At the just completed Lunar and Planetary Science Conference Steve Squyres provided the most complete explanation and update of the Decadal Survey I've seen yet. (Go to the Decadal Survey webpage, and look for 'View the Presentation given by Decadal Chair Steve Squyres to the LPSC on the status of the study' about a quarter of the way down the page. This is a Java link, so I can't provide a normal link.)
His presentation discusses the scope of the Survey, which will prioritize all Flagship and New Frontiers missions. If New Frontiers missions are prioritized by rank as opposed to just identifying a candidate pool of targets, this will be change in how these missions are selected. The last Decadal Survey selected a pool of (if memory serves me correctly) four missions that was latter expanded to six to eight missions. Any target within the pool -- which ranged across the solar system -- was an allowable target. Squyres' slide suggests that instead, this Survey may actually designate which specific targets are priority #1, #2, and so forth.
Discovery missions will continue to be selected by competition, but the science goals by which they will be selected will be identified by the Survey. Only missions that have received formal budgetary new starts and therefore are in development are exempt from review (these are Juno [Jupiter interior and atmosphere], GRAIL [lunar gravity], Mars Science Laboratory rover, LADEE [lunar atmosphere], MAVEN [Mars upper atmosphere]). All other missions including the Mars Trace Gas orbiter and the Jupiter Europa Orbiter are subject to Survey review and prioritization. A key requirement is that the recommended list be able to be implemented within expected budgets. NASA has made it clear that it will use the Survey's prioritization as its priorities.
Squyres included a schedule for completing the survey:
- 1st- 2nd Quarter Final Panel meetings, Panel reports finalized
- 2nd-3rd Quarter Prioritization and drafting of survey report
- 4th Quarter Draft survey report to reviewers, Report revised
- 1st Quarter Report approved, NASA, NSF, OMB and Congress briefed and report released (prepublication-format)
- 3rd Quarter Printed report released
A couple of weeks ago, the subscription-only journal Nature had an article discussing the Astronomy Decadal Survey, which is in progress but somewhat ahead of the Planetary Decadal Survey. Nature held a round table with several prominent astronomers who were not members of that Survey. The participants emphasized the importance of a 'narrative' to provide a story behind the recommendations of a Survey. The search for life in the universe and understanding the origins of the universe were discussed as possible astronomy narratives. (As a side note, a strawman poll of the Nature discussion participants gave priority to the Large Synoptic Survey Telescope, the Giant Segmented Telescope, the Terrestrial Planet Finder, and the Constellation-X Observatory/International X-ray Observatory.)
If the planetary survey selects a narrative, then prioritizing the larger Flagship and New Frontiers class missions makes sense.
I don't think it's hard to predict a likely Planetary Survey narrative: The search for possible habitats for life, past or present, in the solar system. This would give priority to missions to Mars, Europa, Titan, and Enceladus. Venus, Ganymede, and Callisto might gain supporting roles as worlds that help us understand the evolution of terrestrial planets and icy moons. If this becomes the narrative, the target worlds are easy to predict. What is harder to predict is how the Survey will recommend that dollars and therefore mission resources be divided between them.
Appendix: This is the list of missions that the Survey is considering for the next decade (from Squyres' presentation). The institution performing the analysis of each mission is also given: Goddard Spaceflight Center, the Jet Propulsion Laboratory, the John Hopkins Applied Physics Laboratory, and the Marshall Spaceflight Center.
- SAGE (NASA New Frontiers 3 Candidate)
- Venus Mobile Explorer (GSFC)
- Venus Tessera Lander (GSFC)
- Venus Climate Mission (GSFC)
- Moonrise (NASA New Frontiers 3 Candidate)
- Lunar Polar Volatiles Lander (APL)
- Lunar Network Mission (MSFC)
- Mars Trace Gas Orbiter (JPL)
- Mars Polar Mission (JPL)
- Mars Network Mission (JPL)
- Mars Sample Return (JPL):
- Mars Astrobiology Explorer with Cacheing
- Mars Sample Return Lander
- Mars Sample Return Orbiter
- Europa Flagship Mission (JPL)
- Io Mission (JPL)
- Ganymede Mission (JPL)
- Saturn Probe (JPL)
- Titan Flagship Mission (JPL)
- Titan Lake Lander (JPL)
- Enceladus Mission (JPL)
- Uranus System Mission (APL)
- Neptune System Mission (JPL)
- OSIRIS REX (NASA New Frontiers 3 Candidate)
- Main Belt Asteroid Lander (APL)
- Chiron Orbiter (GSFC)
- Trojan Asteroid Tour (APL)
- Comet Surface Sample Return (APL)
- NEO target study. (Assess NEO targets that can be reached with an electric propulsion spacecraft.)
- Reactor-Based thermoelectric generator technology study.
- Saturn Ring Observer technology study.
- Comet cryogenic sample return technology study.
- NSF-funded ground-based telescopes
- Technology development for future NASA
- planetary missions
- The NASA and NSF planetary R&A programs
- Public Outreach