Saturday, March 28, 2009
Ted Stryk has a guest blog at the Planetary Society's web page summarizing the talks given on future mission concepts at the Lunar and Planetary Science Conference. These are the same missions that I summarized from their abstracts a month and a half ago.
Ted's summary is well worth reading, even after learning that a favorite mission of mine for the next New Frontiers mission, Cerberus, a Mars geophysical mission, has been cut from consideration. It appears that JPL is holding its own internal competition among New Frontiers concepts. A $650M contract is big business, and my guess is that JPL will put its efforts into creating the best possible proposals for what it considers to be the best one or two candidates. I've heard that the Kevin Baines' Venus balloon mission also was cut in the internal competition.
Stryk's summaries from the LPSC presentations
My summaries from the abstracts
40th Lunar and Planetary Science Conference
Stryk's abstract from LPSC on reprocessing Voyager 2's Triton photos
Stryk's webpage of planetary photos
Friday, March 27, 2009
The journal Nature has just posted an interview with the new chair of the Decadal Survey, Steve Squyres. The short version: Squyres will focus on ensuring realistic cost and feasibility estimates; no missions are sacred, and even the Jupiter Europa orbiter and Mars Sample Return can be removed from the roadmap; and he promises that he won't advocate for Mars.
You can read the entire interview here.
Thursday, March 26, 2009
The subscription-only journal Science has a long article in this week's issue (March 27, 2009) discussing the problems facing NASA and ESA in planning a joint Mars exploration program. A joint program is the goal of the heads of the two space agencies' science divisions. They plan to have worked out a program by this summer for both a joint 2016 mission and a series of follow on missions culminating in a joint sample return mission.
The crux of the problem for both agencies is money. The current ExoMars rover and lander (both substantial science platforms) is $1.56B, and ESA's member nations have pledged only $1.1B. After the Mars Science Laboratory (MSL) cost overruns, NASA will have only $700 for a 2016 mission, with $50-80M of that pledged for ExoMars instruments. NASA would like to do a Mars orbiter for 2016 that would act as a long-lived communication relay for landers and rovers, follow up on the discovery of methane in the atmosphere, and continue high resolution imaging of the surface. With the money available, however, the orbiter that could be flown would have a limited instrument suite. The article quotes the head of NASA's MEPAG Mars science community group as saying that what can be done as, "Not much."
The article goes on to list the problems facing the creation of a joint program:
o One ExoMars investigator is said to state that bringing in the U.S. or Russia into the mission will simply delay it. On the other hand, a former NASA official is quoted to point out that ESA's first attempt to land on Mars (Beagle 2 was not an official ESA project) will be ExoMars, and it is more complicated than NASA's MSL.
o The budgeting process of the two agencies will be hard to synch. NASA plans in terms of multi-mission roadmaps, while ESA plans in terms of single missions. NASA, however, is funded annually while ESA has greater funding stability.
o There is not agreement in the science community that there should be a sequence of missions between MSL (2011) and ExoMars (2016) and Mars Sample Return (MSR). One ExoMars scientist is quoted as saying that Mars exploration should go from ExoMars to MSR in 2018. Right now, NASA is thinking of a mid-capability rover in 2018 and possibly a joint network mission with ESA in 2020 before MSR.
The article lists the price tag for MSR as $6-8B. This is $2B higher than I've seen in the past.
Editorial thoughts: I think that the problems discussed at some length (it's a two page article) are real. It will be interesting to see if the two agencies can work them out. Mars has become expensive. All the missions I've read about for the next decade in NASA documents, not including MSR, are $1-1.5B each. If NASA funds the Jupiter Europa mission, flies MSL and the Mars MAVEN orbiter, and launches several New Frontiers and Discovery missions, there may be room in NASA's budget for only one or two of this class of mission in the coming decade. ESA faces a similar problem in looking for good missions to fly to Mars. Together, more can be done.
It seems to me that the key question around the entire Mars and planetary program is whether or not MSR is monetarily feasible. At the high end of the costs quoted in the Science article, MSR could be the entire planetary mission program for both agencies for almost a decade at current budget levels. I have not heard of the political support in the U.S. to substantially increase the planetary exploration program to fund both MSR and a set of other missions. I am hoping that the Decadal Survey will finally settle the monetary priorities. Is MSR so compelling that it is worth all the missions that could be flown in its stead? If so, we should put our resources behind finally flying it. If not, then we should take it off the roadmap so that the best Mars and planetary program can be planned.
Wednesday, March 25, 2009
The next Decadal Survey for planetary missions is taking shape. I am encourage by what I'm reading (but more on that in the editorial notes).
Steven Squyres, at Cornell University and PI for the MER Mars Rover, has been named chair and Larry Soderblom, from the USGS Astrogeology Team in Flagstaff, Arizona, has been named vice-chair. Over the next two and a half years, the Decadal Survey will prepare a report that:
- An "inventory of top-level scientific questions that should guide flight programs and supporting research programs"
- Recommend the "optimum balance among small, medium, and large missions"
- Create a "prioritized list of major flight investigations in the New Frontiers and larger classes recommended for initiation over the decade 2011-2020'"
- Prepare "a prioritized list of major flight investigations in the New Frontiers and larger classes recommended for initiation over the decade 2011-2020"
- Create a "list of important science goals which could be achieved by small spacecraft (Discovery and Scout class) missions"
The process will be organized by panels focused on different classes of solar system bodies: inner planets, Mars, outer planets, outer planet satellites, and primitive bodies (asteroids and comets). These panels will take input from established panels (such as MEPAG, VEXAG, etc.), from town halls, from ad hoc groups of scientists with a shared interests, and individuals (with a specific note including input from students).
The following points from the latest Decadal Survey emphasize key points that will be different than the process last time:
"Compared to previous decadal surveys, this one will place much greater emphasison evaluation of the technical maturity and probable costs of candidate missions.
- The Panels and the Steering Committee will include members who are expert in engineering, project management, and cost estimation.
- Resources are available to do moderate-fidelity (and conservative!) cost estimates for a limited number of high-priority candidate missions.
- The objective is to produce a realistic (i.e., not heavily over-subscribed) set of candidate missions for NASA to carry out in the coming decade."
Another key aspect of the Decadal Survey will be that "Mars missions will be considered on an equal basis with all other missions. No 'set aside'for Mars exploration will be assumed a priori."
Editorial thoughts: I am encouraged by the early direction the Decadal Survey is taking. NASA and the planetary community have clearly learned from the mistakes of the last Survey, which nevertheless provided the roadmap for the planetary exploration program of the past decade. It turned out that only a portion of the program could be implemented within the available budget. (And a more capable and expensive Mars Science Laboratory was substituted for the one prioritized by the Survey.)
I expect that the Survey will still prioritize more missions than can be afforded. In my days of working budget processes, you always asked for more than you expected. What I will be looking for is a clear set of priorities both among missions and among classes of missions. If that is clear, then the highest priorities should be funded (assuming similar budgets for the next decade).
I would also be surprised if Mars does not remain a high priority and receives a good portion of the proposed resources. Looking at various mission proposals, Mars is simply cheaper to explore both because it is close and it has a relatively benign environment. A mission similar to the Jupiter Europa Orbiter (~$3B), for example, would probably be a half to a third that much at Mars.
