This is the X-37B. There's a contract for an X-37C, 1.8x as big and possibly capable of carrying humans.[1] That would be a nice little spacecraft. It's time to get past capsules, without building something as big and fragile as the Space Shuttle. The USAF and Boeing aren't saying much about it, though.
Capsules aren't inferior. In fact they can land on planets and moons without atmospheres, unlike space planes. And once propulsive landing of capsules is implemented, they can land on Earth without a landing strip, and even on boats.
There are a few things that wings can do that capsules cannot. Shuttle's wing were never actually used for their intended purpose. Wings allow for "once over and return" flights. Shuttle's creators envisioned it launching into a polar orbit, overflying the USSR to [redacted] then land back home without a second orbit. That requires the ability to 'fly' through the atmosphere to make up for the earth's rotation during your orbit. For a vehicle doing multiple orbits, such wings would allow it greater latitude on return. It wouldn't have to wait for its orbit to line up as perfectly with the intended landing site.
"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
The driving requirement of the Shuttle was that it should be feasible to steal a Soviet satellite sporting unknown new orbital technology, before the Soviets had the opportunity to intervene, and that it be prepared to fly fairly quickly whatever its faults to be ready for potential Soviet expansions into spaceflight as an area of competition.
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.
That's completely wrong. There was no serious consideration of stealing Soviet satellites. Everyone knew that we'd never be able to get away with that.
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.
You don't need something a tenth the size of the Shuttle to be an effective manned camera platform, even an effective manned camera platform with extreme cross-range.
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]
Yes a manned camera platform could have been much smaller than the shuttle. And the USAF had been designing just such a vehicle until they were forced to consolidate their program with NASA's Shuttle in order to "save money". So we ended up with a compromised vehicle that was too expensive and couldn't do anything very well.
If the Russian satellite is a secret, and the Americans steal it secretly, then of course they would get away with it. It's like a thief stealing from another thief.
Nobody seriously though Shuttle could bring back a hostile spacecraft. The logistics of such a thing are ridiculous. What Shuttle could have done was to bring back friendly sats. The only friendly sats worth bringing back would be something that couldn't be allowed to re-enter. The only things that couldn't ever be allowed to re-enter would be something nuclear, either a reactor or a bomb. Shuttle was envisioned as a system for maintaining some sort of nuclear tech in orbit. That never happened, but the worry that it would was a driving force behind Buran.
Such a system could orbit a number of times during maintenance operations of friendly satellites; It would not need the cross-range that the Shuttle was built for.
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.
Dragon is barely capable of landing on the moon if you remove the heat shield and replace it with more fuel and fit additional fuel storage in the capsule. Its powered descents on Mars would only be possible because of atmospheric drag.
That's cool, I didn't know that. So Dragon 2 is a Soyuz-like passive capsule when landing in atmosphere and a powered spaceship like the Apollo LEM when landing in vacuum. Very cool that they could cram those roles into one vehicle. Looking forward to seeing it work.
It could land directly, yes, but it makes use of the aerobrake for slow-down. Without that aerobrake it would not have enough fuel to do a powered landing all the way down and then return to orbit (I think -- I don't actually work for SpaceX; I'm just a fan). But it is my understanding that it has enough fuel to do a full propulsive landing from orbit and back again, without an aerobrake.
>But it is my understanding that it has enough fuel to do a full propulsive landing from orbit and back again, without an aerobrake.
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.
Are you looking at the CRS dragon specs? It is absolutely the case that future designs of Dragon are able to do a direct powered ascent from Mars. That requires a lot more that 450m/s. Current dragon can't do that, but I wasn't talking about current dragon.
Wikipedia seems to imply that the plan for Red Dragon is a direct atmospheric entry. It makes sense, they don't have a second stage that would last long enough to get there. They don't have the delta-V to get the second stage into a mars transfer with a huge amount of fuel and I doubt there's much utility in spending the 2.3km/s (or thereabouts) of delta-v in getting from the Mars transfer to a low Mars orbit when you can just use aerobraking instead. In fact, it would be highly abnormal for a probe to visit Mars orbit before landing.
SpaceX Dragon capsule can't land without atmosphere either it needs it to aerobreak it doesn't carry nearly enough fuel to come to a rest from orbital reentry speeds using propulsion alone.
> 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.
I don't understand how they can conclude that "the Dragon-2 has enough power and fuel to land and ascend back to lunar orbit" based only on a comparison of maximum thrust and a statement that the Dragon has an automated landing system.
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.
It definitely was not designed to de-orbit and land on the moon. It has nowhere near enough dV to do that.
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.
Lunar orbit isn't earth reentry tho, even the SuperDraco doesn't seem to carry enough fuel nor have the specific impulse for an earth landing when you remove the aerobreaking.
OK? I'm not sure what point you're trying to make, then, as there's not a no-atmosphere, Earth-sized body in the solar system for your argument to apply to.
