February 6 2023: Aditya L-1 is all set to become India's first space mission to observe and study the Sun and solar corona. What are the objectives of the mission? What is "L" in L-1? Explained in Solar mission - ReferencePepper Part 1
Aditya L-1 is all set to become India's first space mission to observe and study the Sun and solar corona. Corona is a luminous envelope of plasma that surrounds the Sun and other celestial bodies.
The mission will be launched by June - July 2023 by the Indian Space Research Organisation (ISRO). This has been confirmed by ISRO Chairman Mr S Somanath himself, and he has also mentioned that the launch window will be closed by August.
Aditya L-1 has a total of seven payloads and the primary payload, or the Visible Emission Line Coronagraph (VELC) has been designed by the Indian Institute of Astrophysics, Bengaluru.
Payload is the object or the entity which is being carried by the launch vehicle.
What are the major Science Objectives of Aditya L-1 mission?
| 1 | To study of Solar upper atmospheric (chromosphere and corona) dynamics. |
The visible surface of the Sun is called Photosphere
Chromosphere (an irregular layer above the photosphere where the temperature rises from 6000°C to about 20,000°C)
The Transition Region (a thin and very irregular layer of the Sun's atmosphere that separates the hot corona from the much cooler chromosphere)
And then the Corona, the outermost, hot shell of the atmosphere.
Beyond the corona is the solar wind, which is actually an outward flow of coronal gas. The sun's magnetic fields rise through the convection zone and erupt through the photosphere into the chromosphere and coron
Credit and Source: NASA/ GODDARD
| 2 | Study of chromospheric and coronal heating, initiation of the coronal mass ejections, and flares. |
Coronal Mass Ejections (CMEs) are large expulsions of plasma and magnetic field from the Sun's corona.
A solar flare is a sudden eruption of brightness from the Sun’s surface. It's not only light and heat but along with it UV radiation, gamma rays and radio waves. And that's not all, a solar flare can also eject massive clouds of electrons, atoms and ions.
| 3 | Physics of solar corona and its heating mechanism. |
Why the quest to study the heating mechanism of the Sun's Corona?
The Sun is hot, and as you move away from the Sun, the temperature should decrease (become cooler than the source of heat) ...correct?
But that is not the case with Corona. Corona, as we mentioned in the article earlier, is the outermost part of the Sun's atmosphere yet 100 times hotter than the Sun itself.
That is one of the mysteries this mission would also try to find an answer to.
| 4 | Development, dynamics and origin of CMEs. |
Coronal Mass Ejections (CMEs) are large expulsions of plasma and magnetic field from the Sun's corona often followed by Solar flares. These blasts carry tons of material out from the Sun at very high speeds of hundreds of kilometers per second. The plasma is released into the solar wind, and can be observed in coronagraph imagery.
Picture source: NASA/ GODDARD
Coronagraph is an instrument that blocks out light emitted by the sun's actual surface so that the corona can be observed.
In picture: Coronagraph at the Wendelstein Observatory
Wendelstein is a 1,838-metre-high (6,030 ft) mountain in the Bavarian Alps in South Germany. On the summit of the Wendelstein there is a weather station belonging to the German Meteorological Office, which is manned around the clock, and an observatory of the Institute for Astronomy and Astrophysics at the Ludwig Maximilian University of Munich.
Source: Wikipedia
We will explain the rest of the objectives in Solar Mission - Part 2 of the ReferencePepper.
Now, back to the main article:
The six other payloads have been developed by ISRO and other scientific institutions. VELC took a total of 15 years from conception to development to completion. The long developmental period is indicative of its complex structure and it is undoubtedly one of the finest collaborations between the IIA and ISRO, as mentioned by Mr Somanath.
For the testing of VELC and its eventual incorporation with the Aditya L-1 spacecraft, it will be taken to the U.R. Rao Satellite Centre in Bengaluru for its integration into the satellite, which will finally be ready to be launched using the PSLV (Polar Satellite Launch Vehicle).
VELC would be able to observe the solar corona continuously and the data collected by the same will answer many questions in the field of solar astronomy.
No other space instrument is powerful enough to collect data as close to the solar disc as VELC can, as it can image as close as 1.05 times the solar radius, along with related imaging, spectroscopy and polarimetry at the same time, simultaneously taking observations at a very high resolution, and that too very frequently.
