File:149Medusa_(Lightcurve_Inversion).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
- Henri Joseph Perrotin
- Discovery date
- 21 September 1875
- Pronunciation
- / m ɪ ˈ dj uː s ə /
- Named after
- Medusa
- Alternative designations
- A875 SA; 1905 BA;, 1906 HB
- Minor planet category
- Main belt
- Observation arc
- 124.55 yr (45493 d)
- Aphelion
- 2.32 AU (346.60 Gm )
- Perihelion
- 2.03 AU (304.06 Gm)
- Semi major axis
- 2.17 AU (325.33 Gm)
- Orbital period sidereal
- 3.21 yr (1,171.4 d)
- Average orbital speed
- 20.18 km/s
- Mean anomaly
- 280.686 °
- Mean motion
- 0° 18 26.374 / day
- Inclination
- 0.93927°
- Longitude of ascending node
- 159.615°
- Argument of perihelion
- 250.609°
- Earth moid
- 1.04 AU (155.77 Gm)
via Wikipedia infobox
~2 min read
Encyclopedic overview
149 Medusa is a bright-coloured, stony main-belt asteroid that was discovered by French astronomer J. Perrotin on September 21, 1875, and named after the Gorgon Medusa, a snake-haired monster in Greek mythology. It is orbiting the Sun at a distance of 2.17 AU with a period of 3.21 years and an eccentricity of 0.065. The orbital plane is tilted slightly at an angle of 0.94° to the plane of the ecliptic.
When it was discovered, Medusa was by far the smallest asteroid found (although this was not known at that time). Since then, many thousands of smaller asteroids have been found. It was also the closest asteroid to the Sun discovered up to that point, beating the long-held record of 8 Flora. It remained the closest asteroid to the Sun until 433 Eros and 434 Hungaria were found in 1898, leading to the discovery of two new families of asteroids inward from the 4:1 Kirkwood gap which forms the boundary of the main belt.
Excerpted from Wikipedia’s “149 Medusa” article, available under the CC BY-SA 4.0 licence.