Starship is Go...

SpaceNut · 2020-02-06 20:12:26

Mk1 was built in Texas and after blowing its top is being work rather than building MK3
Mk2 is being built in Florida with MK4 as well seems to have been started.

So if we are going to have different engine counts and fuel tank sizes then the SN would identify a systems configuration number....

louis · 2020-02-07 18:13:33

A good video from Felix...

https://www.youtube.com/watch?v=HI_8cZwP5XA

X ray machines being used to inspect welds now (why not before? you might ask).

Some clues as to weight of the hull.

Starship launch - 20 Km flight 16 March (at the earliest).

louis · 2020-02-07 20:16:18

SpaceXcentric have a v similar narrative...

louis wrote:

A good video from Felix...
https://www.youtube.com/watch?v=HI_8cZwP5XA
X ray machines being used to inspect welds now (why not before? you might ask).
Some clues as to weight of the hull.
Starship launch - 20 Km flight 16 March (at the earliest).

louis · 2020-02-14 06:00:59

Felix has an excellent and encouraging update on Starship production:

https://www.youtube.com/watch?v=oXI1HOO4lFc

louis · 2020-02-17 15:19:33

Another exciting update from Felix on Starship:

1. Space X Starship production - milestones achieved on a daily basis.

2. Boca Chica buzzing with activity.

3. Space X fleshing out the stacks. Plumbing, avionics and electronics being installed.

4. Won't be RCS thrusters needed. Centre of mass problem reduced. Might go back to three leg design.

5. Detailed drawings from 3:40.

6. Zubrin interview with Musk.

7. Within one year, Space X will be employing 3000 people at Boca Chica. 2 Starships per week - mass production facility in BC.

8. Production costs - Starships will cost $5 million each.

9. No nuclear reactors. Zubrin pointed out 6-10 football fields of PV array would be required for Starship refuelling on Mars. Musk replied "Fine that's what we'll do." So does look like the first mission to Mars will be essentially solar powered on the surface.

10. First crewed ships will have 15-20 people on board...this seems to suggest we could see 30-40 people on Mission One. However, I would remain sceptical about that. Perhaps Musk is talking about the first few flights after Mission One. Trying to train up 40 people for Mission One sounds extremely challenging and resource intensive. But on the other hand, Musk does equate Mission One with the D Day Landings in comparison with the Apollo Landing on the Moon.

https://www.youtube.com/watch?v=mseWhaW43Wg

Given the recent news about the proposed IPO on Starlink, which should provide the capital for the early stages of the Mars colonisation programme, it does seem like Musk is unstoppable.

SpaceNut · 2020-02-17 15:55:15

Can anyone say moving target for performance and design...

louis · 2020-02-17 19:08:06

It is - for me - a surprising approach to designing something as complicated as an interplanetary rocket...I guess we have to accept that Musk uses an intuitive approach as well as a rational one and that does appear to pay dividends over time. I had assumed a lot of the principles and methods of rocket design had long ago been settled...seems I was wrong.

As long as Musk's rocket is ready for duty by 2025 at the latest, I will be happy.

SpaceNut wrote:

Can anyone say moving target for performance and design...

SpaceNut · 2020-02-17 19:49:32

You must remember that parts and especially electrical and electronic are obsolete these days in less than 7 years from start of use to end of life.

The only thing that is still some what new is the methane engines and even that is halfway through the 7 year cycle for the interface hardware...

RobertDyck · 2020-02-17 21:22:38

I bought my house in November 1990. It came with furnace, water heater, clothes washer, and dryer. The washer died just about when I moved in. The appliance service company said repair would cost more than a new replacement, so I got a new one. That was 1990, the new one is still running. In 2009 the natural gas clothes dryer quit. I brought in the same repair company, no other appliance "repair" company knew how to repair anything; they would only replace parts, and complained that dryer is so old they can't get parts. But Accurate Appliance was able to fix it. The main bearing for the blower failed. The V-belt (like a car engine) broke when he removed it. He said it looked like the original. He took the blower to his shop, removed the bearing and took it to a company that specializes in rebuilding bearings. After it was fixed, brought it back and re-installed. With a new V-belt. The natural gas company sent an inspector to ensure everything was Ok. The inspector said the points would be worn out. This dryer does not use a pilot light, it has a relay that strikes a piece of flint to steel to create a spark. So the gas is only on when the dryer is running. But he looked at the points, they were perfect. I'm a single guy, and use the clothes line in summer, so don't use the dryer that much. After I tried to find manufacturing date, but couldn't find such a plate on it. Found the manufacturer name and model number. When I phoned the manufacturer they said it was either built in 1961 or 1962; so it's older than I am. Assuming it's from 1961, it ran for 48 years before requiring service. Now it'll probably run at least another 25 years.

