SpaceX Might Try To Fly the First Starship Prototype To Successfully Land a Second Time (techcrunch.com) 65
An anonymous reader quotes a report from TechCrunch: SpaceX is fresh off a high for its Starship spacecraft development program, but according to CEO Elon Musk, it's already looking ahead to potentially repeating its latest success with an unplanned early reusability experiment. Earlier this week, SpaceX flew the SN15 (i.e. 15th prototype) of its Starship from its development site near Brownsville, Texas, and succeeded in landing it upright for the first time. Now, Musk says they could fly the same prototype a second time, a first for the Starship test and development effort.
A second test flight of SN15 is an interesting possibility among the options for the prototype. SpaceX will obviously be conducting a number of other check-outs and gathering as much data as it can from the vehicle, in addition to whatever it collected from onboard sensors, but the options for the craft after that basically amounted to stress testing it to failure, or dismantling it and studying the pieces. A second flight attempt is an interesting additional option that could provide SpaceX with a lot of invaluable data about its planned re-use of the production version of Starship.
A second test flight of SN15 is an interesting possibility among the options for the prototype. SpaceX will obviously be conducting a number of other check-outs and gathering as much data as it can from the vehicle, in addition to whatever it collected from onboard sensors, but the options for the craft after that basically amounted to stress testing it to failure, or dismantling it and studying the pieces. A second flight attempt is an interesting additional option that could provide SpaceX with a lot of invaluable data about its planned re-use of the production version of Starship.
Iterate fast, break things (Score:5, Interesting)
To some extent, SpaceX's method and approach to things is very close to the very early days of rocketry. The V-2 had hundreds of test launches https://en.wikipedia.org/wiki/List_of_V-2_test_launches [wikipedia.org]. And it seems that without too much exaggeration one can say that there's a definite possibility that the Starship system will be as big a deal in the long-term as the V2 in terms of fundamentally changing our relationship to space. Trying to launch SN-15 again would be completely in keeping with the sort of iterated approach of those early days of rocketry.
But there's another aspect of what SpaceX that doesn't necessarily get noticed as much or isn't as obvious. For a long time, the thought process for making rockets better was to make them have higher performing fuels. Thus, you had a lot of focus on hydrogen as a fuel, and you ended up with things like the RS-25, the space shuttle main engines, which were hydrolox engines with some of the most impressive engineering ever especially given their reusability. https://en.wikipedia.org/wiki/RS-25 [wikipedia.org]. But people have tried also make more exotic fuel choices, like using liquid fluorine as an oxidizer, or even ClF3 https://en.wikipedia.org/wiki/Chlorine_trifluoride#Rocket_propellant [wikipedia.org]. And although one of Musk's favorite books is Clark's "Ignition!: An Informal History of Liquid Rocket Propellants" (which I strongly recommend), which focuses a lot on these more exotic propellants, SpaceX has consistently chosen relatively simple and well-understood propellants. Their Merlin engine uses kerosene. And the Raptors, the engines for Starship, use methane, which is a relatively new choice of fuel, but is well-behaved and turns out to be a very good fuel from a reuse standpoint. For that reason a whole bunch of other companies, including Blue Origin and some Chinese and Russian groups are also moving to methane. But even as they aren't using any sort of exotic fuel, SpaceX has made the Raptor an incredibly high performance engine, in part due it being the first successful full flow stage combustion engine. https://en.wikipedia.org/wiki/Staged_combustion_cycle#Full-flow_staged_combustion_cycle [wikipedia.org]. So the design philosophy seems in part to be to use a not too temperamental propellant mixture, and then optimize it as much as possible.
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"without too much exaggeration one can say that there's a definite possibility that the Starship system will be as big a deal in the long-term as the V2"
Not too much exaggeration.
"hydrolox engines with some of the most impressive engineering ever"
Too much exaggeration.
Great comment anyway.
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His ultimate goal is to put humans on Mars, a lot of them.
