Cloakedwand72

Do y'all think the Space-X Super heavy/Star ship would work out?

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I see another reason that the crew might be sent up separately- the in orbit refueling needed for interplanetary (and lunar?) trips. Assuming that the plan for the refueling is similar to previous versions, it might be too risky to load fuel on a crewed ship.

 

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1 hour ago, Rakaydos said:

Why does any abort capsule have to be in the nose? Stick an off-the-shalf Dragon II in each of the cargo doors, equip the doors with explosive bolts, and have 7 of the 14 initial crew sit in each one for the initial launch and reentry. Perhaps a redesigned trunk for the purpose, but otherwise, simple.

just after takeoff and final part of landing is the most dangerous, this give you attitude for parachutes to work. Crew section and cargo bay give distance to an exploding second stage. So much that you can probably reduce the power of escape system. 
Pod would still be usable space you will want seats anyway during takeoff and landing. 100 passengers is far more than you will fly with for an long time. Yes you will want some size on it for tourist flight. 

2 hours ago, Xd the great said:

I doubt the feasibility, as a 100 man LES sounds.. kerbal.

Next generation starahip: a dragon 3 mounted on a starship cargo.

cargo-BFR-and-fairing-SpaceX.jpg

This.

You would have it top mounted and cargo bay below as you can not escape the cargo hull during max-q, but yes that could work as an quick fix. need to change the heat shield so it protect the side 

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From Phil Bono's book:

P1JxXyDg.jpg

Those are for Ithacus:

ithacus4.jpg

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17 hours ago, tater said:

I'm cautiously optimistic. The fact that we could see some definitive answers via testing in the not to distant future is, well, really cool.

Agreed dude. Hope they put the hop test & re-entry test this year on Live stream for those who don't live in Texas.

1 hour ago, tater said:

From Phil Bono's book:

P1JxXyDg.jpg

Those are for Ithacus:

ithacus4.jpg

Cool that looks pretty Kerbal!

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^^^ that design is from the early 1960s, BTW.

 

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15 hours ago, sh1pman said:

Or a cluster of SuperDraco pods. Can also double as an emergency landing mode, in case of critical issues during normal landing. 

All of that extra hardware will definitely affect the crew and payload capacity, though.

Where would they land? Wouldn't the pots or something be floating like oil rig escape pods?

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There is no way they have a LES system for the entire, full Starship. It's not a thing, and won't be a thing. Dragon 2 is in the neighborhood of the payload mass fraction of the F9 stack, a little less, actually. So the LES only has to lift ~4% of the liftoff mass of the stack. Starship is way more than 4% of the liftoff mass. Any LES concept has to be a (small) subset of the Starship spacecraft. That's assuming they have any desire to do this.

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7 minutes ago, tater said:

There is no way they have a LES system for the entire, full Starship. It's not a thing, and won't be a thing. Dragon 2 is in the neighborhood of the payload mass fraction of the F9 stack, a little less, actually. So the LES only has to lift ~4% of the liftoff mass of the stack. Starship is way more than 4% of the liftoff mass. Any LES concept has to be a (small) subset of the Starship spacecraft. That's assuming they have any desire to do this.

Starship is an upper stage with integrated cargo hold and crew compartment. Pretty much like the shuttle and share many of its problems, except no solid fuel engines and its more rugged. 
Crew compartment of an starship is probably less than 4% of stack. My idea would be more like the escape pod idea for the shuttle. 
This was canceled since it would be to heavy for the shuttles limited carry capacity and it would probably not work at high supersonic speeds. 

Starship has way larger margins. It could be an issue for Moon and Mars missions. 

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9 minutes ago, magnemoe said:

Crew compartment of an starship is probably less than 4% of stack. My idea would be more like the escape pod idea for the shuttle. 

Yeah, a pod is certainly possible (even a pod that is a large chunk of the actual nose). My point is that there is no escape system that pulls the whole vehicle off, and on top of that, any LES would need to deal with a S2 (Starship) failure as a possibility, anyway.

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@tater But, uh... Absence of LES wasn't a problem for NASA during the Shuttle program. Why would it be a problem now?

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5 minutes ago, sh1pman said:

@tater But, uh... Absence of LES wasn't a problem for NASA during the Shuttle program. Why would it be a problem now?

I don't disagree (and the ejection seats were never gonna get used), but NASA is far more risk averse than they used to be.

The current images (all BFR variants so far) have shown largely crew vehicles, and some images of cargo versions. The crew versions have ridiculously huge pressurized volumes for any use short of their Mars goal (or P2P).

I don't see a business case for crew for a while, anyway, so I'd expect the cargo version first, then they wring that out, and decide how good they feel about putting people on top. That said, it seems like any first crew missions don't need (or want, given the danger) dozens of people. Seems to me a hybrid vehicle (like Shuttle) might actually make sense. A cargo variant, with crew at the nose.

The nose area, just using the conical volume before the cylinder starts has more habitable volume than Skylab, Mir, and the Shuttle---combined. So that part (or a subset) could be crew, and you could still have a large cargo bay--bigger than Shuttle's, actually.

