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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
- Y. Väisälä
- Discovery site
- Turku Obs.
- Discovery date
- 12 September 1936
- Named after
- Jean Sibelius , (Finnish composer)
- Alternative designations
- 1936 RE · 1951 CO, 1953 VK 3 · 1963 ST
- Minor planet category
- main-belt · Flora
- Observation arc
- 66.40 yr (24,254 days)
- Aphelion
- 2.5817 AU
- Perihelion
- 1.9215 AU
- Semi major axis
- 2.2516 AU
- Orbital period sidereal
- 3.38 yr (1,234 days)
- Mean anomaly
- 312.34 °
- Mean motion
- 0° 17 30.12 / day
- Inclination
- 7.0301°
- Longitude of ascending node
- 312.08°
- Argument of perihelion
- 95.795°
- Dimensions
- 6.21 ± 0.35 km , 6.810 ± 0.098 km , 7.175 ± 0.089 km , 7.20 km (taken) , 7.204 km , 9.26 ± 1.95 km , 12.18 ± 1.1 km
- Synodic rotation period
- 6.051 ± 0.001 h
via Wikipedia infobox
Wikidata facts
- Instance of
- asteroid
- Named after
- Jean Sibelius
- Followed by
- (1406) Komppa
- Follows
- 1404 Ajax
- Parent body
- Sun
- Minor-planet group
- asteroid belt
- Diameter
- 6.81
- Orbital period
- 1233.803421693097
Show 17 more facts
- discoverer or inventor
- Yrjö Väisälä
- site of astronomical discovery
- Iso-Heikkilä Observatory
- provisional designation
- 1963 ST
- time of discovery or invention
- 1936-09-12
- orbital eccentricity
- 0.1460541426043983
- orbital inclination
- 7.035231269890226
- periapsis
- 1.922480890921958
- apoapsis
- 2.580101736002933
- semi-major axis of an orbit
- 2.251291313462445
- mean anomaly
- 107.2921300427676
- longitude of ascending node
- 312.0024552234703
- argument of periapsis
- 95.8915520054868
- absolute magnitude
- 12.8
- albedo
- 0.388
- rotation period
- 6.051
- time of periapsis
- 2460632.785007868
- epoch
- November 21, 2025
Sources (3)
via Wikidata · CC0
~3 min read
Encyclopedic overview
1405 Sibelius (provisional designation 1936 RE) is a stony Florian asteroid from the inner regions of the asteroid belt, approximately 8 kilometers in diameter. It was discovered on 12 September 1936, by Finnish astronomer Yrjö Väisälä at Turku Observatory in Southwest Finland. The asteroid was named after composer Jean Sibelius.
Orbit and classification
Excerpted from Wikipedia’s “1405 Sibelius” article, available under the CC BY-SA 4.0 licence.