By Bill Ostrove, Space Systems Analyst, Forecast International.
Small satellites are the next exciting technology in the space industry. Once the domain of universities, spacecraft under 100 kilograms have caught on in the commercial sector. At least eight private companies have announced plans to build huge networks of SmallSats to provide remote-sensing imagery data to customers.
Traditionally, imagery has been provided by large satellites, such as DigitalGlobe’s 2,800-kilogram WorldView-3 that launched in 2014. Companies like DigitalGlobe operate small networks of large satellites. DigitalGlobe, for example, operates a network of five satellites. Such companies make up for the small size of their networks with extremely capable spacecraft. The WorldView-3 can capture imagery with a resolution of 30 centimeters per pixel. But that capability is expensive: the WorldView-3 cost $300 million. Launches and insurance add to the expense.
SmallSat operators spin the equation around. They build large networks of small, cheap satellites. These small satellites only have a resolution of 1 meter per pixel, but what the satellites lack in capability, they make up for in numbers. The large numbers allow them to provide updated images of any spot on the globe daily – useful for monitoring farmland, natural resources, and economic activity.
The idea of using small satellites for remote-sensing purposes has been around for a while. Surrey Satellite Technology Ltd (SSTL) has been building and launching small satellites since 2002 with the launch of the first satellite in its Disaster-Monitoring Constellation (DMC). RapidEye (which was purchased by BlackBridge Geomatics Corp and eventually by Planet Labs) launched a network of 150-kilogram satellites in 2008. More recently, Skybox Imaging was purchased by Google to provide satellite imaging for the search-engine giant.
However, those satellites are quite a bit larger than the ones that the current crop of SmallSat operators are planning to build. New SmallSat operators will also manage dozens or even hundreds of satellites rather than the handful operated by SSTL and BlackBridge.
- Satellogic is following an incremental development approach to build a constellation of small imaging satellites, called BugSats. Three prototype BugSats have already been launched. Ultimately, the company plans to build a network of 300 satellites. However, it will begin operations with only 15 spacecraft. BugSats will operate in five spectral bands and will be connected via a mesh network that will not require ground stations to upload commands or download data. This will reduce costs and increase the speed of data delivery. Each BugSat will have a launch mass of about 22 kilograms.
- Planet Labs plans to deploy a network of 150 three-unit (3U) CubeSats in low-Earth orbit (LEO) to provide digital imagery of Earth’s surface. Planet Labs designed and is building its own satellites, which will have a launch mass of about 5 kilograms. The company uses some components that have not been specifically designed for the hardships of space operations; the sheer number of satellites included in the network will provide resiliency since a few satellites can fail without affecting the company’s ability to operate. Planet Labs is the leader in the number of satellites already deployed with 95.
- BlackSky Global plans to deploy 60 satellites into LEO. These satellites will orbit between 40 and 55 degrees (north and south) latitude. Each satellite will have a launch mass of about 50 kilograms. The larger size gives BlackSky the ability to sell images with 1-meter resolution. The satellites will also be large enough to accommodate a propulsion system, enabling them to stay in orbit for three years.
- Spire once launched spacecraft that carried electro-optical imaging equipment. Four of these were launched. However, the company later decided to build spacecraft that can provide meteorological data. Spire’s Lemur-1, a 3U CubeSat, is a prototype of the spacecraft that the company says will eventually form a 50-satellite constellation. Each satellite will have a launch mass of 4 kilograms.
- NorStar Space Data is currently working with NovaWurks to develop specifications for a 40-satellite network of SmallSats. Unlike other SmallSat operators, NorStar’s network of satellites, designated NorthStar, will include sensors to monitor space as well as Earth. The company believes that this ability will expand its potential customer base, with militaries interested in space situational-awareness data.
- GeoOptics’ CICERO constellation is expected to become operational in 2016 with the deployment of six satellites. CICERO satellites will be equipped with GPS and Galileo navigation satellite radio occultation sensors. The company says that its constellation will consist of a gradually increasing number of satellites. The constellation will start with six in 2016, increase to 12 in 2017, and finally increase to 24 in 2018.
- UrtheCast plans to build a network of eight optical and eight synthetic aperture radar (SAR) satellites flying in different orbital planes. Each plane will comprise four pairs of satellites, and each pair will consist of an optical satellite and a SAR satellite operating in X-band and L-band. The satellites will include onboard processing and cross-cueing capability.
- PlanetiQ will deploy a fleet of 12 6U CubeSats equipped with GPS radio occultation sensors, each with a launch mass of 20 kilograms. The satellites will measure the distortion of GPS and other navigation signals as they pass through the atmosphere. The measurements will provide soundings of the atmosphere that can be included in weather forecast models. Future satellites may include additional instruments.