Small Satellite Launch Vehicle (SSLV)

• The Earth observation satellite EOS-02 and a student satellite called AzaadiSAT were carried on the inaugural flight of the Small Satellite Launch Vehicle (SSLV) that the Indian Space Research Organization (ISRO) recently launched.
• However, because the satellites were already separated from the launch vehicle, the mission failed to deploy them in the necessary orbits.

Image Source - Iasgyaan

What is a Small Satellite Launch Vehicle?

• A three-stage launch vehicle called the Small Satellite Launch Vehicle (SSLV) is designed with three solid propulsion stages and a terminal stage called the Velocity Trimming Module (VTM) that uses liquid propulsion.
• The SSLV has a 2 m diameter, is 34 m long, and weighs about 120 tonnes when it lifts off.
• From Satish Dhawan Space Center, SSLV is capable of launching 500kg satellites into 500km-planar orbit (SDSC).

Key Features:

• Low cost,
• The low turn-around time,
• Flexibility in accommodating multiple satellites,
• Launch demand feasibility,
• Minimal launch infrastructure requirements, etc

Aim:

• A small satellite launch vehicle (SSLV) designed by ISRO allows for the "launch-on-demand" launch of satellites weighing up to 500 kg into low Earth orbit.
• Mini, Micro, or Nanosatellites (10 to 500 kg mass) can be launched by SSLV into a 500 km planar orbit.

Significance

The Age of Small Satellites:

• Previously, larger satellite payloads were prioritized, but as the industry evolved, a variety of stakeholders, including businesses, governments, colleges, and laboratories, started launching satellites. They are all primarily classified as tiny satellites.

The Rise in Demand:

• Over the past eight to ten years, there has been a sharp rise in the demand for small satellite launches as a result of the expanding demand for space-based data, communication, surveillance, and commerce.

• Saves money: Satellite producers and operators do not have the luxury of booking months in advance or incurring astronomical travel costs.
• As a result, organizations are building satellite constellations in orbit.
• One Web and SpaceX's Starlink are two initiatives building a constellation of several satellites.

Opportunity:

• Since the majority of the demand comes from businesses launching satellites for commercial purposes, there is now a business opportunity for space organizations like ISRO to capitalize on the sector's potential due to the rise in demand for rocket launches.

What was the Issue?

• The velocity trimming module (VTM), the SSLV's terminal stage, seemed to be the source of the issue.
• At 653 seconds after launch, the VTM was scheduled to have burned for 20 seconds in accordance with the launch profile.
• It only burned for 0.1 seconds though, depriving the rocket of the necessary height boost.
• After the VTM burnt, the two satellites disengaged from the vehicle. A sensor fault caused the satellites to be placed in an elliptical orbit as opposed to a circular orbit.
• According to ISRO, both satellites were successfully injected, and all steps ran smoothly. However, the orbit obtained was less than anticipated, making it unstable.

What is the SSLV-D1/EOS-02 Mission?

• With the ability to launch satellites into Low Earth Orbit, it was designed to capture a larger share of the market for small launch vehicles.
• The rocket was transporting the two satellites.
• The primary EOS-2 Earth-observing spacecraft, called EOS-02, was created and launched by ISRO.
• Advanced optical remote sensing with the great spatial resolution is available on this Microsat class satellite.
• The second student satellite for AzaadiSAT is an 8U Cubesat that weighs about 8 kg.
• It conducts Femto experiments and carries 75 distinct payloads, each weighing about 50 grams.
• It carried out minute tests that would have determined the amount of ionizing radiation in its orbit, as well as a transponder that operated on the ham radio frequency to make it accessible to amateur users.
• These payloads were constructed with assistance from female students from remote areas of the nation.
• Does the "Space Kidz India" student team integrate the payloads?

What is the Difference between Circular and Elliptical Orbits?

Elliptical Orbits:

• Typically, spacecraft and satellites are placed in elliptical orbits only briefly.
• Then, either they are propelled higher into circular orbits or the acceleration is increased until the trajectory shifts from an ellipse to a hyperbola, allowing the spaceship to escape the gravity of the Earth and travel farther into space, such as to the Moon or Mars, or farther still.

Circular Orbits:

• satellites that circle the Earth are typically put into circular orbits.
• One argument is that it is simpler if the satellite has a set distance from the Earth if it is used to image the planet.
• Keeping the cameras focused can be challenging if the distance is constantly shifting, as it would be in an elliptical orbit.

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