Way I see it is, if we can land a rover the size of a minivan on a different planet, we should be able to do this without much more effort. Money, perhaps, yes; but, we've already done it.
You might think so, but the difficulty doesn't scale linearly with size and weight. For example there's a practical upper bound on airbags to absorb landing shock; we can't just build larger ones for a capsule carrying humans.
These things would fit inside the shuttle which creates a very different design with much lower thermal stresses.
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.
Yea, wings on spacecraft are about as elegant as parachutes. They can make sense for certain uses, but, as a rule of thumb, they are inelegant and not futuristic.
Capsules are lifting bodies too. Apollo had a L/D of 0.368 and "steered" by rotating. Dragon uses the same technique (albeit with a slightly lower L/D), and Dragon 2 will have a tungsten ballast sled so it can change its angle of attack dynamically during re-entry.
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]
There isn't really a sharp distinction, is there? The primary method of generating lift for both wings and lifting bodies is simply the fact that it's an inclined plane moving through a fluid with positive angle of attack.
They each have some length of wing, but get a lot of lift from the shape of the fuselage. These craft wouldn't exist without lifting body research.
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.
> Not using fuel while landing saves precious cargo capacity
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.
Following this principle I sometimes think the new east span of the Bay Bridge is/was a $6 billion boondoggle. The historical (and I thought, beautiful) original span was not retrofitted because Caltrans said they could build a new span for less that would have a longer lifespan. The simple, cost effective viaduct design was rejected as not grand enough for a Bay Area bridge and a short decorative, self-anchored suspension bridge was added to the viaduct for an extra $5 billion. It would sure have been nice if that money had been spent on a couple of additional bridges across the bay. One from the 101/380 to the 880 near the Oakland airport would sure help the traffic problems some. With interest rates near zero, I'm sure the finances for a toll bridge would work out. Just need the political will.
Yea, I'll withdraw "inelegant" from my original comment, since I was mostly intending to dispute (concurring with colordrops) the suggestion by Animats that wings are more advanced than capsules. ("It's time to get past capsules".) I wouldn't say the shuttle was a pillar of elegance, but I'm happy to agree that wings can be elegant on the right spacecraft (although, as I alluded to, the intuition that they are less wasteful than consuming fuel can be a bit misleading).
I'm not sure describing the space shuttle as 'fragile' really does it justice. The ceramic tile system was fragile, but the requirement for the tiles came from the required re-entry mass, which included carrying down a full payload bay as well as the astronauts. That was imposed on the system as a military requirement (the rumor is that the Military wanted to be able to potentially snag a satellite and return it to earth). The X-37B has significantly less mass coming down, so much less energy to dissipate, and so less heat generated. Enough less that a spray on thermal coating over titanium is sufficient (at least according to the Air & Space article I read on it).
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.
The space shuttle Columbia was destroyed with all hands after it was hit by some insulating foam from its own external propellant tank [1]. The noise from its launch was also a serious threat [2]. I think it is fair to call it fragile. Of course, all space launch vehicles are fragile, but for a manned vehicle the shuttle sure had tight tolerances for safe operation.
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.
SNC are building a small shuttle-like thing that lands gently on a runway. they planned to build a crewed version, but lost the NASA competition to SpaceX and Boeing. They won a contract for cargo, with an unmanned variant, possibly because NASA is really interested in "dissimilar redundancy".
I always imagine it creeping up on unsuspecting satellites like some kind of space puma. All up close and personal like, giving them a sniff and then slipping away undetected.
Wasn't there a story somewhere awhile back that the Russians had launched satelites and yet strange movement of the supposedly jettisoned pieces was detected?
If the satellite has "local" sensing equipment, then sure there's nowhere to hide. How many satellites have that? If such sensors aren't installed, it's not like anyone down here on the ground will notice. If someone did notice, what could they do in response? Complain to the media?
If you wanted to rendezvous with a foreign spy satellite (I have no idea why you would) you couldn't do it in a huge space plane because diplomacy. You'd have to send a tiny non-trackable interceptor thing. If you needed a vehicle to deploy such things from, then perhaps the X-37 would make sense.
Amateurs have been tracking it [0] and even photographing it [1] while in orbit. Any government that has the capability to send satellites to space can do the same.
Actually, most objects of any size are actively tracked pretty much continually from the ground. That's especially true of a state's classified space plane.
My guess was to refuel spy satellites. I imagine those sats are tough and can survive a long time. But when they get low on gas they can only do station keeping. If you can count of fuel coming, there's a lot more freedom to shift the track a half a degree as needed.
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.
> On-orbit satellite servicing and refueling has not been performed as of yet
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.
While it's not entirely impossible that some classified mission has done some basic reservicing of a DoD bird, I know from working on Restore-L that we will be the first ever to do what we are doing, namely autonomous rendezvous and capture of another satellite in LEO and reservicing.
