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747 turned flying telescope takes off in Waco
Valley Press on ^ | Saturday, April 28, 2007. | ALLISON GATLIN

Posted on 04/28/2007 9:51:02 AM PDT by BenLurkin

A modified 747 airliner designed to carry an infrared telescope took its first flight Thursday, one of several checkout flights planned before it makes its way to a new home at NASA Dryden Flight Research Center at Edwards Air Force Base.

The Stratospheric Observatory for Infrared Astronomy, or SOFIA, consists of a 2½-meter in diameter infrared telescope mounted inside the 747 airliner, chosen for its ability to house the 45,000-pound telescope.

The long-range airliner is capable of remaining airborne for six hours at altitudes higher than 41,000 feet, above much of the atmospheric water vapor.

SOFIA will be used to study the universe in the infrared spectrum, as well as to develop observational techniques, instruments and for educational purposes.

Thursday's flight took place in Waco, Texas, where the airliner has undergone extensive modifications by L-3 Communications Integrated Systems. Dryden research pilot Gordon Fullerton commanded the flight crew.

The airliner is outfitted with 16-foot-high clamshell doors in the rear of the fuselage, which will open in flight to allow the telescope access to the sky.

The door is in two parts, a rigid upper portion that opens to expose the cavity, and a flexible lower portion attached to the telescope that moves up and down with the instrument.

The cavity itself is a cylindrical hole in the side of the aircraft, the largest ever intentionally cut into a working aircraft.

A bulkhead was installed forward of the cavity, in order to pressurize the rest of the aircraft cabin in flight. The telescope bay is unpressurized as it will be open to the outside when in use.

"Now we are into a body of work to try to finish development of the aircraft, to try to expand the working envelope," said John Carter, project manager for the platform at Dryden.

(Excerpt) Read more at avpress.com ...


TOPICS: US: California; US: Texas
KEYWORDS: 747; aerospace; aerospacevalley; allisongatlin; antelopevalley; boeing; edwardsafb; sofia

1 posted on 04/28/2007 9:51:12 AM PDT by BenLurkin
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To: BenLurkin

TTIUWP

2 posted on 04/28/2007 9:53:15 AM PDT by martin_fierro (< |:)~)
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To: martin_fierro

Thanks!


3 posted on 04/28/2007 9:54:00 AM PDT by BenLurkin
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To: BenLurkin; All
Pix here.
4 posted on 04/28/2007 9:55:42 AM PDT by dighton
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To: BenLurkin

My impression is that a flying aircraft vibrates, and a telescope better not vibrate if one wants to get sharp pictures, especially at longer exposures. Now, their IR telescope is heavy, and vibrationally isolating it from the body of the aircraft would be non-trivial.


5 posted on 04/28/2007 9:56:09 AM PDT by GSlob
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To: BenLurkin
The long-range airliner is capable of remaining airborne for six hours at altitudes higher than 41,000 feet, above much of the atmospheric water vapor.

Oh come on! A 747SP can cruise from LAX to SYD at up to 51,000 feet. That's a lot longer than six hours.

6 posted on 04/28/2007 9:58:24 AM PDT by Paleo Conservative
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To: BenLurkin
one of several checkout flights planned before it makes its way to a new home at NASA Dryden Flight Research Center at Edwards Air Force Base.

Where somebody will immediately assume it's transporting 50 tons of Cocaine the first time they see it in the air.

7 posted on 04/28/2007 10:07:34 AM PDT by Strategerist
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To: BenLurkin

8 posted on 04/28/2007 10:07:35 AM PDT by jws3sticks (Hillary can take a very long walk on a very short pier, anytime, and the sooner the better!)
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To: BenLurkin
I would have thought that an open hatch, at several hundred miles-per-hour, would generate a lot of turbulence in the instrument bay itself.

Guess that's why I'm not a NASA scientist....

9 posted on 04/28/2007 10:23:34 AM PDT by GoldCountryRedneck ("The American Indians found out what happens when you don't control immigration."- unknown)
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To: BenLurkin

This is the current version of the Kuiper. I was around it a lot when I worked for NASA. Flying observatories have been around for quite a while.


10 posted on 04/28/2007 10:37:56 AM PDT by ZGuy (This country will never fall from terrorists. It will fall from accepting social liberalism.)
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To: GSlob

“Now, their IR telescope is heavy, and vibrationally isolating it from the body of the aircraft would be non-trivial.”

