Image by PeterKraayvanger 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
- C. Shoemaker , E. M. Shoemaker
- Discovery date
- 4 March 1986
- Named after
- Amun
- Alternative designations
- 1986 EB
- Minor planet category
- Aten , Venus-crosser asteroid
- Observation arc
- 10923 days (29.91 yr)
- Aphelion
- 1.24677 AU (186.514 Gm )
- Perihelion
- 0.700578 AU (104.8050 Gm)
- Semi major axis
- 0.973675 AU (145.6597 Gm)
- Orbital period sidereal
- 0.961 yr (350.9 d)
- Mean anomaly
- 184.781°
- Mean motion
- 1.02585°/day
- Inclination
- 23.3626°
- Longitude of ascending node
- 358.627°
- Argument of perihelion
- 359.392°
- Earth moid
- 0.250204 AU (37.4300 Gm)
- Mean diameter
- 3.341 km
- Mass
- ~ 1.6 × 10 kg
via Wikipedia infobox
Wikidata facts
- Instance of
- near-Earth object
- Named after
- Amun
- Followed by
- 3555 Miyasaka
- Follows
- 3553 Mera
- Parent body
- Sun
- Minor-planet group
- asteroid belt
- Diameter
- 3.341
- Mass
- 16
- Orbital period
- 351.0945808281836
- Image
- Amun Sept 9 2012.PNG
Show 18 more facts
- discoverer or inventor
- Eugene Merle Shoemaker
- site of astronomical discovery
- Palomar Observatory
- provisional designation
- 1986 EB
- time of discovery or invention
- 1986-03-04
- orbital inclination
- 23.3563682850061
- orbital eccentricity
- 0.2805906629144661
- albedo
- 0.074
- absolute magnitude
- 15.91
- periapsis
- 0.7006909952967992
- apoapsis
- 1.247270920614478
- semi-major axis of an orbit
- 0.9739809579556387
- mean anomaly
- 276.7141507266576
- longitude of ascending node
- 358.5977964295915
- argument of periapsis
- 359.4140837506822
- Commons category
- 3554 Amun
- rotation period
- 2.53001
- time of periapsis
- 2461081.7255842765
- epoch
- November 21, 2025
Sources (2)
via Wikidata · CC0
~2 min read
Encyclopedic overview
3554 Amun is an Aten asteroid, meaning it crosses Earth's orbit, and a Venus-crosser. It was discovered on 4 March 1986 by Carolyn and Eugene Shoemaker at Mount Palomar Observatory, and named for the ancient Egyptian deity Amun. Amun was the fifth Aten asteroid to be numbered.
Photometric observations of 3554 Amun during 2017–2018 were combined to determine a rotation period of 2.53029±0.00002 hours. It has been classified as an M-type asteroid in the Tholen taxonomy, X-type in the Bus taxonomy, and C-, X-, and D-type in the Bus-DeMeo taxonomy. The featureless optical spectrum has a similar slope to the Tagish Lake meteorite, although 3554 Amun is not considered the source. The infrared spectrum of 3554 Amun was found to match a D-type asteroid taxonomy. The estimated diameter is 3.341 kilometers, making it one of the smallest known asteroids to have an M-type classification.
Excerpted from Wikipedia’s “3554 Amun” article, available under the CC BY-SA 4.0 licence.