Skylon

SpaceX Discussion Thread

Recommended Posts

 

Share this post


Link to post
Share on other sites
4 minutes ago, sevenperforce said:

It's easy to forget just how freaking unprecedented this is.

Well, other than the Space Shuttle, of course.

Share this post


Link to post
Share on other sites
4 hours ago, tater said:

They got docs about road closures, and specifics of moving it Eastbound in westbound lanes, along with total road closures. It will then go to a barge on the Indian River, and they have asked to be able to move it next month.

Heh, I love the part where he says “[something something the Shuttle’s external tank]... which is slightly smaller than Starship.” :D

It sounds like they’re gonna move it in two sections from that article. Slightly disappointing we won’t get to see it standing tall where it is, but it does make the move in only a few more weeks that much more plausible. 

Share this post


Link to post
Share on other sites

Is this "starship" we see pictures of nothing but a hollow shell? When do they put the insides in?

Also, while a prototype won't need them, a functional vehicle will need doors, hatches, etc. Will they still use this stacked ring method of construction? (That is how airplanes are built, usually, so it's entirely possible.)

Share this post


Link to post
Share on other sites
28 minutes ago, mikegarrison said:

Well, other than the Space Shuttle, of course.

There's nothing right now to indicate anything like the sort of teardown Shuttle had between reflights, though (on the flip side, Shuttle did EDL from Orbit, which is substantially more taxing than from 2 km/s like the F9 booster).

11 minutes ago, mikegarrison said:

Is this "starship" we see pictures of nothing but a hollow shell? When do they put the insides in?

There are images and vids of them lowering stuff into the tube. One looked like the thrust structure.

Share this post


Link to post
Share on other sites
Posted (edited)
7 minutes ago, tater said:

There's nothing right now to indicate anything like the sort of teardown Shuttle had between reflights

a) SpaceX has never been forthcoming about this. They have said they *want* to do quick and simple turnarounds, but they haven't ever said much about what they are currently doing right now.

b) SpaceX has never turned a booster around faster than the best turnaround times for the Shuttles, arguing that possibly the refit (or at least inspection) is a lot more comprehensive than many people are assuming.

Edited by mikegarrison

Share this post


Link to post
Share on other sites
2 minutes ago, mikegarrison said:

a) SpaceX has never been forthcoming about this.

b) SpaceX has never turned a booster around faster than the best turnaround times for the Shuttles, arguing that possibly the refit (or at least inspection) is a lot more comprehensive than many people are assuming.

Agreed, though I think that there were far more employees working on Shuttle than are in FL for SpaceX right now. If we had some idea of the relative number of employees, I suppose we could do some Kremlinology on it. They've done a few in something like 2.5 months, but of those times, at least a week is usually getting the booster back to port, on a truck, etc. The same team in FL in that period also seems to be getting other launches ready... but yeah, we have no idea.

Share this post


Link to post
Share on other sites
1 minute ago, tater said:

we have no idea.

That's all I'm saying here. Could be a lot, could be a little. The one piece of hard data we have is the actual demonstrated turnaround times for flight hardware.

Share this post


Link to post
Share on other sites
6 minutes ago, tater said:
14 minutes ago, mikegarrison said:

 

Agreed, though I think that there were far more employees working on Shuttle than are in FL for SpaceX right now. If we had some idea of the relative number of employees, I suppose we could do some Kremlinology on it. They've done a few in something like 2.5 months, but of those times, at least a week is usually getting the booster back to port, on a truck, etc. The same team in FL in that period also seems to be getting other launches ready... but yeah, we have no idea.

I think the gap between the fastest falcon and fastest shuttle is only 20 days. 54 vs. 74 I think.

Share this post


Link to post
Share on other sites
4 minutes ago, Ultimate Steve said:

I think the gap between the fastest falcon and fastest shuttle is only 20 days. 54 vs. 74 I think.

That sounds right. The only employee numbers I tend to see say that there were 25,000 employees in "Shuttle Operations," but I have no idea how many of those were actually hands-on working on the vehicles. We'd need man hours per vehicle refurb to really compare. Maybe a Starlink launch pair will show us a number that we don't have to wonder about much.

Share this post


Link to post
Share on other sites
2 hours ago, tater said:

Agreed, though I think that there were far more employees working on Shuttle than are in FL for SpaceX right now. If we had some idea of the relative number of employees, I suppose we could do some Kremlinology on it. They've done a few in something like 2.5 months, but of those times, at least a week is usually getting the booster back to port, on a truck, etc. The same team in FL in that period also seems to be getting other launches ready... but yeah, we have no idea.

