NASA Logo, National Aeronautics and Space Administration
NASA Space Science Data Coordinated Archive Header

Gamma-Ray Spectrometer

NSSDCA ID: 1971-063A-08

Mission Name: Apollo 15 Command and Service Module (CSM)
Principal Investigator:Dr. James R. Arnold


This experiment, carried on the command module of the Apollo 15 mission, was used to conduct a geochemical mapping of the lunar surface by observing the emitted gamma radiation from the lunar surface. During the transearth coast phase of the mission, this experiment was used for gamma-ray astronomy. The instrument consisted of a thallium activated sodium iodide scintillation crystal enclosed in a plastic scintillator sheild. The shield was placed in anticoincidence with the sodium iodide crystal to prevent events caused by charged particles. In normal operation, the instrument was deployed on a 7.6-m boom to decrease the response of the instrument to cosmic-ray interaction and radioactive sources in the spacecraft. The instrument responded to gamma rays from 0.5 to 30 MeV and had an energy resolution of 8.5 percent. The angular resolution of the lunar surface was approximately 2 to 3 deg, or 70 km.

Alternate Names

  • Apollo15CSM/Gamma-RaySpectrometer
  • S160


  • Astronomy: Gamma Ray
  • Planetary Science: Geology and Geophysics

Additional Information

Questions and comments about this experiment can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Mr. L. E. JamesGeneral ContactNASA Johnson Space Center
Dr. Jacob I. TrombkaOther InvestigatorNASA Goddard Space Flight Center
Prof. Laurence E. PetersonOther InvestigatorUniversity of California, San
Dr. Albert E. MetzgerOther InvestigatorNASA Jet Propulsion
Dr. James R. ArnoldPrincipal InvestigatorUniversity of California, San
[] NASA Logo -