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Hypersonic Radio Black-Out Problem Solved
KentuckyFC writes "Russian physicists have come up with a new way to communicate with hypersonic vehicles surrounded by a sheath of plasma. Ordinarily, this plasma absorbs and reflects radio waves at communications frequencies, leading to a few tense minutes during the re-entry of manned vehicles such as the shuttle. However, the problem is even more acute for military vehicles such as ballistic missiles and hypersonic planes. Radio blackout prevents these vehicles from accessing GPS signals for navigation and does not allow them to be re-targeted or disarmed at the last minute. But a group of Russian physicists say they can get around this problem by turning the entire plasma sheath into a radio antenna. They point out that any incoming signal is both reflected and absorbed by the plasma. The reflected signal is lost but the absorbed energy sets up a resonating electric field at a certain depth within the plasma. In effect, this layer within the plasma acts like a radio antenna, receiving the signal. However, the signal cannot travel further through the plasma to the spacecraft."
First!
It is always nice to know that governments appreciate new ways to improve on killing.
Killing protects us. Killing saves lives. Killing is better than killing.
And there are some occasional non-killing spinoffs. Isn't that great?!!?! Never mind that space exploration can produce tons more spinoffs per dollar. It doesn't involve nearly as much killing, so screw that.
Second!
BTW is there yet a solution for CmdrTaco's micropenis problem?
Is this PC? Maybe use "slave out"? What do you think, Linda?
The SNR and BER of that scheme are going to suck.
Until the creation of the Tracking and Data Relay Satellite System, the Space Shuttle would, like Gemini, Mercury, Apollo, and others, endure a 30 minute long communications blackout before landing. However, the 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.
Does this mean my 3G data card will work when I travel hypersonically?
check my dubs --->
http://www.freepatentsonline.com/3758862.html
(except it's patented)...
I read the full summary. The last sentence that the signal cannot travel into the craft from the plasma. How is that solved?
The cause of, and solution to, all technological problems in the 23rd century.
At the end of TFA they give the original reference, a paper preprinted in 2007. One way to tell if this holds water is to see if other research groups have done follow-ups in the intervening three years.
Just one glitch-- you can transmit with a plasma antenna, but you can't receive worth a darn.
You see the plasma is a bunch of random electrical discharges and accelerated particles, which put out a strong wideband noise, quite a few orders of magnitude stronger than any signal you might wish to receive.
And what's the rush? Re-entry plasma is time-limited to just a handful of minutes. Astronauts should be able to get along without Wi-Fi for that long.
Well, I read the full introduction of the paper, and the conclusion, skipping only the detailed plasma physics models & calculations. They do mention the strategy of putting an antenna through the plasma which can last as long as one fuel tank before it ablates, but they instead propose that (more elegantly) a small commercially-available 3 kW high frequency klystron amplifier (a lot less power than the radar) be placed at the surface of the aircraft, where it will disrupt a very small region of the plasma in a manner that will scatter ~.7 - 2% of the original incoming signal (which will resonates in a layer of the plasma) back to the aircraft; that is enough power for a 5 m. antenna and a commercially-available high sensitivity GPS receiver to pick it up. There is an analogous explanation for outgoing signals. They account for quite a few confounding plasma effects, acknowledge that there are some others that can't be modeled so clearly (or maybe they didn't think of), but predict that getting the system to work would be a not-so-difficult engineering challenge.
My first thought was, "Boy, I hope all the space opera authors read this preprint: no more signal attenuation from the plasma engines in the atmosphere!" Now there is one more area in which reality is exceeding a certain segment of--rather soft--science fiction (that I am only familiar with--AHEM--because of Baen's visionary no-DRM any-format ebook policy).
What I find most interesting is what the article didn't say. Oh, there is a plasma surrounding hypersonic vehicles, thats true. But, dear reader, there is *also* a plasma around military aircraft that use plasma to jam radar. Its not just the oblique features of the aircraft that contribute to a low radar signature (or the turbine intake that contributes to a high radar signature). Military aircraft have used RAM (radar absorbing material) in the paint of these aircraft --basically the paint acts like very small radar absorbing cavities that allows radar in, and then it bounces around in the paint, slightly heating it, and not reflecting it. But besides these two methods of jamming radar, you can put a plasma (artificial St. Elmos Fire), around parts of the aircraft with a high signature, and as the article states, the EM radiation that is the radar pulse can't get through it, and can't reflect off it. So you are invisible. Now this article and the technology it describes solves re-entry radio blackouts, but also the military kind. Thanks for reading....
The standard argument against being able to remotely disarm missiles has been that including such a mechanism opens the door for the enemy potentially figuring out how to do it - it's not about the ability to communicate.
#DeleteChrome
Remote controlled drone vs. live pilot in the seat I concede that for now the pilot will likely win out.
what if it's 3 drones to one live pilot
what if it's 7
what about ten?
every day http://en.wikipedia.org/wiki/Special:Random
@MajorTom: We just started our re-entry...