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

[Rakaydos]

59 minutes ago, Starman4308 said:

The number Musk envisions is irrelevant. The number that will actually happen is the more important figure, and it's not going to hit even one per day anytime soon.

The stainless steel hopper is scheduled to fly every other day, so daily flight probably arnt as far away as you think.

[sh1pman]

20 hours ago, tater said:

I can see it making little difference, but I can't see it making it less safe than nothing, there are people alive today because of LES systems, and more dead for lack of them. Zero dead because of them.

Well... three dead because of LES, actually. They were ground personnel, but I guess it counts?

http://www.russianspaceweb.com/soyuz-7k-ok-no1-explosion.html

[Starman4308]

38 minutes ago, Rakaydos said:

The stainless steel hopper is scheduled to fly every other day, so daily flight probably arnt as far away as you think.

They might create the capability. Capability that spends most of its time in a hangar because there are no payloads left to launch.

[kerbiloid]

If they will be launching it daily, it will take just several years to cover the sky with quick-and-dirty noname space platforms covered with antennas.

The space is not made of rubber.

Edited February 6, 2019 by kerbiloid

[tater]

48 minutes ago, Rakaydos said:

The stainless steel hopper is scheduled to fly every other day, so daily flight probably arnt as far away as you think.

Hopping != orbital flight.

20 minutes ago, sh1pman said:

Well... three dead because of LES, actually. They were ground personnel, but I guess it counts?

I don't really count that. If you are gonna count that, we might as well count deaths related to producing the hydrocarbons in the fuel. Even if counted, I suppose we need to compare the chances of such a case with Soyuz to presumed chances on a new system, ideally built to higher safety standards. Heck, right now rockets also have pyros to rip the tanks apart for range control.

 

Related to some other posts, it ends up being a marketing issue if the customers are not-NASA, and it ends up being the ability to show better than 1:270 LOC probabilities to NASA if NASA is to be the customer.

So NASA is far, far more likely as a crew customer at some point, since those lowball numbers are far easier to show.

For anyone else, redundant safety systems (like LES) are a plus for sales, IMO.

[sevenperforce]

1 hour ago, tater said:

I don't really count that. If you are gonna count that, we might as well count deaths related to producing the hydrocarbons in the fuel. Even if counted, I suppose we need to compare the chances of such a case with Soyuz to presumed chances on a new system, ideally built to higher safety standards. Heck, right now rockets also have pyros to rip the tanks apart for range control.

These deaths absolutely count. An installed, operational LES malfunctioned and caused a LOV that killed three people. No, it was not a nominal event, but LES is for off-nominal events. That is the point.

Analogy to ejection seats is a good one. Ejection seats have malfunctioned and killed people before. It's not a high likelihood, so people still use them, but it has happened.

But adding ejection seats to the cockpit of a Boeing 747 would make it objectively less safe, because the odds of ejection seat malfunction/accidental trigger are almost certainly higher than the odds of needing to eject from a commercial airliner.

I would be a fan of ejection seats on Starship, at the very least. But there may be a point at which they make things less safe, not more safe, and at that point I would no longer be a fan.

[tater]

1 hour ago, sevenperforce said:

These deaths absolutely count. An installed, operational LES malfunctioned and caused a LOV that killed three people. No, it was not a nominal event, but LES is for off-nominal events. That is the point.

Analogy to ejection seats is a good one. Ejection seats have malfunctioned and killed people before. It's not a high likelihood, so people still use them, but it has happened.

Yeah, but it doesn't make warplanes less safe. They've saved more lives then they have cost. How many NASA LES failures have there been? (I'm guessing about as many as NASA crew vehicles with holes mistakenly drilled in them).

 

1 hour ago, sevenperforce said:

But adding ejection seats to the cockpit of a Boeing 747 would make it objectively less safe, because the odds of ejection seat malfunction/accidental trigger are almost certainly higher than the odds of needing to eject from a commercial airliner.

If the airliner only contained the flight deck crew, it would make sense to trade any tiny increased chance of LOV for the lives of the crew.

Less safe doesn't matter if the crew survives. I'd trade a Starship for the occupants. Others might not, as long as they weren't the occupants in question.

 

Quote

I would be a fan of ejection seats on Starship, at the very least. But there may be a point at which they make things less safe, not more safe, and at that point I would no longer be a fan.

