With this amendment to ROSES-2005, NASA announces a new proposal
opportunity -- the Mars Exploration Rovers (MER) Participating Scientists
program. Notices of Intent to propose are due June 7, 2005, and proposals
are due July 19, 2005.

On or about May 12, 2005, Amendment No. 12 to NASA Research Announcement
"Research Opportunities in Space and Earth Sciences" (NNH05ZDA001N) will be
posted on its homepage Web site at http://nspires.nasaprs.com/ (select
"Solicitations" then "Open Solicitations" then "NNH05ZDA001N").

This amendment establishes a new Program Element B.22 in Appendix B
entitled "Mars Exploration Rovers (MER) Participating Scientists." This
new program element solicits proposals for science investigations that
enhance the science data return from the Mars Exploration Rovers by
broadening participation in the mission, augmenting the existing MER
science team to include new investigations, and maximizing the contribution
of the Mars Exploration Rovers to the future exploration and scientific
understanding of Mars. The MER Participating Scientists program will also
provide additional scientists to participate in daily mission operations of
the Mars Exploration Rovers. Notices of Intent to propose are due June 7,
2005, and proposals are due July 19, 2005.

Further information about this new program element is available from Dr.
Curt Niebur, Solar System Division, Science Mission Directorate, NASA
Headquarters, Washington, DC 20546-0001; Telephone: (202)
358-0390; E-mail: Curt.Niebur@....