Tim Furniss/LONDON
The failure of a domestic Russian launch of a four-stage Proton booster on 5 July has grounded International Launch Services (ILS) and casts doubts on a punctual launch of the International Space Station (ISS) Zvezda service module in November.
The US-Russian ILS Atlas fleet is already grounded as investigations continue into the failure of a Centaur-class RL-10 powerplant during a Delta III launch in May. Russia has grounded the Proton, also offered by ILS. "We hope the investigation will be short, but thorough," says ILS. NASA says it is "too early" to say whether the Zvezda flight will be affected.
ILS was due to launch the first ICO Global Communications satellite on a Proton in August and Eutelsat has cancelled its planned Proton launch of the new Sesat communications satellite at the end of this month.
The Zvezda launch is not expected until at least one Proton has flown successfully after the accident probe is complete, making it unlikely that the ISS' November deadline will be met, delaying further assembly missions.
Proton maker Khrunichev says the flight from Baikonur, in Kazakhstan, was normal until the second stage burn. Telemetry indicated "anomalous data" at T+280s at an altitude of 120km. The rocket deviated from its planned path at T+330s. It is thought that one of the second stage engines shut down prematurely, or that an explosion took place.
The booster was tracked 60s later, 14km below its planned trajectory. The disintegrating vehicle plunged to the ground, 1,050km from Baikonur, into a sparsely populated region of Karaganda, with the loss of the Raduga 1 military communications satellite and an untried Breeze M upper stage.
Five Protons have failed since 1990, but it has had 95 successful launches in the past 10 years, with a 92% reliability record, says Khrunichev. Since 1967, the four-stage Proton has made 202 flights, with 11 failures to reach the correct orbit and 20 total losses.
Source: Flight International
