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Satellites can be re-oriented into different orbital inclinations but that requires fuel and in the absence of a Shuttle fleet they cannot be refuelled. So des

Satellites can be re-oriented into different orbital inclinations but that requires fuel and in the absence of a Shuttle fleet they cannot be refuelled. So despite movie depictions they don't go swerving hither and thither to follow a camel up a mountain track. Such limited manoeuvring also requires planning and 90 minutes between passes. Lots of opportunity for bad guys to push their missile back into a hangar. An atmospheric aircraft can follow an arbitrary course to take in as many targets as required, can be rerouted on a moment's notice and can approach from unexpected vectors to catch the target out in the open.

ams6110 9y ago
Sure, but don't we have drones for that now? The high altitude spy planes (U2, SR-71) were mostly to prevent being shot down; surviving to return the film to base. Drones don't need to bring film back, and it's not such a big deal if a few of them are lost.
- saulrh 9y ago
  If it can be shot down, I think that it's probably safe to assume that it won't be able to see anything particularly interesting. I'd expect something like Groom Lake to be surrounded by an impenetrable wall of interceptors and SAM sites. Though I suppose that you could try to make your drones so cheap and in such volume that shooting them down becomes logistically and economically infeasible, but that's another strategy entirely.
  - mabbo 9y ago
    > I'd expect something like Groom Lake to be surrounded by an impenetrable wall of interceptors and SAM sites The whole idea of the SR-71 was that it went so fast that SAMs could just barely not catch up to it before they ran out of fuel. Any other plane couldn't outrun them, but the Blackbird? Well, Mach 3.4 will give you some breathing room.
    - astdb 9y ago
      The standard evasion tactic for SR-71 upon launched against was to simply accelerate.
      - deleted 9y ago
        [deleted]
      - Already__Taken 9y ago
        That would be the only option. It's not like you can turn much you'd pass out or snap the airframe. I imagine thought a little snake left/right might compromise getting the images that was the point of the mission.
        cryptonector 9y ago
        Apparently it could also turn pretty hard. Mind, it's turn radius was huge, but at mach 3.2 it still meant pulling a lot of g's.
    - pdelbarba 9y ago
      More to the point, it takes time to notice, track, lock and (in some cases) get approval to fire. That gives you seconds to minutes to not only fire but for the missile to reach the intercept point. Missiles and radar tend to operate in a "bubble". Even with the Russian S200 system at 190 miles range, the time you spend in that "bubble" when you're at 70k ft is not often long enough to do anything. That also assumes the aircraft directly overflies the battery. You can play games like pointing the camera sideways and observing from an angle if you know there are going to be angry people with guns nearby.
    - burfog 9y ago
      Mach 3.4 was also fast enough that early radar systems couldn't track it. The plane would move far enough between radar pulses that it got filtered out as noise.
    - mikeash 9y ago
      The state of the art advances. There are SAMs today that can shoot down ICBMs. I would guess that one reason the SR-71 was retired, besides the official line that it was expensive and made obsolete by satellites, is that it was no longer invulnerable as it had been when it was new.
- IndrekR 9y ago
  Just speculating here on two points: - There is no real need for SR-72 to be manned on all flights; - Hypersonic plane would be very good for small (2m wingspan) drone delivery behind the enemy lines fast (in half an hour). This was already a concept with M-21/D-21, but now the drone part can be much smaller and one plane could carry more than 4 of those. Satellites are quite limited when you need to make fast decisions. Hypersonic plane will move about 7 times slower than an optical recce satellite, yet it can maneuver very fast if you need to relocate the imaging area and can get at least 10 times closer to the target. Instruments can be selected/improved even after the first flight of the plane -- not true for the satellites.
jfoutz 9y ago
I always imagined spy satellites in a 'string of pearls' kind of configuration. Rather than having 1 in some specific orbit, have 4 or more in the same orbit. your 90 minute return time gets cut to ~20 minutes or less. Obviously, i have no information either way.
- nradov 9y ago
  There's no need to imagine. The quantity and orbits of spy satellites are public knowledge since there's no way to hide anything in space. The exact capabilities of each satellite are classified but but we can guess how good their sensors are just based on physics. Currently it costs so much to build and launch a spy satellite that we can't afford to put a bunch of them strung out in a single orbit, but maybe that will become practical eventually as launch costs decline.
  - knz 9y ago