Here are some predictions (I'll try to remember to score them in two and a half years).
- I expect that Mars will get around one-third of the mission development funds, Jupiter Europa another third, and New Frontiers and Discovery missions will receive the remaining third.
- The tough discussion will be between preparing for a Venus or Titan Flagship mission the following decade. Both deserve investigation, but if NASA can afford one Flagship mission in the 2020s (as it has in the 2000's and 2010's), only one is likely to fly. My guess is that the Survey will call for early development for both to enable a competition between them in about a decade.
- The other tough debate will be around the list of priorities for the Discovery and New Frontiers missions. The priorities set in the last Survey have guided the selection of these mssions in the past decade. Because these missions are led by individual researchers who have specific missions they want to see fly, the desire to get particular goals prioritized will be strong.
I welcome your predictions in the comments.
Decadal Survey home page
Latest presentation on process to be followed
Monday, March 23, 2009
So begins an article by long time space journalist Leonard David. He reports on the on-going debate on how to restructure the Mars program following the delay and cost overrun of the Mars Science Laboratory (MSL). In addition to the delay to this Flagship-class mission, funding the overrun is draining NASA's advanced technology programs for future Mars missions. NASA had planned on having technologies to allow for ever more pinpoint landings, opening up new places on the surface to visit. It also planned to spend to develop technologies for a Mars Sample Return (MSR) mission. Now those capabilities will be delayed at least two years and perhaps more as teams need to be rebuilt when money becomes available.
David reports that one leading Mars scientist, Chris McKay of the Ames Research Center writes that three factors will lead to a substantial revamping of the Mars program: (1) the delay and cost overrun of MSL, (2) missions that go beyond the capabilities of past and planned missions will be in the Flagship ($2-3B) cost realm, and (3) other locations for searching for life such as Enceladus and Titan provide alternative destinations. McKay still believes the Mars deserves to be the focus of robotic planetary missions, but as a lead in to future manned exploration.
Another Mars Researcher is quoted by David, Bruce Jakosky of the University of Colorado at Boulder, as saying that the Mars program remains fundamentally sound. While the program needs to be replanned, there are many options for cheaper missions. (Jakosky's Mars Maven planned for launch in 2013 will cost around $450M.)
Editorial Thoughts: I feel that this debate feels like the glass half empty versus the glass half full discussion. Yes, the Mars and NASA's overall planetary programs will take a major hit from the MSL delay. Yes, other good missions could have been flown for what MSL will cost. However, there isn't a right answer to how much should be spent exploring Mars. It is a subjective question of balance between Mars and other destinations. The most critical decision of the upcoming Decadal Survey, in my opinion, will be on the balance between funding for future Mars missions versus those other destinations. A case could be made for devoting the entire budget to Mars [let's focus on exploring one world in depth], for devoting none of it to Mars [Mars has been the focus for the last 15 years and it's time to move one], to virtually any balance in between. If the Decadal Survey simply lists a number of good missions whose probable costs exceed probable funding, then in my opinion it will not have made the hard decision of how to set priorities.
I also don't feel that flying ever more complicated missions to Mars is the onlyway to expand our knowledge of the Red Planet. (I say this knowing that many more knowledgeable than I are likely to disagree.) We could have a strategy of flying a series of rovers more capable than Spirit and Opportunity but less capable than MSL to a number of locations to find the one most deserving of a future flagship-class mission (be it a rover, a deep driller, or a sample return). We could focus on exploring Mars as a system and spend a decade putting simple network landers across the surface and a series of orbiters to address questions left unanswered by past and planned missions. (The science team that debated the focus of the planned Mars Science Orbiter (which may fly in a reduced configuration in 2016) identified three core study areas that future orbiters could focus on.)
I'm not saying that this should be our goal at Mars -- they don't pay me the big bucks to make those decisions and nor do I feel well enough informed. I do think that there are a range of mission options and price tags that could continue our exploration of Mars.
Resources: Leonard David's article at Space.com
Sunday, March 22, 2009
David has an extensive summary of the trade offs. While technology has advanced in the intervening three decades (yes, MSR has been seriously studied for longer than that), the physics remain unchanged, and, as so far as I know, the basics of rocket fuels has not advanced much.
To cut to the chase, direct return to Earth would require too much mass to be launched to Mars for it to be practical.
To give an idea of how difficult MSR is, think of all the steps that much be successfully accomplished:
Find an excellent place to collect samples. Remote sensing from orbit helps, but you can get skunked. As a thought exercise, several Mars researchers looked at various outcomes from the Mars Science Laboratory, and here's their description of one hypothetical scenario for getting skunked at what looked from orbit as a promising site: "
MSL goes to the delta deposits of Eberswalde. The delta depositional environment is confirmed, but we discover that this kind of facies on Mars is not good for preservation of organic compounds and evidence of fossil life. The clay minerals are limited to thin rock coatings, with minimal amounts of water involved in their formation. There is no sign of organic compounds, likely due to the oxidant compounds found in the rocks. "
A rover must be dispatched and safely landed on Mars to collect the samples. This rover could either arrive separately from the ascent vehicle lander (i.e., some years before in a previous launch window) or with the ascent vehicle. In the former case, we would know that interesting samples were found. However, even in this case, the lander with ascent vehicle would need to carry a small rover to go fetch the sample cache from the previously flown rover. (MSR could be done without a rover, but think of all the uninteresting locations the MER rovers have visited to find the really interesting locations. Imagine if a MSR lander without a rover had landed in the same place as Opportunity. It could stare at that wonderful bedrock just a few meters away but out of reach without a rover.) The ascent vehicle plus a rover and other sampling tools much be safely landed on Mars. Samples must be transferred from the rover(s) to the ascent vehicle. The ascent vehicle must then launch and reach Martian orbit. The Earth return orbiter must enter Martian orbit and autonomously rendezvous with the ascent vehicle. The sample cache must be transfered from one vehicle to another. The Earth return orbiter must break free of Martian orbit and carry the samples back to Earth. At Earth, the samples are returned in an atmospheric return capsule much like what was done for the Stardust comet samples.
MSR promises to provide a scientific bonanza if all these elements (many of which require extensive technology development) can be made to work. If any element fails, then the entire investment is lost. This is why estimates for MSR range from $3B (seems too low in my amateur armchair estimation) to $5-6B. Fortunately, all the separate elements makes international cooperation fairly straightforward. That, too, could be problematic. If any nation withdraws its development of a key element, then the investments of the other nations are put at risk.
A lot of momentum has built behind MSR in the last couple of years. It will be interesting to see if the issues above are addressed successfully by the international consortium of space agencies that have expressed interest.
Science priorities for MSR
Saturday, March 21, 2009
The last two VEXAG meetings (in May 2008 and February 2009) had status updates for the upcoming 2010 Japanese Venus orbiter, otherwise known as Planet-C. This mission will focus on atmospheric studies, with some measurements of the surface through atmospheric spectral windows. The missions goals (from the 2008 presentation) will be to:
- Study atmospheric dynamics including Venus' super rotation, circulation, and meso-scale phenomenon
- Other atmospheric studies relating to lightning and cloud physics
- Surface studies including searching for active volcanos and geological survey of surface minerals
The mission will use the extremely fast rotation of the upper atmosphere (the super rotation) to allow multi-hour observations of atmospheric dynamics. The orbiter will assume an elliptical equitorial orbit. For 24 hours, the 5 cameras on board will observe planet as the upper atmosphere rotates below in near synchronicity with the orbiter. This will allow the study of the small scale dynamics of the upper atmosphere.
