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
- 11 December 1909
- Pronunciation
- / ˈ l iː h aɪ /
- Alternative designations
- 1909 JG
- Observation arc
- 101.40 yr (37038 d)
- Aphelion
- 3.3787 AU (505.45 Gm )
- Perihelion
- 2.6443 AU (395.58 Gm)
- Semi major axis
- 3.0115 AU (450.51 Gm)
- Orbital period sidereal
- 5.23 yr (1908.9 d )
- Mean anomaly
- 189.349 °
- Mean motion
- 0° 11 18.924 / day
- Inclination
- 13.010°
- Longitude of ascending node
- 87.997°
- Argument of perihelion
- 304.466°
- Mean radius
- 43.84 ± 0.85 km
- Synodic rotation period
- 12.891 h (0.5371 d )
- Geometric albedo
- 0.0438 ± 0.002
via Wikipedia infobox
Wikidata facts
- Instance of
- asteroid
- Followed by
- 692 Hippodamia
- Follows
- 690 Wratislavia
- Parent body
- Sun
- Minor-planet group
- asteroid belt
- Diameter
- 79.451
- Orbital period
- 1906.184929560064
Show 20 more facts
- discoverer or inventor
- Joel Hastings Metcalf
- provisional designation
- A909 XB
- time of discovery or invention
- 1909-12-11
- site of astronomical discovery
- Taunton
- title
- (691) Lehigh
- page(s)
- 67-67
- albedo
- 0.053
- rotation period
- 12.891
- asteroid spectral type
- C-type asteroid
- absolute magnitude
- 9.31
- orbital eccentricity
- 0.1255701732855624
- semi-major axis of an orbit
- 3.00869203647713
- periapsis
- 2.630890056093805
- apoapsis
- 3.386494016860454
- orbital inclination
- 13.02285057811589
- longitude of ascending node
- 87.92435825092305
- argument of periapsis
- 303.3222724468538
- mean anomaly
- 111.9650056058039
- time of periapsis
- 2460407.6499824338
- epoch
- November 21, 2025
Sources (2)
via Wikidata · CC0
~1 min read
Encyclopedic overview
691 Lehigh is an asteroid orbiting the Sun in the asteroid belt, discovered in 1909. It is named after Lehigh University, where its orbit was calculated in the Masters Thesis of Joseph B. Reynolds, following the observations of amateur astronomer Joel Metcalf. The asteroid is a CD:-type asteroid, suggesting its surface is largely carbonaceous, with many primitive molecules similar to those of comets. Due to this, it has a cometlike surface albedo of just 0.05, similar to fresh asphalt, meaning that it reflects only 5% of light that hits it. Lehigh is not known to be a member of any collisional asteroid family.
References
Excerpted from Wikipedia’s “691 Lehigh” article, available under the CC BY-SA 4.0 licence.