And while some people might think it's idle boasting or some marketing ploy, I do believe that's what's driving Elon's decisions in the direction SpaceX is taking.
And since SpaceX is going to fund this mainly out of their own pocket (Except for when their goals align with NASA and such) their incentive structure is fundamentally different from the aerospace contractors who've been operating in this field for decades.
So the main technical measure of s
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Musk is an optimist when it comes to technological development - and AI research has been eating such optimists for breakfast since long before Musk was born.
In pretty much every other field, if Musk says he'll do something, I take his word for it. I may double (or more) his estimate for how long it will take, but I assume he'll get there eventually.
AI though - we're trying to create some fragment of an artificial mind, and every step forward has consistently proven to be far more difficult and less useful
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SpaceX's choice of fuel for Starship came down to one simple question - what kind of fuel can actually be produced using only resources found on Mars? All you need to make methane is carbon dioxide, water, and a lot of energy.
Re:Iterate fast, break things (Score:4, Informative)
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The temperature range was important too. Methane and oxygen are both liquid at the same temperature range, especially when super-cooled for higher fuel density. Hydrogen needs such a low temperature to liquefy that oxygen has to be insulated from it to keep from freezing. With methalox, only a simple spherical metal tank cap is needed between the two tanks. Oxygen ice is not a good thing to have around. In addition to clogging pipes, it likes to get explode-y around carbon fiber.
LH2 is also a pain in the a
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Assuming we'll go with silly chemical rockets. With other types of rockets we could leave from Earth orbit, land on Mars and go back to orbiting Earth without refuel, using the chemical rockets only to and from orbit.
Chemical rockets are so 20th century, they aren't the way forward to Mars and beyond.
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Unfortunately there are no rocket engines that realistically have the potential to do such a thing within out lifetimes.
Ion drives have enormous interplanetary potential, but require enormous amounts of power to provide small but sustained accelerations. Great for transporting large amounts of cargo around the solar system if you're patient, or have a gargantuan nuclear reactor strapped to your ship. Not so great for making quick hops between planets to avoid health problems - at least not until we develo
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We have the technology to build a few types of nuclear rocket that could do what I described, it not any magic pie in the sky that depends on new materials or new breakthroughs.
Realistically, we're wasting our time with chemical rockets.
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Ah - I misread. I thought you said leave *Earth*, rather than Earth orbit. Which reasonably requires an engine that can safely suffer a catastrophic engine failure without spreading radioactive fallout all over the place. You're absolutely right, from orbit outward, nuclear makes wonderful sense... at least until we develop high-power ion drives. And even then, nuclear is likely to be a much cheaper option for crazy-high thrust scenarios like retrieving mountains of platinum from the Belt or pushing lar
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Mars winds do have prevailing direction though. That can be part of minimizing risk of contamination from crash of nuclear rocket.
Our hypothetical colony could put its launch port "far" from the cave or hole where they live though, and drive to it. Launch and send rocket in direction further away. We''re already doing this with payloads of nuclear material, launching from Cape Canaveral over the ocean. Curiosity rover for example has five kg of pu oxide in it.
I'll say the mean and cruel thing that space
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> Crashing of nuclear rocket is part of the risk they'll have to accept along with list of dozens of other things that could kill them
No, it's one they may *choose* to face. They may also choose to ban nuclear rockets anywhere near inhabited areas and require chemical or ion drives within those nuclear exclusion zones, just as at least "dirty" nuclear rockets would likely be banned from operating on Earth. (Orion drives being the obvious extreme example - flying one of those over any nation on Earth wo
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No, you watched too many sci-fi shows imagining colony would have some kind of separate power.
The colonists will have no voice whatsoever in what type of craft they will ride. They will not have the power to ban any rocket type. They are subjects of their Earth dwelling government and will do whatever that government says.
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For a while. How long did colonial power last over the Americas?
