85 Io

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

C. H. F. Peters

Discovery date

19 September 1865

Pronunciation

/ ˈ aɪ . oʊ /

Named after

Io

Alternative designations

A899 LA · A899 UA

Minor planet category

main-belt · ( middle ) , Eunomian interloper

Adjectives

Ionian / aɪ ˈ oʊ n i ə n /

Observation arc

151.35 yr (55,280 days)

Aphelion

3.1679 AU

Perihelion

2.1379 AU

Semi major axis

2.6529 AU

Orbital period sidereal

4.32 yr (1,578 days)

Mean anomaly

83.678 °

Mean motion

0° 13 41.16 / day

Inclination

11.961°

Longitude of ascending node

203.12°

Argument of perihelion

123.11°

Dimensions

180 × 160 × 160 km

via Wikipedia infobox

Wikidata facts

Diameter

154.79

Orbital period

1578.382625429113

Image

85Io (Lightcurve Inversion).png

via Wikidata · CC0