Chandrayaan moving the right way

Preliminary design of ISRO's spacecraft complete; may take off in 2007

The first phase of preparations for Chandrayaan-1, India's first scientific mission to the moon, is completed and the project is moving in the right direction.

According to the Indian Space Research Organisation (ISRO) sources, groundworks like the selection of payloads (both Indian and European Space Agency), design review of the spacecraft bus, payloads and the Deep Space Network (DSN) to control the spacecraft have been completed. The Rs 386 crore project with a mission life of two years is expected to take off in 2007 as per schedule, it added.

During the last year, ISRO acquired 100 acres of land at Ramohalli, around 30 km from Bangalore, for the establishment of DSN project. The construction work of the project is presently underway by ISRO's civil engineering division and a budgetary sanction of Rs 100 crore has been allocated for the purpose.

ISRO sources said that the DSN would assist the mission in communicating with the lunar spacecraft, which will be located 4 lakh kilometres from the earth. The DSN will have a giant antenna of 32 metre diameter. The Electronic Corporation of India Ltd (ECIL) and Bhaba Atomic Research Centre (BARC) have been given the contract to design and develop the antenna.

Although ISRO has a Master Control Facility (MCF) located at Hassan in Karnataka, the facility has the capacity to track communication satellites up to a distance of 36,000 kilometre and can't be useful for Chandrayaan mission. This apart, although one more MFC has also come up at Bhopal in Madhya Pradesh, this was capable only to locate communication satellites, ISRO sources said.

The sources also said that a new strap-on motor (PSOM-XL), which is capable of carrying 12.4 tonne of solid propellant as against the present 9 tonne, had been tested successfully. The motor would give extra capacity to PSLV, which would place the lunar spacecraft in the orbit.

While the preliminary design of the lunar spacecraft has been completed successfully, the critical design was going to start soon.

"In this phase, it will take lot of time towards the configuration and finalisation of the spacecraft and its construction subsequently," the sources said.

During this period, if any technical problems or snags were located in the spacecraft, this would be thoroughly reviewed and repaired. The final designing would be done towards the end of the current fiscal which would give final touch to the mission, it added.

Apart from the six Indian payloads, ISRO has selected six other payloads out of the proposals received from the international community in response to an 'announcement of opportunity' proposal made by it earlier. "The idea is about collecting as much information about the moon as possible," a member of the mission team informed. The payloads have been finalised selectively which would help in collecting every bit of information about physical and chemical mapping of the moon, it added.

The Indian payloads that have been proposed to be included in the mission include a terrain mapping stereo camera (TMC), a hyper spectral wedge filter camera having 64 channels to take the pictures of narrow spectral band which are beyond the visibility of human being and a collimated low energy X-ray spectrometer for measuring fluorescent X-rays emanating from the lunar surface.

This apart, a solar X-ray monitor and a laser ranging instrument with height resolution of about 10 metres have been selected for chemical and surface mapping of the moon. The bands and wavelength of the cameras to be installed with the European payloads would be different from the Indian ones, it added.