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
- M. F. Wolf
- Discovery site
- Heidelberg Obs.
- Discovery date
- 30 October 1918
- Named after
- Fairy tale character "Ilsebill" , ( The Fisherman and his Wife )
- Alternative designations
- A918 UD · 1935 JG, 1950 RP · 1950 SE, 1950 TN · 1972 MA, 1918 EQ
- Minor planet category
- main-belt · ( middle ) , background
- Observation arc
- 101.19 yr (36,960 d)
- Aphelion
- 3.0033 AU
- Perihelion
- 2.5408 AU
- Semi major axis
- 2.7721 AU
- Orbital period sidereal
- 4.62 yr (1,686 d)
- Mean anomaly
- 14.861 °
- Mean motion
- 0° 12 48.96 / day
- Inclination
- 8.1657°
- Longitude of ascending node
- 229.83°
- Argument of perihelion
- 156.02°
- Mean diameter
- 27.65 ± 1.7 km 33.41 ± 0.49 km 33.500 ± 0.071 km
- Synodic rotation period
- 5.0325 ± 0.0011 h
via Wikipedia infobox
Wikidata facts
- Instance of
- asteroid
- Followed by
- 920 Rogeria
- Follows
- 918 Itha
- Parent body
- Sun
- Minor-planet group
- asteroid belt
- Diameter
- 33.5
- Orbital period
- 1687.379779150416
Show 18 more facts
- discoverer or inventor
- Max Wolf
- site of astronomical discovery
- Heidelberg-Königstuhl State Observatory
- provisional designation
- A918 UD
- time of discovery or invention
- 1918-10-30
- albedo
- 0.047
- rotation period
- 5.0325
- asteroid spectral type
- C-type asteroid
- absolute magnitude
- 11.64
- orbital eccentricity
- 0.08565331155757103
- semi-major axis of an orbit
- 2.773807229125176
- periapsis
- 2.536221454328275
- apoapsis
- 3.011393003922078
- orbital inclination
- 8.159735825752545
- longitude of ascending node
- 229.7613726659853
- argument of periapsis
- 156.7008302206962
- mean anomaly
- 81.15922209940938
- time of periapsis
- 2460620.093249272
- epoch
- November 21, 2025
Sources (2)
via Wikidata · CC0
~4 min read
Encyclopedic overview
919 Ilsebill (prov. designation: A918 UD or 1918 EQ) is a dark background asteroid from the central region of the asteroid belt. It was discovered on 30 October 1918, by astronomer Max Wolf at the Heidelberg-Königstuhl State Observatory in southwest Germany. The carbonaceous C-type asteroid has a short rotation period of 5.0 hours and measures approximately 33 kilometers (21 miles) in diameter. It was named after "Ilsebill", a character in the fairy tale The Fisherman and his Wife by the Brothers Grimm.
Orbit and classification
Excerpted from Wikipedia’s “919 Ilsebill” article, available under the CC BY-SA 4.0 licence.