Getting metal hunks into orbit used to cost a bomb. Then SpaceX's Falcon 9 landed Monday's historic landing of the first stage of SpaceX's Falcon 9 rocket is possibly the most significant event in rocketry since Apollo 8 showed we could get humans to the Moon and back safely. Landing from helo https://t.co/dYomRtG0Xs — SpaceX (@SpaceX) December 22, 2015 The Falcon rocket's first stage is hugely important …
Well, cautiously optimistic. It would be interesting to see their projected figures on the additional cost of engineering a launcher that can be re-used, the lifetime of re-use, and projections if the number of re-uses (with and without landing snafus). I suspect it might be confidential though :-)
They will figure it out. They'll make the unavoidably expendable pieces inexpensive and quick to replace. They'll analyze the structure of every piece to determine the stresses it has undergone and remove the bits discovered to be excess. They will spend more on the parts that need changed less often. It will be made faster, cheaper, more reliable and produced in more volume. Now that they have a sample of a used orbital booster that lands, they have what they need to build one that does so every day. This was the invention - the "Eureka!" Moment. What follows is iteration, improvement, refinement. It is the Wright Flyer of reusable orbital boosters - just barely enough to survive the landing and prove the concept. What comes next from this group is the 737 of reusable orbital boosters - the pickup truck of the next generation.
Everybody else in the space launch industry had best get cracking, because SpaceX is not just undercutting them by half - they are getting a free reusable orbital booster out of each launch deal as well. That is going to break their business model. They are in the horse buggy business. That is what makes me the most excited. The gold rush is on!
Knowing it can be done is the biggest deal. Once it is known to be possible, greed and competitiveness will take us the rest of the way. No doubt in China, Russia, India, Europe are government agencies in emergency meeting to discuss how they can get in on this before the Americans claim the whole cosmos for themselves. Man is finally going to get off our little mudball and start claiming our destiny.
They will figure it out. They'll make the unavoidably expendable pieces inexpensive and quick to replace.
The bits that are most prone to trouble are the turbo pumps. These are effectively the only moving parts in the whole propulsion chain, and they get a hell of a hammering. It took NASA a lot of effort to get those right on, well, every engine they've ever had, especially the Shuttle. They're far too expensive to be expendable, and are also a key part of the innards of the engine.
I don't know why people are getting so worked up about the knowledge now 'available' to SpaceX following this flight. You don't need to fly an engine to see what it looks like after a burn, you can pretty much do that all on the ground on a static test. They probably already know roughly what maintenance work is required to re-use the engines. All SpaceX need to do is see if the flown engines match static test engines.
And assuming that every engine is static fired anyway before it flies, every engine in a sense has already gone through the required maintenance regime to return them to flyable condition.
[As far as I'm aware the only engines in the history of space launches that weren't static fired before flight was some of the upper stage motors on Ariane 4, later on in the lifetime of that launcher. They had become so good at making them (they traced their origins back to Blue Streak) that there was little point in test firing them. Maybe the Russians don't bother any more either, given the age and success of their design.]
I suspect that SpaceX will very interested in how the structure of the 1st stage has coped with the battering it's undergone in making an about face turn, a slightly slowed ballistic return followed by some sharp deceleration just prior to landing. There's also the acoustic and heat loading it will experience on landing on a flat concrete landing pad. On a launch pad these are taken away by the flame trench (I don't know if SpaceX use sprayed water to suppress the acoustic load). On the plus side the amount of thrust needed to land is way less than that to take off - there's a lot less weight!
The first stage doesn't achieve orbit and so doesn't have the same heating problems of re-entry that an orbiting craft would. In fact it has completely reversed direction from the launched orbit, so there is none of the orbital energy left. it then slows its reentry by burning the rockets again.
I would think that lower atmosphere airflow cooling is the biggest difference between flight and static test.
What heating? The booster slows itself to near zero horizontal velocity before re-encountering the atmosphere. It's pretty much straight down from there(*) and not particularly fast when it's doing it.
These units are _not_ coming back in from orbital velocities.
Aerodynamic stress I'll give you but this is much less than the stresses imposed by boost phase.
(*) All the boosters have to do is "stop" - the earth's rotation brings the launch site back under them, so they don't have to backtrack the 50-75 miles they've gone downrange.
Hey, I'll be pleased as punch if they get it to the month in, month out stage! The Shuttles were supposed to keep up that hectic schedule yet we rarely launched them more than once every 3 months even when we had a fleet of them.
Not that I'd object to a week in, week out schedule.
Falcon 9 has landed before, just only from small test flights until this week.
Also, I doubt these engines will ever fly again, or the next few flights either. But knowing SpaceX, they'll learn a lot from them on how to make engines that can fly over and over, then watch the prices drop.
...is my opinion of the article! Not so good, Vulture central!
At least now we have, for the first time ever, a first stage that successfully boosted a delivery to it's intended orbit, and got it back in one piece, able to analyse exactly what happens to the engines! And if it becomes obvious from that analysis that the engines are not really reusable right now, we at least get to learn how to build them better to make them properly reusable...
Nobody has ever done that before, so it's hats off to SpaceX!
Elon Musk's idea is that by landing and refurbishing the rockets he uses, the cost of orbital delivery can be slashed.
