SSC11-III-1 25 Years of Small Satellites Siegfried W. Janson The Aerospace Corporation Mail Stop M2/241, P.O. Box 92957, Los Angeles, CA 90009-2957; 310.379.7060 [email protected] ABSTRACT Twenty-five years ago in 1986, 25 microsatellites were launched into orbit; 24 were military communications satellites lofted by the former Soviet Union as part of a communications constellation. No active nanosatellites or picosatellites were launched that year. Last year (2010), 4 microsatellites, 15 nanosatellites, and 3 picosatellites were launched. Small spacecraft have gotten smaller, and they are being used for more than just communications. Advances in micro/nanoelectronics, microelectromechanical systems, solar cell technologies, global positioning systems, and the Internet have allowed small groups of individuals to design, build, and fly ever-smaller satellites with ever-increasing capabilities. In parallel, small satellite containment and deployment systems like the P-POD for CubeSats have been developed to minimize potential negative impacts on the host launch vehicle and primary payload, thus increasing the number of available launch opportunities. This work discusses small satellite launch trends, technology trends, satellite trends, and small satellite missions. 1.0 SMALL SATELLITES 25 YEARS AGO (1986) between 1970 and 1993. About 30 operational Like most years, 1986 had its ups and downs. Major satellites, at any given time, gave fairly complete Earth coverage using randomly distributed satellites within space-related events included Voyager 2 making its individual orbital planes. The Strela-1M satellites were first encounter with Uranus, the painful loss of seven preceded by Strela-1 experimental microsatellites astronauts onboard the U.S. Space Shuttle Challenger, launched during 1964 and 1965, and later replaced by Halley’s comet reaching perihelion, and the former Soviet Union launching the Mir space station. For heavier, non-microsatellite class, Strela-2M and Strela- small satellite enthusiasts, 1986 saw the launch of 25 3M communications satellites. microsatellites (10 to 100-kg mass), no nanosatellites (1 The remaining microsatellite launched in 1986 was the to 10-kg mass), and no picosatellites (0.1 to 1-kg mass). 50-kg mass Fuji-Oscar 12 amateur radio satellite. It More importantly, these terms didn’t even exist; 200-kg was the 12th Orbiting Satellite Carrying Amateur Radio and lighter spacecraft were called small satellites or (Oscar) and was put into a 1497 x 1479-km, 50o lightsats. inclination orbit by a Japanese H-1 launch vehicle.2 It operated over three years and stopped due to premature Twenty four of the 25 microsatellites launched in 1986 were 61-kg mass Strela-1M spacecraft built and flown battery failure. by the former Soviet Union. Strela (Russian for 2.0 HISTORICAL TRENDS ―arrow‖) spacecraft were designed to provide medium- range, record-and-forward communications using low Figure 1 shows yearly launch rates for microsatellites, Earth orbit (LEO).1 Starting in 1970, operational nanosatellites, and picosatellites from 1955 through Strela-1M spacecraft were launched on Kosmos-3M 2010. The upper chart shows microsatellite launches boosters, eight at a time, into ~1500-km altitude orbits and is color-coded to indicate Strela-1 and -1M launch at 74o inclination about twice a year. They had an rates separately from other microsatellites. This chart expected operational lifetime of about two years (GEO shows an initial growth spurt lasting about 10 years, communications satellites now have 7-to-15 year followed by a ~10-year decline in non-Strela expected lifetimes) and had to be replaced on that same microsatellite launches. A marked dearth of non-Strela time scale; 360 Strela-1M spacecraft were launched microsatellites occurs from roughly 1977 through 1987; the ―Small Satellite Doldrums.‖ Janson 1 25th Annual AIAA/USU Conference on Small Satellites Figure 1. Launch History of Microsatellites, Nanosatellites, and Picosatellites. Janson 2 25th Annual AIAA/USU Conference on Small Satellites The middle chart in Figure 1 shows yearly launch rates sophisticated satellites to promote space science and for nanosatellites. This chart excludes about 600 Romb engineering in education. These box-shaped spacecraft subsatellites that were deployed by the former Soviet used several different microprocessors to perform Union, and later Russia, between 1976 and 1995 from command and control, digital communications, power Taifun-2 and Taifun-3 spacecraft.3 Cosmos 965, for system control, etc. The term ―microsatellite‖ seemed example, was a Taifun-2 satellite with a total mass of appropriate for these microelectronics-enabled small 550-kg that deployed 25 Romb radar calibration spacecraft, and CSER at the