Small Satellite Technology: Gains Open Space to More Players
Some interesting parallels exist in the evolution of the computer and satellite industries. Both initially were dominated by big metal, with mainframes housing the financial records of large corporations and large satellites ruling the sky. But mainframes lost their grip as they proved difficult to program for advanced applications or simply were too expensive for anything other than keeping massive databases. Could the same happen in the satellite field?
Big satellites come with big price tags, which effectively limits the type of organization that can purchase them to governments, militaries, and satellite service providers, but technological advancements are leading to a generation of small satellites that can provide more and more advanced services and open up space to a new generation of users. It was a host of small, nimble companies that prospered after rolling out minicomputers dedicated to running specialized applications, opening the door for the personal computers and servers that came later and the computer market mushroomed. Now the stratification of the satellite industry is picking up speed and, as happened in the computer industry 30 years ago, a new breed of companies are introducing new satellites for specialized applications.
Less is More
There is not a conical definition of what fits into the category of small satellite, but generally it is regarded as any spacecraft with a mass of less than 1,000 kilograms. A taxonomy of sorts has arisen within the small satellite community to help provide some granularity. Cubesats, sometimes called picosats, are limited to 10 centimeters per edge and a total mass of 1 kilogram, while satellites ranging from 25 kilograms to 30 kilograms often are referred to as nanosats. The top end of the small satellite scale generally ends at 1,000 kilograms.
The advent of these smaller spacecraft has broadened the market, says Jeff Foust, senior analyst for Futron Corp. "The market has really expanded over the last 20 years. As costs have come down, satellites are being purchased by a number of diverse organizations. The major uses for small satellites are remote imaging, science, technology demonstration platforms for new space hardware and military or defense purposes. A number of countries have leveraged the availability and cost effectiveness of small satellites to launch national space programs. Non-traditional spacefaring nations now have a way to get their foot in the door when it comes to space."
Historically, small satellites have been used as technology demonstrators, but that is changing, says Todd Mosher, director of advanced systems at MicroSat Systems Inc., wholly owned subsidiary of Sierra Nevada Corp. "A lot of eyes have been opened regarding the capabilities of small satellites," he says, citing a contract Sierra Nevada signed in May to provide 18 small satellites to Orbcomm Inc. for the companies second-generation constellation. The Orbcomm Generation 2 satellites will be based on MicroSat’s work on NASA’s TacSat-2 mission. Each satellite will cost $6.3 million dollars to build and will be equipped with an enhanced communications payload designed to increase subscriber capacity by up to 12 times over the current Orbcomm satellites. The new constellation is expected to be in orbit by 2011. Mosher notes that the rest of the world has embraced small satellites for many years and the United States now is catching up. "The reality is that budget constraints made many countries take a make-do approach and the results were small satellites. Countries not traditionally associated with space now have a way to participate," he says.
"There is a recognition that [small satellites are] not an alternative market to the more traditional large, highly-complex and multifunctional satellites, but it is really complementary to that market, particularly for emerging technology such as demonstrators and early missions."
— Paynter, Astrium
A good example of where small satellites are making a commercial and civil impact is in the imagery arena, and a prime example is the group of countries which jointly own and operate the Disaster Monitoring Constellation (DMC). Algeria, China, Nigeria, the United Kingdom and Spain each own imagery satellites that can collect imagery with a ground resolution of 32 meters covering a 600-by-600-kilometer swath of Earth. The satellites, each weighing about 90 kilograms, follow the same orbital path so new images of the same spot on the planet are updated multiple times per day. By operating the group of satellites as a constellation, the cost for each supporting member was cut dramatically. While the images primarily are used by the countries that own the satellites, the constellation also provides images to disaster relief organizations, and the imagery has been used for relief efforts following the Indian Ocean Tsunami, Hurricane Katrina and the recent earthquake in China.
The imaging spacecraft were developed by Surrey Satellite Technology Limited (SSTL), which has had 27 of its spacecraft placed in orbit since the company spun out of the University of Surrey in 1981. Paul Brooks, SSTL’s vice president of sales, says the company’s business plan developed as it noticed many traditional satellite programs spiraling out of control in terms of cost. "When a satellite is being designed the owners look for ways to extend its mission. The designers then put more payloads on the spacecraft to deliver more value, but then the cost goes up," he says. "This creates more financial risk which then requires greater assurance that everything will work as planned. The greater assurance lengthens the lead time. You ultimately end up with very large missions and by the time the payload is launched, it is out of date. We noticed that this pattern repeated itself in the satellite industry and, unlike other technology-driven markets, there weren’t huge increases in performance and large decreases in cost. We believe that Moore’s Law should apply to spacecraft as well," he says.
"Because of our quick pace — roughly one launch per year since the company formed — we have a high refresh rate. This allows SSTL to utilize the newest technology in our satellites," says Brooks. "We have a large heritage baseline to draw from, and we never have to start anything from scratch. Seventy to 80 percent of all of our avionics will work on any of our satellites, so we can focus on what is new for a particular mission. Plus we are very highly integrated. We build everything from the boards to the sensors and then do the integration." This approach is reflected in a new generation of imagery spacecraft that will begin joining the DMC constellation later this year. The satellites will carry sharper cameras that collect images with a resolution of 22 meters. "This generation of SSTL DMC satellites will have 10 times the capability of the first generation at the same price only five years after the first generation was launched," says Brooks. "This typifies SSTL’s continuous and rapid development of capability."
