satellite defense (or is it offense?)

Factual Questions
21

Being someone who worked near Goddard in Greenbelt Maryland, and, knew someone who worked there and got a nice tour of the place (I was on the ground floor, not on the catwalk). Needless to say there is VERY LITTLE space for a bucket of bolts or sand or whatever to be installed. Plus, you would need the control circuitry to exist (yet not interfere with anything else) that only you could detonate. Also, there is the cost of lifting these grains of sand up there. A launch is VERY VERY expensive. Also, very few people are allowed in, even fewer allowed on the ground floor, and, even fewer to the satellites.

Doing something like this would have to be done in the design stages of the satellite itself. To accomodate the sand, the detonation device, the circuitry. It’s not like you could duct tape this thing on there. And, as somone had stated before, space is a rather large area. Even immediately around the globe. Ok, imagine this: the entire surface of the earth with 1000 cars on it, all of them spread out. That’s what you would be looking at here. We get struck by thousands of meteroites every day, but, how often does a satellite get taken out? Or, even hit?

Also, GPS is not neccesarilly space based. You can also have ground based GPS transmitters, which they do. And, taking out this network would affect EVERYONE since EVERYONE uses it from hiking to landing a passenger plane to finding disabled boats at sea. You would piss off the entire world. Not just the U.S. military.

And, thinking some more, that would have to be an awfully BIG bucket of sand and bolts. It’s not like it will maintain its density and travel around like a satellite gobbling cloud. It will spread out in the direction it explodes (hey, which direction will it be pointed in?) and the cloud will get bigger and bigger and then it will become nothing worth mentioning.

It would probably be better to commandier an asteroid of comet, have it go in this dircetion, and then shatter it so there is a hueg spread of chunks heading right at us. Taking out sat’s as they hit them.

22

Point, GeorgeAECF. OTOH, a ground-based system can load pretty much whatever is wants, and has a potential payload measured in tons.

Jet Jaguar, perhaps it would hlep if we did a little definition of terms. IMHO, a ‘halfway decent’ IRBM has a down-range CEP of less than a 1000 yards. One can pretty-much be sure that at or near apogee, the error in the flight path will be rather less, but even if it isn’t less, that still gives you a fairly good chance to sling a hatful of sand into pretty much whatever you’d like.

A 3000’ CEP gives roughly 28,273,500 square feet of area to cover. Assuming a one-ton (2000lbm) payload, using pea-gravel, and assuming that pea gravel weighs 1/2 gram per stone, we have: 1,818,182 individual stones, or 0.064 stones per square foot of target area. Let us further assume that that a standard satellite only presents 10 square feet worth of target on it’s smallest cross-section (pretty conservatie, I think). That means that you a 64% chance of putting a stone into the satellite. Use three such missiles (or a three-ton payload), and you now are likely to hit the target with 6.6 stones. That should be more than sufficient to kill any satellite.

There are some fairly serious assumptions in this calculation:

  • That the CEP is quite large (probably not as big as I’ve used)
  • That the satellite presents at least 10 square feet of cross-section (in the case of many military satellites, probably 10 times this is more likely)
  • That the payload achives optimum distribution (debatable, and not all that likely)
  • That the launching nation has a good idea of the targets orbit (this is a big one!)
  • That the target doesn’t manuever (probably not)

This is just a ‘back of the envelope’ calculation to show general feasibility.

23

Actually, I just looked-up steel shot: #1 shot (~4mm) is 102 to the ounce, 1632 to the pound, 3,264,000 to the ton. This changes my above rough claculations to:

One ton payload: 1.15 hits per satellite
Three ton payload: 3.46 hits per satellite

That should do, nicely.

