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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
- James Craig Watson
- Discovery date
- 10 October 1874
- Pronunciation
- English: / dʒ u ˈ eɪ w ɑː / joo- AY -wah , Mandarin: [ɻwe ̂ ɪxwa ̌ ]
- Alternative designations
- A874 TA
- Minor planet category
- Main belt
- Observation arc
- 121.07 yr (44222 d)
- Aphelion
- 3.26884 AU (489.012 Gm )
- Perihelion
- 2.29261 AU (342.970 Gm)
- Semi major axis
- 2.78073 AU (415.991 Gm)
- Orbital period sidereal
- 4.64 yr (1693.7 d )
- Mean anomaly
- 60.2817 °
- Mean motion
- 0° 12 45.187 / day
- Inclination
- 10.9127°
- Longitude of ascending node
- 1.83417°
- Argument of perihelion
- 165.566°
- Dimensions
- 148.3 ± 4.3 km × 142.3 ± 15.6 km
- Mean diameter
- 151.116 ± 1.596 km , 161.43 ± 7.38 km
- Mass
- (5.54 ± 2.20) × 10 kg , (3.262 ± 0.778/0.933) × 10 kg
via Wikipedia infobox
~1 min read
Encyclopedic overview
139 Juewa (/dʒuˈeɪwɑː/ joo-AY-wah) is a very large and dark main belt asteroid. It is probably composed of primitive carbonaceous material. It was the first asteroid discovered from China.
Juewa was discovered from Beijing by the visiting American astronomer James Craig Watson on 10 October 1874; Watson was in China to observe the transit of Venus. Watson asked Prince Gong to name the asteroid. Gong's choice was 瑞華星 (roughly, "Star of China's fortune"). Watson used the first two characters ('star' being redundant), transliterating them Juewa in Wade convention of the time. (In pinyin, 瑞華 is transliterated ruìhuá.)
Excerpted from Wikipedia’s “139 Juewa” article, available under the CC BY-SA 4.0 licence.