The Compton Gamma Ray Observatory launches from the space shuttle Atlantis.
The workshop on Towards Other Planetary Systems (TOPS): A Technology Needs Assessment is held at LPI. Convened by David Black and Kenji Nishioka, the purpose of the workshop is to identify and document key technology issues associated with the TOPS program in general, and with some of the candidate observational facilities specifically.
The International Conference on Asteroids, Comets, Meteors 1991 is held in Flagstaff, Arizona. The LPI provides co-sponsorship and administrative, logistical, and publications support.
The workshop on Martian Surface and Atmosphere Through Time (MSATT) is held in Boulder, Colorado, signaling the start of the MSATT Study Project.
Galileo makes the first spacecraft flyby of an asteroid, passing within 16,200 km of Gaspra.
LPI hosts a Girl Scout Science Education Workshop on Youth and Space: A Science Experiment. Co-sponsors include the JSC Astronomy Club and the NASA Johnson Space Center.