File:000120-asteroid_shape_model_(120)_Lachesis.png · Wikimedia Commons · See Wikimedia Commons
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
- Alphonse Borrelly
- Discovery date
- 10 April 1872
- Pronunciation
- / ˈ l æ k ɪ s ɪ s / LAK -iss-iss
- Named after
- Lachesis
- Alternative designations
- A872 GB; 1910 CF;, 1918 UB
- Minor planet category
- Main belt
- Adjectives
- Lachesian ( / l æ ˈ k iː ʃ ( i ) ə n , l ə ˈ k iː ʒ ə n / la- KEE -sh(ee-)ən, lə- KEE -zhən )
- Observation arc
- 143.70 yr (52485 d)
- Aphelion
- 3.2814 AU (490.89 Gm )
- Perihelion
- 2.95390 AU (441.897 Gm)
- Semi major axis
- 3.11767 AU (466.397 Gm)
- Orbital period sidereal
- 5.50 yr (2010.7 d )
- Average orbital speed
- 16.86 km/s
- Mean anomaly
- 56.2095 °
- Mean motion
- 0° 10 44.558 / day
- Inclination
- 6.9643°
- Longitude of ascending node
- 341.193°
- Argument of perihelion
- 232.822°
via Wikipedia infobox
~1 min read
Encyclopedic overview
120 Lachesis is a large main-belt asteroid. It was discovered by French astronomer Alphonse Borrelly on April 10, 1872, and independently by German-American astronomer Christian Heinrich Friedrich Peters on April 11, 1872, then named after Lachesis, one of the Moirai, or Fates, in Greek mythology. A Lachesean occultation of a star occurred in 1999 and was confirmed visually by five observers and once photoelectrically, with the chords yielding an estimated elliptical cross-section of 184 × 144 km.
This body is orbiting the Sun with a period of 5.50 years and an eccentricity (ovalness) of 0.05. The orbital plane is inclined by 7° to the plane of the ecliptic. Photometric observations of this asteroid were made in early 2009 at the Organ Mesa Observatory in Las Cruces, New Mexico. The resulting light curve shows a synodic rotation period of 46.551 ± 0.002 hours with a brightness variation of 0.14 ± 0.02 in magnitude. It is a very slow rotator with the longest rotation period of an asteroid more than 150 km in diameter. As a primitive C-type asteroid it is probably composed of carbonaceous material.
Excerpted from Wikipedia’s “Q136933” article, available under the CC BY-SA 4.0 licence.