Post Tue Jul 19, 2011 9:48 am

Russia and China hold the last space week's headline

On the 2nd of September, the Baikonur Cosmodrome was the host of a new Proton rocket's flight. The rocket, in the Block DM 2 configuration, carried to orbit three Glonass M satellites built by Information Satellite Systems Reshetnev Co. for the Russian Space Agency.

The Proton launcher left Kazakhstan from the hangar 81 at 00:53 GMT, injecting the three navigation satellites into a circular orbit with the inclination of 64.8 degrees, after a flight of about three and a half hours (separation occurred at 4:26 GMT). The three satellites have become active under the Cosmos 2464, 2465 and 2466 tokens.
This was the last M Class trio launched. In the future, more modern K Class satellites are expected to be launched instead.

Some time ago we reported about the launches from December 14, 2009 (when the Cosmos 2456, 2457 and 2458 were sent into orbit for the orbital plane no.1- slots 1, 4, 5) and from March 1, 2010 (when the orbital plane no. 3 was updated with three Cosmos satellites -2459, 2460 and 2461).
We also reported the problems that Glonass system has encountered last year, too. Glonass 2404, which has been launched in 2003, has been declared "unhealthy" on June 18, 2009, afterwards being abandoned. On May 13, Glonass 2435, a satellite which has been launched in 2007, also had technical problems but was partially recovered in August. However, its signals are still affected by disturbances and, in consequence, the satellite is not fully usable. On August 31st, Glonass 2444 also stopped functioning, even though it was launched recently in 2008. Finally on November 2nd the network lost the Glonass 2418, too.

The new satellites are going to become operational in maximum 45 days and have an operating lifetime estimated at seven years.
With the dimensions of 2.4 metres x 3.7 metres and having the solar panels span up to 7.2 meters, the satellites weigh 1480 kg each. The satellites which are three axes stabilized have the solar panels automatically held in the direction of the Sun while the main platform is aligned to Earth to facilitate the observation and communication.

The Proton rocket, which came into operation under the UR500 token, made the debut in a flight on July 16th, 1965. Since then it has managed to make 350 flights serving the most complex scenarios: it was used to launch Russian interplanetary missions to the Moon, Mars, Venus and Halley Comet, it transported different carriage to Mir stations and to ISS today and transported all types of commercial and military satellites into orbit.
This version of the Proton M rocket is 53 meters long and weighs 712 tons in nominal configuration.
It is a three stages rocket and has a system of boosters with a length of 42.3 m and a diameter ranging between 4.1 m and 7.4 m.
Additional control systems for orbital injection are present and differ accordingly to the mission specific. In this case, a Blok DM 2 system was used this one being equipped with a RD58M engine developing 85 kN of traction force.
The first stage of the rocket is powered by six RD 275 engines with a force of 10.5 MN, the second stage is powered by four engines type RD210 with a force of 2.3 MN and the third stage by a RD212 type engine with a force of 0.6 MN.
In this configuration the rocket is able to lift to orbit a payload of up to 22 tones in case of LEO missions or up to six tons for a GTO (geostationary transfer orbit) mission.
For the Thursday launch the first stage of the rocket flew for about 2 minutes, and after 10 minutes from take off, the third stage launched the Block DM 2 ensemble together with the satellites into an intermediary transfer orbit. Two successive activations of the ensemble took the satellites to the desired altitude of 19100 km and an inclination of 64.8 degrees, later followed by separation.

The Glonass system should have today 21 operational satellites, according to official information, including here the ones needed for a complete coverage of the Russian Federation (18) plus some additional platforms (for extending services to a global scale, 24 satellites are required instead), although the previous report of the Russian Space Agency in the early 2009 spoke of the system coverage of 95% for the Russian Federation and 83% globally.
The Glonass System (“Globalnaya Navigationnaya Sputnikovaya Sistema” or “Global Orbiting Navigation Satellite System”) was put into operation for the first time in September 1993 with a group of 12 satellites and has reached its projected number of 24 satellites in December 1995. However, due to financial problems at that time and the lack of new investment, some satellites have been retired without being replaced.
The system consists of three orbital planes separated by 120 degrees, with satellites in the same plane separated at 45 degrees. Each satellite is in an orbit situated at an altitude of 19100 km and an inclination of 64.8 degrees, and has an orbital period of 11 hours and 15 minutes. Satellites are identified uniquely by their so-called “slot number”: the first orbital plane contains slots 1 – 8, 9 – 16 the second and 17 – 24 the third.
Each satellite sends two types of signals: a standard one, accessible to business applications, and a coded, high-precision one dedicated to military use. There are, in fact, 25 channels separated by 0.5625 MHz in the frequency bands called L1: 1602.5625 - 1615.5 MHz and L2: 1240 - 1260 MHz.
According to official information, when the system will be complete, it will reach a maximum positioning error of up to 70 meters both horizontally and vertically, and the speed error will have a maximum of 15 cm/s ( in the civilian system), while the error decreases to 10 – 20 meters in the military system.
In order to keep track with competing navigation satellite systems, the Glonass System will benefit from an investment of 2.6 billion dollars, hopefully reaching a number of 30 operational satellites in the late 2011.
This change in the system’s design follows a study performed in 2007, when the expansion of the system from 24 to 30 satellites (8 operational and 2 spares per plane) has been foreseen.
The new generation of satellites, Glonass-K, which will be released starting with the second half of 2010, benefits from an improved design that should increase its operation period to 10 – 12 years and in parallel its reliability. They should be smaller and lighter (750 kg) which will allow the usage of Soyuz-2 as launcher, to the detriment of Proton-M, thus reducing the launching cost to half.

China managed to put into orbit on September 4th its newest platform for the China Satcom company – the sixth satellite from the Sinosat telecommunication series.
This geostationary satellite weighs 5 tones and will operate for approximately 15 years from the 125 degrees East orbital position, 24 transponders in C band, 8 in Ku band and one in S band, which should be able to serve the whole country's territory.
It is built on the basis of DFH-4, a versatile platform that can integrate up to 600 kg of communication equipment, with a necessary power of about 10.5 kW. Launched from the Xichang Satellite Launch Center in the south-western China, at 16:14 GMT, the Long March CZ-3B (Chang Zheng-3B) rocket carried the satellite into a geostationary orbit with the inclination of 25 degrees.
Before becoming operational, the satellite must apply a series of orbital maneuvers in order to enter a circular orbit and decrease the inclination of the orbital plane.
CZ-3B is a three stage rocket (four YF20C engines in the first stage, one YF24E engine in the second stage and one YF75 engine in the last stage) and additionally powered by four boosters YF25. With a height of 54.8 meters and a diameter of 3.35 meters, the rocket is able to carry a 12 tones payload to LEO or 5.1 tones payload to a GTO.
Chinese space program has two major directions: development of new satellites and the development of a human flight program, but an equally important problem remains the progressive enlargement of the launching capacity in order to have the necessary logistics for these projects.
China currently relies solely on the capacity of LongMarch ( now in the 4th series) and on the future 5th series which should increase the mass sent onto a low orbit to 25000 kg or alternatively 14000 kg to a geostationary orbit (in the most powerful configuration).