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Elon Musk’s SpaceX Is Testing Technology To Make Rockets Reusable

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Re: Elon Musk’s SpaceX Is Testing Technology To Make Rockets Reusable

#11

Post by InclinedPlane »

stcredzero wrote: post #9
InclinedPlane wrote: post #5

Earlier quoted context omitted.

Aerospikes are oversold. NASA and LockMart tried to prove the technology with X-33/VentureStar and it proved to be far, far less promising than it looked initially. Also, the idea that we need some new technological silver bullet to advance spaceflight has been a pernicious impulse in the spaceflight community since its inception, and it very much has not helped. We don't in fact need any breakthrough technology, jus…

> We don't need anything more than perseverance and pragmatism to revolutionize access to orbit, and thankfully some companies are doing that. Jerry Pournelle and many, many others had been saying that for decades. Just keep on building rockets, do it a lot, with the principle that "practice makes perfect" in mind. Instead, governments were just paying contractors to mostly do the same thing for cost-plus, with only…

In the US at least we put all our eggs in one basket (the Shuttle) and ended up foregoing about 2 decades of development in conventional launch vehicles (until the Challenger accident forced some sanity). Also, a lot of the big aerospace companies (such as Boeing) have surprisingly shallow experience with orbital rocketry (although it's improved a bit with the EELV generation). Very few folks at those companies actually had hands on experience with building or flying rockets, and even less experience with testing (as a rule most launch vehicles fly straight down the middle of the flight envelope as much as possible, so even in a vehicle like the Shuttle with 130+ flights that's nowhere comparable to having the same level of understanding or confidence in the vehicle if it had flown that many flights while exploring the envelope).

Re: Elon Musk’s SpaceX Is Testing Technology To Make Rockets Reusable

#12

Post by vegardx »

gregpilling wrote: post #7
trothamel wrote: post #6

Here's the video of the most recent SpaceX Grasshopper flight: http://www.youtube.com/watch?feature=player_embedded&v=2... (via: http://forum.nasaspaceflight.com/index.php?topic=30708.msg10... . May not be available in some areas due to music licensing.)

That was pretty cool. Why was I the 314th person to watch it. Surely there must be more interest in rockets like the Sci-fi books always described? In most books, the rockets came down like the Grasshopper.

There's a good reason for it, and usually is a sign that the video is immensely popular. You can find out why on Youtube it self: http://www.youtube.com/watch?v=oIkhgagvrjI

Re: Elon Musk’s SpaceX Is Testing Technology To Make Rockets Reusable

#13

Post by jnw2 »

InclinedPlane wrote: post #3
deadairspace wrote: post #2

This impressive video from Armadillo is three years old. I wonder what they are up to now. http://www.youtube.com/watch?v=9u0qlIoSSkQ

Right now there are several companies working on reusable launchers. SpaceX, of course, who already has a proven expendable orbital launcher. But also Blue Origin, Armadillo, XCOR, and Virgin Galactic. None of those companies have an orbital launch vehicle but each is working on building the foundations for reusability in the form of pioneering various control mechanisms (vertical landing being one) as well as engine…

If Virgin Galactic can get the costs down enough, the really exciting thing about what they are proposing to do is turning 18 hour airplane flights into less than two hour suborbital flights. Even if you don't care about space for the sake of space, it's obvious that that would be a huge improvement in transportation between various points on Earth.

Re: Elon Musk’s SpaceX Is Testing Technology To Make Rockets Reusable

#14

Post by stretchwithme »

InclinedPlane wrote: post #11
stcredzero wrote: post #9

Earlier quoted context omitted.

> We don't need anything more than perseverance and pragmatism to revolutionize access to orbit, and thankfully some companies are doing that. Jerry Pournelle and many, many others had been saying that for decades. Just keep on building rockets, do it a lot, with the principle that "practice makes perfect" in mind. Instead, governments were just paying contractors to mostly do the same thing for cost-plus, with only…

In the US at least we put all our eggs in one basket (the Shuttle) and ended up foregoing about 2 decades of development in conventional launch vehicles (until the Challenger accident forced some sanity). Also, a lot of the big aerospace companies (such as Boeing) have surprisingly shallow experience with orbital rocketry (although it's improved a bit with the EELV generation). Very few folks at those companies actua…

When government does something, it tends to put all its eggs in one basket.

