat module where ESA provides some of the internal and external components of the system, or would such an arrangement have similar potential disadvantages to the Orion/ESA SM barter?  The long-term interest for ESA might be in participation by ESA or European industry when such modules are used as habitats in exploration missions, or when they are used commercial space habitats.

The point I'm trying to make is that there are a number of important exploration jobs that currently aren't being done that could be more productive subjects of NASA-ESA barter arrangements than the Orion SM.  Suggestions on what those might be are welcome.

Thursday, December 22, 2011

A Vital Cislunar Space Application: Satellite Servicing

In my discussion of the Flexible Path to the Moon, I emphasized the importance of cislunar space.  My view is that developing infrastructure and capabilities in cislunar space is crucial to sustainable and affordable astronaut exploration to more distant destinations like the lunar surface, NEAs, and Mars, and is also vital to enabling exploration efforts to deliver near-term benefits to the taxpayer.  A number of articles have recently appeared that highlight the promise of cislunar space, such as Accelerating the future: human achievements beyond LEO within a decade (The Space Review), Exploration Gateway Platform hosting Reusable Lunar Lander proposed (NASAspaceflight.com), and Phase II of “Asteroid Next” missions: Proving Grounds for future crewed Mars missions (also NASAspaceflight.com).  These have generated considerable interest and discussion, and it would be fun to add my voice to those discussions.

But I'm not going to do that.

Instead, I'd like to focus on a part of the Conference Report for H.R. 2112, the bill that funds NASA for the next fiscal year.  The following excerpt is from the report's Space Technology section:

Satellite servicing.—The conference agreement provides no less than $25,000,000 for satellite servicing activities. This funding will contribute to the planned competitive satellite servicing demonstration mission and shall be managed by the Human Exploration and Operations (HEO) Mission Directorate.

This $25M (at least) is part of the $575M for Space Technology. 

The following excerpt is from the report's Space Operations section:

Satellite servicing.—The conference agreement includes $50,000,000 from Space Operations to continue satellite servicing activities. These funds are in addition to $25,000,000 for satellite servicing in the Space Technology account. The HEO Mission Directorate shall continue to be responsible for the overall direction and management of all agency satellite servicing activities, which are undertaken as a joint project of the HEO, Space Technology and Science mission directorates. Satellite servicing activities shall include mission architecture design, robotic system development, autonomous rendezvous and capture sensor testing, fluid transfer demonstrations and spacecraft design.

Funds are to be used to continue work on a competitive project to develop, in collaboration with a U.S. commercial partner, a satellite servicing mission capable of operating in geosynchronous Earth orbit. The goal for such a mission is to achieve an on-orbit servicing of an observatory-class government satellite by 2016. Any U.S. commercial partner should be willing to invest its own resources in this mission, as it is intended to foster the creation of an ongoing commercial capability that could meet the needs of NASA, other Federal agencies, the commercial satellite sector and the scientific community.

The funds are for a satellite servicing mission involving NASA and a commercial partner with skin in the game operating in geosynchronous orbit.  Demonstration of such a commercial capability could be an important step in opening new robotic commercial satellite servicing markets in cislunar space, and could even lead later to development of human satellite servicing markets there.  Creation of such self-sustaining economic capabilities represents an important milestone in the development of cislunar space, and could be an important step in enabling sustainable exploration and development of more difficult destinations like the lunar surface and NEAs.

The most immediate activity of the NASA Satellite Servicing Capabilities Office is the Robotic Refueling Mission on the International Space Station.  This mission demonstrates robotic technologies to refuel, repair, and otherwise service satellites using various tools.  The office is also investigating a Robotic Servicing Mission.  This would be a robotic mission to demonstrate actual servicing for one or more GEO satellites. 

NASA has released an RFI for development of an on-orbit robotic servicing capability for spacecraft.  In this RFI, NASA shows its interest in a public-private partnership where it uses its satellite servicing capabilities and experience with a commercial partner:

NASA does not intend to establish a Government operated on-orbit satellite servicing capacity but rather to foster the creation of a domestic capability which may meet both future Government and non-government needs. Satellite servicing capabilities may include satellite recovery, repair, relocation, refueling, inspection, subsystem or component replacement, or other services that extend the life or capabilities of on-orbit assets.

