SSLV-D1: Microsat 2A And AzaadiSAT No Longer Usable As They Failed To Reach Intended Orbit, ISRO Says

ISRO's Small Satellite Launch Vehicle (SSLV) has failed to place the satellites Microsat 2A and AzaadiSAT into the intended circular orbit. As a result, the satellites are no longer usable.

SSLV-D1, the maiden mission of India's smallest launch vehicle (left) that took flight on Sunday, August 7, was supposed to place Microsat 2A (right) and AzaadiSAT into a 356-kilometre circular orbit. However, the satellites have instead been placed into an elliptical orbit.

Source : ISRO

The Indian Space Research Organisation's (ISRO's) Small Satellite Launch Vehicle (SSLV) has failed to place the satellites Microsat 2A and AzaadiSAT into the intended circular orbit. As a result, the satellites are no longer usable, ISRO said in a mission update. 

SSLV-D1, the maiden mission of India's smallest launch vehicle that took flight on Sunday, August 7, was supposed to place the two satellites into a 356-kilometre circular orbit. However, the satellites have instead been placed into a 356 km × 76 km elliptical orbit. ISRO said that the issue is reasonably identified, and that the "failure of a logic to identify a sensor failure and go for a salvage action caused the deviation".

(1/2) SSLV-D1/EOS-02 Mission update: SSLV-D1 placed the satellites into 356 km x 76 km elliptical orbit instead of 356 km circular orbit. Satellites are no longer usable. Issue is reasonably identified. Failure of a logic to identify a sensor failure and go for a salvage action

— ISRO (@isro) August 7, 2022

The space agency also wrote that a committee would analyse the situation and make recommendations.

ISRO said that the space agency will soon launch SSLV-D2, the second flight of India's latest launch vehicle. 

"With the implementation of the recommendations, ISRO will come back soon with SSLV-D2," ISRO stated.

The SSLV-D1 mission took off from First Launch Pad, Satish Dhawan Space Centre in Sriharikota, Andhra Pradesh, at 9:18 am IST. The primary payload of SSLV was Microsat 2A, an Earth Observation Satellite also known as EOS-02. AzaadiSAT, an eight-kilogram CubeSat built by 750 girl students from 75 schools across India, was also launched into space as a co-passenger on India's latest launch vehicle.

SSLV is a three-stage launch vehicle configured with three solid propulsion stages and a terminal stage. A solid propulsion rocket stage uses solid propellants as the fuel. The terminal stage is a liquid propulsion-based Velocity Trimming Module (VTM). 

The first, second, and third stages weigh 87 tonnes, 7.7 tonnes, and 4.5 tonnes, respectively.

According to ISRO, SSLV has a diameter of 2.1 metres and a length of 34 metres. The liftoff mass of the launch vehicle is approximately 120 tonnes.