You're also assuming that the Earth-based governments (or more likely, corporations) would want to jeopardize their investments, rather than just making the colonies produce enough chemical propellant to handle travel between surface and orbit
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Ha! Colonial power over Americas lasted centuries. Will last longer over Mars.
No significant risk with nuclear rockets on Mars for reasons and with practices I gave, why waste resources making puny weak chemical rockets? We have the same risks with certain launches on earth anyway, to say nothing of the immense nuclear stockpiles. We're more likely to contaminate large area of Earth with fallout than have accident on Mars that would harm anyone other than those who crashed.
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Perhaps.
The Americas were also very profitable, and only a cheap boat ride away.
So far as we've been able to tell, Mars has absolutely nothing of economic value to offer Earth. That's likely to be a major problem in any large-scale colonization plans.
Personally, I suspect colonization of Mars will mostly fizzle until the asteroid belt is thriving and Belters want someplace relatively pleasant and open to vacation or retire that won't leave them miserable or dead like returning to Earth gravity probably wou
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A traditional space elevator has a lot more problems than just the materials required for it. The big problem, to my mind, is that an actual elevator is too slow, crawling to geosynchronous orbit. Part of that slow trip is also through a very bad neighborhood. That is with the elevator pictured as a fixed velocity trip into orbit. Technically it's more complicated than that, since it's only constant velocity in a reference frame fixed on the cable itself. That cable is rotating with the earth though, so the
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I'm a big fan of pinwheels myself - they can be made relatively tiny (dozens to hundreds of miles instead of (tens of) thousands like launch loops, beanstalks, etc), with existing materials, and no primary moving parts. Then you just have to get outside the atmosphere at the right place and time to grab the lower end as it "rolls" past and let it do the other 95% of the work to get you into orbit.
With careful timing you could even use them to get out of orbit as well, in which case you transfer your orbita
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I'm a big fan of pinwheels myself - they can be made relatively tiny (dozens to hundreds of miles instead of (tens of) thousands like launch loops, beanstalks, etc), with existing materials, and no primary moving parts. Then you just have to get outside the atmosphere at the right place and time to grab the lower end as it "rolls" past and let it do the other 95% of the work to get you into orbit.
With careful timing you could even use them to get out of orbit as well, in which case you transfer your orbital momentum to the pinwheel with 100% efficiency, and it can then be transferred to the next payload being launched. Essentially letting you move payloads between orbit and high-altitude without consuming any energy, so long as the mass flow is the same in both directions.
Pinwheels/skyhooks are another neat idea. Apparently you need massive stations in orbit for it and there are some questions about how the tethers will behave. All of these iideas are speculative of course, until someone actually builds them.
Beanstalks are an intruiging idea - though I'd say being physically impossible to build on Earth is pretty much the biggest problem you can have. Time and radiation are easy to deal with in comparison. I'm pretty sure "unlimited" acceleration such as you suggest wouldn't be feasible - you'll be fighting gravity the whole way, and there's a limit to how much thrust you can realistically generate along the beanstalk. A limit that will tend to decrease as your speed increases. Certainly once outside the atmosphere I'd expect it to accelerate to the top speed it could sustain, but substantial radiation shielding is likely to also be important since the trip could easily take days. And sure, at some point before you reach geostationary you could indeed let go and remain in orbit - you could do that even if you came to a complete stop first - geostationary orbit has a LOT more angular momentum than needed to stay above LEO, even a modest fraction will keep you in orbit. You'll still be using the whole cable though - just like you still use the whole rope in gym class even if you only climb half way to the ceiling. The top half of the rope is what keeps the bottom half in the air.
