Yes, I was wondering about those guys too, but I thought perhaps they each had the clout to have established their own (redundant, as per usual) launch test facility.
Score one for DOD efficiency.
Besides this there are two other unique things about the X-37B: (1) Extremely long on-orbit mission capability – over two years (2) Very large orbital maneuvering capability – about 3,100 meters/sec delta-V, vs the shuttle’s 300 meters/sec.
Most of the photos don’t clearly show the large fuselage volume dedicated to the orbital propulsion system and propellant. In this photo it is everything aft of the payload bay doors:
It is difficult to see an obvious mission need for those three coinciding features in one vehicle that justify the development and program support costs that couldn’t be satisfied more cheaply. E.g, if you need long duration space exposure testing, why the huge orbital delta-v capability? If it’s for reconnaissance, why take the payload hit of reusability? If it’s for sensor testing, why develop an entire vehicle just to return those? Gigantic spy satellites have been successfully developed for decades without all that:
Orion/Magnum: http://www.globalsecurity.org/space/systems/magnum.htm
Lacrosse radar imaging satellite: https://leaksource.files.wordpress.com/2015/04/lacrosse4.jpg
KH-9: https://airandspace.si.edu/sites/default/files/images/stories/F15-0088-2.jpg
US Air Force Space Command (AFSC) is a major command (MAJCOM) within the USAF. As part of the Department of Defense it is entirely separate from NASA, which is an independent agency that operates outside of the executive department structure. The mission of AFSC is one primarily of security and control of orbital space and US assets within it, including tracking space objects and debris by the Joint Space Operations Center (JSpOC). The mission of NASA is scientific research and exploration, including supporting Earth surveillance capability for NOAA/National Weather Survice and the US Geological Survey, basic astronautics and aeronautic research, as well as the more celebrated crewed orbital/lunar and uncrewed interplanetary missions. There is no overarching control of one by the other but they obviously work together or subordinate on projects as necessary given coincident interests or efforts, including the Space Shuttle flying classified DoD payloads and NASA flying its own missions on Air Force launch vehicles such as Titan, Delta, and Atlas.
The Defense Advanced Resarch Projects Agency (DARPA) is primarily a fudning conduit and coordinator for technology development. Most of the actual work is done by research universities or under contract to NASA centers, government research labs, and Federally Funded Research & Development Centers (FFRDC) such as Lawrence Livermore and Los Alamos National Labs or Jet Propulsion Labs (which, despite being a NASA center is actually an FFRDC managed by California Institute of Technology). DARPA itself doesn’t maintain any space flight or significant fabrication facilities.
I wouldn’t score too much, there. Each of the agencies maintains their own set of launch complexes and most of the equipment associated with them. The range (the tracking facilities, safety oversight, and other logistical functions) are shared, sometimes contentiously, but for the most part each user pays and often jealously retains their areas of operation. It makes sense that they are all on CCAFS because as the southeastern most part of the continential United States it is one of the few places really suitable for launching lower attitude space missions and testing suborbital launches. (The USAF tests ICBMs out of Vandenberg AFB on the West Coast because they need the additional range possible with the Pacific range, but originally did IRBM testing out of CCAFS.) NASA also has a launch site on Wallops Island, VA, for launching sounding rockets and smaller suborbital vehicles that can launch at higher attitudes (trajectory generally crossing over the horn of Africa); there is also a USN radar test facility coincident which provides some tracking capability.
Stranger
Date: “rev. 2006”
Things I learned from that sheet:
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I, for one, would consider it an act of lèse-majesté humain for fuel cells to use a higher grade of O2 than my lungs, and will not order from a place with such bad atmosphere as Mims, Fla. I mean, at least I’ve heard of Orlando.
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It was neat to find more-real-life-scale figures for amounts of some of the fuels and other fluids used in operations.
When I worked at Edwards, there was a hydrazine leak from an F-16, and several people were exposed. The way people talked, it sounded like guaranteed liver cancer. Probably hyperbolic, but I’d definitely want a hazmat suit.
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[what’s the word again for “most efficient fuel” (disregarding application difficulties): “energy density?”]
I can think of a number of different mission requirements which could use this capability. Large surveillance satellites were a boon to intelligence analysts having to rely on irregular surveillance overflight photos, allowing regular access to images of potential missile or other weapon development sites, logistical facilities, et cetera, without concern of being shot down, but they require massive, expensive, and often delicate optics, and repositioning them often takes either a long period of intermediate burns or uses up lifespan on their limited on-station propellant.
But practically speaking, I think this vehicle–which was originally a DARPA program operated by NASA–is a test bed for future space surveillance and orbital operations technology, including testing methods of protection of space assets from interference or harm by a belligerent party. People seem impressed by the Chinese crewed space program’s goals of a long duration space station and eventual Lunar station, but what they have been doing in the space warfare arena is more concerning yet, insofar as they appear to understand better than anyone that the next battlefield is going to be defined by access to orbital space and protection of space assets.
Stranger
Read it and weep, from the CDC. Specifically on touching the stuff, let alone breathing it, but it’s a good start and has a ton of research notes.
Not hyperbole. Hydrazine is highly bioreactive and is classified as a probable human carcinogen (it isn’t considered a “known carcinogen” just because most people exposed to measureable levels of hydrazine usually die of other causes). What the safety people tell is if you smell the “dead fish aroma” you should run upwind without mentioning that if you’re able to smell that much you are probably going to be coughing up the liquified remains of your lungs by this time tomorrow. Hydrazine is not something to fuck around with.
