The second crucial launch of a Proton booster featuring new phase two engines was set for 23 June, paving the way for the launch of the Zvezda service module to the International Space Station on 12 July. The booster was due to carry the Express 3A communications satellite payload.
The Russian Space and Aviation Agency and NASA have cleared the launch of Zvezda pending the successful second flight of the Proton with phase two second and third stage engines. The 19,050kg (42,000lb) 13m (43ft)-long Zvezda module, with four docking ports, should have flown in April 1998.
The first flight with phase two engines was conducted on 6 June, carrying a Gorizont satellite. The critical second launch was to have carried the Geyser military satellite on 20 June. It was delayed when the satellite was not ready, forcing the switch to the Express 3A payload. This was originally due to have flown on a Proton with phase one engines which had been manufactured before the two Proton failures last year.
A Sirius communications satellite is also set for a Proton launch on 29 June-1 July, also with phase one engines. The Geyser satellite will fly on around 7 July aboard a Proton with phase one engines, to be followed by Zvezda.
Source: Flight International