24

wouldn’t launching a hotshot payload, consisting of various-sized and -massed particles, into a very high orbit do the job of taking out the most satellites?

suppose particle size ranged between a cubic millimeter and a centimeter, and the substance ofwhich the particles are made weighs one gram per cubic meter. if this payload were to be launched into a very high orbit, these particles (thanks to their varying masses) would spread out over a wide range of orbit, would they not? the less massive (or is it more massive? it’s been years since a physics (let alone math) class) particles would assume smaller orbits, and on their way down in orbital circumference they would take aout a bunch of satellites.

in fact, due to atmospheric drag, the bigger particles would move their way down, taking out any satellites not taken out yet by the smaller.
the crystallizing liquid seems as if it would be the best bet for maximum damage. however, we need not be talking about damage caused by impact.

what if the particles were electromagnetically charged, or at least conductive, like a payload made of millions of strands of mylar. pop those babies into orbit. i envision massive crackles of electricity shooting through near-earth orbit.

jb

25

Depleted uranium? Nice and heavy…

But, even so… what speed will these scattered bits be traveling? I am sure any engineer will take into consideration a meteorite strike… and they are traveling at a pretty good clip and vary in size from a spec of dust on up… hmm… Also, considering the weight requirements of satelittes I doubt anything containing iron will be going up there so magentics will do nothing.

The mylar sounds interesting, but, the sun itself puts out a serious amount of radiation and all the satellites are insulated from both heat and electricity. Also, I don’t see a charge building up unless the conductive strips would act as a capacitor or other such device, or, have access to such a charge to do any damage. Plus, they would have to touch a sensitive part of the craft suspectible to such a charge. Which, would limit it to: solar cells, antenna/dish array (assuming neither have any precautions taken against a static shock, most integrated circuits now do these days).

One last thing, your shotgun approach, if you get the best odds, will STILL have to hit a critical part of the sat. They are designed to be redundant as much as can be, and, can also work around a damaged part at limited capacity. they have been doing this type of thing since the 70’s. Back then a sat. could loose upto 30% some off percent and still function. So, if you get your 3 shot into a sat. they will have to make it through any shielding, hit a circuit, hit something very critical. Or, something that is one of a kind or some structural member that will cause it to fail or loose orbit in some way. All which is very tough.

Mercury? Launch the vehicle and spray teh mercury on the hot side of the planet where the space will be warm enough to keep the mercury liquid. If you get a good aerosolization you’ll get a nice spread, maybe have it pulse to vary the size of the droplets. In their liquid form they may work their way into the sat. and short any circuitry. In solid form they will become BB’s and may cause mechanical damage. Maybe penetrate any shielding or skin, then, when they get hot (assuming the perforation through the shield was enough) they will melt and short any circuits. Exposed circuitry that is. They do put a coating on boards to prevent mechanical abrasion and static charge.

26

The solar wind is highly charged. Satellites are built to handle it. Mylar is an insulator so it won’t do any damage. Besides, no sane engineer would use un-insulated wires, let alone leave it exposed to the outside. Electrical circuits are all enclosed in boxes - not airtight, but not easy to get to. So even if you threw aluminum shavings at a satellite, you won’t cause any short circuits. Of course there are many things that would malfunction if covered by a foreign object (e.g. radiator, cameras, attitude control jets) but you’d need a big sheet of aluminized mylar to do that with a reasonable chance of success.

27

One of the problems with analyses like this is that they’re ignoring orbital mechanics! If you’re dumping a barrel of sand in LEO, the pebbles will be cranking along at around 17,500 mph. Oh no! Lethal projectiles! Well, no. Everything else in that orbit will be cranking along at that same speed, so if they get hit by a pebble, it will make a small, inaudible “clank!” and go about its business. If you, instead, try to launch the pebbles “straight up” so they have little or no tangential velocity, they’ll fall right the hell back down.

The main things that some people are missing are 1) Space is big, and it’s really really hard to get one thing close to another thing, and 2) once you’re in an orbit, it’s yours to keep. It takes a bunch of energy to get to another orbit, and just dumping (or even exploding) a bunch of sand won’t get you there.

So what’s stopping some nutjob from sneaking a few pounds of sand onto a rocket or into a shuttle? Well, most places in the West have pretty decent security, but I bet that somebody could get something by somewhere in the world. It wouldn’t matter if they did, though - all they’d accomplish is putting a small cloud of debris into an orbit around the earth. If that orbit was the same orbit shared by another satellite, you wouldn’t have enough of a velocity differential to make a difference. If it was a different but intersecting orbit, you’re back to the “space is big” thing.

