Chennai, Dec 2 (Reporter) The T-25 hour countdown for the launch of European Space Agency's (ESA) two satellites as of part Proba-3 mission onboard ISRO's reliable and workhorse launch vehicle PSLV from Satish Dhawan Space Centre, SHAR Rage, Sriharikota on December four, will begin at 1508 hrs tomorrow. The launch of Proba-3, the world's first precision formation flying mission that will study the solar corona, the Sun's outermost layer, will take place from the Indian spaceport of Sriharikota at 1608 hrs on Wednesday evening Indian Space Research Organisation (ISRO) sources said Proba-3 will be carrying two satellites, the 200 kg Occulter Spacecraft (OSC) and the 340 kg Coronagraph Spacecraft (CSC). ISRO will be using its XL version of PSLV for the mission and the two spacecrafts will be injected into a high elliptical orbit at an apogee of 60,530 km and a perigee of 600 km with an inclination of 59 degrees in a stack configuration. During the countdown, propellant filling operations--solid and liquid propellants--will be carried out in the four-stage vehicle. In a post on X, ISRO said "the trusted PSLV is ready to shine with the PSLV-C59/PROBA-3, a mission by New Space India Limited enabled by ISRO, in collaboration with ESA. This mission will place ESA’s PROBA-3 satellites (about 550kg) into a unique highly elliptical orbit, reinforcing PSLV’s reliability for complex orbital deliveries." The orbital period will be 19.7 hours and the Mission antenna will be at Santa Maria des Azores, and ground station at Redu, Belgium. The twin satellites will fly together, maintaining a fixed configuration as if they were a single large rigid structure in space, to prove formation flying and rendezvous technologies, ESA said. Flying together, a pair of spacecraft will form an artificial solar eclipse in space, casting a precisely-controlled shadow from one platform to the other to open up sustained views of the Sun's faint surrounding corona...////...