This, also they have plenty of first stages, it makes sense to plan for long time between reuse if they can in case an stage can not be reused. 

Share this post


Link to post
Share on other sites
Posted (edited)

There are many reasons why this will never be a 1:1 correspondence (Shuttle was a manned orbiting lab, not a first stage booster!), but it still rubs me wrong when people talking about SpaceX implicitly dismiss the really groundbreaking contribution that the Shuttle did make to space reusability.

It's not a binary choice between "SpaceX is completely innovative" and "SpaceX is completely derivative".

Edited by mikegarrison

Share this post


Link to post
Share on other sites
1 minute ago, mikegarrison said:

There are many reasons why this will never be a 1:1 correspondence (Shuttle was a manned orbiting lab, not a first stage booster!), but it still rubs me wrong when people talking about SpaceX implicitly dismiss the really groundbreaking contribution that the Shuttle did make to space reusability.

Such different vehicles, it's really hard to compare, and as you say, boosters != orbital spacecraft.

Still, the goals are important to consider. When under dev, Shuttle was pitched as aircraft like turn around, and flights upwards of 1/week (I recall reading that they pushed of >40/year as a goal to have the launch costs for payloads equal to Titan variants). If that was an actual goal, it was clearly an abject failure in that regard. If F9 booster reuse reduces costs beyond expendable at all, it's a success.

Share this post


Link to post
Share on other sites
1 minute ago, tater said:

Still, the goals are important to consider. When under dev, Shuttle was pitched as aircraft like turn around, and flights upwards of 1/week (I recall reading that they pushed of >40/year as a goal to have the launch costs for payloads equal to Titan variants). If that was an actual goal, it was clearly an abject failure in that regard. If F9 booster reuse reduces costs beyond expendable at all, it's a success.

OK, seems like you massively shifted the goalposts between these two sentences. Since shuttle didn't have a 1 wk turnaround, it was an abject failure, but if F9 reduces costs at all, it's a success?

Is there any doubt that reusing the Shuttles was cheaper than building a new one for every launch? By that second metric, then it was a success too.

Musk is claiming the Starship will have overnight turnaround capability -- so if it never does, would it be an abject failure no matter what else it does? I don't think so.

And just to be clear, I think the Shuttle was a great success. And so is Falcon 9.

Share this post


Link to post
Share on other sites
Posted (edited)
52 minutes ago, mikegarrison said:

OK, seems like you massively shifted the goalposts between these two sentences. Since shuttle didn't have a 1 wk turnaround, it was an abject failure, but if F9 reduces costs at all, it's a success?

That's because that was the math they did to have Shuttle as cheaper than the expendable vehicles it was replacing for sat launch. To the extent the dev era pitch was not blowing smoke, it failed as the planned, cheap space truck. It was a Bugatti space truck ;) Drive it to the dump, then you have to put a new set of tires on it for $30,000. Doesn't mean it wasn't an awesome truck... but expensive.

Quote

Is there any doubt that reusing the Shuttles was cheaper than building a new one for every launch? By that second metric, then it was a success too.

As a crew vehicle? Sure, but Shuttle ended up lofting sats with PAMs, etc, and those launches were grossly more expensive than expendables would have been (think that was something like 75 missions (sat deployment)). So all those missions need to be compared to a regular, expendable vehicle launch cost (which would have been around a billion $ cheaper per launch), not the cost of throwing Shuttle away. With the Orbiter counted as payload, Shuttle was a decent ~$12,000/kg to LEO. Just counting the (max) payload, it was more like ~$53,000/kg. If the sat wasn't 24 tons, it was linearly more. TDRS was like 1/10th that mass, so more like 500k$/kg.

 

Quote

Musk is claiming the Starship will have overnight turnaround capability -- so if it never does, would it be an abject failure no matter what else it does? I don't think so.

And just to be clear, I think the Shuttle was a great success. And so is Falcon 9.

There are a number of metrics for Starship success. Starship will be a success for LEO/cislunar if it doesn't lose money. Or if it reduces cost to orbit. If the dev cost is low enough, it can even be a success in failure, assuming they learn a better way, and end up succeeding with a design changed with that new knowledge.