The Japanese mission will overlap with the expected extension of Europe's Venus Express mission. That "spacecraft is in a good health [sic] and very productive, but shows some signs of ageing." It appears from the ESA update at the VEXAG meeting that the limiting resource (barring catastrophic failure) will be the fuel supply, which is expected to last well into 2013. The overlap of the Japanese and ESA missions will allow simultaneous measurements at Venus from different orbits and from different suites of instruments.
JAXA Planet-C website
Planet-C 2008 VEXAG update (with information on scientific goals)
Planet-C 2009 VEXAG update (mostly engineering and schedule)
ESA Venus Express VEXAG update
Thursday, March 19, 2009
The Venus Exploration Analysis Group (VEXAG) met in late February. Per its website, "The Venus Exploration Analysis Group (VEXAG) was established by NASA in July 2005 to identify scientific priorities and strategy for exploration of Venus."
As usual, the meeting included a number of presentations. It was also followed by a Venus Geochemistry meeting that discussed scientific results and future mission plans. To keep these blog entries to a reasonable length, I'll review the presentations a couple at a time. Then I'll switch to reporting on the last Outer Planets Assessment Group (OPAG) meeting before returning to talk about the proposed Venus Flagship mission.
An update on the overall planetary program was given by James Green, Director of NASA's Planetary Division. Most of the presentation was a review of the current list of planned missions, a recap of the Mars Science Laboratory slip, and a reminder that Europa is the goal of the next outer planets Flagship mission. Green stated that the next New Frontiers Announcement of Opportunity (AO) is still being revised, but there isn't a date for its completion. There is a draft AO available that the planetary community has provided comments on, and a number of teams are preparing their proposals based on it. The MSL problems, however, slipped the schedule for the New Frontiers AO. Once the AO is formally released, we'll have the revised schedule for the selection of the next mission in this program. Sometime after the release of the New Frontiers AO will be an AO for the next Discovery mission competition. It still has not been decided whether or not radioisotope power systems will be made available for the next Discovery mission.
Ellen Stofan, chair of VEXAG, also presented a list of issues and questions on the group's plate. The largest task for this year will be to provide input into the Decadal Survey for Venus Missions. Far more missions will be proposed for the next decade by all the interest groups in the planetary community than could be flown. Getting your missions to be ranked as priorities requires defining compelling scientific questions and feasible (in terms of technology and dollars) missions to address those questions. It appears that VEXAG will use questions formulated in a previous 2007 VEXAG goals and objectives white paper as its starting point. The three highest priority goals (from Stofan's presentation) are:
"Present: Venus as a Terrestrial Planet: What are the processes that have shaped and still shape the planet?
"Future: Implications for Earth: What does Venus tell us about the fate of Earth’s environment?"
James Green Planetary Division Update
Ellen Stofan's VEXAG status and meeting goals
VEXAG's Venus Exploration Goals, Objectives, Investigations, and Priorities: 2007
Decadal Survey process overview
I will admit to some confusion to the wealth of groups that provide input to NASA on it's planetary program. Like its Mars (MEPAG), outer planets (OPAG), and small bodies (SBAG) counterparts, MEPAG, VEXAG provides science community input into NASA on Venus science. It is not an advisory board, however, although NASA listens to and often acts on its input. There is also a Venus Science and Technology Definition Team that spent 2008 defining a Flagship-class mission for the 2020s for Venus. While this Team was formed based on VEXAG's "input", I'm not sure if it is formally a part of VEXAG or just works closely with it. In addition to the xAG's, there is also the Planetary Sciences Subcommittee of the NASA Advisory Council, which appears to be a formal advisory board that also is composed of planetary scientists, many of whom also serve on the xAGs.
The good news for those of interested in planetary exploration, all these groups post the presentations made at the meetings. This gives us insight into NASA plans and problems that was nearly impossible to get in past decades. I'm sure I wasn't the only person to make a weekly trip to the local library in years past to scan Aviation Week and Space Technology in hopes of finding a tidbit on plans and problems.
Monday, March 16, 2009
Aviation Week in its subscription only print edition has an article describing how the ESA ExoMars mission "is now struggling to stay within its specified weight limits, making the downsizing of its science paload seeminly inevitable." This comes on top of the mission's challenges to fund the mission: "Only 850 million [euro] ($1billion) of the mission's estimated 1.2 billion [euro] price-tag has been committed so far and, despite talks with NASA and Russia about joining forces on the mission, planners are skeptical they will obtain the full amount needed."
This article led me to read up on ExoMars on the web and in the update presented at the last Mars Exploration Program Analysis Group (MEPAG) meeting (see links to resources below). ExoMars has effectively grown into two sophisticated missions. The first is the rover that most readers of this blog are familiar with. It will focus on exploring Mars for signs of past or present life. It carries the Pasteur package of 12 instruments that was originally estimated at 16.5 kg and now estimated at 24 kg.
The second mission is housed in the lander stage that carries the rover to the Martian surface. It carries the Aurora package of 11 instruments that was originally estimated at 20 kg and now estimated at 60 kg. This lander would be the first sophisticated geophysics package delivered to Mars with instruments to study seismology, the radiation environment at the surface of Mars, meteorology, and magnetics among other goals.
The MEPAG ExoMars presentation clearly laid out the priorities for the mission in order of priority:
"To search for signs of past and present life on Mars;
To characterize the water/geochemical environment as a function of depth in the shallow subsurface;
To study the surface environment and identify hazards to future human missions;
To investigate the planet’s subsurface and deep interior to better understand its evolution and habitability."
The presentation also showed a landing band between 5 degrees south and 45 degrees north. Areas circled included northern plains where subsurface ice may lie within a meter of the surface -- within the reach of the rover's drill. Other sites circled include low elevation ancient cratered terrain including Mawrth Vallis which has phyllosilicate (clay) minerals and Meridiani.
I was surprised by the growth in the ambitions for the geophysics package; I guess that I haven't paid enough attention to the mission. Given the priorities for the mission, the many of the measurements of the Aurora package appear to be lower priority. I would expect cuts in its instruments before those of the rover based on these priorities. Unfortunately, the seismology instrument appears to be included based on the lowest priority goals for the mission. A network mission for Mars is high priority for the coming decade by both NASA and ESA. I've read elsewhere that having the seismology of Mars characterized by ExoMars would aid in the design of the seismology instruments for the follow on network mission.
MEPAG Exo Mars Presentation
A description of instruments planned for both the rover and lander can be found at http://www.scitech.ac.uk/SciProg/Aurora/ExoMars/ExoMarsHome.aspx Click on "next" for a brief overview of the mission followed by instrument descriptions.
