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 Observatory
- Discovery date
- 10 January 1904
- Pronunciation
- German: [ ˈhɛlɡaː ]
- Alternative designations
- 1904 NC
- Observation arc
- 114.65 yr (41876 d)
- Aphelion
- 3.9372 AU (589.00 Gm )
- Perihelion
- 3.3284 AU (497.92 Gm)
- Semi major axis
- 3.6328 AU (543.46 Gm)
- Orbital period sidereal
- 6.92 yr (2529.1 d )
- Mean anomaly
- 200.06 °
- Mean motion
- 0° 8 32.424 / day
- Inclination
- 4.4174°
- Longitude of ascending node
- 116.683°
- Argument of perihelion
- 246.503°
- Mean radius
- 50.61 ± 1.75 km
- Synodic rotation period
- 8.129 h (0.3387 d )
- Geometric albedo
- 0.0388 ± 0.003
via Wikipedia infobox
Wikidata facts
- Instance of
- asteroid
- Followed by
- Q155140
- Follows
- 521 Brixia
- Parent body
- Sun
- Diameter
- 101.22
- Orbital period
- 2523.123765128066
Show 18 more facts
- discoverer or inventor
- Max Wolf
- site of astronomical discovery
- Heidelberg-Königstuhl State Observatory
- provisional designation
- A902 WB
- time of discovery or invention
- 1904-01-10
- orbital inclination
- 4.419968531609906
- albedo
- 0.0388
- rotation period
- 8.129
- asteroid spectral type
- X-type asteroid
- absolute magnitude
- 9.02
- orbital eccentricity
- 0.08601973496013122
- semi-major axis of an orbit
- 3.627104639712733
- periapsis
- 3.315102059931981
- apoapsis
- 3.939107219493484
- longitude of ascending node
- 116.5338464966673
- argument of periapsis
- 249.3997799375774
- mean anomaly
- 322.4472648943717
- time of periapsis
- 2461263.6949955295
- epoch
- November 21, 2025
Sources (2)
via Wikidata · CC0
~1 min read
Encyclopedic overview
522 Helga, provisional designation 1904 NC is a large main belt asteroid (minor planet). It was discovered in 1904 by Max Wolf in Heidelberg. Helga is notable for being the first such object to be shown to be in a stable but chaotic orbit in a 7:12 resonance with Jupiter, its Lyapunov time being relatively short, at 6,900 yr. Despite this, its orbit appears to be stable, as the eccentricity and precession rates are such that it avoids close encounters with Jupiter. It forms part of the Cybele asteroid group.
522 Helga was "named by Lt. Th. Lassen, orbit computer" according to Paul Herget's The Names of the Minor Planets (note that computer does not refer to a personal computer, i.e. a machine, but rather to a person actually doing the necessary calculations).
Excerpted from Wikipedia’s “Q155129” article, available under the CC BY-SA 4.0 licence.