Certainly the physical impossibility is a problem. Although, apparently it's actually entirely possible with normal materials with a tapered cable, it's just that the tether would have to be miles thick by the time it gets to the base station. So not actually impossible,
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>Pinwheels/skyhooks are another neat idea. Apparently you need massive stations in orbit for it
Not really - you need a pretty long tether, with enough mass at either end so that the mass of the ships won't drastically unbalance it. It's true we wouldn't know for sure how the tether would behave in orbit, but the analyses I've seen all suggest that the gravitational gradient shouldn't be a problem as long as it's spinning fast enough - and just to do its job it's going to have to spin fast enough for "ce
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Not really - you need a pretty long tether, with enough mass at either end so that the mass of the ships won't drastically unbalance it. It's true we wouldn't know for sure how the tether would behave in orbit, but the analyses I've seen all suggest that the gravitational gradient shouldn't be a problem as long as it's spinning fast enough - and just to do its job it's going to have to spin fast enough for "centrifugal force" to greatly exceed gravity at the endpoints.
I think from what I've read, the variant where the hook would appear to descend pretty much straight down and then go up again would need a pretty massive station and the variants with a smaller station would require mid-air interception by a hypersonic vehicle which could be pretty tricky. I'm all for a big station of course, so I say build the variant where the "hook" just appears to come down and go straight up again. As for the thrust required for station keeping, it's pretty cheap when you can just se
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>I think from what I've read, the variant where the hook would appear to descend pretty much straight down and then go up again would need a pretty massive station and the variants with a smaller station would require mid-air interception by a hypersonic vehicle which could be pretty tricky.
None really need a station, it's the length of the "rope" that's the issue. By the "coming straight down" variety, I assume you mean the kind that "roll" across the Earth so that the bottom end matches speed with the
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None really need a station, it's the length of the "rope" that's the issue. By the "coming straight down" variety, I assume you mean the kind that "roll" across the Earth so that the bottom end matches speed with the ground, like a point on the edge of a wheel approaches almost perfect vertical motion as it approaches the ground?
To get that you have to deliver 100% of orbital velocity, so that would be the "144x the mass" version at the end - so 1152 km long at 3g max acceleration, or, 691km for the 5g version. Kind of huge - but only in one direction, and like I said, all that length would mass less than the empire state building (well, except that in reality you'd to make the middle a lot thicker to support it's own mass, just as with a beanstalk - though not nearly so much so since it's far shorter.)
And yeah, anything smaller you need to deliver the first N% - a hypesonic plane might be capable of that if the skyhook were long enough.
The moon actually has some really interesting skyhook potential - it'd need continuous stabilization since lunar orbits are inherently unstable, but if I remember my calculations correctly from many years ago a ground-speed matching version, potentially capable of extending a tether to snag payloads directly from the surface, could be only a few hundred km long, and would capable of launching payloads on transfer orbits to Mars or Venus, while subjecting them to only relatively modest acceleration
Out of the various plans, that seems like one that's feasible. You have to get a lot to orbit, but after that the payback is immense, you just need to have an economy where the payback in easy access to space is worth it. Of course, while it's not a "megastructure" per se, there's definitely increased difficulty because it's in space because of all the required launches. In some cases, an Earth-bound megastructure might be easier. For example an aerostat/hybrid structure that raises a linear accelerator up
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Not sure what the mass would be for the moon one - but the acceleration would be a lot lower than for Earth, and the length a lot shorter, so it should be a small fraction of the mass of the Earth one. Really wish I could find my old calculations.
I think the big issue is that to build any such structure, you need the traffic flow to justify it, and that just doesn't exist right now. You don't build highways to places nobody travels. Certainly not around the moon, where it would be relatively small, but t
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Oh, and you have me intrigued with the counter-rotating ring idea, any chance you could use your greater knowledge to point me at some information on it? My Google-fu isn't turning up anything remotely relevant.
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Not sure what the mass would be for the moon one - but the acceleration would be a lot lower than for Earth, and the length a lot shorter, so it should be a small fraction of the mass of the Earth one. Really wish I could find my old calculations.
