NASA Headquarters, Washington, DC

November 12, 1998


In the first step of a two-step process, NASA has selected five proposals for detailed study as candidates for the next missions in the Agency's Discovery Program of lower-cost, highly focused scientific spacecraft.

In a unique step for this program, NASA has also decided to fund a co-investigator to provide part of an instrument to study the interaction between the solar wind and the atmosphere of Mars. It is scheduled to fly aboard the European Space Agency's Mars Express spacecraft in 2003. NASA plans to consider such investigations, categorized as "Missions of Opportunity," in all future Discovery and Explorer program Announcements of Opportunity.

The mission proposals selected for further study would send spacecraft to orbit Mercury, return samples of the two small moons of Mars to Earth, study the interior of Jupiter, excavate and study material from deep inside a comet nucleus and investigate the middle atmosphere of Venus.

The five missions were among 26 full mission proposals submitted to NASA. "The degree of innovation in these proposals climbs higher each time we solicit ideas," said Dr. Ed Weiler, acting associate administrator for space science at NASA Headquarters. "Deciding which one or two of these exciting finalists will be fully developed will be a very difficult choice -- any one of them promises to return unique insights into our Solar System. Meanwhile, the solar wind instrument will fill in some critical gaps in our understanding of the history of water on Mars."

Following detailed mission concept studies, which are due for submission by March 31, 1999, NASA intends to select one or two of the mission proposals in June 1999 for full development as the seventh and possibly eighth Discovery Program flights.

The selected proposals were judged to have the best science value among 30 total proposals submitted to NASA in response to the Discovery Announcement of Opportunity (AO-98-OSS-04) issued on March 31, 1998. Each will now receive $375,000 to conduct a four- month implementation feasibility study focused on cost, management and technical plans, including small business involvement and educational outreach. As stated in the AO, the initial mission cost estimates will not be allowed to grow by more than 20 percent in the detailed final proposals.

The selected proposals are: