Image by SteveRaubenstine on Pixabay · Pixabay License
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
- K. Reinmuth
- Discovery site
- Heidelberg Obs.
- Discovery date
- 19 March 1919
- Pronunciation
- / æ ɡ ə ˈ m ɛ m n ɒ n /
- Named after
- Agamemnon , (Greek mythology)
- Alternative designations
- 1919 FD · 1937 QD
- Minor planet category
- Jupiter trojan , Greek · background
- Adjectives
- Agamemnonian / ˌ æ ɡ ə m ɛ m ˈ n oʊ n i ə n /
- Observation arc
- 97.93 yr (35,770 d)
- Aphelion
- 5.6232 AU
- Perihelion
- 4.9300 AU
- Semi major axis
- 5.2766 AU
- Orbital period sidereal
- 12.12 yr (4,427 d)
- Mean anomaly
- 236.05 °
- Mean motion
- 0° 4 52.68 / day
- Inclination
- 21.763°
- Longitude of ascending node
- 338.01°
- Argument of perihelion
- 80.874°
via Wikipedia infobox
Wikidata facts
- Instance of
- asteroid
- Named after
- Agamemnon
- Followed by
- 912 Maritima
- Follows
- 910 Anneliese
- Parent body
- Sun
- Diameter
- 131.038
- Orbital period
- 4439.540973609838
- Image
- 911 Agamemnon.png
Show 19 more facts
- discoverer or inventor
- Karl Wilhelm Reinmuth
- site of astronomical discovery
- Heidelberg-Königstuhl State Observatory
- provisional designation
- A919 FB
- time of discovery or invention
- 1919-03-19
- orbital inclination
- 21.7545417646721
- albedo
- 0.072
- rotation period
- 6.592
- Commons category
- 911 Agamemnon
- asteroid spectral type
- D-type asteroid
- absolute magnitude
- 7.86
- orbital eccentricity
- 0.06694706805536868
- semi-major axis of an orbit
- 5.286396832953319
- periapsis
- 4.932488064409908
- apoapsis
- 5.64030560149673
- longitude of ascending node
- 338.0198074427142
- argument of periapsis
- 82.41585435651268
- mean anomaly
- 102.2773004614204
- time of periapsis
- 2459739.2103720317
- epoch
- November 21, 2025
via Wikidata · CC0
~4 min read
Encyclopedic overview
911 Agamemnon, provisional designation 1919 FD, is a Jupiter trojan and a suspected binary asteroid from the Greek camp, approximately 168 kilometers (100 miles) in diameter. It was discovered on 19 March 1919, by German astronomer Karl Reinmuth at the Heidelberg Observatory in southwest Germany. The dark D-type asteroid is likely the second-largest Jupiter trojans and has a rotation period of 6.6 hours. It is named after the Greek King Agamemnon, a main character of the Iliad.
Orbit and classification
Excerpted from Wikipedia’s “911 Agamemnon” article, available under the CC BY-SA 4.0 licence.