First, the highlights:
- "It is anticipated that approximately two to three Discovery investigations will be selected for 9-month Phase A concept studies through this AO. At the conclusion of these concept studies, it is planned that one Discovery investigation will be selected to continue into Phase B and subsequent mission phases."
- "Investigations may focus on any body in the Solar System, excluding the Earth and the Sun, and including Mars and the Moon. Investigations may not focus on extra-solar planetary systems."
- "Discovery Program investigations may propose the use of Advanced Stirling Radioisotope Generators (ASRGs) for missions enabled by radioisotope power systems."
- "Investigations are capped at a life-cycle cost of $425M (FY10), excluding standard launch services and, if required, ASRGs. Lower-cost investigations are encouraged."
- Selection for competitive Phase A studies July 2010 (target); Down-selection November 2011(target); Launch date NLT December 31, 2016
Three key departures from past Discovery program selections. First, missions to any place in the solar system can be proposed. In the past, Mars had been explicitly excluded. Second, the option to use radioisotope (ASRG) power systems opens up missions to the outer solar system and/or missions where solar panels would have been difficult. Third, while the budget for the mission has not increased, I believe that this is the first time that NASA is not including the cost of the launch vehicle within proposer's costs. (If anyone knows differently, please add a comment.)
Put together, these changes open up a much wider range of mission possibilities than we've had in the past. It will be very interesting to see which missions get selected in a little over a year for more in-depth study.
Resources: NASA intends to release a Discovery Program Draft AO