Unmanned U.S. Air Force space plane lands after secret, two-year mission
reuters.com
reuters.com
[1] http://www.spacesafetymagazine.com/aerospace-engineering/spa...
Even simple cylinders can be lifting bodies. Shuttle and Falcon 9 both have a L/D of 1.[1] On Falcon 9 the first stage acts as a lifting body, using the grid fins to "trim" the big cylindrical body making it act like a wing.
In the SpaceX landing videos you can see the stage pitch up on reentry. This is no accident. Upward lift = more atmosphere traveled through = more drag = less landing fuel needed = more payload to orbit. A nice optimization by the SpaceX team!
>you don't actually need wings by the way, it's kind of a common misconception around, you just need some lift over drag number, or lift vector - and steer back to the launch pad --- Elon Musk[2]
[1] https://spaceflightnow.com/2017/04/04/musk-previews-busy-yea...
[2] http://shitelonsays.com/transcript/npc-luncheon-with-elon-mu...
This space plane and the shuttle shouldn't be derided for gliding into landing. Not using fuel while landing saves precious cargo capacity. If the main argument against them is that they can't land on the moon, I don't understand why a future craft couldn't both glide into an atmosphere and use thrusters in a vacuum in to land.
Those wings are also a lot of mass, and hence take away from payload. In fact, propulsive landing always takes less mass than wings in the limit of large craft size. (You can see this by taking an equivalent limit, the limit of thin atmosphere; for sufficiently thin atmosphere, the amount of surface area you need to brake diverges but the amount of fuel to stop propulsively is fixed.) In this sense, propulsive landings naturally succeed wings as crafts get larger.
Elegance in engineering is fulfilling the requirements in the simplest, cheapest way possible.
Thanks for your comments.
People pay for a similar experience! ;)
You need a big rocket to slow down and land. At which point it's a very different machine.
> The Dragon-2 has enough power and fuel to land and ascend back to lunar orbit. The Dragon's SuperDraco has higher performance than the Apollo Lunar Module. Apollo LM descent engines has 10,000 lbf thrust, and 3,500 lbf thrust for ascent (the lander part is left behind). The Dragon's SuperDraco has 16,000 lbf thrust. The Dragon also uses computers to control throttle and land (much more fuel efficient). Hence, the Dragon-2 has enough power and fuel to land and ascend back to lunar orbit even if it carries all it's parts during ascent. However, it may need to cut crew from 7 to 3 to loose more weight for fuel.
(Plus, I said "more SpaceX" as in "capsules with powered descent", not "SpaceX's exact current models as already implemented"...)
Estimates are that the Dragon v2 has about 400m/s dV. This is around what it would need for controlled landing or abort. It takes around 1720m/s just to get to the stationary Lunar surface from Lunar orbit; If a Falcon upper stage detaches during the leg of the mission between Earth and Luna, the necessary delta V for the rest of the mission will be around 5080m/s. This is a lot. You would have to build another fairly large vehicle to accomplish this mission - Dragon v2 would be an afterthought.
At the very least, they'd need to consider the dry weight and fuel load to make a fair comparison - maybe they did so offscreen but it's not mentioned anywhere in the post.
Maybe it has been designed to work as a technology platform for deriving a lunar lander. But the Dragon 2 design is just not capable of doing it, not even close.
Work in progress..Well along in progress.
And especially interested on what the options for the problem scenarios look like (e.g. burning off too much or not enough velocity).
Not even close. Dragon has something like 450m/s of dv to use. Getting from the surface of Mars to orbit takes 3800. Orbital capture requires around 2000m/s. Without aerobraking, it couldn't enter Mars orbit, let alone land.
Remember, the initial shuttle design was actually viewed as an improvement by real rockets scientists even if the project ballooned into ridiculous territory there really is a lot of value in those short stubby wings.
"The militarily specified 1,085 nmi (2,009 km; 1,249 mi) cross range requirement was one of the primary reasons for the Shuttle's large wings, compared to modern commercial designs with very minimal control surfaces and glide capability." https://en.wikipedia.org/wiki/Space_Shuttle
There were a lot of other requirements and stakeholders that were part of the planning process, and any of them who didn't understand that espionage was a critical component were left wondering why anyone would design such an expensive, impractical failure; Why every stage of the process where it seemed to be unworkable, someone said "Yeah, don't worry about that" and poured money on the problem. Aside from direct requirements, we also encouraged the Soviet Union to spend lavishly copying our design.