Ejection seats would never be useful. The ones on the Shuttle had only a couple places where they could possibly be used (instead of ditching, for example). Seems like most likely failures are catastrophic losses, then some sort of failure that leaves them suborbital, though if Starship itself is a near SSTO, then once a certain amount of booster is used, the abort mode might be into a low orbit and subsequent landing. Any S2 failure (Starship itself) would only be survivable with some sort of LES (past simple engine-out failures as long as it can land with remaining engines).

Edited February 6, 2019 by tater

[Starman4308]

Okay, let me try to clear this up a bit.

@tater, would you agree in the abstract that an LES could be a bad idea if the Starship became very reliable?

@sevenperforce, please try to understand we're coming from the practical assertion that the Starship has no proven reliability record and is unlikely to accrue such a record for a long, long time, even if it does actually have the reliability to hit the range where skipping the LES is a good idea.

Overall, this is a thread about whether we think Superheavy/Starship will work. While "work" is ill-defined, I'll give my 2 cents on a few levels of "work".

 

"Work" as in fly: Yes. SpaceX has not demonstrated the staggering levels of incompetence that would be required for Starship/Superheavy to be incapable of orbital flight.

"Work" as in land: Probably also yes.

"Work" as in become an economical launch vehicle on par with existing launch vehicles: Reasonably good odds. I strongly suspect the $9M/launch cost will be outright fantasy, but there's definitely wiggle room for unforeseen issues between the best-case scenario and "still good enough to compete".

"Work" as in become this ultra-vehicle with airliner levels of reliability with multiple flights per day: Outright fantasy. Something this complicated, there will be design skeletons in design closets.

[sevenperforce]

59 minutes ago, tater said:

Yeah, but it doesn't make warplanes less safe. They've saved more lives then they have cost. How many NASA LES failures have there been? (I'm guessing about as many as NASA crew vehicles with holes mistakenly drilled in them).

It's math.

Given a proposed safety feature: if Σ(P_F,P_A)*P_S > ΣP_L (where P_F is probability of vehicle failure, P_A is probability of vehicle accident, P_S is probability of the safety feature working properly, and ΣP_L is the sum of probabilities of ways the safety feature could accidentally kill you), then you should have the safety feature. If not, then don't.

For the safety feature of ejection seats on a jet fighter, it is very clear that Σ(P_F,P_A)*P_S is greater than ΣP_L, even though ΣP_L is most definitely greater than zero. For an attack helicopter, they are pretty nearly equal. For a Chinook they are equal or worse; for a commercial airliner Σ(P_F,P_A)*P_S is demonstrably less than ΣP_L.

The same math works for seat belts on various craft. For a passenger vehicle, Σ(P_F,P_A)*P_S > ΣP_L. For a speedboat, Σ(P_F,P_A)*P_S = ΣP_L. For a 4-wheeler, Σ(P_F,P_A)*P_S < ΣP_L.

1 hour ago, tater said:

If the airliner only contained the flight deck crew, it would make sense to trade any tiny increased chance of LOV for the lives of the crew.

Then why don't commercial cargo planes have ejection seats?

59 minutes ago, tater said:

Less safe doesn't matter if the crew survives. I'd trade a Starship for the occupants. Others might not, as long as they weren't the occupants in question.

The problem is still that ΣP_L can be shockingly large. Consider a full-envelope capsule-cabin LES with independent abort engines and heat shield. That's all very well and good...but you now have to sum a bunch of new probabilities, like "chance that new structural problems will case increased entry failure rate" and "chance that abort fuel will leak on orbit" and "chance of unintended fire during blackout trajectory" and so forth.

59 minutes ago, tater said:

Ejection seats would never be useful. The ones on the Shuttle had only a couple places where they could possibly be used (instead of ditching, for example).

That's because the STS used ginormous fire-belching tubes of bomb strapped on either side. Ejection seats on the Starship would have far less hazard to contend with and could be used all the way through MaxQ (on the way up) or for a landing failure (whether at engine ignition or at touchdown). 

59 minutes ago, tater said:

Seems like most likely failures are catastrophic losses, then some sort of failure that leaves them suborbital, though if Starship itself is a near SSTO, then once a certain amount of booster is used, the abort mode might be into a low orbit and subsequent landing. Any S2 failure (Starship itself) would only be survivable with some sort of LES (past simple engine-out failures as long as it can land with remaining engines).

