PSLV-XL | Proba-3

Proba-3 (Project for On-Board Autonomy 3) is the first close formation flying mission for the European Space Agency (ESA). It consists of two independent, three-axis stabilised spacecraft flying 150 meters from one another with the ability to accurately control the attitude and separation of the two craft. Such formation flying will be maintained for 6 hours, creating ″artificial solar eclipse″ for the satellite below. The spacecraft pair will fly a highly elliptical orbit divided between periods of accurate formation flying around apogee, when payload operations will be possible, and periods of free flight.

PSLV-XL is the upgraded version of Polar Satellite Launch Vehicle in its standard configuration boosted by more powerful, stretched strap-on boosters with 12 tonne propellant load. Weighing 320t at lift-off, the vehicle uses larger strap-on motors (PSOM-XL or S12) to achieve higher payload capability. On 29 December 2005, ISRO successfully tested the improved version of strap-on booster for the PSLV. The first use of PSLV-XL was the launch of Chandrayaan-1 by PSLV C11. The payload capability for this variant is 1,800 kg to SSO.

The Indian Space Research Organisation (ISRO) is the space agency of the Government of India headquartered in the city of Bangalore. Its vision is to "harness space technology for national development while pursuing space science research and planetary exploration."