N-4 Spacecraft Cutaway view of N-4 spacecraft. This heavy high-energy physics station was launched on the first four test launches of the Proton launch vehicle. Credit: Chelomei School, Leninsk. 30,376 bytes. 525 x 345 pixels.

Cosmic ray measurements. Study of the nature of high and ultra-high energy cosmic rays and their interaction with atomic nuclei. Mass announced at time of launch 17,000 kg. Scientific payload 12,500 kg; operated for 100 days in orbit.

Total Mass: 16,000 kg. Total Payload: 12,500 kg.

First launch of the Proton three-stage variant. The satellite studied the nature of high and ultra-high energy cosmic rays and their interaction with atomic nuclei. Scientific payload 12,500 kg; operated for 100 days in orbit.

• 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
• 67 - Kaesmann, Ferdinand, et. al., Journal of the British Interplanetary Society, "Proton - Development of A Russian Launch Vehicle", 1998, Volume 51, page 3.