The Starship can handle virtually any Superheavy failure.

[Starman4308]

9 minutes ago, sevenperforce said:

The problem is still that ΣP_L can be shockingly large. Consider a full-envelope capsule-cabin LES with independent abort engines and heat shield. That's all very well and good...but you now have to sum a bunch of new probabilities, like "chance that new structural problems will case increased entry failure rate" and "chance that abort fuel will leak on orbit" and "chance of unintended fire during blackout trajectory" and so forth.

Right now, P_F is distressingly large for orbital launch vehicles. There is no indication Starship/Superheavy will be any different.

And separating (P_F,P_A) just makes things needlessly confusing. For the purposes of this discussion, "failure" is failure to protect passengers.

Furthermore, there are reasons beyond that simple mathematical equation for having or skipping safety features:

1) The safety feature is expensive. This is most likely the case for something like a cargo aircraft: the probability of failure is so low that nobody's willing to shell out for expensive ejection seats.

2) The safety feature has an excessive penalty to performance. For example, by the time you add ejection seats to an attack helicopter, you might have added so much mass that you've made it more dangerous by reducing its ability to not get shot down in the first place.

3) Cultural/bureaucratic inertia. See the lack of seatbelts in many buses.

4) Marketing (which is a bit part of Tater's point).

5) There is sufficient uncertainty in failure probability to confidently skip safety measures... like an experimental vehicle that most closely resembles a set of vehicles with an awful habit of exploding.

I'm also pretty sure that, like most probability-based things, it's going to be a product, not a summation.

17 minutes ago, sevenperforce said:

The problem is still that ΣP_L can be shockingly large. Consider a full-envelope capsule-cabin LES with independent abort engines and heat shield. That's all very well and good...but you now have to sum a bunch of new probabilities, like "chance that new structural problems will case increased entry failure rate" and "chance that abort fuel will leak on orbit" and "chance of unintended fire during blackout trajectory" and so forth.

Probability of increased failure caused by a Starship LES should be fairly small if it is kept simple and you're not the 1960s Soviets who have been launching orbital vehicles for less than a decade.

19 minutes ago, sevenperforce said:

That's because the STS used ginormous fire-belching tubes of bomb strapped on either side. Ejection seats on the Starship would have far less hazard to contend with and could be used all the way through MaxQ (on the way up) or for a landing failure (whether at engine ignition or at touchdown). 

Ejection at supersonic velocities is very unsafe... as is ejection at hypersonic velocities in near-vacuum. I do not consider them a viable LES.

Also, Gemini would've been a better example... for which the ejection seats were considered borderline useless.

22 minutes ago, sevenperforce said:

The Starship can handle virtually any Superheavy failure.

[Citation needed]

[tater]

1 hour ago, sevenperforce said:

Then why don't commercial cargo planes have ejection seats?

Because they have billions of hours of flight data to support the fact that they are safe, everry hour of which they are at safety risk (or traveled distance if you prefer, or a combination of take off landing cycles plus distance).

When Starship has millions or billions of liftoff landing cycles, yeah, it'll be safe (assuming it has airline levels of losses per flight cycle).

1 hour ago, sevenperforce said:

The Starship can handle virtually any Superheavy failure.

No it can't.

Superheavy has an RUD, there is no way the Raptors are chilled down, and instantly start to separate faster than the shockwave/debris (or nearly instant aerodynamic issues).

Even if it does, where does it land, and how much propellant is required to burn off before landing (unless it can abort to orbit, which it likely can in many cases, assuming it survived the fireball/aero stress of the Superheavy failure).

1 hour ago, sevenperforce said:

That's because the STS used ginormous fire-belching tubes of bomb strapped on either side. Ejection seats on the Starship would have far less hazard to contend with and could be used all the way through MaxQ (on the way up) or for a landing failure (whether at engine ignition or at touchdown). 

They wouldn't even work on the pad.

[Rakaydos]

So I re-raised the idea of escape capsules over on NSF. You might be interested in the views of people who are a little more serious about it than people who follow a space-themed computer game.

https://forum.nasaspaceflight.com/index.php?topic=47052.msg1908823#msg1908823

[tater]

1 hour ago, Starman4308 said:

Okay, let me try to clear this up a bit.

@tater, would you agree in the abstract that an LES could be a bad idea if the Starship became very reliable?

