The Indian Space Research Organisation (ISRO) is going to undertake the heaviest ever commercial mission undertaken by it when the country's workhorse the Polar Satellite Launch Vehicle (PSLV) will put in orbit five foreign satellites from the spaceport of Sriharikota in Andhra Pradesh on July 10 this year, the overall lift-off mass of the five satellites amounting to about 1,440 kg and hence it would be the heaviest commercial mission.