Jumpseat signals intelligence satellites are launched by Titan 3's into Molniya-type orbits. These orbits are very similar to those of SDS classified communications satellites, and identification of a launch in either series as SDS or Jumpseat may differ from analyst to analyst.

Total Mass: 700 kg.

SDS 4 not deployed.

• 2 - McDowell, Jonathan, The United Nations Registry of Space Objects, Harvard University, 1997. HTML when accessed: http://hea-www.harvard.edu/QEDT/jcm/space/un/un.html
• 6 - JPL Mission and Spacecraft Library, Jet Propulsion Laboratory, 1997. HTML when accessed: http://msl.jpl.nasa.gov/home.html
• 279 - McDowell, Jonathan, Launch Log, October 1998. HTML when accessed: http://hea-www.harvard.edu/~jcm/space/log/launch.html