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  • Writer's pictureRANGAN PAL

Largest payload of Aditya-L1 spacecraft handed over to ISRO

Updated: Feb 3, 2023

The Indian Space Research Organisation (ISRO) Thursday received the largest payload — Visible Line Emission Coronagraph (VLEC) — which would fly on Aditya L1, India’s first dedicated scientific mission to study the Sun by the Indian Institute of Astrophysics (IIA) at a function in Bengaluru.

IIA has built the VELC at its Centre for Research and Education in Science and Technology (CREST) campus in Hoskote. ISRO will now conduct further testing of VLEC and its eventual integration with the Aditya-L1 spacecraft. Aditya L-1 is a planned coronagraphy spacecraft. VLEC is designed to perform tasks like imaging and spectroscopy to unravel the secrets of the solar corona which is the outermost layer of the Sun and is one of the most difficult attributes of the star to be studied.

Secretary, Department of Space and Chairman, ISRO, S Somnath said, “VLEC is a primary instrument. Aditya L1 will have a set of instruments which will play an important role in observing the sun. After AstroSat, this is a very important scientific mission which ISRO has undertaken. The journey for building this complex satellite has been a long one. People in this domain know the challenges in building an instrument like VLEC. Understanding the effect of the Sun on 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 VLEC from concept to completion, and this period was needed for a complex system like this. The VLEC has been the finest collaboration between IIA and ISRO.”

He also said the launch of Aditya-L1 is expected to be around June or July this year.

“ISRO aims to play an important role in future science experiments in space and an ecosystem needs to be created for this, including a roadmap for the next few decades. ISRO encourages Indian scientists to come up with new and novel ideas for future space science instruments that have not been done before by others in the world. 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,” Somnath added.

Earlier, this mission was conceived as Aditya-1 with a 400 kg class satellite carrying one payload, the VLEC and was planned to be launched in an 800 km low earth orbit.

“Since a satellite placed in the halo orbit around the first Lagrangian point (L1) of the Sun-Earth system has the major advantage of continuously viewing the Sun without any occultation/eclipses, the Aditya-1 mission has now been revised to Aditya-L1 mission. The satellite will be inserted in a halo orbit around the L1, which is 1.5 million km from the Earth towards the Sun,” IIA said.

Langrangian points are positions in space where objects sent there tend to stay put. L1 is located 1.5 million kilometers from Earth.

The satellite carries additional six payloads -Solar Ultraviolet Imaging Telescope (SUIT), Aditya Solar Wind Particle Experiment (ASPEX), Plasma Analyser Package for Aditya (PAPA), Solar Low Energy X-ray Spectrometer (SoLEXS), High Energy L1 Orbiting X-ray Spectrometer (HEL1OS) and Magnetometer.

Professor Annapurni Subramaniam, Director of Indian Institute of Astrophysics, congratulated the VLEC team and said, “VLEC 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 Principal Investigator of the VLEC payload, Professor Raghavendra Prasad said, “No other solar coronagraph in space has the ability to image the solar corona as close to the solar disk as VLEC 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”. This capability will revolutionise solar astronomy around the world and the data is expected to answer many outstanding problems in the field.”

Nigar Shaji of ISRO, the Programme Director of Aditya-L1, said, “This is one of the best days for the Aditya-L1 team and for myself.”

The VLEC team of IIA flagged off the truck housing the VLEC. The payload has been placed in a container and the team have been continuously monitoring its health using sensors placed within. The payload will be taken to URSC ISRO on Friday morning.


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