Research Underway to Enable Satellites to Permanently Orbit in Very Low Earth Orbit
February 9th, 2025Is this actually going to happen?
I don’t know why, but Cryptogon is read by many people who are qualified to provide a sanity check on this. I hope they comment.
Needless to say, it would be very bad if remote operated/autonomous weapon systems were able to use realtime, high definition imagery, available planet-wide, for ISTAR.
This would be very, very bad. Double plus bad.
Current systems require tasking (with sometimes lengthy delays) or deployment of assets that have limited loitering durations.
As you continue to be fleeced to within an inch of your life for energy, the space based control grid… Fuels itself?!?
Via: BBC:
“When you start describing it to people, it starts to sound like a perpetual motion machine,” says Spence Wise, senior vice-president at Redwire, an aerospace firm in Florida. A perpetual motion machine is not meant to be possible. But it almost is, in this instance.
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This new generation of orbiters could enable ultra-high-definition surveillance of activities on the ground, or superfast satellite-based communications.
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They are developing technology to harvest molecules from the thin layer of air that is present in VLEO in order to actually propel satellites here. Such a system, called Air-Breathing Electric Propulsion (ABEP), has been made possible by advancements in electric and ion propulsion in recent years. In essence, it involves fixing a large bucket or opening to the front of the satellite, into which gas molecules from the atmosphere flow before they are ionised to create plasma that generates thrust.
“The idea is to use the same air slowing down your satellite as a propellant,” says Francesco Romano, a scientist at the Swiss Plasma Center in Lausanne, Switzerland, who has previously studied this technology. Using electric and magnetic fields, the engine would ionise gas from the atmosphere, taking away one electron from each molecule, to produce a free electron and an ion. Then, using magnets, the electrons and ions are pushed out the back of the spacecraft, producing thrust. “Theoretically, if you can generate a thrust that is the same as your drag, you stay at this altitude for an infinite amount of time,” says Romano.
To date, an assortment of experimental ABEP systems have been able to produce relatively small amounts of thrust at ground level, but their feasibility in orbit has yet to be properly tested.
It’s probably already in place
https://news.mit.edu/2018/first-ionic-wind-plane-no-moving-parts-1121
Its possible until the onboard power system runs out or breaks. This doesn’t violate the second law of thermodynamics because the unit has a power source (I imagine solar cells, but it didn’t say). It doesn’t violate conservation of momentum, either, because they are picking up stuff in the front and throwing it it (hard) of the back, so this can “fight” the inevitable frictional drag force with the sparse atmosphere. How long do solar cells last? 20 years? Why? because entropy always increases. The second law always gets you in the end!
Reader JB sent this:
This is basically attempting to put the Bussard ramjet concept to work for low Earth orbit instead of interstellar destinations. (Some researchers since the 1950s have supposedly calculated that such a design would always create more drag than thrust for interstellar conditions, sadly.)
Here’s the deal, the density of the atmosphere decreases roughly *exponentially* with height. Look up “US Standard Atmosphere”. The halving height is about 18,000 feet. Sea level 15 psi, then 7.5 psi around 18,000 feet, then 3.75 psi around 35,000 feet where commercial airplanes fly, then 1.9 psi around 55,000 feet where the Concorde flew, etc.
https://www.engineeringtoolbox.com/standard-atmosphere-d_604.html
The “US standard atmosphere” only gives numbers up to 250,000 feet, and the “edge of space” is ~328,000 feet (100 km), but the exponential rule still roughly holds even up through the altitude of the International Space Station (420 km) and Starlink / Iridium / Globalstar / visual spy satellite / etc constellations which are largely between 500 – 800 km.
All of these objects experience drag from our atmosphere, even though they’re “in a vacuum” or “in outer space” or “outside our atmosphere”.
https://heavens-above.com/IssHeight.aspx?lat=0&lng=0&loc=Unspecified&alt=0&tz=UCT
In fact, where did this magical 100km “edge of space” number come from? He calculated that the velocity required for a WINGED airplane to generate enough lift to stay aloft would, at that altitude, equal the velocity required to just go ahead and be “in orbit” (which just means moving forward fast enough that the earth falls away from you at the same rate you fall down toward it, so you go in a circle), at which altitude there would be no need and thus no purpose to having wings any more. But if you think about it, if you go orbital speed at that altitude, if there’s enough air to theoretically give you your own weight’s worth of lift, then there’s definitely enough air to give you a very appreciable amount of drag, too.
And that is what we see. The first manned orbits in the 1960s reached often only 150 – 200km, and if you listen to the mission control audio they’ll say things like “OK we’ve calculated you are good for at least 3 orbits.” Because at such a low altitude, there is so much drag you will actually reenter within just a couple hours.
At “very low” altitude, let’s say 200km, reentry probably happens within days.
At ISS altitude (420km), reentry happens within high months to low years.
At 500-600 km altitude, maybe reentry happens in 5-10 years.
At 800km altitude, reentry won’t happen for decades to possibly centuries.
So, spy satellites typically like to fly “as low as they can for better resolution” but because they cost $1B apiece they don’t want them to burn up quickly, so they tend to hang out higher than ISS, let’s say 500km.
The best possible improvement I can imagine getting from the proposed ionic scoop propulsion technique would be to maintain a stable orbit somewhere in the 150-250km range.
GOCE pioneered the technique albeit with a propellant tank not a scoop, but the solar power requirements are really gonna be the limiting factor, and that would only get worse with a ram on the front. Unless you stick a fission reactor on it, that might help some. Problem is, that fission reactor is guaranteed to vaporise its uranium and byproducts into the atmosphere as soon as something fails in the propulsion system
https://en.m.wikipedia.org/wiki/GOCE
https://en.m.wikipedia.org/wiki/Kosmos_954
So, we’re only talking a resolution improvement of 2-3x over current spy sats. Bottom line: YAWN.
The far bigger threat in my opinion is that Elon has dramatically lowered the cost of launch by at least an order of magnitude, which means now there can be thousands of spy sats active at once, instead of the former dozens. Makes it impossible for any given fixed sensitive-site-on-the-ground to have any windows where there’s not a spy satellite in view.
They are still limited by only being able to optically look in one direction at a time, so it really still is not “video of the entire planet’s surface at 1m resolution or better 24/7 all points all times”. Also the bandwidth/storage requirements for that would be staggering. But if you are a “thing of interest” it is certainly very difficult to hide these days.
All the best