Absolutely. I think it's possible to demonstrate high levels of safety in the real world. I think notional estimates of LOC/LOV probability are... notional.

 

Quote

@sevenperforce, please try to understand we're coming from the practical assertion that the Starship has no proven reliability record and is unlikely to accrue such a record for a long, long time, even if it does actually have the reliability to hit the range where skipping the LES is a good idea.

Overall, this is a thread about whether we think Superheavy/Starship will work. While "work" is ill-defined, I'll give my 2 cents on a few levels of "work".

"Work" as in fly: Yes. SpaceX has not demonstrated the staggering levels of incompetence that would be required for Starship/Superheavy to be incapable of orbital flight.

"Work" as in land: Probably also yes.

I agree through here completely.

 

Quote

"Work" as in become an economical launch vehicle on par with existing launch vehicles: Reasonably good odds. I strongly suspect the $9M/launch cost will be outright fantasy, but there's definitely wiggle room for unforeseen issues between the best-case scenario and "still good enough to compete".

I'm not sure on costing, honestly. I think that propellant costs plus some operational costs having the total cost in that ballpark are not crazy.

 

Quote

"Work" as in become this ultra-vehicle with airliner levels of reliability with multiple flights per day: Outright fantasy. Something this complicated, there will be design skeletons in design closets.

Yeah, I'm not at all sanguine on P2P.

I dearly wish it to be true, really, I'd buy a ticket that cost as much as a first-class across the Pacific RT ticket right now if it was as safe as an airliner.

7 minutes ago, Rakaydos said:

So I re-raised the idea of escape capsules over on NSF. You might be interested in the views of people who are a little more serious about it than people who follow a space-themed computer game.

https://forum.nasaspaceflight.com/index.php?topic=47052.msg1908823#msg1908823

I read your post. Throwing Dragons in the cargo bay is not the same thing as designing a crew vehicle with an integral LES capability.

In addition, some of those comments are not really any different than those here (quite a number of the people here are also on NSF).

I think it's certainly possible for them to demonstrate commercial crew levels of safety using the same criteria they use now to evaluate designs---without LES.

My disagreement is not with "safe enough to fly astronauts," it's "as safe as an airliner" which is literally several orders of magnitude safer than any rocket, ever.

Literally any LOV with any Starship or Superheavy would reset the safety to 1 in X. They could fix the issue that caused the failure, but the real-life average would be ruined. I don't care what the theoretical risk of a 787 is, I care what the actual loss rate is. I'd say the same about a crew vehicle once it has flown.

Edited February 7, 2019 by tater

[Starman4308]

6 minutes ago, Rakaydos said:

So I re-raised the idea of escape capsules over on NSF. You might be interested in the views of people who are a little more serious about it than people who follow a space-themed computer game.

https://forum.nasaspaceflight.com/index.php?topic=47052.msg1908823#msg1908823

To the best of my knowledge, those are still random Internet commenters and space enthusiasts with no more authority on the subject than you or I.

Preaching to the skies about "airliner-like reliability" won't make Starship as reliable as an airliner. Flying it tens of thousands of times will... and there just aren't enough payloads lined up for that in the forseeable future.

[tater]

23 minutes ago, Starman4308 said:

To the best of my knowledge, those are still random Internet commenters and space enthusiasts with no more authority on the subject than you or I.

Preaching to the skies about "airliner-like reliability" won't make Starship as reliable as an airliner. Flying it tens of thousands of times will... and there just aren't enough payloads lined up for that in the forseeable future.

Exactly.

Starlink is their payload, but it's a matter of launch costs for them. If they can operate at a fraction of F9 costs, then they have to decide if they want BFR cadence, or lower cost for Starlink. If the former case, they fly many more launches with fewer sats, if the latter, they cram in as many as possible.

I think demonstrating commercial crew levels of safety might be possible from Starlink alone. Halfway through that, they already beat Shuttle and Soyuz.

I'm not rabid about LES, I just think they need to demonstrate safety, not calculate it (I think those guestimates are just that).

[kerbiloid]

5 hours ago, sevenperforce said:

Then why don't commercial cargo planes have ejection seats?

Because there are civilians onboard

Spoiler

(expeditors and so on)

 

Edited February 7, 2019 by kerbiloid

[Xd the great]

15 minutes ago, kerbiloid said:

Because there are civilians onboard

  Reveal hidden contents

(expeditors and so on)

 

And they love to "press this button and see what happens"

[kerbiloid]

1 hour ago, Xd the great said:

And they love to "press this button and see what happens"

No. They are not trained and sporty, so they can hardly survive the ejection.