New appliances are designed to last 7 to 10 years. Why would I get a new one?

A number of years ago my electric water heater failed. When I bought the house there was a special deal from the electric company; the water heater was rented from them. Added to my monthly electric bill. But eventually the electric company wanted out of the deal, gave me an offer. I would pay just 3 more months at the same rate, then I would own the water heater. At that point it would be mine, no monthly rental, but it would be my responsibility if it failed. Shouldn't come as a big surprise that it failed one year later. Tank corroded through, water gushed out. I bought a new one, and installed with help of a couple friends.

Last year my furnace failed. That model furnace was made 1961, so the clothes dryer and furnace were probably installed the same time. Middle of winter, woke up to a very cold house. Called the natural gas company, they offer to do simple repairs for free. Found the gas valve failed, so replaced it. The natural gas company repairman was a certified pipe fitter, so qualified to install it. Then he found the heat exchanger had a crack. Flame was "rolling back"; that's what caused the valve to fail. He immediately turned off the gas and told me to get a heating contractor. Only one contractor was willing to come out to look at it. He tried to sell me a new furnace, and said it would have to be the newest and latest high efficiency furnace, which would require punching a hole in the basement wall for a new chimney and air intake, and running a water drain hose. I said thank you, and escorted him out. Learning what the appliance guy did with the dryer, taking the damaged part to a specialist, I opened the furnace and took out the heat exchanger myself. It wasn't easy, it was hard getting at all the screws, and it was damn heavy! But I did it. Carried it up the stairs with help from a friend. He had a truck to carry it to a welder. Found a welder online, ensured he knew how to weld that type of steel. The burners were cast iron, but the heat exchanger was mild steel. Inspected it myself, couldn't find any more cracks. But asked the welder to look for any cracks, or anything else that could fail. He said the welds from manufacture would eventually fail, so welded over them. My father was a welder; I may not be a welder myself, but know enough to recognize a good job. He did a really good job. Two burners, one heat exchange chamber above each burner, each chamber made of two pieces of stamped steel welded together. Some people think you can't weld to repair, but these were welded when the furnace was manufactured. Steel doesn't know the difference between manufacture vs repair; welding is welding is welding. Perhaps some new furnace with super thin sheet metal made of some exotic stainless steel alloy couldn't withstand the heat cycle of welding, but this was mild steel. No problems welding that. And the welder ground the weld over the crack smooth, so the heat exchanger would form an air-tight seal when re-installed. Again, good job! I re-installed myself. Asked a friend for help; tried to hold it while the friend put in the first screws. But he kept trying to pull the heat exchanger through the fire box. It won't fit through there, and you have to press the parts together to match screw holes. He claims he was a motorcycle mechanic, but a mechanic should at least understand how to match screw holes. Oh well, asked a different friend. He helped just long enough to get a couple screws in place to hold it. Then left, I installed the rest of the screws. And re-installed the burners. The air intakes for the burners fell off, so I had to put them back on. That meant their setting was lost, so re-adjusted them for optimal fuel/air mix. Looked up on the internet how to do it; turns out there are a couple YouTube videos. Wow! Ok, adjust until the flame is maximum blue. When it's most blue, that means most complete combustion. Turns out I had adjusted for cleaner combustion than it had been set before. Called the natural gas company to send over an inspector. He looked and found everything Ok. I told him that I did it myself, had a guy from his company replace the gas valve, and a welder do the welding, but effectively was my own heating contractor. The inspector's eyes went big; he re-inspected everything again. And again, and again. He had a carbon monoxide sensor, checked air in the basement, the box in front of the furnace, up the chimney, everything possible. Several times over. Found I did everything right. The furnace has worked ever since.

Point is with proper maintenance, things built rugged can last a lifetime. And on Mars you will have to be very self-sufficient. Could you fix your own furnace? On Mars you'll have to.

tahanson43206 · 2020-02-17 21:52:35

For RobertDyck re #509

Thanks for your detailed report of what would be a major repair and far beyond my capabilities.

