Are cubesats a nuisance to space situational awareness efforts?
MAUI, Hawaii – Small satellites and cubesats should not be viewed as a major contributor to congestion or in creating space debris in low earth orbit, at least based on recent history, a panel of experts here said Sept. 23.
“We need to change our attitude about cubesats. They are not a nuisance,” Bhavya Lal, a research staff member at the Institute of Defense Analyses’ Science and Technology Policy Institute, said during a panel discussion. “[They are] a very important part of our satellite ecosystem.”
Speaking at the AMOS conference, Lal said all but one cubesat has been tracked by the Air Force’s Joint Space Operations Center and 18th Space Control Squadron, which issues collision warning messages. Because of that tracking, the Air Force has been able to ensure cubesats do not crash into other satellites and create unwanted debris.
Lal said Air Force data shows cubesats have forced other satellites to maneuver and avoid a collision three times this year, twice in 2015 and three times in 2014. For perspective, U.S. Strategic Command has said all operators performed a total 121 maneuvers in 2014 to avoid potential collisions.
The panel marked one of the first large-scale discussions between two pockets of the space community that often have little overlap: the space situational awareness crowd and the small satellite proponents.
Cubesats have been derisively – and commonly – referred to as “debris sats” by some operators in the space community. Those operators view cubesats as a danger because many of them are so small they do not have propulsion systems and depend on atmospheric drag to pull them toward re-entry within 25 years, which is the government standard. They are also difficult to initially track, especially when they are launched in batches from the International Space Station.
In 2014, Hugh Lewis, a professor at the University of South Hampton, said in a paper that at that time up to two-thirds of all cubesats launched are predicted to remain on-orbit for more than 25 years. That’s about on par or slightly above the rates for all spacecraft. Lewis also suggested cubesat operators follow sustainability practices and debris mitigation activities.
“Throw the rules at us,” said Jordi Puig-Suari, a professor at California Polytechnic Institute and one of the founders of the cubesat. “We are not in crisis mode. The professionals are following the rules. The amateurs … will try.”
Many cubesats are built by non-traditional space operators, such as universities and even high schools.
The Air Force, for example, sends cubesat operators a booklet of recommended behaviors for interacting with the Joint Space Operations Center to improve tracking efforts, said Diana McKissock, who works for the JSpOC.
Puig-Suari noted in a slide on congestion that about 417 cubesats have launched this year. On the same slide, he pointed out that the Air Force’s Defense Meteorological Satellite Program has created about 346 pieces of debris.