The Russian radio astronomy satellite, ``RadioAstron'', is in the construction phase in Russia. The engineering prototype of the radio frequency (RF) modules used in the satellite were brought to the US at the invitation of JPL and NRAO for compatibility tests. The equipment was in Green Bank from May 21 thru May 28, 1999, and then traveled to JPL in Pasadena for further tests. These tests are part of a series of pre-launch compatibility tests, including tests conducted in Green Bank and JPL in March 1993  and Moscow, Russia in October 1998 .
The tests were initially scheduled to follow a pre-established plan similar to the Japanese VSOP tests carried out in March 1996 . Initially, the Russian RF modules were set up in the laboratory for preliminary checks. The Russian modules were then installed in the Green Bank Telescope (GBT) control room on the second floor of the Jansky Lab addition. They were then radiatively coupled to the NRAO OVLBI earth station via two horns placed on the balcony outside the GBT control room. Nearly all of the tests were done with the RadioAstron RF modules locked to the earth station uplink signal. In all of these tests, formatted data for the wideband downlink was simulated by the NRAO Test Fixture  and supplied to the Russian modulator; the Russian Formatter assembly, which will supply this data during flight, was not included in the equipment being tested.
Yury Korneev of RISDE and Alexander Smirnov and Boris Kanevsky of ASC participated in the tests. They accompanied the Russian test set equipment to the United States, set up the test equipment and supervised its operation.