Advances in Materials and Devices for Satellite Communications: Materials for Launch Vehicles

Technology Primer

Television broadcasts, communications using cellular phones, weather forecasting, safer navigation systems for ships, airplanes, and cars are some of the areas that have immensely benefitted by the growth of the satellite communication industry. The industry is witnessing more and more applications being made possible by using satellite technology. It is being used to provide communication for first responders in case of emergencies, used for tracking of goods in transit, and so on. However, all these would be possible only if the satellite developed for the purpose is successfully placed into orbit in space. A carrier required to deliver a satellite into orbit is typically known as a launch vehicle.

A launch vehicle is a rocket that can carry and deliver a payload into space from a planetary surface. Launch vehicles are broadly classified as

• Expandable launch vehicles (ELV)
• Reusable launch vehicles (RLV)
• Single stage to orbit (SSTO)
• Two stage to orbit (TSTO) or double/dual stage to orbit (DSTO)

An expandable launch vehicle can be used only once to deliver a payload into space. In this type of launch vehicle the entire vehicle is discarded at different stages during its flight. The ELV systems are slowly discarded one by one at various stages (multistage rocket). This type of launching seems to be expensive but is better than existing RLVs.

RLVs can be used more than once to deliver payload into space. SSTO vehicles spend only the propellants and fluids required to power themselves to go into orbit directly without discarding any other piece of hardware at any stage. SSTO is usually refers to reusable vehicles.

A TSTO spacecraft consists of two stages: the first stage is used at the lift-off stage to accelerate the vehicle and gets detached later at a programmed altitude, while the second stage launches the payload into orbit under its own power.

Countries such as the United States, Commonwealth of Independent States (erstwhile USSR), Japan, China, France, India, Brazil, and European countries and others are actively working on developing next generation launch vehicles. To construct a launch vehicle that could deliver a payload in space is not an easy task as it requires use of a variety of advanced materials for component specific applications. Such vehicles also need to be able to withstand the harsh and turbulent atmosphere, right from lift-off to launching the satellite in orbit (and re-entry in case of an RLV). Parts of the vehicles have to withstand very high temperatures during propulsion in their journey against the gravitational pull. The external body of the launch vehicle should protect the electronic systems that are carried by the launch vehicle.