Aditya L1
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It is the first observatory-class space-based solar mission from India.
Major Science Objectives:
- Understand the coronal heating and solar wind acceleration
- Understanding initiation of Coronal Mass Ejection (CME), flares and near earth space weather.
- To understand coupling and dynamics of the solar atmosphere
- To understand solar wind distribution and temperature anisotropy.
Why study sun from space?
- The sun emits radiation/light in nearly all wavelengths along with various energetic particles and magnetic fields.
- The atmosphere of the Earth as well as its magnetic field acts as a protective shield and blocks a number of harmful wavelength radiations including particles and fields.
- As various radiations don’t reach the surface of the Earth, the instruments from the Earth will not be able to detect such radiation and solar studies based on these radiations could not be carried out. However, such studies can be carried out by making observations from outside the Earth atmospheree., from space. Similarly, to understand how the solar wind particles and magnetic field from the Sun travel through the interplanetary space, measurements are to be performed from a point which is far away from the influence of the Earth’s magnetic field.
A Satellite placed in the halo orbit around the Lagrangian point 1 (L1) of the Sun-Earth system has the major advantage of continuously viewing the Sun without any occultation/ eclipses. Therefore, the Aditya-1 mission has now been revised to “Aditya-L1 mission” and will be inserted in a halo orbit around the L1, which is 1.5 million km from the Earth. The satellite carries additional six payloads with enhanced science scope and objectives.
About HALO Orbits: A halo orbit is a, three dimensional orbit near the L1, L2, or L3 Lagrangian point in the three body problem of orbital mechanics. Although the Lagrange point is just a point in empty space, its peculiar characteristics is that it can be orbited.
Understanding Lagrangian Points
- These are position in an orbital configuration of two large bodies where a small object affected only by gravity can maintain a stable position relative to two large bodies. The Lagrange points mark positions where the combined gravitational pull of two large masses provides precisely the centripetal force required to orbit with them.
- The interaction of the forces creates a point of equilibrium where a spacecraft may be “parked” to make observation.
- These points are named after Joseph-Louise Lagrange, an 18th-century mathematician.
- There are five such points, labeled L1 to L5, all in the orbital plane of two large bodies.
- The first three are one the line connecting the two large bodies and the last two, L4 and L5.