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
- Joel Hastings Metcalf
- Discovery site
- Winchester, Massachusetts
- Discovery date
- 7 December 1912
- Alternative designations
- 1912 QB
- Observation arc
- 100.96 yr (36874 d)
- Aphelion
- 3.2248 AU (482.42 Gm )
- Perihelion
- 1.9562 AU (292.64 Gm)
- Semi major axis
- 2.5905 AU (387.53 Gm)
- Orbital period sidereal
- 4.17 yr (1,522.9 d)
- Mean anomaly
- 24.8306 °
- Mean motion
- 0° 14 11.004 / day
- Inclination
- 12.368°
- Longitude of ascending node
- 184.672°
- Argument of perihelion
- 134.348°
- Mean radius
- 22.035 ± 0.7 km
- Synodic rotation period
- 7.0259 h (0.29275 d )
- Geometric albedo
- 0.2723 ± 0.018
- Spectral type
- S
via Wikipedia infobox
Wikidata facts
- Diameter
- 47.804
- Orbital period
- 1524.779546653539
Show 14 more facts
- provisional designation
- A912 XC
- time of discovery or invention
- 1912-12-07
- orbital inclination
- 12.36333989102641
- albedo
- 0.231
- rotation period
- 7.0259
- absolute magnitude
- 8.94
- orbital eccentricity
- 0.2440162811218136
- semi-major axis of an orbit
- 2.592621315064691
- periapsis
- 1.959979503405459
- apoapsis
- 3.225263126723922
- longitude of ascending node
- 184.5613363553546
- argument of periapsis
- 134.5140518325796
- mean anomaly
- 108.469360483321
- time of periapsis
- 2460541.078160268
Sources (2)
via Wikidata · CC0
~1 min read
Article
737 Arequipa is a minor planet orbiting the Sun. It was discovered by American astronomer Joel Hastings Metcalf on 7 December 1912 from Winchester, Massachusetts. This stony S-type asteroid was named after the Peruvian city of Arequipa, where Harvard's Boyden Observatory was located prior to 1927. It is orbiting at a distance of 2.59 AU from the Sun, with an orbital eccentricity (ovalness) of 0.245 and a period of 4.17 yr. The orbital plane is inclined at an angle of 12.4° to the ecliptic.
The rotation period of this asteroid has proven to be a challenge to determine, most likely because it has a complex shape and a rotation axis with a low inclination. However, during the 2015 apparition, photometric measurements of the asteroid were taken from close to the equatorial perspective. The resulting light curve displayed a rotation period of 7.0259±0.0003 h.