161–170 of 207 posts
"Unfortunately, this video is not available in Germany because it may contain music for which GEMA has not granted the respective music rights." Here's a short link to bypass: http://www.ssyoutube.com/watch?v=sWFFiubtC3c
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?
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Could and real or kerbal rocket scientists here explain why SpaceX isn't doing something like the curiosity rover landing? Sure there's 3 extra steps, deploy parachute, cut parachute, and evasive maneuver, but the fuel saving would massive.
I'm not sure the savings would be as massive as you think (and would be offset by other costs). Parachutes (and associated equipment) are heavy, so you'll burn fuel lifting that extra weight. Parachutes are complicated, and would be an extra system to develop, test, and validate. Parachutes are annoying to repack/replace (increasing turnaround time). Parachutes put odd stresses on large objects when they deploy (incr…
That's the TLDR. The delta-vee from the parachute is not worth the trouble.
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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?
I imagine there's a lot less fuel required to land than is required to take off. That is, on launch, the rocket is probably (eventually) reaching speeds of several thousand miles per hour. Upon landing, the atmosphere does most of the slowing-down for you, so you only need enough fuel to reduce the speed from terminal velocity (not sure what this would be for a rocket, probably several hundred miles an hour, at least…
Right.
At take off, the delta vee is the escape velocity PLUS all the losses due to friction, which are tremendous.
At landing, the delta vee is only equal to terminal velocity. EDIT: Okay, plus some flying time on top of the landing point.
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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.
Actually not true, but I suspect if you've been researching this you've discovered that. NASA has of course researched vertical landing techniques from the beginning, both with manned missions (Apollo) and robotic. However, it was "on the list" prior to the great de-funding and generally sat in the 'to be looked at' drawer from then on. The DC-X program, and others like it were spawned by private industry who were be…
And the 1970s one weighed a lot more than 3.52 oz!
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…
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I don't understand the need for the intermediary stages, couldn't the main rocket just deliver the payload and then land? As it is in that video, it's having to carry engines and fuel for 3 separate stages, for no apparent reason.
It would be more convenient and cost effective to do so, if we could. But we lack the technology. The rocket equation is a harsh mistress, it demands exponential amounts of fuel the faster you want to accelerate a given stage (specifically, as a ratio to the exhaust velocity of the rocket). Given that orbital velocity is quite high (about 8.5 km/s) relative to the exhaust velocity of the best chemical propellants (ab…
Nuclear rockets would be so awesome if they weren't so nasty.
I can't even begin to describe how psyched I get when I see demos like this. The advances that SpaceX and their competitors are making in terms of making access to space cheaper are what will eventually lead to the human species settling on other planets. It also reminds me that when it comes to science, and who knows, maybe other things as well, it's not just public sector vs private sector. SpaceX wouldn't be drivi…
First, you need a massive government program to get the technology from the pie in the sky stage to something usable - a multi-decade, arduous process that produces no short-term profits, if any. Once that's done, it's time for the private sector to step in.
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Actually not true, but I suspect if you've been researching this you've discovered that. NASA has of course researched vertical landing techniques from the beginning, both with manned missions (Apollo) and robotic. However, it was "on the list" prior to the great de-funding and generally sat in the 'to be looked at' drawer from then on. The DC-X program, and others like it were spawned by private industry who were be…
>A six degree of freedom inertial unit was $125,000 in 1970 and resolved differences of .1G. A 9 degree of freedom unit from Sparkfun Electronics [1] is now $125, and reliably resolves 1/4096'th of a G. And the 1970s one weighed a lot more than 3.52 oz! http://i.imgur.com/nrm2fUb.jpg