I am not convinced that it was his idea. The first person to publicly propose it was probably Max Valier in the 1920s. The first stage of the Space Shuttle, the two solid rocket boosters, certainly were re-usable, and re-used, although they were detached at about 50 km up, instead of 100 km for the first stage of this rocket. Nevertheless they contributed about 70% of the total mass of the vehicle at launch.
SRBs are basically a metal tube.
There's very little in them that's breakable - other than gaskets that were expected to be replaced every time.
Liquid engines are really expensive with loads of fiddly bits to go wrong.
They are aiming to get 30 launches out of each engine. If they get a 10th of that, it's a gamechanger.
SRBs are basically a metal tube.
There's very little in them that's breakable - other than gaskets that were expected to be replaced every time.
They've also got a lot more power. Simple, cheap, and a huge amount of grunt - what's not to like about them?
They do have one major disadvantage - they're not smooth burning. If you've got a lot of SRBs attached to your launcher you get a rough ride whilst they're burning, and it gets rougher as they burn (there's less weight to be shaken about). That's not necessarily a problem, you simply tell your customers how strong their satellites have to be. However, it is an unwelcome complication.
TWO major disadvantages: when a solid goes boom, it does so extremely quickly with no warning, like a firework. Bang. You're dead.
Liquids give you not only quite a bit of advance warning, since you're monitoring all sorts of vital signs, but they also have the ability to shut down, giving you a little more time to abort.
G Cash offered, "...when a solid goes boom, it does so extremely quickly with no warning, like a firework. Bang. You're dead."
You realize that they set fire to SRBs, like a firework, intentionally at launch? That's how they work.
Are you concerned that they'll start burning from the top end too?
The SRB on the Challenger did not go boom. It just leaked a bit. It was the External (liquid fuel) Tank, specifically its recent contents, that sort-of went boom after it disintegrated.
The fundamental point here is quite simple:
SRBs are *already* on fire. They're pretty much immune to going 'boom'.
Using the phrase 'going boom' in the context of an SRB indicates ZERO knowledge about SRBs.
Obviously.
"The SRB on the Challenger did not go boom. It just leaked a bit."
It went boom eventually - when the range safety officer fired the destruct mechanism that split the booster along its length.
Mind you that was several seconds (and several tens of km) after Challenger had self-destructed as a result of going sideways at high mach numbers.
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"the two solid rocket boosters, certainly were re-usable, and re-used,"
Well, yes and no. Bits of them were re-used, ie most of the steel casing. After being completely dismantled and rebuilt from the ground up. All of that expensive recovery work was PR to imply it was cheaper. I doubt they even broke even on the recovery/"refurbishment" process compared to just building a new SRB from scratch.
"All of that expensive recovery work was PR to imply it was cheaper."
Not to mention that congressional pork resulted in the things being built in Utah, which automatically limited their diameter to what would fit in railway tunnels.
The original proposal was for the boosters to be built somewhere along the gulf coast and barged in. Doing that would have allowed them to be much bigger - and the original liquid rocket design was intended to be "fly home"
Shuttle was a clusterfuck built on top of a camel - the F35 of its day.
Speaking of XKCD, after Bezos' Shepard landing, Elon musk tweeted a link to Mr Munroe's website:
- "Congrats to Jeff Bezos and the BO team for achieving VTOL on their booster"
- "It is, however, important to clear up the difference between "space" and "orbit", as described well by https://what-if.xkcd.com/58/ "
[ https://twitter.com/elonmusk/status/669129347555430400 ]
He wasn't snarky, either.
You you sell it to the MIC for doing rapid intervention for "Ballistic Space Marines", whereby once the Commander In Chief is appraised of the likely bayesianically-calculated presence of an Axis of Evil member in the Sandlands in the middle of the night and gives his mighty Go-Ahead for Operation [INSERT BOY SCOUT CODENAME HERE], they will land on top of the baddie in 15 minutes flat.
MIC dicks going hard!
For a start the Falcon 9 first stage has to leave fuel unburnt to power it's descent. That's fuel not available to boost the second stage higher, or to put it another way is mass taken off the rest of the payload. You end up with a much bigger, and hence more expensive, launcher than a non-reusable one for the same payload.
Then there's the reusability issue. Engines, pumps etc engineered for multiple use are going to be more expensive and probably heavier than one-shot equivalents, and (as the article says) will need a lot of expensive inspection and refurbishment between launches to ensure they're as reliable as new ones.
I'm not saying the economics won't make sense, just that it's not a given that reusable=cheaper. If an article is going to call itself "analysis" then I suggest it needs some facts and figures to back up its "slashing costs" claim.
Not all payloads are the same - the largest payloads will always require the first stage to be forfeited, but slightly smaller payloads afford the spare capacity for some 'descent fuel' to be carried as well.
(Slightly lighter payloads don't have enough spare fuel to return to base, hence the barge landing option)
Of course given the cost of the stage it might be more economical to split the big payload in two and assemble it in orbit?!
As for designing things for reuse - it's a good thing that cars are single use items... and planes... and bikes.... and shoes....
Oh, wait a moment.
They don't have to be very much heavier, certainly not when compared with the all up mass of the rocket.
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