The Indian Space Research Organisation (ISRO) is planning to launch the Aditya-L1 mission by June or July this year.
What is Aditya-L1 Mission?
- ISRO categorizes Aditya L1 as a 400 kg-class satellite that will be launched using the Polar Satellite Launch Vehicle (PSLV) in XL configuration.
- It will observe the Sun from a close distance, and try to obtain information about its atmosphere and magnetic field.
- The space-based observatory will have seven payloads (instruments) on board to study the Sun’s corona, solar emissions, solar winds and flares, and Coronal Mass Ejections (CMEs), and will carry out round-the-clock imaging of the Sun.
L1: Behind the name
- L1 refers to Lagrangian/Lagrange Point 1, one of five points in the orbital plane of the Earth-Sun system.
- Lagrange Points, named after Italian-French mathematician Josephy-Louis Lagrange, are positions in space where the gravitational forces of a two-body system (like the Sun and the Earth) produce enhanced regions of attraction and repulsion.
- The L1 point is about 1.5 million km from Earth, or about one-hundredth of the way to the Sun.
Major payloads
- 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 satellite carries additional six payloads-
- SUIT, the solar ultraviolet imaging telescope
- ASPEX (Aditya Solar Wind Particle Experiment),
- PAPA (Plasma Analyser Package for Aditya),
- SoLEXS (Solar Low Energy X-ray Spectrometer),
- HEL1OS (High Energy L1 Orbiting X-ray spectrometer) and
- Magnetometer — with enhanced science scope and objectives possible by extensive remote and in-situ observation of the sun.
Why is studying the Sun important?
(1) To understand space weather
- To learn about and track Earth-directed storms, and to predict their impact, continuous solar observations are needed.
- Every storm that emerges from the Sun and heads towards Earth passes through L1, and a satellite placed in the halo orbit around L1 of the Sun-Earth system has the major advantage of continuously viewing the Sun without any occultation/eclipses.
(2) Observing corona
- The VELC 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.
Why are solar missions challenging?
- Distance: What makes a solar mission challenging is the distance of the Sun from Earth (about 149 million km on average, compared to the only 3.84 lakh km to the Moon).
- Heat: More importantly the super-hot temperatures and radiations in the solar atmosphere make it difficult to study.
Major missions to Sun till now
- NASA’s Parker Solar Probe has already gone far closer — but it will be looking away from the Sun.
- The earlier Helios 2 solar probe, a joint venture between NASA and space agency of erstwhile West Germany, went within 43 million km of the Sun’s surface in 1976.
