Low Observability in space

[My2Cents]

stupid question why do need cool the mirrors?
Don't mirrors have limits to where they can be used (particular Azimuth limitations) hences the preference for the space based in some circles.

No mirror is perfect. Even if you reflect 99.9% of the energy of a 100 MW beam, the mirror has still absorbed 0.1 MW as heat. First it warps, then melts. :rel

I thought Nuke bunker busters got canceled if I remember it was something Rumsfelt disagreed with congress over

They were cancelled. The cause was when people realized that there were 2 political problems.

The lesser problem was that the weapons were a subsurface detonation that would generate a lot of fallout.

The greater problem was that the justification for building them -- to destroy nuclear and bioweapon faculties buried to deeply for conventional weapons to effect before they could produce weapons to be deployed – almost always required first use of nuclear weapons by the USA, and Rumsfelt could produce an acceptable criteria for when 1st use would be acceptable. Given that, Congress felt they could not justify the funding the development for a weapon that could not be used. :rolling

But they could be built.

 

[Belesari]

QUOTE=harryriedl;216087]stupid question why do need cool the mirrors?
Don't mirrors have limits to where they can be used (particular Azimuth limitations) hences the preference for the space based in some circles.

No mirror is perfect. Even if you reflect 99.9% of the energy of a 100 MW beam, the mirror has still absorbed 0.1 MW as heat. First it warps, then melts. :rel

They were cancelled. The cause was when people realized that there were 2 political problems.

The lesser problem was that the weapons were a subsurface detonation that would generate a lot of fallout.

The greater problem was that the justification for building them -- to destroy nuclear and bioweapon faculties buried to deeply for conventional weapons to effect before they could produce weapons to be deployed – almost always required first use of nuclear weapons by the USA, and Rumsfelt could produce an acceptable criteria for when 1st use would be acceptable. Given that, Congress felt they could not justify the funding the development for a weapon that could not be used. :rolling

But they could be built.[/QUOTE]

The problem with ground based lasers is that the atmosphere absorbs the laser if its not adjusted right frequency. Plus those mirrors are going to be Large and take damage over time from being in Orbit.

The most effective weapon available to used from space is and probably always will be a large mass excellerated at high speeds.

The biggest problem with ground based lasers is simple. They dont move.

He who controls the orbitals wins.

 

[My2Cents]

The problem with ground based lasers is that the atmosphere absorbs the laser if its not adjusted right frequency.

That is simply an engineering detail. The chemical oxygen iodine laser in YAL-1 does it by producing a laser beam tuned for iodine, which is barely measurable in the atmosphere. Free election lasers can be tuned to dozens of even better frequency windows.

Plus those mirrors are going to be Large and take damage over time from being in Orbit.

They are not that large, especially when folded, and would be light for their size. A single shuttle trip could transport 1 relay mirror or 2+ fighting mirrors, possibly more, per trip.

Everything takes damage over time, no matter where it is. One advantage of being in space is that you do not have to worry the damage from the 2 most destructive chemicals known to man – oxygen and water.

The most effective weapon available to used from space is and probably always will be a large mass excellerated at high speeds.

Depends on the target. It is like arguing about whether your company should have mortars or machine guns. -- The correct answer is you need some of both. :daz

Impactors are good for large hardened immobile targets, there is no way for a 8kps missile to see through the plasma surrounding it within the atmosphere, so moving targets are out. And the blast area is large, so you cannot use them when collateral damage is an issue.

The laser is the opposite, a precision weapon that work best on small targets that are no more than lightly armored, and the short flight time makes hitting a moving target possible. You can target a single person in a crowd and probably only injure 2 or 3 others in the process. A laser can destroy a car, but destroying a tank will be very difficult, and destroying a deep bunker is simply not practical. Do not expect to vaporize a city with a laser, but setting a lot of fires should be easy.

The biggest problem with ground based lasers is simple. They dont move.

No, they don’t. But they can be a very hard target, only the relay mirror has to be exposed on the surface, the lasers can be deep buried. And the orbital mirrors allow the laser to hit almost any point on the face of the earth that the orbital mirrors can see with little or no warning, and, if you are using free electron lasers, can keep firing as long as the electric grid is intact. :hul

He who controls the orbitals wins.

Another old quote, but still very true.

