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EntityQ155454· pop 39· linked from 8 articles

Also known as (551) Ortrud, Ortrud, (551) 1904 PM

main-belt asteroid

Picture of the Day · NASA

Pathfinder on Mars

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
16 November 1904
Pronunciation
German: [ ˈɔʁtʁʊt ]
Alternative designations
1904 PM
Observation arc
111.06 yr (40565 d)
Aphelion
3.3325 AU (498.53 Gm )
Perihelion
2.6019 AU (389.24 Gm)
Semi major axis
2.9672 AU (443.89 Gm)
Orbital period sidereal
5.11 yr (1866.9 d )
Mean anomaly
306.688 °
Mean motion
0° 11 34.188 / day
Inclination
0.39727°
Longitude of ascending node
6.0272°
Argument of perihelion
68.010°
Mean radius
39.23 ± 2.05 km
Synodic rotation period
13.05 h (0.544 d )
Geometric albedo
0.0426 ± 0.005

via Wikipedia infobox

Wikidata facts

Instance of
asteroid
Followed by
Q155464
Follows
550 Senta
Parent body
Sun
Minor-planet group
asteroid belt
Diameter
81.113
Orbital period
1868.54011117062
Show 18 more facts
discoverer or inventor
Max Wolf
site of astronomical discovery
Heidelberg-Königstuhl State Observatory
provisional designation
A906 EA
time of discovery or invention
1904-11-16
orbital inclination
0.3941379170362859
albedo
0.04
rotation period
17.416
asteroid spectral type
C-type asteroid
absolute magnitude
9.8
orbital eccentricity
0.1187915100669684
semi-major axis of an orbit
2.968948508135363
periapsis
2.61626263154289
apoapsis
3.321634384727837
longitude of ascending node
5.66182062865937
argument of periapsis
71.04585799610162
mean anomaly
238.8777299690763
time of periapsis
2461629.171721969
Sources (2)

via Wikidata · CC0

~1 min read

Encyclopedic overview

551 Ortrud is a minor planet orbiting the Sun. It is located in the Main Belt. In light of the practice of the discover c. 1904 to name his asteroids after female characters in opera, it is likely that Ortrud is named after a character in Richard Wagner's opera Lohengrin.

References

Excerpted from Wikipedia’s “Q155454” article, available under the CC BY-SA 4.0 licence.