28

There’s no need to worry about objects moving in the same direction and the orbit, but objects in a different orbits that happens to intersect yours can be a distinct hazard. If a military satelite happens to be orbiting N to S at 17,500 mph, as many do, it will not enjoy the encounter with a grain of sand moving in the far more economical W to E orbit at about the same altitude. Making the orbits intersect poses a bit of an aiming problem, but you can make up for poor aim by adding more projectiles, or increasing the time frame that you’re willing to wait for a hit. If you don’t intercept on the first orbit, the projectile will just swing around the earth for a 2nd, 3rd, or thousandth go at it.

29

Actually, the only way the shot / sand / whatever would be matching speed & orbit is if the shot and the target on the exact same orbit. Any other orbit and you’ve got a delta-V. Reciprocal trajectory, and your speeds are additive. Converging paths will give your closing speed as a vector sum, likely still very high.

Yes, space is big, but most satellites follow fairly predictable orbits, greatly simplifying the intercept solution.

I suppose some satellites could take multiple hits and survive with some capability remaining, but not many, I’m guessing. If it’s a KH-11 or similarly-sized, it’s likely to be more like 34 - 35 hits, which even a well-protected satellite will find hard to shrug off.

30

Tranquilis, the shotgun approach has been tried before and is quite feasible (it’s the second easiest type of antisatellite warhead to perfect), but experience has demonstrated that it is much harder than it sounds. The problem is not with the warhead, but with getting it on target.

What you are missing is the fact that space is not just big, it’s really, really, REALLY freakin’ huge. In orbit, passing within a few dozen miles of something is considered a very close call. Getting within 3000’ of your target (even one with a predictable orbit) without any sort of precision terminal guidance is quite an achievement. And not only are you trying to hit a specific point in 3D space, you also have to do it at the exact moment your target will be there. Remember, those satellites are covering 4 to 5 miles per second and would pass through the target zone in about a quarter of a second. Then there is the problem of aiming a rocket that was designed to hit a target on the ground, rather than one in mid-flight. This could be fixed, but would require a considerable amount of prototype engineering (especially without tech support from the vendor :)) that your average warlord, president-for-life, or eccentric multibillionaire media mogul just doesn’t have.

The level of precision and engineering talent required is beyond the reach of a rogue nation with a few extra Scuds lying around. Even China, Japan, or the ESA might have a bit of trouble, simply because they don’t have the experience with rendezvousing spacecraft in orbit.

There is one type of warhead that would be effective, and doesn’t need too much precision to get on target. That would be a nuclear weapon. The danger lies not in the explosion (though that would do the job if it were close enough), but the EMP. The U.S. developed such a weapon in the 1960’s, and determined it would burn out the electronics in every satellite within 600 miles. It was eventually abandoned because the weapon is not selective and would take out friendly satellites that got too close as well, but that’s not a concern if your goal is just to cause general havoc. (However, if some rogue nation/individual got a hold of a nuclear IRBM, they would more likely turn it on a major city than detonate it in orbit.)

31

No, the particles wouldn’t spread out because of their mass. The gravitational acceleration of all of the particles are equal, regardless of mass, and they would pretty much stay in the same orbit. (There would be some spreading due to slight differences in their initial velocity and heading, but that has nothing to do with their mass.)

There’s a fundamental problem with your liquid warhead idea. In space, liquids don’t stay liquid for long, but they generally don’t freeze. Instead, they sublimate directly into a gas. Remember, phase is determined by pressure as well as temperature. The Space Shuttle routinely dumps hundreds of gallons of excess water overboard (it’s a byproduct of the fuel cells it uses to generate electricity) with no ill effects.
All in all, I don’t think it’s possible to make space effectively dead, short of the U.S. or Russia specifically targeting and shooting down every single individual satellite.

32

You seem to be assuming that the only thing anyone would want to do would be to knock down a single missile or satellite at a precise time and position in space. If the goal is the more general one of making a nation’s space assets unreliable there’s no need to be so picky. It might be sufficient just to launch a load of sand into orbits that roughly intersect the orbits of a variety of different satellites. Over a few months time, a few million rocks distributed through low earth orbits can sweep a remarkable volume of space. That makes space more hazardous for anything up there.
Granted, it would take some effort to pull off, but all this talk of sophisticated guidance and difficult tracking problems sounds like baggage dragged over from star wars style missile interception systems. This is not necessarily the same problem.

