Small is Beautiful in Space

At 1801 hrs on 25 February 2013, ISRO launched Polar Satellite Launch Vehicle-C20, which put into orbit seven satellites, totally weighing around 700 kg. The primary load was a 409 kg SARAL (Satellite with ARgos and ALtika), an ISRO-CNES (France) collaborative satellite. SARAL consists of an Indian platform and transponder, with two independent French payloads that will conduct oceanographic studies. Six satellites comprising the secondary load are SAPHHIRE and NEOSSat (both Canadian), BRITE and UniBRITE (both Austrian), STRaND (Britain) and AAUSAT (Denmark). Their roles range from space based surveillance to in-orbit technology demonstration and testing.

This launch, as many others in recent times, has brought into focus smaller satellites, of less than 500 kg weight, that are revolutionising the realm of space. The generally accepted definitions of satellite classes of weight less than 500 kg are:

• Small satellites or minisatellites - 100 to 500 kg.
•  microsatellites - 10-100 kg;
•  nanosatellites - One to 10 kg.
•  picosatellites - 100 gm to one kg.
• Femtosatellites - 10 to 100 grams.  

Beginning with Sputnik (Sputnik 1 weighed only 83.6 kilograms), earlier satellites were all small. The sizes continued to increase with increasing capabilities and this was ably supported by constantly improving payload capabilities of launch vehicles. That most satellites were government or military operated further ensured that these standalone systems were big, complex and expensive. Such large satellites, with their associated requirements, restricted the technological and economic capability of space exploration to a few larger nations and also precluded commercial interest.

The shift from tubes to transistors commenced the movement towards ‘small’ in anything related to electronics; resulting in corresponding interest in smaller satellites in the 1980s. But it was the commercial involvement in the technology that accelerated this swing. UoSAT-5, built by Surrey Satellite Technology Ltd (SSTL) of the United Kingdom and launched in 1991, was the first commercial microsatellite. Experts had dismissed the early forays into microsatellites as of little use other than academic experimentation, while warning of the concurrent increase of the orbital debris nuisance. Defying the naysayers however, since then several technology demonstrators and operational micro satellites have been launched. Unlike in the past when military employment formed the basis for most research, development in the field of microsatellites has been stimulated by advances in commercial spheres of electronics, miniaturization techniques and in the field of nanotechnology.

Regular advancements in the relevant fields have made micro satellites ever more capable of performing complex scientific functions, communications and Earth observation missions. Besides contributing to the conventional roles, they have also spurred thinking on innovative applications that could exploit their size and capabilities. Some of the orbital applications that are being envisaged are missions such as visual and IR inspection of space objects, jamming of communications satellites, electronic intelligence (ELINT) gathering, anti- satellite operations and satellite assistance.

Smaller satellites have truly encouraged the concept of constellations replacing standalone systems. These are collective arrays of satellites that when functioning in a synchronized fashion exhibit collective behaviours and performances substantially greater than the sum of their individual abilities. Some constellations, besides those employed for Global Positioning System (GPS), are already operational providing support to communication, remote sensing and disaster management. Such constellations, displaced in orbits, are more responsive, provide wider coverage and shortened revisit times and improve redundancy. Future applications being developed include Distributed Space Systems that envisage exploitation of multiple space platforms flying in formation that could enhance the total capability through digital wireless signal transfer and integration. They could either simulate larger seamless antennae for communication and ELINT or larger virtual apertures for surveillance.

Designing and deployment of nano satellites got a shot in the arm with the CubeSats concept that follows a standardised configuration of satellites (basic single unit (1U) being 10 × 10 × 10 cm with a mass of about 1 kg). The subsequent promulgation and acceptance of this standard by most government, commercial and scientific nanosatellite manufacturers as well as launch operators has facilitated integration of these satellites as secondary or tertiary loads with existing payloads, on varied launch vehicles. CubeSat design additionally provides flexibility in design as more than one unit can be amalgamated into larger – but still very small – spacecraft for varied applications. 

Similar technological innovations would also make possible microlaunch vehicles of relatively very low lift off weight that will bring down per unit launch costs significantly. Microlaunch vehicles would in turn enable single launch missions for microsatellites as also afford faster-response launch capability to provide redundancy against natural and manmade threats in space. They would also allow flexibility of multiple launch areas for tactical missions.

Microsatellites that use new age technologies facilitate smaller development schedules, ease of production and increased robustness through use of composites. They potentially provide an ideal test bed for technology verification prior to larger investments in development programmes. The biggest advantage however is that they have the potential to ‘Democratise Space’, by allowing an increasing number of less developed countries and private players to gain technological expertise and to build capacity in space technology. While advanced countries see this proliferation as a challenge to their security (and domination), the contrary view welcomes the increased transparency, arguing that improved awareness would bring down the distrust among nations. Ability to conduct single-purpose missions in the future would also permit cost effective work to focus on specific areas of interest, thus empowering lesser affluent countries, businesses, communities or societies.

These developments have energised the commercial interest in the sector. There is continuous development taking place in the fields of miniaturisation owing to the high degree of competition among companies. Private manufacturers’ strategy has been to rely more on Commercial off the Shelf (COTS) components and turnkey solutions to keep their costs low. Market estimates expect the current yearly launch average of nano/microsatellites of around 23 units per year to increase to about 100 to 142 (1-50 kg) launches globally by 2020, with an increasing participation by emerging countries and newer companies. While governments and private players can directly take advantage of these developments, military programmes can benefit from the dual use applications while restricting their own research to technology areas that have stringent ‘military only’ applications.  

While the sector holds immense potential, there are still challenges in design and fabrication capabilities which need to be overcome for transitioning of these technologies to a low-cost, robust, manufacturing-based industry. Also, while pursuing these technologies, care has to be taken not to let low cost lead to low quality. Adding more number of objects into space with their relatively shorter life spans has the potential to increase the problem of bandwidth sharing and space debris. Appropriate debris mitigation efforts, technical, operational and legal, thus need to be worked upon concurrently.

Increasing use of micro satellites is good news for the Indian Space Research Organisation (ISRO), which has a competitive edge with its cost-effective Polar Satellite Launch Vehicle (PSLV). The agency has been supporting research and academic pursuits in the field of smaller satellites and has launched satellites built by university students under its guidance. ISRO releases claim that development of micro and nano satellites for specific applications is being seen as an ideal opportunity for participation by private companies.

However, most of these initiatives are at a nascent stage. Satellites launched by ISRO are mostly student efforts with academic roles. Even SARAL uses only an ISRO platform while the payload is French. With the indigenous development of GSLV’s cryogenic engine and GSLV III still sometime away, India still has to depend on foreign craft to launch its heavier satellites. This dependence does not augur well for India’s space sufficiency, either strategically or economically. The benefits that smaller satellites offer thus need serious consideration and investment. Cost benefit should not be the only driving force and their ability to invigorate application in different fields should be explored. Years of operating as a standalone agency has to give way to much more private participation as also further international collaborations with like minded countries. Indian private sector’s expansion in soft skills in recent years as well as the academic prowess from the colleges needs to be tapped adequately. End users, that include all government departments and private enterprises, need to be involved at appropriate stages of development.  

Microsatellites have the potential to revolutionise the space arena in almost all aspects. Their development in recent years has forced a rethink on space based resources, their development, deployment and employability. Their affect on the strategic and military space cannot be underestimated. India as an emerging country with its strong presence in space needs to prioritise efforts in this field to benefit from the cost effectiveness and flexible employability of the futuristic technologies. 

The author is a Senior Fellow at CLAWS

Views expressed are personal