ESA ExoMars website
Sunday, March 15, 2009
"The Venus In Situ Explorer (VISE) mission is a detailed exploration and study of the composition of Venus’s atmosphere and surface materials... VISE will make compositional and isotopic measurements of the atmosphere on descent and of the surface on landing. A core sample is obtained at the surface and lofted to altitude where further geochemical and mineralogical analyses are made. In situ measurements of winds and radiometry are obtained during descent and at the balloon station. Scientific data obtained by this mission would help to constrain the history and stability of the Venus greenhouse and the recent geologic history, including resurfacing. The technology development achieved for this mission will pave the way for a potentially paradigm altering sample-return mission in the following decade... Science measurements will be made during three VISE mission phases: (1) the descent phase [in which the lander would inflate a balloon to be lifted into the cooler reaches of the atmosphere], with atmospheric experiments and descent imaging; (2) the landed phase, with surface imaging and atmospheric and surface chemistry; and (3) the ascent phase, with surface mineralogy and atmospheric circulation analysis." - New Frontiers in the Solar System: An Integrated Exploration Strategy (2003)
The planetary Decadal Survey published in 2003 called for a regular program of New Frontier missions that would be medium priced (~$650M today). Included in the list of candidate missions was the VISE mission. It had two primary goals: (1) resolve the key questions about the composition of the Venus atmosphere, particularly the lower atmosphere not measured by the Pioneer Venus probes in 1978 (2) provide for detailed chemical analysis of surface samples. The Soviet Venera landers had previously sampled the surface, but their chemical analyses had to be completed in less than an hour. To measure the surface composition in the detail desired would require hours of data collection, too long for a lander to survive in the hellish heat of Venus' surface. To get around this problem, VISE would collect a sample, bring it inside the lander, and then inflate a balloon to carry out a leisurely analysis in the cooler upper atmosphere.
A Venus in situ mission remains a priority for Venus exploration. This blog entry will look at one mission that was proposed to fulfill the goals of VISE, and discuss possible new directions for Venus exploration today.
So far as I know, no one has proposed a Venus lander for the New Frontiers mission as elaborate as that envisioned VISE mission. However, a mission with two simpler landers was proposed for the second New Frontiers selection competition. (There have been only three competitions. The first was limited to Pluto missions and resulted in the New Horizons mission. The second selected the Jupiter Juno mission. The third is in progress.) Called the Surface and Atmospheric Geochemical Explorer (SAGE), the mission in many ways would have been an upgraded Venera mission. You may recall that the Soviet Venera landers were dropped off by flyby craft to make measurements during the atmospheric descent and for 30 - 60 minutes on the surface. Data relay was done through the flyby craft. The SAGE mission had a similar concept, except that two landers would be carried, one targeted at the extensive Venusian plains and one at the highlands (tessera). Capabilities of the landers would be considerably upgraded versus the Soviet landers. (Technology would have progressed in the nearly 20 years since the last Venera mission.) SAGE would make chemical analyses of the atmosphere all the way to the surface. During the latter parts of the descent, it would have taken descent images that would have provided our first high resolution images of areas of Venus larger than the immediate area in front of the landers. SAGE would also have a pancam camera on a periscope, presumably to take panoramic images of the landscape around each lander.
In other ways, SAGE was very much like the Venera landers. It would have only an hour -- perhaps two -- on the surface before heat would end its mission. During that time, an arm would grab a sample [presumably from a fixed location relative to the lander] and delivered that sample to an air lock. Once inside the lander, an X-Ray Fluorescence and Diffraction spectrometer would analyze the surface sample. A dedicated microscopic imager in the lander would image the area from which the sample had been taken.
The geometry of the mission trajectory and the need to sequentially collect each lander's data by the carrier craft would have limited the choice of landing sites to a circle around the Venusian globe. Landing sites would have been further limited by the need to land in areas where the circle lay in daylight.
The presentation describing the SAGE mission listed a number of challenges that would have to be resolved. Developing craft and instruments that could survive the heat and pressures at the Venus surface within the New Frontiers budget were among them. [I have heard that these challenges have been major obstacles for Venus in situ Discovery and New Frontiers missions. Venus is hard to explore, and hard equals higher risk and costs.] Test facilities that replicated the Venus surface would have to be built. Doing all of this technology and test facility development within the time frame allotted for a New Frontiers mission development was also listed as a risk. And the best launch opportunity for SAGE lay outside the allowed time frame for the second New Frontiers mission. [I have heard through the internet grapevine -- for whatever that is worth -- that this ultimately disqualified SAGE. If so, ironically, the launch of the second New Frontiers mission was delayed past the original deadline to fit funding profiles.]
Update: In 2008, a new panel reviewed candidate missions for the New Frontiers program. They kept Venus in situ exploration as a candidate mission, however the goals were simplified: "The New Frontiers announcement of opportunity [for the mission selection that is in progress] should not exclude a Venus In Situ Explorer (VISE) mission that addresses the major goals for chemical sampling of Venus’s mid- to lower atmosphere and for characterizing atmospheric dynamics but that lacks a surface sampling component." It appears that including a landed mission component within the New Frontiers mission may not be possible within the allocated budget. The Venus Exploration Analysis Group (VEXAG) looked at a SAGE-like mission and estimated its costs at ~$800M. That is not necessarily outside the New Frontiers mission scope. The craft plus instruments and operation must fit within $650M, but the launch vehicle does not. The VEXAG document does not state what was included within its estimate. However, it seems likely that SAGE would be a tight fit if it is possible within a New Frontiers budget.
SAGE's limited surface lifetime would also limit the quality of the chemical analysis of the soil or rock collected. Recent work has suggested that stand off chemical laser analysis coupled with Raman spectroscopy may be possible for Venus. (This would be similar in concept to the Mars Science Laboratory's ChemCam instrument.) Such an instrument on a Venus lander could conduct chemical analysis at a number of points in the landing area. However, this would be another system that would need to be developed.
Editorial note: A SAGE like mission to Venus would be my preference for the next New Frontiers mission. It has simply been too long since we have visited the surface of Venus and there are key outstanding questions about the chemical composition of the atmosphere that bear on the formation and evolution of Venus. I suspect, however, that this may be too complex a mission for the New Frontiers budget. I would love to be proven wrong.
Presentation on SAGE
Summary of Venera 14 mission
New Frontiers in the Solar System: An Integrated Exploration Strategy (2003) (Original New Frontiers candidate mission goals)
Opening New Frontiers in Space: Choices for the Next New Frontiers Announcement of Opportunity (2008) (Updated New Frontiers candidate mission goals)
Wednesday, March 11, 2009
My thanks to Dr. Mustard for the correction.
The journal Nature has also printed a very brief comment on the proposals discussed in the last MEPAG meeting. They note that NASA and ESA officials are now looking for ways to launch NASA's Mars Science Orbiter (to pinpoint methane sources among other scientific goals and provide data relay for landed missions) and ESA's ExoMars rover on the same launch vehicle.
Missions for NASA's New Frontiers program are selected from a pre-approved list of candidate missions. (You can see the list of candidate targets in the poll to the right of this column.) I am slowly working my way through the list of candidate missions with just three more to go (including the one described below).
