NSSDC Master Catalog Display
Experiment

Suprathermal Ion Detector Experiment (SIDE)

NSSDC ID: 71-008C-06
Mission Name: Apollo 14 LM/ALSEP
Principal Investigator: Freeman

Description

This experiment, part of the ALSEP package, measured positive ions reaching the lunar surface, including magnetospheric ions and those generated from ultraviolet ionization of the lunar atmosphere and from the free-streaming solar wind/lunar surface interaction. Similar instruments, differing only in look direction and mass range, were also flown on Apollo 12 and 15. Flux, number density, velocity, and energy/unit charge were determined. A low-energy curved-plate mass analyzer (MA), with a velocity filter of crossed -E and -B fields determined the ion flux in 20 mass channels up to 750 amu per charge for 6 energies over the range 0.2 to 48.6 eV. Another analyzer, the total ion detector (TID), did not have a velocity filter and detected higher energy ions in 20 steps over the range 10 to 3500 eV. A mass spectrum (from MA) and an energy spectrum (from TID) were obtained each 24 s in normal mode. The potential of the entrance apertures relative to a grid deployed on the lunar surface was normally varied through 24 steps at 2.58 min/step, in order to monitor the lunar surface potential. The detectors looked upward, 15 deg from local vertical, in a plane parallel to the lunar equator. The sensors looked approximately 2.4 deg to the right of Earth, so solar wind ions were not directly observeable while the moon was outside the magnetosphere. Streaming ions in the downstream dawn-side magnetosheath were observed, as were ions upstream from the bow shock. An instrument description and preliminary report is given by Hills and Freeman as section 8 of the Apollo 14 Preliminary Science Report, NASA SP-272, 1971.

Discipline(s)

    Planetary Science/Fields and Particles
    Planetary Science/Small Bodies
    Space Physics/Magnetospheric Studies

* Personnel Information

* Data Set Information
* Mission Information
* Go to the NSSDC Planetary page
* Go to the NSSDC Space Physics page

* Go to the NSSDC home page

[Logo]
For questions about the NSSDC's information systems, please contact:
Dr. James Thieman, thieman@nssdca.gsfc.nasa.gov, (301)286-9790
National Space Science Data Center, Code 633.2
NASA/Goddard Space Flight Center, Greenbelt, MD 20771
NASA Official: J. H. King, king@nssdca.gsfc.nasa.gov
Last Updated: 1996-12-19
Output Generated: 1997-09-25
Programming by: E. V. Bell, II