By Tobias Bolli, Junior Project Manager Academic Relations
Although space is often described as a huge expanse of nothingness – only 0.0000000000000000000042 percent of the universe actually contains matter – things start to look different when we focus in on what’s directly above us. Earth’s orbit is filled with satellites ranging from the size of a parcel to that of a school bus. Together these satellites provide us with such useful things as GPS, telecommunication and weather forecasts. In addition, they are joined by countless objects, which serve no purpose at all. In fact, there are more «retired» satellites than there are operational ones, currently about 3000 of a total 5000. This so-called space junk makes orbits increasingly overcrowded and poses a serious risk to past, present and future missions (for an overview of all known objects in earth’s orbit, click here).
Prof. Jean-Paul Kneib, Director of EPFL Space Center (eSpace) dedicated his presentation – an event organized in cooperation with EPFL Alumni Shanghai Chapter – to this long-neglected phenomenon. He pointed out that space debris consists of more than a million objects larger than one centimeter and just about 35´000 objects over 10 centimeters. These objects aren’t just staying in space but are dashing around at enormous speeds, often multiple times faster than a rifle bullet. The fastest debris reach up to 7 kilometers per second - keeping in mind that the velocity has to be squared to calculate kinetic energy this makes for impressive numbers.
Due to their enormous speed even small object can have considerable destructive power in space…
Prof. Kneib reminded the audience that the International Space Station has to take this fact into account and dodge space junk almost on a weekly basis. Other satellites in space aren’t so lucky and can’t rely on a propulsion system to get them out of harm’s way. Prof. Kneib mentioned a solar panel, which all of a sudden went missing after a collision. Such collisions lead to even more space junk, which in turn increase the likelihood of more collisions – a downward spiral, which is hard to escape. Things become even more alarming, when one considers the huge uptick in objects flying to space. This is in no small part due to private companies such as Blue Origin (a hobby horse of Jeff Bezos, the richest man on earth) and SpaceX (a passion project by yet another wealthy individual, Elon Musk). What in the past was used once and then thrown away – the rocket launcher – can now deliver multiple payloads to space. This recent revolution in reusability has lead to cheaper access to space, and, in turn, to an exponential increase in launches. This may be an exciting thing on the one hand, however it only accentuates the already looming space debris crisis. Prof. Kneib highlighted the Starlink project by Musk, which in the coming decades wants to populate space with up to 42'000 additional satellites, which is more than 20 times the amount of functional satellites currently in space.
SpaceX releasing a batch of 60 satellites into low earth orbit as part of its Starlink project. Many experts worry that it will further escalate the space debris crisis.
Having thus laid out the problem (and succeeded in making the audience worried), Prof. Kneib continued to do what few have done so far: offer actual solutions. He presented the CleanSpace One project, a Swiss initiative which aims to start tackling space junk, and actively removing it from space. Even though only a handful of people have been involved in the project, CleanSpace One was recently selected by the European Space Agency (ESA) to launch a proof-of-concept mission. The idea is to send out a washing machine-sized satellite, which is able to grab a satellite (in this case the first Swiss satellite launched into space ten years ago) to subsequently take a deep dive and burn up together with its “cargo” in the earth´s atmosphere. What may seem a rather crude approach is nevertheless a necessary one. Simply put, “nobody has done it before” as Prof. Kneib pointed out, and somebody has to take a first step in the right direction. Moreover, Prof. Kneib talked about future iterations, which would be able to not only remove a single satellite but go back and forth between orbits and deliver multiple pieces of space junk to their fiery death.
The basic idea of ClearSpace One is to go up, grab stuff and then to go down again. What sounds easy, is a very challenging endeavor in practice.
Initiatives like this are not enough, however, there has to be strict regulation as well to prevent the situation from worsening. Prof. Kneib stressed that efforts to contain the crisis have been ineffective thus far. Space agencies merely recommend that a satellite´s lifespan be limited to 25 years, but companies have been turning a blind eye to that recommendation – knowing full well, that they wouldn´t suffer much in terms of consequences for their behavior. Thus, international and actually binding regulations are needed to discourage what economists call negative externalities – basically the outsourcing of negative effects to a third party. Since people tend to be mainly concerned with their own benefit, and not so much with the well-being of others, negative externalities are bound to occur everywhere, even in space. In order to rein them in, Prof. Kneib suggested enforced long-term planning regarding the use of our shrinking space in space. He concluded: “Sustainability is the new way to think, and it is the only way to think.”
The audience of around 30 people was very much captivated by Prof. Kneib´s presentation.
During the lively Q&A session Prof. Kneib revisited the immense destructive power of even small pieces of space junk. Given a head-on collision, an object measuring no more than one centimeter can incapacitate a satellite worth billions of dollars. Moreover, Prof. Kneib reiterated how little regulation exists pertaining to space, pointing out that sometimes companies don´t even wait for an official flight approval but just proceed to launch their rocket anyway.
After the presentation, participants had the opportunity to network and treat themselves to an assortment of delicious finger food. We would like to thank Prof. Kneib for his inspiring lecture, and Mr. Ren Zhanbing, Head of EPFL Alumni Shanghai Chapter for supporting the event.