I had not forgotten your mention of being cold in your home with the furnace out, and appreciate your follow up. I assumed you solved the problem, but had no idea (of course) what was involved!

Your closing line should be worrisome for future Mars settlers. Not everyone on Earth is capable of that degree of self sufficiency. The folks heading off to Mars would be well advised to think seriously about their collective dependency on machines. On Earth, in temperate climates, we can (and often do) enjoy periods of time when Ma Nature treats is pretty well, and makes few demands upon us. On Mars, that will NEVER be the case.

(th)

SpaceNut · 2020-02-17 21:56:52

The newer models are designed with energy savings for use that the old unit is greatly exceding otherwise we would be still driving model T's...
I do agree that somethings should be designed to last longer but for companies that make money on unit sales then that goes against the profit margin that they are looking for.

louis · 2020-02-21 19:14:22

https://www.youtube.com/watch?v=Qop-NFsugU0

First orbital flight of Starship could happen this year! Wouldn't that be a dream!! Space X do appear to be piling in resources to the project, so I don't think this is necessarily "Musk Pie in the sky".

louis · 2020-02-23 15:59:27

A clear concise update from Engineering Today on the Starship programme:

https://www.youtube.com/watch?v=Qx8uYH4RxXQ

Space X are travelling at speed!

SpaceNut · 2020-02-24 21:33:03

Really ! SpaceX Starship Will Have Wheels and Get Towed to Launch Pad

Screen-Shot-2020-02-24-at-9.48.40-AM-730x430.jpg

The SpaceX Starship and likely the Super Heavy Booster will have wheels so that they can be towed to the launch pad. Having wheels built into the vehicles will make them easier to move to launch pads and from where they land.

louis · 2020-02-25 19:30:32

Interesting! Sounds like we might be back to three legs as one of the Space X trackers suggests...

SpaceNut wrote:

Really ! SpaceX Starship Will Have Wheels and Get Towed to Launch Pad
https://www.nextbigfuture.com/wp-conten … 30x430.jpg
The SpaceX Starship and likely the Super Heavy Booster will have wheels so that they can be towed to the launch pad. Having wheels built into the vehicles will make them easier to move to launch pads and from where they land.

louis · 2020-02-26 20:10:04

SN1 on the move! Next step (27.2) is supposed to be pressure-testing...

Here's hoping!

https://www.youtube.com/watch?v=SgFDzmI5_zc

SpaceNut · 2020-02-26 20:36:49

The protype tank of sn1 was the one that blew 3 months ago and the followup is now deemed a production model of the real deal.
It was Feb 10th that starship was being worked by Elon Musk working at night, shares Starship SN1 progress from Boca Chica to keep the timeline for the testing of the new tank.

Starship SN1 will be the first fully-assembled test flight vehicle that will perform a 20 kilometer test flight in the coming months, the first flight could occur as early as March. Musk previously said SpaceX teams could build up to 20 Starship prototypes this year, each featuring slight changes to test out during flight.
The company has been testing stainless-steel propellant tanks to test their weld strength. On January 30, teams conducted a cryogenic pressure test on a propellant dome tank, it reached an internal pressure of 8.5 bar, or about 8.5 times the pressure of Earth's atmosphere at sea level.
The tank needed to withstand a pressure of at least 6 bar for an orbital flight without humans onboard. SpaceX aimed to increase the bar strength to ensure the craft ends up being safe for crewed flights, which is great progress towards the development of Starship SN1.

The distructive testing can lead to tanks that will fail as the test needs to view the level of damaged under the stress test level which are not distructive.

SpaceNut · 2020-02-26 22:39:18

Pretty ugly ship all dented and no protective underbelly for re-emtry back to earth...

PicsArt_02-13-08.06.53_1000x.jpg?v=1581646110

SpaceX is making rapid progress with the construction of their first stainless-steel flight vehicle - Starship SN1, at their South Texas assembly facility. The vehicle's first test flight will take place sometime after March 16, it will fly 20 kilometers above Boca Chica Beach.

louis · 2020-02-27 15:49:59

No humans will be hurt in the next testing...so what's your worry?

