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Russian Physicists Solve Radio Black-Out Problem for Re-Entering Spacecraft

technologyreview.com

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Re: Russian Physicists Solve Radio Black-Out Problem for Re-Entering Spacecraft

#21

Post by fish2000 »

igravious wrote: post #4

That should read Theoretically Solve but I admire the ingenuity nonetheless and hope that the road from theory to practice is short and uneventful. A shame this hack has military applications, it would be nice if every now and again scientists patented their discoveries and precluded military use in doing so. [ Please don't downvote me for expressing this sentiment :) ]

The article says that one of the potential military applications would be the ability to disarm or redirect a weapon as it reenters the atmosphere -- Having taken the same topical look at the article that you have, I am not sure why you think that is a categorically bad thing to implement, from any standpoint. I mean, you could make the case that having that capacity will make the fingers that rest on the big red buttons all the itchier... if you wanted to be all ad hominem about things. I for one think that gapingly general fiat mandates like the one you propose are just as potentially damaging as any weapon.

Re: Russian Physicists Solve Radio Black-Out Problem for Re-Entering Spacecraft

#22

Post by chronomex »

pavel_lishin wrote: post #16

Anyone else see a weird font used for double-F's? http://i.imgur.com/EpolQ.png

The document uses a ligature ( http://www.fileformat.info/info/unicode/char/fb00/index.htm ) for ff. Apparently the font your browser uses by default doesn't have it. Some font replacement algorithm decided that the script font you're seeing is the closest! :-)

Re: Russian Physicists Solve Radio Black-Out Problem for Re-Entering Spacecraft

#23

Post by dstorrs »

elwin wrote: post #18
eps wrote: post #15

This might be a completely dumb idea and it must've been explored before, but how about attaching the antenna to a string and trailing it behind the ship at a considerable distance to clear the extent of the plasma shield. Is it that no string is strong or plasma-resistant enough?

When re-entering, spacecraft are being decelerated, so anything towed behind the spacecraft will catch up with it. A rigid pole might work.

They mention this in the article, where they talk about extending an aerial out past the plasma sheath. They then say "this allows communication until the aerial ablates."

Re: Russian Physicists Solve Radio Black-Out Problem for Re-Entering Spacecraft

#24

Post by dstorrs »

One thing they did not mention is that this solves the primary problem with orbital crowbars (fictionally called "Rods from God", "Thor", KEWs, and various other things). You could drop a kinetic warhead (basically a crowbar) from orbit to kill a tank / bunker / whatever, but you could also use them for a variety of peactime missions such as mining, emergency flood control (digging drainage ditches, causing controlled landslides), etc.

Each crowbar would need some sort of minimal steering system to account for atmospheric turbulence. This steering can't be locally controlled because the device can't see past the plasma sheath. It can't be remote controlled because the plasma sheath stops transmissions. With this new "plasma aerial" technology, you could steer each crowbar individually from the launcher platform.

Re: Russian Physicists Solve Radio Black-Out Problem for Re-Entering Spacecraft

#25

Post by igravious »

jerf wrote: post #13
igravious wrote: post #4

That should read Theoretically Solve but I admire the ingenuity nonetheless and hope that the road from theory to practice is short and uneventful. A shame this hack has military applications, it would be nice if every now and again scientists patented their discoveries and precluded military use in doing so. [ Please don't downvote me for expressing this sentiment :) ]

Pretty hard to lock down a communications technology to "no military use". What are they going to do, ask pretty please don't do that with a cherry on top?

I know, right?! Like I said elsewhere, I'm probably letting the warm fuzzies of the holiday season get the better of me.

Is there even any precedent for this? Also, I seem to remember a quote from the mathematician Hardy boasting that he loved working in pure number theory because it had no application (military or otherwise) to the real world. Fast forward 50 years and pure number theory is widely used in encryption technologies ... so you just never know.

Anyway, and this might be cynical but a system that is used to imposing its will down the barrel of a gun will surely just take what they want regardless of the prohibitions.

