On this day in space! Oct. 29, 1991: NASA's Galileo spacecraft flies by asteroid Gaspra and snaps amazing photos while flying at 18,000 mph

Automatically curated summary from Space.com.

On October 29, 1991, NASA's Galileo spacecraft performed the first-ever asteroid flyby, passing asteroid Gaspra while en route to Jupiter. Traveling at approximately 18,000 mph (about 5 miles per second), Galileo came within roughly 990 miles of the asteroid. The spacecraft captured detailed images and utilized a Near-Infrared Mapping Spectrometer to examine Gaspra's composition and physical structure, revealing an irregular, cratered shape covered in dust and rubble. However, because Galileo remained too far away for Gaspra's gravity to influence its path, the probe was unable to measure the asteroid's mass.

Context and limitations

The source notes that Galileo was unable to determine Gaspra's mass during the flyby because the spacecraft was too far away to be affected by the asteroid's gravity.