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
- J. Palisa
- Discovery site
- Vienna Obs.
- Discovery date
- 25 August 1909
- Named after
- unknown
- Alternative designations
- A909 QC · 1927 SR, 1940 SJ · A917 KD, 1909 HH
- Minor planet category
- main-belt · ( middle ) , background
- Observation arc
- 106.92 yr (39,054 d)
- Aphelion
- 3.0733 AU
- Perihelion
- 2.3217 AU
- Semi major axis
- 2.6975 AU
- Orbital period sidereal
- 4.43 yr (1,618 d)
- Mean anomaly
- 20.621 °
- Mean motion
- 0° 13 21 / day
- Inclination
- 10.244°
- Longitude of ascending node
- 170.84°
- Argument of perihelion
- 138.97°
- Mean diameter
- 41.40 ± 3.1 km 41.614 ± 0.228 km 49.12 ± 0.60 km
- Synodic rotation period
- 18.87 ± 0.01 h
via Wikipedia infobox
Wikidata facts
- Instance of
- asteroid
- Followed by
- 689 Zita
- Follows
- 687 Tinette
- Parent body
- Sun
- Minor-planet group
- asteroid belt
- Diameter
- 41.614
- Orbital period
- 1619.305599377156
Show 18 more facts
- discoverer or inventor
- Johann Palisa
- site of astronomical discovery
- Vienna Observatory
- provisional designation
- A909 QC
- time of discovery or invention
- 1909-08-25
- albedo
- 0.068
- rotation period
- 18.87
- asteroid spectral type
- C-type asteroid
- absolute magnitude
- 10.98
- orbital eccentricity
- 0.1378323355702989
- semi-major axis of an orbit
- 2.698693691456229
- periapsis
- 2.326726436973985
- apoapsis
- 3.070660945938473
- orbital inclination
- 10.24354044855331
- longitude of ascending node
- 170.8042313921621
- argument of periapsis
- 139.3707257680003
- mean anomaly
- 105.0074688599757
- time of periapsis
- 2460528.168938052
- epoch
- November 21, 2025
Sources (2)
via Wikidata · CC0
~4 min read
Encyclopedic overview
688 Melanie (prov. designation: A909 QC or 1909 HH) is a dark background asteroid from the central regions of the asteroid belt. It was discovered by Austrian astronomer Johann Palisa at the Vienna Observatory on 25 August 1909. The carbonaceous C-type asteroid has a rotation period of 18.9 hours and measures approximately 42 kilometers (26 miles) in diameter. Any reference to the origin of the asteroid's name is unknown.
Orbit and classification
Excerpted from Wikipedia’s “688 Melanie” article, available under the CC BY-SA 4.0 licence.