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.

3 comments:

Anonymous said...

Ray -

vkane from futureplanets. Nice series on your picks for compelling missions. I'd be interesting in an email chat: vkane56[at]hotmail.com.

Phil Horzempa said...

I think that this is an excellent series on Compelling Science Missions. Also, an excellent blog.
My concern for the coming decade is the new Austerity Age facing NASA. With budget cuts of 10% to 20% coming soon, it is time for NASA and the Decadal Survey to get serious about re-thinking our approach to Planetary Exploration. I think that NASA must return to the days of Dan Goldin's FBC philosophy, not because it is preferable, but because it will be the only way Planetary Missions will fly. This does not necessarily mean building shoddy spacecraft. Rather, it will mean building less capable spacecraft, ones with a simpler payload and less ambitious goals.
I like the design of the MAX-C Mars Rover. However, I agree that the price tag of $2.2 Billion is a non-starter in this new Age of Austerity. I think that NASA must do some serious redesigning of MAX-C with the goal of making it a less expensive vehicle. Since we do not want the risk level to rise too much, this will mean building a less capable rover.
The MAX-C rover is meant to be Stage #1 of Mars Sample Return, MSR. Ideally, MAX-C would have a very capable suite of science instruments. This is meant to give MAX-C the ability to choose the best samples to cache. However, the Mars community may have to be happy with a collection of returned samples that have not been completely characterized before caching and return.
In addition, a smaller payload results in a cascade of savings in weight and budget. It will mean a simpler buildup and checkout. It will mean larger reserves in both mass and budget. Inadequate reserves have been the cause of many cost-overruns in the Planetary Program.
Also, eliminating the objective of a pinpoint landing will save time and money. It will also mean that some desirable sampling sites on Mars will be out of reach. However, in this Age of Austerity, this kind of compromise will be required.
This re-thinking of our approach to MAX-C and MSR is an example of the new approach to unmanned Planetary flight that will be needed to get any missions launched in the coming decade. Other destinations in the Solar System, such as Europa, Titan, Io, Enceladus, call out to us for Exploration. However, to see missions fly to those worlds, we need to scale back our visions of complex craft such as the Jupiter Europa Orbiter, JEO. Such Flagship missions are unaffordable in this new age. We must look to the simpler, cheaper missions for our ticket to those fascinating worlds. We have the smarts to do it, and to do it without raising the risk level substantially.
Phil Horzempa

Phil Horzempa said...

I think that this is an excellent series on Compelling Science Missions. Also, an excellent blog.
My concern for the coming decade is the new Austerity Age facing NASA. With budget cuts of 10% to 20% coming soon, it is time for NASA and the Decadal Survey to get serious about re-thinking our approach to Planetary Exploration. I think that NASA must return to the days of Dan Goldin's FBC philosophy, not because it is preferable, but because it will be the only way Planetary Missions will fly. This does not necessarily mean building shoddy spacecraft. Rather, it will mean building less capable spacecraft, ones with a simpler payload and less ambitious goals.
I like the design of the MAX-C Mars Rover. However, I agree that the price tag of $2.2 Billion is a non-starter in this new Age of Austerity. I think that NASA must do some serious redesigning of MAX-C with the goal of making it a less expensive vehicle. Since we do not want the risk level to rise too much, this will mean building a less capable rover.
The MAX-C rover is meant to be Stage #1 of Mars Sample Return, MSR. Ideally, MAX-C would have a very capable suite of science instruments. This is meant to give MAX-C the ability to choose the best samples to cache. However, the Mars community may have to be happy with a collection of returned samples that have not been completely characterized before caching and return.
In addition, a smaller payload results in a cascade of savings in weight and budget. It will mean a simpler buildup and checkout. It will mean larger reserves in both mass and budget. Inadequate reserves have been the cause of many cost-overruns in the Planetary Program.
Also, eliminating the objective of a pinpoint landing will save time and money. It will also mean that some desirable sampling sites on Mars will be out of reach. However, in this Age of Austerity, this kind of compromise will be required.
This re-thinking of our approach to MAX-C and MSR is an example of the new approach to unmanned Planetary flight that will be needed to get any missions launched in the coming decade. Other destinations in the Solar System, such as Europa, Titan, Io, Enceladus, call out to us for Exploration. However, to see missions fly to those worlds, we need to scale back our visions of complex craft such as the Jupiter Europa Orbiter, JEO. Such Flagship missions are unaffordable in this new age. We must look to the simpler, cheaper missions for our ticket to those fascinating worlds. We have the smarts to do it, and to do it without raising the risk level substantially.
Phil Horzempa