The X37 does not have the mechanical tools or sensors required to perform the kind of reservicing Restore-L is doing.
Well, Restore-L looks to service satellites not designed for service. If you knew the X-37 was coming, and you knew it was a flying gas station, i'd bet that problem is far far easier. You don't have to take the target apart in space and put it back together. On the other hand, an easily accessible common connector seems like something we could have standardized on and implemented 15-20 years ago.
Again, i have no evidence of any of this. But it's my favorite pet theory.
Hubble fixes?
Also it seems that quite a few shuttle missions were satellite servicing missions including relaunching sattlites that failed to get into the correct orbit: https://en.m.wikipedia.org/wiki/STS-49
Turns out we are funded. PACE may be funded as well actually, but there's no clear indication either way. I was at the all-hands a few weeks ago where it seemed to be a bit more grim but lately there has been some talk of PACE surviving.
Refuelling sats won't ever be a thing. There is no real need. Any refuelling vehicle will need it's own propulsion/rcs system and a docking scheme. Once docked and/or latched onto the target ... job done. The refuelling vessel becomes the new orbital manoeuvring system for the depleted sat. Cost wise, that makes more sense than having a large tanker bouncing around between clients. With the switch to ion propulsion total fuel may also not be the limiting factor. Ion thrusters can become very inefficient and/or useless after years in space. Flying up and bolting on a new rig is simpler than trying to actually service/replace such parts.
Refueling satellites will absolutely be a thing :) Restore-L is going to do just that in 2020-2021, and do it autonomously to boot.
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.
i don't think it's refueling anything. for one it has a pretty small payload, but more importantly it has a low orbit (~320km). there's some decent speculation here:
Eh, you're probably right. Those spy satellites have a very elliptical orbit. Probably only a few seconds when they could be close.
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.
Surprised nobody's mentioned this possibility as it usually comes up re: the X-37B. Terrifying but I think not out of the question given the strategic potential of such a weapon.
> During the Vietnam War, there was limited use of the Lazy Dog bomb, a steel projectile shaped like a conventional bomb but only about 1" long and 3/8" diameter. A piece of sheet metal was folded to make the fins and welded to the rear of the projectile. These were dumped from aircraft onto enemy troops and had the same effect as a machine gun fired vertically.[3][4] Observers visiting a battlefield after an attack said it looked like the ground had been 'tenderized' using a gigantic fork. Bodies had been penetrated longitudinally from shoulder to lower abdomen
Adding to this: all war is utterly terrifying. People like to pretend it's not but it is. It's not "only" soldiers being killed in all crazy ways but other people being killed, raped, tortured, etc. Babies included like when the Japanese would throw them in the air and let them fall on their katanas. That's reason enough to avoid war.
Orbital kinetic bombardment is a silly concept suitable only for cheap sci-fi novels. There's no benefit in having kinetic weapons permanently positioned in orbit. The satellites would be easily tracked and vulnerable to ASAT weapons. They can't strike a target much faster than a ballistic missile launched from land or sea. And they would be much more expensive. Anything in orbit is out of reach of maintenance. It takes a lot of energy to get a satellite into a stable orbit, and then yet more energy to de-orbit a missile.
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.
No that's all wrong. Firing a missile from orbit has less surprise value than firing from a submarine because satellites can't hide. There's no difference in kinetic effects; a non-nuclear ballistic missile can hit just as hard at a lower cost (do the math). A kinetic projectile launched from a satellite is no harder to intercept than a ballistic missile in the terminal phase, and satellites themselves are highly vulnerable. A big chunk of mass landing near a target won't have much effect. And the projectiles couldn't be just rods. Due to the variability in rockets used for de-orbit burns as well as atmospheric conditions they would need fragile and sensitive guidance packages.
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.
> They don't follow a trajectory. They might just travel straight down from a geostationary orbit
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 am wondering, what kind of impact would the wind have on these projectiles? Or even on ballistic missiles?
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).
Wind and other transient atmospheric conditions have a major effect. That's why individual unguided projectiles can't reliably hit a target more than about 4 miles away, and even at that range you have to be really lucky. The range from LEO to surface is a lot longer.
If you were going to use this as a first or second strike kinetic weapon platform (and prepared to tap dance around the "no militarization of space" treaties by claiming it's an aircraft), then your biggest asset is orbital velocity. It's sitting up there doing 7-8 km/s.
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?"
Orbital velocity is no asset. In fact rather the opposite. You can't just start aerobraking. There isn't enough air in orbit for parachutes or wings to have any noticable effect. The only practical way to get out of orbit using current technology is to conduct a de-orbit burn with chemical rockets.
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.
You absolutely can just start aerobraking if you have maneuverability on the launch vehicle (because it's small, packed with fuel, and limited duration).
