Commentary | Another View on Cubesats and Debris
In response to recent articles regarding cubesats and space debris [“Cubesat Boom, Unheeded Debris Rules Fueling Dangerous Orbital Congestion,” Oct. 6, page 1, and “Debris Cloud Gathers Over Cubesat Party,” Editorial, Oct. 13, page 18], I would like to offer some input from a stakeholder in the cubesat community in order to provide balance and continue this important discussion on the sustainable use of the space environment.
ISIS — Innovative Solutions In Space has been active in the cubesat sector for nearly a decade, and the company has been involved in debris mitigation technology development, such as drag sails and deorbit motors, since 2007. Through our own missions and our ISILaunch Services, we are subject to various aspects of space debris; the sustained use of space is a daily aspect of our activities, and as such is a growing concern.
From the active debris removal studies we have been involved in, the key contributors to the debris problem were always large objects (defunct upper stages and large satellites) that still carry unused fuel with associated fragmentation risk. These objects have a large acceleration effect on the debris growth and are the prime targets for debris removal missions to curb the growing collision risk in low Earth orbit.
As cubesats are by definition not large (they typically have a cross-section that is a factor 100 smaller than a 250-kilogram spacecraft) and usually do not carry propulsion, pressure tanks or pyro-devices, a cubesat is in fact the exact opposite of the objects that are considered to be the biggest threat: They are small, are hard to be hit and have the lowest probability of exploding and thus creating many small fragments when compared with larger space objects.
The fact that cubesats are growing in popularity (although I would not go as far as to call the growth rate “dizzying”) and being used in larger numbers does not automatically translate into a higher collision risk. Smaller probability of being hit means a conjunction is less likely to result in an actual collision, and smaller impact when a collision occurs may actually result in a lower risk overall despite the growth rate of cubesats in use.
This does not mean that cubesats should not strive to comply with the guidelines. They ought to do so and in fact typically do (albeit with the guidance of their launch brokers). Many cubesat developers work on technical solutions such as drag enhancement devices and deorbit propulsion modules as well as platforms for active debris removal demonstrators. In addition, launch service providers that serve the cubesat community are looking for ways to drop off cubesats in “debris-safe” orbits.
In conclusion, it is our belief that the cubesat community is taking the concerns of space debris to heart and is largely supportive of adherence to the guidelines by everyone in the space sector. However, cubesats are a small part of a big problem where the whole sector needs to take its responsibility.
Due to the short development cycles, the cubesat community is addressing debris issues faster and more often than traditional space programs and can provide a meaningful contribution in debris mitigation. New debris mitigation techniques and launch systems able to deliver satellites to “debris-safe” orbits are as valuable for cubesats as for other low Earth orbit systems, and cubesats even play a key role to quickly demonstrate potential solutions for debris mitigation and active debris removal.
However, the small-satellites sector is characterized by many small players compared with other segments in the space sector (with only few big players) and can and should organize itself better to address the orbital debris issue as a community.
Jeroen Rotteveel is chief executive of ISIS — Innovative Solutions In Space, a Dutch company focused on small-satellite projects and applications.