Launching Aditya-L1 satellite for solar study underway
Jun 09, 2016
Scientific mission of launching Aditya-L1 satellite for solar studies is underway by ISRO.
About Aditya Mission:
- The Aditya-1 mission was conceived as a 400kg class satellite carrying one payload, the Visible Emission Line Coronagraph (VELC) and was planned to launch in a 800 km low earth orbit.
- 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 occultatiowx w cxn 4n/ 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.
Aditya-1 was meant to observe only the solar corona. The outer layers of the Sun, extending to thousands of km above the disc (photosphere) is termed as the corona. It has a temperature of more than a million degree Kelvin which is much higher than the solar disc temperature of around 6000K. How the corona gets heated to such high temperatures is still an unanswered question in solar physics.
What’s new in Aditya L-1
- Aditya-L1 with additional experiments can now provide observations of Sun's Photosphere (soft and hard X-ray), Chromosphere (UV) and corona (Visible and NIR).
- In addition, particle payloads will study the particle flux emanating from the Sun and reaching the L1 orbit, and the magnetometer payload will measure the variation in magnetic field strength at the halo orbit around L1. These payloads have to be placed outside the interference from the Earth’s magnetic field and could not have been useful in the low earth orbit.
- Visible Emission Line Coronagraph (VELC): To study the diagnostic parameters of solar corona and dynamics and origin of Coronal Mass Ejections (3 visible and 1 Infra-Red channels); magnetic field measurement of solar corona down to tens of Gauss –Indian Institute of Astrophysics (IIA)
- Solar Ultraviolet Imaging Telescope (SUIT): To image the spatially resolved Solar Photosphere and Chromosphere in near Ultraviolet (200-400 nm) and measure solar irradiance variations - Inter-University Centre for Astronomy & Astrophysics (IUCAA)
- Aditya Solar wind Particle Experiment (ASPEX) : To study the variation of solar wind properties as well as its distribution and spectral characteristics – Physical Research Laboratory (PRL)
- Plasma Analyser Package for Aditya (PAPA) : To understand the composition of solar wind and its energy distribution – Space Physics Laboratory (SPL), VSSC
- Solar Low Energy X-ray Spectrometer (SoLEXS) : To monitor the X-ray flares for studying the heating mechanism of the solar corona – ISRO Satellite Centre (ISAC)
- High Energy L1 Orbiting X-ray Spectrometer (HEL1OS): To observe the dynamic events in the solar corona and provide an estimate of the energy used to accelerate the particles during the eruptive events - ISRO Satellite Centre (ISAC)and Udaipur Solar Observatory (USO), PRL
Challenge of Aditya L-1
- To build a few ultra-sensitive instruments to accurately measure minute details about the Sun.
- Another bigger challenge is to create an all-aluminium 20-metre-high magnetic test facility near Bengaluru to specially assemble and test the spacecraft and instruments in a magnetically clean manner with “not one electric material, not even a car, being nearby”.
- Financial constraint: A satellite and a launcher each cost around Rs. 200 crore. Can the nation afford a second spacecraft?
- The prototype that qualifies all tests could be sent into L5 as it will be as good as the final one. It would still need another PSLV launcher.
Five locations around a planet’s orbit where the gravitational forces and the orbital motion of the spacecraft, Sun and planet interact to create a stable location from which to make observations. These points are known as Lagrangian or ‘L’ points, after the 18th century Italian astronomer and mathematician Joseph-Louis Lagrange (born Giuseppe Luigi Lagrancia).