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Robotic Space Plane Launches In Mystery Mission This Week
mpicpp writes: The United States Air Force's robotic X-37B space plane will carry a NASA experiment into orbit when it launches on its next mystery mission Wednesday. The liftoff will begin the reusable space plane's fourth mission, which is known as OTV-4 (short for Orbital Test Vehicle-4). Since it's classified it's not entirely clear what the space plane will be doing once it leaves Earth Wednesday. This has led to some speculation that the vehicle might be a weapon, but officials have repeatedly refuted that notion, saying X-37B flights simply test a variety of new technologies. The X-37B looks like a miniature version of NASA's now-retired space shuttle. The robotic, solar-powered space plane is about 29 feet long by 9.5 feet tall (8.8 by 2.9 meters), with a wingspan of 15 feet (4.6 meters) and a payload bay the size of a pickup-truck bed. Like the space shuttle, the X-37B launches vertically and lands horizontally, on a runway.
The Air Force has weaponized systemd and is launching satellites that can download it onto enemy computers at a moments' notice.
I hate to feed the trolls, but:
1) This is US Military, not NASA
2) The NASA budget is $18.4 billion or about 0.5% of budget
3) Dividing $18B amongst the population of 319M will give everyone $56. Not a good basic income.
4) NASA does some really great stuff that benefits every american citizen immensely. Like your 10 day weather forecasts? LIke your GPS navigation. Thank NASA.
5) There is nothing wrong with a good test platform. Where else are you going to get long endurance recoverable space data for classified purposes? Not the international space station to be sure.
Space weapons aren't illegal. You just can't have orbital weapon platforms for weapons of mass destruction (think nukes).
It's perfectly legal for any country to send up a satellite that could attack other satellites or space stations. It's even fine to put one up there that uses conventional warheads or kinetic weapons against targets on earth.
It's also perfectly legal to put up weapon platforms that are capable of launching nukes from space - it's just not legal to arm them with actual warheads.
The reason we don't do much of any of that is because a) we have no reason to attack anyone in space (yet), b) we can shoot down satellites from earth just fine, and c) we can attack other places on earth more efficiently and with less cost without orbital platforms.
Those who can't do, teach. Those who can't teach either, do tech support.
4) NASA does some really great stuff that benefits every american citizen immensely. Like your 10 day weather forecasts? LIke your GPS navigation. Thank NASA.
NASA does do some really great stuff that benefits every american citizen immensely, but your examples are horrible.
Weather forecasts are handled by National Oceanic and Atmospheric Administration (NOAA - I love that acronym for a weather agency!), who operate their own birds (though a few were launched by NASA).
GPS is built, launched, and operated by the U.S. Air Force. NASA has literally nothing to do with GPS.
Maybe because NASA is a political football that isn't allowed to do really cutting edge stuff without subcontracting the work to 48 out of 50 states to secure funding from Congress, while secret military programs can do science with less bother. Some of the Area 51 programs involved in developing OXCART ended up ahead of schedule and under budget because keeping stuff confidential sheltered it from the usual MIC/appropriations morasd. Likewise SpaceX is now on the cutting edge of rocket recoverability because it's more capable of taking risks and less hamstrung by accounting oversight. Maybe covert projects like the X37b are simply easier organizationally and thus easier avenues to doing unconventional science like testing ion engines than is the civilian space program. Remember, Hubble became possible because of Keyhole, which worked out the materials science and engineering aspects in secret.
There is some speculation that the AR2-3 may not be the engine used in current flights (see other replies to you post).
However, the AR2-3 is human rated. The X-37 is nominally unmanned, but hey the missions are classified, and because Halo Orbital Drop Shock Troopers. Of course some of the alternative engines you mentioned have been used on stages of previous manned flights and are thus presumably man-rated as well.
I did some Binging on the AR2-3 and found a NASA/Rocketdyne/OSC presentation that looks to be drafted around 2000.
Here that seem to make the case high test peroxide (HTP) technologies are the way of the future for upper stage propulsion:
Hydrogen peroxide was selected over liquid oxygen because it is dense, storable, capable of tolerating months in orbit, and meets safety restrictions for being part of the payload in the Space Shuttle.
Of course the Shuttle aspect is no longer a factor, but the other factors still seem to be in play.
Further into the paper, the USFE 10k peroxide motor is mentioned as a project to develop new HTP technologies. These technologies would be used for future HTP-based upper stages. They even have a goal of over 100 uses of an engine before it has to be removed for overhaul. Is that a lot in the world of rockets? As this paper was drafted around 2000 I would guess that the X-37 is using something a bit different that the bog-standard AR2-3 or has moved away from HTP technologies altogether.
Now to say that rocket science has moved away from HTP is not quite true. I don't think there are any big HTP engines used in lower stages. However, the Bloodhound SSC is using a HTP hybrid motor they are designing.
There is also research in to using HTP as a monopropellant for thrusters using a catalytic bed. I suppose the advantage here is that you have HTP as your oxidizer for an upper stage and then it can be used for maneuvering once on orbit. Similar, as you mentioned, to UDMH.
Take a look at the Introduction from the ESA paper referenced above. They cite several reasons why HTP is desirable and advantageous. Cost and safety being paramount. They also mention that Soyuz has been using HTP in its maneuvering systems for over 40 years. I think that HTP safety concerns have been effectively mitigated from the "explode because you looked at it funny" era.
As for performance it seems that HTP is as good as some other technologies, but it's no dog either and it seems to be a good fit for the X-37 or other small stages. Quote from the ESA paper:
The propulsive performance of hydrogen peroxide monopropellant rockets is about 20% lower than hydrazine, but the volume specific impulse achievable with 90% H2O2 is higher than most other propellants due to its high density. This is particularly useful for systems with significant aerodynamic drag losses and/or stringent volume constraints. With respect to bi-propellant and hybrid rocket engines, hydrogen peroxide yields a specific impulse comparable to other liquid oxidizers like dinitrogen tetroxide, nitric acid and even liquid oxygen..
It seems that HTP has many uses and rocket science has not moved away from HTP, indeed, it is being actively researched. It may or may not be used on the X-37 right now. It may or may be used on the X-37 in the future. With further attention to cost, safety, and, increasingly, environmental impact, HTP seems to be coming for you...
Weather forecasts are handled by National Oceanic and Atmospheric Administration (NOAA - I love that acronym for a weather agency!), who operate their own birds (though a few were launched by NASA).
NASA provides the design, launch, and project management for the NOAA satellites up until they are in orbit at which point the operations is turned over to NOAA. The last system they tried to launch with a reduced role for NASA was NPOESS--which was a complete failure. (Not all of which was NOAA's fault, it was a horrible idea that tried to merge NOAA & DOD requirements, but the reality is that there was no more appetite for NOAA to try to take on tasks that were being handled well by NASA and the successor project, JPSS, returned to the historic model of NASA program management driven by NOAA requirements.)