ISRO successfully launches SSLV’s second developmental flight with three satellites from Sriharikota

SSLV-D2 took off precisely at 09:18 hours IST on February 10, 2023 from the first launch pad at the Satish Dhawan Space Centre-SHAR, Sriharikota.
| Photo Credit: R. RAGU

The Indian Space Research Organisation (ISRO) successfully launched its second developmental flight of a Small Satellite Launch Vehicle — SSLV-D2 — and placed three satellites in its precise orbit on February 10 morning.

The three satellites are ISRO’s Earth Observation Satellite – EOS 07, U.S.-based firm Antaris’ Janus-1 and Chennai-based space start-up SpaceKidz’s AzaadiSAT-2. 

SSLV-D2 lifted off from the first launch pad at Satish Dhawan Space Centre-SHAR, Sriharikota at 9:18 a.m. This is the first satellite launch in 2023.

“The SSLV-D2-EOS-07 mission is successfully accomplished,” ISRO mentioned on its Twitter handle, a few minutes after the vehicle took off. ISRO in a statement said: “The vehicle injected satellites into close to 450 km circular orbit at an inclination of 37.2 degrees. The tracking network took control of EOS-07 satellite. Deployment of the solar panels and the generation of power is confirmed.”

ISRO Chairman S. Somanath said, “In its second attempt SSLV-D2 has placed the EOS-07 satellite in its intended orbit very accurately. Two more satellites -Janus-1 and AzaadiSAT-2 were also placed in the required orbit.”

The Chairman further said: “SSLV had its maiden flight SSLV-D1 and we had a narrow miss of placing the satellite in the orbit because of a shortfall in velocity. I’m happy to report that we have analysed the problems faced in SSLV D1 – identified the corrective actions and implemented it. We went through lot of studies to ensure that the vehicle will become success this time,” he added. 

“And I’m happy this has been executed in reality. The orbit achieved by the vehicle today is exceedingly good,” Mr. Somanath said.

Noting that this journey began in 2018, S.S. Vinod, Mission Director of SSLV, said, “We had the maiden flight in August 2022 and we could not place the satellite in the intended orbit. Post that detailed analysis with a number of teams was carried out and we were able to pinpoint the problem in the system. We overcame that.”

He added, “And in a period of five months we have come back. And we will be coming back soon with the next launch of SSLV.”

It may be recalled that the first developmental flight of SSLV lifted off from Satish Dhawan Space Centre on August 7, 2022, and ended up to be a partial failure, as the rocket failed to inject its satellite payload in their intended orbits.

According to ISRO, the spacecraft was injected into a highly elliptical unstable orbit due to a shortfall in velocity, leading to their decay and deorbiting immediately, in spite of the normal performance of all solid propulsion stages. 

Subsequent detailed analysis of the flight events and observations ranging from the countdown, lift-off, propulsion performance, stage separations and satellite injection revealed that there was a vibration disturbance for a short duration on the Equipment Bay (EB) deck during the second stage (SS2) separation. This affected the Inertial Navigation System (INS), resulting in declaring the sensors faulty by the logic in Fault Detection and Isolation (FDI) software.

Also Read | Space to learn: On the failure of ISRO’s maiden small satellite launch vehicle mission

About SSLV-D2

EOS-07 is a 156.3 kg satellite designed, developed and realized by ISRO. The mission objective of EOS-07 is to design and develop payload instruments compatible with microsatellite bus and new technologies, which are required for future operational satellites. Moreover, it will also design and develop a microsatellite accommodating new technology payloads in a quick turn-around time. 

New experiments include mm-Wave Humidity Sounder and Spectrum Monitoring Payload. Weighing around 10.2 kg, Janus-1 is a technology demonstrator, smart satellite mission based on the Antaris software platform. An 8.7 kg satellite AzaadiSAT-2 is a combined effort of about 750 girl students across India guided by Space Kidz India, Chennai.

According to details provided by ISRO, SSLV caters to the launch of up to 500 kg satellites to Low Earth Orbits on a “launch-on-demand” basis. It provides low-cost access to space, offers low turn-around time and flexibility in accommodating multiple satellites, and demands minimal launch infrastructure. It is configured with three solid propulsion stages and a velocity terminal module. It is a 34 m tall, 2 m diameter vehicle having a lift-off mass of 120 tonnes.