Heavy is better for vibrational damping.


11 posted on 04/28/2007 11:21:09 AM PDT by FastCoyote
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To: Paleo Conservative

It’s possible that the weight of its payload is such that they have to limit the amount of fuel they can carry. It would be a trade off. The laws of physics don’t care what the load is, just how much there is of it.


12 posted on 04/28/2007 12:19:33 PM PDT by jwparkerjr
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To: Paleo Conservative

Not with a twenty-foot hole in it...


13 posted on 04/28/2007 12:25:20 PM PDT by patton (19yrs ... only 4,981yrs to go ;))
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To: FastCoyote

Tell it to aerial photographers who use gyroscopic stabilization rig in which the camera with its lens are mounted. The bigger the camera/lens, the bigger, more unwieldy, and heavier the stabilizing rig is.


14 posted on 04/28/2007 1:17:30 PM PDT by GSlob
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To: jwparkerjr
It’s possible that the weight of its payload is such that they have to limit the amount of fuel they can carry. It would be a trade off. The laws of physics don’t care what the load is, just how much there is of it.

I doubt it has anywhere near the normal load of a fully loaded 747SP. An SP had about the passenger capacity and range of a 777-200ER, so it could carry about 300 passengers. The open observatory door must cause a considerable amount of drag.

15 posted on 04/28/2007 1:31:52 PM PDT by Paleo Conservative
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To: GSlob

“The bigger the camera/lens, the bigger, more unwieldy, and heavier the stabilizing rig is.”

Obviously the weight of the dampening mechanism goes up, the question is in what proportion. Actually, both our answers are wrong. The vibration will be a function of how close the combined suspended mass-spring-damper system excitory frequency is to the input frequency. The input frequency in this case is dependent on the mass of the airplane, the spring constants of the airframe and suporting air, the dampening air friction and the vibrational energy inputs from the engines and air pressure and wind velocity fluctuations.

I think the easiest way to figure that out is to just stick a mass on a support and fly it for real.


16 posted on 04/28/2007 6:24:47 PM PDT by FastCoyote
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To: FastCoyote

If the supported thing is to remain stationary when the base vibrates with acceleration a, then the force acting on the supported body [to be dampened out] is F=ma, per Newton- directly proportional to the mass [of telescope]. Thus the size of dissipating system [within the same technology] is more or less proportional to the supported mass, mounting harness [with its mass] could be considered as a part of the supported body. For the several sizes of gyroscopic stabilization rigs it seems to bear out. The trouble with them was not so much their weight [747 would be able to handle it] as the general clumsiness and spatial requirements.


17 posted on 04/28/2007 6:47:49 PM PDT by GSlob
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To: BenLurkin
I had some friends on the project. Its an old UAL 747-SP that they in turn got from PanAm when they bought the PanAm Pacific routes for $900 million.

That was the best purchase they ever made IMO.

18 posted on 04/28/2007 7:03:21 PM PDT by RunningWolf (2-1 Cav 1975)
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To: RunningWolf

I wish them good luck and safe flying!


19 posted on 04/28/2007 7:09:45 PM PDT by BenLurkin
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To: BenLurkin
Yes I wish they had been able to design rollaway doors ala B24 style rather than Clamshells.
20 posted on 04/28/2007 7:13:17 PM PDT by RunningWolf (2-1 Cav 1975)
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To: GSlob

Friend of mine who was a solar astronomer did this about 30 years ago to follow a total eclipse (across Africa iirc), getting a chance to extend totality by many times over. Vibration didn’t seem to be a problem then.


21 posted on 04/28/2007 7:14:04 PM PDT by hinckley buzzard
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To: jws3sticks
Notice he has his leading edges down, maybe a few degrees of t/e flap also. I guess thats how they will fly it inorder to keep the airspeed as low as they can.
22 posted on 04/28/2007 7:16:41 PM PDT by RunningWolf (2-1 Cav 1975)
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To: RunningWolf
RW,

Great observation! Not being a pilot, it did not catch my eye. I am sure you are right.

Thanks for the posting.

I'll run it my a small plane pilot pal and I'm sure you hit the nail on the old head.

23 posted on 04/29/2007 8:00:42 PM PDT by jws3sticks (Hillary can take a very long walk on a very short pier, anytime, and the sooner the better!)
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