This is certainly an interesting approach, but more interesting to me is the fact that ULA's new rocket (the first they are actually building) won't launch until 2019. As SpaceX have been launching their own since 2010.
Also interesting is the reasoning behind capturing parts of the rocket (and it is only parts) in midair. ULA say this is because the expensive bits are small, and essentially imply that they can get most of the 'wins' with not much effort when compared to SpaceX's "land it on a boat" approach. This may well be true but it seems SpaceX's approach is thinking in wider terms of the re-usability required for frequent space flight, rather than cheap space flight.
I have a keen interest in space flight and SpaceX in particular, so take my opinion with a pinch of salt, but this article reads to me like SpaceX are well over a decade ahead of the ULA, much more forward thinking, and overall the more exciting player in the commercial space-race.
You probably already know this, but just want to point out that SpaceX's approach goes way beyond "landing it on a boat". For today's launch (and launches in the near future), they'll land it on their barge. But after the landing system has been proven, they'll land it on the launchpad it took off from. Work is already underway at Kennedy Space Center to make a launch site capable to have a rocket landing.
I do wonder how much this will save SpaceX in logistics cost once it's in place. Seems a lot cheaper than coordinating a helicopter to catch a rocket engine in mid air, land it on a barge, and ship it back to shore.
Don't forget that SpaceX aims for that red rock out there. Reusability in this case may go much farther than saving on convoluted blocks of metal but also includes gathering data and experience for a surefire way to get there and back.
ULA doesn't have a whole lot of choice on this one... They need to stop using RD-180's from Russia, which means Atlas is going away. Delta is too expensive to pick up the slack, and is also slated to be phased out.
I'm not optimistic about the BE-4's (I suspect ULA will end up going with an Aerojet engine), and they may ditch the engine recovery aspects, but I fully expect to see _some_ sort of new launch platform by the end of this decade. They don't have a whole lot of other choices...
Uh, the Mexico thing may not be commonly known, it turns out. The chute failed to deploy properly on a mission in '74, bounced off a C-130, and slammed into a field in Mexico, but the payload canister was still intact. It's apparently commonly written up as a UFO sighting called the "Coyame Incident".
I'm underwhelmed, and not surprised. Typically for the big, slow defense industry players, they're planning a more complicated system that does less and will not be ready until 2019.
Meanwhile, SpaceX will be attempting to land their entire first stage again this afternoon.
I think it is more nuanced than simply ULA's system is more complicated. I do however thing that the ULA system is a primarily-mechanical solution while SpaceX is using a primarily-computer based solution.
Background - I have a BS in mechanical engineering, work professionally as a software engineer now, and spent a few years in the defense industry working on nuclear submarines.
Both approaches have key mechanical and computer/control challenges. However ULA's primarily relies on increased mechanical complexity with relatively simple computers. They are adding separation between the tanks and the engines in the first stage. This is relatively proven tech - we separate stages all the time - but it will complicate the piping and structural design of the first stage considerably. There are also mechanical components related to the hyper cone and the parachutes. The whole thing then follows a relatively simple trajectory and then relies on the skill of human pilots to capture the falling engines. We have done this, but again they're using mechanical systems & proven techniques to recover the engines.
Meanwhile, the Falcon 9 doesn't use a whole lot of extra mechanical components to be reusuable. Arguably the only extra bits are the legs and the grid fins. The grid fins are very simple. The legs are a bit more complicated, but probably less than what it takes to separate the entire engine assembly. SpaceX puts all the complexity in the control software. The engines are re-firing multiple times, and during the last few minutes of landing the computer is doing some serious work to balance everything out. At the end of the day, there is no human interaction on the landing.
You often see this trade off between mechanical complexity and software complexity in systems that bridge the domains. I'd personally bet on the company using the primarily software driven approach nearly every time. Software is hard, but mechanical systems are even harder. The economics of software are also way better. Manufacturing costs are pretty much linear to number of rockets, there isn't that much scale in the current market to reduce unit costs. Software costs are relatively fixed compared to number of launches, plus lead times are dramatically different.
You perfectly expressed what I feel (and tried to say in my comment below).
To emphasize on "always bet on software": As seen on the landing video of the (marginally failed) attempt today/yesterday, they are having issues with the dampening of their control software during precision landing. While the field of control software is hugely complex, once the parameters are known, it is trivial to set these values and (later) tweak them. You cannot do that with a (largely) mechanical system. Furthermore, it's easier to run simulations with different sets of control parameters than redo all the FEM-et-al. stuff needed for a modified mechanical design.
If ULA wanted to take a slighly different approach than what they proposed here (e.g. when the first tests don't work as expected), they'd basically need to redesign the whole propulsion "stage". SpaceX can alter just their software.
[As always, it's not black-or-white. ULA may also fix (most of) their issues with software updates. SpaceX may need to add more fins or legs, re-distribute weight, or require more fuel for the landing. That does not invalidate the point above, though.]