By the time the USSR unexpectedly broke up, Energia had just (unsuccessfully) flown a test run with a giant Polyus laser weapon. Mission accomplished, right? But we didn't then want all of the Soviet scientists to spread to the winds and start building ICBMs for anyone who could pay. We needed them to stay in Russia until Russia could become a solvent, stable state.
So we said "What sort of international cooperative effort could we use a whole bunch of Shuttle AND Soyuz flights for?" and designed (or adapted) a space station around that requirement. We decided to revamp Reagan's ill-fated "Space Station Freedom" program into the ISS.
That's the only reason we didn't retire the Space Shuttle long before the Columbia.
I get a lot of "Nobody seriously thought this", but the high cross-range required of single-orbit-and-land is the long pole in the tent that stretches the rest of the requirements; It's not a reasonable tradeoff unless espionage was a use-case that could not be ruled out.
Without the requirement to land a large cargo bay with an extreme cross-range, the optimal design looks nothing like the Shuttle. The Shuttle cost an order of magnitude more than that optimal design.
The driving requirement was to act as a successor to the SR-71. Launch, make a single reconnaissance pass over the Soviet Union, and then utilize the cross-range capability to land immediately so that the film could be developed. But by the time the Shuttle was actually built, spy satellites equipped with digital cameras had improved so much that it became moot.
We had effective unmanned film camera platforms in space long before we had CCDs, long before the Shuttle was contemplated.
> During the 1950s, a Soviet hoax had led to American fears of a bomber gap. In 1968, after gaining satellite photography, the United States' intelligence agencies were able to state with certainty that "No new ICBM complexes have been established in the USSR during the past year."[10] President Lyndon B. Johnson told a gathering in 1967:
>> I wouldn't want to be quoted on this ... We've spent $35 or $40 billion on the space program. And if nothing else had come out of it except the knowledge that we gained from space photography, it would be worth ten times what the whole program has cost. Because tonight we know how many missiles the enemy has and, it turned out, our guesses were way off. We were doing things we didn't need to do. We were building things we didn't need to build. We were harboring fears we didn't need to harbor.[10]
I thought the link to the x-37c was interesting but I can't find anything that suggests it is anything more than a proposal at this point.
Edit: I would argue that the huge mass of the (STS) oribiter was pretty much its greatest problem, and could be largely attributed to the requirement that the whole thing must be reusable. Not only was it problematic to bring all that mass down, but consider this: the system could bring almost as much mass to orbit as the Saturn V rocket [3], but almost all that capacity was consumed by the orbiter, leaving "just" 27,500 kg for payload. Of course, that is still a huge payload capacity, and the orbiter itself could, to an extent, be considered useful payload.
[1] https://en.wikipedia.org/wiki/Space_Shuttle_Columbia_disaste...
[2] https://www.nasa.gov/mission_pages/shuttle/launch/sound-supp...
[3] The maximum takeoff weight of a space shuttle orbiter was around 109,000 kg (https://en.wikipedia.org/wiki/Space_Shuttle_orbiter#Shuttle_...) while the maximum LEO payload of the Satrurn V was around 140,000 kg (https://en.wikipedia.org/wiki/Saturn_V).
Missions - that don't need people - are the luckiest missions in the world..
It may be all electronic surveillance. I guess, you can count on satellites not changing after they're launched, so the electronics package would be good for a couple years. come back, get a new package for new surveillance.
Just delivering fuel though, has a lot of value, and you could keep using the same platform for a long long time. Seems to fit better with many multi year missions.
I'm sure somebody knows. But, you know, not me.
Again, i have no evidence of any of this. But it's my favorite pet theory.
Declassified on-orbit satellite servicing and refueling has not been performed as of yet. I wouldn't be shocked if the X-37 has refueled a NRO bird or two (or just simulated it) as a test.
The X37 does not have the mechanical tools or sensors required to perform the kind of reservicing Restore-L is doing.