    > The quantity and orbits of spy satellites are public knowledge since there's no way to hide anything in space. The "Misty" satellites came up on HN last week related to the SpaceX launch and failure. https://en.m.wikipedia.org/wiki/Misty_(satellite) https://en.m.wikipedia.org/wiki/Misty_(satellite) http://www.armaghplanet.com/blog/the-real-mystery-satellites.html http://www.armaghplanet.com/blog/the-real-mystery-satellites... "A week after launch, reports were released from the Soviets that six bits of debris had been detected suggesting an explosion had occurred. The Pentagon announced that any debris would decay after six weeks. The amateur astronomers and observers that were tracking this object only catalogued five out of the six pieces. Six months later an unidentified satellite was discovered in orbit on a similar trajectory to that of the classified payload was released, leading the satellite spotters to suspect it was the missing piece, nick-named Misty. However a couple of noticeable manoeuvres later, Misty disappeared again. Perhaps the ‘explosion’ was a decoy to put Misty into place unbeknownst to the Russians."
- robszumski 9y ago
  Planet is doing this with many satellites today. They are much smaller than DoD projects so it's much cheaper. Here's a diagram of their style orbit: https://www.planet.com/docs/spec-sheets/spacecraft-ops/monitoring.jpg https://www.planet.com/docs/spec-sheets/spacecraft-ops/monit...
vpribish 9y ago
that's a weirdly specific shuttle refueling point, dingaling. satellite servicing of any kind was very rarely attempted much less regular refueling. We can and do change orbits using onboard fuel without ever refueling - sure it's limited. Saying the shuttles supported refueling and hence maneuvering spy satellites are no longer a thing is very far from reality.
- vkou 9y ago
  1. The Space Shuttle flew a large number of lengthy, classified missions. 2. The Space Shuttle suffered from many costly design compromises due to its excessively large hangar bay. Given #1 and #2, there are four likely kinds of classified missions that the Space Shuttle undertook. 1. Stealing Russian military satellites. 2. Returning American military satellites to Earth. 3. Launching American military satellites into unpredictable orbits. 4. Refueling American military satellites, which allowed them to change to a new, unpredictable orbit. It's entirely possible that the Space Shuttle only engaged in some of these tasks... But it's difficult to conclude that given the very odd design of the space shuttle, and the very lengthy missions that it undertook, that no satellite servicing/orbital shenanigans took place. Yes, satellites can change orbits using on-board fuel reserves, but due to the tyranny of the rocket equation, those reserves are limited - and are unlikely to allow a very large inclination change (Inclination changes are incredibly fuel-expensive.)
  - nradov 9y ago
    The Space Shuttle certainly didn't steal any Soviet satellites. The Soviets had radar too. It's physically impossible to do anything like that in space without getting caught. Furthermore the Shuttle couldn't get higher than LEO so many satellites were simply out of its range. Likewise there is no such thing as an unpredictable orbit. Orbits are predictable, by definition. Any country with a good set of radars, telescopes, and IR sensors can find the exact orbit of every single satellite. The Space Shuttle was certainly used for launching American military satellites into regular predictable orbits. They might have done a refueling mission at some point as a proof-of-concept but even that seems unlikely considering that it's always cheaper to just build and launch a new satellite.
valuearb 9y ago
What's the point of having people in this?
- mulmen 9y ago
  To operate it.
mr_overalls 9y ago
> in the absence of a Shuttle fleet they cannot be refuelled. Judging by the publicly-released payload specs for the DoD-operated Boeing X-37 spaceplane, it should be able to deliver about 2000+ L of hydrazine, compressed Xenon, or other suitable fuel in a single launch. Edit: It looks like DARPA has been experimenting with "space gas station" experiments since at least 2007. https://www.space.com/3644-prototype-satellites-demonstrate-orbit-refueling.html https://www.space.com/3644-prototype-satellites-demonstrate-...
outworlder 9y ago
> Satellites can be re-oriented into different orbital inclinations but that requires fuel A LOT of fuel. So much so that even if lifetime wasn't an issue, it makes more sense to launch additional satellites in the proper inclination, rather than moving one. I know that, in one instance, a company wanted to use the moon's gravity to change a satellite's inclination, as it was cheaper to all the way to the moon and back (and then circularize again). That maneuver seems to be patented, though.
- pdelbarba 9y ago
  Patents be damned, I use that in KSP from time to time. Can I claim prior art? If you're on a level orbit and you fly off to the moon, adjusting with a tiny bit of inclination so that instead of nearing the moon on the same plane but from above, you're suddenly in a highly inclined orbit on your way back. You can also use this to slow down/speed up depending on which side you approach.
- techdragon 9y ago
  Patent number/reference please? I’d love to use this as a test case in an orbital dynamics library I’m building.
  - msl 9y ago
    I am fairly sure that "US 6116545 A" [1] is the patent in question. [1] https://www.google.com/patents/US6116545 https://www.google.com/patents/US6116545
ForHackernews 9y ago
Yeah, but a low, slow, cheap drone has all those advantages anyway. There's no need for a hypersonic space plane.

