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

[DDE]

22 minutes ago, tater said:

I'm unsure how safe you can get rocket engines and their associated tanks and plumbing. Is there an upper limit?

Probably. There’s simply much more energy involved, and that’s probably a source of risk that can never be entirely mitigated.

Plus, the Tyrrany of the Rocket Equation punishes anyone seeking to include safety margins.

[Terwin]

3 hours ago, Xd the great said:

What happens if starlink fails?

Are you asking about SpaceX being unable to get the satellites into orbit, or at least not enough to satisfy the FCC?  I expect lots of legal wrangling to get an extension if it is not in time, and considering the SpaceX launch history, I think the 'not at all' option is rather improbable.

 

If you are talking about the business side, you must consider: how valuable is it to be able to buy a box from Amazon that will provide reliable high-speed broad-band anywhere outside of the arctic?

At $50/month you under-cut probably more than half of the terrestrial ISPs in the US, and provide sea-based service which is a fraction of the current costs and probably at least one order of magnitude faster.  This is not even getting into the areas where  there is limited/missing/damaged infrastructure and there is no other option available than satellite internet and Starlink will be the fastest(due to low altitude satellites).  Then there is the mobile market(Smart cars, RVs, Busses, Fire departments, Emergency rescue, etc).

Any company that can't make a profit filling those needs should fire their accounting and sales departments.

[tater]

1 hour ago, DDE said:

Plus, the Tyrrany of the Rocket Equation punishes anyone seeking to include safety margins.

This is where "bigger is better" comes in. The downside of course is that economies of scale (payload mass fraction remains basically constant, so make everything bigger) means that any failure destroys some multiple of smaller payloads (in this case, human beings).

We notice airline crashes worldwide, even though far, far more people are killed in automobiles (by any metric you care to use).

[RedKraken]

I think hopper will work fine. No big unknowns here, and a lot of lower level risk retired (engines, autogen press, rcs thrusters).

Starship hops will be awesome, but i expect most problems to crop up (drag fin actuators and suborbital reentry testing, landing practice). Some top level risk retired here.

Booster hop test? Should not throw any problems if hopper tests are successful..

Starship (from booster) should get to orbit fine. Booster rtls (cradle away from pad) should be fine. More risk retired.

First orbital reentry attempt...might throw up some unusual results..or outlier parameters.

Or just explode. I hope not.

 

The next 3 years are going to be intense, even if stuff comes in late.

Aside from dragon2, FH, hopper, SSH and SS :

We get Ariane 6 due next year.

Vulcan and New Glenn due 2021.

SLS will stagger ahead like a crippled brontosaur.

Whatever the chinese, russians and indians decide to work on. Methalox and steel.

2020 Mars mission and James webb 2021.

Might see vector get to orbit.

Might see electric pumps and methane in small rocket format.

So much going on, makes me want to go back to school to skill-up.

[StrandedonEarth]

On 1/22/2019 at 7:38 PM, RedKraken said:

Might see electric pumps and methane in small rocket format.

IIRC Electron already uses electric pumps 

[wumpus]

On 1/21/2019 at 4:32 PM, DDE said:

I can name about fourteen reasons.

Seven.  Unless you are *really* on the ball and understood exactly what that foam hitting the tiles meant and fired the LES, a *Launch* Escape System wouldn't save the other seven (unless you are including cosmonauts who needed the Soyuz LES [and lived], but I thought there were only 5 or so).  But that really doesn't change your argument at all.

I know that at least one other time foam hit the tiles, so I don't know how many shuttles you would have to destroy to save the Columbia crew.  But you still want that LES (especially considering how well it has worked for Soyuz).

[sevenperforce]

2 hours ago, wumpus said:

Seven.  Unless you are *really* on the ball and understood exactly what that foam hitting the tiles meant and fired the LES, a *Launch* Escape System wouldn't save the other seven (unless you are including cosmonauts who needed the Soyuz LES [and lived], but I thought there were only 5 or so).  But that really doesn't change your argument at all.

