A senior official at the Indian Space Research
Organisation (ISRO) has candidly admitted that scientists
miscalculated the temperature of the moon and that this had led to
the early termination of the Chandrayaan-I mission last month.
K Alex, director, ISRO Satellite Centre, Bangalore, said: “We
assumed that the temperature at 100km above the Moon's surface would
be around 75 degrees Celsius. However, it was more than 75 degrees
and problems started to surface. We had to raise the orbit to
May, ISRO said it had raised Chandrayaan's orbit to "enable further
studies on orbit perturbations, gravitational field variation of the
Moon and also enable imaging of the lunar surface with a wider
now transpires that heating problems on the craft had begun as early
as November 25, 2008, forcing ISRO to deactivate some of the
payloads - there were 11 in all.
result, some of the experiments could not be carried out which
raised questions on whether the pre-launch thermal vacuum test done
on the spacecraft at the ISRO Satellite Centre in Bangalore was
early 2009, the situation improved and Chandrayaan-1 started
operating normally. However, the snags resurfaced. This time with
the two star sensors of Chandrayaan because of high temperature. The
sensors are crucial in determining the orientation of the craft in
first star sensor packed up on April 26, and even the back-up sensor
failed during the second week of May.
officials said scientists and engineers used ingenious ways to
restore Chandrayaan-I by using gyroscopes as a temporary step.
official said much before the official announcement of the project's
end on August 30, it had become clear that the two-year mission
would be cut short since 95 percent of the scientific goals had been
ISRO claims that 95% of its planned experiments have been completed,
it remains to be known whether payloads designed to operate at a
100-km orbit completed their missions. The issue has triggered a
fierce debate on whether ISRO should have declared it a one-year
mission right at the beginning rather than an ambitious two-year