By Dr. Gary Deel, Ph.D., J.D.
Faculty Director, School of Business, American Military University
This article is the second of a five-part series profiling the Indian Space Research Organization (ISRO). This series looks at the past, present, and future of ISRO and why the global space exploration community should keep an eye on this rising star. This article explores launch vehicles that ISRO has developed over the years.
Over several decades, ISRO has relied on a variety of different launch vehicles to handle its diverse mission needs. Its first launch vehicle was Satellite Launch Vehicle-3 (SLV-3), which ISRO successfully launched for the first time in 1980, making India the sixth world nation to have spacefaring capabilities. SLV-3 was a four-stage, all-solid-rocket-fuel vehicle that weighed 17 tons, stood 22 meters high and was capable of lofting 40 kg payloads into orbit.
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The next launch vehicle to be added to ISRO’s arsenal was the Augmented Satellite Launch Vehicle (ASLV), which first launched in 1987. ASLV was something of a big brother to SLV. It stood 24 meters tall, weighed 40 tons and could lift up to 150 kg of payload into orbits extending out to 400km in altitude.
ISRO Heavy Lift Rockets for Modern Missions
SLV and ASLV have since been retired, however. Today, ISRO relies on a new suite of launch vehicle to accomplish modern missions.
One such rocket is the Polar Satellite Launch Vehicle (PSLV). The PSLV was first launched in 1993, and it was the first ISRO rocket to feature liquid propellant motors. It stood 44 meters tall, weighed an estimated 320 tons in its heaviest configuration and was capable of launching 1,750 kg of payload to orbits as high as 600 km.
PSLV consisted of four stages – two liquid-fueled and two solid-fueled. It could also be augmented with six solid rocket fuel strap-on motors for really heavy lifting.
As of 2017, PSLV has completed dozens of successful missions, launching almost 50 satellites for India and more than 200 satellites for Antrix customers from around the world. It has only failed on two launch occasions.
Another current ISRO rocket is the Geosynchronous Launch Vehicle (GSLV), also known as GSLV Mk II. It is the largest of the agency’s launch vehicles, standing at almost 50 meters tall and weighing more than 400 tons on the launch pad.
The GSLV Mk II consists of three stages, the first being solid-fueled and the second and third being liquid-fueled. The third stage is a unique cryogenic engine, developed by Indian engineers, called the Cryogenic Upper Stage Project (CUSP).
Like PSLV, GSLV can be bolstered with four liquid-fueled strap-on motors. GSLV can lift up to five tons of payload to low-Earth orbit and up to 2.5 tons to geosynchronous transfer orbits.
GSLV first flew in 2001. It has been used for 13 missions so far, and 10 of them have been successful.
The Geosynchronous Launch Vehicle – Mark III (GSLV Mk III) was built after its predecessor for different mission applications. It stands 43 meters high, but weighs 640 tons on the launchpad.
The GSLV Mk III consists of two liquid-fueled stages (including another cryogenic engine for the upper stage) and two solid-fueled side boosters. It is capable of launching 8,000 kg to low-Earth orbit and 4,000 kg to geosynchronous transfer orbits.
GSLV Mk III’s first successful launch was in 2014. To date, it has completed four successful missions.
ISRO’s Sounding Rockets for Atmospheric Research and Technology Testing
In addition to ISRO’s heavy lift rockets, the IRSO arsenal includes a variety of sounding rockets used for atmospheric research and testing new technologies. ISRO manufactures three sizes of sounding rocket – the RH-200, RH-300 Mk II and RH 560 Mk II. These rockets are capable of lifting payloads between 10 kg and 100 kg to various altitudes.
In addition to ISRO’s current fleet of rockets, it is looking ahead to the future with prototype designs. Chief among them is the Reusable Launch Vehicle – Technology Demonstrator (RLV-TD).
Taking a cue from American private space launch contractor SpaceX, India built the RLV-TD to test their ability to return rocket components from space for rapid reuse, which yields significant improvements in costs and time efficiency. Reusability is definitely a key ingredient for the future of space launch vehicles, so this is a smart investment on ISRO’s part.
The RLV-TD rocket stands 17 meters tall. It consists of a solid-fueled, first-stage booster supporting a space plane-style upper-stage complete with double delta wings and ailerons.
In 2016, ISRO successfully launched a prototype of RLV-TD. The first-stage booster was allowed to fall into the ocean off the coast of India, and the space plane upper stage glided to a soft landing in the water as well. All components of the mission went as planned, so this achievement was considered a massive success.
In the next tests for RLV-TD, ISRO will attempt to recover its first-stage booster with a retrorocket landing in the same way that SpaceX’s Falcon 9 boosters normally land. If ISRO accomplishes this goal, it will be the first national space agency to return a first-stage booster safely for reuse. ISRO also plans to drop the space plane upper stage from a helicopter several miles above the Earth and test its ability to glide to a safe landing on a runway in India.
In 2016, ISRO tested another technology they are developing: the Scramjet Engine. The Scramjet uses hydrogen as fuel, but it is unique because it pulls oxygen from the air around it as an oxidizer for the combustion process. The 2016 launch was a successful test of the technology, and India plans to continue pursuit of this technology.
Currently, liquid-fueled rockets use supercooled liquid oxygen in onboard tanks for oxidizing combustion. So if the Scramjet works, it could revolutionize the way modern heavy rockets are designed.
In the next installment of this article series, we’ll explore some of the most important missions that ISRO has undertaken over the last 50 years.
About the Author
Dr. Gary Deel is a Faculty Director with the School of Business at American Military University. He holds a J.D. in Law and a Ph.D. in Hospitality/Business Management. Gary teaches human resources and employment law classes for American Military University, the University of Central Florida, Colorado State University and others.