SpaceX META Thread

In the Aircraft Projects subforum, meta-threads are very successful. The intention is to keek information in a single spot that is easy to find and thus facilitate discussion. Not every minor event warrants its own thread after all.

SpaceX needs no introduction. Everything related to Falcons, Starships and Starlinks has a home here.


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Starhsip SN1 loss

So in related news, SpaceX lost Starship prototype SN1 tank stack last night. It blew up rather spectacularly during a pressure test of the LOX tank.
Of course, there's a video: www.youtube.com...

Obviously this wasn' intended at all. SN1 was supposed to have a static fire test soon and maybe even fly at one point.

The next prototype, SN2 is already being build though and the SN1 engine section wasn't attached to the tank section when it blew.
So testing should continue with only minor delays.

a reply to: mightmight

My goodness! Tragic but I guess this is what you need to improve, no excuses for Spacex though. Would've thought the pressure test, with all the tech, would be fine.

Cheers,

Bally

a reply to: bally001

Yeah well, they test to fail but at one point or another, they need to ask themselves if the conditions they are building these prototypes in are adequate. We obviously don't have enough information about what the actual issues are, but building those tanks and pressure vessels shouldn't be that hard and actually pretty easy compared to what will come further down the road.

Whether it's the compressed time table, working conditions, the experience level of the construction crews, lack of proper funding or underlying engineering issues - they are not getting what they from these prototyping efforts atm.
I guess they approached the Falcon 1 development in a similar way, but I do question the rationale of rushing into building prototype after prototype when so little is actually nailed down.

So according to Musk, they lost SN1 basically due to a welding issue with the thrust plate the engine would push against below the LOX tank. They're gonna test it thoroughly before they try to testfire SN2.

It's really annoying seeing all the articles about it exploding though.

a reply to: Zaphod58

well technically the methane tank did explode when it hit the ground

lengthy, in depth article about what they are doing at Boca Chica atm
well worth a read

Inside Elon Musk’s plan to build one Starship a week—and settle Mars
arstechnica.com...

Starlink launch 4 booster loss

The booster diverted itself to a water landing due to unexpected wind conditions during landing.
twitter.com...


CRS-20 launch

No big news, but the last Dragon CRS vehicle is currently on the way to the ISS. It is the third launch of this spacecraft to the space station and the second launch of the Falcon booster. The booster landed successfully at the Cape.

The night launch produced some breathtaking footage, check this out:
twitter.com...
twitter.com...

Starlink 5 launch abort

Starlink 5 experienced a launch abort at T+00:00 due to an engine data anomaly. The first launch abort since 2016.
They'll probably try again in the coming days.

Starlink 5 booster loss during reentry

more bad news
They successfully launched Starlink 5, but the booster didn't make it back. The feed was lost after the reentry burn. It looked like the booster was sort of wavering and there was also what looked like debris from an engine.

www.youtube.com...
7:50 in

There was also an anomaly with the exhaust bloom just before MECO, hinting at something going wrong with an engine: twitter.com...

This is two destroyed booster in two Starlink flights with the more ambitious flight envelope.

An issue at MECO would be very bad news i think. Losing a booster during reentry is one thing, but a failure during launch will directly impact the upcoming crewed flight to the ISS. I wouldn't bet on it happening anytime soon if an engine failed before MECO.

If only they had that magic technology from 1969.... A shame we destroyed that technology



Soon spaceX will realize the van allen belts are insurpassable, as NASA has already admitted:

a reply to: mightmight

Flight profile flown by Starlink is much more demanding than normal launches

Reentry speeds are much higher placing higher stress than other profiles

SPACE X is probably working on a solution

a reply to: cooperton

And yet, they aren't, and they didn't. NASA was talking about Orion having to be tested going through certain portions of the belts. They're far more computerized than Apollo, which means radiation can affect them much more. The Van Allen Belts are not the uniform, impassable barrier you think and claim. Difficult in places, yes. Impossible, no.

originally posted by: firerescue
Flight profile flown by Starlink is much more demanding than normal launches