 

[Armoredpriapism]

Why not have the important satelites simply transmit via laser datalink to unimportant satelites? If the important ones were stealth they could lie dormant until the anti-satelite strike is over then start transmitting when needed. Or you could just have a huge network of cheap "hub" satelites that did nothing but receive data from other satelites and act as relays to the ground.

 

[My2Cents]

Why not have the important satelites simply transmit via laser datalink to unimportant satelites? If the important ones were stealth they could lie dormant until the anti-satelite strike is over then start transmitting when needed. Or you could just have a huge network of cheap "hub" satelites that did nothing but receive data from other satelites and act as relays to the ground.

1. There are enough aiming errors that, at any appreciable range, you will have to spread the beam enough to produce reflections off the receiving satellite that can be observed. Enough data over time and they can deduce the general direction and orbital period of the transmitting satellite. That should be enough to narrow down the search to a reasonable area using star occultation.
2. Some of the most important satellites are the communication satellites and things like GPS that have to transmit openly.
3. Satellites are cheap. Putting them in space is expensive, and once launched they have a limited life span based on the supply of onboard maneuver fuel and ultimately due to degradation from radiation and solar wind. It is probably more cost effective to put stealthed inactive replacements in higher orbits to be activated as needed when preparing for war. Another alternative is to have replacements ready for launch when needed.

 

[wormhole]

The Chinese and US ASAT tests were completely different. The Chinese eased a satellite with a bomb on board up next to the target and set it off, the equivalent of a truck bomb in space. The US used a missile launched from a Navy destroyer and scored a direct hit on the target head with a closing speed of 36,667 km/hr.

The Chinese system is good for taking out select satellites at the opening of hostilities and can be used in any orbit, if they do not spot it moving in and take evasive action in time. The US system allows almost no time to respond, but is restricted to low orbit.
.

The Chinese have actually demonstrated a hit-to-kill capability a couple of years back on a target in low earth orbit similar to what the US and, I believe the Israelis, have demonstrated. This is different from the stunt they pulled destroying that satellite that scattered debris all over the place.

 

[StingrayOZ]

I don't think the US is in a position to lecture the chinese about space polution. The US put several million needles into orbit creating a orbit of debris that they could bounce signals off. They thought they would be out of orbit after a few years, they are still up in orbit.

The chinese are where the US were in the 1970-1980's. They have made huge gains, and seemingly indiginously.

The USN launch was more impressive because its done from the surface with a weapon not even designed to do it. While it only took out a very low orbit sat, these are the ones that may be launched during war time to cover an event. The US demonstrated its ships could pull these out of the air at any time using at sea technologies today. It could handle any technology even ones with closing speeds above hypersonic (ultra sonic, mach 30?).

I could imagine some bigger VLS tubes being fitted to larger ships, allowing the same capability but to sats in regular LEO. These could be deployed over the equator.

 

[My2Cents]

I could imagine some bigger VLS tubes being fitted to larger ships, allowing the same capability but to sats in regular LEO. These could be deployed over the equator.

The ones in a Trident sub should be big enough to handle an SM-3 with strapped on boosters to get it to higher orbit. You would probably have to surface to launch. Targeting data comes from a source outside the sub, but for an orbital target that would be necessary anyway because so much lead is required.

It is not a perfect design, but it should work and be relatively cheap to implement with mostly existing hardware. :sniper

 

[Armoredpriapism]

I think the US should focus on protecting its satelites more than destorying chinese satelites. Let's say a bunch of silly stuff happens and all of the sudden there's a high-stakes stand off between Taiwan and the government of China. All of the sudden we notice the Chinese blinding or frying our satelites with ground based lasers. What can we do with naval missiles? If we attack their lasers or satelites it means all out war, right? So shouldn't we be focusing on making our satelites hard (and expensive) to defeat and impossible to ignore?

 

[My2Cents]

I think the US should focus on protecting its satelites more than destorying chinese satelites. Let's say a bunch of silly stuff happens and all of the sudden there's a high-stakes stand off between Taiwan and the government of China. All of the sudden we notice the Chinese blinding or frying our satelites with ground based lasers. What can we do with naval missiles? If we attack their lasers or satelites it means all out war, right? So shouldn't we be focusing on making our satelites hard (and expensive) to defeat and impossible to ignore?

