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SpaceX Grasshopper Flies High

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Re: SpaceX Grasshopper Flies High

#51

Post by InclinedPlane »

skorgu wrote: post #11
InclinedPlane wrote: post #6

Earlier quoted context omitted.

The pace of progress seems to have been faster than even SpaceX anticipated. Within the next year we'll see very significant tests of core components of the system and flight profile (for the first stage at least). The very next Falcon 9 flight (out of Vandenberg) will use the performance overhead provided by the v1.1 upgrade to do a controlled reentry of the 1st stage and then after it has reached terminal velocity…

And I haven't been this excited (nay, giddy) since I was about 6 and reading Space Colonies For Kids or whatever. I'm a bit worried about the bimodality of the future but man the good parts are going to be good .

I'm pretty optimistic about the future. The information age is young yet and only recently starting to come into its first full stage of maturity. And there are a ton of very hopeful signs out there, especially in terms of long term trends. I think the chances that things will turn out well are actually higher than not doing so.

Re: SpaceX Grasshopper Flies High

#52

Post by TeMPOraL »

EthanHeilman wrote: post #42
petenixey wrote: post #35

Earlier quoted context omitted.

But why not just use a parachute and airbags? They're going to be a vast amount lighter than the fuel you'd need for a rocket landing.

You can't direct where the rocket ends up, highly likely that the rocket will get damaged or much less likely that the rocket will damage something else (This is why NASA dumps it's rockets over the ocean). Then you have find a way to get the rocket home, which involves time and money. Why not just burn fuel (rocket fuel is only a few times more expensive that burning water) and bring the rocket home? If you need mor…

> highly likely that the rocket will get damaged

And because you don't know whether it is damaged or not (sometimes the damage may not be obvious), it's likely that the rocket will have to get a long post-flight inspection to check if it is suitable for another flight. It's something you can almost completely avoid if you land the rocket gently.

I read somewhere, that the costs of recovering SRBs of Space Shuttle from the ocean and then inspecting and fixing them were many times greater than building another pair of boosters.

Re: SpaceX Grasshopper Flies High

#53

Post by EthanHeilman »

cryptoz wrote: post #40
petenixey wrote: post #35

Earlier quoted context omitted.

But why not just use a parachute and airbags? They're going to be a vast amount lighter than the fuel you'd need for a rocket landing.

You cannot land a large payload on Mars with a parachute due to the very thin atmosphere.

When I first read this I thought you were missing the point, then I remembered Musk's ambition to live on mars and the planned landing sequence for the Red Dragon. Good point!

Re: SpaceX Grasshopper Flies High

#54

Post by derekp7 »

rplnt wrote: post #12
StylifyYourBlog wrote: post #2

Its likely that full-fledged Space Travel with reusable rockets will be possible in the coming years

I believe same thing was done by NASA in the 70s. So not really big step forward in this particular regard. edit: Can't find it at the moment. So far I've found http://en.wikipedia.org/wiki/McDonnell_Douglas_DC-X which did what grasshopper and more almost 20 years back. I still believe I've read something earlier though. Will edit when/if I find it.

Are you referring to that neat trick they pulled a half dozen times, where they landed a rocket on its tail in an airless environment with 1/6 gravity? That was still pretty impressive on a bunch of other levels.

Re: SpaceX Grasshopper Flies High

#55

Post by navneetpandey »

marcamillion wrote: post #39
jessriedel wrote: post #21

For those of you who haven't seen it, here is SpaceX's fantastic animation of their ultimate goal for Falcon 9 (complete with soundtrack by Muse): http://www.youtube.com/watch?v=sWFFiubtC3c This will give you an idea of how grasshopper fits into the full flight plan.

I am not that much of a space buff....but for some reason...when I see this video and the one posted by the OP - I get SOOO excited. Perhaps it is the innovation of never seeing a rocket do a full-blown take-off and then land vertically and then seeing what the long-term result will be - which is orders of magnitude better and more efficient than how it is today....that just gets me excited. But I am truly glad to be…

thats what got me excited, when I watched Elon Musk talking about this project on TEd, since then I am following this project of SpaceX.

