239 Adrastea

Picture of the Day · NASA

Pathfinder on Mars

2026-07-04

On July 4th, 1997, using its own array of fireworks, a parachute, and a cocoon of airbags, the Mars Pathfinder spacecraft bounced like a giant beach ball at least 15 times before it came to rest on the surface of Mars at 10:07 AM Pacific Daylight Time. After its then novel airbag-assisted landing sequence was completed, Pathfinder transmitted this color mosaic to mission operators on Earth. In the scene from another world, the Mars Sojourner robot rover is visible in the foreground, crouched on top of the unfolded Pathfinder. About the size of a large house cat, the six-wheeled, solar-powered Sojourner became the first successful Martian rover. Surrounding Pathfinder are deflated airbags and the rock-strewn terrain of the Ares Vallis floodplain. In the distance Martian hills appear against a dusty brownish sky. The Pathfinder lander was subsequently renamed the Carl Sagan Memorial Station.

via NASA APOD

Key facts

Discovered by

Johann Palisa

Discovery date

18 August 1884

Pronunciation

/ æ d r ə ˈ s t iː ə /

Named after

Adrasteia

Alternative designations

A884 QA, 1915 TD, 1955 MK 1 , 1956 UJ

Minor planet category

Main belt

Observation arc

131.66 yr (48,087 d)

Aphelion

3.66279 AU (547.946 Gm )

Perihelion

2.2695 AU (339.51 Gm)

Semi major axis

2.96616 AU (443.731 Gm)

Orbital period sidereal

5.11 yr (1,865.9 d)

Average orbital speed

17.25 km/s

Mean anomaly

233.617 °

Mean motion

0° 11 34.584 / day

Inclination

6.1746°

Longitude of ascending node

180.634°

Argument of perihelion

210.15°

Dimensions

41.52 ± 1.4 km

via Wikipedia infobox

Wikidata facts

Instance of

asteroid

Named after

Adrasteia

Followed by

Q148915

Follows

238 Hypatia

Parent body

Sun

Minor-planet group

asteroid belt

Diameter

37.609

Orbital period

1865.423378002167

via Wikidata · CC0