So, the cargo planes are still passenger planes.

***

If the pilot has a chute, while the passengers don't, the passengers will be suspecting that the crew can leave them onboard and bail out.

So, to avoid panic on every turbulence, it's better to take the chutes from the crew than to give them to the passengers (who anyway will fail the jump).

So the passengers won't be holding a knife against the pilot's throat, screaming: "Give me your chute! Drive the plane!"
(While the air marshal holds the cabin door open).

So, the civil cargo planes just follow the common civil plane rules.

Edited February 7, 2019 by kerbiloid

[RedKraken]

<wild-ass speculation>

Within 2 years, we will know if full-reuse in steel is going to work (re-entry). Allow for quite a few fails (crashes, reentry damage) here. Pad1. Booster1.

Another 4 or 5 years of bedding in cargo SS like F9. Allow for a couple of mission fails (and 3 or 4 block improvements). Refueling sorted out. Pad2. Booster2.

GTO rideshares (carousel + 12t kickstages) for short-term cash.

Dozens of LEO missions for starlink long-term cash.

Tanker version starship.

Within 8 years, prestige missions to moon/mars....unmanned first, later crewed. Starlink half complete. Pad3. Booster3.

First P2P cargo routes within 10 years. Short range (2000km) with just suborbital starship config.. Long Range with suborbital stack. Offshore pads. 12m prototype.

Starlink complete w/ 2nd and 3rd gen sats.

Another 10 years to go for P2P cargo to go from exclusive to common.

</WAS>

[kerbiloid]

32 minutes ago, RedKraken said:

cargo routes

How much cargo per route?

On ground: a standard railway wagon carries ~70 t.
A train contsists of, say, ~50 wagons.
3500 t per route.

A standard sea container (TEU) contains ~20 t.
A medium-sized ship carries ~500..1000 TEU. The biggest - 10 times more.

So, a typical ground or sea cargo route delivers several thousand tonnes at once. (And is almost safe.)
How many is it in BFRs?

Yes, it takes a week. But what about the joy of foretaste?

Edited February 7, 2019 by kerbiloid

[Xd the great]

17 minutes ago, kerbiloid said:

How much cargo per route?

Probably 150 ton, can stretch to 200.

But hey, half an hour. Imagine all the fresh food...

[kerbiloid]

2 minutes ago, Xd the great said:

150 ton, can stretch to 200

What can be a 200 t cargo which you can't buy in your megalopolis?

(As the spaceports will unlikely be built in Armpit-Creek places, so a megalopolis anyway.)

5 minutes ago, Xd the great said:

But hey, half an hour. Imagine all the fresh food...

And unless you live right at the landing pad, a hour(s) to deliver it from there to your home.

[Xd the great]

7 minutes ago, kerbiloid said:

What can be a 200 t cargo which you can't buy in your megalopolis?

(As the spaceports will unlikely be built in Armpit-Creek places, so a megalopolis anyway.)

And unless you live right at the landing pad, a hour(s) to deliver it from there to your home.

Still, veeeeeeery fresh. 

Planes take days, truck takes hours, probably at least half a day.

[RedKraken]

22 minutes ago, kerbiloid said:

So, a typical ground or sea cargo route delivers several thousand tonnes at once. (And is almost safe.)
How many is it in BFRs?

....starship cargo does not compete with container ships. 

It will take time critical cargo off jets. Its not going to handle antonov sized loads....fedex only.

Its going to be the fastest door to door goods delivery on the planet. And the most expensive.

And people will pay.

If I need a critical part shipped from NY to London in 4hrs, i use starship.(and helicopters from the cargo hub out to the pad)

If i need it in 24 hrs, i use jetliner cargo.

If i need it in 10 days, i'll send it on a cargo ship....

Corporations will pay big, big money for 4hrs global door to door delivery.

Eventually, it will deliver people along with the cargo.

 

[sh1pman]

6 minutes ago, RedKraken said:

If I need a critical part shipped from NY to London in 4hrs, i use starship.(and helicopters from the cargo hub out to the pad)

4 hours? The rocket must already be waiting on the pad. Not sure if you can load your cargo at that point. 

There's also a good chance of scrub because of weather.