Re: SpaceX Grasshopper Flies High

#57

Post by skorgu »

InclinedPlane wrote: post #51
skorgu wrote: post #11

Earlier quoted context omitted.

And I haven't been this excited (nay, giddy) since I was about 6 and reading Space Colonies For Kids or whatever. I'm a bit worried about the bimodality of the future but man the good parts are going to be good .

I'm pretty optimistic about the future. The information age is young yet and only recently starting to come into its first full stage of maturity. And there are a ton of very hopeful signs out there, especially in terms of long term trends. I think the chances that things will turn out well are actually higher than not doing so.

Don't get me wrong, I'm optimistic myself. I'm just a bit concerned about how some poorly defined cohort of 'people who don't read HN' are going to fare; not all of those trends are looking super rosy.

Re: SpaceX Grasshopper Flies High

#58

Post by InclinedPlane »

deepblueocean wrote: post #25
jessriedel wrote: post #21

For those of you who haven't seen it, here is SpaceX's fantastic animation of their ultimate goal for Falcon 9 (complete with soundtrack by Muse): http://www.youtube.com/watch?v=sWFFiubtC3c This will give you an idea of how grasshopper fits into the full flight plan.

I find this confusing. It's awesome, that's for sure. But it seems like lifting all the fuel needed to do a soft landing is inherently a tradeoff for less payload capacity. What is the benefit, then? Is it just so much cheaper to be able to re-use the first two stages?

Almost the entirety of the cost of an orbital launch is in manufacturing and operational costs. Cost of fuel is basically just noise. If you can reduce operational turnaround time and operational complexity, even at a cost of payload, then you'll save so much money it'll be worth it in the long term. SpaceX is aiming for a re-assemble, gas up and go workflow. If they can pull it off it might reduce their per flight launch costs by a factor of 10 in the short term and perhaps as much as 100 if they get really good at it (although that's likely several generations of hardware down the line, at best). With that sort of thing on offer a reduction in payload is easily justifiable.

Imagine if somebody replaced your car with a version that had twice the carrying capacity, but would only run for one tank of gas. It wouldn't be a worthwhile trade would it?

Re: SpaceX Grasshopper Flies High

#59

Post by savrajsingh »

JshWright wrote: post #23
savrajsingh wrote: post #20

Can someone share some details on how the rocket is stabilized? There are a few different ways to do it -- how does this one work?

I assume it's some sort of gimbal control/vectoring of the thrust (since I don't see any 'extra' exhaust further up the rocket)

Yeah I think that's what it is unless told otherwise. Quite impressive stuff!

Re: SpaceX Grasshopper Flies High

#60

Post by InclinedPlane »

petenixey wrote: post #35
EthanHeilman wrote: post #30

Earlier quoted context omitted.

Fuel is very inexpensive (~2% the cost of a rocket launch), rockets are very expensive. If you can trade off fuel for not having to build a new rocket you drop the cost to orbit by orders of magnitude. Additionally you can build more expensive rockets that are more efficient since rocket creation becomes a capital rather than a reoccurring cost.

But why not just use a parachute and airbags? They're going to be a vast amount lighter than the fuel you'd need for a rocket landing.

Parachutes are a pain in the ass to replace. But more than that taking a dunk in the ocean isn't so good for rockets, and spending the better part of a day with a search and recovery team and all the relevant equipment necessary out looking for the rocket and hauling it back home isn't cheap, it also adds a lot of delay to the whole workflow. Compare that to a propulsive landing on the launch pad next to the assembly facilities. You don't have to have a whole special team of folks on hand. The first stage is back in your hands in a matter of hours, where it can be transported back to the assembly building using a simple crane or other specialized equipment. And it can be inserted into the processing workflow much faster than if it had been out in the ocean, and with less overhead of having to clean it, refurbish it, inspect it, etc.
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