Shuttle was successful in many ways (certainly as a tech demonstrator, it was an amazing piece of hardware), and a failure in others (notably cost/safety). In the latter case, just considering crew, any capsule design would have had better LOC stats (since LES would have resulted in no LOC for Challenger, and while capsules have other reentry failure modes, heatshield damage on launch from falling debris isn't one of them). Cost... Well, it was really, really expensive.

 

I want a flying water tower...

 

Edited by tater

Share this post


Link to post
Share on other sites
3 hours ago, mikegarrison said:

That's all I'm saying here. Could be a lot, could be a little. The one piece of hard data we have is the actual demonstrated turnaround times for flight hardware.

Can we be sure how deep is the turnaround at all?.. What part of a reused stage is actually reused rather than replaced,
The only thing we can be sure: unique burnt spots on the hull.

But they insidiously wash the rockets...

Share this post


Link to post
Share on other sites
35 minutes ago, kerbiloid said:

Can we be sure how deep is the turnaround at all?.. What part of a reused stage is actually reused rather than replaced,
The only thing we can be sure: unique burnt spots on the hull.

But they insidiously wash the rockets...

Traditionally, if you keep the keel, you can replace the entire rest of a ship and it remains "the same ship".

Share this post


Link to post
Share on other sites
Posted (edited)
6 hours ago, mikegarrison said:

Traditionally, if you keep the keel, you can replace the entire rest of a ship and it remains "the same ship".

I saw a couple P-38s being reconstructed at the National Museum of WW II Aviation in Colorado Springs... Seeing the jigs they were using to make new parts, and all the fresh Al without zinc chromate green paint on it yet, I asked the guide how much of the finished aircraft would be original... he said "The serial number plates." LOL.

Edited by tater

Share this post


Link to post
Share on other sites
10 hours ago, kerbiloid said:

Can we be sure how deep is the turnaround at all?.. What part of a reused stage is actually reused rather than replaced,
The only thing we can be sure: unique burnt spots on the hull.

But they insidiously wash the rockets...

I thought they generally did not wash the boosters (aka 'sooty') and just cleaned 'pin stripes' for checking seams.

I could not say how much work was done with engines and internals, but the external shells of the reused F9 boosters seem to have minimal handling after landing(or else more of the soot would be rubbed/washed off). 

Share this post


Link to post
Share on other sites
Posted (edited)
36 minutes ago, Terwin said:

I could not say how much work was done with engines and internals

That's what I mean.
As there is much more time between the same stage launches (months?) than between airplane flights, they probably not just check it like an airliner between the flights, but disassermble it.
So, probably they consider some parts (maybe, whole engines or legs) unreliable and replace them with just manufactured ones.
So, we know neither real delta-cost of the flight (is it really less than a single0use one, or this is just a dumping), nor how much reusable is the stage actually.

Edited by kerbiloid

Share this post


Link to post
Share on other sites
5 minutes ago, kerbiloid said:

That's what I mean.
As there is much more time between the same stage launches (months?) than between airplane flights, they probably not just check it like an airliner between the flights, but disassermble it.
So, probably they consider some parts (maybe, whole engines or legs) unreliable and replace them with just manufactured ones.
So, we know neither real delta-cost of the flight (is it really less than a single0use one, or this is just a dumping), nor how much reusable is the stage actually.

You can see that the stage itself is used, and you can also see that the engines have been fired. A few of the reused boosters look like they may have had an engine swap (new engines are mirror shiny).

https://spacenews.com/spacex-gaining-substantial-cost-savings-from-reused-falcon-9/

Quote

At the 33rd Space Symposium in Colorado, SpaceX President Gwynne Shotwell has revealed that the company spent "substantially less than half" the cost of a new first stage for the Falcon 9 reflight. While she didn't mention specific figures, that means huge savings, since the rocket's first stage accounts for around 75 to 80 of its total cost.

That was for SES-10, the first reflight. Refurbishment has likely decreased since then.

But the benchmark is "substantially less than half" the cost of a new stage 1.

Share this post


Link to post
Share on other sites

@ZooNamedGames look above at reuse price. internal costs have clearly decreased. however they have not reduced selling cost by much, to assist in funding of starship.

Share this post


Link to post
Share on other sites
6 minutes ago, Barzon Kerman said:

@ZooNamedGames look above at reuse price. internal costs have clearly decreased. however they have not reduced selling cost by much, to assist in funding of starship.

What's the source?

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.