I am reminded of the blessing that accompanies the public domain Sqlite. http://www.sqlite.org/different.html

  May you do good and not evil
  May you find forgiveness for yourself and forgive others
  May you share freely, never taking more than you give.
Evil is such a comic book superhero word nowadays but I wonder how many times Sqlite has been put to nefarious ends.

Re: Russian Physicists Solve Radio Black-Out Problem for Re-Entering Spacecraft

#26

Post by ortusdux »

elwin wrote: post #18
eps wrote: post #15

This might be a completely dumb idea and it must've been explored before, but how about attaching the antenna to a string and trailing it behind the ship at a considerable distance to clear the extent of the plasma shield. Is it that no string is strong or plasma-resistant enough?

When re-entering, spacecraft are being decelerated, so anything towed behind the spacecraft will catch up with it. A rigid pole might work.

It would seem to me that any antenna that extends outside the 'plasma bubble' would still be traveling at the same speeds and subject to the same problems as the shuttle.

Re: Russian Physicists Solve Radio Black-Out Problem for Re-Entering Spacecraft

#27

Post by gvb »

Trivia: the space shuttle avoids the blackout by its shape, which allows it to communicate upward to the TDRSS satellites.

http://en.wikipedia.org/wiki/Communications_blackout#Reentry...

"[T]he Shuttle can communicate with a Tracking and Data Relay Satellite during re-entry. This is because the shape of the Shuttle creates a "hole" in the ionized air envelope, at the tail end of the craft, through which it can communicate upwards to a satellite in orbit and thence to a ground station."

Re: Russian Physicists Solve Radio Black-Out Problem for Re-Entering Spacecraft

#28

Post by CamperBob »

igravious wrote: post #4

That should read Theoretically Solve but I admire the ingenuity nonetheless and hope that the road from theory to practice is short and uneventful. A shame this hack has military applications, it would be nice if every now and again scientists patented their discoveries and precluded military use in doing so. [ Please don't downvote me for expressing this sentiment :) ]

This is a silly and naive sentiment, akin to "This new factoring algorithm has DRM-breaking applications. We'd better outlaw it."

Downvoted accordingly.

Re: Russian Physicists Solve Radio Black-Out Problem for Re-Entering Spacecraft

#29

Post by rbanffy »

igravious wrote: post #8
viraptor wrote: post #5

Earlier quoted context omitted.

I thought there was a clause making all technology available for national defence, regardless of patents... but can't find the source. Anyone?

That may be true in the US but what about in other jurisdictions? I mean doctor's have the Hippocrates oath of do no harm to the patient but (and not to come over all tree-hugging peacenik like) why do chemists/bioengineers/physicists not have a similar oath with respect to the our species or other species in general or the planet in its entirety? But I guess the scientists do the theorizing and the engineers and cod…

> That may be true in the US but what about in other jurisdictions?

I think that could be "the rule of the bigger gun". It's hard to argue with the guy who drives a tank across your lawn.

And preventing military use is a bad idea. The military are not always in offensive roles. And they are not automatically wrong when they use the force.

Re: Russian Physicists Solve Radio Black-Out Problem for Re-Entering Spacecraft

#30

Post by rbanffy »

sp332 wrote: post #14
igravious wrote: post #8

Earlier quoted context omitted.

That may be true in the US but what about in other jurisdictions? I mean doctor's have the Hippocrates oath of do no harm to the patient but (and not to come over all tree-hugging peacenik like) why do chemists/bioengineers/physicists not have a similar oath with respect to the our species or other species in general or the planet in its entirety? But I guess the scientists do the theorizing and the engineers and cod…

In Canada, there is a Ritual Calling of the Engineer, which has an "Obligation" which is not exactly an oath. http://en.wikipedia.org/wiki/The_Ritual_of_the_Calling_of_an... I'll paste the text here if I can find it.

It's a beautiful tradition. On my graduation all soon-to-be engineer colleagues also made a solemn promise more or less like the ones other engineers take in other countries and schools.

I also like the idea of passing the iron rings down through generations of new engineers. In Brazil we don't. It reminds the ones new to the career that others came before them and that others will come after them and of the obligations we share. That's one thing many of us forget much too frequently.

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