You are only a couple decades late with this idea. They have been hardening satellites against various attacks probably since the late 1960’s. :hul

Targets and defenses for laser attacks.

• Solar panels and heat radiators are the most vulnerable parts of a satellite because of their large size, and by their nature are very difficult to armor must absorb light. If possible during an attack they can be turned edge on to the source to minimize damage, but in any case cumulative damage will eventually reduce satellite capabilities.
• Optical sensors are obvious targets and are protected using fast acting electric shutters similar to those used on nuclear bombers to protect the flight crew from blinding, and other optics from lasers. These also help protect the sensor from being accidentally pointed toward the sun.
• Communications antennas typically not very vulnerable due to a combination of size, materials, reflectivity, etc.
• The body of the satellite is vulnerable only if the attacking laser has sufficient power to heat it to the point that the internal electronics shutdown, or the satellite start to melt. This requires a weapon grade laser suitable for ABM work. Spinning the satellite helps a little by spreading the heat over a larger surface from which it can radiate when facing away from the laser, and insulation will slow the attack, but at these power levels the eventual failure is probably inevitable.

In the area of response, if we attack their ground based laser inside their own territory that would be an act of war, but then so is attacking our satellites. An appropriate response, after presenting the case to the UN, would be to destroy an equal number of their similar satellites if a satisfactory outcome at the UN is not forthcoming. :argue

 

[PCShogun]

Generally, there are lots of ideas that can be used to take out a satellite, and while no one said it specifically, the international Space station.

Lasers are now strong enough they can destroy the receptors on most satellites from Earth's surface. Since they are not armored, lasers would eventually be able to defeat the satellite directly, assuming we couldn't do it now.

Rail gun technology is also advancing quickly, Shoot a 2 kilo rock in space at 3 kilometers/sec (about Mach 10) and that rock isn't going to stop, period. Make it out of something that can withstand atmospheric re-entry and you have a pretty neat man-made meteorite with tremendous kinetic energy. Tests showed a two kilo tungsten projectile would pass completely through a tank at these velocities from a 9 megajoule railgun. The Navy just test fired a 33 MJ railgun in 2010. I doubt an aluminum skinned satellite or space stations would stand a chance.
However, launched from space to surface, I expect accuracy would be an issue, as atmospheric buffeting would cause deflection in an unguided weapon.

The last ASAT missiles were tested in 1985 and the program cancelled in 1988 when the initial cost of $500 million had climbed to $5.3 billion. Talk about under bidding.

 

[My2Cents]

Rail gun technology is also advancing quickly, Shoot a 2 kilo rock in space at 3 kilometers/sec (about Mach 10) and that rock isn't going to stop, period.

You will need at least twice that velocity to hit a satellite in low earth orbit, and that does not include velocity loss from atmospheric friction.

Tests showed a two kilo tungsten projectile would pass completely through a tank at these velocities from a 9 megajoule railgun. The Navy just test fired a 33 MJ railgun in 2010. I doubt an aluminum skinned satellite or space stations would stand a chance.

Depends on where it hits and the level of redundancy in the target. The simple fact is that a solid round is not very effective against unarmored targets. It is like firing an APDSFS round at a canvas tent, the round penetrates to easy and does not transfer enough energy to the target to cause large scale destruction. Basically this is just another meteoroid impact, but larger and slower than usual. Satellites are usually too small to be highly redundant, so there is probably a 50-50 chance a single hit would kill one. A space station on the other hand would probably require each compartment to be holed, and in a short enough space of time to overcome repair attempts.

Don’t use a solid penetrator, what you need is something like an AHEAD round, if that is possible for a railgun.

 

[PCShogun]

You will need at least twice that velocity to hit a satellite in low earth orbit, and that does not include velocity loss from atmospheric friction.

True, I was referring to a hypothetical space mounted rail gun. Currently they can mount these on a destroyer sized vessel. If already in orbit, it would not need to be as big or as powerful.

Don’t use a solid penetrator, what you need is something like an AHEAD round, if that is possible for a railgun.

Yes, that would work, and the velocity would not be any greater than being fired from a cannon, perhaps less as acceleration is not as violent.