A mission to return samples from the moon has been on the New Frontiers candidate list since the beginning of the program and was re-affirmed as a candidate last year. This mission would return samples that can shed light on the early formation of the moon and solar system. The target for the sample return is the 2500 km-wide South Pole-Aitken (SPA) Basin, which is believed to be the oldest and deepest of the moon's basins. Unlike giant impact basins on the near side of the moon, the SPA basin never filled with lavas (which created the maria that are the darker areas on the moon's face). Data from the Clementine and Lunar Prospector missions suggested that the basin's surface could include material from the lunar lower crust and upper mantle. Returning samples from the basin would allow scientists to test their theories about how giant impacts influenced the development of planetary crusts and mantles.
In the words of the National Research Council report on recommended candidate New Frontiers missions:
"Melting of planetary surfaces (magma oceans) during the early accretion process of planetary bodies in the inner solar system is an important concept resulting from detailed analysis of the Apollo and Luna samples in Earth-based laboratories. The detailed analysis of samples from the South Pole-Aitken Basin Sample Return mission should verify and extend this central concept for the differentiation of the early planetary body into crust and mantle. Sample return allows samples to be analyzed with the most sophisticated instruments on Earth (many of which cannot be transported to the sampling location). And it has other benefits as well, providing the ability to share samples with many research teams for broad-based experimentation and the archiving of samples for analysis in the future when better instrumentation will exist. It is possible, for example, to conduct far more sophisticated analysis of Apollo samples today than it was when they were first returned to Earth."
"A South Pole-Aitken Basin Sample Return mission would directly address the following crosscutting themes and key questions identified in the decadal survey (numbering is taken from the decadal survey [of prioritized planetary missions published in 2003]):
The First Billion Years of Solar System History
1. What processes marked the initial stages of planet and satellite formation?
3. How did the impactor flux decay during the solar system’s youth and in what way(s) did this decline influence the timing of life’s emergence on Earth?
Processes: How Planetary Systems Work
11. How do the processes that shape the contemporary character of planetary bodies operate and interact?"
The report also notes that a SPA Basin sample return would provide "highly significant" information on the processes that led to the unique character of our home planet as well as information on the interior structure of planets. As well as being in a world in its own right, the moon is in many ways the Earth's fraternal twin. Current theories of the formation of the moon has it birthed from the collision of the proto-Earth and a Mars-sized world. In addition, the close proximity of the moon and Earth would have meant that the giant impacts still visible on the moon's surface also would have occured in on the Earth.
Two sample return missions were proposed for the SPA Basin by Michael Duke, then with the Colorado School of Mines and now retired. He first proposed the mission within the the Discovery program, but the mission was rejected as "risky for several reasons: (1) Concern that fragments, obtained from a single surface location, would be such a complex mixture of materials that fragments could not be adequately correlated to Basin units and address the principal goals of the mission (sample complexity); (2) There were no descope options – if costs were to rise, there was little in the mission concept that could be modified to reduce costs (programmatics); (3) Cost and mass margins were judged insufficient for a mission of such complexity; (4) The amount of time available for adapting to unforeseen anomalies was limited [sampling would have to occur during a single lunar day (~14 Earth days)]; and (5) There was insufficient consideration of landing risks." (http://www.lpi.usra.edu/meetings/lpsc2003/pdf/1684.pdf)
Duke resubmitted the sample return for the second New Frontiers selection. (The first selection, limited to missions to Pluto, resulted in the New Horizon spacecraft now in flight.) He described the goals of the mission and some of the strategy for addressing the shortcomings of the Discovery proposal. Specifics on the implementation were scarce. (These competitions are fierce and proposers often decline to provide details publicly that could help their competitors.) The biggest difference was that the New Frontiers mission would have used two landers. This would help mitigate the landing risk by providing a backup lander. Sampling two locations would increase the chance that a wide range of samples recording the history of the basin would be returned. Each lander would seive through 50 or more kilograms of lunar soil to collect hundreds of 4 - 10 mm rock fragments for a total sample of around 750 gm.
The New Frontiers proposal still would have had just a single lunar day to collect samples. Designing the landers to last through the long and cold lunar night apparently would have had added too much to the mission's costs. The proposal also include a small relay orbiter since the SPA Basin lies on the far side of the moon and direct Earth to lander communication would have been impossible.
Duke's proposal was selected as one of two semi-finalists in the competition, but in the end the Jupiter Juno mission was selected. I don't know if any other researcher has picked up where Duke left off to prepare a lunar sample return mission for the New Frontiers selection competition in progress. If someone does, they will benefit from the detailed mapping of the moon that has been carried out in recent years with more missions to come. That will enable careful selection of sample sites that both have a good chance of having desired material and would be safe to land on. Countering that, the problems experienced by the Mars Phoenix lander in acquiring samples may lead review teams to worry that a single lunar day is too short of a time to collect samples. Perhaps a new proposal will have a good answer to that concern.
Duke's description of the mission: Challenges for Sample Return From the Lunar South Pole -- Aitken Basin
A review of the mission at Robot Explorers
Description of the goals of a lunar return mission: Opening New Frontiers in Space: Choices for the Next New Frontiers Announcement of Opportunity
Monday, March 9, 2009
For those in the United States with cable TV, the National Geographic channel will have an episode on the Galileo mission to Jupiter Thursday night at 10 PM (but check your local listings in case they are different from mine). From the trailer, it looks to be solid discussion of science of the Jovian system.
Sunday, March 8, 2009
The Associated Press has an article on how frequently NASA's projects overrun their budgets. "Congress' financial watchdog, the Government Accountability Office, reviewed NASA's newest big-money projects and found most were either over budget, late or both."
Overruns have consequences, "Historically, overruns have caused NASA to run low on money, forcing it to shelve or delay other projects. Often, the agency just asks taxpayers for more money... 'The costs of badly run NASA projects are paid for with cutbacks or delays in NASA projects that didn't go over budget,' Stern wrote [in a separate opinion piece quoted in the Associated Press story]. 'Hence the guilty are rewarded and the innocent are punished.' "
It's easy to pick on NASA for poor cost estimations and the follow-on cost overruns. However, these seems to be endemic to technology development, whether in NASA, NOAA, the Defense Department, or ESA. Overruns, usually expressed as schedule slips, are rampant in the private sector, too. It one time in my career, I worked for a high tech Fortune 500 company, and was responsible for planning roadmaps of products with development costs in the hundreds of millions to billions of dollars. Schedule slips were so common, that I always doubled the quoted development cost (and halved the projected revenue -- sales forecasting was equally problematic) to see if the project still looked interesting.
I cannot offer an opinion on whether NASA is better or worse at estimating and managing costs than other agencies and companies that engage in high technology development. I simply have no knowledge one way or another. That also isn't the subject area of this blog.
Cost overruns, in my experience, can be minimized when projects are simple extensions of previous projects. Much of the technology has been developed, and the engineering teams have lots of experience. That also minimizes the aggressiveness of your missions or products.
What makes this article relevant to future planetary exploration is how to balance risk and predictability in planning a program of planetary exploration. I will be very interested to see how the Decadal Survey in progress balances low-risk-of-overrun missions with high-risk-of-overrun missions in its list of priority missions.
The astronomy decadal surveys have included both terrestrial and space projects. The planetary community adopted this process with a report in 2003 (more on that later). Since then, there have been decadal surveys in a number of subject areas: Solar and Space Physics (2002), Earth Observation from Space (2007), Life and Microgravity Sciences (in progress). A new astronomy survey is in progress. The new planetary survey is in the organizational stage with the availability of a pre-publication report in the first quarter of 2011.