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.
This is 100% wrong. You don't understand orbital mechanics. Everything follows a trajectory until force is applied. When you release something in orbit it doesn't fall down. It continues orbiting until an attached rocket motor does a de-orbit burn. Rocket motors are subject to manufacturing variations plus there are a lot of atmospheric effects on the way down to the surface so any missile would require a sophisticated guidance system to have any chance of striking a target.
Prove to me that a rocket simply MUST be burnt, to set an orbiting mass in motion.
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.
You are still 100% wrong. Magnetic induction wouldn't be be practical because it would disrupt the satellite's orbit. Inert gasses are too heavy to be practical for the amount of delta V needed. You're just making things up and missing basic physics concepts.
You're imposing constraints where there are none, and declaring physical law as an insurmountable barrier, because you are sourcing all materials involved as terrestrial in origin, and insisting on reusability.
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.
Assuming everyone lives, builds stuff, and maintains stuff at the bottom of the gravity well is an assumption well suited to the present day, but not to the setting of most cheap sci-fi novels.
The main problem is that even 500kg at sub-7 km/s doesn't deliver that much energy. Conventional weapon of the same mass is way more effective (and this is why ICBMs now can deliver conventional warheads).
If the X37 is public they probably have something bigger and better tucked away in a hanger somewhere remote. Think about how long the F-117, SR-71, U-2, B-2, or RQ-170 were kept secret. There is no way they haven't thought about how to use this in a military capacity.
People always talk about kinetic strikes in the context of big flashy things like rockets and spaceplanes. 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.
This reminds me of a novel weapon from the Daemon novels. Basically, small semi-guided darts dropped from weather balloons that were used as antipersonnel weapons rather than as a replacement for conventional explosives.
Intercepting stratospheric balloons is child's play, possibly literally, compared to intercepting chunks of metal flying at 10km/s, which are the alternatives under discussion.
> 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.
The Soviet Union spent 40+ years, and many pilots' lives, trying to devise a means of destroying CIA balloons operating at 30km altitude. SAMs, AAMs, artillery and even ramming all mostly failed.
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.
cool idea but I'm gonna assume its a lot more expensive to send up an X-37 and have it crash back down then it is too just send a few nukes at your target.
If you look at it purely from a costs perspective, maybe.
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.
Preface: I don't think this is a likely explanation.
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).
Toxic propellants. Nitrogen tetroxide / hydrazine. Both components are highly toxic.
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.
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 combustion byproducts are toxic and some uncombusted propellants are left in the pipes and can leak out. Has to be washed.
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
You hope it's all combusted perfectly, but there's no reason to take the risk based on a hope. And the combustion byproducts aren't that much less toxic than the fuel. Also not all of the fuel will be used, so there's some in the tanks. That needs to be removed, and could leak if there was any damage.
If you read the jobs page at SRI, there's a bunch of stuff about modeling microwave communications/in the atmosphere/for offensive cyber. I wouldn't be surprised if this guy were involved in that sort of mission.
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.
Risk reduction is a completely normal term in R&D. It just means experiment to raise confidence in a particular proposed approach, before going full scale production. It is meant to raise the TRL[1] of a technology, to gain experience with it.
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.
Just to add some details to the above well-informed comment:
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...)
I work for a gov contractor. "Risk Reduction Tests" are a common thing. What they mean is a test done partway through a program, to validate that the base assumptions for the program are correct and there haven't been any glaring oversights in terms of the feasibility of the project.
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.
My assumption is that "perform risk reduction" means "try things out to make sure they will work when we use them later". For instance, now they have more confidence that they can leave the spaceship orbiting for two years without something breaking. Kind of like Apollo 8 (fly around the moon without landing) was risk reduction for Apollo 11 (land on the moon).
Risk reduction can be thought of finding a cheaper / faster / easier way to test a hypothesis than performing a full experiment. Think of it like surveying a sample instead of a population.
Risk reduction - pretty well explained above.
Experimentation - Standard definition. Trying out stuff.
Concept-of-operations development - take the experiments and turn them into instructions and procedures for normal operations. Think of it as production compared to experimentation being dev. (concept of operations is a standard document describing the 'how' of something, typically in a tech-agnostic way)
Basically they are using this vehicle to figure out how to do this stuff with future vehicles in a scaled-up way.
> How, pray tell, does anything "perform risk reduction"? Does that phrase have any meaning in English, or any other terrestrial language?
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.
So why are they publishing this super secret mission with photo containing people wearing hazmat suit? This doesn't look like a leak, it's full blown press release!
It's a form of propaganda. Release just enough information to pip curiosity and speculation. Then call the rest of it classified. For all you know it could be having a dummy payload but call it classified and the bad guys would think that it has some advanced technology.
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.
[1] http://www.spacesafetymagazine.com/aerospace-engineering/spa...