 

[My2Cents]

True, I was referring to a hypothetical space mounted rail gun. Currently they can mount these on a destroyer sized vessel. If already in orbit, it would not need to be as big or as powerful.

Yes, that would work, and the velocity would not be any greater than being fired from a cannon, perhaps less as acceleration is not as violent.

Don't forget the effects of recoil on a space craft. The railgun would probably have to be fixed mounted on the thrust axis of your spaceship. To prevent tumbling

Just move into an close orbit in the opposite direction and deploy the 4th stage + kinetic warhead of SM-3 missiles. Self-guided, better designed impactor, and much lighter. Or if you can align you orbits to cross and then divert in time, a bag of buckshot should do the job. :argue

 

[harryriedl]

Just a thought to add would a moon orbit greater protection against any form on ASAT vs the much more limited target window be worth the effort(if you could get a decent payload that far). Would a Moon GEO with a rail gun or KE type weapon A be workable be worthwhile

 

[My2Cents]

Just a thought to add would a moon orbit greater protection against any form on ASAT vs the much more limited target window be worth the effort(if you could get a decent payload that far). Would a Moon GEO with a rail gun or KE type weapon A be workable be worthwhile

What is a "KE type weapon A"? (a typo?)

Because of the distance (380,000km for lunar orbit, vs. 26,000 km for GEO, and 2,000 km (max) for LEO) hitting with an unguided projectile from one at the other would purely a matter of luck, terminal guidance is required.

Defensively, putting a target farther away always has value, but typically reduces or eliminates any military value as well. About the only system that would make sense at that distance is a retaliatory strike capability.

 

[harryriedl]

What is a "KE type weapon A"? (a typo?)

Because of the distance (380,000km for lunar orbit, vs. 26,000 km for GEO, and 2,000 km (max) for LEO) hitting with an unguided projectile from one at the other would purely a matter of luck, terminal guidance is required.

Defensively, putting a target farther away always has value, but typically reduces or eliminates any military value as well. About the only system that would make sense at that distance is a retaliatory strike capability.

guided KE weapon. So their would be utility as retaliatory but no more

 

[Belesari]

The only real space based weapons i've seen talked about seriously for near future aps are KK weapons. Rods from God.

Simplicity really. Rods at max the size of telephone poles. Mostly just tungstone or steel or iron with a heat resistant coating. Dumb guidance. a hit from one of those at GEO or even LEO is game over for anything.

guided KE weapon. So their would be utility as retaliatory but no more

 

[My2Cents]

The only real space based weapons i've seen talked about seriously for near future aps are KK weapons. Rods from God.

Simplicity really. Rods at max the size of telephone poles. Mostly just tungstone or steel or iron with a heat resistant coating. Dumb guidance. a hit from one of those at GEO or even LEO is game over for anything.

"Rods from God" are an orbit to ground bombardment weapon. While originally there was a lot of hope for them, particularly for destroying deep bunkers, additional research showed that penetration would be much less than had been assumed (Basically they would be going too fast when they hit, which changed the behavior of the materials involved.)

Plenty of other weapons are practical for near future ABM and orbit-to-orbit applications. The problem with them, and ‘Rods from God’, are that you need to abrogate the various treaties against the militarization (or more properly the weaponization) of space. :ban

 

[Palnatoke]

Don't forget the effects of recoil on a space craft. The railgun would probably have to be fixed mounted on the thrust axis of your spaceship. To prevent tumbling

Just move into an close orbit in the opposite direction and deploy the 4th stage + kinetic warhead of SM-3 missiles. Self-guided, better designed impactor, and much lighter. Or if you can align you orbits to cross and then divert in time, a bag of buckshot should do the job. :argue

I would say that scattering a bag of plastic pearls in a counter-orbit should do the trick against any satelite/space station - that's probably something many states can achive if they want to.

Concerning the railgun; the escape velocity of earth is around 11Km/s, and such a projectile would be subjected to massive drag. Doubt that a rail gun can do the job.


"Rods from God"
While I would guess that such a rod will hit earth at some 4000-5000 m/s and have huge kintetic energy, studies of meteor impacts show that the penetrating power probably is limited, which has to do with the huge energy involved which simply vaporizes much of the material on impact, not that you don't get a big bang. For comparison I think that a football seized iron meteor penetrates some 5 m into soil.