N747NA - pictures of a unique 747

[chucky]

NASA's SOFIA observatory, a modified 747SP (ex United, Pan Am), is visiting Ames this week, and I got to take a little tour of the aircraft yesterday. It's not often my career and my hobby come together like this, so I'm really geeking out over this. I figured I'd post some pictures here.

SOFIA is an infrared observatory - a 2.5 meter reflecting telescope that sits in the rear of the aircraft. The telescope compartment is unpressurized, and the telescope is mounted on a three-axis gimbal in the pressure bulkhead. Scientifically, the observatory is good for studying certain molecules that no other observatory can, and they've been taking science data for a while, but as far as I know nothing's been published yet (they're working on special issues of the Astrophysical Journal and possibly also Astronomy & Astrophysics, which is the reason nothing is out yet). This is not the sort of astronomy I do, so I really don't know much about the science.

 

[kimberlyanne546]

NASA's SOFIA observatory, a modified 747SP (ex United, Pan Am), is visiting Ames this week, and I got to take a little tour of the aircraft yesterday. It's not often my career and my hobby come together like this, so I'm really geeking out over this. I figured I'd post some pictures here.

SOFIA is an infrared observatory - a 2.5 meter reflecting telescope that sits in the rear of the aircraft. The telescope compartment is unpressurized, and the telescope is mounted on a three-axis gimbal in the pressure bulkhead. Scientifically, the observatory is good for studying certain molecules that no other observatory can, and they've been taking science data for a while, but as far as I know nothing's been published yet (they're working on special issues of the Astrophysical Journal and possibly also Astronomy & Astrophysics, which is the reason nothing is out yet). This is not the sort of astronomy I do, so I really don't know much about the science.

Where do they fly this plane? Or is it grounded?

 

[weilke]

Where do they fly this plane? Or is it grounded?

All over the place in long missions spanning about 1/2 the globe. They go wherever meteorological conditions and the angles they need towards their intended targets coincide.

 

[chucky]

The program is headquartered out of Ames, but the plane flies out of Palmdale.

 

[Skip Miller]

I read an article on the engineering that went into cutting such a large hole in a 747 and preventing the tail from twisting off. My google-fu is failing me, I couldn't locate it.

The telescope measures infrared light, and the equipment has to be as cold as possible to attenuate noise in the equipment. That's one reason they fly unpressurized with the telescope hardware exposed to the elements, or lack thereof.

Some more information on Sofia:

http://blog.seattlepi.com/aerospace/2011/04/07/boeing-747-based-observatory-studies-star-formation/

-Skip

 

[Cap'n Jack]

As mentioned, used for infrared (IR) studies. The plane lifts the telescope clear of most of the atmosphere so water vapor does't absorb the radiation they want to image. IR is absorbed and emitted when chemical bonds strech or bend and can be useful in identifying functional groups (groups of atoms, such as OH, NH, CH, and others) on molecules.

 

[weilke]

The telescope measures infrared light, and the equipment has to be as cold as possible to attenuate noise in the equipment. That's one reason they fly unpressurized with the telescope hardware exposed to the elements, or lack thereof.

Also, pretty much anything you could put between the scope and the elements to keep it pressurized would shield the faint infrared radiation they are trying to collect.

The scope is apparently quite sensitive to dust and soot. For the missions, they go into areas off the usual jet-routes and climb above the layers contaminated by air traffic.

 

[Richard]

Late last month they were looking for a pilot and a sensor operator. Requires relocation to PMD.

 

[Cap'n Jack]

Late last month they were looking for a pilot and a sensor operator. Requires relocation to PMD.

Not a long-term job. IIRC, the "mission" was for 20 years. I think they are most of the way through that time frame.

 

[chucky]

Not a long-term job. IIRC, the "mission" was for 20 years. I think they are most of the way through that time frame.

They've only been observing for a year or two. There's no such thing as a long term project right now at NASA, though. The last airborne observatory was decommissioned to ramp up funding for SOFIA, but with budgets being what they are, I don't think SOFIA (or anything else) is safe from being cannibalized to fund something of higher priority. If the James Webb Space Telescope can get put on the chopping block, anything can.

 

[Cap'n Jack]

They've only been observing for a year or two. There's no such thing as a long term project right now at NASA, though. The last airborne observatory was decommissioned to ramp up funding for SOFIA, but with budgets being what they are, I don't think SOFIA (or anything else) is safe from being cannibalized to fund something of higher priority. If the James Webb Space Telescope can get put on the chopping block, anything can.

Maybe I'm thinking of the old project- I thought SOFIA was planned for 20 years, and I seem to remember this project from some time back, but my memory is far from perfect.

 

[JohnAJohnson]

Maybe I'm thinking of the old project- I thought SOFIA was planned for 20 years, and I seem to remember this project from some time back, but my memory is far from perfect.

NASA flew a C-141 with a scope in it for many years.

 

[weilke]

NASA flew a C-141 with a scope in it for many years.

The scope on the C141 was 90cm or so, the sofia scope is 2.5m. There is also a lot they have done on the sensor side. I think it's simply the successor.

 

[chucky]

The scope on the C141 was 90cm or so, the sofia scope is 2.5m. There is also a lot they have done on the sensor side. I think it's simply the successor.

Yep. That plane sits on the ramp at Ames. SOFIA was pretty delayed, as I recall, and it may not have been much less than 20 years since they started the project, but I'm not sure. It doesn't have a lot of exposure in the astronomy community right now - my wife, who does astronomy that might benefit from SOFIA, didn't even realize it had started taking data. So they've got some work to do promoting the observatory to the community.

Edit - I've attached a picture where you can see that previous observatory, Kuiper, under SOFIA's wing.

 

[Richard]

Not a long-term job. IIRC, the "mission" was for 20 years. I think they are most of the way through that time frame.

Yeah but think of being able to say you flew a 747 in the flight levels with the window open.

 

[JohnAJohnson]

Yep. That plane sits on the ramp at Ames. SOFIA was pretty delayed, as I recall, and it may not have been much less than 20 years since they started the project, but I'm not sure...

I first saw the NASA 141 at Travis AFB in (if I remember correctly) 1973. I went out on the ramp to fix a compass problem and wow, an "N" number on the tail and a pretty blue paint scheme. Anyway, the crew chief (civilian guy) gave me the tour and talked a bit about the big cylinder thing in the cargo compartment just aft of the crew compartment, and all the video monitors and stations just aft of the scope. He said they mostly flew around at high altitudes in support of project Blue Book, looking for UFOs. He also said that if there was a nickel on the moon, you could read "In God We Trust" on those video monitors. Impressive for this young kid at the time.