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I wonder why these human inventions seemed to have happened in reverse order? Normally, you'd expect someone to land a small or medium sized prototype rocket b

by nayuki 2y ago

I wonder why these human inventions seemed to have happened in reverse order? Normally, you'd expect someone to land a small or medium sized prototype rocket before the big real thing. Instead, SpaceX solved the vertical rocket landing problem for a full-size rocket at incredible cost and difficulty, and now a hobbyist copies the idea and scales it down. I might be missing something here. Maybe someone solved the problem of vertical landing for less-than-full-size rockets before SpaceX? Maybe there's no value in solving that problem, so SpaceX jumped to full size right away?

bobthepanda 2y ago
eh, some things get harder as you miniaturize. computers used to be the size of rooms. i would imagine that for the (profitable) problem space the value is in heavier payloads, so that's what makes sense to target first. and FWIW the SpaceX rockets have gotten bigger over time: https://www.teslarati.com/wp-content/uploads/2019/08/F9-FH-BFR-to-scale-SpaceX-18m-Starship-2019.jpg https://www.teslarati.com/wp-content/uploads/2019/08/F9-FH-B...
dotnet00 2y ago
As others have mentioned, there have been several rockets of various sizes that have done vertical landing. What SpaceX solved was the requirements to do it economically while keeping the booster cheap enough to both initially build and then later refurbish for reflight. Even when not reused, a Falcon 9 is cheaper than the rockets of its generation. SpaceX also did self-landing tests with a grasshopper vehicle prior to working on F9 landings. On top of that, this kind of hobby rocketry is very divorced from 'real' rocketry in most ways. The closest analogue to this kind of propulsive landing approach would probably be how Soyuz uses some small rockets that fire right before the capsule touches down to soften the impact, or similarly with New Shepard but instead using cold gas thrusters. Doing it at this scale is really not that applicable to doing it well in terms of reusing a rocket stage at an orbital rocketry scale. Most of the challenges of landing that are in all the things a model rocket typically does not have. Not to discount the work though, the problem solving experience is certainly transferable.
shagie 2y ago
Model rockets work with solid rocket motors which have a very different (and once you light them uncontrollable) performance than liquid rocket motors where you can throttle them. > and now a hobbyist copies the idea and scales it down. The rocket is still working with solid rocket motors. This isn't scaled down - it is an entirely different technology based on precalculated motor performance and altitude sensors. If you could get the space shuttle solid rocket boosters to land, that would be comparable.
Gravityloss 2y ago
DC-X, a Japanese lander and all the Lunar Lander Challenge participants did it on a smaller scale, repeatedly and some even routinely beforehand.
Etheryte 2y ago
SpaceX was hardly the first to solve VTVL, there's a sizeable list of successes before them [0]. [0] https://en.m.wikipedia.org/wiki/VTVL https://en.m.wikipedia.org/wiki/VTVL

by nayuki 2y ago

bobthepanda 2y ago

eh, some things get harder as you miniaturize. computers used to be the size of rooms. i would imagine that for the (profitable) problem space the value is in heavier payloads, so that's what makes sense to target first. and FWIW the SpaceX rockets have gotten bigger over time: https://www.teslarati.com/wp-content/uploads/2019/08/F9-FH-BFR-to-scale-SpaceX-18m-Starship-2019.jpg https://www.teslarati.com/wp-content/uploads/2019/08/F9-FH-B...

dotnet00 2y ago

As others have mentioned, there have been several rockets of various sizes that have done vertical landing. What SpaceX solved was the requirements to do it economically while keeping the booster cheap enough to both initially build and then later refurbish for reflight. Even when not reused, a Falcon 9 is cheaper than the rockets of its generation. SpaceX also did self-landing tests with a grasshopper vehicle prior to working on F9 landings. On top of that, this kind of hobby rocketry is very divorced from 'real' rocketry in most ways. The closest analogue to this kind of propulsive landing approach would probably be how Soyuz uses some small rockets that fire right before the capsule touches down to soften the impact, or similarly with New Shepard but instead using cold gas thrusters. Doing it at this scale is really not that applicable to doing it well in terms of reusing a rocket stage at an orbital rocketry scale. Most of the challenges of landing that are in all the things a model rocket typically does not have. Not to discount the work though, the problem solving experience is certainly transferable.

shagie 2y ago

Model rockets work with solid rocket motors which have a very different (and once you light them uncontrollable) performance than liquid rocket motors where you can throttle them. > and now a hobbyist copies the idea and scales it down. The rocket is still working with solid rocket motors. This isn't scaled down - it is an entirely different technology based on precalculated motor performance and altitude sensors. If you could get the space shuttle solid rocket boosters to land, that would be comparable.

Gravityloss 2y ago

DC-X, a Japanese lander and all the Lunar Lander Challenge participants did it on a smaller scale, repeatedly and some even routinely beforehand.

Etheryte 2y ago

SpaceX was hardly the first to solve VTVL, there's a sizeable list of successes before them [0]. [0] https://en.m.wikipedia.org/wiki/VTVL https://en.m.wikipedia.org/wiki/VTVL