The surveys go to great lengths to solicit a wide range of input from the planetary community. Panels are formed on a number of topic areas. The last planetary survey had 23 panels ranging in subject from Mars to near Earth object sample return to extraterrestrial mineralogy. (Look here for the Mars community's early thoughts on their input to the new survey.) In addition, individuals and ad-hoc groups of scientists can submit white papers to cover any areas not covered by the panels. For those of us in the public, the result will be a feast of mission ideas and descriptions. (I will be hard pressed to try to keep up with the deluge in this blog.) Based on the current schedule, look for these input documents and assessments to begin to become available in the second half of this year.
The inputs to the decision process as well as the final report are likely to have three broad subject areas: (1) solid (and usually readable by the public) reviews of the current state of knowledge, (2) prioritized key scientific questions, and (3) recommended missions or funding to address those questions. The latter is the subject of this blog, and so I'll reproduce the planned output in this area from the MEPAG meeting presentation:
• "Recommendations on the optimum balance across the solar system and among small, medium, and large missions and research activities;
• Prioritized recommendations for New Frontiers and flagship flight investigations for initiation in the period 2013-2022;
• Recommendations for NASA-funded research activities required to maximize the science return from the flight investigations; and
• Technology development needs and opportunities relevant to NASA."
I think that it's instructive to look at the recommendations from the last planetary survey:
Here's my scorecard on the output of these recommendations:
Cassini extended mission - funded two year extension with an additional seven year extended mission in discussion
Kuiper Belt - Pluto Explorer - launched as the New Horizons mission but approved prior to the publication of the Survey report
Jupiter polar orbiter with probes - in development as the Juno polar orbiter (as I understand it, NASA no longer has the facilities to test Jupiter atmospheric probes)
On-going program of medium class (New Frontiers) missions - one launched (New Horizons), one in development (Juno), and the selection of a third mission in progress
Europa geophysical orbiter - not started, but now selected for launch around 2020 as the Jupiter Europa flagship mission (about a decade later than recommended)
Mars Scout line - initiated with the Phoenix mission completed and the MAVEN mission in development; however preliminary Mars roadmap recommendations may not have the third flight until the late 2020s
Mars upper atmosphere orbiter - in development as the MAVEN scout mission
Mars network - not funded, but is a candidate mission for the next New Frontiers mission or as a ~2020 flight within the Mars program
Mars Science Laboratory - in development, although the mission to be flown is much more capable (and expensive) than the one envisioned in the Survey report
Mars sample return - earliest possible flight in the 2020s
Discovery mission launches every 18 months - Since the report, the MESSENGER Mercury mission has launched (and encountered Mercury twice), the Deep Impact mission was successful, and the Dawn asteroid mission is in flight. However, by my reckoning, only one new mission, the lunar GRAIL mission, has been approved since 2003. A new mission selection process is scheduled to begin this summer.
In addition to these recommended missions, the Survey listed a number of high priority missions that weren't included as recommended missions. All four of the medium class missions have been added as candidate missions for the next New Frontiers mission selection.
In summary, the results of the last Decadal Survey were mixed. The New Frontiers program was begun about a year before the completion of the last survey, and has progressed with periodic mission selections. The Discovery program should have had three to four new missions selected to keep on track to launch regularly in the coming decade. Neither large mission (Europa orbiter nor Mars sample return) was started, although the Mars Science Laboratory grew into a large, flagship class mission.
In general, the last Decadal Survey recommended a program that was too ambitions. By my rough accounting, it might have taken a budget twice the size actually provided by Congress to fly the entire mission suite. I can think of several reasons for this mismatch. First of all, the last Survey had only preliminary cost estimates to work with, and early cost estimates have a history of being too low. (For this next Survey, much more effort will be put into costing mission concepts.) Second, cost overruns hit several programs, reducing funds for starting new ones. And third (although I don't know if this was done consciously), managers know that you ask for more money or programs in your budget request than you expect to get. You might get lucky and get more resources, or if not, your budget likely will be cut down from your initial request, so ask big.
I suspect that the Survey that is just beginning will face several tough issues. Assuming that budgets for the next decade are similar to those of this past decade, creating a balance set of priorities that are actually likely to fly will be hard. If so, the arm wrestling to be highly prioritized and thus near the head of the line for funding may be rough. This is especially true, I think, in three areas:
• What should be the balance between smaller missions and larger missions? Clearly, funding since the last Survey was not enough to maintain regular approval of new Discovery missions.
• What should be the balance between the Mars program and the rest of the program? Mars has intentionally been the favored target for the last decade in terms of funding and missions. Should that continue or is it time for other destinations to receive priority?
• What flagship mission should follow the Jupiter Europa orbiter? This next mission would likely begin within the next decade, and several good candidates are likely to be proposed: Mars sample return, Venus flagship mission, Titan flagship mission are just the current contenders that I'm aware of. (If I were a betting man, I think I'd bet that the Survey will list 2 - 3 flagship missions for funding of technology development to enable a strong contest for the eventual selection near the end of the coming decade.)
Decadal Surveys are exercises in optimism. The community proposes its best ideas in the hope that the President and Congress will fund them. The coming decade may be an especially tough environment. We don't know how long the current economic troubles will continue. Once they stop, the U.S. will have to face the problems of large accumulated deficits. New problems (decline oil production? global warming?) may become national priorities for funding in place of an expansive planetary exploration program. Despite these problems, I expect that we will still have an on-going program of new planetary missions. If the budget for those missions declines for any of a number of reasons, then the prioritized list of missions expected from the Survey will be even more important to inform how to best use that budget.
You can use the box below to read or download the last Decadal Survey report or click here.
Friday, March 6, 2009
There have been several articles about a recent research report that Ceres could be the abode of life. While the speculation that Ceres could have been the source of life on Earth seems a bit far fetched (but, hey, it's a strange and wonderful universe, so who knows), it does give hints about what a fascinating world Ceres may present to the Dawn spacecraft when it arrives in 2015. Between now and then, we'll have an extended visit at the asteroid Vesta, which is fascinating in its own right.
Thursday, March 5, 2009
Mars has been blessed with a wealth of missions over the last decade plus. It has gone from a world in which there were serious arguments about whether there had been geologically significant amounts of water to one where a multiplicity of locations have been found that may contain biotic or pre-biotic chemical signatures. Michael Meyer, NASA's lead scientist for its Mars Exploration Program, had a presentation at the MEPAG meeting on the wealth of discoveries that have lead to fundamental new understandings of Mars. I won't try to summarize them -- his presentation speaks for itself and is fairly short. This is the fruit of a program of on-going missions to study new facets and new locations. And yet we still have just scratched the surface (literally) of Mars.
Another presentation from the meeting looks at possible responses to the results of the Mars Science Laboratory. (The same logic would also apply to results from ESA's ExoMars mission.) If MSL and/or ExoMars fails to find conditions that might have been suitable for past life, then the goal for follow on missions would be to explore new sites. On the other hand, should either mission find signs of past or present life, then the logical follow on mission would be to return to the same site with better instruments or better tools to collect samples (for example, from a greater depth in the soil).
