Herbert O. Funsten is a space scientist and leader of the Intelligence and Space Research division at Los Alamos National Laboratory in New Mexico. He contributed this article to Space.com's Expert Voices: Op-Ed & Insights.
Since the dawn of the space age in 1957, 80 countries and intergovernmental organizations have launched more than 9,000 objects into space — with nearly 800 in just the past year. While the benefits of this explosive rise in space-based ventures are many (better communications, scientific advancements and stronger national security, to name a few), there are drawbacks as well. The more congested space is, the more contested it becomes, creating challenges for both national and global security.
Here's a look at three of the biggest threats to satellites and what's being done to counter them.
1. Space weather
Space might seem like an empty, vacuous void, but in reality, the space environment is extraordinarily dynamic. Our solar system is bathed in a continuous shower of cosmic rays and salvos of energetic particles from solar storms — all of which can penetrate a satellite, microscopically fry its electronics, and, in extreme cases, render it useless.
One solution is to predict space weather to give satellite operators the chance to temporarily shut down part or all of a spacecraft to protect it. But this is surprisingly difficult. How do you forecast a space storm?
Recent scientific innovations hold promise. For example, at Los Alamos National Laboratory, a new machine-learning computer model accurately predicts damaging radiation caused by the intensification of Earth's Van Allen radiation belts two days prior to the storm, the most advanced notice to date.
The new model predicts future events by being trained and validated with existing satellite data sets from National Oceanic and Atmospheric Administration (NOAA), NASA, and Los Alamos sensors to learn important behavior patterns among the blobs of particles. With the expectation that similar, subtle patterns may repeat themselves in the future, the data-informed model — powered by deep-learning algorithms — makes forecasts by capturing critical indicators that are precursors to those future events. The Los Alamos team is now working to make the model better at predicting severe radiation events in near-Earth space, allowing earlier forecasts.
2. High-altitude nuclear explosions
If an adversary wanted to disable hundreds of satellites and severely hobble a country, launching a nuclear weapon into low-Earth orbit (LEO) and detonating it could do the trick. Although nuclear explosions in space have been banned since 1963 by international treaty, we need to be able to protect our space assets from a rogue nuclear event by knowing where we can move our satellites and for how long. We would also like to know if there are ways to reduce or eliminate any artificial radiation belt created by the blast.
To move a satellite, researchers here are developing a new solid-fuel rocket that could be stopped and restarted multiple times (something that has previously been a handicap of solid fuel thrusters) so satellites in LEO could quickly maneuver to a safer orbit. Solid rocket fuel is high thrust, safe, and low cost, plus it can be stored for extremely long periods of time. Los Alamos tests have successfully and safely demonstrated the ability to stop and restart the motor.
As for eliminating an artificial radiation belt, Los Alamos is partnering with NASA to send the first linear electron accelerator into space. The accelerator will produce an electron beam that can be used as a "virtual antenna" to generate the types of electromagnetic waves that are known to scatter electrons out of the radiation belts.
This new understanding, and a suite of new computer simulations being developed at Los Alamos, will let researchers determine if the experiment could be scaled up to actively scatter radiation belt electrons into the atmosphere where they would be harmlessly absorbed, no longer posing a threat to commercial and military satellites. This would go a long way to reducing the threat posed by a rogue nuclear blast in space.
3. Congestion in space
Currently, almost 3,000 operational satellites orbit Earth, and that number is rising due to the proliferation of launch opportunities for small satellites, primarily into LEO. Soon, we Earthlings will likely be launching more than 1,100 satellites per year, rapidly increasing the risk of collisions. Just one small crash could result in debris of thousands of BB-sized pellets hurtling through space in different directions at thousands of miles per hour. If just a few of those BBs hit another satellite, the shredded satellite would create more orbital debris, starting a runaway chain reaction.
Researchers at Los Alamos are working to mitigate that risk by developing an optical "license plate" for satellites called ELROI (yes, after the boy on "The Jetsons"). Solar-powered and the size of a Scrabble tile, it emits a unique series of faint blinks that are imperceptible to the naked eye, but can be observed with a small telescope to quickly identify and locate the satellite. Analogous to the beacon system on commercial aircraft to monitor and control air traffic around the globe, this license plate could be affixed to every spacecraft launched into orbit to track their movements. Then, if two satellites looked like they were on a collision course, the operators could be notified so they could maneuver the satellites out of the way (perhaps with the help of the aforementioned restartable solid-fuel rocket).
ELROI could also potentially help track adversarial spacecraft that might be used for nefarious purposes. A launch is hard to hide, but once you're in space, it's easy to get lost in the crowd, which makes space an appealing place for countries with illicit motives to operate in. While these countries are unlikely to identify their secret spacecraft with a license plate, if all other spacecraft were identifiable, it would be easier to pinpoint and track the needle in the haystack.
As space becomes more congested — and contested — the importance of protecting our assets becomes more critical. By investing in scientific research, we can make sure that, for every potential threat, we have technological answers.
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