Q136642

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

K. Reinmuth

Discovery site

Heidelberg Obs.

Discovery date

29 September 1929

Pronunciation

/ θ ɪ ˈ s eɪ l i ə /

Named after

Thessaly (Greek region)

Alternative designations

1929 SF · 1931 BB

Minor planet category

main-belt · ( outer ) , background

Observation arc

87.76 yr (32,056 days)

Aphelion

3.4488 AU

Perihelion

2.8975 AU

Semi major axis

3.1732 AU

Orbital period sidereal

5.65 yr (2,065 days)

Mean anomaly

213.02 °

Mean motion

0° 10 27.84 / day

Inclination

9.3913°

Longitude of ascending node

72.567°

Argument of perihelion

309.20°

Dimensions

21.498 ± 0.184 km

via Wikipedia infobox

Wikidata facts

Diameter

21.498

Orbital period

2059.320900219811

via Wikidata · CC0