In one sense, ULA is playing the tortoise to SpaceX’s hare. Musk was first out of the blocks with development of reusable rocket boosters, but Bruno believes ULA’s Vulcan, with reusable first stage engines, makes the most sense financially given current market projections. He said the Vulcan’s engines represent two-thirds of the cost of the stage. Under ULA’s approach, the engines will be recovered and reused after every flight. SpaceX’s design calls for recovery of the entire rocket stage. Depending on the weight of the payload and the requirements of its orbit, that cannot be done on every flight.
“It boils down to as simple as this: is it better to recover 100 percent of the value of the booster some of the time or only two thirds of the value of the booster all of the time?” Bruno said reporters during a roundtable discussion earlier this week. “Well, that depends on how often you get a big, heavy payload. We’ve each made market forecasts, and if we’re right, our solution will be economically advantageous. If I’m wrong and they’re right, then theirs will".
To recover the Vulcan engines, a small pod housing an inflatable heat shield and a gas generator will be mounted on the bottom of the first stage. After boosting the rocket out of the lower atmosphere, the engines will shut down and the propulsion section will be disconnected, allowing it to fall free. The heat shield, based on NASA technology, then will inflate using the gas generator, protecting the engines from the heat and stress of atmospheric entry. Once clear of the plasma heating region, a parafoil will deploy to fly the engines to their planned pickup point.
All sounds rosy so far...
A large helicopter then will swoop overhead...
Wait, what ?
...snagging a cable to capture the engine package, which will be lowered to the deck of a nearby salvage ship. A similar technique was used to capture film canisters ejected from Corona spy satellites in the 1960s.
Well, err, OK, but that I would very much like to see.
Recovering the engines non-propulsively will allow the Vulcan to use virtually all of its propellant to put the payload into the best possible orbit “for a pretty modest weight penalty, you know, the weight of a parachute, the weight of the subsystem,” Bruno said... the entry environment behind the heat shield is much more benign than what a Falcon 9 experiences with its tail-first propulsive descent and ULA engineers expect engine refurbishment to be a relatively straightforward affair.
https://spaceflightnow.com/2018/03/20/ula-touts-new-vulcan-rocket-in-competition-with-spacex/
I like Tory Bruno.
ReplyDeleteBut ...
the institutional thinking at ULA (consortium of Boeing and lockheed -Martin) is based on over 60 years of cost plus contracting so truly revolutionary ideas that don't necessarily maximize the bottom line are elusive.
Elon has the luxury of a clean slate and a mission to potentially save humanity. The boatloads of cash are just a side benefit.
Helicopter retrieval has been done before, but historically it has had mixed results. I like the approach if it can be perfected, though.
ReplyDeleteIsaac Kuo Why can't they just parachute all the way to the ground...?
ReplyDeleteMatter Beam It sounds like they need a drone ship (or similar) to collect the engine. I guess they want to fly over sea to minimise risk of errors over populated areas. And presumably, like Space X, they want to prevent the engines from getting contaminated with salt water.
ReplyDeleteMatter Beam Helicopter retrieval dramatically reduces the size/mass of the parachute, because it's okay to have a large terminal velocity. Historically, this has been important for deep space sample return missions.
ReplyDeleteThe bad news is that if the helicopter fails to catch it (there's enough time for maybe 3 passes), the payload crashes into the ground at high speed. Historically, we have still managed to get some samples despite this. (For delicate precision rocket engines, though, it would be a total loss.)
Rhys Taylor For this purpose, the engines would indeed be returning over the Atlantic, but this is not a choice. KSC was purposefully developed as our launch site so that there would be no populated areas to the east (which is the direction of the orbits generally used because Earth's spin gives a significant boost in that direction).
Even if ULA wanted to land the engines on land, there simply isn't any land in the middle of the Atlantic to land on.
If there were land, though, then a possible strategy would have been to use a combination of parachutes and small retrorockets. This is what Soyuz uses. That way, it's okay to have a pretty large terminal velocity but the retrorockets fire just before impact to bring the capsule to a safe landing.
Hmm the main downside (apart from catching it mid-air) is obvious - you have to carry the heatshield every time with you.
ReplyDeleteWe will see how good or bad idea this is.
Anyway I think when you want to keep things simple stupid, and you should when you can, the helicopter idea is pretty bad - even if it worked 100%.
