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I thought rocket science was supposed to be bleeding edge? It is not. The main problem in space are the high energy particles. They penetrate everything (and I

I thought rocket science was supposed to be bleeding edge? It is not. The main problem in space are the high energy particles. They penetrate everything (and I mean everything, also metal, processors, they cause bit flips and can do a lot of harm). So a first priority objective is reliable (=tested) hardware. There is little tested hardware for obvious reasons. I work in ESAs Herschel project. Herschel runs on 16 MHz processors (Mega - not Giga!) - like your good old Atari St. You don't wan't to risk a 1 Billion Euro Spacecraft, because of one failing chip. The detectors of the instruments, of course, are another story. These are indeed bleeding edge. Their readout electronics on the other hand, good old stuff again. So the whole thing is a funny mixture of old but fool proof hardware combined with new developments.

Swizec 16y ago
Couldn't you just shield against high energy particles with a strong magnetic field like Earth does? Or would that be too heavy to lug around and/or too difficult to supply with enough energy?
- mironathetin 16y ago
  How should we do that? You would need superconducting coils on board and an extra 1000 liters of helium to cool the coils. Then run 200 Amperes through them. You see yourself... Earths magnetic field stretches far into space. So the particles have to be diverted from their original course only a little bit. Impossible to do that for a spacecraft. Magnetic field strength decreases with 1/(r to the power of 3). In fact, for a small spacecraft, there are only a few hits into the electronics per day. I know a funny story from an astronaut, who was on the ISS for a while. He told us, even with eyes closed at "night", he could see light flashes, when a particle was absorbed within his eyeball. Nice place out there...
- fhars 16y ago
  Another "simple" solution would be to surround the probe with a 5m thick shell of water, the protons in there will absorb most of the high enerqy particles. It might just make it a bit difficult to accelerate the whole contraption to escape velocity...
  - rbanffy 16y ago
    Well... A heavily shielded spacecraft could be built and launched from the Moon... Use regolith for shielding and a magnetic rail to launch. This way most of the mass will never have to be lifted from Earth and, still, you get a lot of shielding, as much as your rail can launch. But that is decades (a good couple of them, more like a dozen) away. And the rail itself would be so easy to weaponize the diplomatic nightmare required to build it would dwarf the technical difficulties.
    - krschultz 16y ago
      Eh, it wouldn't be great to weaponize. You'd have way too much warning. The prompt global strike using a submarine launched ICBM mounted with a convential warhead accomplishes everything you would want from space based weapons without your targets being able to track things as easily, yet the US doesn't do it becuase of fear it would spark diplomatic problems. There are plenty of weapon systems better than a mag rail on the moon that we don't use today already, we don't need more.
      - jerf 16y ago
        This is the "Moon is a Harsh Mistress" scenario. The people weaponizing it may not be the Earth-bound nation state, it may be the lunar residents themselves. By the time you can run a rail system like this you've got at least a small village up there, minimum. There's something to be said for just throwing rocks at your opponent, when your rocks have the equivalent of a small nuke in yield. They're hard to divert, there's no clever electronics tricks you can play to fool them into not detonating, it's like trying to divert a multi-ton bullet. Everything in space is a weapon, and anything capable of launching "interesting" spacecraft opens the bidding at "capable of destroying cities" and moves up from there.
        Splines 16y ago
        Reminds me of this clip from Mass Effect 2: http://www.youtube.com/watch?v=7GqqDCe4Yrs http://www.youtube.com/watch?v=7GqqDCe4Yrs

Swizec 16y ago

Couldn't you just shield against high energy particles with a strong magnetic field like Earth does? Or would that be too heavy to lug around and/or too difficult to supply with enough energy?

mironathetin 16y ago
How should we do that? You would need superconducting coils on board and an extra 1000 liters of helium to cool the coils. Then run 200 Amperes through them. You see yourself... Earths magnetic field stretches far into space. So the particles have to be diverted from their original course only a little bit. Impossible to do that for a spacecraft. Magnetic field strength decreases with 1/(r to the power of 3). In fact, for a small spacecraft, there are only a few hits into the electronics per day. I know a funny story from an astronaut, who was on the ISS for a while. He told us, even with eyes closed at "night", he could see light flashes, when a particle was absorbed within his eyeball. Nice place out there...
fhars 16y ago
Another "simple" solution would be to surround the probe with a 5m thick shell of water, the protons in there will absorb most of the high enerqy particles. It might just make it a bit difficult to accelerate the whole contraption to escape velocity...
- rbanffy 16y ago
  Well... A heavily shielded spacecraft could be built and launched from the Moon... Use regolith for shielding and a magnetic rail to launch. This way most of the mass will never have to be lifted from Earth and, still, you get a lot of shielding, as much as your rail can launch. But that is decades (a good couple of them, more like a dozen) away. And the rail itself would be so easy to weaponize the diplomatic nightmare required to build it would dwarf the technical difficulties.
  - krschultz 16y ago
    Eh, it wouldn't be great to weaponize. You'd have way too much warning. The prompt global strike using a submarine launched ICBM mounted with a convential warhead accomplishes everything you would want from space based weapons without your targets being able to track things as easily, yet the US doesn't do it becuase of fear it would spark diplomatic problems. There are plenty of weapon systems better than a mag rail on the moon that we don't use today already, we don't need more.
    - jerf 16y ago
      This is the "Moon is a Harsh Mistress" scenario. The people weaponizing it may not be the Earth-bound nation state, it may be the lunar residents themselves. By the time you can run a rail system like this you've got at least a small village up there, minimum. There's something to be said for just throwing rocks at your opponent, when your rocks have the equivalent of a small nuke in yield. They're hard to divert, there's no clever electronics tricks you can play to fool them into not detonating, it's like trying to divert a multi-ton bullet. Everything in space is a weapon, and anything capable of launching "interesting" spacecraft opens the bidding at "capable of destroying cities" and moves up from there.
      - Splines 16y ago
        Reminds me of this clip from Mass Effect 2: http://www.youtube.com/watch?v=7GqqDCe4Yrs http://www.youtube.com/watch?v=7GqqDCe4Yrs