ADITYA L1
Aditya-L1 is India’s first space-based observatory-class solar mission to investigate the Sun. The spacecraft will be positioned in a halo orbit around the Sun-Earth system’s Lagrange point 1 (L1), approximately 1.5 million kilometers from Earth. A satellite in a halo orbit around the L1 point has the considerable benefit of being able to see the Sun constantly without occultation/eclipse. This will be a significant advantage for continually viewing solar events.
The Advisory Committee for Space Research conceptualized Aditya in January 2008. It was originally planned as a modest 400 kg (880 lb.) LEO (800 km) satellite equipped with a coronagraph to investigate the solar corona. For the fiscal year 2016–2017, an experimental budget of 3 Crore INR was set aside. The mission’s scope has now been increased, and it is currently scheduled to be a complete solar and space environment observatory to be deployed near the Lagrange point L1; hence, it has been renamed “Aditya-L1.” The mission has a budget of 378.53 crore, excluding launch expenses, as of July 2019.
Lagrange Points
The Lagrange Points are the places in space where a small object prefers to stay if placed in a two-body gravitational system. The spacecraft can employ these places in space for a two-body system, such as the Sun and Earth, to stay in these positions while using less fuel. Technically, the gravitational attraction of the two huge things equals the centripetal force required for something small to move with them at the Lagrange point. There are five Lagrange points for two-body gravitational systems labeled L1, L2, L3, L4, and L5. L1 is located between the Sun and Earth lines. L1’s distance from Earth is around a percentage of the Earth-Sun distance.
Payloads that Aditya L1 will carry
The spacecraft will carry seven payloads using electromagnetic and particle detectors to investigate the photosphere, chromosphere, and the Sun’s outermost layers (the corona). Four payloads will directly observe the Sun from the extraordinary vantage point of L1. In comparison, the remaining three payloads will conduct in-situ research of particles and fields at the Lagrange point L1.
The Aditya L1 payload suite is expected to provide the most critical information to understand the problems of coronal heating, Coronal Mass Ejection, pre-flare and flare activities, and their characteristics, space weather dynamics, particle propagation, fields in the interplanetary medium, and so on. The payload will be
1. Visible Emission Line Coronagraph(VELC).
2. Solar Ultraviolet Imaging Telescope (SUIT).
3. Solar Low Energy X-ray Spectrometer (SoLEXS).
4. High Energy L1 Orbiting X-ray Spectrometer(HEL1OS).
5. Aditya Solar Wind Particle Experiment(ASPEX).
6. Plasma Analyzer Package For Aditya (PAPA).
7. Advanced Tri-axial High-Resolution Digital Magnetometers.
Missions of Aditya L1
The key scientific goals of Aditya-L1’s mission are as follows:
• Research into the dynamics of the Sun’s upper atmosphere (chromosphere and corona).
• Investigation of the chromosphere and coronal heating, physics of partly ionized plasma, coronal mass ejections, and flares.
• Study particle dynamics from the Sun by observing the in-situ particle and plasma environment.
• Solar corona physics and heating mechanism.
• Coronal and coronal loop plasma diagnostics: temperature, velocity, and density.
• The evolution, behavior, and genesis of CMEs.
• Recognize the processes at various levels (chromosphere, base, and extended corona) and finally lead to solar eruptive events.
• Magnetic field topology and observations in the solar corona.
• Space weather drivers (origin, composition, and solar wind dynamics).
- The first spatially resolved solar disc.
Specialty of Aditya L1
• First-time spatially resolved solar disc in the near UV band.
• CME dynamics close to the solar disc (from a 1.05 solar radius) offering.
• Information on the acceleration regime of the CME, which is not consistently seen.
• Onboard intelligence to identify CMEs and solar flares.
• Flares for optimized observations and data volume.
• Directional and energetic anisotropy of solar wind utilization.
• Observations in several directions.
