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
- Y. Väisälä
- Discovery site
- Turku Observatory
- Discovery date
- 24 February 1938
- Named after
- Friedrich Bessel , (German astronomer)
- Alternative designations
- 1938 DE 1 · 1933 FJ 1 , 1948 EH · 1951 UF
- Minor planet category
- main-belt · Eos
- Observation arc
- 84.11 yr (30,722 days)
- Aphelion
- 3.3068 AU
- Perihelion
- 2.7174 AU
- Semi major axis
- 3.0121 AU
- Orbital period sidereal
- 5.23 yr (1,909 days)
- Mean anomaly
- 185.26 °
- Mean motion
- 0° 11 18.6 / day
- Inclination
- 9.8367°
- Longitude of ascending node
- 9.9835°
- Argument of perihelion
- 39.607°
- Dimensions
- 16.63 ± 0.84 km , 18.33 km (derived) , 18.514 ± 0.066 km , 18.817 ± 0.101 km
- Synodic rotation period
- 8.963 18 ± 0.000 02 h , 8.996 ± 0.006 h
via Wikipedia infobox
~3 min read
Encyclopedic overview
1552 Bessel (provisional designation 1938 DE1) is a stony Eoan asteroid from the outer regions of the asteroid belt, approximately 18 kilometers in diameter. It was discovered on 24 February 1938, by Finnish astronomer Yrjö Väisälä at Turku Observatory in Southwest Finland, and named after German astronomer Friedrich Bessel.
Orbit and classification
Excerpted from Wikipedia’s “Q140745” article, available under the CC BY-SA 4.0 licence.