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




The HILAT spacecraft (also known as P83-1) was a refurbished TRANSIT S/C which carried experiments intended to provide remote-sensing and in situ measurements of physical quantities likely to provide insight into the dynamics of plasma-density irregularity formation in the high-latitude ionosphere. The main objectives of the HILAT mission were (1) to extend the data base on irregularity strength and three-dimensional shape, (2) to probe several hypotheses about the development, transport, and decay of scintillation-producing irregularities, (3) to document the role of convective instabilities at high latitudes, and (4) to describe the role of peculiarly high-latitude influences such as particle precipitation and other aspects of ionospheric/magnetospheric coupling.

The satellite was three-axis stabilized by means of a TRANSIT gravity-gradient boom and an added momentum wheel for yaw stabilization. The altitude was selected to be sufficiently high for scintillation and imager operation but low enough for the various in situ measurements. The inclination was chosen to give overhead passes nearly along the geomagnetic meridian at the preferred receiving locations. The orbit precessed 24 hours in approximately 6 months, so that observations during all hours of the day and night were possible in roughly one calendar season.

The Langmuir probe instrument failed on launch, and the Auroral imager failed on 23 July 83. All other instruments functioned until the final failure of the power source on 5 June 89.

For more details, see article in Johns Hopkins APL Technical Digest, Volume 5, #2, page 104, (1984), by K.A. Potocki, entitled, "The HILAT Spacecraft".

Alternate Names

  • STP P83-1
  • P83-1
  • 14154

Facts in Brief

Launch Date: 1983-06-27
Launch Vehicle: Scout
Launch Site: Vandenberg AFB, United States
Mass: 248.3 kg

Funding Agencies

  • National Research Council of Canada (Canada)
  • Department of Defense-Department of the Air Force (United States)


  • Space Physics

Additional Information

Questions and comments about this spacecraft can be directed to: Dr. H. Kent Hills



NameRoleOriginal AffiliationE-mail
Mr. Kenneth A. PotockiProject ManagerApplied Physics Laboratory
Dr. Edward J. FremouwProject ScientistPhysical Dynamics, Inc
[] NASA Logo -