Reentry speeds are much higher placing higher stress than other profiles

SPACE X is probably working on a solution

Yes and they changed it only for this mission and the one before.
But the last time the booster aborted intentionally since they had unexpectedly bad winds over the drone ship. A nonissue, just bad luck and maybe pushing the launch a bit.
This time it looks like something went wrong just before main engine cut off during ascent. This would directly impact future launches, especially the upcoming crewed mission

Musk has confirmed an early engine shutdown.
twitter.com...
A bit too cavalier for my taste, yes the vehicle has flown a couple of times before and the crewed mission will get a new booster anyway, but they need to prioritize recovery over launch cadence.

originally posted by: Zaphod58
a reply to: cooperton

And yet, they aren't, and they didn't.

Those are official NASA scientists saying that.

NASA was talking about Orion having to be tested going through certain portions of the belts. They're far more computerized than Apollo, which means radiation can affect them much more. The Van Allen Belts are not the uniform, impassable barrier you think and claim. Difficult in places, yes. Impossible, no.

I'm going off data from temperature determinations for the exosphere and thermosphere. It is a region of about 1700 degrees Fahrenheit that is over 400km deep.



Given 400km (248 miles) of 1700 degree temperatures, I'm not sure how the apollo spacecraft, which is made of aluminum (1200 degree melting point), could have possibly made it through. Rock solid iron meteors (2,800 degree melting point) usually don't make it past this layer, yet they want us to believe an aluminum can made it?

a reply to: cooperton

They're NASA statements taken out of context. Radiation in space is not the same as on earth, so protecting against it is different. Getting through on a trajectory to the moon is fairly simple, but Orion isn't just going to the moon, and isn't just going for short periods, so has to be tested against higher radiation levels. Until it's tested, they don't know if it can go through. They're fairly confident in their models and simulations, but won't be certain until it's in the belts getting hit by the radiation.

As for temperature, you're mistaken. Yes, the temperature is high, but it's not that straightforward. On earth, there's a thick atmosphere to transmit heat through. As the air gets thinner, heat isn't transmitted nearly as efficiently. In a near vacuum heat transmission is vastly different. The temperature shows very high, but if you were able to go out without a space suit, you'd freeze almost instantly. There's almost nothing to transfer the heat through into the craft as it's traveling through.

a reply to: cooperton

The outer shell of the Apollo was made of stainless steel

The interior shell was an aluminum honeycomb structure

As Zap said the while the temperature is high , basically the energy level of the random gas molecules, there is nothing to transfer the energy to other objects

a reply to: Zaphod58
a reply to: firerescue

Most iron meteorites don't make it through the atmosphere, and they're rock solid iron (melting point 2,800), so how could a spaceship with a much thinner outer layer make it? It just doesn't seem right. I'm pretty sure we didn't go to the moon, but I figure Elon will eventually be able to confirm whether or not that's true.

Either way it's exciting - if we faked it, then that means our ideas on what space is will be revolutionized. If we actually did go, then the next frontier awaits as it becomes a privatized venture.

Hopefully They don't go bankrupt before figuring something out.

a reply to: cooperton

Think about it for a second. If heat transfer is dependent on atmosphere thickness, what's going to happen to something coming deeper into the atmosphere. The asteroids don't survive because they're going from where heat isn't transferred well, to where heat is transferred very well, resulting in them getting extremely hot, extremely quickly.

A rocket does the exact opposite. It starts building heat as its climbing, from friction in the atmosphere, but it quickly goes to an area where heat isn't transferred almost at all. That's a great medium to dissipate any heat that built up during launch.

originally posted by: Zaphod58
a reply to: cooperton

Think about it for a second. If heat transfer is dependent on atmosphere thickness, what's going to happen to something coming deeper into the atmosphere. The asteroids don't survive because they're going from where heat isn't transferred well, to where heat is transferred very well, resulting in them getting extremely hot, extremely quickly.

A rocket does the exact opposite. It starts building heat as its climbing, from friction in the atmosphere, but it quickly goes to an area where heat isn't transferred almost at all. That's a great medium to dissipate any heat that built up during launch.

But the lunar module would have had to return to earth through the same path an asteroid would. So that is not an exemption.