It's a real shame they had nothing in the indian ocean waiting to film the upper stage. I mean cmon, people build solar drone boats as college projects for relative pennies, don't tell me spacex couldn't have one autonomously sail to the projected point and launch a drone to record what happens if it makes it that far.
I think the upper stage missed by something like 6 km from its intended target (which is not surprising given the toasty state of the fins) - even with drones you couldn't really bracket a large enough area to get good camera footage.
Basically it definitely wouldn't be worth the expense for the benefit - I think they'd prefer just to film the one which nails it.
I’d bet that Starship will have a continuously updated, estimated landing point throughout the whole maneuver anyways. A plane can easily go 6km in about a minute (at a mere 360km/h), so if there was a plane trying to film the descent and landing, it will have some kind of footage.
Is it going to make too little sense to add angled subscale engines in the interstage area in quadcopter configuration, in a manner that resembles Porsche 918? That'll look cool, and could mitigate propellant feed problem too.
Probably as much sense as if you're building some software and have the general design worked out and are still working on some broken bits, then someone comes along and suggests why don't you use this separate library to patch over the broken bits instead of fixing them like you were already doing?
I think you just invented ullage rockets (if you meant that the thrust of these small rockets should help to settle the fuel at the bottom of the tanks).
I mean, firing all the way down. Ullage motors are for ignitions only, my proposal is dedicated descent engines. It'll improve control authority by a lot too.
It's inefficient: the rocket engines they have have a specific impulse which they get for their design and size. Generally smaller rocket engines have worse Isp. In both cases the issue is that (1) you need the engine to light up and (2) you need it to last through the entire burn. And all of this would be more weight and complexity.
The other problem is fuel: while the stage would be getting lighter burning fuel the whole way down, it's also slowing down so you spend more time in the descent stage, which in turn is increasing your engine durability and cooling requirements and increasing your fuel use etc.
And after all that, you're either (1) coming to zero velocity on the descent engines alone or (2) still need the Raptors to relight so you can actually land.
In the case of (1) you're hefting around a bunch of engines you're not using most of the flight, and expending more fuel etc. on the take off and landing. In the case of (2) well, why not just get the Raptors to be super-reliable and do the braking burn as-is?
As it is, we've now seen the Superheavy can do a landing burn with an engine failure to boot - improving from there takes us from those initial Falcon 9 landings to where are today (so common it's not news).
Yeah so like, a pair of "Merlin Methalox" on sides. Flying machines need at least four independent degrees of freedom to fly, but not less, so authority wise two XY gimbaling Merlins should do.
The current Raptor setup seems to be working pretty well for boostback and entry burns while the vehicle is in total vacuum, but it seem to get sketchier as propellants are expended and TWR increases, while altitude coincidentally reduces and aerodynamic stress increases. Almost every materials are stronger against tensile stresses than compressive stresses, and stainless steel is no exception, so an array of mighty Raptors trying to compress the booster lengthwise from the bottom, could be, just could be, less ideal than a pair of tip-jets pulling upwards and straightening the shell.
As for them being dead weight on ascent, I don't know, but as I understand it, every bit of thrust buys a bit of payloads at very moment of launch, then thrust requirement rapidly decreases and effect of Isp becomes more dominant. So I think there could be potentially some net positive effect in "test firing" the proposed side-jets at launch for few moments, depending on various parameters. I'm way too much of a layperson on actual rocketry to be even remotely sure, though.
I mean, picture Superheavy coming in to launch site, then the side facing retro-rockets light up as high as 100m above the ground, suspending the booster under it and sliding it gently onto the chopsticks. The retro-rockets are slightly angled, like Dragon 2 thrusters or slightly more angled. Isn't that going to look even cooler than what it is already?
> Almost every materials are stronger against tensile stresses than compressive stresses, and stainless steel is no exception, so an array of mighty Raptors trying to compress the booster lengthwise from the bottom, could be, just could be, less ideal than a pair of tip-jets pulling upwards and straightening the shell.
Maybe it's less ideal, but SpaceX has almost certainly run the simulations to figure out whether the booster can indeed survive a late-stage launch configuration, and they probably found that the current design is perfectly capable of withstanding the stresses.
> So I think there could be potentially some net positive effect in "test firing" the proposed side-jets at launch for few moments
Only if you fired them most of the way up. If you only fire them for a few seconds, they're still dead weight for 90%+ of the booster flight, and the extra thrust wouldn't be enough to compensate.
> Isn't that going to look even cooler than what it is already?
Rocket design is not about looking cool, it's about shaving off as much weight as you can and adding as much thrust as you can. Cool looks are generally an afterthought (in fact, by going for an unpainted stainless steel, SpaceX is saving a lot of weight that would be added if they had to paint the entire thing).
SpaceX isn't building to cover ideal microoptimizations in certain parts of flight, they're building the best overall configuration that will work in the specific launch profile that they are targeting.
But there's flame coming from lower rocket body in the video, that suggests partial RUD around thrust structure, which has to be looked into and worked a lot.
There's already fuel line going into the fins as a ghetto hydraulics, so it should be more of "just" adding the oxidizer line rather than completely redoing that area for something that hasn't been done. Plus it could make the entire stack more flush and sleek.
The engines combust fuel to run their turbopumps, the exhaust will be the flames coming from the side of the rocket body. You can see it on the ascent as well. On Falcon 9 too.
Raptor is a full flow staged combustion engine [0], that means that the preburner exhaust is fed into the main combustion chamber. This is more efficient than dumping it separately like it happens on the Falcon 9 engines [1]. The black, sooty smoke on the first image of the Wikipedia article [1] is the (kerosene) fuel-rich preburner exhaust of the Merlin engine.
This _looks_ incredible fake. I’m not saying that it is fake but it _looks_ like out its out of a b-movie remake. I guess this is the SpaceX/Elon style.