We usually talk about fuel efficiencies in terms of specific impulse, which is the momentum change per unit mass of propellant. The actual performance of a propellant depends upon features of the type of engine or rocket it is operating in, but chemical propellants have a maximum possible specific impulse based upon the heat of combustion and resulting mass of the products. There are, however, other factors which govern selecting a propellant for a specific application, such as the volumetric energy density (how much tankage it takes per unit energy) or density impulse, effective exhaust velocity in atmosphere versus vacuum performance, and storability. The nice properties of molecular hydrazine and nitrogen tetraoxide for long term use is that it is thermally stable, does not auto-react except in the presence of a catalyst, and is hypergolic (automatically ignites when catalyzed) even though its performance is unspectacular (sea level I[SUB]sp[/SUB]~285 s versus almost I[SUB]sp[/SUB]~400 s for LH[SUB]2[/SUB]/LOX).
Stranger
:eek: I’m glad I was in Mission Control!
It’s been decades, but I think one of my coworkers was exposed. Or at least at the scene. I don’t remember her name, and never heard if she had any health problems.
Hydrazine is so dangerous that an internal debate over this was significantly responsible for the failed Soviet manned lunar program. Soviet space chief Sergei Korolev called hypergolic propellants “devil’s venom”, and preferred cryogenic propellants. However head engine designer Valentin Glushko liked hypergolics. A constant debate over this led to Glushko refusing to design cryogenic engines for the Soviet N1 (their Saturn V). Korolev’s only recourse was for less-experienced engineers to design smaller cryogenic engines for the N1, which never worked right. This is extensively documented in the book “Challenge to Apollo”: http://a.co/bvy7dsl
For anyone wanting more info on the safety factors and complications of handling various liquid rocket propellants, the excellent book “Ignition! An Informal History of Liquid Rocket Propellants” by John D. Clark is available on line: https://library.sciencemadness.org/library/books/ignition.pdf
F-16s contain hydrazine? :eek:
I volunteer for a week every year at RAF Fairford for the Royal International Air Tattoo - I’m on the refuelling team so I get hands on with all sorts of military aircraft, but loads and loads of F-16s. Not once have we ever been informed of the potential presence of hydrazine.
Can I safely assume that your leaky one was armed with missiles and it’s those that contain hydrazine?
I seem to recall some speculation at launch that one of the tasks for this craft was to refuel existing surveillance satellites. Is that likely? Or just more ill informed internet speculation?
- Good on you for your volunteer work.
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“Tattoo?”
- Thank you, but I really enjoy it. It hardly seems like work. I’m actually doing a second air show this year too at RAF Scampton.
- I know, it’s a strange use of the word: Military Tattoo
The X-37B cannot possibly refuel existing surveillance satellites. The KH-11/12 optical spy satellites are somewhat larger and heavier than the Hubble Space Telescope. They are about 4.5 meters in diameter, 15 meters long, and weigh about 18 tons (36,000 pounds, or 16,300 kg). About 14,000 pounds of this is maneuvering propellant: Improved Crystal
The entire X-37B only weighs 11,000 pounds. It’s payload capability is believed to be about 500-600 pounds. It would take 23 missions to refuel a single KH-11/12 satellite.
This illustrates the extreme cost of reusability. The X-37B was launched on an Atlas V 501, which normally has a LEO payload capability of 8,123 kg (17,908 pounds). Since most of this was spent just lifting the X-37B which has an approx. 600 pound payload, 96% of the launcher’s payload capability was squandered.
It’s not that reusable vehicles have no value or possible mission, but there is a very high payload cost to using them. They must provide something truly compelling in return to justify this. What the X-37B provides for that cost, nobody outside the program really knows.
Someone has to point up and say, “Ze plane! Ze plane!”
D&R
It wasn’t in the correct orbit for doing this, and surveillance satellites are not designed to permit in-space refueling, and in fact the propellant tanks are sealed up before they are even shipped for integration specifically to prevent any kind of leaks.
Yes, reusability comes with high cost, particularly for a winged vehicle where the weight of the wing structure and complex thermal protection systems are dead weight until the reentry phase. For what the Space Transportation System (STS “Shuttle”) cost per launch near end of life you could launch a Saturn V with more than five times the payload mass capacity. A direct comparison of the costs is difficult given the differences in mission requirements and capability, but the Saturn V vehicle was about US$110M in FY2010 dollars, and without having to integrate the Lunar Module the nearly US$1B in integration costs would be reduced significantly; with production economies of scale the Saturn V to LEO with a crew capsule and cargo it is feasible that the Saturn V could have been launched for somewhere in the neighborhood of $300M to $400M which is less than the average per-launch costs (including amortization of the reusable Orbiter Vehicle and maintenance and refurbishment costs for the system) of $450M. The one capability that the STS offered was to be able to recover space experiment platforms and retrieve and return a satellite for servicing and redeployment provided it was within the orbital range of the OV. This capability was used three times (STS-51-A, STS-32, STS-57) and never became a routine part of missions. Because it was a crewed spacecraft, there were also some significant safety restrictions on payloads which limited utility in comparison to an uncrewed heavy lift vehicle.
The X-37B is clearly a very different type of vehicle, designed to be an uncrewed orbital maneuvering platform and a testbed for future space capability as well as developing space operational procedures, and not hampered by the costs and restrictions associated with crewed vehicles, so even though it is not an effective large payload carrier it may be cost effective for certain purposes. Whether it also has an active role in space operations is not publically known, but again there are numerous mission requirements it could fulfill for which reusability could be beneficial or even imparitive. Unlike the STS, this is not a program for national prestige, and so certainly someone in AFSC thinks it is worthwhile despite the costs of reusability, and in terms of long term autonomous space operations it is certainly paving the way much better than the International Space Station is or the Space Launch System (delayed yet again) will do.
Stranger