Going Again: ISRO’s New Rocket, Small Satellite Launch Vehicle, Set For Second Launch After Amends

After the first space mission involving India’s new launcher, the Small Satellite Launch Vehicle (SSLV), came up short in August last year, the Indian Space Research Organisation (ISRO) is attempting a more successful re-do on Friday, 10 February.

The SSLV-D2/EOS-07 mission will take off at 9.18 am from the first launch pad at Satish Dhawan Space Centre-Sriharikota Range (SDSC-SHAR), off the coast of Andhra Pradesh.

Flying for a total of 15 minutes, the launch vehicle will place the Earth-observation Satellite EOS-07, as well as Janus 1 and AzaadiSAT-2 satellites, into a 450-kilometre (km) circular orbit.

Injection of the three satellites into their planned orbit and demonstration of the in-flight performance of SSLV systems are the mission objectives. (More details later in the article)

The SSLV is capable of launching mini, micro, and nano satellites — 10 kg to 500 kg mass — into a 500-km planar orbit on an on-demand basis.

It’s a three-stage vehicle. Whereas solid fuel fires the three stages, satellite insertion into the intended orbit is achieved through a liquid propulsion-based velocity trimming module as the terminal stage.

First Flight

In the maiden SSLV mission last year, the launcher carried the 135-kg EOS-02 and 7.3-kg nano satellite AzaadiSAT, the latter developed by the student team of the startup Space Kidz India.

The EOS-02 was an experimental optical remote sensing satellite with a high spatial resolution for application in areas like agriculture, forestry, geology, and hydrology.

AzaadiSAT, a tribute to India’s celebration of ‘Azaadi ka Amrit Mahotsav’, was a cubesat comprising 75 different payloads each weighing around 50 g, built by girl students from across India’s rural regions.

The rocket took off on schedule, at 9.18 am on 7 August, and all the stages were in progress before trouble came knocking.

“Data loss is observed during the terminal stage. It is being analysed. Will be updated soon,” ISRO said in a Twitter update.

Later, in a video statement, ISRO chairman S Somanath said, “The 356 km circular orbit was our intended orbit, but it (the launch vehicle) could place the satellite in an orbit of 356 x 76 km.”

“The satellites have already come down from that orbit and they are no longer usable,” he added.

The satellites were injected into a highly elliptical unstable orbit before they crashed into the sea soon after.

The mission could not be achieved due to an anomaly during the second stage separation, triggering a “mission salvage mode.”

Still, the ISRO chief was “very happy” at the time with all the various technologies that were put to work and proven for the first time as part of the SSLV mission.

In Search of Success

SSLV’s second developmental flight is launching Friday (10 February).

ISRO’s EOS-07 satellite is flying on it. New experiments on the 156.3-kg satellite include the millimetre-wave humidity sounder and spectrum monitoring payload. The satellite will have a mission life of about one year.

The co-passenger satellites are Janus-1 and AzaadiSAT-2. 

Janus-1 is a 10.2-kg satellite built in a record time of just 10 months with payload providers from seven countries. It’s a technology demonstrator, smart satellite mission based on the Antaris software platform.

Antaris is the world’s first software platform that dramatically simplifies the design, simulation, and operation of satellites. The company Antaris Inc is based in Los Altos, California.

The 8.7-kg AzaadiSAT-2 is a combined effort of about 750 girl students across India guided by Chennai-based Space Kidz India.

The mission aims to demonstrate LoRa and amateur radio communication capabilities and measure radiation levels in space, among other things.

Why the SSLV?

There’s a handsome demand among developing countries, private corporations, and educational institutions for the launch of small satellites, weighing up to 500 kg, into 500 km low-Earth orbit (LEO).

The SSLV will be used to deploy small satellites — from 10 kg to 500 kg — in LEO.

Larger launch vehicles, like the polar satellite launch vehicle (PSLV), were not able to provide the kind of cost-effective and flexible launch solutions required by smaller players.

The SSLV will offer low turnaround time, flexibility in accommodating multiple satellites, launch-on-demand feasibility, and minimal launch infrastructure requirements.

The SSLV is slated to become the next ISRO workhorse, playing a key role in the commercial small satellite launch services.