SpaceX rockets and launches

[weltweit]

If only there was some way of interconnecting a global network of information stores, and - oh, I don't know - in some way indexing them, so that it was possible to type, say, "Staged combustion cycle engine" into a web page, and find some answers...LMGTFY

People like to explain things that they know about, and it is a compliment that I am asking them about something they obviously know about.

If every post that could be discovered on duck duck go was not made, there would be far fewer discussions on urban.

 

[existentialist]

People like to explain things that they know about, and it is a compliment that I am asking them about something they obviously know about.

If every post that could be discovered on duck duck go was not made, there would be far fewer discussions on urban.

Public service, innit?

 

[Crispy]

FFSC:

Rocket engines need pumps to push all the propellant/oxidiser into the combustion chamber. Very powerful, very high flow rate pumps. They burn a bit of the prop/oxy in turbines to power these pumps. There are various strategies for these. Do they run fuel rich or oxidiser rich? What do you do with the exhaust?

The Merlin engine on the falcon 9, for example, is a simple gas generator. There's one turbine, running on small tap-off lines from the main prop/oxy feedlines, driving both pumps. The exhaust is dumped into the nozzle, downstream of the combustion chamber.

Raptor has two turbines, one oxy rich, one fuel rich, through which the entirity of the fluids pass. High volumes through the turbines means lower speeds, and thus less wear and rear. Then the hot exhaust gases are combined in the combustion chamber.

It's very efficient and very amenable to reusability. Very hard to do though. Lots of variables to balance, very tricky metallurgy for the oxy-rich turbine (superhot oxygen will burn almost anything) and you can't test parts of it independently. You can run the power pack of a gas generator engine on its own. A full flow staged combustion engine is all or nothing.

This is a great video on why Raptor is so important:

 

[a_chap]

If you want to get a better idea of what a gas generator does, try these NASA videos:

A bit of info about the gas generator they're testing:



Two views of the test:





Now imagine all that energy being used purely to drive a turbine to pump propellants into one F-1 engine...

Note: the gas generator runs very fuel-rich, hence all the thick black smoke. This "cooler" exhaust gas was then fed into the nozzle extension to create a protective layer from the hotter rocket exhaust. And this is why there's a darker area immediately below the F-1 engine when the Saturn V takes off.

 

[a_chap]

Oh, a statistic popped into my head.

The Bloodhound SSC was going to use a Jaguar V8 just to power the oxidiser pump...

The 1000mph Bloodhound SSC Will Use A 542bhp Jaguar V8 Just To Power A Fuel Pump

As a comparison the gas generator/turbine powering the propellant pump for a single F-1 engine was 50,000 horsepower

 

[a_chap]

Here's a rather special video: First stage launch to landing.

 

[editor]

Love the tech

 

[MikeMcc]

What is that and how does it work?

Scott Manley does a very good (and short) presentation on the different engine cycles with the pros and cons for each:

 

[Crispy]

Starship Mk1 taking shape in Texas. This is just the bottom half; there's a top part, with fins of its own near the nosecone. That should get stacked later this week before a big presentation from Musk on Saturday. It's hard to believe, but they say this thing will be making flights into space this year.

And then there's the Super Heavy first stage booster which is just as big, so the whole rocket is 4 times as tall. Red rectangle is the part in the photo above:

 

[editor]

Starship Mk1 taking shape in Texas. This is just the bottom half; there's a top part, with fins of its own near the nosecone. That should get stacked later this week before a big presentation from Musk on Saturday. It's hard to believe, but they say this thing will be making flights into space this year.

And then there's the Super Heavy first stage booster which is just as big, so the whole rocket is 4 times as tall. Red rectangle is the part in the photo above:

View attachment 184866

Loving the sci-fi comic book look!

 

[Crispy]

To give an idea of scale, the comnplete stack at 118m is about as high as Millbank Tower or Centrepoint.

 

[Crispy]

If you're feeling particularly spoddy, you can watch them stack the complete Starship prototype live:

 

[Crispy]

Like, right now

 

[Crispy]

 

[editor]

It still doesn't look quite real to me. It looks like some kid has made an oversized Dan Dare spaceship in their garden!

 

[a_chap]

I know everyone's supposed to think it looks amazing but I think it's hideous.

It reminds me too much of the Atlas rocket which, although it was used to launch Mercury capsules, was primarily intended to deliver hydrogen bombs.

 

[weltweit]

It still doesn't look quite real to me. It looks like some kid has made an oversized Dan Dare spaceship in their garden!

Exactly what I was going to say.
To me it looks like a full scale model, surely it can't be real with all those joints and patches of metal in the body. I don't think it is a real rocket at all.

 

[Crispy]

Yearly Starship update from Musk tonight, going into all the detail of the new Starship design, Raptor engine, Super Heavy booster, Mars plans etc. If you can stand to hear him talk (he's a terrible speaker, also he's Elon Musk) you can watch live here, at 1am UK time.



Q&A should be worth hanging around for as this is pretty much a spaceflight-reporters-only media event.

 

[2hats]

Anyone with a clear sky in the southern UK in about 9 minutes might be treated to the Dragon and upper stage passing high in the SW from W to SE at around 1750UT (will enter eclipse about half way through the pass). Look out for interesting venting events.

PS good ISS passes too at the moment as a consequence (check eg heavens above).

 

[a_chap]

If you can stand to hear him talk (he's a terrible speaker... ) [/MEDIA]

I cannot. Everything about listening to him grates with me.

Anyone with a clear sky in the southern UK ... might be treated to the Dragon and upper stage passing high in the SW from W to SE ... Look out for interesting venting events.

Anyone with a clear sky in the southern UK in about 9 minutes might be treated to...

 

[2hats]

Sorry. I'll try to give more warning next time. Only just occurred to me. Lot of cloud around anyway it seems.

 

[editor]

Whoosh!

 

[a_chap]

A successful launch abort test!

 

[Detroit City]

View attachment 196124

A successful launch abort test!

WTF?

 

[a_chap]

WTF?

Is that a serious question?

 

[Detroit City]

Is that a serious question?

No I was just surprised that they would waste an entire vehicle

 

[HAL9000]

 

[2hats]

No I was just surprised that they would waste an entire vehicle

Not much choice if you want to convincingly demonstrate emergency escape during the most critical ascent phase through the upper troposphere. The F9 first and second stages were fully fuelled and the first stage wasn't going to survive re-orientation/have sufficient altitude/speed/time to fly back. The second stage fell intact to the ocean surface where it exploded on impact (it didn't have a motor, was just fitted up with an appropriate ballast weight).

 

[a_chap]

No I was just surprised that they would waste an entire vehicle

Wasted? It wasn't wasted!

Good grief.

 

[StoneRoad]

Watched the live feed for this, the control room watchers (?) were quite noisy each time there was a success point.

I stopped watching (as we lost the feed) just after they said the dragon capsule had splashed down and of the fast boats was heading over to it ...