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 date
- 16 February 1912
- Pronunciation
- / l iː ə ˈ n aɪ s ɪ s /
- Alternative designations
- 1912 NU; A907 UE;, 1941 WR; 1968 UT
- Minor planet category
- Main belt ( Flora family )
- Observation arc
- 103.98 yr (37979 d)
- Aphelion
- 2.4509 AU (366.65 Gm )
- Perihelion
- 2.0561 AU (307.59 Gm)
- Semi major axis
- 2.2535 AU (337.12 Gm)
- Orbital period sidereal
- 3.38 yr (1235.6 d )
- Average orbital speed
- 19.80 km/s
- Mean anomaly
- 317.487 °
- Mean motion
- 0° 17 28.86 / day
- Inclination
- 4.2564°
- Longitude of ascending node
- 82.661°
- Argument of perihelion
- 55.396°
- Synodic rotation period
- 5.5783 h (0.23243 d )
- Spectral type
- A or Ld
via Wikipedia infobox
Wikidata facts
- Instance of
- asteroid
- Named after
- Isis
- Followed by
- Q156779
- Follows
- Q156773
- Parent body
- Sun
- Minor-planet group
- asteroid belt
- Diameter
- 5.887
- Orbital period
- 1235.695380876698
Show 18 more facts
- discoverer or inventor
- Johann Palisa
- site of astronomical discovery
- Vienna Observatory
- provisional designation
- A912 DB
- time of discovery or invention
- 1912-02-16
- orbital inclination
- 4.256518078841229
- Commons category
- 728 Leonisis
- albedo
- 0.16
- rotation period
- 5.5783
- absolute magnitude
- 12.87
- orbital eccentricity
- 0.08737375537046661
- semi-major axis of an orbit
- 2.253592200496105
- periapsis
- 2.056687386865167
- apoapsis
- 2.450497014127043
- longitude of ascending node
- 82.5546004970259
- argument of periapsis
- 55.97837082754015
- mean anomaly
- 227.2824996771541
- time of periapsis
- 2461456.0511169736
- epoch
- November 21, 2025
Sources (2)
via Wikidata · CC0
~1 min read
Encyclopedic overview
728 Leonisis is an asteroid of the Flora family, discovered by Austrian astronomer Johann Palisa on 16 February 1912 from Vienna.
There is some uncertainty as to its spectral class. It has been previously placed in the rare A and Ld classes. These are generally "stony" spectra, but with significant deviations from the usual S-type. The unusual spectrum brings Leonisis' membership in the Flora family into doubt.
Excerpted from Wikipedia’s “728 Leonisis” article, available under the CC BY-SA 4.0 licence.