Image by mina6120 on Pixabay · Pixabay License
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
- E. L. Johnson
- Discovery site
- Union Obs.
- Discovery date
- 7 September 1947
- Named after
- Union Observatory , (aka Johannesburg Obs.)
- Alternative designations
- 1947 RG · 1929 DB, 1937 QF · 1939 CD 1 , 1944 DG · 1949 EE, 1952 QA 1 · 1952 SD
- Minor planet category
- main-belt · ( outer )
- Observation arc
- 78.37 yr (28,624 days)
- Aphelion
- 3.8332 AU
- Perihelion
- 2.0231 AU
- Semi major axis
- 2.9281 AU
- Orbital period sidereal
- 5.01 yr (1,830 days)
- Mean anomaly
- 304.39 °
- Mean motion
- 0° 11 48.12 / day
- Inclination
- 26.187°
- Longitude of ascending node
- 150.10°
- Argument of perihelion
- 264.54°
- Dimensions
- 49.01 ± 18.07 km , 50.42 ± 1.6 km , 50.68 ± 0.88 km , 55.271 ± 0.243 km , 55.42 ± 18.20 km , 56.014 ± 0.292 km
- Synodic rotation period
- 9.38 h , 24 h (fragmentary)
via Wikipedia infobox
Wikidata facts
- Instance of
- asteroid
- Named after
- Union Observatory
- Followed by
- 1586 Thiele
- Follows
- 1584 Fuji
- Parent body
- Sun
- Minor-planet group
- asteroid belt
- Diameter
- 55.271
- Orbital period
- 1831.957505063468
- Image
- Орбита астероида 1585 (наклон).png
Show 18 more facts
- discoverer or inventor
- Ernest Leonard Johnson
- site of astronomical discovery
- Union Observatory
- provisional designation
- 1952 SD
- time of discovery or invention
- 1947-09-07
- orbital eccentricity
- 0.3083623390202739
- orbital inclination
- 26.17056984563076
- periapsis
- 2.026546682545816
- apoapsis
- 3.833593089701838
- semi-major axis of an orbit
- 2.930069886123827
- mean anomaly
- 174.8800443946219
- longitude of ascending node
- 150.0593681177941
- argument of periapsis
- 264.2354573425786
- absolute magnitude
- 10.31
- Commons category
- 1585 Union
- albedo
- 0.031
- rotation period
- 12.798
- time of periapsis
- 2460110.575528293
- epoch
- November 21, 2025
Sources (3)
via Wikidata · CC0
~3 min read
Encyclopedic overview
1585 Union, provisional designation 1947 RG, is a dark background asteroid from the outer regions of the asteroid belt, approximately 52 kilometers in diameter. It was discovered on 7 September 1947, by South African astronomer Ernest Johnson at the Union Observatory in Johannesburg, South Africa. The asteroid was named after the discovering observatory.
Orbit and classification
Excerpted from Wikipedia’s “1585 Union” article, available under the CC BY-SA 4.0 licence.