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
- Taunton, Massachusetts
- Discovery date
- 30 September 1908
- Alternative designations
- 1908 EJ
- Observation arc
- 99.16 yr (36218 d)
- Aphelion
- 2.6327 AU (393.85 Gm )
- Perihelion
- 2.1142 AU (316.28 Gm)
- Semi major axis
- 2.3734 AU (355.06 Gm)
- Orbital period sidereal
- 3.66 yr (1335.6 d )
- Mean anomaly
- 133.453 °
- Mean motion
- 0° 16 10.38 / day
- Inclination
- 8.1694°
- Longitude of ascending node
- 22.515°
- Argument of perihelion
- 44.204°
- Mean radius
- 16.045 ± 0.7 km
- Synodic rotation period
- 6.5837 h (0.27432 d )
- Geometric albedo
- 0.1427 ± 0.014
- Spectral type
- M
via Wikipedia infobox
Wikidata facts
- Diameter
- 32.894
- Orbital period
- 1335.147406491775
Show 15 more facts
- provisional designation
- A908 TG
- time of discovery or invention
- 1908-09-30
- orbital inclination
- 8.171452825662252
- Commons category
- 757 Portlandia
- albedo
- 0.217
- rotation period
- 6.5837
- absolute magnitude
- 10.06
- orbital eccentricity
- 0.1081706185340355
- semi-major axis of an orbit
- 2.372942381669909
- periapsis
- 2.116259736499047
- apoapsis
- 2.62962502684077
- longitude of ascending node
- 22.41707299442378
- argument of periapsis
- 44.35040336597263
- mean anomaly
- 329.9386140593471
- time of periapsis
- 2461111.9899485395
Sources (2)
via Wikidata · CC0
~1 min read
Article
757 Portlandia is a main-belt asteroid 32 km in diameter. It was discovered on 30 September 1908 from Taunton, Massachusetts by the amateur American astronomer Joel E. Metcalf. The asteroid was named for the city of Portland, Maine, where Hastings was a church minister at the time. In November 2015, amateur astronomers captured it with images of comet 67P/Churyumov–Gerasimenko. Portlandia came to opposition in March 2016 at apparent magnitude 13.2.
This body is orbiting the Sun at a distance of 2.37 AU with a period of 3.66 years and an eccentricity of 0.109. The orbital plane is inclined at an angle of 8.2° to the plane of the ecliptic. 757 Portlandia is classified as an X-type asteroid and is a core member of the proposed Athor asteroid family, named after 161 Athor. This asteroid spans a girth of 32.89±0.24 km and is rotating with a period of 6.58 hours. During 2003, the asteroid was observed occulting a star. The resulting chords were used to determine a diameter estimate of 36.7 km.