59 Elpis

Also known as (59) Elpis, Elpis

main-belt asteroid

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: Jean Chacornac
Discovery date: September 12, 1860
Pronunciation: / ˈ ɛ l p ɪ s /
Named after: Elpis
Minor planet category: Main belt
Adjectives: Elpidian / ɛ l ˈ p ɪ d i ə n /
Aphelion: 453.624 million km (3.032 AU)
Perihelion: 358.808 million km (2.398 AU)
Semi major axis: 406.216 million km (2.715 AU )
Orbital period sidereal: 1634.355 d (4.47 a )
Mean anomaly: 246.848°
Inclination: 8.631°
Longitude of ascending node: 170.209°
Argument of perihelion: 210.901°
Dimensions: 164.8 ± 6.0 km
Mass: (3.00 ± 0.50) × 10 kg
Mean density: 1.30 ± 0.26 g/cm
Synodic rotation period: 13.69 h

via Wikipedia infobox

~2 min read

Encyclopedic overview

59 Elpis is a large main belt asteroid that orbits the Sun with a period of 4.47 years. It is a C-type asteroid, meaning that it is very dark and carbonaceous in composition. In the Tholen scheme it has a classification of CP, while Bus and Binzen class it as type B.

Elpis was discovered by Jean Chacornac from Paris, on September 12, 1860. It was Chacornac's sixth and final asteroid discovery.

Excerpted from Wikipedia’s “59 Elpis” article, available under the CC BY-SA 4.0 licence.