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
Small body data
(1536) Pielinen
- Orbit class
- Main-belt
- Semi-major axis
- 2.204 AU
- Eccentricity
- 0.196
- Inclination
- 1.536 °
- Absolute magnitude
- 12.810 H
via Minor Planet Center
Key facts
- Discovered by
- Y. Väisälä
- Discovery site
- Turku Observatory
- Discovery date
- 18 September 1939
- Named after
- Pielinen (lake)
- Alternative designations
- 1939 SE · 1929 RZ, 1931 ED · 1934 CW, 1939 TP · 1939 UK, 1952 RW · A903 SF, A916 RA
- Minor planet category
- main-belt · Flora
- Observation arc
- 113.68 yr (41,521 days)
- Aphelion
- 2.6342 AU
- Perihelion
- 1.7736 AU
- Semi major axis
- 2.2039 AU
- Orbital period sidereal
- 3.27 yr (1,195 days)
- Mean anomaly
- 295.85 °
- Mean motion
- 0° 18 4.32 / day
- Inclination
- 1.5344°
- Longitude of ascending node
- 195.69°
- Argument of perihelion
- 170.76°
- Dimensions
- 7.38 ± 1.62 km , 7.82 km (calculated) , 7.934 ± 0.037 km , 7.975 ± 0.109 km
- Synodic rotation period
- 66.1 ± 0.1 h , 66.22 h , 66.34 ± 0.02 h , 67.43 ± 0.06 h
via Wikipedia infobox
Wikidata facts
- Instance of
- asteroid
- Named after
- Pielinen
- Followed by
- 1537 Transylvania
- Follows
- 1535 Päijänne
- Parent body
- Sun
- Minor-planet group
- asteroid belt
- Diameter
- 7.975
- Orbital period
- 1195.299066689146
Show 17 more facts
- discoverer or inventor
- Yrjö Väisälä
- site of astronomical discovery
- Iso-Heikkilä Observatory
- provisional designation
- A916 RA
- time of discovery or invention
- 1939-09-18
- orbital eccentricity
- 0.1955955855878413
- orbital inclination
- 1.535200263620589
- periapsis
- 1.773072718704844
- apoapsis
- 2.635338490725346
- semi-major axis of an orbit
- 2.204205604715095
- mean anomaly
- 119.4191647893861
- longitude of ascending node
- 195.5882141126719
- argument of periapsis
- 170.7767423488217
- absolute magnitude
- 12.84
- albedo
- 0.253
- rotation period
- 66.22
- time of periapsis
- 2460603.995510507
- epoch
- November 21, 2025
Sources (2)
via Wikidata · CC0
~3 min read
Encyclopedic overview
1536 Pielinen (provisional designation 1939 SE) is a stony Florian asteroid from the inner regions of the asteroid belt, approximately 7.8 kilometers in diameter. It was discovered on 18 September 1939, by Finnish astronomer Yrjö Väisälä at Turku Observatory, Southwest Finland. It was later named for Finnish lake Pielinen.
Classification and orbit
Excerpted from Wikipedia’s “1536 Pielinen” article, available under the CC BY-SA 4.0 licence.