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
- T. Gehrels
- Discovery site
- Palomar Obs.
- Discovery date
- 20 September 1973
- Named after
- Pala (Indian reservation)
- Alternative designations
- 1973 SE
- Minor planet category
- main-belt · ( outer ) , background
- Observation arc
- 43.52 yr (15,895 days)
- Aphelion
- 4.5807 AU
- Perihelion
- 2.0148 AU
- Semi major axis
- 3.2978 AU
- Orbital period sidereal
- 5.99 yr (2,187 days)
- Mean anomaly
- 165.04 °
- Mean motion
- 0° 9 52.56 / day
- Inclination
- 19.192°
- Longitude of ascending node
- 352.31°
- Argument of perihelion
- 20.092°
- Dimensions
- 8.2 km
- Absolute magnitude h
- 14.3 · 14.6
via Wikipedia infobox
Wikidata facts
- Instance of
- asteroid
- Followed by
- 1922 Zulu
- Follows
- 1920 Sarmiento
- Parent body
- Sun
- Orbital period
- 2199.697924886383
Show 15 more facts
- discoverer or inventor
- Tom Gehrels
- site of astronomical discovery
- Palomar Observatory
- provisional designation
- 1973 SE
- time of discovery or invention
- 1973-09-20
- orbital inclination
- 19.07166415926933
- orbital eccentricity
- 0.3838063161439298
- periapsis
- 2.039671939552809
- apoapsis
- 4.580558007592293
- semi-major axis of an orbit
- 3.310114973572551
- mean anomaly
- 296.5820440003242
- longitude of ascending node
- 351.8274640117564
- argument of periapsis
- 20.45751555479288
- absolute magnitude
- 14.86
- time of periapsis
- 2461388.000961703
- epoch
- November 21, 2025
Sources (2)
via Wikidata · CC0
~2 min read
Encyclopedic overview
1921 Pala, provisional designation 1973 SE is a background asteroid in an unstable orbit located in the outer region of asteroid belt, approximately 8.2 kilometers in diameter. It is one of very few bodies located in the 2 : 1 mean motion resonance with Jupiter. It was discovered by Dutch–American astronomer Tom Gehrels at Palomar Observatory on 20 September 1973.
Orbit and characterization
Excerpted from Wikipedia’s “1921 Pala” article, available under the CC BY-SA 4.0 licence.