I know that at least one other time foam hit the tiles, so I don't know how many shuttles you would have to destroy to save the Columbia crew.  But you still want that LES (especially considering how well it has worked for Soyuz).

Foam hit the tiles on every launch. It was just a thing that happened. Slinging a crew vehicle alongside a launch stack rather than placing it properly on top was always going to be a risk.

Columbia could have been saved, in theory, if the Shuttle had been designed from the ground up with an ejectable cabin containing closed-loop ECLSS and an integral single-use heat shield. But getting such a system to work properly would have introduced other failure modes. The chutes alone would have been a nightmare. 

[DDE]

2 hours ago, wumpus said:

Unless you are *really* on the ball and understood exactly what that foam hitting the tiles meant and fired the LES, a *Launch* Escape System wouldn't save the other seven

Engineering challenge accepted.

[sh1pman]

Wow, every time someone comes up with some new (even crazy) space stuff, it turns out that it has already been considered by soviets, sometimes even built.

[Bill Phil]

10 minutes ago, sh1pman said:

Wow, every time someone comes up with some new (even crazy) space stuff, it turns out that it has already been considered by soviets, sometimes even built.

Just like my dad says.

https://en.m.wikipedia.org/wiki/TRIZ

Might be relevat?

[magnemoe]

3 hours ago, DDE said:

Engineering challenge accepted.

Don't think that escape capsule would survive reentry. 
Its for launch fails or if you can not land safely. 

[tater]

5 hours ago, sh1pman said:

Wow, every time someone comes up with some new (even crazy) space stuff, it turns out that it has already been considered by soviets, sometimes even built.

Phil Bono had such a capsule on his designs (fully reusable, VTVL super heavy lifters, lol) from 1963. What year was that spaceplane?

Edited January 26, 2019 by tater

[Ultimate Steve]

Sorry to interrupt the argument, but if the whole extremely rapid reuse thing works out, at what point do you think will they stop livestreaming some launches because it won't be worth it any more?

[kerbiloid]

It's a pity that this nice Spiral capsule had been replaced in the later design with a dull sphere with small stabilizing fins on two telescopical rods.
(A photo is available in the book)

Also this conical one has a somewhat unusual place for the parachute (on the right side) with no visible door for the chute on top _{(so I still can't realize how should it be attached when descending).}

And its manner to land not on the heatshield - like we instinctively presume looking at it - but on the bottom edge looks... brave.
I.e. while in other cones the crew plops on back_(spine), in this capsule the pilot plops on back_(buttocks), so the space in the down corner under the seat is filled with that foam.
Taking into account how often the capsules hit the ground with horizontal speed, this original version of the capsule looks very optimistic.

6 hours ago, Bill Phil said:

https://en.m.wikipedia.org/wiki/TRIZ

A kind of "for everything good, against everything bad". Some esoteric theory of a person whose own inventions (not that "40000 patents") one can try to find out...

Edited January 26, 2019 by kerbiloid

[Xd the great]

2 hours ago, Ultimate Steve said:

Sorry to interrupt the argument, but if the whole extremely rapid reuse thing works out, at what point do you think will they stop livestreaming some launches because it won't be worth it any more?

Best case: some 3 years after the proven reuseability of starship.

Public forgets things fast.

[Terwin]

11 hours ago, Ultimate Steve said:

Sorry to interrupt the argument, but if the whole extremely rapid reuse thing works out, at what point do you think will they stop livestreaming some launches because it won't be worth it any more?

I expect that the engineers at the assembly facilities will always be interested in watching their latest baby take to the sky, and letting any interested third parties watch as well is free advertising.

They may well drop any added voice-overs(may have happened already) but there is no real added cost to letting the public watch the stream that they send back to the factory, and the publicity is of non-zero value, so why stop?

It is not like they don't want the cameras and telemetry just in case something goes wrong with a launch, so dropping the live-stream would only save them a little bit of internet bandwidth, which is generally pretty cheap at corporate rates.