Correction: It seems that the tilt maneuver at the end is intentional[1] to not hit the barge full force if something goes wrong. Instead, the control system did not account for (all of the) lag in the propulsion system (time between command and applying force).
Why use a helicopter, when a system like the Fulton surface-to-air-recovery system already exists? Inflate a balloon from the top of the parachute, use a C-130 to grab the line.
NASA's Sounding Rocket program used to use a system similar to the CORONA that you mention below. To my knowledge, it was retired due to the high risk nature of the recovery; there was at least one close call involving the chute line and a propeller.
Now the payloads that need to be recovered are just sealed to prevent saltwater contamination and fitted with flotation aids and dye markers so a recovery team can find them.
Speaking of moving vehicles and people in the sea - the UK SBS have a rather interesting technique for divers getting picked up by a moving submarine.
The divers wait in two teams separated by a line, they notify the sub that then raises its periscope and steers between the two groups snagging the line. The divers then climb along the line to the sub.
[NB This was what they were doing ~1970 according to Paddy Ashdown]
Thinking about it, it might be a weight constraint to cause them to use a helicopter. The sudden capture of an object weighing a few thousand pounds by a plane flying 350 mph could be too dangerous.
The major difference between Corona and Fulton is that Fulton is not mid-air (and therefore involves the thing being retrieved getting a saltwater bath).
There are some pretty big helicopters out there that wouldn't blink at picking up a load like this. The Chinook is used for cargo transport quite frequently: http://en.wikipedia.org/wiki/Boeing_CH-47_Chinook
Interesting concept, but – as others said – it seems rather hacky. Sure, from one engineering perspective it's straightforward to only collect the engines. Others say that re-assembly and especially the proposed collection process adds its own complexity.
I think that the collection process is more involved (concerning number of "moving parts", i.e. requiring a number of independent systems to work in perfect synchronicity) than what SpaceX does. The F9R does have a more complex navigation and guidance system due to the landing option. But apart from the fins and legs[1] (which are of minor complexity), there's no additional subsystem required for the landing capability. Everything's already there and used in other parts of the launch – including major parts of the landing navigation and guidance system. And SpaceX could launch another F9R with the same 1st stage on the same day – ULA would need days, at least.
So I think ULAs approach is over-engineered and does little to improve on the idea of launcher reusabilty.
[1] Actually, the legs may be used before launch in the future, so one less surplus subsystem ;)
It is an interesting approach by the ULA, but I have concerns.
From [1]:
Vulcan, slated for its maiden launch in 2019, will be powered by either a pair of exotic Blue Origin BE-4 liquefied natural gas main engines for 1.1 million pounds of thrust or two conventional Aerojet Rocketdyne AR-1 kerosene powerplants for a million pounds of thrust.
I'm also concerned about using fewer larger engines. While this can be more reliable (less moving parts means less chance of failure), it also means there is no engine-out capability to continue the mission. This also means a lower production volume, which means higher cost per engine, all other things being equal (which they aren't).
The word 'exotic' also gives me pause.
At any rate, it should be interesting. I hope they post testing videos!
What do you mean by fewer? Vulcan is replacing the Atlas and Delta platforms. Both use a single engine per core (the Atlas uses the Russian RD-180, while Delta uses Aerojet's RS-68).
This will actually double the number of engines they're using.
This is unimpressive at best, and impractical at worst.
Rather than ULA expending the intellectual effort to build the control and guidance systems needed to land the entire rocket as SpaceX does, they took the lazy route and added a few steps to their existing process.
The fact that they're willing to suggest that something like this is innovative is just further proof that the entire ULA is staunchly resistant to change. I'm not entirely sure this system will even have a chance to be used.
Doesn't this mean there will need to be a dynamically detachable connector between every fuel/gas line and every electrical wire that runs between the tank and the engine?
Isn't that introducing quite a few potential points of failure? Or was this all thoroughly solved in the 60s and is boring and not an issue?
Doesn't this mean there will need to be a dynamically detachable connector between every fuel/gas line and every electrical wire that runs between the tank and the engine?
Isn't that introducing quite a few potential points of failure? Or was this all thoroughly solved in the 60s and is boring and not an issue?
This happens at lift-off for all rockets. The rockets are fueled at the pad, and the connections stay attached until the last moment.
This kind of thing was also done with the Space Shuttle.
No. They could add pyro separators and moving knives (as the Apollo LAM used). They just need to be able to easily replace the "last few centimeters" of plumbing/cables, but it does not have to be dynamic.
Either way, this (IMHO) adds more complexity to the stage and(!) processing compared to what SpaceX does (where complexity is mostly added in software).
1.) It's good to see ULA stepping up to the plate and actually innovating. SpaceX will need some competition by then, to keep the industry healthy.
