Why in the News?

The Indian Space Research Organisation (ISRO) is set to launch its spacecraft Aditya-L1 to study the Sun, on September 2,2023.

What is the Aditya-L1 mission?

1. 1. 1. The Polar Satellite Launch Vehicle (PSLV) will carry the 1,475-kg spacecraft to an elliptical orbit around the Earth.
      2. The spacecraft will travel 1.5 million km from the Earth to the Lagrange 1 or L1 point between the Earth and the Sun in a period of 4 months.
      3. The distance travelled will be nearly four times as that of the Chandrayaan missions, but just 1% of the 150 million km between the Earth and the Sun.
      4. The spacecraft will carry 7 scientific payloads, which will be more than two times lighter than the one to the Moon.
      5. The orbit as well as the velocity of the spacecraft around the Earth will be increased progressively till it is slingshot towards the Sun.
      6. The spacecraft will then be inserted into a halo orbit around the L1 point and collects the data for 5 years

What is the L1 point?

1. There are five Lagrange points, L1 to L5, between any two celestial bodies.

2. These points can act as parking spots in space where the gravitational pull of the celestial objects equals the centripetal force required to keep a satellite in orbit. 
3. Thus, satellites placed at Lagrange points do not need to expend a lot of fuel to remain in position.
4. Lagrange 1 places the spacecraft at a point beyond the Moon between the Earth and the Sun and hence, an unobstructed view of the Sun even during phenomena like an eclipse can be viewed.
5. The payloads will be able to look directly at the Sun i.e., look directly into the source of coronal mass ejection.

What are the science objectives of Aditya-L1?

1. To obtain a deeper understanding of our closest star and how its radiation, heat, flow of particles, and magnetic fields affects the earth.
2. To study the upper atmospheric layers of the Sun called chromosphere and corona and the expulsion of plasma and magnetic fields called coronal mass ejection (CME). 
3. To study the drivers of the space weather.
4. To find reasons for a million degree C temperature of corona of the sun compared to its surface temperature of about 5,500-degree C.
5. To understand the reasons behind acceleration of particles on the Sun, which leads to solar winds.

Payloads of Aditya L1 mission:

1. Visible Emission Line Coronagraph (VLEC)- the main payload
   1. Designed by the Indian Institute of Astrophysics
   2. To study the solar corona from the lowermost part upwards.
   3. It can image the solar corona down to 1.05 times the solar radius, the closest any such payload has imaged.
2. The Solar Ultraviolet Imaging Telescope (SUIT)
   1. It will capture the UV image of the solar photosphere and chromosphere.
   2. It will help study the variation in light energy emitted.
3. The Solar Low Energy X-ray Spectrometer (SoLEXS) 
4. High Energy L1 Orbiting X-ray Spectrometer (HEL1OS) to study X-ray flares.
5. The Aditya Solar Wind Particle Experiment (ASPEX)
6.  Plasma Analyser Package for Aditya (PAPA) to study the solar wind and energetic ions.

Source URL: ISRO’s Aditya-L1 to be launched on September 2: With feet on the Moon, the space agency eyes the Sun