Thursday, February 20, 2014

Boundaries for the Next Discovery Mission Selection

In my post a couple of weeks ago on the selection of NASA’s next low cost planetary mission, I said that the conditions NASA imposed on scientists proposing missions would determine much of what kind of missions scientists could impose.

Yesterday, NASA released a preview for the next competition.  There are some important innovations and a major limitation.

NASA will accept proposals to study any solar system body except the sun and the Earth.  Scientists cannot propose missions to study planetary systems around other stars (NASA astrophysics program funds these missions.)

NASA announced that the budget for the spacecraft, instruments, and data analysis (the Principal Investigator (PI) budget) would be $450M (FY15 dollars).   This is a small increase from the last competition’s PI budget of $425M, and by itself would not keep up with inflation. 

Outside of the PI’s budget, NASA will pay for the cost of the mission launch.  For the first time, NASA will pay for the cost of the mission’s operation outside of the PI budget.  In past competitions, missions with long flight times, and hence high operations costs, were at a disadvantage to missions with low operations costs.  This appears to be an effort to equalize operations costs.  Missions that would benefit are any with flight times of several years compared to the weeks or months to reach Venus, the moon, or Mars.  With operations costs not counted against the PI’s budget, the new competition probably keeps up with inflation compared to the previous competition.  (NASA’s announcement does emphasize that the operations costs projected for a mission must be ‘reasonable’.)

The major limitation for this competition is that NASA will not provide a radioisotope power system for this competition.  While recent NASA presentations suggests it has sufficient plutonium-238 fuel to support a Discovery mission, that fuel could not be prepared in time to meet the expect launch date for this competition.  As a result, any mission that cannot use solar power is effectively eliminated.  This would include missions beyond Jupiter, to the permanently shadowed lunar polar craters, or where large solar panels just won’t work like for a mission that would make multiple landings on a comet (see this description of the CHOPPER mission proposed for the last competition).

NASA traditionally offers scientists various technologies at the space agency’s cost that it would like to see tested in space.  For this competition, NASA says it is considering providing a version of the NASA Evolutionary Xenon Thruster (NEXT) ion propulsion engine as well as heat shield technology for missions that would send a probe into planetary atmosphere.  These former would benefit missions that would require large amounts of thrust such as main belt asteroid missions or comet rendezvous missions.  The latter would benefit missions such as Venus atmospheric probes.

NASA also is considering requiring proposals to include carrying its Deep Space Laser Communications (DSLO) package.  This technology was tested on the LADEE mission currently orbiting the moon and showed that lasers could return much larger volumes of data than traditional radio systems.  NASA would now like to try this technology from a spacecraft in deep space.  Missions with low data rates such as Venus atmospheric probes probably would see little benefit from the DSLO system.  Missions with lots of imaging data such as Venus radar mappers or Io multi-flyby missions would make good use of the DSLO system.

One other new requirement is a limitation on how much of the cost of instruments foreign space agencies can contribute.  NASA has had a limitation that foreign governments could not contribute more than one-third the cost of the total mission.  That cap now also applies to the contribution to the cost of the science payload, too.  This appears to be a way of preventing a proposal team from minimizing its PI costs by filling most of the payload with instruments paid for by other governments.  NASA apparently wants US planetary missions to provide opportunities for US scientists to fly their instruments.

All in all, this looks to be a nice opportunity that keeps the Discovery program on track to continue to support innovative missions to a variety of destinations in the solar system.

Key dates (subject to change)

May 2014 – release of draft Announcement of Opportunity with details for proposers

September 2014 – release of final Announcement of Opportunity

December 2014 – proposals due

May 2105 – selection of two to three finalists for further study

October 2016 – selection of winning mission

December 2021 – launch by this date


  1. In considering the cost cap, it's important to keep in mind that $425M in FY10 dollars is $470M in FY15 dollars (according to the NASA New Start Inflation Index). So the $450M (FY15) cost cap sort of assumes a Phase E cost of at least $20M (FY15). Missions with Phase E's exceeding $20M are, therefore, not discouraged.

  2. Saw this GREAT Infographic on where are all active space probes are in solar system.

    Found it online at Yahoo.


  3. So I guess its bye bye Titan, once again. I'm so sick of Mars.

  4. Anon 2 - No Titan this time, but two hopeful tidbits. First, NASA plans to offer an MMRTG plutonium power source for all subsequent Discovery competitions (so the lack of one this time is just bad timing in terms of ramping up production). Also, the latest budget proposal shows the Discovery program ramping up to have a budget that would allow a selection every two years by the end of this decade.