Chandrayaan-1 on course for launch

Chandrayaan-1 on course for launch

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India – The sticker on the threshold just says, “Spacecraft checkout No.4.” As we entered the mezzanine-like floor on Monday and looked below, the gorgeous looking Chandrayaan-1, enveloped in golden yellow insulation foil, came into view.

It was in the dirt-free “clean room” of the ISRO Satellite Centre (ISAC), Bangalore, and men dressed in white overalls, were fussing over it and conducting checks. It had passed a battery of tests in the space simulation chamber (SSC), where it was subjected to extremes of hot and cold temperatures.

Tests that unfolded its solar panel, as if were an accordion, and for pointing its antenna were equally successful. It will now face vibration and noise tests. Things are moving ahead for the launch of Chandrayaan-1, India’s first spacecraft to the moon, before the end of October from Sriharikota by a Polar Satellite Launch Vehicle called PSLV-XL.

Chandrayaan-1 will carry 11 instruments, five from India and six from abroad. They will map the minerals and chemicals on the lunar soil and also provide clues to the moon’s origin.

ISAC Director T.K. Alex called it “a complicated mission” because “for the first time, we are sending a spacecraft beyond the earth’s orbit” (that is, it will orbit the moon). The moon is nearly four lakh km away and the spacecraft has to be manoeuvred precisely in stages to reach the moon’s orbit.

After all the 11 instruments were successfully integrated into Chandrayaan-1, it underwent thermo-vacuum tests in the special facility SSC.

The spacecraft was subjected to 120 degrees Celsius and minus 150 degrees Celsius in the chamber. “It was tested in varying temperatures for almost 20 days. The performance of the spacecraft and its instruments were thoroughly checked and we found that they were all working well,” said Dr. Alex.

M. Annadurai, Project Director, Chandrayaan-1, asserted that there were “no issues’ when the spacecraft went through thermo-vacuum tests, including “soak and shock tests.” During the “soak” tests, it was subjected to high temperatures for long durations. In “shock” tests, it alternately went through high and very low temperatures in quick succession. “During these tests also, we found that there was no issue and all the systems were working well,” Mr. Annadurai said.

He called the SSC a big contraption that “looks like a well.” It is four metres in diameter and seven metres in depth. It has a big lid.

Chandrayaan-1 is now getting ready for the vibration and acoustic tests from September 20. It will be placed on a shake-table. Mr. Annadurai said: “We will generate the vibrations that the spacecraft will undergo when it is launched by the PSLV. Then we move on to the acoustic chamber, where we generate noise similar to that made by the PSLV engines. The spacecraft has to withstand that also.”

While an aircraft engine produced 145 decibels of noise, the PSLV engines produced 150 decibels, Dr. Alex explained. “We are on course for transporting Chandrayaan-1 to Sriharikota by the end of this month (September),” Mr. Annadurai said.