The detailed RFI (PDF) gives several examples of the types of partnerships that NASA might be interested in pursuing with private industry.  The RFI makes it clear that the envisioned mission is a robotic one to GEO (as opposed, for example, to a mission where GEO satellites are delivered to and from servicing robots and/or astronauts in LEO), even though Congress's direction is that NASA's HEO Mission Directorate will be in charge of NASA's overall satellite servicing effort.  The RFI lists several contributions that NASA might make to the effort, such as satellite servicing patents, tools for repair, refueling, and other servicing jobs, autonomous rendezvous capability, sensors, test labs, operations support, computer resources, and more.

The RFI suggests several potential types of public-private partnerships.  In one partnership model, the commercial partner owns and is responsible for the servicing hardware while the government provides some of the contributions just described as well as an initial satellite to service.  In another model, the government pays a fixed price for commercial services, with both partners contributing hardware and support.  The commercial partner could rent the servicing vehicle for additional servicing missions beyond the government satellites.  In a third model, the commercial partner would be responsible for the entire system, and NASA would not identify a government satellite to service, but could provide intellectual property to the commercial partner.  Other models can be considered.

Several questions and responses (PDF) related to the RFI have also been published.  Some of these deal with foreign participation.  This is not surprising, since MDA is interested in and concerned about the NASA satellite servicing mission. 

Meanwhile, the First Community Workshop on Assessing Capabilities for Human Operations in Cis-Lunar Space: What's Possible Now? includes a presentation on a Manned GEO Servicing Study (PDF) involving NASA and DARPA.  Different satellite servicing missions by astronauts in GEO that would be useful in and of themselves while preparing NASA for future, more distant exploration missions are presented.  Missions could include habitat nodes and tugs to move satellites.  

DARPA has also presented the PHOENIX workshops on a potential satellite servicing program:

The goal of the Phoenix program is to develop and demonstrate technologies to cooperatively harvest and re-use valuable components from retired, nonworking satellites in GEO ...

 There are multiple components in the Phoenix architecture.  Nanosatellites would be launched as secondary payloads.  A satellite servicing component would robotically attach the nanosatellites to an antenna of a dead satellite, enabling the large antenna to be reused.  The nanosatellites are delivered in a new PODS nanosatellite delivery module.  This PODS delivery mechanism meets with the satellite servicing component which can then use the nanosatellites and tools in the PODS as a sort of tool chest.

Like robotic precursor missions to the Moon, NEAs, or Mars, a commercial GEO robotic satellite servicing mission can help set the stage for more ambitious future astronaut servicing missions in the same type of location.  A commercial robotic satellite servicing mission done in partnership with NASA can also strengthen the U.S. commercial spaceflight industry, much like NASA's current approach to send cargo and later crew to the ISS using commercial services.  A commercial robotic satellite servicing mission can demonstrate some of the technologies and capabilities needed by NASA to productively and safely send astronauts to more distant destinations like Lagrange points, the lunar surface, NEAs, and Mars and its moons.  This is especially true of missions that leverage robotic capabilities like telerobotics.  Finally, a commercial GEO robotic satellite servicing mission that involves satellite refueling can develop new markets for fuel that could later come from locations like the lunar surface, thus creating an opportunity for the type of exploration and development using ISRU that can create a strong space economy.

For more information:

On-Orbit Satellite Servicing Study - Project Report - comprehensive 2010 NASA satellite servicing workshop report, including a history of satellite servicing and several potential servicing missions from basic robotic satellite servicing to astronaut assembly and maintenance of large observatories

SSCO - NASA Satellite Servicing Capabilities Office

NASA_SatServ - Twitter account for the NASA Satellite Servicing Capabilities Office

The Future of On-Orbit Satellite Servicing - SpaceRef Forum (article from the September 2011 Space Quarterly (PDF)) - This gives a good overview of the history and recent state of satellite servicing.

Robot Surgeon Tech Aims to Fix NASA Satellites - Space.com

Medical Robotics Experts Help Advance NASA’s ‘Satellite Surgery’ Project - Johns Hopkins University

Frank Cepollina, Deputy Associate Director, Space Servicing Capabilities Office, NASA Goddard Space Flight Center - Space News - This covers the Robotic Refueling Mission, a satellite servicing test on Earth, and the potential servicing mission in GEO.

