12 Miles High: An Integrated Airship-Radar Is on the Horizon

[OKIsItJustMe]

http://www.mitre.org/news/digest/defense_intelligence/03_10/isis.html

12 Miles High: An Integrated Airship-Radar Is on the Horizon

March 2010

Editor's note: This article originally appeared in MITRE's employee publication, MITRE Matters.

A high-altitude reconnaissance and surveillance platform, the Integrated Sensor Is the Structure (ISIS) is a tall order—literally. The unmanned airship, which measures 450 feet in length, will soar 70,000 feet above Earth for up to 10 years. It's not exactly the Goodyear blimp, and—in case you haven't guessed already—it's designed to cover more than the Super Bowl.

ISIS, like all blimps, is filled with helium, but comparisons end there. Hovering in the stratosphere, safely out of range of most surface-to-air or air-to-air missiles, ISIS is designed to provide unsurpassed situational awareness with a surveillance range of 187 miles for individuals on the ground and 373 miles for advanced cruise missiles.

From its parking space in the heavens, ISIS will have an excellent vantage point for surveillance and tracking. For example, objects on the ground can't disappear from the view of ISIS behind trees or mountains. "It's not just point coverage, like a view of a city," says Perry Hamlyn, head of MITRE's Advanced Wireless Electronics department. "You can see significant areas of an entire region."

...

Energy generation and storage present another significant design challenge. ISIS includes novel power systems for the airship that are based on solar-regenerative power. Solar cells collect energy from the sun and create hydrogen and oxygen from water during the day. At night, the hydrogen and oxygen are recombined in the fuel cell, which releases energy that allows the airship to operate after dark. Fuel cells were chosen for energy storage since they offer the best mass-to-energy storage ratio when compared to batteries and other storage systems.

"We developed solar availability and system energy models, performed trade studies, and provided technical support to ISIS from the early concept phase all the way up to the current demonstration phase," says Hamlyn. "Throughout the program, we have been helping the contractors and the government ensure the technical feasibility of the project."

...

[izquierdista]

1. Ten years, my ass...

We'll see what the next meteor shower has to say about this. :rofl:

[OKIsItJustMe]

4. You mean like the ones that bring down 747's all the time?

Or, like the one's which brought down the International Space Station?

[izquierdista]

9. Maybe you missed this

"significantly reduced fabric mass"

As far as I know, the ISS and 747s are built with something stronger than wet Kleenex.

[OKIsItJustMe]

10. I guess they probably aren't aware of the hazard

Or, maybe they are.

http://www.americanheritage.com/articles/magazine/it/2007/1/2007_1_38.shtml

The Inflatable Satellite

To build a communications satellite, NASA engineers fell back on humanity’s oldest flight technology

By Nick D’Alto

...

The balloon’s skin was made from dimensionally stable polyethylene terephthalate—better known as Mylar—.0005 inch thick (“half as thick as the cellophane from a cigarette pack,” as it was often described). In 1959 Mylar was most familiar to consumers for its use in frozen-food pouches that could be dropped into boiling water; it was also used for recording tape. NASA researchers tested dozens of materials, but only Mylar met the severe criteria, which included holding together at temperatures ranging from 300 degrees Fahrenheit in direct sunlight to -80 degrees in the earth’s shadow.

...

Even in the near-emptiness of outer space, the fragile ball faced dangers. On August 14 it survived a meteor shower. The orbit had been chosen so that the balloon would spend its first week and a half in constant sunlight, and when it passed into the earth’s shadow for the first time, observers held their breath. Robbed of the sun’s heat, the balloon’s gas might resolidify, and it was an open question whether the balloon might grow misshapen or even burst on subsequent reinflation. These fears proved groundless.

The seemingly frail balloon proved remarkably durable. Though “wrinkled like a prune” (according to press reports) by the tons of micrometeorites that hit, and eventually punctured, its thin skin, the weary traveler kept flying, broadcasting the first television pictures by satellite (images of a rodeo cowboy and a trained seal) in April 1962.

...

[Ready4Change]

19. VAST difference in altitudes

The proposed blimp/radar would be at 70,000 feet, roughly 13 miles up. That's still well under a LOT of atmosphere. Weather balloons often climb twice as high, and airplanes such as the SR-71 or can sustain level flight at 100,000 feet. To do that, both weather balloons and the 2 aircraft REQUIRE a decent amount of air. Air that causes micro meteorites to burn up tens or hundreds of thousands of feet higher.

'Space' is typically defined as starting at 62 miles, roughly 325,000 feet up. At that point you are 'mostly' in a vacuum. But satellites don't orbit there, because there are still atmospheric traces which, over time, will slow down an orbiting body enough to drop it out of orbit. So satellites (and other orbiting bodies, like the ISS) are almost always above 200 miles up, and often several thousand miles up. Really the only reason to have a satellite down below 400 is if you'd like it serviced by the Space Shuttle, or if you don't intend for it to be in space long.

Point is, at 13 miles (70,000 feet) micrometeorites are a minor risk. Mechanical/tech failures, storm stresses on the cable, hell, even the hazards this would impose on general aviation navigation, are far more weighty issues than space debris.

[Posteritatis]

13. A Chobham-armored airliner wouldn't be proof against meteorites

That said, the next plane that gets tagged with one will be the first to have been.

[Dead_Parrot]

2. Integrated Sensor Is the Structure?

Remember kids, never attempt a cool backronym before 4 cups of coffee, or after 4 pints of beer.

[OKIsItJustMe]

3. Actually, I'd prefer people avoided "backronyms" entirely

Honestly, did someone say, "Let's see, what would 'L-A-S-E-R' stand for?"

[Dead_Parrot]

5. Maybe they were trying to avoid "airship-radar surveillance experiment" at any cost. nt

[OKIsItJustMe]

6. This is an American airship buddy!

We only use English bacronyms. (OK, so maybe a few transliterated Egyptian ones, but that's it.)

[Dead_Parrot]

7. fair enough...

Airship surveillance structure with integrated power experiment.

[OKIsItJustMe]

8. That's more like it n/t

[eppur_se_muova]

12. You're pretty good at that, LOL! nt

[eppur_se_muova]

11. Actually, it was named in analogy to the maser.

And the acronym spells out what it does quite straightforwardly -- amplification by stimulated emission.

But I do detest politically motivated acronyms in which it becomes obvious that more effort was devoted to the acronym than to implementing the program, so I'm not in total disagreement.

[OKIsItJustMe]

15. Yes, I remembered that shortly after posting

But, then more people have heard of a LASER than have heard of MASER (also an acronym.)

In the 70's, I was outraged when I saw in a dictionary, LAZER listed as an alternate spelling for LASER. ("Alternate spelling!? What does the 'Z' stand for!?")

[Dead_Parrot]

16. Ztimulated, obviously

A more interesting question is how do you pronounce it?
:shrug:

[OKIsItJustMe]

17. How do you pronounce it?

Well, the same way I pronounce "LASER."

[eppur_se_muova]

18. I always thought it was mildly amusing that the most general case would be ...

ElectroMagnetic Radiation Ampli... i.e. ERASER.

Though having the word radiation appear twice is kinda clunky. :( Always a fly in the swill somewhere.

[Posteritatis]

14. I think they should take it a step further and have all acronyms be recursive. (nt)

[conscious evolution]

20. They have had similar blimps

along the US-Mexican border for decades.
Take a look at the FAA's Pheonix Sectional map near the Fort Huachuca/Bisbee area.
http://skyvector.com/