Tuesday, January 4, 2011

Compelling Decadal Survey Missions

With the long holidays behind us, I'll restart my selection of the five missions under consideration by the Decadal Survey.  My criteria for selection has been that the missions have, in my opinion, the greatest chance for fundamentally changing our understanding of the solar system or our own home planet.  This list and the analysis presented is intended to stimulate thinking rather than to persuade you that my list is right.  Ray at Vision Restoration has been presenting his own list based on the goals of overall exploration and development of space.

I've been using this series to go through the Survey's mission concept studies to understand some of the issues inherent in planning a roadmap for the coming decade and to explore individual mission concepts.  To date, my list has included:

  • 1st priority: Missions leading to a Mars sample return: Mars Trace Gas Orbiter, MAX-C and ExoMars rover, and technology development for the missions that would return the cached samples to Earth
  • 2nd priority: A Venus mission (lander, balloon, or orbiter) that would help us understand how Venus diverged so dramatically from Earth even though the planets were apparently more similar early in their history.  NASA's mission might be part of a series of international missions
  • 3rd and 4th priorities: Advance the exploration of ice-ocean moons as potential habitats.  The Jupiter Europa Orbiter (JEO) would, in my opinion, provide the greatest return for the dollars spent but hinges on the budget allowing a second large flagship mission (MAX-C would be the first) in a single decade, the technology being ready to allow extended operation in the high radiation at Europa, and sufficient plutonium supplies to power the spacecraft. As my fourth priority, a Discovery or New Frontiers class mission to continue the exploration of Enceladus or Titan.  If JEO doesn't fly, then my priorities would change to put continued exploration of Enceladus and Titan as the third priority and a small flagship class Ganymede orbiter with flybys of Europa and Callisto as my fourth priority.

This weekend, I'll begin looking at three missions that are my candidates for the fifth priority: Mars geophysical network, a Neptune-Triton mission, and a comet sample return.

I'll close this blog with a relisting of the missions under consideration by the Decadal Survey.  Most of the mission concepts come with specific price estimates, but as one report states given the limited time for analysis of each mission, "it would be appropriate to thing of costs at relative levels of ~$1.0B, ~$1.5B, ~$2.0B, etc."  These studies included both principal investigator (spacecraft, instruments, operations, etc) and launch costs.   With that in mind, here is the list of missions broken into three cost bins:

Approximately New Frontiers (<$1.2B estimate in study)

  • Lunar Geophysical Network (4 landers)
  • Trojan Tour and Rendezvous 
  • Lunar Polar Volatiles Explorer 
  • Chiron Orbiter Mission 
  • Saturn Atmospheric Probe 
  • Mars Polar Climate mission concepts
  • Io Observer 
  • Mars Geophysical Network (2 landers)  

In the FY15 dollars used for these studies, a New Frontiers mission would cost around $1.05B.

Smaller Flagship Missions ($1.3-$1.6B estimate)

  • Venus Intrepid Tessera Lander
  • Titan Lake Probe (4 options) 
  •  Mars Sample Return Orbiter 
  • Ganymede Orbiter 
  • Enceladus multiflyby 
  • Mercury Lander (mid-range option) 
  • Neptune-Triton-KBO or minimum Neptune orbiter 
  • Venus Climate Mission Enceladus Orbiter  

Larger Flagship Missions (>$1.9B estimate)

  • Uranus Orbiter with probe 
  • Venus Mobile Explorer 
  • Mars MAX-C Caching Rover 
  • Mars 2018 Sky Crane Lander 
  • Mars Sample Return Lander & Ascent Vehicle 
  • Jupiter Europa Orbiter 
  • Titan Saturn System Mission  

These mission bins are not necessarily fixed. Several small flagship missions have larger flagship mission alternatives, for example.  In addition, there are proposals for Discovery missionsfor a Titan Lake Lander, a simple multi-flyby mission to Titan and Enceladus, and an Io Observer.  By reducing mission goals and capabilities, significant costs can be saved.  However, it is possible that (1) these missions might no longer be as compelling compared to other Discovery mission proposals and (2) the proposing PI's may be optimistic in how cheaply these missions can be implemented.  (Editorial note:  I personally like these Discovery mission concepts, and hope that neither of these caveats apply.)

No comments:

Post a Comment