NASA Selects First Payloads For Upcoming Reduced-Gravity Flights - NASA - This includes a Zero-G flight for the Autonomous Robotic Capture payload, similar to the Approach, Rendezvous and Capture Demonstration Cepollina mentioned in the previous article.

Thursday, January 13, 2011

A Puzzle to Distract Us From HEFTy Price Tags

With all of the news about the Human Space Exploration Framework Summary and Preliminary Report Regarding NASA’s Space Launch System and Multi-Purpose Crew Vehicle, I thought I'd write a few pages about them.  Then, I changed my mind and decided to ignore them.  I wanted to have some fun instead, and there is nothing fun about unaffordable HEFT reference missions and unneeded rockets designed by a handful of well-placed members of Congress.

I like puzzles, so I made a word search puzzle at puzzle-maker.com to take my mind off the doom and gloom.

I'm not sure, but I may not have completely succeeded in taking my mind off of the train wreck, though:

C  V  N  S  A  S  E  E
A  L  O  B  L  C  T  H
N  H  I  W  L  S  U  E
C  M  R  R  A  O  K  F
E  P  O  W  T  K  A  T
L  C  Q  S  E  R  A  T
T  V  C  O  S  T  L  Y
E  R  I  M  G  A  U  Q
ares late
bloat mpcv
cancel orion
costly quagmire
esas sls
heft waste
HLV

Friday, January 07, 2011

Compelling Planetary Science Missions: What Comes After the Top Five?

This completes 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 presents my point of view of the type of planetary science accomplishments possible through the next Decade's work beyond what I found to be the 5 most compelling missions from the Decadal Survey list.

First, let's review the missions I selected, and their estimated FY15 costs with reserves:
  • Lunar Polar Volatiles Explorer - long-range rover with drill - $1,132M
  • Enceladus Orbiter - Saturn tour followed by Enceladus orbit - $1,613M
  • Mars Polar Climate Mission (2 selections from Decadal Survey options) - climate and weather orbiter and polar subsurface sampler lander - $613M + $860M = 1,473M
  • Mars Geophysical Network - 2 geophysical landers - $1,015M
  • Lunar Geophysical Network - 4 geophysical landers - $903M
This selection is consistent with this blog's theme of restoring the Vision for Space Exploration that was, with some exceptions like LRO and LCROSS, lost in 2005 with the onset of Constellation.  It covers the "Moon, Mars, and beyond" idea almost a bit too literally, since (in my view) Planetary Science should "lean a bit" in this direction while still being driven by science priorities, while a well-funded Robotic Precursor line on the astronaut exploration side should be the main robotic support line for the VSE's robotic needs.  The Lunar Polar Volatiles Explorer is a particularly important mission in support of the VSE goals, whether funded through Planetary Science or Robotic Precursors.  The Enceladus orbiter doesn't quite fit the specific outer planet wording from the Outer Planets section of the VSE, which emphasizes Jupiter's moons and then Titan, but I think it could be justified in the context of the VSE given knowledge gained by Cassini since the VSE was developed.

The total estimated cost in FY15 dollars of these 5 missions (including 8 landers and 2 orbiters) is in the ballpark of $6B.  I could assume the cost would be less, since the missions include significant reserves, and some have substantial heritage.  I could also assume partnerships lower the cost to NASA Planetary Science (e.g.: partnerships with international space agencies, synergy with NASA robotic precursor or technology development lines, commercial participation), but I'll instead assume that such partnerships tend to add capabilities rather than lower cost.  The budget for the Enceladus Orbiter includes operations spending that happens far past the timeframe of the Decadal Survey, so I might be able to overlook some of the budget needs of that mission.  However, I'm more comfortable leaving the estimate for the 5 missions at $6B.

I don't know what the NASA Planetary Science new mission budget will be for the next decade, but let's suppose it's $11.5B in FY15 dollars.  That would leave some money for other areas like Planetary Science technology development, instruments, research, operating long-duration missions, data systems, and so on.  I'll ignore issues like missions whose funding spans multiple Survey decades.  With those simplifying assumptions, with $6B or so for the top 5 missions, we'd still have a healthy $5.5B for other missions.