I think the big issue is that to build any such structure, you need the traffic flow to justify it, and that just doesn't exist right now. You don't build highways to places nobody travels. Certainly not around the moon, where it would be relatively small, but the orbital dynamics challenges will be far greater. And of course the moon version is also grossly overpowered for just getting into orbit, you'd have to release from the tether before you got more than a fraction of the way up or be launched out of Earth space entirely. And linear accelerators on the surface are likely to be far more convenient
You do build highways where nobody travels if the Olympics are going to be there. So Moonlympics for the win. You also do it if it provides pork to a bunch of Senators districts, but SLS already has that. It is a tricky bootstrapping issue. The demand for more space travel will probably come as we do more space travel, but right now we would need a program demanding a high number of guaranteed launches for anyone to look at anything like this seriously.
If they're magical enough I suppose - but I'm pretty sure carbon nanotubes would still need to be ...thousands? ...millions? of times the cross-sectional area at the middle as at the surface to support its own weight. And carbon-carbon bonds offer the greatest strength-to-weight ratio we have any reason to believe is physically possible with atoms. Different geometries like carbon nanothreads may increase increase the ratio a bit, but we probably aren't going to ever see even a single order of magnitude improvement over the strength of nanotubes, even if we spend billions of years working on it. Pretty disappointing in some ways, though it's also rather impressive to think that we've developed materials so close to the theoretically highest strength-to-weight ratio possible so early in our technological development.
Though... I suppose "neutronium" based materials might eventually have potential, assuming it's actually stable and possible to produce in anything other than a gravity-bonded neutron star. The bond energy between neutrons is on the order of a few million times stronger than that between carbon atoms, while a single-file chain of neutrons the length of a carbon bond would "only" be about 7,000x more massive than a carbon atom. So you could be looking at a thousand-fold increase in strength-to-weight ratio.... assuming mechanical strength is linearly proportional to bond energy.
Probably couldn't make it from just neutrons and have i
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Let's hear it for the Moonlympics! Earthers have gotten complacent, barely improving at all from year to year - it's time to start raising the bar on new record-setters tenfold at least!
But seriously, that's the real chicken-and-egg problem - we need a (profit-generating) reason to get up there en masse before it makes sense to make the huge infrastructure investment to be able to do so cheaply. And we need to be able to do so cheaply before there will be compelling reasons to do so en masse. We're start
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I suspect not - nuclear energy comes from the change in per-nucleon binding energy based on nucleus size. Which climbs very rapidly (if erratically) from hydrogen to oxygen (hence fusion being far more energy-dense than fission), then more slowly until it peaks at iron, and then very slowly declines as nuclei get more massive - basically, moving toward iron increases the per-nucleon binding energy, and thus releases energy in the process. Graph: https://cdn.britannica.com/46/... [britannica.com]
But assuming that downward trend continues (and I don't think there's any reason to doubt that) then the energy is going to have to (possibly asymptotically) approach some minimum constant value as the "nucleus" size continues to increase. Which I suspect would happen long before you reached the ballpark of 300 billion neutrons needed to fill the volume of a single carbon atom.
And once the energy-per-nucleon remains constant if you cut the thing in half, no energy would be released by doing so.
What would worry me though, is what happens when normal matter contacts neutronium? It probably wouldn't be explosive, but electron repulsion wouldn't keep neutronium at bay, and the gravitational pull of such a dense object at subatomic distances is going to be intense. Not black-hole intense, but probably far stronger than the electromagnetic forces holding chemical bonds together, so I suspect it would drag in all nearby atoms, consolidating them into more neutronium, while the atomic bonds would drag more atoms into range before the conversion happened. Poke an invisibly small piece of neutronium, and I suspect it would embed within your finger and proceed to rapidly drag your entire body down to its surface. Drop it into a planet or star... and I imagine the results would not be pretty. Maybe not a substance you'd actually want to bring anywhere near any inhabited plant. Or star system for that matter. Who needs sci-fi physics superweapons when all you have to do is launch a fleck of neutronium at your target and watch it implode?