2.) The name, "Vulcan", is pretty badass. Certainly far better than the other, embarrassingly jingoistic candidates they were considering.
3.) The inclusion of innovative NewSpace companies like Blue Origin and Xcor is pretty exciting, even if ULA hasn't actually committed to using their technologies yet.
That said, there are ways in which the Vulcan seems like it was designed by a committee, and doesn't quite seem fully-baked. In particular: the "dial-a-rocket" approach of strapping on solid boosters is at fundamental odds with the economics of reusability.
In an expendable rocket, solid boosters are used because you need a lot more thrust early in the ascent (to overcome gravity losses), and solid rockets are a relatively cheap way to achieve that. (Solids generate a lot of thrust during a short period of time, but their efficiency over long-duration burns is relatively poor, which is why they're generally not used all the way to orbit). You could accomplish the same thing by using more liquid fuel and more engines in the primary booster stage -- but turbopump-driven liquid engines are a good deal more expensive than solid boosters, so it doesn't make sense to do this if you're going to dump them in the ocean after a minute or two.
On the other hand, if you're recovering the engines, then using more of them is absolutely the right thing to do. In that case, the tradeoff isn't between the cost of liquid engines vs. solid boosters; it's the difference between the cost of refurbishing liquid engines (and some extra fuel) vs. solid boosters. In this case, the latter is likely to be more expensive by an order of magnitude. So if your hardware is reusable, then it's better to have one or at most two vehicle configurations, and simply accept that most of the time your vehicle will be oversized for its payload. You also get some additional benefits from doing this, such as greater mass-produceability and engine-out capabilities, etc.
I suspect that the problem is that aerospace engineers are used to doing high-level trade studies using a crude $$$/kg costing for the cost of a rocket -- at least, this is how I've frequently seen them do it. If this is how you think, then you want your vehicle to be no larger than the payload requires -- and that's what the dial-a-rocket approach allows you to do. But it's kind of like assuming that a truck costs $$$/kg, and therefore if you need to carry a load across town, you should build a truck which is as large as you need and no larger. This makes sense if you take it as a given that you will always be building your trucks by hand, and that they will be thrown away after every journey. But if both of those assumptions are false, then so too is the "build the truck to fit the payload" design philosophy.
It doesn't look like ULA has figured this out yet -- but they've definitely realised that there's a fire under their tail, so hopefully they will do so eventually!
Yeah, I don't get the sense that they're trying hard enough to optimize the operational cost that well.
The SpaceX approach sacrifices performance, in the sense that you need to leave some (heavy) fuel in the tank for recovery. That is delta-V that you could use to loft a heavier payload.
I'm impressed by the SpaceX approach in general. They're using and re-using the most proven technologies in an innovative way. I think powered landings are the way to go.
I think the distinction is important, especially for a headline. They aren't capturing the full rocket, just the rocket engine. That's a much lighter load to capture, and likely much more feasible than catching a full rocket.
I understand there is some engineering rationale provided, but it seems to me just like showing off, a spaceflight version of "longest e-penis" competition. "You can land your rocket at a ship? Well, then we'll catch ours mid-air!".
Seems kinda hacky, instead of investing the time & money needed for full reusability, they'll do a fraction of the work and hope for a successful helicopter recovery, which seems kinda hard. I know they tried a capture like that with some probe and it failed.
I can't figure out it that's brilliant or stupid.
Catching things falling from space is actually something that was done pretty regularly in the past. Before we had digital imaging sensors spy satellites had to rely on film. Orbiting imaging platforms would 'drop' film canisters, which would be caught by waiting aircraft, and flown back to a processing center to be developed.
The headline aside their approach is actually more "conservative" than SpaceX. Breaking off pieces of the rocket instead of piloting the entire rocket back to earth.
"Vulcan will be partially reusable (eventually)"
Haha what a joke. The whole point of reusability is to be able to land the rocket, refuel it, and send it back up the next or even same day!
"ULA says it's going to try to capture only the most valuable parts of a rocket"
So... how about when we fly NY -> LA in our 777 we only bother to land the passengers in the remaining "valuable" parts of the airplane? See the point ULA? We're trying to make spaceflight just like commercial airline traffic. That's the ONLY way to make it commercially viable. Your cost-plus methods of building expensive as possible single use bottle rockets are over man!!
Also interesting is the reasoning behind capturing parts of the rocket (and it is only parts) in midair. ULA say this is because the expensive bits are small, and essentially imply that they can get most of the 'wins' with not much effort when compared to SpaceX's "land it on a boat" approach. This may well be true but it seems SpaceX's approach is thinking in wider terms of the re-usability required for frequent space flight, rather than cheap space flight.
I have a keen interest in space flight and SpaceX in particular, so take my opinion with a pinch of salt, but this article reads to me like SpaceX are well over a decade ahead of the ULA, much more forward thinking, and overall the more exciting player in the commercial space-race.