It would have been easy to have chosen 5 missions that together cost far more than $6B, since the Decadal Survey list concentrates on New Frontiers and Flagship missions (i.e. ambitious but expensive ones).  For example, here are the listed FY15 costs for 3 particularly capable, long-sought-after, and undeniably compelling missions that very well might be emphasized by the Decadal Survey:
  • Jupiter Europa Orbiter - $3,897M ($1,200M of this is reserves)
  • Mars 2018 MAX-C Caching Rover - $2,196M (and this requires 2 more large missions before the biggest reward - Mars sample return - happens)
  • Titan Saturn System Mission - $3,456M
As you can see, if we go with those 3 missions, and assume a total Planetary Science budget of $11.5B for missions, we aren't left with much else for the other 2 of the top-5 missions, let alone other missions.  The Mars 2018 MAX-C mission assumes an earlier ESA/NASA ExoMars mission for telecommunications, so we have even less room for flexibility if we select these 3 missions.  Those would be 3 great missions, but I don't think I'd want Planetary Science to be limited almost entirely to these 3.  I'd also consider the impact to Planetary Science if any of these 3 suffered serious cost overruns or a major technical failure, considering how many eggs would be in so few baskets.

Since I happen to have picked some of the less-expensive missions from the Survey list, though, I now have a chance to provide some depth to what would be, if left to stand by itself, a fairly unbalanced set of missions in my top 5.  I seem to have emphasized Mars, the Moon, and geophysical networks at the cost of sample return, Venus, small bodies, and other priorities.  Can that be fixed?  What should we do with the "leftover" mission funding?

The first thing I'd do with that extra $5.5B is establish a funding block (for the sake of discussion, let's say $1B over the decade) for "frequent, very low cost missions".  This would be in addition to existing areas like flights of opportunity for instruments on non-NASA missions.  This might sound like the Discovery line of missions, but for various reasons, the Discovery line is getting a bit expensive.  The FY10 Discovery mission limit used in the Survey studies is $580M for FY2010; it's assumed to be $666M in FY2015.  That includes $155M (FY10) or $178M (FY15) for an assumed Atlas V 401 launch.  The new mission line that I'm proposing would be for lower cost Planetary Science missions than that.  You might think of some of the early Discovery missions, the new "Venture Class" Earth observation missions, or astrophysics and heliophysics Explorer, MIDEX, and SMEX missions.  This line would seek to take advantage of opportunities like
  • potential lower-cost launchers, such as the Falcon 1e, Falcon 9, and Taurus II
  • potential increased availability of secondary payload slots on launchers
  • commercial data purchases, similar to NASA's Innovative Lunar Demonstrations Data contracts, but for planetary science data rather than engineering data
  • other cooperative arrangements with non-NASA partners such as commercial vendors
  • cooperative missions with other NASA areas like Space Technology, Exploration Technology Development and Demonstration, and Robotic Precursors, or even entire small space missions whose main purpose is to demonstrate products of the Planetary Science technology development budget
  • focused, low-cost mission approaches (for example, penetrators like the Deep Space 2 Mars technology demonstrators)
  • favorable trends in the small satellite field
Such missions would probably tend to go to some of the Planetary Science destinations that are easier to reach quickly, such as the Moon, Venus, Mars, comets, and NEOs.  If that happens, they could fill in some of the gaps of my original 5 mission list (Venus, NEOs, comets) while strengthening the Moon and Mars focus of that list.

If we used $1B for that, we would have $4.5B left.  I think we should have at least 3 Discovery missions (4 if you count the Mars Scout-like Mars Climate Orbiter I selected in the most compelling missions as a Discovery mission).  There are a lot of gaps left in my mission choices that these Discovery missions could fill in.  For example, even with my predisposition to favor missions with "astronaut robotic precursor" potential, I didn't select a single Near Earth object mission, even though Near Earth objects are often discussed as the first beyond-LEO destination in NASA's new Flexible Path plan for astronaut missions.  (Actually the first beyond-LEO mission destination in that plan is cislunar space - possibly lunar orbit or an Earth-Moon Lagrange point - but those early beyond-LEO missions are often overlooked when the new plans are discussed).