And the way lobbyists run our government makes the problem even worse, as there's more pressure to keep spending regardless of results.

Re: Elon Musk’s SpaceX Is Testing Technology To Make Rockets Reusable

#15

Post by quotemstr »

jnw2 wrote: post #13
InclinedPlane wrote: post #3

Earlier quoted context omitted.

Right now there are several companies working on reusable launchers. SpaceX, of course, who already has a proven expendable orbital launcher. But also Blue Origin, Armadillo, XCOR, and Virgin Galactic. None of those companies have an orbital launch vehicle but each is working on building the foundations for reusability in the form of pioneering various control mechanisms (vertical landing being one) as well as engine…

If Virgin Galactic can get the costs down enough, the really exciting thing about what they are proposing to do is turning 18 hour airplane flights into less than two hour suborbital flights. Even if you don't care about space for the sake of space, it's obvious that that would be a huge improvement in transportation between various points on Earth.

Yes, but if you can afford a suborbital flight, you can probably afford to spend those 18 hours in international first class, where you'll have access to a bed, unlimited champagne, caviar, and whatever else you want. Why cut that party short?

Re: Elon Musk’s SpaceX Is Testing Technology To Make Rockets Reusable

#16

Post by InclinedPlane »

gregpilling wrote: post #7
trothamel wrote: post #6

Here's the video of the most recent SpaceX Grasshopper flight: http://www.youtube.com/watch?feature=player_embedded&v=2... (via: http://forum.nasaspaceflight.com/index.php?topic=30708.msg10... . May not be available in some areas due to music licensing.)

That was pretty cool. Why was I the 314th person to watch it. Surely there must be more interest in rockets like the Sci-fi books always described? In most books, the rockets came down like the Grasshopper.

In short, there are two algorithms for counting views on youtube videos. There is a simplistic algorithm which calculates views up to 300, then there is a more complex algorithm which kicks in that is more thorough. This has the consequence of temporarily freezing the view count for very popular videos at 300 + how ever many different worldwide regions (google-wise) got in that last view effectively simultaneously.

Re: Elon Musk’s SpaceX Is Testing Technology To Make Rockets Reusable

#17

Post by eksith »

InclinedPlane wrote: post #5
eksith wrote: post #4

It doesn't have an aerospike engine. The first leg of the journey is always the hardest at sea level so if they can use less fuel there, it will be easier on the rest of the trip. Aerospikes are more efficient at lower altitudes and offer a greater throttle range (since each burner can be independently controlled). Whether this is a multi stage or single stage, an aerospike is something they need to look into. It's b…

Aerospikes are oversold. NASA and LockMart tried to prove the technology with X-33/VentureStar and it proved to be far, far less promising than it looked initially. Also, the idea that we need some new technological silver bullet to advance spaceflight has been a pernicious impulse in the spaceflight community since its inception, and it very much has not helped. We don't in fact need any breakthrough technology, jus…

Aerospikes aren't radically new.

If you think about it, the Russians have gone half way with their trademark multi-chamber rocket engines since the 1960's as well. The difference is that there are more burn chambers and they're arranged around a central plug.

I.E: http://www.csulb.edu/colleges/coe/mae/views/projects/rocket/...

The central basis of the aerospike has been around for decades. It's not as old as the traditional bell, but it's not only as old as the X-33. And their problem was a radical overall shape including the fuel tanks, plus a lot of other unproven technology. The engine concept was still sound.

How come we don't all fly around in 1960's aircraft designs? Some people do, but not all of us. How about 1960's car designs? Computers? Sure, we use a lot of the same principles, but these are worlds apart for a reason.

The aerospike isn't exactly a silver bullet, so you'll still have multiple stages, drop tanks etc... but capacity without burn efficiency doesn't mean much improvement.

Pragmatism doesn't mean sticking to something cause it ain't broke. If there is a genuinely better way to do things, then it should be explored.

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