Satellites with a mass of 500 kg or less are categorised as Small Satellites. Such satellites have wide-ranging significance for various areas of space applications. These satellites can operate in a solo mode or as a cluster of satellites positioned in Low-Earth Orbit (LEO, 400 to 800 km above the earth’s surface). Such clusters of small satellites have the ability to perform the same or similar set of functions as large satellites.
Small satellites come with major advantages like ease of launch and cost-effectiveness both in terms of development and production. Small satellites are generally used for earth observation (remote sensing), scientific experimentation and for the collection of meteorological data. They can also be used for other purposes such as radio relay, sending television signals or for the purposes of internet. While the life cycle of big satellites extends beyond 10 to 15 years, small satellites last around five years of less. Hence, there is more scope for incorporating new technologies particularly in the sensors arena and/or power source arena. In that sense, small satellites are always more advanced than the medium and big satellites that are in operation.
As per a standard convention, large satellites weigh more than 1,000 kg (1 tonne) while medium satellites fall in the range of 500 to 1000 kg. Small satellites are sub-classified according to their weight, orbit, purpose, etc.
Advancements in satellite miniaturisation have boosted the market for small satellites mainly because of the cost factor. Such satellites have utility across various sectors from social and commercial to the strategic. From the technological point of view, designing and developing small satellite capabilities is not very difficult. Today, even university students are developing such satellites.
Recent market forecasts have been very optimistic about the small satellite business. It has been projected that globally small satellite manufacturing and launch services over the period 2025-2027 could generate around US $35 billion to US $40 billion in revenues. The forecasts also project more than six to seven thousand new satellites launches during this period. The global focus is expected to shift towards launching clusters of small satellites rather than individual satellites. Other assessments are that this market could touch a staggering US $60 billion by 2030, with more than 10,000 small satellites in space.
In fact, scientists say the real challenge lies in developing specialised launch vehicles for small satellites. The market potential is so vast that some countries and commercial operators are focussing on establishing affordable and economical launch services.
India’s Space Research Organisation (ISRO) is developing a Small Satellite Launch Vehicle (SSLV), which is expected to be ready by the middle of this year. This vehicle, when fully developed, will place a 500 kg payload at a height of 500 km in the Low Earth Orbit (LEO). This payload could constitute a single 500 kg satellite or a cluster of small satellites together weighing 500 kg. The SSLV would have three solid stage motors and could be assembled both vertically and horizontally.
The development of this vehicle needs to be viewed at the backdrop of ISRO’s success in launching 269 satellites for 33 countries over many years. Only two of these satellites (SPOT 6 and SPOT 7) launched for France, had a launch mass of more than 700 kg, the rest had a launch mass of less than 500 kg, meaning they were predominantly small satellites.
It’s important to note that ISRO’s customers are spread all over the world, indicating the global acceptability of India’s launch services. Interestingly, although many European countries, and even the US, Japan and Israel, have their own satellite launch capabilities, they prefer to depend on India when launching their small satellites. This is essentially because ISRO launches are cost-effective and reliable.
In all these years, ISRO’s launch of small satellites for its foreign customers has been through the Polar Satellite Launch Vehicle (PSLV). Various variants of this vehicle are available and they have successfully positioned many satellites into different orbits. Normally, the PSLV carries 1,750 kg of payload into Sun-Synchronous Polar Orbit of 600 km altitude. ISRO has been using spare capacity of various launches to accommodate small satellites of international customers. Hence, on various occasions, such satellites were carried piggybacked to the main payload. But with the increase in global demand for small satellites, it was only a matter of time before ISRO would design a dedicated launch vehicle for such purposes. This vehicle is expected to cost one-tenth of the cost of the PSLV system.
Today, the requirement for high-resolution earth imaging is increasing rapidly, since various states are finding such information useful for precise management of their land, water and forest resources. In addition, the world is witnessing more natural disasters, possibly owing to global warming. Various space-based inputs providing forewarning of possible disasters and also for post-disaster management are extremely useful. This is pushing many countries to invest more in small satellite technology. Private business houses are also keen on real-time satellite inputs prior to undertaking new business ventures. Smaller countries with limited means, possibly also see investments in small satellites as a way of enhancing their prestige both internationally and domestically.
At present, some competition is being witnessed globally, to capture the small satellite launch market. The US, Israel and Russia have their small satellite launch vehicle programmes. Currently, the major global emphasis is towards developing a new internet business model using small satellites. This is because the spatial expansion of internet services is possible when the space-based internet becomes a reality.
ISRO’s SSLV is expected to take only 72 hours for integration of the entire system. This suggests that very shortly, India would have a space architecture allowing for almost a launch-on-demand facility. Such capability is an important need for the armed forces. It offers them an assurance that during war their requirements, both for communication and space reconnaissance, could be met almost in real-time. Small satellites have substantial strategic utility too, including potential counter-space capabilities.
Currently, significant research, developments and innovations are happening in the arena of space technologi. New developments are being witnessed in designing electric propulsion, optical telecommunications, sensor technologies and artificial intelligence systems. All this will feed the growth and expansion of small satellite systems.
(The author is Senior Fellow in the Institute for Defence Studies and Analyses and heads its Centre on Strategic Technologies. Views are personal.)
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