I'd suspect a film canister weight much less than the engine they're thinking about catching, which will make for a more difficult catch with more potential to stress the airframe of the helicopter.
ReplyDeleteThere's no mention of robotic helicopters, so you're putting the aircrew in danger, when SpaceX's barges are unmanned. In addition to the airframe stress (probably addressable), the cabling required for holding that sort of weight would be strong enough to endanger the helicopter blades.
In any case, their whole argument is based on an outdated model of SpaceX operations. SpaceX originally flew expendable missions because the booster didn't have the performance to deliver large payloads to high energy orbits. But as SpaceX has refined their landing technology and improved and upgraded the Falcon 9, this has applied to a smaller number of payloads, and of course, Falcon Heavy is now flying, and will deliver large payloads AND recover all the booster stages (the second stage is still not reused, and that isn't likely to change unless BFR development stalls considerably).
ReplyDeleteSpaceX continues to fly expendable missions largely, at this point, to make use of older-generation booster cores that they'd like to get out of the way anyhow, and they can continue to be used for various reentry and high-risk landing experiments as well. It's the space equivalent of a clearance sale.
So a lot of what they're saying is smoke and nonsense. I'm skeptical about the whole helicopter recovery thing, and the overall economics. ULA MAY find a window of opportunity to operate for a while, assuming they can get this thing up and running fast (of which I'd be shocked). And they'll be able to keep running for a bit as long as the DoD needs a backup launch supplier. But if Jeff Bezos and Blue Origin are flying soon (I just saw their huge new building just beyond the Kennedy Space Center gates) and can get DoD certified, then the ULA plan is just toast. Complete toast.
They should be looking to leapfrog SpaceX and Blue Origin, or at least, match them in a dead heat. By trying to come up with an also-ran to technology that's already in the course of being supplanted and offering half-assed rationalization, ULA is betting on SpaceX's failure. That might have been half sensible a decade ago, or maybe even five years. Now it's just stupid.
I'm really skeptical of Blue Origin. So far, they've only flown hardware suitable for suborbital flights, and this hardware has no commonality with what would eventually used for orbital flights. Classic strategy error, which has already sunk others. In contrast, SpaceX had a strategy revolving around flexible commonality of hardware going forward.
ReplyDeleteAs for ULA's strategy - I think they're going for what they can realistically accomplish. Trying to leapfrog is a foolish strategy if the chances of being able to leapfrog are low. What could they do in order to leapfrog? A big dumb booster is a bad bet. Like it or not, SLS isn't going anywhere, and chances are SpaceX would be able to beat any competitor to the punch with BFR.
What else could they try? Spaceplane of some sort? REALLY bad bet, considering the technology challenge and the long history of failed spaceplane projects.
No, they need to go where the money is, and the money's in relatively small satellite payloads on the order of 10 tons or less. In that regime, how the heck is ULA or anyone else supposed to "leapfrog" Falcon 9?
I have my own pet ideas for cheaper launch costs, but they're all very high technology risk compared to helicopter recovery of boost engines.
I'm not sure about Blue Origin either, based mainly on their tendency towards secrecy that makes "playing it close to the chest" SpaceX seem like an open book. But they seem to have developed a pretty good next-generation rocket engine (which ULA is going to use) and New Shepard is a clever design that works, even if it seems to have little connection with what Bezos says he's aiming for.
ReplyDeleteBut they clearly have good engineers working for them, like SpaceX, they have the huge advantage of a clean sheet to build from, no established structure to restrict development, and they have LOTS of money.
So, I'm reasonably sure they're going to fly. The question is, when, and how many problems will they face on the way there. Bezos would clearly like to catch up with SpaceX, or even maybe surpass them in some ways, but that's a huge challenge.
It helps that his ultimate goals only somewhat overlap Musks. Bezos wants to get us into space, but perhaps not (at first) too far. Musk is laser-sighted on a Mars colony, with everything else a stop on the way, a means to an end, or a distraction to be avoided.
That leaves a lot of ground for another next-generation launch company to operate in.
One other thought about ULA: This whole questionable enterprise (no pun intended) may simply be a stalling strategy to keep their pieces on the board while they hope for someone (probably Bezos) to sweep in and buy their operation. To me, that's maybe the most credible theory yet.
ReplyDelete