A Satellite Launch Vehicle (SLV) is a kind of rocket that lifts satellites into space and deposits them in specified orbits. These vehicles provide important services in terms of launching communication satellites, weather satellites, navigation satellites, and research satellites. SLVs come in different sizes and capabilities to tend to all the different applications and payloads.
About Launch Vehicle Programme of India
- ISRO’s Launch Vehicle Programme caters to the development of indigenous rockets to place satellites in orbit.
- The program started in 1980 with the SLV, which was followed by the ASLV. Coming in the 1990s, the PSLV has been a dependable workhorse for launching all kinds of satellites for foreign clients.
- The GSLV and its modern version, the GSLV Mk III, launch heavier payloads as well as undertake interplanetary missions.
- The country’s newest birth, the SSLV, provides fast and inexpensive launches of small satellites, furthering the development of space prowess.
Key Facts about Satellite Launch Vehicles (SLVs)
- Purpose: SLVs are used to launch satellites into specified orbits around the earth or even further.
- Kind of Orbits: The usual target orbits are LEO, GEO, and Polar.
- Stages: Most of these SLVs have multistages-they have different engines and propellants in each stage, discarding the previous stage as it ascends.
- Propulsion: They operate on thrust derived from solid, liquid, hybrid, or cryogenic propellants.
- Reusable SLVs: Some of the modern SLVs, such as SpaceX’s Falcon 9, are kept partially reusable so as to reduce cost.
- Achievements by India: Meanwhile, more than 300 satellites have been launched by India’s PSLV, and the GSLV has launched the Chandrayaan and Mangalyaan missions.
- Launch Sites: Launch vehicles need launch pads and ground infrastructures of their own specifications.
- Global Competition: The U.S. Russia, China, India, in satellite launch, commercial, or government.
- SSLV Trend: Smaller launchers are becoming popular to launch small- and nano-satellites fast and efficiently.
- Challenges: To face these challenges, accurate engineering is required for dealing with atmospheric drag, gravity, and complex orbital insertion.
Advanced Satellites Launch Vehicles
Satellite Launch Vehicle (SLV)
- The SLV project was born out of the need for achieving indigenous satellite launch capability for communication, remote-sensing and meteorology. Satellite Launch Vehicle-3 (SLV-3) was the first experimental satellite launch vehicle. It was an all solid, four stage vehicle weighing 17 tonnes with a height of 22m and capable of placing 40 kg class payloads in Low Earth Orbit (LEO).
- After many successful launches, the SLV project culminated, paving the way to advanced launch vehicle project such as Augmented Satellite Launch Vehicle (ASLV), Polar Satellite Launch Vehicle (PSLV) and Geosynchronous Satellite Launch Vehicle (GSLV).
Augmented Satellite Launch Vehicle (ASLV)
- The ASLV was made to carry heavier payload than SLV-3. With a lift off weight of 40 ton, the 24m tall ASLV was configured as a five stage, all solid propellant vehicle, with a payload capability of 150 kg into the 400 km LEO. It proved to be a low-cost intermediate vehicle to demonstrate and validate critical technologies like strap-on technology, inertial navigation, bulbous heat shield, vertical integration, closed loop guidance, etc.
Polar Satellite Launch Vehicle (PSLV)
- Polar Satellite Launch Vehicle is the third generation launch vehicle of India. It is the first Indian launch vehicle to be equipped with liquid stages and the first launcher to gain operational status. It is a 44m tall vehicle, with lift-off mass of 295 ton. It is configured as a four stage, alternate solid and liquid propellant vehicle.
- It can take up to 1,750 kg of payload to Sun-Synchronous Polar Orbits of 600 km altitude. PSLV uses 6 solid rocket strap-on motors to augment the thrust provided by the first stage in its PSLV-G and PSLV-XL variants. However, strap-ons are not used in the core alone version (PSLV-CA).
- The PSLV has proven to be a reliable and versatile vehicle for diverse missions. As of 14 February 2022, the PSLV had completed 54 launches, with 51 successfully reaching their planned orbits. The fact that PSLV was used to place Chandrayaan-1 and Mangalyaan to the Moon and the Mars respectively, is a testimony of its versatility and reliability.
