India gets its own mini space lab
The Indian Space Research Organisation has added another feather in its cap with the successful launch of EMISAT and 28 international customer satellites
This is no joke, but it was on April 1, 2019, that India and the world got its first ‘mini space laboratory’! It was the 47th mission of India’s workhorse rocket, the Polar Satellite Launch Vehicle(PSLV), and it was one of the most innovative and novel missions which also gave India a floating laboratory in space at 485 km orbit. This was also a first-of-a-kind three-in-one mission where the Indian Space Research Organisation (ISRO) was optimising the use of a single rocket to garner three different orbits.
The 320 tonne, nearly 44-metre-tall rocket carried as its main passenger, the 436 kg EMIsat, a satellite intended for electromagnetic spectrum measurement and essentially made for the Defence Research and Development Organisation. Alongside, the launch also lofted 28 small satellites from USA, Switzerland, Lithuania and Spain. These include 20 Flock-4A satellites and four Lemur satellites from Planet Labs in California. The satellites were placed in three different orbits. Hence, at the cost of a single launch, triple benefits were reaped.
Speaking after the successful mission, ISRO Chairman Dr K Sivan congratulated the launch vehicle and satellite teams involved in the mission, saying, “Today’s PSLV mission was unique in several ways. It was a four strap-on new variant, the vehicle achieved three different orbits and for the first time, the PS4 stage is powered by solar panels.” This was a long three-hour mission and at the end of the marathon mission, the PSLV placed in orbit ‘India’s mini floating laboratory’ in near zero gravity. To do this, ISRO converted the last stage of the rocket, or PS4, into a full-fledged orbital platform. The last stage of the rocket usually turns into space debris after the launch but ISRO decided to extend its life by a few weeks and made it into a spaceborne lab.
The PS4, orbiting at 485 km orbit, has been laced with solar panels, radio communication equipment and three payloads or mini satellites have been plugged into the spent rocket stage. The payloads carried by PS4 are the automatic identification system from ISRO, Automatic Packet Repeating System from AMSAT, India and an Advanced Retarding Potential Analyzer for ionospheric studies from the Indian Institute of Space Science and Technology.
These are all experimental payloads where researchers have been given a free ride into space to test futuristic technologies. Sivan said the PSLV C-45, mission was special in the sense, for the first time PSLV had a three orbit mission in a single flight. Initially the principle satellite was launched in the 784 km, subsequently the PS4 functioned two times to reduce the orbit to 504 km, there the PSLV launched the 28 customer satellite subsequently the PSLV was again fired up and the PS4 was burnt two times to reduce the orbit to 485 km, here the PS4 now functions as an orbital platform.
Not many countries have tried to re-use spent rocket stages. Sivan points out. According to him, “This will give new opportunities to start-ups and university researchers to make optimum space worthy payloads. Moreover users need not struggle to make full satellites all they need is to make their space grade experiment rest is really a play and plug job to be undertaken by ISRO. Sivan adds, “This now opens a new era for low cost but effective space research, by utilising India’s innovative mini space lab.