SpaceNut wrote:

The protype tank of sn1 was the one that blew 3 months ago and the followup is now deemed a production model of the real deal.
It was Feb 10th that starship was being worked by Elon Musk working at night, shares Starship SN1 progress from Boca Chica to keep the timeline for the testing of the new tank.
Starship SN1 will be the first fully-assembled test flight vehicle that will perform a 20 kilometer test flight in the coming months, the first flight could occur as early as March. Musk previously said SpaceX teams could build up to 20 Starship prototypes this year, each featuring slight changes to test out during flight.
The company has been testing stainless-steel propellant tanks to test their weld strength. On January 30, teams conducted a cryogenic pressure test on a propellant dome tank, it reached an internal pressure of 8.5 bar, or about 8.5 times the pressure of Earth's atmosphere at sea level.
The tank needed to withstand a pressure of at least 6 bar for an orbital flight without humans onboard. SpaceX aimed to increase the bar strength to ensure the craft ends up being safe for crewed flights, which is great progress towards the development of Starship SN1.
The distructive testing can lead to tanks that will fail as the test needs to view the level of damaged under the stress test level which are not distructive.

SpaceNut · 2020-02-27 18:20:19

Musk does think that its going to take 20 more tries to get it right but with this testing method its a good question as to whether its will be a good tank or not when you are pushing it to stress levels without any inspection to prove that it was not damaged. The point is you design it for 10 Bar and test at 8.5 bar to garantee that 6 bar will not fail.

louis · 2020-02-27 20:38:35

I thought 8.5 was the industry standard...

SpaceNut wrote:

Musk does think that its going to take 20 more tries to get it right but with this testing method its a good question as to whether its will be a good tank or not when you are pushing it to stress levels without any inspection to prove that it was not damaged. The point is you design it for 10 Bar and test at 8.5 bar to garantee that 6 bar will not fail.

louis · 2020-02-29 07:18:16

Oh dear - screw up!!

https://www.youtube.com/watch?v=sYeVnGL7fgw

Latest failed pressure test...looks like this is going to take longer than we would hope...

I did see (I think it was in a SpaceXCentric video) that Musk had tweeted that they had been using the wrong welding settings which was why they had had problems with the welding...seems a rather basic error but might explain this latest failure...OK on to the SN2 it would seem. I think that was being readied for a raptor engine test but does that now have to be preceded by a pressure test?

GW Johnson · 2020-02-29 10:14:31

They REALLY need to consult some real experienced experts in cryo pressure vessel design!

Welds are nearly ALWAYS where any pressure vessel fails, because (1) most welds are inherently far weaker than the surrounding parent metal, and (2) the amount of that weakness is inherently variable and only predictable statistically, from a LOT of tests.

Just because the pressures they need are low, does NOT justify not doing proper pressure vessel design. 6-10 bar is trivial compared to what I routinely dealt with in solid rocket work. Most of those motors operated in the 1000-2000 psi range (69-138 bar), and some as high as 4000 psi (276 bar). We built these by the hundreds of thousands, and every single one of them had to work. If you don't want to pressure-test every single one of them, then you do your stats to the 1-in-a-million failure level, even though the contract may only say 1-in-a-thousand. It'll bite you in very expensive ways that put you out of business, if you don't do that right.

There was temperature-induced material weakness at both ends of the scale. Soaked hot (145 to 165 F), basic material strength is drastically reduced, and elongation is the same or maybe slightly higher. While soaked out cold (-65F), strength might be a little bit higher, but elongation is drastically reduced to just about zero, making behavior very brittle. Any little disturbance, even just a really loud noise, and "kaboom".

At cryogenic temperatures, most metals are more brittle than thin-wall glass. 300 series stainless still has some elongation even at liquid hydrogen temperatures, AND we have many decades experience using it for such applications, which is PRECISELY why it is the material of choice for cryo pressure tanks in the liquified gas industry. In great big thick plates. NOT thin sheet.

But, the weakness is always the welds. The only welding techniques we had in the solid motor case business that came close to full parent-metal strength was electron-beam welding in vacuum. That was VERY expensive, and required full QC radiographic inspection of every single weld; couldn't just rely on the stats. Very expensive indeed.

If they are stick-welding this thing out in the open the way I think they are, then the weld efficiency strength knockdown factor they should be using is AT LEAST factor 2 reduction. I'd bet real money they are NOT using that drastic a knockdown factor in their designs.

Now, if they are taking the other tack and just blowing up tanks to experimentally determine where failure occurs, then they haven't built and blown up near enough tanks to establish the statistics. That takes hundreds of each separate design.

Now, for the tank domes, I see they are welding multiple thin plates together in shapes that are closer to conical than round. What horseshit! That structure would be far more reliably made by shear-spinning the rounded dome from one single very large plate, and trimming the periphery to shape.