ams6110 9y ago

Sure, but don't we have drones for that now? The high altitude spy planes (U2, SR-71) were mostly to prevent being shot down; surviving to return the film to base. Drones don't need to bring film back, and it's not such a big deal if a few of them are lost.

saulrh 9y ago
If it can be shot down, I think that it's probably safe to assume that it won't be able to see anything particularly interesting. I'd expect something like Groom Lake to be surrounded by an impenetrable wall of interceptors and SAM sites. Though I suppose that you could try to make your drones so cheap and in such volume that shooting them down becomes logistically and economically infeasible, but that's another strategy entirely.
- mabbo 9y ago
  > I'd expect something like Groom Lake to be surrounded by an impenetrable wall of interceptors and SAM sites The whole idea of the SR-71 was that it went so fast that SAMs could just barely not catch up to it before they ran out of fuel. Any other plane couldn't outrun them, but the Blackbird? Well, Mach 3.4 will give you some breathing room.
  - astdb 9y ago
    The standard evasion tactic for SR-71 upon launched against was to simply accelerate.
    - deleted 9y ago
      [deleted]
    - Already__Taken 9y ago
      That would be the only option. It's not like you can turn much you'd pass out or snap the airframe. I imagine thought a little snake left/right might compromise getting the images that was the point of the mission.
      - cryptonector 9y ago
        Apparently it could also turn pretty hard. Mind, it's turn radius was huge, but at mach 3.2 it still meant pulling a lot of g's.
  - pdelbarba 9y ago
    More to the point, it takes time to notice, track, lock and (in some cases) get approval to fire. That gives you seconds to minutes to not only fire but for the missile to reach the intercept point. Missiles and radar tend to operate in a "bubble". Even with the Russian S200 system at 190 miles range, the time you spend in that "bubble" when you're at 70k ft is not often long enough to do anything. That also assumes the aircraft directly overflies the battery. You can play games like pointing the camera sideways and observing from an angle if you know there are going to be angry people with guns nearby.
  - burfog 9y ago
    Mach 3.4 was also fast enough that early radar systems couldn't track it. The plane would move far enough between radar pulses that it got filtered out as noise.
  - mikeash 9y ago
    The state of the art advances. There are SAMs today that can shoot down ICBMs. I would guess that one reason the SR-71 was retired, besides the official line that it was expensive and made obsolete by satellites, is that it was no longer invulnerable as it had been when it was new.
IndrekR 9y ago
Just speculating here on two points: - There is no real need for SR-72 to be manned on all flights; - Hypersonic plane would be very good for small (2m wingspan) drone delivery behind the enemy lines fast (in half an hour). This was already a concept with M-21/D-21, but now the drone part can be much smaller and one plane could carry more than 4 of those. Satellites are quite limited when you need to make fast decisions. Hypersonic plane will move about 7 times slower than an optical recce satellite, yet it can maneuver very fast if you need to relocate the imaging area and can get at least 10 times closer to the target. Instruments can be selected/improved even after the first flight of the plane -- not true for the satellites.

jfoutz 9y ago

I always imagined spy satellites in a 'string of pearls' kind of configuration. Rather than having 1 in some specific orbit, have 4 or more in the same orbit. your 90 minute return time gets cut to ~20 minutes or less. Obviously, i have no information either way.

nradov 9y ago
There's no need to imagine. The quantity and orbits of spy satellites are public knowledge since there's no way to hide anything in space. The exact capabilities of each satellite are classified but but we can guess how good their sensors are just based on physics. Currently it costs so much to build and launch a spy satellite that we can't afford to put a bunch of them strung out in a single orbit, but maybe that will become practical eventually as launch costs decline.
- knz 9y ago
  > The quantity and orbits of spy satellites are public knowledge since there's no way to hide anything in space. The "Misty" satellites came up on HN last week related to the SpaceX launch and failure. https://en.m.wikipedia.org/wiki/Misty_(satellite) https://en.m.wikipedia.org/wiki/Misty_(satellite) http://www.armaghplanet.com/blog/the-real-mystery-satellites.html http://www.armaghplanet.com/blog/the-real-mystery-satellites... "A week after launch, reports were released from the Soviets that six bits of debris had been detected suggesting an explosion had occurred. The Pentagon announced that any debris would decay after six weeks. The amateur astronomers and observers that were tracking this object only catalogued five out of the six pieces. Six months later an unidentified satellite was discovered in orbit on a similar trajectory to that of the classified payload was released, leading the satellite spotters to suspect it was the missing piece, nick-named Misty. However a couple of noticeable manoeuvres later, Misty disappeared again. Perhaps the ‘explosion’ was a decoy to put Misty into place unbeknownst to the Russians."
robszumski 9y ago
Planet is doing this with many satellites today. They are much smaller than DoD projects so it's much cheaper. Here's a diagram of their style orbit: https://www.planet.com/docs/spec-sheets/spacecraft-ops/monitoring.jpg https://www.planet.com/docs/spec-sheets/spacecraft-ops/monit...

