When Congress completed the fiscal year 2014 omnibus spending bill last month, the report accompanying the bill included some specific language regarding NASA’s Discovery program of relatively small planetary science missions. That report directed NASA to issue an announcement of opportunity (AO) for the Discovery program’s next round “no later than May 1, 2014,” and select one or more missions by September 2015. That language was an effort by Congress to encourage NASA to increase the tempo of Discovery-class missions, a topic of concern among planetary scientists.
On Wednesday, NASA issued a synopsis of that planned Discovery solicitation, indicating that it will miss the deadline in the omnibus report by several months. Under NASA’s current plan, it will release a draft version of the AO in May and seek comments from the community. NASA will release the final AO in September, with proposals due 90 days later. NASA will award “Phase A” studies of potential missions—in effect, a selection of finalists—in May 2015, with the final selection to come by October 2016. That will be more than a year after the language in the Congressional report, and more than four years after NASA selected the previous Discovery mission, the InSight Mars lander.
The delay in releasing the AO, though, is not surprising. Shortly after the omnibus spending bill passed last month, Jim Green, director of NASA’s planetary sciences division, told a meeting of the Planetary Science Subcommittee of the NASA Advisory Council that the schedule in the congressional report wasn’t realistic. He said that releasing the AO so quickly “would catch everyone by surprise.” Instead, he said his office was working on a revised schedule that would release the AO before the end of the fiscal year, which the schedule released Wednesday maintains.
The synopsis contained few surprises about the content and scope of the upcoming solicitation. The missions proposed must fit within a cost cap of $450 million (in 2015 dollars), including a 25% cost reserve; launch vehicle costs, though, are not included in that cap. NASA is also willing to provide some advanced technologies for proposed missions, such as an ion propulsion system and heat shield, and may require the missions to include a laser communications system.
However, proposals cannot include the use of radioisotope power systems, since the fueling of such systems “cannot be met in time for the expected launch window” of these missions, which is no later than the end of 2021. NASA has previously offered an Advanced Stirling Radioisotope Generator (ASRG), a more efficient version of the radiosiotope thermoelectric generators (RTGs) used on other NASA missions, and two of the three finalists for the previous Discovery round planned to use ASRGs. But InSight, the winning mission, is solar powered, and last November NASA stopped plans to procure ASRGs in a money-saving move, since there were no missions on the books to use them.