Why didn't I select any Near-Earth asteroid planetary science missions?  Well, for one thing, there weren't any on the Decadal Survey list.  I didn't allow the current batch of New Frontiers missions, including the Near-Earth asteroid sample return mission OSIRIS-REX, in my selection.  The Decadal Survey studies include an analysis of "Near Earth Asteroid Trajectory Opportunities", but I didn't consider that to be an actual mission.  The list also includes an affordable "Trojan Tour Concept", but Trojan asteroids are by definition the "cloud" estimated to include hundreds of thousands of objects (if we only count those greater than 1 km in diameter) around the L4 and L5 Jupiter-Sun Lagrange points.  Those are not candidates for early astronaut exploration missions, and in fact, it could be a couple of decades before the Trojan Tour robotic mission would get there if it was selected - with 1 decade for the actual trip.  Nevertheless, the Trojan Tour is affordable and would cover a set of bodies that has never been visited before, so it is certainly worth consideration.  There is also an affordable Chiron Orbiter mission in the Decadal Survey list, but this would take even longer to launch and to reach its destination.

So, with the most compelling missions I've selected, we probably have a coverage gap in the area of Near Earth objects, or at least primitive bodies in general.  One or two Discovery missions to fill that gap might be in order.  We also have coverage gaps at Venus and Jupiter.  So, if we add 3 Discovery missions, we might be able to let the Discovery mission selection process fill some of the gaps I left with my top 5 selections.

If we assume the Discovery missions cost $700M each, that leaves us with $2.4B.  What should we do with that?  There are a number of interesting possibilities:
  • Upgrade the Enceladus Orbiter to a full-blown Titan Saturn System mission, or switch it to the Jupiter Europa Orbiter after all.  This would make a lot of the planetary science community and international partners happy, although I would still worry about mission cost until data starts coming in (upon which time I would undoubtably forget cost).
  • Fly the Mars 2018 MAX-C Rover after all.  This would make a different, but also big, part of the planetary science community and international partners happy.  With $2.4B available and a mission estimate of about $2.2B, there would be a little bit of slack to also cover NASA's contributions to the earlier Mars Trace Gas mission (e.g.: the rocket, instrumentation, telecommunications), but one of the Discovery missions might need to be traded or postponed to fully cover that.  Because of the amount of planning and interconnected missions involved, this selection might make a great deal of sense, in spite of my serious worries about mission cost.
  • Fly a variant of the Venus Climate Mission (which barely missed my 6th-place spot).  The basic mission should allow room for anther Discovery mission, which is the approach I would tend to take.  Alternately, the Venus Climate Mission could fill up the $2.4B by taking on some of the capabilities of the more ambitious Venus Climate Flagship reference mission.
  • Assuming the current New Frontiers selection picks one out of MoonRise (lunar sample return), SAGE (Venus lander), and OSIRIS-Rex (Near-Earth asteroid sample return), we should be able to afford to fly the other 2 with the leftover $2.4B.  I find this to be a particularly attractive option, since these missions should be in a more well-developed state than some of the others in the Decadal Survey list, since they address sample return (which I've completely skipped in my selections), since they have significant "robotic precursor" and "exploration technology demonstration cooperation" potential, and since they partially address some of the content that I lost by letting the Venus Climate Mission slip into 6th place on my list.
  • Fly 3 more Discovery missions, giving a total of 6 - a good decade for this class of missions.  I tend to think of Discovery missions as the "meat and potatoes" of Planetary Science, so I'd seriously consider this option.  One of those Discovery missions (or a mission with similar cost but selected and managed differently) might be a second Lunar Polar Volatiles Explorer, just like the first one but at another lunar location (e.g.: the other pole).
  • All sorts of other possibilities.
We can't do everything, but picking one of these would at least fill in some of the gaps that I've left with my original 5 selections.

Sunday, January 02, 2011

Compelling Planetary Science Missions: Showdown Between Lunar Geophysical Network and Venus Climate Orbiter

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 presents my personal selection for the 5th and last most compelling mission from the list.

