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
- S. Belyavskyj
- Discovery site
- Simeiz Obs.
- Discovery date
- 27 March 1916
- Pronunciation
- / æ l ˈ t oʊ n ə /
- Named after
- German city of Altona
- Alternative designations
- A916 FG · A923 RP, 1916 Σ24 · 1923 RP
- Minor planet category
- main-belt · ( outer ) , background
- Observation arc
- 102.52 yr (37,446 d)
- Aphelion
- 3.3753 AU
- Perihelion
- 2.6234 AU
- Semi major axis
- 2.9994 AU
- Orbital period sidereal
- 5.19 yr (1,897 d)
- Mean anomaly
- 318.70 °
- Mean motion
- 0° 11 22.92 / day
- Inclination
- 15.546°
- Longitude of ascending node
- 121.13°
- Argument of perihelion
- 134.95°
- Dimensions
- 80.0 km × 80.0 km
via Wikipedia infobox
Wikidata facts
- Instance of
- asteroid
- Named after
- Altona
- Followed by
- Q157429
- Follows
- 849 Ara
- Parent body
- Sun
- Minor-planet group
- asteroid belt
- Diameter
- 80.9
- Orbital period
- 1894.997677239875
Show 17 more facts
- discoverer or inventor
- Sergey Belyavsky
- site of astronomical discovery
- Simeiz Observatory
- provisional designation
- A916 FG
- time of discovery or invention
- 1916-03-27
- orbital inclination
- 15.52954687897694
- albedo
- 0.039
- rotation period
- 11.1913
- absolute magnitude
- 9.69
- orbital eccentricity
- 0.1301515491963192
- semi-major axis of an orbit
- 2.996908637328003
- periapsis
- 2.606856335379933
- apoapsis
- 3.386960939276072
- longitude of ascending node
- 120.9334178970166
- argument of periapsis
- 134.4583143122399
- mean anomaly
- 338.8528169706174
- time of periapsis
- 2461111.8162853355
- epoch
- November 21, 2025
Sources (2)
via Wikidata · CC0
~4 min read
Encyclopedic overview
850 Altona (prov. designation: A916 FG or 1916 Σ24) is a large background asteroid, approximately 77 kilometers (48 miles) in diameter, that is located in the outer region of the asteroid belt. It was discovered on 27 March 1916, by Russian astronomer Sergey Belyavsky at the Simeiz Observatory on the Crimean peninsula. The X-type asteroid has a rotation period of 11.2 hours. It was named after the city of Altona near Hamburg, Germany.
Orbit and classification
Excerpted from Wikipedia’s “Q157421” article, available under the CC BY-SA 4.0 licence.