Military Satellite Trends And Outlook: Part 2

By Asif Anwar

This is the second part of a two-part guest column. Click here to read Part 1

Small Satellites Increasing In Profile

Military satellite technical advances include a move to smaller platforms. Small satellites provide a range of benefits in terms of smaller mass, rapid deployment time, lower cost, and utility. These advantages are being used by emerging nations as they enable faster penetration into space at lower cost. It is estimated that up to 62 nations have now launched satellites with an emphasis on smaller platforms. At the same time, traditional players are also starting to look at small satellites to leverage the flexibility and value-for-money offered to augment existing satellite systems.

In Europe, the United Kingdom has been one of the pioneering nations in developing small satellites over the past 30 years.  UK-based Surrey Satellite Technology Ltd (SSTL), established in 1985 and acquired by EADS in 2009, has worked on pioneering the small satellite approach, with a focus on providing end-to-end capabilities comprising design, manufacture, integration, test, orbital operations, and launch services, all underpinned by fast turnaround times.

Early applications for small satellites have covered imaging, communications, and signals intelligence (SIGINT). The SNAP-1 nanosatellite, launched in 1998, was an imaging platform, while the French ESSAIM System was designed for ELINT (electronic signals intelligence) missions. Other applications for small satellites have included atmospheric research and monitoring space weather. Small satellites have also been used to provide the “internet in space.” UoSAT-12, launched in 2001, was used as a web server in space to transfer real-time telemetry and stored image data directly to the user, while in 2005 the UK-DMC carried a Cisco router.

One of the key advantages cited for small satellites is the affordability of constellations and the use of small satellites in swarms. Small satellite constellations can offer rapid revisit times over target areas and, when used in conjunction with overlapping orbits, allow large areas to be covered. The use of satellite swarms offer advantages of increased aperture for imaging applications.

Examples of small satellite constellations include the Disaster Monitoring Constellation (DMC). The individual satellites are operated under the basis of individual country ownership, and this is coupled with collaborative operation to allow data sharing and exchange of global images that are gathered daily and used for national, disaster, and commercial use. The first generation of DMC small satellites were launched in 2003 and were operated by Algeria, Nigeria, Turkey, and the UK, and have since been retired. The current batch of DMC satellites are owned by China, Nigeria (two satellites), Spain, and the UK.

The United States also has a range of programs looking at the applicability of small satellites. As an example, the Operationally Responsive Space (ORS) Office, created in 2007, is a joint initiative of several agencies within the United States Department of Defense (DoD). The primary objective of the ORS office is to develop end-to-end capabilities and provide space assets in a cost effective and timely fashion using a modular open system architecture (MOSA) making use of reconfigurable, modular bus, and payload systems.

The payloads are based around a RF family and an EO/IR family. The RF family incorporates the RF electronics, processing electronics, RF feeds and multiband reflector for missions involving communications, tactical electronic support, and battlespace awareness. Similarly, the EO/IR family incorporates the electronics, filter assembly, focal plane assembly, and multifunction telescope to support imaging, spectral sensing, surveillance, and blue force tracking missions. Both families are designed to be plug-and-play payloads that can be incorporated onto a prefabricated modular bus structure and space plug and play avionics (SPA) backplane.

Over the past four years, ORS has had four launches including TacSat-4, which was launched in 2011 to provide COTM (communications on the move). Placed in an elliptical orbit with a peak at 12,000 km, the satellite is able to make three passes per day over a given location, providing an average of two hours of COTM at the location without the need for user antenna pointing. Through these launches, ORS has demonstrated that small satellites have military utility for the US.

Advances in small satellite technology have elevated the status of small satellites from just being “military relevant” to “laptop in space” platforms that can offer capabilities and advantages over traditional platforms in certain operational environs. As well as being able to showcase continued advancement in technologies, small satellites are also providing monetary benefits, especially with budgetary constraints a growing primary consideration. From an operational perspective, small satellites present another layer of surveillance complementing the close-up view that can be provided with tactical UAVs (unmanned aerial vehicles) with situational awareness.

Technology Trends For Military Satellites

Commercial satellite communications occurs in three primary bands: C, Ku, and Ka. In addition to these frequency bands, military satellite systems also make extensive use of X-band communications frequencies. Typical military satellite communications have been focused on C band and X band, but these bands are not only expensive (especially the military-specific X band) but are also increasingly capacity constrained. With additional BLOS (beyond line of sight) requirements coming from UAV platforms and a continuing growth in intelligence requirements, demand for bandwidth is continuing to increase, and this has resulted in military satellite communications making use of expensive solutions over military X band as well as Ku band.

Consequently, emerging military and civilian Ka-band technologies are also being actively considered. The use of Ka-band allows higher upload and download data rates and better spectral efficiencies, while at the same time taking advantage of significantly less congestion in the spectrum band. Significantly, this also lowers bandwidth cost.

In Europe, UK-based Avanti Communications is leveraging growing demand for data based communications by offering services on Ka-band satellites. The company launched HYLAS 1 in November 2010 to cover Europe and this was followed in 2012 with the launch of HYLAS 2. Avanti has been working with the UK MOD through Paradigm to test military Ka-band communications based on HYLAS 1 services.

There are a range of payload technologies used for applications such as imaging, communications, and signals intelligence, and emerging technologies are helping to drive future platform development.

Technology enhancements at the component and system level include gallium arsenide (GaAs) based triple junction solar cells, gallium nitride (GaN) based power amplifiers, and the use of phased array antennas. Additional areas being examined include the use of intersatellite link systems to provide near real-time capabilities for satellite control, monitoring satellite telemetry and returning data. The utilization of commercial-off-the-shelf (COTS) components is also becoming more prevalent, and onboard processing is one area using COTS-based technologies to increase data delivery speed and reduce data rates and bandwidth rates, as well as the associated power requirements.

The use of synthetic aperture radar (SAR) imagery is also starting to be applied for smaller satellite platforms. As an example, the UK-funded NovaSAR constellation will comprise a 450kg satellite with an S-band radar Astrium payload using GaN technology.  Built by Astrium and SSTL, an airborne (DC-3) demonstrator has been flown providing results that have been comparable to X band. The satellite is expected to be launched in 2014.

Conclusions

Despite the fiscally challenging environment, the importance of satellites in the military domain is going to continue to increase. Space is a sovereign asset, and a whole-of-government approach is needed to maintain both domestic capabilities and international operations. The fiscally constrained environment will result in more cooperation between nations on developing and sharing capabilities, and public private partnership (PPP) schemes will also see increasing use among other nations. The pooling of resources will be another feature in this fiscally challenging environment.

Technology and platform advances will serve as a catalyst for increased use of satellite platforms. Advances in technology have elevated the status of small satellites, and the utilization of COTS components is becoming more prevalent, especially as military satellite platforms share development with commercial ventures. Technology enhancements at the component and system level include GaAs-based triple junction solar cells, GaN-based power amplifiers, and the use of phased array antennas. Ka band will also form an increasingly staple part of the military satellite communications portfolio over the coming years.

This article was derived from the Strategy Analytics ADS service report, “Military Satellite Trends and Outlook”, which looks at the current status and future trends of military satellites based on presentations and discussions during the IQPC Military Satellites 2012 conference.