I suppose that it's pretty hard to predict the behavior of such a speculative form of matter. I do know that there would be a huge amount of energy bound up in those strands, and you would have created a way that nuclear fission could be performed through mundane physical means. Even one strand might be tremendously strong, but you could still find some mechanical arrangement that could snap it. Now, maybe only a small amount of energy is released at the site of the break and it does not create a chain reac
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Hey, making neutronium is easy. The hard part is figuring out how to get it back off the surface of the neutron star :-D
But yeah, I'm pretty sure there's still a lot of speculative physics involved in the mechanical properties of nucleons. We're still at the making and breaking mud pies stage of nuclear physics. QM might theoretically be able to predict the behavior (assuming the current approximation is accurate enough), but I suspect that just as with chemistry, the calculations rapidly become so compl
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To some extent, SpaceX's method and approach to things is very close to the very early days of rocketry. The V-2 had hundreds of test launches
Big difference between the two programs, though! SpaceX has to pay its Jewish workers.
Re: Iterate fast, break things (Score:2)
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in part due it being the first successful full flow stage combustion engine
Are they running Raptors at the intended combustion chamber pressures yet? They were using lower pressures initially, IDK how far along the ramp-up they are.
Relaunch Until it Explodes (Score:5, Funny)
They need to keep launching it until it explodes. Otherwise they'll have to figure out what to do with the rocket.
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Send it to chase after the roadster
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Otherwise they'll have to figure out what to do with the rocket.
What, you've never seen those guys driving around with old Chevy pickups, with plywood side walls, full of rusty bikes and bed frames?
It's steel. You scrap it.
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Well, you can still scrap it after a unplanned rapid disassembly.
As long as it hits the ground instead of the water.
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They haven't had any qualms about scrapping all the others.
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They could always start a grain-silo delivery business - same-day shipping to anywhere on Earth!
(Standard suborbital shipping charges may apply.)
Mars 2026 (Score:3)
The first human colony on Mars will be seeded by Elon Musk himself who will land there aboard a SpaceX Starship together with a handpicked crew of seven men and sixteen women sometime in 2026.
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Re: Suspiciously Specific (Score:2)
16 female and seven men is a time-tested formula for seeding a new underground human colony. This is the number of men and women Neo was going to take to seed a new underground city of Zion in Matrix Reloaded.
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Why isn't this more about Elon Musk? I love hearing about how smart and independent he is. Bitdoggiecoin to the moon!
I submitted the story about the successful SN15 test earlier this week, but because I mentioned Musk, it didn't get voted up, although it is actually linked above.
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Try for lower landing (Score:2)
Obvious difference with this attempt versus the earlier ones is you can see they started their flip maneuver much higher up, it wasn't even out of the cloud cover yet when it was vertical. I imagine the best data out of a repeat would be 1) Do the engines still perform and 2) Put the flip lower and test again.
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Those were extremely low clouds / high fog. It flipped at the same time as the others, which is about 500 meters.
The planned change to the maneuver was to light all three engines, but they only ended up lighting two (probably one engine has an issue).
Someday (Score:1)
Someday Starship will be able to leave Earth's atmosphere and LEO and travel to other bodies in the Solar System. We could even travel and possibly land on the Moon, or beyond (Mars?). This was previously unimaginable. That will be a great day for humanity, and it was all accomplished by a single man. A great man! A man who had the vision to create a rocket against unimaginable odds. And the SAME great man invented electric cars, autonomous driving, hyperloops, satellite internet and solar power. People sai
Re: Someday (Score:2)
Why Wouldn't They, It Makes Sense (Score:5, Insightful)
SNL (Score:3)
Give the launch order from the set of SNL. Success or fail, that'd be a Woodstock level happening.
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I... like this idea.
That's some grade-A publicity stunt. Hilarious if it crashes with him live on stage, super cool if it does it again and lands.
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Might. (Score:2)
Might. Wake me when they do.