vpribish 9y ago

that's a weirdly specific shuttle refueling point, dingaling. satellite servicing of any kind was very rarely attempted much less regular refueling. We can and do change orbits using onboard fuel without ever refueling - sure it's limited. Saying the shuttles supported refueling and hence maneuvering spy satellites are no longer a thing is very far from reality.

vkou 9y ago
1. The Space Shuttle flew a large number of lengthy, classified missions. 2. The Space Shuttle suffered from many costly design compromises due to its excessively large hangar bay. Given #1 and #2, there are four likely kinds of classified missions that the Space Shuttle undertook. 1. Stealing Russian military satellites. 2. Returning American military satellites to Earth. 3. Launching American military satellites into unpredictable orbits. 4. Refueling American military satellites, which allowed them to change to a new, unpredictable orbit. It's entirely possible that the Space Shuttle only engaged in some of these tasks... But it's difficult to conclude that given the very odd design of the space shuttle, and the very lengthy missions that it undertook, that no satellite servicing/orbital shenanigans took place. Yes, satellites can change orbits using on-board fuel reserves, but due to the tyranny of the rocket equation, those reserves are limited - and are unlikely to allow a very large inclination change (Inclination changes are incredibly fuel-expensive.)
- nradov 9y ago
  The Space Shuttle certainly didn't steal any Soviet satellites. The Soviets had radar too. It's physically impossible to do anything like that in space without getting caught. Furthermore the Shuttle couldn't get higher than LEO so many satellites were simply out of its range. Likewise there is no such thing as an unpredictable orbit. Orbits are predictable, by definition. Any country with a good set of radars, telescopes, and IR sensors can find the exact orbit of every single satellite. The Space Shuttle was certainly used for launching American military satellites into regular predictable orbits. They might have done a refueling mission at some point as a proof-of-concept but even that seems unlikely considering that it's always cheaper to just build and launch a new satellite.

valuearb 9y ago

What's the point of having people in this?

mulmen 9y ago
To operate it.

mr_overalls 9y ago

> in the absence of a Shuttle fleet they cannot be refuelled. Judging by the publicly-released payload specs for the DoD-operated Boeing X-37 spaceplane, it should be able to deliver about 2000+ L of hydrazine, compressed Xenon, or other suitable fuel in a single launch. Edit: It looks like DARPA has been experimenting with "space gas station" experiments since at least 2007. https://www.space.com/3644-prototype-satellites-demonstrate-orbit-refueling.html https://www.space.com/3644-prototype-satellites-demonstrate-...

outworlder 9y ago

> Satellites can be re-oriented into different orbital inclinations but that requires fuel A LOT of fuel. So much so that even if lifetime wasn't an issue, it makes more sense to launch additional satellites in the proper inclination, rather than moving one. I know that, in one instance, a company wanted to use the moon's gravity to change a satellite's inclination, as it was cheaper to all the way to the moon and back (and then circularize again). That maneuver seems to be patented, though.

pdelbarba 9y ago
Patents be damned, I use that in KSP from time to time. Can I claim prior art? If you're on a level orbit and you fly off to the moon, adjusting with a tiny bit of inclination so that instead of nearing the moon on the same plane but from above, you're suddenly in a highly inclined orbit on your way back. You can also use this to slow down/speed up depending on which side you approach.
techdragon 9y ago
Patent number/reference please? I’d love to use this as a test case in an orbital dynamics library I’m building.
- msl 9y ago
  I am fairly sure that "US 6116545 A" [1] is the patent in question. [1] https://www.google.com/patents/US6116545 https://www.google.com/patents/US6116545

ForHackernews 9y ago

Yeah, but a low, slow, cheap drone has all those advantages anyway. There's no need for a hypersonic space plane.