Galileo Encounter with 951 Gaspra: First Pictures of an Asteroid

  title={Galileo Encounter with 951 Gaspra: First Pictures of an Asteroid},
  author={Michael J. S. Belton and Joseph Frank Veverka and Peter C. Thomas and P. Helfenstein and Damon P. Simonelli and Clark R. Chapman and Merton E. Davies and Ronald Greeley and Richard Greenberg and James W. Head and Scott L. Murchie and K. P. Klaasen and Torrence V. Johnson and Alfred S. McEwen and David R. Morrison and Gerhard Neukum and Fraser P. Fanale and Clifford D. Anger and Michael H. Carr and Carl Bernard Pilcher},
  pages={1647 - 1652}
Galileo images of Gaspra reveal it to be an irregularly shaped object (19 by 12 by 11 kilometers) that appears to have been created by a catastrophic collisional disruption of a precursor parent body. The cratering age of the surface is about 200 million years. Subtle albedo and color variations appear to correlate with morphological features: Brighter materials are associated with craters especially along the crests of ridges, have a stronger 1-micrometer absorption, and may represent freshly… 
Linear features on asteroid 951 Gaspra
Galileo images of asteroid 951 Gaspra reveal numerous linear ridges, crater chains and valleys. I describe? all visible linear features and assess their significance. A few crater chains may be
The surface of asteroid 951 Gaspra
I present new maps, photomosaics and geological interpretations of asteroid 951 Gaspra. Facets and limb concavities suggest a long history of large impacts producing 5 to 7 km diameter craters.
951 Gaspra: First Pictures of an Asteroid
On October 29, 1991, the Galileo spacecraft flew past 951 Gaspra at a distance of 1600 km and obtained the first close-up views of an asteroid. The best view of an asteroid ever taken (Figure 1) from
First Images of Asteroid 243 Ida
The first images of the asteroid 243 Ida from Galileo show an irregular object measuring 56-kilometers by 24 kilometers by 21 kilometers with high crater density and size-frequency distribution, indicating a surface in equilibrium with saturated cratering.
The Galileo Encounters with Gaspra and Ida
The Galileo spacecraft encounters with 951 Gaspra and 243 Ida have provided the first close-up pictures and measurements of asteroids. These two small, S-type asteroids are both irregular in shape,
Cratering on Gaspra
Abstract Galileo flyby images of 951 Gaspra show a crater population dominated by fresh craters several hundred meters in diameter and smaller. They must represent a production population because
Asteroid Geology from Galileo and NEAR Shoemaker Data
The four asteroids visited by spacecraft, Gaspra, Ida, Mathilde, and Eros, have shapes and surface morphologies dominated by the effects of impact cratering. The presence of impactderived regolith
The topography of Janus
A topographic model of Saturn's larger co-orbital satellite Janus was derived from the shapes of limbs and terminators in Voyager images, modified locally to accommodate large craters and ridges. The
Abstract Galileo images of Asteroid 243 Ida and its satellite Dactyl show surfaces which are dominantly shaped by impact cratering. A number of observations suggest that ejecta from hypervelocity


Galileo support observations of Asteroid 951 Gaspra
Observations of 951 Gaspra in support of the Galileo spacecraft encounter are reported. Photometric observations of the asteroid yield a synodic rotational period of 7.042 46 and a slope parameter G
951 gaspra: A pre‐Galileo estimate of its surface evolution
We attempt to quantitatively model the collisional environment and surface evolution of asteroid 951 Gaspra prior to the flyby of the Galileo spacecraft later this year. We compute Gaspra's average
Lunar spectral types.
The spectral reflectance properties (0.3–1.1 μ) of a number of lunar mare, upland, and bright crater areas were observed with the use of ground-based telescopes. These new data are discussed in view