Geosynchronous Satellite Launch Vehicle (GSLV)
- Geosynchronous Satellite Launch Vehicle is the largest launch vehicle developed by India. This fourth generation launch vehicle is a three stage vehicle with indigenously developed Cryogenic Upper Stage (CUS), which is flight proven.
ISRO has renamed the GSLV-Mark III as LVM3 mainly to identify etc of placing satellites into a variety of orbits.
- ISRO has designed 3 staged programmes for the development of GSLV, i.e. GSLV-MK I, GSLV- MK II and GSLV- MK III. GSLV MK III is the heaviest and most powerful launch vehicle. It is 43 m tall, with lift off mass of 640 ton. It has a payload capacity of 4-5 tonnes for Geosynchronous Transfer Orbit (GTO) or about 10 tons to Low Earth Orbit (LEO), which is about twice the capability of the GSLV Mk II. It was used to launch Chandrayaan-2 spacecraft.
Reusable Launch Vehicle – Technology Demonstrator (RLV-TD)
- The RLV-TD is a series of technology demonstration missions that have been considered as a first step towards realizing a Two Stage To Orbit (TSTO) fully re-usable vehicle. The Reusable Launch Vehicle is like a winged aircraft that has been configured to act as a flying test bed to evaluate various technologies, namely, hypersonic flight, autonomous landing, powered cruise flight and hypersonic flight using air-breathing propulsion.
- This technology is being developed in phases through a series of experimental flights. The first in the series of experimental flights is the Hypersonic Flight Experiment (HEX) followed by the Landing Experiment (LEX), Return Flight Experiment (REX) and Scramjet Propulsion Experiment (SPEX).
| SOUNDING ROCKETS Sounding rockets are one or two stage solid propellant rockets used for probing the upper atmospheric regions and for space research. They also serve as easily affordable platforms to test or prove prototypes of new components or subsystems intended for use in launch vehicles and satellites. The launch of the first sounding rocket from Thumba near Thiruvananthapuram, Kerala on 21 November 1963, marked the beginning of the Indian Space Programme. |
Applications of Satellite Launch Vehicles
- Communication Satellites:
- They facilitate broadcasting of TV shows, Internet connectivity, and telecommunication networks on a global scale.
- Earth Observation and Remote Sensing:
- They are used to monitor processes such as climate, natural disasters, agriculture, and urban development.
- Navigation Satellites:
- GPS, GLONASS, and India-specific NavIC systems are positioned and guided under the accurate navigation service.
- Weather Satellites:
- They collect meteorological data useful in the prediction of weather patterns, monitoring of cyclones or storms.
- Scientific Research:
- Enable space missions and experiments to study Earth’s atmosphere, outer space, and celestial bodies.
- Defense and Surveillance:
- Deploy military satellites in reconnaissance, communication, and early warning systems.
- Commercial Satellite Launch Services:
- Countries/private companies providing SLV Services for launching satellites on behalf of their clients worldwide.
- Interplanetary Exploration:
- Such as from Moon to Mars and beyond, like ISRO’s Chandrayaan and Mangalyaan missions.
- Space Tourism and Human Missions:
- Future SLVs will be used to support human spaceflight and space tourism activities.
- Small Sat Deployment:
- SLVs such as SSLV are capable of launching nanosatellites for education and research.
Way Forward
- Reusability, cost projects, and miniaturization mark the moon’s future for satellite launch vehicles. With the occurrence of reusable rockets, launch costs will keep plummeting, and hence missions will be more frequent. Thus, smaller modular vehicles like SSLVs would fit launch demand coming from nanosatellites. They will thus encourage innovations.
- Green propellants would make launches environmentally friendly. 3D printing for rocket parts, AI-driven launch systems, and the like will further prop up reliability and efficiency.
Conclusion
Moving into the realm of technology and involving the mighty machines that carry satellites into orbit, an SLV or Satellite Launch Vehicle is basically the device that empowers space exploration, communication, and global connectivity. They are the vehicles for launching satellites for myriad uses: navigation, weather, scientific research, and defense.
With emerging technologies like reusable rockets and small satellite launchers, SLVs are growing to be more effective and economical. This technology is being targeted by both countries and private players, which is a major incentive for innovation and competitive drive. As space exploration takes a step forward, SLVs will surely enhance the already stretched presence to conquer new targets.
Further Reading:- Satellites: Size, Types & More
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