[tater]

The (operational) B-58 bomber had an ejection pod:

 

[kerbiloid]

As well XB-70 and F-111 did.
 

Spoiler

http://www.ejectionsite.com/xb70caps.htm

Spoiler

 

Edited January 26, 2019 by kerbiloid

[Brotoro]

But the only time such ejection pods were used in a real emergency was during the crash of an XB-70... and one capsule failed to eject (the pilot died) and the other capsule crushed the arm of the other pilot when the capsule slammed shut, and he landed with severe injuries.

[magnemoe]

24 minutes ago, Brotoro said:

But the only time such ejection pods were used in a real emergency was during the crash of an XB-70... and one capsule failed to eject (the pilot died) and the other capsule crushed the arm of the other pilot when the capsule slammed shut, and he landed with severe injuries.

XB-70 system was over complicated, its an ejection seat with an closeable cover. F-111 idea is easier but also heavier. 
Putting pod on the top of the starship will have it work like any other capsule. Except that it will have an solid rocket engine inside the crew compartment
Yes you will remove the starting charge one in orbit and put it back before deorbit.

[kerbiloid]

23 minutes ago, magnemoe said:

XB-70 system was over complicated, its an ejection seat with an closeable cover. 

It was, for a single-seat capsule.

Though any escape cabin should anyway either use an overcomplicated splittable/openable nose,

or a 2-stage ejection: first throw it perpendicularly, then ignite prograde.
Like they do

Spoiler

 

 

Edited January 29, 2019 by kerbiloid

[DDE]

1 hour ago, kerbiloid said:

or a 2-stage ejection: first throw it perpendicularly, then ignite prograde.

I know of a Northrop Grumman project that involved a gelled IRFNA-hydrazine engine for this kind of aggressive but precise maneuvering... but it’s not the problem. At XB-70’s operational speeds, getting exposed to an outside airstream in a flight suit is fatal, which is why this sort of a shell was needed.

And short of launching the pilot out of the exhaust pipe I don’t see a way to cushion that encounter, no matter what elaborate trajectory your escape seat follows.

[kerbiloid]

51 minutes ago, DDE said:

At XB-70’s operational speeds, getting exposed to an outside airstream in a flight suit is fatal, which is why this sort of a shell was needed.

I guess, @magnemoe means not the capsule itself but the way of ejection when the pilot first moves back (on rails?), into that capsule, and only then ejects.
So, a 2-stage process: preliminary short movement in one direction, then launch into the perpendicular one.

In the video it's also 2-stage: short ejection impulse, then launch into a custom (here - perpendicular) direction.

Compare this to the mentioned Spiral and other such 1-stage ejection systems which launch the capsule prograde through the nose (either through the doors like on Spiral, or after jettisonning the top half of the nose).

P.S.
And imho this would probably allow to put a Gemini-like capsule into a Dreamchaser-like spaceplane, first shortly ejecting it up with small pad engines, then jettisonning the pad and pushing the capsule prograde with a toroidal rocket module behind.
Anyway the Dreamchaser design has a cabin bulb which could use the capsule cone as a forehead.

Edited January 29, 2019 by kerbiloid

[DDE]

3 hours ago, kerbiloid said:

And imho this would probably allow to put a Gemini-like capsule into a Dreamchaser-like spaceplane, first shortly ejecting it up with small pad engines, then jettisonning the pad and pushing the capsule prograde with a toroidal rocket module behind.

Great, now I want to install KSP and build jets with the Mk 1 command pod.

Hell, I’ve tried picturing how to strap a capsule into Shuttle’s hull envelope.

[kerbiloid]

3 minutes ago, DDE said:

Hell, I’ve tried picturing how to strap a capsule into Shuttle’s hull envelope.

I would add that this allows to eject the cabin on both vertical and horizontal launch methods (from a rocket and from a carrier plane).