The Khrunichev State Space Scientific Industrial Center has postponed the first flight of the Proton-M launch vehicle for early June, due to some malfunctions in the rocket system discovered during pre-flight preparations at the Baikonur cosmodrome. The Proton-M is the latest iteration of the successful launch vehicle first flown in 1965.
In 1967 the Soviet Union made the first successful launch of the three-staged Proton-K. Since then the K variant, available in three and four stage configurations, has played the main role in many Russian and international space projects, including orbital space stations. Able to put a 20 t load into a low orbit, the Proton-K deployed the Mir space station and, more recently, the Functional Cargo Block (FGB), the first element of the International Space Station (ISS).
In 1995 the rocket became available on the international market for launch services. That year Khrunichev and Lockheed-Martin established a joint venture, called International Launch Services (ILS). ILS accepts orders for inserting commercial satellites into orbit using the Proton and its US counterpart Atlas. By teaming up with the Russians, the US space industry achieved parity with the Western Europe's Arianespace, offering the Ariane-4 and 5 launch vehicles. Reflecting the change in the market situation, Arianespace's share in the commercial sector of geostationary launch services dropped from 50% in 1997 down to 30% in 1999.
In accordance with US/Russian interstate agreements signed in 1993 and 1996, Proton commercial services were limited to 16 launches by the year 2000. This quota will have been used up in September this year, with the launch of the LMI-1 satellite belonging to Lockheed-Martin Intersputnik. Remarkably, the LMI-1 flight will be the first commercial use of the Proton-M. Before that, however, the upgraded rocket has to deploy a Raduga series spacecraft belonging to the Russian defence ministry.
So far, Proton commercial launches have generated about $1.5 billion in sales. The main agrument in favour of the Russian rocket is its high reliability, at 97 percent, reflected over about 250 launches. The Proton came timely onto the international market, which, since the early 1990s, has been showing a growing demand in launch vehicles able to deploy communications satellites into geostationary orbits (36000 km in height).
The Proton-K put its first satellite into geostationary orbit in 1974. Since then, it has remained the only Russian rocket able to do so. To have the required capability, the Proton-K was fitted with the D boosting block, which later was replaced by the DM. With the latter block in place, the rocket can put a 2.6 t load into geostationary orbit. Unlike Western launch vehicles that deploy satellites into so-called geotransfer orbits, the Russian rocket can put them directly into geostationary orbit, thus eliminating the need of an apogee propulsion system to be installed on the satellite.
In the late 1980s the leading communications companies began asking launch providers for deployment into geotransfer orbit of heavy satellites weighing up to 5 t. This requirement made Arianespace introduce the Ariane-5. Khrunichev replied with the Proton-M project, launched in 1994. The M differs from the K in having the Breeze-M boosting block in lieu of the DM. This provides an increase in the geostationary capability from 2.6 to 3.3 t, and up to 5 t in the case of satellites with a built-in apogee motor.
The Breeze-M is a derivative of the Breeze boosting block developed for the Rokot light launch vehicle, a conversion of the RS-18 intercontinental ballistic missile known in the West as the SS-19 Satan. So far, there have been three successful Rokot launches, which gives Khrunichev hopes of trouble-free introduction for the Breeze-M. In 1996 Khrunuchev began construction of Breeze-M blocks at its manufacturing facility in Moscow. By December 1998 the first block was assembled, tested and shipped to the Baikonur cosmodrome.
Despite the outstanding reliability and low cost, the end of the Proton career is already in sight. The Khrunichev space center is now working on the 750-t Angara launch vehicle with a geostationary capability of 5 t. The major advantage of the new rocket is its ability to use the existing Zenit launch sites, and thus be able to fly from the Plesetsk cosmodrome. Before the Angara becomes available, which might happen in 2004 at the earliest, Russia will make do with the "old but gold" Proton. Most likely, the aging rocket will continue in service until the year 2010.
