Post Tue Jul 19, 2011 9:47 am

China is once again in the forefront of spatial launches

On 22nd of September we were reporting the launch of Yaogan 11 from Jiuquan space center and only a week later we can already speak about an intense campaign taking place in China, because in the meantime, two other launches were performed.

The first one Chang’e 2 is China’s second probe sent to the moon and was an investment of 134 million for the Chinese Space Program. It was initially built as a spare platform for Chang’e 1, in case it would have failed, but the scientific part was substantially improved afterwards.
It was launched symbolically on 1 October, on the Chinese national day, at 10:59 from hangar two of Xichang space base, aboard a Long March 3C rocket. The probe will continue its exploration of Earth’s satellite. The transfer period to the final polar orbit around the Moon (which will have a height ranging from 15 to 100 km and a period of 117 minutes) will be of about 5 days (or more accurately 122 hours), half the transfer period of Chang’e 1 (12 days). This change is mainly due to the increased orbital injection velocity of the CZ 3C launcher, compared to CZ 3A which was used in the previous flight. The speed allowed a direct placement of a Chinese satellite onto a transfer orbit to the Moon for the first time, without needing a fly-by around the Earth, as before.

According to the scenario, Wednesday at 3:06 UTC, took place the orbital injection maneuvers aiming an initial placing of the satellite on a high elliptical orbit, followed by two corrections meant to decrease the height of the orbit.

The first Chinese spacecraft, Chang’e 1, launched on 24 October 2007 aboard a Long March 3 launcher, successfully fulfilled its mission, collapsing on the lunar surface at 1.5 degrees south latitude and 52.36 degrees east longitude.
Its name comes from the Chinese mythology, representing an ancient Moon goddess. The purpose of the mission which lasted 16 months (except for obtaining maps of the moon) was to study the ability to adjust the trajectory and orbital degrees of freedom of the probe in the vicinity of the Moon. The tests were made by remote control, using two ground bases: Qingdao and Kashi.

The new satellite is going to gather high resolution images (1.5m-10m depending on altitude 15-100km, compared to 100m from the Chang `e 1 flying at 200 km altitude) for a minimum of 6 months with possibility of extension if things go well and will prepare the ground for Chang’e 3 which will fly in March 2013 (choosing sites favorable for landing) and later for manned missions.

Chang'e 2 is a 2480 kg satellite equipped with a new stereo-type HD CCD camera. On board there are two spectroscopes in x and gamma range that will allow investigation of the content and distribution of elements such as Al, Mg, Si, Ti, etc. in the lunar soil. By scanning the lunar surface using a so-called 'Microwave Detector' at frequencies of 3.0, 7.8, 19.35 and 37 GHz, Chang’e 2 will be able to collect additional information on soil properties.
The probe also has a solar particle and ion detector, which will allow the study of the influence of solar wind on the surface of the moon. For the first time, the satellite will bring in attention the use of X-band communications for ‘deep space’ missions, technology that is intended to be used for other future missions to Mars and Venus.

Ground network stations are placed at Kunming, Beijing and Urumqi (under the tutelage of National Astronomical Observatories of China), but the interesting thing is that the satellite’s antennas will be able to communicate equally with China Satellite Maritime Tracking & Network Control Department, whose spaceships Yuanwang 3.5 and 6 have compatible command and telemetry systems installed on-board.

A second release was made based on Tayiuan, Wednesday, October 6, 0:49 pm UTC using a Long March 4B rocket. Passengers were two satellites from the Shijian 6-1 class, a space designed experiments class, the 6G and 6H platforms. They come at two years time since the last release (October 2008) and will fly in an orbit with an altitude of 640 km and inclination of 98 degrees. The Shijian satellite class launching scenario is classic and is carried on board a CZ-4B missile involving a dual flights. The first flight took place in September 2004 when platforms 6A and 6B were launched. The second one took place in October 2006 with 6C and 6D platforms and the third one which we mentioned earlier in October 2008 with 6E and 6F satellites.
This was the second release of the year from the Tayiuan base and the 11th of the Chinese space program in 2010.

The two new satellites were built for the China Aerospace Science and Technology Corporation by the Shanghai Academy of Space Flight Technology, China Electronics Technology Corporation and Dongfanghong Satellite on a CAST968 platform, and their lifetime should be somewhere around two years. The next Chinese launch will most likely take place on the 30th of October, when is expected that a new Beidou 2 navigation satellite (platform with 4G telecom capabilities) will be put into orbit by a CZ-3C rocket. The previous launch of a satellite of this kind took place in June.