SSLV-D2: ISRO Launches Second Development Flight Of Its Smallest Rocket With Three Payloads

SSLV-D2: ISRO launched the second developmental flight of its smallest launch vehicle on February 10, 2023, from Satish Dhawan Space Centre, Sriharikota. The rocket is carrying three payloads to space

SSLV-D2: The Indian Space Research Organisation (ISRO) launched the second developmental flight of the Small Satellite Launch Vehicle (SSLV) on February 10, 2023, at 9:18 am IST. SSLV is ISRO's smallest launch vehicle. The mission, called SSLV-D2, or EOS-07, was launched from the First Launch Pad, Satish Dhawan Space Centre, Sriharikota, Andhra Pradesh. 

The maiden mission of SSLV, which was launched on August 7, 2022, had failed to place its payloads into the intended orbit. 

SSLV-D1, the first developmental flight of SSLV, was supposed to place two satellites into a 356-kilometre circular orbit. However, the satellites were instead placed into a 356 km × 76 km elliptical orbit. ISRO said that the issue was reasonably identified, and that the "failure of a logic to identify a sensor failure and go for a salvage action caused the deviation".

ISRO Chairman S Somanath had said that the Indian space agency will soon come back with the launch of the second developmental flight of SSLV, the SSLV-D2 mission. He also said that with SSLV-D2, ISRO is hoping to become completely successful in proving the capability of SSLV to place satellites in the intended orbit for commercial use. 

SSLV-D2 will be a 15-minute flight, and is intended to place satellites EOS-07 (Earth Observation Satellite-07), Janus-1 and AzaadiSAT-2 into a 450-kilometre orbit.

Over the years, ISRO has successfully realised five generations of launch vehicles, namely Satellite Launch Vehicle-3 (SLV-3), Augmented Satellite Launch Vehicle (ASLV), Polar Satellite Launch Vehicle (PSLV), Geosynchronous Satellite Launch Vehicle (GSLV), and GSLV Mark III. These launch vehicles have catered to national developmental needs, and enabled ISRO to develop and master critical technologies related to solid, liquid and cryogenic propulsion systems. 

ISRO developed SSLV to cater to the emerging global small satellite launch services market. SSLV has the capability to launch on demand. 

All About SSLV 

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). 

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. The launch vehicle is capable of launching payloads weighing up to 500 kilograms to low-Earth orbit (LEO). 

The key features of SSLV are low cost, flexibility in accommodating multiple satellites, 'launch on demand' feasibility, low turnaround time (the time taken to complete a process), minimal launch infrastructure requirements, and increased production rate from industries. 

Also, SSLV has the minimum launch pad occupancy, which means that integration of the vehicle and subsequent launch can be completed within 24 hours. 

SSLV has multiple satellite mounting options for nanosatellites, micro satellites, and mini satellites. The launch vehicle can carry a single satellite weighing up to 500 kilograms to a 500-kilometre planar orbit. 

SSLV can carry payload weighing up to 300 kilograms to Sun-synchronous orbit (SSO). 

The Velocity Trimming Module (VLT) is equipped with a payload adapter. The first, second, and third stages are known as SS1, SS2, and SS3, respectively. 

According to Gunter's Space Page, the first stage of SSLV is related to the Agni-3 and Agni-5 IRBM (Intermediate-range ballistic missile) motors, but has a new design. 

All About SSLV-D2 Mission

The objectives of the SSLV-D2 mission are the demonstration of a designed payload capacity of SSLV in low-Earth orbit, and the injection of an Earth Observation Satellite and two passenger satellites into a 450.7-kilometre circular orbit.

EOS-07 is a satellite designed and developed by ISRO. It weighs 156.3 kilograms. It was developed at U R Rao Satellite Centre (URSC), an ISRO centre for the design, development and construction of Indian satellites. EOS-7 is intended to be placed into orbit about 13 minutes after launch.

Janus-1 belongs to Antaris, a United States-based satellite software innovator. It weighs 11.5 kilograms. The satellite will be placed into orbit about 95 seconds after EOS-07 is successfully placed in the intended orbit. 

AzaadiSAT-2 has been developed by about 750 girl students across India. They were guided by Space Kidz India, Chennai. AzaadiSAT-2 weighs 8.7 kilograms.