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
- 26 January 1938
- Named after
- Frans Sillanpää ( writer )
- Alternative designations
- 1938 BA · 1935 GB, 1952 HQ 3 · 1955 DQ, 1965 EA
- Minor planet category
- main-belt · Flora
- Observation arc
- 78.53 yr (28,683 days)
- Aphelion
- 2.4732 AU
- Perihelion
- 2.0179 AU
- Semi major axis
- 2.2455 AU
- Orbital period sidereal
- 3.37 yr (1,229 days)
- Mean anomaly
- 98.112 °
- Mean motion
- 0° 17 34.44 / day
- Inclination
- 5.2572°
- Longitude of ascending node
- 17.549°
- Argument of perihelion
- 196.25°
- Dimensions
- 7.35 ± 0.29 km , 8.167 ± 0.154 km , 8.19 km (calculated) , 8.763 ± 0.063 km
- Synodic rotation period
- 9.658 55 ± 0.000 05 h , 9.659 ± 0.001 h , 9.6597 ± 0.0172 h , 9.6602 ± 0.0008 h
via Wikipedia infobox
Wikidata facts
- Instance of
- asteroid
- Named after
- Frans Eemil Sillanpää
- Followed by
- 1447 Utra
- Follows
- 1445 Konkolya
- Parent body
- Sun
- Minor-planet group
- asteroid belt
- Diameter
- 8.167
- Orbital period
- 1229.195692135343
- Image
- 001446-asteroid shape model (1446) Sillanpää.png
Show 18 more facts
- discoverer or inventor
- Yrjö Väisälä
- site of astronomical discovery
- Iso-Heikkilä Observatory
- provisional designation
- 1965 EA
- time of discovery or invention
- 1938-01-26
- orbital eccentricity
- 0.100532554636384
- orbital inclination
- 5.252046944768838
- periapsis
- 2.019918520528981
- apoapsis
- 2.471446966773152
- semi-major axis of an orbit
- 2.245682743651066
- mean anomaly
- 315.1779896923129
- longitude of ascending node
- 17.40937472025924
- argument of periapsis
- 196.4405719057934
- absolute magnitude
- 12.76
- Commons category
- 1446 Sillanpää
- albedo
- 0.241
- rotation period
- 9.6602
- time of periapsis
- 2461153.5417277305
- epoch
- November 21, 2025
Sources (3)
via Wikidata · CC0
~3 min read
Encyclopedic overview
1446 Sillanpää, provisional designation 1938 BA, is a stony Florian asteroid from the inner regions of the asteroid belt, approximately 8.2 kilometers in diameter. It was discovered on 26 January 1938, by Finnish astronomer Yrjö Väisälä at Turku Observatory in Southwest Finland. It was later named after writer Frans Eemil Sillanpää.
Orbit and classification
Excerpted from Wikipedia’s “1446 Sillanpää” article, available under the CC BY-SA 4.0 licence.