ISRO’s PSLV-C59 Rocket Takes Off With ESA’s Proba-3: A Stellar Solar Eclipse Experiment!

In a remarkable achievement, the Indian Space Research Organisation (ISRO) successfully launched the European Space Agency's (ESA) Proba-3 mission aboard the PSLV-C59 rocket on Thursday.

The mission lifted off from the first launch pad at the Satish Dhawan Space Centre in Sriharikota, marking ISRO's 61st successful launch.

Photo Credit: PTI

Initially scheduled for Wednesday, the launch was postponed due to a propulsion system issue in the satellite. However, the PSLV rocket successfully placed the Proba-3 satellites in the desired orbit just over 18 minutes after liftoff.

The Proba-3 mission, the latest addition to ESA's series of in-orbit demonstration missions, consists of two spacecraft. These will separate once in orbit to perform highly precise formation flying with millimeter-level accuracy - the distance between them will be about the thickness of an average fingernail.

The primary objective of Proba-3 is to simulate a solar eclipse in space, a task that will enable scientists to study the Sun's faint corona, which is typically difficult to observe.

A Solar Eclipse in Space

The two satellites in the Proba-3 mission, named the "Occulter" and the "Coronagraph," will work in tandem to mimic a total solar eclipse. The Occulter spacecraft will cast a precisely controlled shadow onto the Coronagraph spacecraft, blocking out the Sun's fiery disc. This will allow the Coronagraph to capture high-resolution images of the solar corona, the outermost part of the Sun's atmosphere. The Sun's corona is about a million times fainter than the Sun itself, making it challenging to observe without such an eclipse.

The Proba-3 mission will provide unprecedented access to the solar corona, observing it from just 1.1 solar radii - closer than any previous Earth-based or space-based instrument. Unlike natural solar eclipses, which occur only once every 18 months and last a few minutes, Proba-3 will be able to create artificial solar eclipses on demand. The satellites will remain in orbit for 19 hours and 36 minutes, during which they will provide six hours of continuous observation of the solar corona.

Advanced Formation Flying and Space Experiments

Beyond the solar eclipse experiment, Proba-3 will conduct a range of formation flying experiments. These include rendezvous, adjusting the distance between the spacecraft, and joint retargeting. The goal is to achieve performance similar to a single virtual spacecraft, spanning 150 meters across. This innovative method of operating multiple spacecraft in coordinated flight could be pivotal for future space missions that require sharing instruments between platforms.

Radhakrishnan D, the Chairman and Managing Director of NewSpace India Limited (NSIL), which implemented the commercial mission, expressed his delight in the success of the launch. He highlighted that this is the first time a PSLV rocket has placed a satellite in such a highly elliptical orbit, with an apogee of nearly 60,500 km, further demonstrating the versatility and reliability of the PSLV.

The Proba-3 mission opens up new possibilities for solar research, giving scientists the ability to study the Sun's atmosphere with unprecedented detail and over an extended period. It marks a significant milestone in space exploration, particularly in the field of solar science and space instrumentation.