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
- Max Wolf
- Discovery site
- Heidelberg
- Discovery date
- 3 August 1918
- Pronunciation
- German: [ joːkastə ] , Classically: p / dʒ oʊ ˈ k æ s t iː /
- Alternative designations
- 1918 EB
- Observation arc
- 97.71 yr (35688 days)
- Aphelion
- 3.4884 AU (521.86 Gm )
- Perihelion
- 2.3242 AU (347.70 Gm)
- Semi major axis
- 2.9063 AU (434.78 Gm)
- Orbital period sidereal
- 4.95 yr (1809.7 d )
- Mean anomaly
- 229.912 °
- Mean motion
- 0° 11 56.148 / day
- Inclination
- 12.467°
- Longitude of ascending node
- 252.430°
- Argument of perihelion
- 127.690°
- Earth moid
- 1.35068 AU (202.059 Gm)
- Jupiter moid
- 2.07017 AU (309.693 Gm)
- Mean radius
- 13.845 ± 0.45 km
via Wikipedia infobox
Wikidata facts
- Instance of
- asteroid
- Followed by
- 900 Rosalinde
- Follows
- 898 Hildegard
- Parent body
- Sun
- Minor-planet group
- asteroid belt
- Diameter
- 31.018
- Orbital period
- 1808.685077313957
Show 18 more facts
- discoverer or inventor
- Max Wolf
- site of astronomical discovery
- Heidelberg-Königstuhl State Observatory
- provisional designation
- A918 PH
- time of discovery or invention
- 1918-08-03
- rotation period
- 6.245
- asteroid spectral type
- X-type asteroid
- albedo
- 0.161
- absolute magnitude
- 10.26
- orbital eccentricity
- 0.2013806726601349
- semi-major axis of an orbit
- 2.905202119746651
- periapsis
- 2.320150562658421
- apoapsis
- 3.490253676834882
- orbital inclination
- 12.47797669008152
- longitude of ascending node
- 252.3556490887116
- argument of periapsis
- 127.1021771954799
- mean anomaly
- 187.0961970966558
- time of periapsis
- 2461869.1903558946
- epoch
- November 21, 2025
Sources (3)
via Wikidata · CC0
~1 min read
Encyclopedic overview
899 Jokaste is a minor planet orbiting the Sun. It was one of five minor planets included in the 1993 study, Transition Comets -- UV Search for OH Emissions in Asteroids, which was research involving amateur astronomers who were permitted to make use of the Hubble Space Telescope. Not to be confused with Iocaste, a moon of Jupiter.
References
Excerpted from Wikipedia’s “899 Jokaste” article, available under the CC BY-SA 4.0 licence.