Friday, October 24, 2008

What Next for Mars?

With the Mars Science Laboratory (MSL) and ExoMars funding and schedules up in the air, it may seem too soon to think about what NASA missions should follow MSL. However, these projects require long development times and need to be fit with other projects into NASA’s future funding profiles. It also takes years to build consensus across the Mars and planetary science communities. With these issues in mind, NASA has a Mars Architecture Tiger Team (MATT) examining the options and recommending a sequence of missions for post 2016. (http://mepag.jpl.nasa.gov/meeting/sep-08/Christensen_MATT2_for_MEPAG.pdf)

The MAVEN aeronomy and upper atmosphere Scout mission is currently scheduled to follow MSL in 2013. However, its schedule and even continuation may be in doubt if its funding becomes required to enable the completion of MSL. (Based on past mission funding profiles, I expect that MAVEN’s peak funding years are 2011 and 2012, too late to provide a piggy bank to directly fund the MSL overruns. The MAVEN funding may be needed, however, to pay back other NASA missions that are “taxed” in the next year or two to pay for the MSL cost increase.) For the rest of this post, I will assume that MAVEN will fly on schedule.

The highest priority follow on mission (and has been for at least 20 years) would be a Mars Sample Return (MSR) mission. I don’t think this mission is likely to fly before the late 2020s (the desire is for the early to mid 2020s). The cost and technology development make this mission, in my opinion, unlikely in the nearer timeframe. It would also be difficult to develop the proposed outer planets Flagship mission (destination Jupiter/Europa or Saturn/Titan) in parallel.

The rest of this post, therefore, will focus on the other three missions that MATT has identified. MATT identifies the following science goals for post MSL related to the theme, “Seeking Habitable Environments” (quoted from the MATT presentation):

-Investigate the physics, chemistry, and dynamics of the upper atmosphere, the effects of solar wind and radiation, and the escape of volatiles to space (MAVEN) - 2013
- Explore a diversity of surface environments using rovers with sample acquisition, analysis, and caching capabilities (Mars Prospector Rover (MPR) also called the mid-range rover) - 2016
- Determine the composition and structure of the current atmosphere (Mars Science Orbiter (MSO)) - 2018
- Investigate the deep interior using a network of landed geophysical experiments (Network Lander) – 2020 (if MSR is delayed past 2020)
- Return carefully selected and well-documented samples from a potentially habitable environment to Earth for detailed analysis (MSR)

Even without MSR, this is an ambitious, varied, and robust set of missions for future exploration of Mars. MATT has spent considerable time thinking about the sequence of the missions. From a science point of view, flying MSO in 2016 makes sense. It would provide continuity of climate observations with the current Mars Reconnaissance Orbiter (http://mars.jpl.nasa.gov/mro/) and data relay for follow on missions. MATT recommends the MPR rover ahead MSO to ensure that JPL’s rover team remains intact. MSO needs to fly before NET both to provide data relay (the small NET landers presumably would not have high bandwidth direct to Earth communication capabilities) and global climate measurements to put NET’s meteorological measurements in context. Should MSR be able to fly in the early 2020’s MATT recommends that NET follow MSR.

My next post will discuss the MPR rover in more detail and an alternative roadmap that I think should be considered. The rest of this post reproduces summaries of the NET and MSO missions from the latest MATT presentation:

Mars Science Orbiter (MSO): Long-lived Science Orbiter Providing Atmospheric Remote Sensing and Mission Support
–Extend atmospheric and seasonal surface climate baseline through next decade
•Provide improved and new (e.g., winds) profiling capabilities
–Provide extensive global, diurnal and seasonal survey of key trace gases, including carbon-bearing compounds with implications for interior bio/geochemical processes
•Methane and higher order hydrocarbons
•Photochemical products, isotopes (CO, NO, etc.)
–Synergistic with Network for both relay and atmospheric science
–Synergistic (lower atmosphere) with 2013 Scout (upper atmosphere)
–Provide telecom, site characterization and atmospheric monitoring for the future

Network (NET): ≥ 4 Landed Stations Arrayed in a Seismic Network
– Characterize interior structure, composition and processes
– Elucidate evolution of the interior over time and role in Mars climate history
– Advance the comparative study of planetary formation and evolution
– Characterize local meteorology and provide baseline for orbital climate measurements
– Highest priority after sample return in NRC reports / Decadal Survey

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