Measuring approximately 10 centimeters on a side and weighing around 1 kilogram, cubesats have gained popularity among small companies, universities and emerging countries, enabling them to break into space and the communication industry. From the introduction of the cubesat format to July 2015, 231 of the small satellites were launched and another 44 were lost due to launch failures.
As cubesats’ use continues to grow, debris mitigation and avoidance regulations are also becoming progressively restrictive in order to avoid a degradation of space use among space industry operators.
Because cubesats lack an onboard propulsion system, it is hard to perform a calculated re-entry operation at the end-of-life, causing most cubesats to violate international guidelines on appropriate deorbiting maneuvers. Matt Desch, chief executive of Iridium Communications Inc., said, “The proliferation of cubesats… present[s] new, potential problems” and they “are creating a new challenge requiring particular attention.”
Best practices formulated by the Inter-Agency Space Debris Coordination Committee are being implemented at a national level in new licensing, satellite manufacturing, and insurance contracts.
In some cases, national legislation further regulates debris prevention. French law requires all national and international operators active on its territory (including French Guiana) to put all end-of-life satellites orbiting within 2,000 kilometers in a controlled re-entry if the probability of hitting people and assets on ground is greater than 10-4 (which, of course, it is not the case of such small satellites).
In most cases, however, regulations and best practices require an end-of-life maneuver leading to re-entry within 25 years, to the detriment of future cubesat missions, which are often unable to comply with these requirements and can even take up to hundreds of years to deorbit.
In general, the density of debris in the operational orbits would greatly increase if decommissioned satellites were not properly removed at the end of life, with several negative results:
- Satellite service reliability: An impact would destroy an operational satellite and pose a risk to other assets in the same orbit. Debris avoidance will require maneuvering away from the designed orbital position at an increasing rate and with little warning time. This is clearly a cost for the other operators.
- Operational costs: Satellite operators will need to operate redundant satellites, performing collision avoidance maneuvers that will consume station-keeping fuel. Moreover, the increasing number of spent satellites and fragments will require continuous monitoring;
- Insurance costs: Insurance premiums will be negatively impacted by the increasing risk of operations in such orbits.
Decommissioning does not have to be expensive, and there are solutions applicable to nanosatellites that can stabilize the space debris environment at an acceptable safe level, especially in regions with higher densities where risk of collision is particularly high. A smart decommissioning system could remove satellites and launcher’s stages in a safe, quick and controlled manner while complying with all regulations and space debris mitigation guidelines, providing a direct controlled re-entry into the atmosphere within hours if necessary.
If cubesats are to increase in popularity, there should be a collective responsibility to guarantee sustainable use of space from all operators. The possibility of progressive space exploration can be nurtured without necessarily having a negative impact on the space environment. We need to push for smart technology to avoid problems that have affected our planet at the expense of society and its development.
Luca Rossettini is chief executive and co-founder of D-Orbit, an Italian startup targeting the space debris mitigation market.