In a first, India is set to launch a dedicated scientific mission called Aditya-L1 to study the Sun. Indian Institute of Astrophysics (IIA) on Thursday handed over to ISRO, the Visible Line Emission Coronagraph (VELC), the primary payload on board Aditya-L1, which is the mission to study the Sun. The mission is set to be launched by June or July.
ISRO chairman S. Somanath, speaking at the handover ceremony of the Visible Line Emission Coronagraph (VELC) payload on Thursday, said that the Aditya-L1 mission will be launched by June or July as the launch window for the mission would close by August.
The Aditya-L1 mission will be launched by ISRO to the L1 orbit (which is the first Lagrangian point of the Sun-Earth system). L1 orbit allows Aditya-L1 to look at the Sun continuously.
In total Aditya-L1 has seven payloads, of which the primary payload is the Visible Emission Line Coronagraph (VELC), designed and fabricated by the Indian Institute of Astrophysics, Bengaluru.
The other six payloads are being developed by the ISRO and other scientific institutions. “Understanding the effect of the Sun on the Earth and its surroundings has become very important now and Aditya-L1 aims to shed light on this topic. It has taken 15 years for VELC from concept to completion, and this period was needed for a complex system like this. The VELC has been the finest collaboration between the IIA and the ISRO,” said Mr. Somanath.
Following the handover of the VELC payload, the ISRO will now conduct further testing of VELC and its eventual integration with the Aditya-L1 spacecraft.
“This is the main instrument (VELC payload) on board the Aditya-L1 satellite. There are also other instruments which are developed by the ISRO and other institutions. Currently, we are getting ready with the satellite. The payload will be taken to the U.R. Rao Satellite Centre in Bengaluru, where we will integrate it with the Aditya-L1 satellite which will undergo a lot of testing, evaluation, and finally, it will be launched using the PSLV,” Mr. Somanath added.
Raghavendra Prasad, Principal Investigator, VELC payload, said that the payload will be able to observe the corona continuously and the data provided by it is expected to answer many outstanding problems in the field of solar astronomy.
“No other solar coronagraph in space has the ability to image the solar corona as close to the solar disk as VELC can. It can image it as close as 1.05 times the solar radius. It can also do imaging, spectroscopy, and polarimetry at the same time, and can take observations at a very high resolution (level of detail) and many times a second,” Prof. Prasad said.
“Many students tell me that they want to become astrophysicists and institutes like IIA should further enhance their efforts to explain their work to the public,” he said.
IIA Director Prof. Annapurni Subramaniam, who released the official logo of the VELC payload, said “VELC is a team effort and is a major milestone for the institute. The effort has involved close collaboration between IIA, ISRO and many industries across India. We look forward to exciting science results coming from this payload after it is operational.” The space solar mission was initially conceived as Aditya-1 with a 400 kg class satellite carrying one payload (VELC), and was planned to be launched in an 800 km low earth orbit.
Since a satellite placed in a halo orbit around the L1 of the Sun-Earth system has the major advantage of continuously viewing the Sun without any occultation/eclipses, the mission was revised to Aditya-L1, and it would now be inserted in a halo orbit around the L1, which is 1.5 million km from the Earth towards the Sun.
The other six payloads are: Solar Ultraviolet Imaging Telescope, Aditya Solar Wind Particle Experiment, Plasma Analyser Package for Aditya, Solar Low Energy X-ray Spectrometer, High Energy L1 Orbiting X-ray Spectrometer, and Magnetometer The scientific studies by the satellite will enhance our current understanding of the Solar Corona and also provide vital data for space weather studies”, ISRO officials said.
