North Ray (crater)

North Ray
Apollo 16 image
Coordinates8°49′S 15°29′E / 8.82°S 15.48°E / -8.82; 15.48
Diameter950 m[1]
Depth240 m
EponymAstronaut-named feature
LRO image

North Ray crater is a small crater in the Descartes Highlands of the Moon visited by the astronauts of Apollo 16. The name of the crater was formally adopted by the IAU in 1973.[1] It is the largest crater sampled by astronauts during the Apollo program.

The Apollo 16 Lunar Module (LM) Orion landed between North Ray and South Ray craters on April 21, 1972. The astronauts John Young and Charles Duke explored the area between the craters over the course of three EVAs using a Lunar Roving Vehicle, or rover. They visited North Ray on EVA 3, at station 11, about 4.4 km north of the landing site. On the way, they drove along the rim of the similar sized but older crater Palmetto, which is approximately 3 km south of North Ray.

North Ray crater is approximately 1 km in diameter and approximately 240 m deep.[2] The astronauts observed that the upper 50 m of the slope is gentle, but that it becomes steep below 50 m, and they could not observe the bottom. The inner slopes are covered by boulders up to 5 m across. A huge (10 m high x 20 m long) boulder, known as House Rock, lies near the southeastern rim. A smaller boulder that is almost certainly a fragment of House Rock is officially known as South Boulder, but unofficially known as Outhouse Rock.[3] The ray system, which can be seen from orbit, was not obvious on the ground.

North Ray cuts into the Cayley Formation of Imbrian age,[4] but the crater itself is much younger, of Copernican age, based on the presence of rays. (See also section on age below.)

Panorama of North Ray Crater from the south rim. House Rock is at right edge. Compare with the map below.
Planimetric map of Station 11 from the Apollo 16 Preliminary Science Report. X indicates sample locations, 5-digit numbers are LRL sample numbers, rectangle is lunar rover (dot indicates TV camera), black spots are large rocks, dashed lines are crater rims or other topographic features, and triangles are panorama stations.
  1. ^ a b North Ray, Gazetteer of Planetary Nomenclature, International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN)
  2. ^ Apollo 16 Landing Area, 78D2S1(50), NASA Lunar Topophotomap. Published by The Defense Mapping Agency, November 1974. Available from Lunar and Planetary Institute.
  3. ^ Apollo 16 Preliminary Science Report (NASA SP-315), 1972
  4. ^ Geologic Map of the Apollo 16 (Descartes) Landing Area by Apollo Field Geology Investigation Team (D. P. Elston, E. L. Boudette, J. P. Schafer), United States Geological Survey, April 1972