OTHER SPACE TOPICS
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SPACE DEBRIS

Orbital debris is an increasing problem. In the past little thought was given to the need to dispose of upper stages or the satellites themselves after serving their useful mission. But over time, with the increase of debris and occasional collisions, the concern is growing for how this problem may become worse. Add to that plans for mega satellite constellations and the risk or attacks on satellites during war and we've got the basis for worries that collisions will increase even to a point of where collisions will create more debris causing yet more collisions in a cascading event termed the Kessler Syndrome. Some will even go so far as to state that we might loose access to space and the end of the space age if something isn't done with the problem of space debris. Fortunately, these concerns are over-stated when one looks at the relevant data.

Actual collisions between satellites are pretty rare. The last satellite-to-satellite collision was in 2009 (ten years ago) when an active Iridium 33 smashed into the derelict Russian Kosmos-2251. There have been intentional intercepts of satellites using anti-satellite missiles causing a shower of debris. But countries tend to do this as a one-off event to demonstrate that they have that ability. In the case of India, they intercepted a satellite at a relatively low altitude such that most of the debris will re-enter the atmosphere.

It has long been common for satellites in the geosynchronous belts to be placed in a junk orbit after their useful life thereby freeing up the slot for another satellite to come in. It is also becoming standard practice for upper stages to perform an additional maneuver placing their trajectory to intercept Earth's atmosphere thereby taking them out of orbit.

As for the constellations, SpaceX is demonstrating the modern approach in which the satellites have the ability to maneuver and systems are being put in place whereby satellites can actively avoid collisions on an automated basis. This will go very far to ensure that more debris is not being created.

Overall, there still is a slow increase in the amount of orbital debris being produced but satellite operators are getting better at doing their part to slow that growth.

REMOVING ORBITAL DEBRIS
A number of space advocates argue for the need to actually remove orbital debris to prevent the Kessler Syndrome. There are various technical and legal ideas for how this could be done. Unfortunately, to date, the need to remove the debris has not been sufficiently compelling to result in anyone getting funded to actually develop a system to actively remove debris.

There have been in-space experiments using graspers, nets, and even harpoons. But these have only been demonstrations but nothing has moved on to ongoing operations. The reason for the lack of operations is probably because the risk and harm of collisions is sufficiently low such that it still largely remains a theoretical risk in the future. Some advocate that orbital debris could be viewed as a potential resource of high-quality metals. But again, this remains only as a theoretical resource and hasn't come close to actually being exploited.

THE WAY FORWARD
The Space Development Network believes that we are not near any crisis point when it comes to orbital debris. Certainly all upper stages should dispose of themselves shortly after launch and satellites should dispose of themselves near their end of life. We are very encouraged by the active avoidance approaches being used and we think that this will help greatly.

We do however think that systems need to be developed and implemented to remove those debris that have the largest cross-section and in orbits likely to cause a problem. We think that there are easier ways to get metals into LEO than the limited amount of orbital debris in various orbital planes.

Our greatest concern would be anti-satellite attacks producing a lot of orbital debris during a war. We think it more likely that, during war, that countries would first use other approaches to disable satellites than a kinetic attack. But we believe that any country causing a lot of orbital debris due to attacks should lose their right to use LEO after the war. This consequence could help countries think twice before conducting such attacks.

With a few strategies, orbital debris can be prevented from becoming a real problem.



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