Note4Students

From UPSC perspective, the following things are important :

Prelims level: Aditya L1 mission

Mains level: Read the attached story

aditya

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.

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.

(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.

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.

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.