Similarly, instead of welding a lot of small plates together to make the cylindrical portion of the tank, far better reliability can be had by rolling much larger plates to the required curvature, and then joining them with far fewer welds.

If you want to save weight by using plate thickness sized by pressure, then locally the thicknesses where welds are made need to be twice that. You don't get that as plate or sheet rolled from the mill, you have to special-make it with thin bulk and thicker edges. NOT cheap.

There can be nothing about such processes that can ever be cheap, unless you just use twice or more the hoop-stress-sized thickness you need, and let it be heavy. Not something you can do for a low inert mass fraction rocket vehicle.

Them's just the ugly little facts of life.

GW

Last edited by GW Johnson (2020-02-29 10:21:07)

louis · 2020-02-29 13:02:57

Elon needs you as a consultant GW!

GW Johnson wrote:

They REALLY need to consult some real experienced experts in cryo pressure vessel design!
Welds are nearly ALWAYS where any pressure vessel fails, because (1) most welds are inherently far weaker than the surrounding parent metal, and (2) the amount of that weakness is inherently variable and only predictable statistically, from a LOT of tests.
Just because the pressures they need are low, does NOT justify not doing proper pressure vessel design. 6-10 bar is trivial compared to what I routinely dealt with in solid rocket work. Most of those motors operated in the 1000-2000 psi range (69-138 bar), and some as high as 4000 psi (276 bar). We built these by the hundreds of thousands, and every single one of them had to work. If you don't want to pressure-test every single one of them, then you do your stats to the 1-in-a-million failure level, even though the contract may only say 1-in-a-thousand. It'll bite you in very expensive ways that put you out of business, if you don't do that right.
There was temperature-induced material weakness at both ends of the scale. Soaked hot (145 to 165 F), basic material strength is drastically reduced, and elongation is the same or maybe slightly higher. While soaked out cold (-65F), strength might be a little bit higher, but elongation is drastically reduced to just about zero, making behavior very brittle. Any little disturbance, even just a really loud noise, and "kaboom".
At cryogenic temperatures, most metals are more brittle than thin-wall glass. 300 series stainless still has some elongation even at liquid hydrogen temperatures, AND we have many decades experience using it for such applications, which is PRECISELY why it is the material of choice for cryo pressure tanks in the liquified gas industry. In great big thick plates. NOT thin sheet.
But, the weakness is always the welds. The only welding techniques we had in the solid motor case business that came close to full parent-metal strength was electron-beam welding in vacuum. That was VERY expensive, and required full QC radiographic inspection of every single weld; couldn't just rely on the stats. Very expensive indeed.
If they are stick-welding this thing out in the open the way I think they are, then the weld efficiency strength knockdown factor they should be using is AT LEAST factor 2 reduction. I'd bet real money they are NOT using that drastic a knockdown factor in their designs.
Now, if they are taking the other tack and just blowing up tanks to experimentally determine where failure occurs, then they haven't built and blown up near enough tanks to establish the statistics. That takes hundreds of each separate design.
Now, for the tank domes, I see they are welding multiple thin plates together in shapes that are closer to conical than round. What horseshit! That structure would be far more reliably made by shear-spinning the rounded dome from one single very large plate, and trimming the periphery to shape.
Similarly, instead of welding a lot of small plates together to make the cylindrical portion of the tank, far better reliability can be had by rolling much larger plates to the required curvature, and then joining them with far fewer welds.
If you want to save weight by using plate thickness sized by pressure, then locally the thicknesses where welds are made need to be twice that. You don't get that as plate or sheet rolled from the mill, you have to special-make it with thin bulk and thicker edges. NOT cheap.
There can be nothing about such processes that can ever be cheap, unless you just use twice or more the hoop-stress-sized thickness you need, and let it be heavy. Not something you can do for a low inert mass fraction rocket vehicle.
Them's just the ugly little facts of life.
GW

Oldfart1939 · 2020-02-29 15:19:28

The rupture of the tank on SN 1 was already attributed to using wrong settings on the welder. This test was simply a way of confirming the need for having welding equipment which is properly suited to task! This was undoubtedly a confirmatory test about the weld strength when done at incorrect power settings. Gotta keep on breaking stuff until "it don't break no more!"

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#501 2020-02-06 20:12:26

Re: Starship is Go...

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