 

I forgot to add that a subset nose, functioning as a LES pod is still frickin' huge.

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Clear answer: i have no idea ...

... but the changing of designs and construction materials actually do not rise my confidence. Especially the last material change seems strange to me. I expect them to do several years of experiments, tests, construction technique, load test, vibration stuff, weakening under stress, heat, deformation cold, warm and hot etc. blabla as it hasn't been used for such an application b4.

Anyway, first the locust. If it behaves well, we shall see a little farther. Not sure if they already think of such tedious things and peanuts as "crew safety" or "escape systems" ... what is that good for ? it is at least as safe as an airliner anyway ;-)

:wink:

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1 hour ago, sh1pman said:

@tater But, uh... Absence of LES wasn't a problem for NASA during the Shuttle program. Why would it be a problem now?

Well it obviously should have been.

i don’t see a good reason to even launch Starship with crew at all.

For big missions they will have to refuel in LEO anyway. No need to crew up until after that. The crew could be sent up on 1-2 dragons.

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Just now, Nightside said:

Well it obviously should have been.

i don’t see a good reason to even launch Starship with crew at all.

For big missions they will have to refuel in LEO anyway. No need to crew up until after that. The crew could be sent up on 1-2 dragons.

That requires them to 1) Keep F9 and Dragon programs running, employing people, launch pads, keeping lights on, etc., and 2) expend at least one S2 every time they need to send a crewed Starship somewhere. Not going to happen.

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1 hour ago, sh1pman said:

@tater But, uh... Absence of LES wasn't a problem for NASA during the Shuttle program. Why would it be a problem now?

Because the Shuttle showed just how foolish that was.

NASA at that point was overconfident. Apollo had gone through with only two major incidents, of which only one killed astronauts. They'd made that very tight deadline. On top of that, with Congress shrinking their budget, they realized they needed something cheap and affordable to make their ambitious goals such as space stations, Mars missions, etc. work. Add to that Presidential pressure to come up with something impressive on a budget, and you get a project which paid little heed to safety or economic practicality.

2 minutes ago, sh1pman said:

That requires them to 1) Keep F9 and Dragon programs running, employing people, launch pads, keeping lights on, etc., and 2) expend at least one S2 every time they need to send a crewed Starship somewhere. Not going to happen.

Then so be it. If it takes some extra cash to keep astronauts safe, then that's the price that will have to be paid. Manned BEO missions (and even LEO missions) are of very questionable utility, and not worth putting people into experimental vehicles flying at the razor-thin edge of engineering margins without a decent escape system or very thoroughly tested vehicle.

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The materials change improves my confidence, actually. Carbon fiber composite everything was by far the hardest part of what they were planning.

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I don't think an LES in the nose section would work out, due to the way the Starship's heatshield will work, right? Unless it disconnected similarly to the cargo variant of the Starship in a way (The front of the ship gets deployed). But that would mean needing a bulkhead or something in-between the nose section and the rest of the habitat area. And separate plumbing for all the life support and all.

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1 hour ago, Green Baron said:

Clear answer: i have no idea ...

... but the changing of designs and construction materials actually do not rise my confidence. Especially the last material change seems strange to me. I expect them to do several years of experiments, tests, construction technique, load test, vibration stuff, weakening under stress, heat, deformation cold, warm and hot etc. blabla as it hasn't been used for such an application b4.

Anyway, first the locust. If it behaves well, we shall see a little farther. Not sure if they already think of such tedious things and peanuts as "crew safety" or "escape systems" ... what is that good for ? it is at least as safe as an airliner anyway ;-)

:wink:

Material changes might be two build options and one won out because easier and good enough for starlink. 
Musk is playing an strategy game, he need to deploy starlink .  This unlock Mars. 
But far more important he own LEO and GEO. 

The US civil war ironclad duel left Britain with one ship of the line down from 80 something. 
With starship its one orbital operator 
Yes lots of countries will want orbital capability for national security reasons. 
But that is politic. 

 

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7 hours ago, Rakaydos said:

Why does any abort capsule have to be in the nose? Stick an off-the-shalf Dragon II in each of the cargo doors, equip the doors with explosive bolts, and have 7 of the 14 initial crew sit in each one for the initial launch and reentry. Perhaps a redesigned trunk for the purpose, but otherwise, simple.

Because it's the only truly reliable solution for a "zero-zero" eject on the launchpad - or, worse yet, when you've got an imminent hoverslam failure. You want to be going upwards upon ejection; steering post-ejection takes precious milliseconds.

3 hours ago, sh1pman said:

@tater But, uh... Absence of LES wasn't a problem for NASA during the Shuttle program. Why would it be a problem now?

I can name about fourteen reasons.

5 hours ago, tater said:

From Phil Bono's book:

 

Those are for Ithacus:

 

It's important to note that those needed LOS on the ground because they were used to guide in the actual landing.

I don't think anyone plans to land the BFR by hand as the standard mode.