I'd like to select a mission that fits well with one of the Mars missions I selected as my 3rd and 4th most compelling mission: a 2-part Mars Climate mission and a Mars Geophysical Network.  The obvious choices to me were the Venus Climate Mission and the Lunar Geophysical Network.  First, let me described these 2 contenders for the 5th spot as presented by the Decadal Survey mission concept studies.

The Lunar Geophysical Network includes 4 similar landers that would arrive at different locations on the Moon.  These landers would have goals that are not very different from those of the Mars Geophysical Network.  They would be expected to determine information about the lunar crust, mantle layers, and core (e.g.: size, state, composition, temperature), assess lunar heat flow, and measure moonquakes.  Each lander would include a seismometer, magnetometers, electric field sensors, a Langmuir probe, retroreflectors, and a heat flow sensor.  As with the Mars Geophysical Network seismometers, the 4 seismometers on 4 landers in the lunar network concept would work together simultaneously to produce results that are much more useful than measurements from a single seismometer.  The heat flow sensor would be deployed under the regolith up to 3 meters, possibly delivered by a "mole".  The retroreflectors are targets for Earth-based lasers that precisely measure the distance from the laser to the retroreflector. 

The lunar day/night cycle encourages use of ASRGs, which in turn encourages use of an Atlas V variant for launch.  The Falcon 9 is not certified for launch of ASRGs, but a less capable mission variant is depicted using Falcon 9 to launch 2 solar-powered landers.  There is a tradeoff between expensive ASRGs (and related certification) and heavy, less capable solar power and batteries.  My mission selection for the top 4 most compelling missions is already ASRG-heavy, so the ASRG option might be problematic in that context.

Clive Neal presents more justification for a mission like this one in The Rationale for Deployment of a Long-Lived Geophysical Network on the Moon.

One of the nice things about this proposal is that it can start to produce results quickly.  The mission could launch and begin to return data in FY16.  Compare that to my second most compelling mission choice, the Enceladus Orbiter, which might launch in the mid-2020's and arrive at Saturn in the 2030's.

Another attraction compared to many other missions in the Decadal Survey list is the estimated cost, $903M in FY15 dollars with reserves included.

On the other hand, if I were selecting a lunar mission, I would put some thought into selecting a second Lunar Polar Volatiles Explorer rover (which I suspect would be quite affordable assuming the first is built) sent to another region (perhaps the other lunar pole), or a lunar sample return mission like MoonRise, before this geophysical mission.  However, I bent my own rules enough by choosing 2 of the Decadal Survey's Mars Climate Orbiter concepts.  I didn't include carbon copies of earlier choices or current New Frontiers mission contenders as possible choices in the first place - I only want to select unique missions from the Decadal Survey's mission list.

Now let's take a look at the ambitious Venus Climate Mission.  This mission is intended to study the origin, variability, suspected major ancient climate change, and interaction with the surface of the mostly carbon dioxide atmosphere of Venus.  One angle of this study is to learn about potential climate change on Earth by comparison, and to test terrestrial General Circulation Models using Venus as a model test scenario.  The mission includes several distinct pieces of Venus hardware.

There is a Venus orbiter spacecraft that serves as a carrier and telecommunications rely for the other components.  The orbiter also includes a "Venus Monitoring" camera that gives context for the measurements from the elements of the mission that reach Venus itself.

There is a balloon that itself serves as a carrier and deployer for other mission elements.  The balloon is intended to last at least 3 weeks, floating 55km in the Venusian atmosphere and going around Venus up to 5 times during its journey.  The balloon has instruments that sample the atmosphere and clouds of the planet.  For example, it includes a Neutral Mass Spectrometer that can carefully measure noble gas isotopes.  A Tunable Laser Spectrometer measures trace gases.  The NMS and TLS should give even better results together than they would do individually.  A Nephelometer studies cloud particles.  Clues on atmospheric circulation are revealed by tracking the balloon as the atmosphere moves it about the planet.   

At 2 different times during the balloon mission, it deploys is a pair of small Drop Sondes.  These measure pressure, temperature, acceleration, and wind speed as they fall from the balloon to the surface over the course of 45 minutes using "Atmospheric Structure Instrumentation".  The balloon and Mini-Probe (which I will describe momentarily) also include similar instrumentation.  The Drop Sondes also include a Net Flux Radiometer to measure solar and Venus-based radiation.  Again, the balloon and Mini-Probe host similar instruments.  The Drop Sondes are tracked by the balloon to gain more data about winds at the various levels the Drop Sondes fall through.