I feel that our two most sophsiticated missions to Mars -- MSL and ExoMars -- may fundamentally change our goals for exploration. For that reason, I personally feel that planning for a Mars sample return (MSR) mission now is too early. I feel that we need more wheels on the ground at more sites before we know the right place to return samples from. This question, explore more or move to a sample return at the earliest possible time, has been debated at length in the scientific community. As a whole, the scientific community has voted to move forward with MSR at the earliest opportunity (which currently would be in the 2020s).
The results at Mars from a focused program show the benefits of an on-going, in-depth program of exploration. I think we will see some of the same benefits from the number of lunar missions in the recent past, on-going, and planned for the future. I personally would like to see the Jovian system made an international focus for the 2020s. By then, the Juno mission will have studied the deep interior of Jupiter. NASA's Jupiter Europa mission will enhance our understanding of Jupiter and its moons, and mapped Europa in detail. If ESA selects the Jupiter Ganymede orbiter in its next mission selection process, then Ganymede and Callisto will receive in-depth study. Even with these three missions, there are more that could be flown by other nations -- simple landers for the moons, magnetosphere explorers, an Io observer, or a Jupiter meterological observer.
Clearly, there are many other locations in the solar sysem that would benefit from focused studies. My opinion is just that, and I hope that you will share your preferences in your comments.
Wednesday, March 4, 2009
The science magazine Discover (April 2009 issue) has a colorful two page spread (sadly, not available on the web) on the solar probe mission scheduled for launch in 2015. This mission will use multiple Venus flybys to lower its perigee (perisol?) until the craft skims as low as 9.5 solar radii above the sun's equator. While the body of the craft hides behind a high tech sun shield, instruments will study the composition of material leaving the sun and image the activity on its surface. In the words of a preliminary study report that defined the mission:
This mission implementation is a lower cost version of an original plan that would have used a Jupiter flyby to enable a flight over the sun's poles and two encounters just four solar radii above the sun. That mission, however, was unaffordable with NASA's current budgets. The new plan trades closeness to the sun for the ability to make repeated passes within 35 solar radii in orbits that gradually lower to the planned minimum encounter distance for a minimum of three passes below 10 solar radii.
This full report provides a full description of the science, spacecraft and mission. The Solar Probe website itself hasn't been updated and much of the material reflects the previous, higher cost design.
There's no word on when the proposal for the follow on solar lander mission will be released.
Tuesday, March 3, 2009
A major theme of the roadmap discussions was discussing the possibility of international collaboration. The ESA update focused on ExoMars with some discussion of follow on missions. ExoMars will be a solar powered rover with a highly capable instrument suite focused on exobiology.
- ESA's member states have committed 850M euros towards the ExoMars rover, with another 150M euros to be paid for separately by member states. ESA believes it needs more like 1.2B euro (plus instruments) to execute the full mission. [The presentation says that NASA is planning to contribute up to $75M in instruments. I don't know if this is in addition to or part of the 150M euros.]
- ESA is looking for international cooperation with the U.S. and Russia to help close the funding gap. Even with this, ESA believes that the mission plan will have to be descoped.
- ESA is thinking of an on-going Mars program that would be a joint program with NASA in which ESA would contribute ~200-300M euro a year.
- ESA's presentation lists one scenario in which it would take the lead on the 2016 ExoMars rover, contribute to a NASA-led 2018 rover, and be part of a 2020 network mission. The long term goal is a joint Mars sample return mission.
Doug McCuistion's (NASA's director of the Mars exploration program) presentation also discussed future roadmap planning (along with a number of slides discussing the Mars Science Laboratory situation):
- His projected budget slide shows shows new mission development budgets of ~$300-400M per year for the first half of the next decade. That budget then ramps up considerably by the end of the decade to ~$900M with the assumption of a new start on a Mars sample return mission to begin in 2020. [This slide appears to be from a previous budget presentation to show previous expectations as a baseline for looking at a new roadmap. None of the other presentations in the meeting show MSR this early.]
- NASA has developed a series of guiding principles for its discussions with ESA on a joint Mars program. NASA wants to provide the entry, descent, and landing system for at least one mission in 2016 or 2018 to maintain its core competency in this area. For the same reasons, it wants to provide the surface system in at least one of those mission opportunities. NASA also does not want to provide the launch vehicle for more than one of those opportunities [presumably to avoid the cost]. In addition, the missions executed jointly must show progress toward MSR.
- McCuistion's presentation says that ESA would like to have a data relay orbiter for the 2016 mission.
- The joint mission plans must be "budetarily and technically realistic." Two plans apprently will be developed: "What we can afford to do, and the 'best' partnership."
The Mars Architecture Tiger Team (MATT) then presented its assessment of the roadmap that best addressed scientific priorities that have been developed in the past. The goal was to reconcile those goals with the reduced budget that would be available following the MSL cost overrun. The MATT team was directed to look at NASA-only resources, but with the understanding was that the proposed missions would be examined in other forums for potential international cooperation.
- The team was told to assume that NASA would have ~$700M for a 2016 mission and ~$1.3B for a 2018 mission. These figures were for discussion only since budgets have not been decided. [The first look at actual budget possibilities will likely come with the detailed Obama budget to be submitted in April. The President's proposed budgets generally give guidance on what agencies can expect for several years. These figures are also higher than my back of the envelope musings have suggested.]
- Previous MATT roadmap exercises have identified four high priority missions to follow the already approved MSL and MAVEN orbiter missions: A Mars Science Orbiter (MSO), a Mars Propector (mid-range) rover (MPR), a network mission, and MSR. [In the past and in this presentation, MATT has identified several possible sequences for doing these four missions. Here, I will discuss only the one that seemed most favored.]
- For 2016, MATT proposed that a descoped MSO mission fly. The mission would focus on atmospheric chemistry and climate studies as well as serve as a communications relay for landed Mars missions. A previous proposal to include a high resolution camera (0.3 - 1 m resolution) would be dropped to allow MSO to fit within the new budget realities. The planned MSO mission would follow up on the discovery of methane and other key trace gases in the Martian atmosphere.
- For 2018, MATT proposed the MPR mission. This would both explore a new site at Mars and maintain core Mars exploration competencies within NASA by keeping the development teams together. This rover has been discussed in the past as being solar powered. In this presentation, it was described as as "at least MER-class," but with with the ability to land within a 6 km target area of Mars to allow access to new sites.
- For 2020, MATT proposed a Mars network mission with four or more surface stations plus supporting meteoroligical measurements from an orbiter [that presumably could be MSO]
- For the 2020's, MATT proposed MSR plus a Scout mission.
JAXA, the Japanese space agency, also presented a concept for a mission between 2016 and 2020. The concepts seemed preliminary, but included an orbiter for meteorological studies and upper atmospher studies plus 1 to 3 landed network stations.
The presentations suggest a fruitful collaboration. One possible roadmap that would seem to meet both agencies' goals would be an 2016 ESA-led ExoMars rover with a NASA MSO orbiter. (If the Russians are included to provide the launch vehicle for ExoMars, US law may prohibit the launch of MSO by the Russians. This is, however, an area with which I'm not very familiar.) Then in 2018, NASA takes the lead with its own landed mission (presumably a rover) to which ESA contributes. Then in 2020, the two agencies plus possibly JAXA implement a network mission.