This success has attracted the attention of customers — 14 spacecraft are under construction at SSTL — as well as the attention of satellite manufacturer EADS Astrium, which announced in April that it had acquired control of SSTL from the University of Surrey. "SSTL has a substantially complementary product range to ours, which means it enhances our product range as an overall group of companies," says Colin Paynter, CEO of Astrium in the United Kingdom. "… SSTL has a very different approach to the economics of space, which is particularly attractive to us. They build partnerships with what I call emerging nations, those countries who are just getting the idea of having a small satellite or with the universities in those countries getting some space research under way. SSTL has a really good model of working with those countries and delivering small satellites to them. That is a very different approach to Astrium, which has much more commercial, large institutional and major government customers."
Astrium sees small satellites performing complementary roles to larger satellites and also sees today’s small satellite customers becoming buyers of larger satellites in the future. "There is a recognition that small satellites will play an important part in some markets," says Paynter. "There will still be a strong demand for large telecoms satellites and multi-sensor satellites, but small microsatellites can be useful in offering a range of technology demonstrators. They can also add discrete functionality to certain missions by sitting alongside larger satellites. In certain areas, where the functionality could be changing over a three-to-five-year period, a small low-cost platform offers advantages. There is a recognition that it is not an alternative market to the more traditional large, highly-complex and multifunctional satellites, but it is really complementary to that market, particularly for emerging technology such as demonstrators and early missions."
Access to Space
While the cost to develop and build small payloads is attractive to many different disciplines, placing the finished spacecraft into orbit remains quite expensive; however, there are positive developments which will widen the door to space a bit further.
Space Exploration Technologies Corp.(SpaceX) is working out the kinks in its Falcon launch vehicles. Elon Musk, the driving force behind the company, has invested more than $100 million of his own money for the purpose of driving down the cost to access space. The key to this is the Merlin engine, which will power the company’s Falcon 1 and Falcon 9 rockets. "No one has figured out how to go from the Earth to orbit with a single stage rocket," says Larry Williams, SpaceX’s vice president of strategic relations. "To increase reliability you need to minimize the number of engines and the number of stages. This minimizes the potential for problems with stage separation and propulsion."
The Falcon 1 has two stages; the first utilizes a Merlin engine, while the second stage harnesses the power of a Kestrel engine. The first attempt to launch a Falcon 1 in March 2006 ended in failure less than a minute after ignition. The second attempt in March 2007 failed to reach orbit, but the company labeled the effort a success since "this test has flight proven 95-plus percent of the Falcon 1 systems," Musk said after the launch." SpaceX has contracted 14 launches, and conducted a full launch dress rehearsal and hold down firing of the Falcon 1 Flight 3 vehicle in June, the first launch pad firing of the Merlin 1 engine, in advance of a mission scheduled to take place between late July and early September. The Falcon 1 is scheduled to place the Trailblazer satellite in orbit for the Jumpstart Program of the U.S. Department of Defense’s Operationally Responsive Space Office. Secondary payloads include an adapter system developed by the government of Malaysia that holds two small NASA satellites.
Orbital Sciences, which has been a force in the small satellite market for several decades, offers clients multiple launch options, including the Pegasus, Minotaur and Taurus launch vehicles. The Pegasus rocket is air-launched from a retrofitted L-1011 aircraft and can loft satellites with a mass of up to 450 kilograms into orbit. The ground-launched Taurus is for spacecraft weighing up to 1,350 kilograms. The Minotaur launch vehicle comes is multiple variants, each using decommissioned rocket motors from Minuteman or Peacekeeper intercontinental ballistic missiles (ICBM). Due to the classified nature of the military rockets, only U.S. government payloads may be launched on Minotaur rockets.
Russia also has turned to decommissioned ICBMs as launch vehicles. The Dnepr rocket, designated by NATO during the Cold War as the SS-18 Satan, entered the commercial market in 1999. The liquid-fueled, three-stage rocket has built a successful track record for launching small satellites. The Indian Space Research Organization developed the Polar Satellite Launch Vehicle (PSLV) to lift India’s remote sensing satellites into solar orbit, but the agency now provides a viable commercial option for launching small satellites into low-Earth orbit.
But until launch costs are lowered dramatically, small satellites most likely will continue to hitch rides into space with a larger spacecraft as a secondary payload. Historically, secondary payloads have been viewed with intense scrutiny, as the onus was placed on the secondary payload to prove that it would not interfere with the launch vehicle or primary payload. This created an added expense to small satellite operators seeking a ride to orbit.
The Evolved Expendable Launch Vehicle Secondary Payload Adapter (ESPA) is an aluminum ring which allows up to six small satellites to be carried into orbit as secondary payloads aboard either Boeing’s Delta 4 or Lockheed Martin’s Atlas 5 rockets. Developed by the U.S. Air Force, the ESPA ring can carry spacecraft weighing up to 180 kilograms each and has introduced a standardized methodology to launching secondary payloads. In March 2007, an Atlas 5 rocket operated by the United Launch Alliance used the ring to place four satellites into orbit, including small satellites for the U.S. Air Force Academy and the U.S. Naval Academy.
Facing the problem of getting student-built payloads into orbit, California Polytechnic State University (Cal Poly) teamed with Stanford University to find another way to help alleviate fears of launching cubesats. The collaboration led to the development of the Poly Picosatellite Orbital Deployer, an aluminum enclosure which houses up to three cubesats. If the satellites were to break up during launch they would be contained in order not to dame the primary payload. Launch costs for using the P-POD ranges from $40,000 to $80,000 depending on the type of launch vehicle.
There are three major areas of growth for small satellites: science and technology, Earth monitoring, and next-generation communications, says Stan Kennedy, vice president for Advanced Systems for AeroAstro. The high cost of satellites, and getting them into orbit have historically limited satellite ownership to those with deep pockets, however, those days are over. Small satellites, combined with cost effective launch vehicles, are enabling technologies which will broaden the space market.