At 05:48 CEST on 7 August 2022, the Indian Space Research Organization, the Indian space agency, first launched the new Small Satellite Launch Vehicle (SSLV). After a successful take-off, a problem with the rocket's fourth stage caused the mission to fail.
The rocket was created to launch 500 kg into a low earth orbit with a low price, compared to other vehicles, and with a high cadence.
To meet the requirements, the agency has created a four-stage rocket, three of which are solid propellant and the fourth liquid propellant.
The first stage The first stage of the SSLV, known as SS1, uses an S85 solid fuel engine that produces a maximum thrust of 2496 thanks to 87 tons of fuel. This stage has, on the outside, four fins that control the attitude of the vehicle during the flight in the atmosphere.
The second stage The second bushel, or SS2, uses a solid S7 engine, similar to that used on the PSLV rocket. This engine, thanks to the 7.7 tons of fuel contained in the stage, produces a maximum thrust in vacuum of 234.2 kN.
The third stage SS3 uses a S4 soldio engine and produces 160 kN of thrust in the vacuum burning 4.5 tons of propellant.
The propellant used in the first three stages of the rocket is HTPB, or hydroxyl terminated polybutadiene.
The fourth stage The fourth stage, the one that malfunctioned during the first mission, is called the Velocity Trimming Module and uses storable liquid monomethylhydrazine (MMH) and mixed nitrogen oxides (MON3). This stage has 16 thrusters, 8 of which are used for changing the speed of the stage while the others are used for trim control. Each thruster produces 50 N of thrust.
How did the mission go?
After a successful takeoff from the first launch pad at Satish Dhawan Space Center, the first stage separated 127.5 seconds into the flight. Subsequently, at 161.9 seconds the fairings were released and the second stage separated at 336.9 seconds.
SS3 started at 342.2 and then split at 633.3 seconds.
At T + 642 seconds the VTM fired its thrusters, however only 0.1 seconds of this firing was detected by the Mission Control Center.
After that the separation of the EOS-02 satellite, which was supposed to take place 742 seconds after launch, was not confirmed due to the lack of data.
The failure of the mission was subsequently communicated on ISRO's social channels.
The fourth stage and the payloads probably re-entered the Pacific Ocean in the following minutes.
What was lost?
The mission's main payload was the EOS-02 satellite weighing about 145 kg and was equipped with medium-wavelength and long-wavelength infrared cameras, with a maximum resolution of six meters.
With an expected mission duration of 10 months, the EOS-02 was to be used for Geographic Information Systems (GIS) applications such as cartography, urban and rural management, coastal land use and regulation, and utility mapping.
Also on board was the cubsat AzaadiSAT, built by students from 75 schools across India. This cubesat had to carry out small experiments. On board the small satellite there were no less than 75 payloads weighing 50 grams each.