1 day / second

0.5 AU

951 Gaspra

Asteroid

An irregularly shaped, 19 x 12 x 11 kilometer S-type asteroid discovered in 1916 that became the first asteroid ever photographed up close when the Galileo spacecraft flew past it in 1991.

Key Facts

orbital regime

Asteroid Belt

learn more

Wikipedia

mass

2.5000e+15 kg

radius

6.1 km

hill radius

2,045.341 km

semi-major axis

2.21 AU

eccentricity

0.173

inclination

4.106º

longitude of the ascending node

252.989º

argument of periapsis

129.955º

orbital period

3.285 years

discovery date

July 30, 1916

discovered by

Grigory Neujmin at Simeiz Observatory

name origins

Named after Gaspra, a Black Sea resort in Crimea

dimensions

12.2 kilometers in diameter

density

2.7 g/cm³

albedo

0.22

material composition

S-type asteroid (silicaceous/stony composition)
Spacecraft Visits
Galileo

Flyby

NASA

Launched in 1989, visited in 1991

On October 29, 1991, Galileo became the first spacecraft to encounter an asteroid when it flew within 1,600 kilometers of Gaspra, capturing detailed images of its irregular, cratered surface.

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