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Just to point something out here.

Musk has repeatedly said that he's aiming for airliner levels of safety with BFR. Now, this is a hard thing to do, but if he can demonstrate that he has such a reliable vehicle, do we really need an escape system? If it does, then go to Boeing and Airbus and start pestering them for escape pods on all commercial airliners, because you obviously think that the risks are too high in todays aircraft. 

And no, we don't need to wait for several crashes of the BFR system to confirm that safety level. Planes have individual parts fail fairly commonly (given how many currently fly) and we can calculate from that how often a certain failure cascade will occur that results a loss-of-hull accident. The same logic can be applied to BFR when it starts flying.

Starting unmanned is entirely fair and I completely agree, but I don't think that we should wait very long before we start manned flights. 

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50 minutes ago, DDE said:

It's important to note that those needed LOS on the ground because they were used to guide in the actual landing.

I don't think anyone plans to land the BFR by hand as the standard mode.

Yeah, tech has improved rather a lot since 1963.

13 minutes ago, MinimumSky5 said:

Just to point something out here.

Musk has repeatedly said that he's aiming for airliner levels of safety with BFR. Now, this is a hard thing to do, but if he can demonstrate that he has such a reliable vehicle, do we really need an escape system? If it does, then go to Boeing and Airbus and start pestering them for escape pods on all commercial airliners, because you obviously think that the risks are too high in todays aircraft. 

And no, we don't need to wait for several crashes of the BFR system to confirm that safety level. Planes have individual parts fail fairly commonly (given how many currently fly) and we can calculate from that how often a certain failure cascade will occur that results a loss-of-hull accident. The same logic can be applied to BFR when it starts flying.

Starting unmanned is entirely fair and I completely agree, but I don't think that we should wait very long before we start manned flights. 

1 in 1.2 million LOV events is going to take a lot of uncrewed flights to demonstrate.

(that's airline level of safety)

PS--demonstrating on paper 1:270 has been non-trivial for commercial crew vehicles. Only 4 more orders of magnitude to go.

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40 minutes ago, tater said:

Yeah, tech has improved rather a lot since 1963.

1 in 1.2 million LOV events is going to take a lot of uncrewed flights to demonstrate.

(that's airline level of safety)

PS--demonstrating on paper 1:270 has been non-trivial for commercial crew vehicles. Only 4 more orders of magnitude to go.

How many different ways are there to survive engine out on the 7 sea level Starship? If they need 2 to land, but gimbal allowes it to be ANY two... Six independant engine outs is a 6th power function. Even if there was an engine out 1 out of 10 attempts, the net reliability of the engines would be exactly 1 in a million. Any more reasonable engine out number would make having enough engines for landing basically guarenteed.

Repeat this calculation for any other system with massive redundance made possible by the Starship's available mass.

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1 minute ago, Rakaydos said:

How many different ways are there to survive engine out on the 7 sea level Starship? If they need 2 to land, but gimbal allowes it to be ANY two... Six independant engine outs is a 6th power function. Even if there was an engine out 1 out of 10 attempts, the net reliability of the engines would be exactly 1 in a million. Any more reasonable engine out number would make having enough engines for landing basically guarenteed.

Repeat this calculation for any other system with massive redundance made possible by the Starship's available mass.

That's one failure mode.

What about a catastrophic RUD event? Why is 1:270 so hard for both SpaceX and Boeing to demonstrate with far simpler spacecraft that land with parachutes (very well understood tech)?

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5 minutes ago, Rakaydos said:

How many different ways are there to survive engine out on the 7 sea level Starship? If they need 2 to land, but gimbal allowes it to be ANY two... Six independant engine outs is a 6th power function. Even if there was an engine out 1 out of 10 attempts, the net reliability of the engines would be exactly 1 in a million. Any more reasonable engine out number would make having enough engines for landing basically guarenteed.

Repeat this calculation for any other system with massive redundance made possible by the Starship's available mass.

What about the flip manouvers and the meteoroid shield being the heatshield?

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21 minutes ago, Rakaydos said:

How many different ways are there to survive engine out on the 7 sea level Starship? If they need 2 to land, but gimbal allowes it to be ANY two... Six independant engine outs is a 6th power function. Even if there was an engine out 1 out of 10 attempts, the net reliability of the engines would be exactly 1 in a million. Any more reasonable engine out number would make having enough engines for landing basically guarenteed.

Repeat this calculation for any other system with massive redundance made possible by the Starship's available mass.

Independent engines-out are hardly the only failure mode imaginable.

COPV fails, and ignites the tank (which, you know, happened on a Falcon 9).

Control glitch cuts the Superheavy thrust half a second into flight.

The active cooling on the Starship reentry fails, even on a small patch, leading to burnthrough and vessel breakup on reentry.

And that's just known failure modes. Take the Columbia disaster as an example: nobody thought foamstrikes could be a failure mode until a foamstrike was a failure mode.

 

The Starship is experimental technology, in a class known to be prone to failure. It's going to be a huge amount of effort to man-rate it.

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