It is predicted that the storm of meteoroids, associated with Comet 55P/Temple-Tuttle, would be at its peak around 0210 hrs (IST) on November 18 and is expected to last a couple of hours on either side of its peak. During the peak of the storm, zenithal hourly rate may reach about 1,50,000 particles per hour, according to an ISRO press release here today. ``Though the possibility of the satellites getting hit by meteoroids debris is small, ISRO is taking all necessary precautions to minimise the impact of the meteoroids, if any'', the release added.

India's INSAT satellites are placed in geostationary orbit, about 36,000 km over the equator while the Indian remote sensing satellites (IRS) are placed in polar orbits of 820 km to 900 km. The probability of these satellites being hit by themeteoroid debris, which will be encountered at a relative velocity of about 71 km per second is estimated to be between 0.01 per cent to 0.03 per cent. Without taking any chances, ISRO would take a series of measures to protect its five INSATs (INSAT-1D, INSAT-2A, INSAT-2B, INSAT-2C and INSAT-2DT) and four IRS satellites (IRS-1B, IRS-1C, IRS-1D and IRS-P3) besides the scientific satellite, Sross-C2.

The release said the risk from the storm could be physical, mechanical and electrical damage to the satellites resulting in mechanical cratering, plasma or electro static discharges. ISRO would closely monitor the health of all its satellites from the spacecraft control centres (ISTRAC in Bangalore for IRS and Sross satellites and master control facility at Hassan for INSAT satellites) to detect any electrical anomalies during the period. The designers of various satellite sub-systems would be present at these spacecraft control centres to guide any corrective operations, if necessary.

The solar panels of thesatellites would be oriented in such a way that they present minimum surface area to the approaching meteoroid debris. Some of the operations like the panchromatic camera steering on board IRS-1C and IRS-1D would be avoided during the meteoroids storm. The operation of X-ray payload on IRS-P3 and the Gamma-ray instruments on board Sross-C2 satellite, which involve high voltages, would also be suspended during the period. Only essential equipment would be kept on during the period. The gyros on board Insat would be kept on to closely monitor the body movement rates to detect any meteoroids hits.