The other element of the mission is a Mini-Probe that is larger and more capable than the 2 Drop Sondes.  It is released by the entry system at the same time as the balloon system, and falls for 45 minutes.  In addition to instruments like those the Drop Sondes carry, like the balloon system, it carries a Neutral Mass Spectrometer to measure aspects of Venus's atmospheric chemistry.  In this case the profile is taken vertically (i.e. the probe falls through the atmosphere as it takes measurements), whereas the balloon profile is generally horizontal.

The Venus Flagship Reference Mission has some commonalities with the Venus Climate Mission, but it's even more ambitious.  It includes 2 landers that last for several hours on the surface, 2 balloons, and a much more capable orbiter able to map Venus at a much higher resolution than Magellan did.  That mission is also much more expensive, and was not one of the ones on the Decadal Survey list, so I'm not considering it.

The Venus Mobile Explorer, another concept on the Decadal Survey list, also includes a Neutral Mass Spectrometer, Tunable Laser Spectrometer, and pressure/temperature/wind sensors for analysis of the atmosphere at different altitudes.  It's able to land and later float to one other location on the surface.  It has fewer climate/atmosphere capabilities than the Venus Climate Mission and may cost a bit more, but it gains surface capabilities and imaging.

The Venus Intrepid Tessera Lander, another mission studied by the Decadal Survey, includes similar atmosphere instrumentation on a lander mission, but at a projected cost ($1.3B in FY15 dollars with reserves) that is lower than either the Venus Mobile Explorer or the Venus Climate Mission.

When finding a partner for the Mars Climate Mission, the Venus Climate Mission comes to mind first, but these other missions should also be considered, since they have some climate capabilities mixed in with surface analysis.

As with the lunar geophysical mission, I would consider the SAGE (Surface and Atmosphere Geochemical Explorer) Venus mission in the current New Frontiers competition as a strong alternative to the Venus Climate Mission.  SAGE consists of a lander that would survive for at least 3 hours on a Venus volcano.  It can dig and analyze samples, and also includes a number of instruments to study the climate and atmosphere of Venus (including the Atmospheric Structure Investigation, Tunable Laser Spectrometer, and Neutral Mass Spectrometer, which I assume are similar to the ones of the climate mission).  However, SAGE is not on the Decadal Survey list, so I'm not including it as a possible choice.  Allowing the 3 current New Frontiers competitors could have taken a lot of the fun out of this survey of Decadal Survey options since I could very well have given 3 of the top 5 spots to them.

The combination of a Venus Climate mission, various climate studies of Earth (including those based on satellite data), and surface and orbiter Mars Climate missions (as I already selected for the 3rd most compelling mission) should give us a lot of practical data to allow us to compare climate at these planets.  Of course learning about implications for Earth from the other 2 planets is the immediately practical aspect, and it's a compelling one.  However, I'm concerned about the cost of the Venus Climate mission, estimated at $1.577B in FY15 dollars with reserves.  I already selected the Enceladus Orbiter as a Flagship class mission, and I'm inclined to limit the number of flagship missions to allow a greater number of less costly (but, it should be admitted, less capable) missions to fly.  As a result, even though in one sense I consider the Venus Climate mission to be the more compelling of the 2 missions by a hair, when factoring in cost, the Lunar Geophyiscal Network wins.  I select LGN as the 5th and last of my "top 5 most compelling missions" from the Decadal Survey.  The LGN folks shouldn't rest easy, though, because if an international partner picks up the costs for one or two of the significant components of the Venus Climate mission, thereby lowering the cost of the mission to NASA (which I think could be done given the several distinct parts of the mission), the Venus mission would probably bump LGN off the list and into spot #6.

Now that I've selected my personal top 5 selections from the Planetary Science Decadal Survey, in the next post I'll take a look at some ideas for the rest of NASA's Planetary Science mission budget.  I've come up with a top 5 list that only gets to 3 destinations, so it would nice to see where else we can go.  I may also discuss how my 5 most compelling selections fit with the theme of this blog.

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.