File:000221-asteroid_shape_model_(221)_Eos.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
- 18 January 1882
- Pronunciation
- / ˈ iː ɒ s /
- Named after
- Eos
- Alternative designations
- A882 BA
- Minor planet category
- Main belt ( Eos )
- Adjectives
- Eoan / iː ˈ oʊ . ən /
- Observation arc
- 130.21 yr (47561 d)
- Aphelion
- 3.3249 AU (497.40 Gm )
- Perihelion
- 2.69594 AU (403.307 Gm)
- Semi major axis
- 3.01044 AU (450.355 Gm)
- Orbital period sidereal
- 5.22 yr (1907.8 d )
- Average orbital speed
- 17.16 km/s
- Mean anomaly
- 66.5202 °
- Mean motion
- 0° 11 19.284 / day
- Inclination
- 10.880°
- Longitude of ascending node
- 141.845°
- Argument of perihelion
- 193.56°
via Wikipedia infobox
Wikidata facts
- Diameter
- 95.469
- Orbital period
- 1909.822274076149
Show 15 more facts
- time of discovery or invention
- 1882-01-18
- orbital inclination
- 10.89025188116619
- albedo
- 0.166
- Commons category
- 221 Eos
- provisional designation
- A882 BA
- rotation period
- 10.443
- absolute magnitude
- 7.73
- orbital eccentricity
- 0.1010595253952547
- semi-major axis of an orbit
- 3.012518238174151
- periapsis
- 2.708074574779722
- apoapsis
- 3.316961901568579
- longitude of ascending node
- 141.7101615518745
- argument of periapsis
- 192.4815502102716
- mean anomaly
- 348.9514797329227
- time of periapsis
- 2461059.113083616
Sources (2)
via Wikidata · CC0
~1 min read
Article
221 Eos is a large main-belt asteroid that was discovered by Austrian astronomer Johann Palisa on January 18, 1882, in Vienna. In 1884, it was named after Eos, the Greek goddess of the dawn, to honour the opening of a new observatory that was hoped to bring about a new dawn for Viennese astronomy.
The asteroid is orbiting the Sun with a semimajor axis of 3.01 AU, a period of 5.22 years, and an eccentricity of 0.1. The orbital plane is inclined by 10.9° to the plane of the ecliptic. It has a mean cross-section of 104 km, and is spinning with a rotation period of 10.4 hours. Based upon its spectral characteristics, this object is classified as a K-type asteroid. The orbital properties show it to be a member of the extensive Eos asteroid family, which is named after it. The spectral properties of the asteroid suggest it may have come from a partially differentiated parent body.