File:39_Laetitia_Image.png · 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
- J. Chacornac
- Discovery date
- 8 February 1856
- Pronunciation
- / l ɛ ˈ t ɪ ʃ i ə /
- Named after
- Laetitia
- Minor planet category
- Main belt
- Aphelion
- 461.503 million km (3.085 AU)
- Perihelion
- 366.877 million km (2.452 AU)
- Semi major axis
- 414.190 million km (2.769 AU )
- Orbital period sidereal
- 1,682.713 d (4.61 a )
- Mean anomaly
- 58.261°
- Inclination
- 10.383°
- Longitude of ascending node
- 157.168°
- Argument of perihelion
- 209.560°
- Dimensions
- 219 km × 142 km 149.5 km 153.80 ± 4.14 km
- Mass
- (4.72 ± 1.14) × 10 kg
- Mean density
- 2.47 ± 0.63 g/cm
- Synodic rotation period
- 0.2141 d (5.138 h)
- Geometric albedo
- 0.287 ( geometric )
via Wikipedia infobox
~2 min read
Encyclopedic overview
39 Laetitia photographed in December 2020 39 Laetitia is a large main-belt asteroid that was discovered by French astronomer Jean Chacornac on 9 February 1856 and named after Laetitia, a minor Roman goddess of gaiety. The spectrum matches an S-type, indicating a stony (silicate) composition. It is orbiting the Sun with a period of 4.61 years and is spinning on its axis once every 5.1 hours.
Photometric observations of this asteroid gathered between 1968 and 1974 were used to build a light curve that provided shape and rotation information. It has the general shape of an elongated triaxial ellipsoid with ratios between the lengths of the axes equal to 15:9:5. Major surface features are on a scale of 10 km and the surface color does not vary significantly across the surface. In the ecliptic coordinate system, the pole of rotation is estimated to be oriented to the coordinates (λ0, β0) = (121°±10°, +37°±10°).
Excerpted from Wikipedia’s “39 Laetitia” article, available under the CC BY-SA 4.0 licence.