I work on Restore-L and believe me, there is a huge need for on-orbit satellite refueling and reservicing. The vast majority of satellites reach their end of life due to depletion of fuel, not due to electrical problems or sensor issues. This will be a huge business one day.
http://www.airspacemag.com/space/spaceplane-x-37-180957777/
tldr possibly a test bed for new smaller electronics packages designed for new smaller satellites
It sounds cool, and I can think of a few ways that could work, and it would be super useful. So I'm sticking with my personal conspiracy theory. But yeah, it's a low likelihood of being true.
Recent US spy satellites such as PAN (https://en.wikipedia.org/wiki/USA-207) have started using much, much more aggressive manoeuvring strategies in order to do line-of-site microwave dish spying and spying on commercial sats.
This is unusual for "geostationary" satellites, as it wastes precious fuel. If there is no restriction on the amount of fuel used, they can stay up a lot longer than a normal satellite could.
http://www.heavens-above.com/orbit.aspx?satid=40651&lat=0&ln...
If it was to get close to a non-US military satellite, one could expect people to complain diplomatically, at least.
[0] http://www.space.com/8470-secret-37b-space-plane-spotted-ama...
[1] https://www.universetoday.com/65338/amateur-astronomer-image...
Don't discount the PR disaster that would ensue from the US using nukes in any scenario other than retaliation for a nuclear attack. Nukes used in anger would likely mean worldwide condemnation, sanctions, and pissed allies complaining about fallout.
But if you think it is, there's a big advantage of kinetic weapons over ICBMs, namely that they are a lot more credible as a first strike weapon. ICBMs launches are quite detectable, allowing counter strikes (hi there nuclear deterrence).
Never underestimate passionate nerds and their ability to notice unusual things!
> I'd be a lot more worried about them being dropped from stratospheric balloons - maybe not so useful for full scale bunker busting but extremely cheap to make and almost indefensible against as a strategic strike system.
If you meant to speak from the point of view of a revolutionary (why?) and note that stratospheric balloons would be a cheaper way of killing revolutionaries than ICBMs or Rods from God, sure, I agree. There are a million ways to shoot fish in a barrel. Forgive me for assuming your point-of-view party was militarily capable.
Eventually by the late 1980s they developed the Myasishchev M-17 balloon interceptor aircraft, with a dorsal cannon-turret and able to loiter for hours at 22km. Still not quite sufficient.
Now increase the balloon altitude to 50km and they should be safe against any opposing force with early-2000s levels of military capability.
Something similar has already been used here since WW1.
1. Surprise. All land-based launch sites are actively monitored all the time, giving countries advance warning when a missile is launched. Submarine launches cut down this warning time, but still light up radar and thermal all over the place. A kinetic impactor falling from LEO can hit its target before the enemy even reports up the chain of command (we're talking single digit minutes).
2. Lack of radioactive fallout while still having larger destructive force than conventional munitions. If you need to destroy an entire air base far behind enemy lines, but don't want nearby population centers to be irradiated, you're looking at pretty bad options today, compared to a kinetic bombardment.
3. You can't really intercept a kinetic impactor. We have the technology right now to shoot small rockets right out of the sky, and at least a chance of intercepting ICBM payloads. With a kinetic rod, though, intercepting it wouldn't really do very much - it's just a big chunk of mass moving really fast. The best you could do is break it into smaller pieces that are still moving really fast.
https://en.wikipedia.org/wiki/Kinetic_bombardment
These are not things that get fired. You don't launch them.
They don't follow a trajectory. They might just travel straight down from a geostationary orbit, depending on implementation. Yes, a guidance package might be necessary (depending on target discrimination, and precision, which in warfare isn't always required). They aren't gliding like smart bombs though.
At the speed of re-entry, and with possibly just 100 short miles to close, a defensive interceptor would be unwarned, have to acquire possibly many targets (one need not drop only one). Intercepting vehicles would have to close on a target in an arc representing a distance longer than the hypotenuse of the right triangle between the kinetic slug, the interceptor's launch site, and the defended target.
The slug is simply released with no indication of ingress. From a geostationary orbit, it just starts getting closer very fast. Cover it with EM absorbant, non-reflective material, and there's even less hint of activity, until the re-entry burn at approximately 60 miles altitude. Unless the target itself is equipped with interceptors, and lots of them, it will be difficult to notice and recognize in time, and even harder to catch and defeat.
That's not how orbiting works. If you want your projectile to travel straight down, you need to cancel all it's orbital velocity. For geostationary orbit, that's 3km/s of delta V needed.
