18-02-2022 | By Robin Mitchell
Recently, a geomagnetic storm has caused the Earth’s atmosphere to expand and increase the drag on spacecraft in low-earth orbit and may have sentenced 40 Starlink satellites to death. What challenges does space have on electronics, what caused the recent Geostorm, and how can engineers prepare for such incidences?
Electronics are highly advanced engineered materials designed to manipulate current, and yet, these inanimate circuits appear to perform best in environments also ideal for people. Circuits at 21˚C at one atmosphere of pressure seem to be some of the happiest around, while those going beyond 70˚C start to deteriorate, those in low pressures may crack, and those at freezing cold temperatures can make some devices unresponsive (such as LCDs).
Despite its mostly empty nature, space is one of the harshest environments for electronics and requires careful planning for even the simplest circuits. For one, the vacuum of space means that there is no way for devices to remove heat through the convection of air, and thus removing heat requires the use of radiated heat. Secondly, electronics not pointed towards the sun will experience nearly zero temperatures that break circuits. Thirdly, the lack of a magnetic shield provided by Earth means that any circuit in space is exposed to the sun’s full power, which includes large amounts of high-energy particles such as protons and electrons.
Solving these challenges often requires large amounts of supporting hardware such as heaters and reaction wheels to ensure that the satellite rotates (providing uniform heat) and shields against radiation. Of course, no amount of shielding or hardware will protect a satellite from debris that can travel up to 11km/s (relative).
There is no doubt that Elon Musk has made outrageous claims on technology such as Hyperloop, Boring Tunnel, and Tesla robots, but credit must always be given when due, and his Starlink project is one of his best. The idea of having many thousands of satellites in low-earth orbit to provide satellite internet no matter where one is would not only free many from unreliable internet services but could even provide infrastructure to those in the most remote of places.
Each Starlink satellite is designed to extremely high standards for use in space, and each one is anticipated to cost about $250,000. But, no matter how expensive each satellite is or how brilliant the engineers behind the satellites are, if nature decides to kick up a fuss, then virtually nothing can be done to protect the satellites.
Recently, a Geostorm experienced by Earth from increased solar activity excited the atmosphere enough that it expanded well into the orbital path of a recent Starlink launch carrying 49 satellites. This atmosphere expansion resulted in 50% extra drag on the satellite payload, which has unexpectedly caused 40 to not reach their required orbits.
Fortunately, the now de-orbiting satellites pose no risk of collision with any infrastructure already in orbit and will burn up safely in the atmosphere with time. But even though the engineers used all tools possible (including pointing the satellites towards the storm to make their cross-sectional areas as small as possible), onboard GPS controllers indicated significant drag and reduction in velocity.
Unfortunately, not everything can be mitigated against, and something like a Geostorm is what insurance companies would call “an act of god”. However, it is for these reasons why insurance companies exist, and thus the only real mitigation an engineer can do is to get such insurance; a successful flight or your money back”.
The use of deep-space sensors and storm monitors could be a future solution to mitigating against such storms as radio signals travel faster than charged particles. For comparison, some of the fastest coronal mass ejections travel at a speed of 3000kms while the speed of light is 300,000k/s. This means that by the time a powerful CME reaches Earth, we would have had 13 hours to prepare.
Space is dangerous, and even though we are protected by our magnetosphere, cosmic rays and solar storms present major challenges to future infrastructure. Considering that modern life is dependent on technology, maybe we should start looking at better ways to protect ourselves?