ISRO’s Small Satellite Launch Vehicle Mission

The Indian Space Research Organisation (ISRO) launched the first flight of its new satellite launcher, Small Satellite Launch Vehicle from the Satish Dhawan Space Centre in Sriharikota, Andhra Pradesh carrying two satellites - Earth Observation Satellite-2 (EOS-2) and AzadiSAT.

Satellites carried by the vehicle, however, failed to reach the desired orbit due to an error in the terminal stage.

What was the Purpose of the Mission?

• The purpose of this mission was to place the two satellites in circular low-earth orbits at a height of about 350 km above the Equator.
  • EOS-2: An optical remote sensing satellite designed and developed by ISRO.
  • AzadiSAT: Array of 75 tiny payloads integrated by students, to measure the ionising radiation, integrated by the student team of Space Kidz India.
    • It is ISRO's attempt at popularising Science Technology Engineering Mathematics (STEM) among girl students at the school level as it pushes for further exploration of the cosmos.

What went Wrong During the Satellite Launch?

• The SSLV was composed of three stages with velocity trimming modules powered by solid fuels and these three performed their function as planned.
• The problem appeared to be the SSLV’s terminal stage, called the velocity trimming module (VTM).
  • According to the launch profile, the VTM was supposed to have burned for 20 seconds.
  • However, it burnt for only 0.1 seconds, denying the rocket of the requisite altitude boost.
• According to ISRO, the malfunctioning of a sensor resulted in placing the satellites in an elliptical orbit, rather than a circular orbit.

What is the Difference Between Circular and Elliptical Orbits?

• Orbit: An orbit is a regular, repeating path that one object in space takes around another one.
  • Elliptical: When an object moves around another object in an oval-shaped path.
    • Most planets in our solar system have elliptical orbits rather than circular orbits due to the gravitational interactions of other planets and stars.
  • Circular: A circular orbit is an orbit with a fixed distance around the barycenter, in the shape of a circle.
    • Artificial satellites that orbit the Earth are mostly placed in circular orbits.
• Circular path is favourable for artificial satellites because it is easier to image the Earth if the satellite is at a fixed distance from it.
  • If the distance keeps changing as in an elliptical orbit, keeping the cameras focussed can become complicated.

How is SSLV Different From PSLV?

• Cost-effective and Payload Capacity: SSLV has been designed to launch a 500-kilogram payload into a 500-kilometre planar orbit plus it is less expensive than PSLV.
  • As the PSLV (Polar Satellite Launch Vehicle) can carry huge loads, small projects don't have a high cost-benefit ratio.
• Solid Propellant: The SSLV uses solid propellants and this is more economical and easier to handle than the liquid propellant stages of the PSLV.
• Faster Launch on Demand Service: PSLV's long turnaround time (over 60 days) makes scaling up launch on demand launches difficult.
  • The SSLV has the flexibility to launch multiple satellites. Ithas a low turnaround time (72 hours) and can be assembled within a fortnight, allowing the space agency to provide launch on demand service in the fast growing low earth orbit launch sector.

What are the Future Potentials?

• Doorway Commercial Satellite Launch Market: The SSLV is India’s official doorway into the commercial small satellite launch market around the world.
  • The rocket is expected to be operated by New Space India Limited (NSIL), India’s commercial space operations arm.
    • Attractive for commercial earth observation and communication.
• Launch of the SSLV from Pole to Pole: ISRO intends to launch the SSLV in future from its upcoming spaceport in Kulasekarapattinam in Tamil Nadu.
  • Doing so would allow SSLV to enter into a pole-to-pole, or polar orbit around the Earth.
    • The SSLV will take off over the Lakshadweep Sea without manoeuvring around Sri Lanka , saving fuel and payload capacity.
• Towards Nano-Satellites Launch Vehicle: With the advancement of technology, the size of satellites has come down significantly with CubeSats and nano-satellites becoming the norm of the day.
  • ISRO has the opportunity to lead the development of cost-effective nano-satellite launch vehicles.

Drishti Mains Question Explain how Small Satellite Launch Vehicle is different from other launch vehicles.