File:201_Penelope.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
- Johann Palisa
- Discovery date
- 7 August 1879
- Pronunciation
- / p ɪ ˈ n ɛ l ə p iː /
- Named after
- Penelópē
- Alternative designations
- A879 PA; 1869 GA
- Minor planet category
- Main belt
- Adjectives
- Penelopean / p ɪ ˈ n ɛ l oʊ ˈ p iː ə n /
- Observation arc
- 142.58 yr (52,077 d)
- Aphelion
- 3.160 AU (472.710 Gm )
- Perihelion
- 2.199 AU (329.009 Gm)
- Semi major axis
- 2.680 AU (400.859 Gm)
- Orbital period sidereal
- 4.39 yr (1,602.14 d)
- Average orbital speed
- 18.19 km/s
- Mean anomaly
- 169.01173°
- Mean motion
- 0° 13 28.917 / day
- Inclination
- 5.75625°
- Longitude of ascending node
- 156.91554°
- Argument of perihelion
- 180.90559°
via Wikipedia infobox
~1 min read
Encyclopedic overview
201 Penelope is a large main belt asteroid that was discovered by Austrian astronomer Johann Palisa on August 7, 1879, in Pola. The asteroid is named after Penelope, the wife of Odysseus in Homer's The Odyssey. It is orbiting the Sun at a distance of 2.68 AU with an eccentricity (ovalness) of 0.18 and a period of 4.381 years. The orbital plane is tilted at an angle of 5.8° to the plane of the ecliptic.
Based upon the spectra of this object, it is classified as a M-type asteroid, indicating it may be metallic in composition. It may be the remnant of the core of a larger, differentiated asteroid. Near infrared absorption features indicate the presence of variable amounts of low-iron, low-calcium orthopyroxenes on the surface. Trace amounts of water is detected with a mass fraction of about 0.13–0.15 wt%. It has an estimated size of around 88 km. With a rotation period of 3.74 hours, it is the fastest rotating asteroid larger than 50 km in diameter.
Excerpted from Wikipedia’s “201 Penelope” article, available under the CC BY-SA 4.0 licence.