33

Squink, I think you are beating a dead horse here with sand or anything (what are you planning?). Any ways, i did some quick calculations for everyone… I calculated the volume of space between 650km (406 mi) (LEO) and 36000km (22,500 mi) (geo-stationary, etc.) sat. orbits above the earth.

This is the volume of space where you will find your satellites to hit: 317,532,356,543,293 cubic km or 198,457,722,839,558 cubic miles.

I think we are talking about MORE than a bucket or two of sand here. Hell… we are talking about more than one or two ENTIRE payloads from the space shuttle filled with sand. Maybe two giant concrete blocks from within the space shuttle… set on an orbit in tangent to most… maybe it will get one one day. Maybe, two tied together like a boa or something and set on a spin to encompass a range of altitudes you’d hve more chance… assuming it did not go elsewhere.

34

Your calculation of the volume of space out to geostationary orbit ignores the fact that most satellites hang out in either low earth orbit, or geostationary orbit. (Satellite distribution) – (more calculations. ) By targeting just those regions you can knock several zeros off of the volume. Space debris is a serious problem even without deliberate attempts to make it worse. (Orbital debris FAQs)
If debris is as inconsequential as you imply, can you offer an explanation as to why so much effort is being spent on modeling and tracking the stuff; or why insurance companies are concerned about the “cascade effect” ?
Debris routinely hits and damages the shuttle. Fortunately it can be deorbited and serviced between missions. Satellites are not so flexible.
Since we have already managed to, unintentionally, make space more hazardous than it was a few decades ago, it stands to reason that if we put some effort into making matters worse, we will succeed.

35

Ah! Now this is indeed a point I’d been missing. Point made: It’s feasable, but would require major effort, an effort that would almost certainly be detected, and would take years to perfect.

Gotcha.

36

Most of the comm sateliites and all GPS are geo-stationary… main reason being stationary over a particular are over the planet and more coverage. Knocking out the lower ones would have some affect, but, the ones that would cause the most havoc are still way way up there. What be the reason to knock out a satellite unless it had some serious affect? GPS would be nice and big, affect miltray, planes, search and rescue, etc.

Any ways, I re-did the calc’s to orbital altitudes between 650km/406mi and 1600km/1000mi… which leaves us which a much smaller volume:

656128242577 km^3 or
410080151610 mi^3

Yup, certainly smaller… but, still a rather large space to think about. I think the major problem here is actually visualizing a space so big.

And, the main reason that the space shuttles have repairs done on them is the fact that they carry people. Therefore they must positively be 100% all the time. A tiny nic on any of the glass on the shuttle and its replaced, even microscopic scratches. Satellites do not carry people, are smaller, and therefore are built and designed a such. Let’s say one bank of electronic circuits has been comprimised somehow… no biggie, just disable it and work at reduce capability until a repair comes in. You can;t do that with a person. Also, most are over-redundant, and, not all use what they have at any given time. Because of the massive expense involved with a satellite deployment, the satellites are designed with more than what they had intended to compensate for future expansion. It’s not like a desktop computer where you can open the case up and pop in more RAM. You gotta send someone up, locate, and then repair/upgrade the satellite and NASA does not guarantee this. So, you consider the obvious. Over redundant and more than what you need.

37

Ok, this is right up my alley, so this is going to take a while.

  1. Launching a fake satellite: In the US companies, not the gov’t, build rockets. To go to Russia or ESA you have to fill out an amazing amount of paperwork. Don’t even think about China. Of course, if you’re doing this, you’re probably not worried about export laws.

  2. cont’d: Launch vehicles (as we like to call the rockets) are really expensive. $20 million for a very little one, up to $150 million for GEO. And that’s without the fake satellite, fake company, etc. There’s only really a few companies who make satellites, so they’d be checking you out, not just for money, but your engineering too, so you don’t make their rocket blow up (makes em look bad).