One concern I have is whether the NASA's budgets will support this aggressive of a roadmap while also funding the Jupiter Europa mission plus a sequence of New Frontiers and Discovery missions. This will be a question to be resolved not only by the details of the President's budget submission but also by the Decadal Survey review in progress. That review will take input from the entire planetary science community and prioritize missions (and by implication, allotment of the budget). Even if the MSO, MPR, and network missions don't all happen between 2016 and 2020, but are stretched out a few more years, it would still be an exciting and scientifically rich program.
And if NASA and ESA can manage to do MSR in the 2020s, I'll be delighted. Long time readers of this blog, however, know that I am a sceptic on this mission flying in my lifetime (which should give them until sometime in the late 2030s).
I should not have labeled these articles as excellent since I have no independent way of assessing them. They may in fact be excellent or have major problems. In the future, I will try not to apply adjectives to articles on issues that I don't have independent knowledge of. I will continue to provide links to major sources of information such as these articles.
For those interested in the history of MSL, a new presentation to the MEPAG meeting was just posted. Starting on page 7, it provides NASA's view of the history and current situation.
Monday, March 2, 2009
The Space Review published a brace of excellent articles on the problems experienced by the Mars Science Laboratory. The first deals with the technical challenges, the second with the budgetary challenges. Put together, they provide a good look at the types of problems that occur in large technology development projects.
Sunday, March 1, 2009
The timing for a new roadmap fits will with the schedule for the planetary Decadal Survey in progress that will lay out the priorities for mission for the next decade. MEPAG’s roadmap will serve as its input to the Decadal process and will have to compete with other good roadmaps from other disciplines. If my back of the envelope analysis of the budget options for the next decade were correct, there is not likely to be funds for as ambitious a campaign of missions as there has been for the last decade and a half. It could be that the Mars community may get just one moderate sized ($600M – 1B) and one small ($400 – 500M) mission. Contrast that with the Mars Global Surveyor orbiter (1997), Pathfinder (1997), Mars Odyssey (2001), Spirit and Opportunity (2004), the Mars Reconnaissance Orbiter (2006),
Traditionally, presentations from the MEPAG meetings are posted to the web a few days after the meeting. This time, one presentation has been posted ahead of the meeting on options for a Mars Science Orbiter in a post MSL overrun world. (Since this presentation is pre-meeting, it may change between the time of this blog and the meeting.) This presentation gives an idea of the types of belt tightening that the Mars community may look at across the roadmap. (See here for the most recent description of the previous MSO plan.) MSO has a high scientific priority since it would follow up on the discovery of short-lived methane in the Martian atmosphere, which could be the result of either on-going geologic activity or life.
NASA has planned a major science orbiter, MSO, for sometime in the mid-2010s for some time. The mission has had three goals, listed below in priority order. (Unless otherwise noted, quotes are from the presentation.) I also list the instrument(s) foreseen for each goal with cost estimates from a previous 2007 MSO report ( Report from the 2013 Mars Science Orbiter (MSO) Second Science Analysis Group.) The instrument costs and weights were estimates that may have changed by now.
1a. “Measure concentrations of a suite of trace gases of photochemical and radiative importance, including methane and potential molecular species related to characterizing its origins and loss (life cycle process); emphasis is on detection (bright source, limb path, spectral survey) and low-spatial resolution mapping.” This priority follows up on the detection of short-lived methane gas in the Martian atmosphere. Key goals are to nail down the amount of methane and other short-lived gases and their sources. Instrument: Solar occultation FTIR spectrometer (42 kg, $35M)
1b. “Measure those aspects of atmospheric state needed to constrain photochemical and dynamical (transport) models (T, dust) and to provide context for trace gas detections (dust, H2O); emphasis is on extending climate record used to validate climate simulations.” This goal both places the detection of trace gases in context and extends our knowledge of the Martian atmosphere. Instruments: Wide-angle camera (MARCI-like) (1 kg, $1M); Thermal-IR spectrometer (TES-like) (10 kg, $12M).
2. “The second priority is to improve temperature and water vapor measurement accuracy in the presence of dust and to better characterize atmospheric transport by making wind measurements and mapping temporal variations of key transported species (e.g., CO) and methane with good spatial resolution.” Instrument: Sub-millimeter spectrometer (35 kg, $35M)
3. “Investigate surface changes as recorded in surface properties and morphologies due to seasonal cycling, aeolian movement, mass wasting, small impact craters, action of present water.” This goal would be met through imaging of the Martian surface at 1 m or better resolution. Key imaging targets would be the polar layered terrain; aeolian features, gullies, avalanches, and dune movement; and formation of small impact craters over time. Instrument: 1 m camera (20 kg, $25M)
4. “HiRISE-class imaging (~30 cm resolution) for certification of future landing sites.” This would involve re-flying a camera with similar capabilities as the HiRISE instrument on the Mars Reconnaissance Orbiter. Instrument: (65 kg, $45M)
An additional goal, to carry a telecommunications package to communicate with future landers also was assumed. Also, only one high resolution camera would be flown. If budgets allowed, the HiRISE-class camera would replace the 1 m resolution-class camera.
The full up MSO mission was at one time estimated at over $1B in real year (i.e., inflation adjusted) dollars. Its cost in today’s dollars would probably be $800 – 900M if I’m doing my back of the envelope math right. A mission with those costs may no longer be affordable. The presentation offers two alternative missions.
MSO-min[imum] would fulfill only the 1a and 1b priorities (plus fly the telecommunications package.) MSO-lite would add priority 2. With either of these proposals, this becomes a strictly atmospheric (plus communications relay) mission. In this case, the orbit would be a high-inclination orbit (~74 degrees) optimized for repeated solar occultations of the atmosphere above all locations of the Martian surface (except the polar regions). The solar occultation FTIR spectrometer uses the bright light of the sun to detect trace gases in the atmosphere.
Both of these missions would forgo the high resolution camera (and the near polar orbit that would optimize global surface imaging at the expense of an optimized distribution of solar occulations). The issue for carrying a high resolution camera is not just the cost of the camera. The camera requires an ultra-stable platform (no jittering of the camera allowed!), precise pointing capabilities, significant data storage, and a hefty communications system to send the data back to Earth. The 2007 reported noted, “Unfortunately, achieving spatial resolution of 5-10 cm, under current state of the art, increases both mass and cost significantly, and largely becomes the only scientific goal for MSO. Also, spacecraft stability could become the limiting factor in resolution rather than the telescope.” Lower resolutions (even 1 M) bring similar problems.
The MEPAG presentation doesn’t list costs for MSO-min or MSO-lite. The MAVEN orbiter that will study the upper atmosphere of Mars, however, will cost $480M. It seems reasonable to assume that this represents a base cost estimate for an MSO mission with each additional goal met perhaps driving the cost incrementally higher.
With the discovery of methane in the Martian atmosphere, MSO is likely to be a high priority. MEPAG may have a difficult time deciding when to recommend its flight. NASA has said that it would like to contribute up to $400M to ESA’s 2016 ExoMars rover. If it does, it seems unlikely that it will have funds to fly MSO in the same launch opportunity. In that case, it may be 2018 or 2020 before MSO launches.