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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
- George Henry Peters
- Discovery site
- Washington, D.C.
- Discovery date
- 21 November 1921
- Pronunciation
- / æ n ə ˈ k ɒ s t i ə /
- Alternative designations
- 1921 W19
- Observation arc
- 87.01 yr (31782 days)
- Aphelion
- 3.2953 AU (492.97 Gm )
- Perihelion
- 2.1842 AU (326.75 Gm)
- Semi major axis
- 2.7397 AU (409.85 Gm)
- Orbital period sidereal
- 4.53 yr (1656.4 d )
- Mean anomaly
- 317.515 °
- Mean motion
- 0° 13 2.424 / day
- Inclination
- 15.905°
- Longitude of ascending node
- 285.817°
- Argument of perihelion
- 70.143°
- Mean radius
- 43.095 ± 0.8 km
- Synodic rotation period
- 20.117 h (0.8382 d )
- Geometric albedo
- 0.1723 ± 0.006
via Wikipedia infobox
Wikidata facts
- Instance of
- asteroid
- Followed by
- 981 Martina
- Follows
- 979 Ilsewa
- Parent body
- Sun
- Minor-planet group
- asteroid belt
- Diameter
- 74.679
- Orbital period
- 1657.836885294073
Show 19 more facts
- discoverer or inventor
- George Henry Peters
- site of astronomical discovery
- Old Naval Observatory
- provisional designation
- A921 WG
- time of discovery or invention
- 1921-11-21
- orbital inclination
- 15.89626299729694
- Commons category
- 980 Anacostia
- albedo
- 0.229
- rotation period
- 20.117
- asteroid spectral type
- L-type asteroid
- absolute magnitude
- 7.89
- orbital eccentricity
- 0.2015783832960381
- semi-major axis of an orbit
- 2.741335861472079
- periapsis
- 2.188741810445085
- apoapsis
- 3.293929912499072
- longitude of ascending node
- 285.7619263681004
- argument of periapsis
- 69.76015121260747
- mean anomaly
- 336.6984428576083
- time of periapsis
- 2461107.8060580986
- epoch
- November 21, 2025
Sources (2)
via Wikidata · CC0
~1 min read
Encyclopedic overview
980 Anacostia is a minor planet orbiting the Sun that was discovered by American astronomer George Henry Peters on 21 November 1921. The name recognizes the Anacostia River and an historic neighborhood of the same name in the city of Washington, D.C.
Measurements using the adaptive optics system at the W. M. Keck Observatory give a diameter of 70 ± 6 km. This is 23% smaller than the diameter estimated from the IRAS observatory data. The size ratio between the major and minor axes is 1.09.
Excerpted from Wikipedia’s “980 Anacostia” article, available under the CC BY-SA 4.0 licence.