  3. Nefarious device on legit satellite: A ridiculous number of people review the design for each part before it is made. Then they send it to the customer, who repeats the process. Then the techs put it together, and they’ll let you know if it doesn’t seem right. Other engineers check the tech’s work. Then it’s tested to make sure it works. Repeat several times. Before the launch, all of the above check everything over real close. Add in the launch vehicle people, for the reasons in #1. This explains why I get annoyed whenever a movie says “The gov’t gave him a bazillion dollars to build a device, but he did it all alone and nobody else has any idea what it is or how it works.”

  4. Hiding sand on legit satellite: See above. Plus, it’d be hard to sneak it in, because of security and there’s no where to put it. Those things are packed tighter than your Mom’s suitcase before a 3 week trip to Europe. And it’d be noticed on the weight check unless it was too tiny to do anything.

3: Sand spreading out to get other satellites: As mentioned above space is really, really big. Also, it won’t spread out like throwing a handful of sand in the air. Stuff will go in the direction in which it is originaly pushed/launched/whatever. If the sand is in a relatively low orbit, the air drag will cause it to degrade and eventually burn up in the atmosphere, probably loooong before it got to another satellite, much less a bunch of satellites in different orbits, unless you targeted one satellite, and were dead on. Launch vehicles are not precise on that scale.

Yes, space junk is considered a problem, and it is tracked. But, I can’t think of one satellite that failed due to orbital debris. Maybe degraded at the end of its design life, but not destroyed. Per the orbital debris FAQ referenced above, “Only one such incident [collision of 2 large objects] between objects from different missions has been recorded in 45 years.” I can’t believe that the amount that could be launched at once could have more of an effect than all the debris that’s up there already.

There are more satellites that have malfunctions of the satellite or the launch vehicle. There used to be a great video on space.com of a Delta II blowing up really early in the launch.

The other, probably better ways to take out a satellite have already been mentioned.

38

There is a lot of damage to be done in low earth orbit.
KH-11 optical satellites orbit at ~300-1000 km. Radar units are also necessarily low, while some signals intelligence platforms like Magnum have elliptical orbits with apogees out near geosynchronous, and perigees of ~340 kilometers. These are some of the most expensive bits of hardware ever orbited, and some people would be very upset if they stopped working.

When you put that number in standard form, it’s:
6.56 X 10[sup]11[/sup] km[sup]3[/sup].
To get a sense of the magnitude of the problem, that needs to be compared with something like The number of 3 mm cubes of copper that will fit in a 1 cubic meter volume:
3.7X 10[sup]7[/sup]
That turns out to be enough particles to cover a 37 square kilometer area at a density of 1 particle per meter. If those particles are distributed in space in a ~300 km orbit, they will sweep out 1.5X 10[sup]6[/sup] km[sup]3[/sup] with each orbit. That’s a volume of ~6.6 X 10[sup]9[/sup] km[sup]3[/sup] per year, which goes a long ways towards explaining why paint chips from old boosters actually do collide with things on a regular basis. Space is big yes, but speeds are high and everything is going through the same neighborhood over and over.

Of course since every satellite up the needs to cross the equator twice on each orbit there’s no need to fill the whole 6.56 X 10[sup]11[/sup] km[sup]3[/sup] volume anyway. A ring of material would do the job as well, and would require far fewer particles. This argument also applies to the geostationary satellites which are all lined up in a single orbit directly over the equator. There’s already major concern that the destruction of one of these would trigger a chain reaction that destroys everything in geosynchronous space. Fortunately very few nations can reach that orbit, and the ones that can are unlikely to be throwing sand around when they do.
The GPS system, which operates from several different ~20,000 km non-geosynch orbits is probably protected from low tech attacks by the sheer volume of space, but that’s not the only valuable thing up there.

Everyone has been actively trying to keep space debris down. If your “space is big” argument held water:
•No one would worry about space debris. -They do.
•There would be no collisions of any size. -There are.
What do you think the hazard would be if all those floating specks were replaced with BB’s ?

The term better depends on what, exactly, you want to do. If you want to surgically remove a single offending satellite, a high tech interceptor is probably the way to go. If you just want to release generalized havoc and mayhem, there seem to be other, lower tech, options.

39

wowo!

thanks all. this thread has been better than i imagined!

how effective would a potato-gun launched apparatus be? you could fit more mass (no pesky engineers to demand you keep weight down), which is a good trade-off for a sucky orbit. see Wikkit’s post in this post.
jb