File:269_Justitia_occultation_chords_-_Buie_2025_et_al._Fig_5.jpg · Wikimedia Commons · See Wikimedia Commons
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
- Johann Palisa
- Discovery site
- Vienna Obs.
- Discovery date
- 21 September 1887
- Pronunciation
- / dʒ ʌ ˈ s t ɪ ʃ i ə /
- Named after
- Justitia
- Alternative designations
- A887 SA, 1942 XY
- Minor planet category
- Main belt ( middle ) · background
- Aphelion
- 3.179 AU
- Perihelion
- 2.048 AU
- Semi major axis
- 2.613 AU
- Orbital period sidereal
- 4.22 yr (1,543 d)
- Mean anomaly
- 244.365 °
- Mean motion
- 0° 13 59.88 / day
- Inclination
- 5.477°
- Longitude of ascending node
- 156.503°
- Argument of perihelion
- 120.144°
- Dimensions
- 64.60 × 58.34 × 46.60 km, ± (2.86 × 2.64 × 2.60 km)
- Mean diameter
- 57.0–57.8 km ( occultation ) , 58 ± 2 km ( thermophysical )
via Wikipedia infobox
~10 min read
Encyclopedic overview
269 Justitia is an asteroid located in the middle main asteroid belt. It was discovered on 21 September 1887 by Austrian astronomer Johann Palisa at Vienna Observatory and was named after Justitia, the Roman goddess of justice. The asteroid is about 58 kilometres (36 mi) in diameter and rotates relatively slowly, with a rotation period of 33.1 hours. Justitia is one of the targets of the United Arab Emirates' upcoming MBR Explorer mission, which will visit seven different asteroids in the asteroid belt during the 2030s. MBR Explorer is planned to enter orbit around Justitia via rendezvous in 2034 and will end its mission after dropping a lander to the asteroid's surface in 2035.
Justitia is unusual in that it has a much redder color compared to any other asteroid in the asteroid belt. Spectroscopic observations show that Justitia's color and composition appears to resemble those of centaurs and trans-Neptunian objects from the outer Solar System, whose surfaces are composed of ices and complex organic compounds (tholins). Hence, researchers believe that Justitia originated from the outer Solar System and then migrated inward to its present-day location in the asteroid belt. Only a few other asteroids have been identified to exhibit very red colors like Justitia, with 203 Pompeja and 732 Tjilaki as examples from the main asteroid belt.
Excerpted from Wikipedia’s “Q149966” article, available under the CC BY-SA 4.0 licence.