University of Surrey can be subsatellites. Although specific data on the deployed credited with creating the terms ―microsatellite‖ and Romb subsatellites are hard to obtain, they were most ―nanosatellite‖ in 1990.5 likely nanosatellites based on the initial Taifun-2 spacecraft mass and number of Romb spacecraft 2.1 Small Satellites Return: 1987 to 1999 deployed. The Romb subsatellites are not included in ―The Small Satellite Doldrums‖ ended in 1987. Fig. 1 because of uncertainty in their mass, the high Interestingly, two new, pivotal, small satellite average launch rate of these spacecraft (about 32 a year conferences were held that year. The first one was over 19 years of launches) that totally eclipsed other sponsored by the American Institute of Aeronautics and nanosatellite launch rates, and their lack of traditional Astronautics (AIAA) and the Defense Advanced spacecraft subsystems like power conditioning, Research Agency (DARPA). This Meeting on communications, etc. Lightweight Satellite Systems occurred August 4-6 at the Naval Postgraduate School in Monterey, California The bottom chart in Figure 1 shows yearly launch rates 6 (USA). DARPA was investing in small satellites for picosatellites. At the start of 2000, only 10 called LIGHTSATS, plus associated launchers and picosatellites had been launched, and 7 of these were ground-based equipment, with a proposed 5-year, passive, inert satellites for measurement of atmospheric billion-dollar effort starting in 1987.7 This first density or radar calibration. These passive LIGHTSAT meeting had 47 presentations by military, picosatellites were launched in 1971, 1994, and 1995. civil (e.g., NASA), and commercial, experts. No active picosatellites were launched from 1965 Universities were associated with only 3 presentations. through 1999; over three decades of non-activity. DARPA continued with its LIGHTSAT program and A large number of small satellites were launched launched two 66-kg mass Multiple Access throughout the 1960’s to obtain space environment Communications satellites (MACSATs) in 1990, and data, flight test various technologies, and provide seven 22-kg mass ―MICROSATS‖ in 1991.8,9 The operational communications. Satellites grew heavier MICROSATS had microprocessor-controlled digital over time as satellite expectation levels, and launch communications payloads. In addition, The U.S. Navy vehicle payload capacity to low Earth orbit, increased. launched the 68-kg mass Small Experimental Microsatellites, nanosatellites, and picosatellites were Communications Satellite (SECS) in April of 1990, and essentially replaced by heaver, much more capable, the U.S. Air Force launched the 95-kg Radar spacecraft over time. This trend resulted in the ―Small Calibration (RADCAL) microsatellite in June, 1993. Satellite Doldrums.‖ Technology and economics U.S. military microsatellites were returning to ultimately reversed that trend starting in 1987. operational use. It is interesting that the ―Small Satellite Doldrums‖ did The second small satellite conference in 1987 had not seem to impact experimental and educational somewhat larger academic participation. The first spacecraft launched by the Radio Amateur Satellite annual USU Conference on Small Satellites was held Corporation (AMSAT). AMSAT members did not 24 years ago on October 7-9, in Logan, Utah. want, or could not afford, communications capabilities Technical papers were presented by experts from provided by large satellites. They made do with small AMSAT, NASA-Goddard Space Flight Center, the U.S. satellites typically in the microsatellite mass range. By Army, the Swedish Space Corporation, Globesat, The 1978, AMSAT had launched 7 educational and amateur Johns Hopkins University Applied Physics Laboratory, radio satellites (OSCAR 1 to OSCAR 7) with masses Boeing, Hercules Aerospace Company, Weber State ranging from 4.5 to 29-kg.4 By 1987, they launched 5 College, Morton Thiokol, L’Garde, The University of more satellites with masses ranging from 50 to 91-kg. Surrey, Intraspace Corporation, Ball Aerospace, the Two of these spacecraft, OSCAR-9 (also called UoSAT University of Colorado, the Naval Postgraduate School, 1) and OSCAR-11 (also known as UoSAT 2), were Utah State University, the U.S. Air Force, Expanding built by the Centre for Satellite Engineering Research Horizons Safety Consulting Services, and NASA-Ames (CSER) at the University of Surrey, in the U.K. They 10 Research Center. AMSAT provided several papers, were part of a program to develop low-cost Janson 3 25th Annual AIAA/USU Conference on Small Satellites and would continue to play an important role in small 2.2 Small and Smaller: 2000 to 2010 satellite development. On January 27, 2000, an Orbital Sciences Minotaur rocket put JAWSAT into