Apparently the engines damage themselves in the last few meters when the energy required to hover / land that gets blasted out is reflected back at the rocket by the launchpad itself.
Yes! Every kg used for legs is a kg not used for cargo... (And worse because the legs have to be carried up and down while the cargo only has to go up.)
>Surely the same energy reflection happens on launch.
Don't the launchpads have systems in place to prevent that? Eg the sound suppression system where they basically spray water into the air to absorb the sound. Does the landing pad have that?
Now that I think about it, why land upright at all? You could do a gentle controlled touchdown in a water pool and slowly tilt to horizontal with a minor splash, like the previous Starship.
I do believe it's mostly the legs, but to the first point, on launch you don't have the vacuum engine bells exposed to this. Or second stage at all, where weight matters much more, so any extra shielding you don't need is good.
If they are as precise as they are now, can't they land on asian latrine type launchpads? Like the ones the shuttle used to take off from, with the guides for the blast to go through.
That was the original concept for the booster. You need some sort of giant rocket manipulator at the launch pad no matter what. If you can make it double as an active landing target, you go from needing cm level to m level landing precision.
That's something that's been irking me whenever I watch the booster and now the ship, come crashing down at triple digit MPH speeds then watching it re-light the engines at the now front (aft end of the vehicle but going head first), what with a bunch of non-aerodynamic surfaces there. I am obviously not qualified to assess this, but I wouldn't bet on those engines being reusable more than 2, max 3 times each.
Then again, I wouldn't know how to solve this better -- if you say, have a cover protecting the engines before re-lighting, you're not shedding speed any better than without it, and after re-entry and when the speeds are relatively modest (only, say, 400mph 2-3km up vs 4000mph at 100+km) the air itself doesn't do anything to the engines anyway.
The booster has flaps that help it shed speed, but the Starship's flaps are very different, aren't they? And it's not exactly the kind of a flying brick that Space Shuttle was, either -- having it coast longer before it flips to be caught by Mechazilla, isn't a solution then...
What they do with Falcon 9 is insane as well - they have a portable heatshield for re-entry. That is, the heat shield is the exhaust of the engines. Which is absolutely glorious, not only do you brake, but you shield the rest of the ship using the exhaust as well, as a blowtorch burning to the atmosphere.
Taking an engine off and putting a replacement on is a fast process. Iirc booster gets all its engines in a day or two. Not quite like changing a lightbulb but I think it’s a fast process.
I would imagine it’s the weight savings of not having to carry thousands of pounds worth of landing legs onboard the rocket.
Don't the launchpads have systems in place to prevent that? Eg the sound suppression system where they basically spray water into the air to absorb the sound. Does the landing pad have that?
Then again, I wouldn't know how to solve this better -- if you say, have a cover protecting the engines before re-lighting, you're not shedding speed any better than without it, and after re-entry and when the speeds are relatively modest (only, say, 400mph 2-3km up vs 4000mph at 100+km) the air itself doesn't do anything to the engines anyway.
The booster has flaps that help it shed speed, but the Starship's flaps are very different, aren't they? And it's not exactly the kind of a flying brick that Space Shuttle was, either -- having it coast longer before it flips to be caught by Mechazilla, isn't a solution then...
Just ramblings of an amateur :B