Obviously, you can de-orbit with less delta-V, but then guidance starts becoming necessary.
> The slug is simply released with no indication of ingress. From a geostationary orbit, it just starts getting closer very fast. Cover it with EM absorbant, non-reflective material, and there's even less hint of activity, until the re-entry burn at approximately 60 miles altitude.
There is going to be some kind of burn to start de-orbit, you could simply monitor for that.
I would imagine a nuke having such a large explosion that missing the target by a kilometre won't matter too much. But with a kinetic projectile that kind of deviation would not be acceptable (unless we are talking about seriously big projectiles, like in Tunguska etc).
Obviously you don't want to do a powered de-orbit for reasons mentioned (you burn fuel & lose kinetic energy). However, if you're flying low enough, couldn't you aerobrake your projectiles after release and have them de-orbit themselves?
For comparison, the X-41/51 scramjet programs appear to be aiming at the mach 5-9 region. So less than 1/2 as fast.
As complicated as the materials science and guidance has to be for any X-71-based projectiles, slowing down and terminal guidance (ablative coatings and sacrificial control surfaces) seem like easier problems than boosting up to ridiculous velocities.
As for tracking, you get the heat bloom as it aerobrakes, but if you manage to keep it coherent through re-entry then the ridiculous speed largely moots that.
At 5 km/s, with a prograde orbit, you're from Istanbul to Beijing about 24 minutes (by my sleepy calculations?). The exercise seems more of a question of "How steep can you dive (aka how much heat can you handle)?" than anything else.
PS: Well, and "How the hell do you communicate-with / sense-from a platform surrounded by air that hot?"
Of course that's all pointless because a ballistic missile launched from Earth could accomplish the same mission at a far lower cost with greater reliability and survivability.
Regardless of what orbit you start from, you dip into the atmosphere, deploy your payload from there, voila.
Now anything you dropped has to deal with a furnace of superheated air, and the question of whether it's possible to have control in those conditions, but it's definitely going to de-orbit.
And the atmosphere is going to supply most of the energy, rather than direct retro burns from the delivery vehicle.
So you're just going to target the equator then?
Propellant is a conventional means, but certainly not the sole means. Magnetic induction could eject a slug from an orbiting platform, or inert gases could jettison to induce motion. Burnt fuel isn't a requirement.
You insist on a rocket motor. But you just resist the idea of this form of orbital weaponry.
A large enough asteroid could enter into earth's gravity well and chart a straight line to impact.
You presume preconceived concept of a weapons platform already in orbit, controlled from the ground, or by a terrestrial entity. But a weapon of lunar origin might insert into the atmosphere differently. As with any weapon, an approach to target should be the least defensible path. After atmospheric re-entry, when position is given away, you'd want the penetrator to travel as perpendicularly to the target as possible, but prior to that moment, any stealthy approach is game.
I'm not 100% wrong. You're 100% obstinate.
Magnetic induction would also apply opposing forces to the launch satellite, but that doesn't matter if the launch satellite is just as disposable as the slugs that destroy the target.
Inert gases are too heavy, only if the weapons program tries to collect them on the ground and launch them into orbit.
I'm obviously making things up, because this is a system open to invention, given that it doesn't actually exist yet. This concept is less practical, if you operate within existing constraints, using only rocket propellant to boost objects into orbit, and then subsequently de-orbit them.
Game changers emerge, when new ways of operating in space appear. Even if this is "less practical" right now, after the introduction of adjacent technologies, as an existing concept it could suddenly become practical. For example, with the introduction of a space elevator, boosting such a weapons system into orbit is less costly. Then, more of its components become readily disposal at practical values.
I'm not required to operate within existing economic constraints, to consider ideas that are not actually limited by physical laws.
That is utterly terrifying.
Maybe my interpretation is spoiled by all those sci-fi disaster movies and games and they are just wearing protective suits in case of fire etc.
The big space shuttle used those for its maneuvering propulsion, and ground crews had to wear all the protective gear after landing until the propellant had been drained.
The emergency APU on F-16 fighters uses hydrazine and if it was used and the jet landed on a civilian airport (e.g. engine failure) then you need to have it safely washed before anyone can approach the plane. https://youtu.be/Puia_yQxir8?t=178
That brief exposure, before they got their oxygen masks on, put them in the hospital for a couple of weeks. It really could have been worse.
