At 10 am this (Monday) morning, a PSLV-XL rocket lifted off with India’s first space-borne astronomical observatory from ISRO’s Satish Dhawan Space Centre at Sriharikota. The observatory, titled ASTROSAT, is set to be placed in a low-Earth orbit at an altitude of 650.17 km by the rocket after its fourth-stage ignition is cut off 21 minutes and 56 seconds after launch. When that happens, India will become the first developing nation to have launched an astronomical satellite.
The launch – the 30th successful one in a row for the PSLV – will also place one Canadian and one Indonesian satellite in orbit, as well as four American nano-satellites, a first. The time of launch coincides with Prime Minister Narendra Modi’s visit to Silicon Valley and on the same day as a planned visit to President Barack Obama. As The Guardian noted, India’s Mars Orbiter Mission entered orbit around Mars just days before Modi’s visit to the US in September 2014.
The five instruments and one passive monitor on board ASTROSAT will all have switched on by December 13, 2015, 45 days from when ASTROSAT enters orbit. The switch-on sequence goes like:
- Charged Particle Monitor – September 29
- Scanning Sky Monitor – October 6
- Cadmium-Zinc-Telluride Imager – October 6
- Large Area X-ray Proportional Counter – October 20
- Ultraviolet Imaging Telescope – December 10
- Soft X-ray Telescope – December 13
By late September 2016, ISRO has said it will start allowing third parties to buy observation time on the instruments, although that will be available to international applicants only by the third year of operations. The proposals will be processed via the ASTROSAT Proposal Processing System on the Indian Space Science Data Centre website.
ASTROSAT has been built to last five years so ISRO is not planning for costly maintenance runs in the future. Its instruments will study sources of high-energy UV and X-radiation in the cosmos, typically objects like supernovae, neutron stars and black holes, with a noted ability to make observations on both wavelengths simultaneously. In general, they will be sensitive to particulate radiation with energies ranging from 0.1 keV to 100 keV.