India is preparing to launch the European Space Agency's (ESA) Proba-3 mission in early December from the Sriharikota spaceport, as announced by Science and Technology Minister Jitendra Singh. The two satellites involved in the Proba-3 mission, which aims to study the Sun, launched in Sriharikota on Tuesday for integration with ISRO's Polar Satellite Launch Vehicle (PSLV). The minister said, "The Proba-3 mission of the European Space Agency will be launched by a PSLV rocket from Sriharikota in the first week of December," during the Indian Space Conclave organized by the Indian Space Association. The launch is anticipated to take place on December 4.
Both Proba-3 spacecraft will be deployed simultaneously by the PSLV-XL launcher into a highly elliptical orbit, reaching an altitude of 60,000 km from Earth before descending to just 600 km. This elevated orbit is essential for the spacecraft's planned active formation flying, which will occur for about six hours at maximum altitude. In this position, the effects of Earth's gravitational pull will be reduced, minimizing the propellant needed for position adjustments.
The Proba-3 satellites will provide continuous observations of the Sun's faint outer atmosphere, or corona, which has only been glimpsed during brief solar eclipses from Earth. For successful operation, the shadow between the two spacecraft must be maintained in a precise location, requiring them to fly in formation with an accuracy of just one millimeter—about the thickness of a typical fingernail.
This mission marks the first time an ESA project will be launched from India since the original Proba-1 Earth-observing mission in 2001.