I believe the technical procedure for unprotected ground crew dealing with a leak of this stuff is, roughly, "turn around and run for your life." Hence the guys in funny-looking suits.
The orbiters "perform risk reduction, experimentation and concept-of-operations development for reusable space vehicle technologies," the Air Force has said without providing details. The cost of the program is also classified.
How, pray tell, does anything "perform risk reduction"? Does that phrase have any meaning in English, or any other terrestrial language?
"The cost of the program is also classified." - naturally! As someone much, much smarter than me noted, there's very few real state secrets, but there's tons of career-ending blunders, accounting mistakes, ridiculous overcharging and independent validation and verification companies that just happen to be owned by a distant relative. Those categories are not mutually exclusive.
In my software day job, we write throw away code to test out an idea, and we call it proof of concept. It is used to find out early if the schedule for a feature is too optimistic by demonstrating that the approach doesn't work.
1 - https://en.wikipedia.org/wiki/Technology_readiness_level
Sometimes people who are not used to management of large-scale projects are surprised by the development of tools and specialized vocabulary in project cost/schedule/risk assessment. The following is a pretty good summary of some common tools that integrate cost, schedule, and risk analysis: http://www.iceaaonline.com/ready/wp-content/uploads/2015/06/...
See in particular the first couple of slides on motivation, the "risk cube" on pages 19-20, the scatter plots of cost/schedule on pages ~30, and the example "risk lists" on page 57. Project management can be viewed as an assault on the remaining top items of the relevant risk list.
All these concepts are standard practice for large aerospace projects. There will be risk analysts with stats or operations research PhDs running simulations and developing tailored methods just to assess risk of large projects. (Example: https://viterbi.usc.edu/sae/faculty/part-time-lecturers/jair...)
This may not be what you meant, but suppose that my sister Alice is an alcoholic, and drinks during the day at her job (they're very tolerant). I am concerned that she will cause a traffic accident, so I encourage her to enroll at Alcoholics Anonymous, or I offer to pay her taxi fares or buy her a bus pass. Ta-da, risk reduced!
In this instance, I think they're either referring to the risk of crashing the plane or something conveniently censored by government classification.
Basically, when contractors (Boeing, in this case) win a job from a bid, they don't then just go off for the duration of the contract, and return to the government at the end of the contract and hand over a delivery. There are generally a series of incremental deliverables and tests during the contract to validate that the contractor is actually working on the contract. Risk reduction tests are one of the mid-program deliverables.
Basically they are using this vehicle to figure out how to do this stuff with future vehicles in a scaled-up way.
If the US has kinetic weapons in space, I very much doubt they would plan to use them against North Korea. NK is decades behind in military technology, and the US/SK forces would have air supremacy over NK in a matter of hours, with the capability to pummel anywhere in the country with conventional weapons with relative impunity.
If they have them, using them would almost certainly tip their hand to Russia / China etc, and lose them a significant strategic advantage in any future conflict. Trump and his cronies have been talking tough about China (Bannon literally said 'We're going to war in the South China Sea ... no doubt') and while it is a) doubtful that this will happen, given the recent warming of relations with China (mmmm... chocolate cake) and b) in the event it does happen, unlikely to escalate to the use of previously undisclosed super-weapons, it still makes sense to keep this hypothetical weapon secret from larger, more-powerful potential adversaries, just in case.
Also, if they're rearming with Kinetic Weapons it suggests they've already fired a few
> Power supply for electronic warfare sources?
Since you mention a power supply, I'm going to assume you don't mean dropping EMP bombs, which, even if they exist would be more easily dropped from high altitude aircraft, and would likely be less effective against such an outdated military.
I'm going to assume instead you mean some kind of cyber-weapon. The alleged cyberwarfare campaign against NK's ICBM programme most likely takes the form of malware (like stuxnet) introduced through conventional hacking methods or even on-site deployment. Sure, you can send someone a phishing email from space, but it's not any more effective than sending it from an office somewhere.
That was my point, yes. I'm not sure "fire" is the right word. You can just drop them.
> I'm going to assume instead you mean some kind of cyber-weapon
Cyber? What? If you know some operating frequencies of internal systems or control bands, you can use targeted energy instead of broad-spectrum EMP.
http://www.skyandtelescope.com/astronomy-news/observing-news...