Blue Origin Thread (merged)

[YNM]

On 9/24/2016 at 7:32 AM, DerekL1963 said:

It wasn't "just broke by cryogenics" - it was blown apart by a near explosive event.  I don't think there's ever been, or ever will be, a flight worthy booster than can withstand severe overpressure of it's tankage.  

Hmm, yes. Hope they can salvage any form of pre-explosion deformation data from the fireball ruins, if there's any. Or any detachment data.

 

EDIT :

So, yet another helium tank rupture ? So one wasn't enough, or they won't dipose the ones made already ? (and yes, sorry, I have no idea whether can steel really go crack with cold)

Edited September 25, 2016 by YNM

[DerekL1963]

 

On 9/23/2016 at 5:37 PM, YNM said:

So, yet another helium tank rupture ? So one wasn't enough, or they won't dipose the ones made already ? (and yes, sorry, I have no idea whether can steel really go crack with cold)

This is their first tank rupture, the previous failure was in the structure restraining the tanks.  (The structure failed and the tank tore loose from it's piping.)  The tanks aren't steel, they're COPV

[Kryten]

It was a helium system rupture, but we don't have enough info to say it was definitely a COPV; failure in the plumbing close to one could have much the same effect.

 

In other news;

 

Edited September 26, 2016 by Kryten

[Nibb31]

Judging from the height of the handrailings, it looks smaller than Merlin.

[Kryten]

Quote

Elon Musk‏ @elonmusk

Production Raptor goal is specific impulse of 382 seconds and thrust of 3 MN (~310 metric tons) at 300 bar

Even with FFSC and that chamber pressure, you're not going to get that thrust out of an engine smaller than Merlin. It looks like it's a combustion chamber with no real nozzle yet, that would throw off apparent size quite a bit.

Edited September 26, 2016 by Kryten

[CatastrophicFailure]

22 minutes ago, Kryten said:

It was a helium system rupture, but we don't have enough info to say it was definitely a COPV; failure in the plumbing close to one could have much the same effect.

 

In other news;

 

Well, that's a welcome spot of good news. 

1 minute ago, Kryten said:

Even with FFSC and that chamber pressure, you're not going to get that thrust out of an engine smaller than Merlin. It looks like it's a combustion chamber with no real nozzle yet, that would throw off apparent size quite a bit.

Can... can they even DO that?

[Kryten]

Either that or it's a subscale test model.

[Frozen_Heart]

1 hour ago, Kryten said:

Either that or it's a subscale test model.

There have been rumours about a smaller Raptor for testing and use on the Falcon upper stage.

 

Edit: Turns out the vacuum version will have a nozzle diameter is 4.3m. Much bigger than the Merlin then. 

Edited September 26, 2016 by Frozen_Heart

[Streetwind]

Gwynne Shotwell confirmed (while talking about the first fully assembled Raptor being shipped to McGregor, a month ago or so) that it was indeed a subscale model.

Note: "subscale" can mean a great many things. SpaceX has not had a firm thrust target for the Raptor from the get-go, but rather aimed to pick whatever thrust they would get at the point where the engine TWR is optimized. So they tried stuff anywhere from twice a Merlin's thrust, to something more powerful than a F1. It is possible that this "subscale" model is still the real deal - just not at the 3 MN thrust level that Elon Musk just announced they settled on. Maybe this one only does 2 MN.

It's also possible that this is an intentionally downscaled engineering article, of course. It just doesn't have to be. SpaceX has unfortunately not been unambiguous here.

Edited September 26, 2016 by Streetwind

[Kryten]

Fins look to be smaller than in the original reveal.

[_Augustus_]

This thing is YUUGE! The engine bell is bigger than the F1.

https://twitter.com/elonmusk/status/780275236922994688/photo/1

[Kobymaru]

I am very, very hyped for the IAC 2016 talk.

[RedKraken]

I can't wait to see this thing fly. 

2017 looks like being a very exciting year for rocket-heads.

4 minutes ago, Kobymaru said:

I am very, very hyped for the IAC 2016 talk.

Same

[PB666]

The engine has a space ISP of 368, prolly because its methane based and not hydrogen, but I was just wondering how the thrust to weight ratio compares between

the Merlin 1d vacuum and the Raptor engine. They say it has many times the thrust, but do you really need that much thrust landing on Mars. Once the rocket is in LEO it can basically use a smaller engine to kick several times from perigee until it has enough velocity to punch into a transfer orbit. Isn't the whole idea about transfer engines is to keep them as small, lightweight as possible relative to the fuel payload.

Obviously SX is working on a recapture system for O2 and CH4 in order to stabilize the fuel for post transfer circularization and landing. If such is the case then I am wondering why not go for hydrogen.

[RedKraken]

Elon tweeted the vacuum raptor bell is about 14ft (4.2m).   3MN,  380s is a nice surprise.

Ive seen suggestions the atmospheric raptor bell would be about 5ft (1.5m)... 2.5MN, 320s reasonable?

So

Raptor (atmos) 1.5m, 2.5MN, 320s at sea level up to 2.8MN, 360s (sorry lots of guessing here).

Raptor (vacuum)  4.2m, 3MN, 380s (all from Elons tweet)

SSME is 2.4m, 1.8MN, 366s up to 2.3MN, 452s, 3500kg.

F1 was 3.7m, 6.8MN, 263s, 8400kg. 

M1 hydrolox design was 4.2m, 3.8MN, 310s up to 5.3M 428s , 9000kg.

7 hours ago, PB666 said:

the whole idea about transfer engines is to keep them as small, lightweight as possible

i am very interested in the engine masses.....anyone want to have a guess ???

Edited September 26, 2016 by RedKraken

[RedKraken]

1 hour ago, PB666 said:

why not go for hydrogen

i'm guessing boiloff over 5-6 month transfer is a big problem for propulsive landing. Embrittlement problems with materials it touches. Hydrogen tanks are massive. 

i think the fluid management guys have demonstrated ~2% loss per month, but nothing has flown. 

Centaur upper stage is only good for "a dozen hours".

ACES upper due 2020 is supposed to be good for multiple days. Not very encouraging.

They may actually take H2 for ISRU on the martian surface. Will cut into payload, but reduces isru complexity and risk. Ice mining+hydrolysis versus 30t of pure H2 ready loaded in the ISRU plant. You get boiloff over the 2yr mission so you take extra to cover.

Rob Zubrins RWGS-Eth design gets 30:1 leverage H2 to methalox at very reasonable power (225kW) and weight (1000kg). Makes 1000kg of fuel a day. 600 days surface mission gives you 600t of fuel to get your 110t MCT home. Bob's your uncle.

http://www.pioneerastro.com/Team/RZubrin/Mars_In-Situ_Resource_Utilization_Based_on_the_Reverse_Water_Gas_Shift_Experiments_and_Mission_Applications.pdf

This awesome paper was from 1997. I dont know what the latest and greatest isru stuff is. 

1 hour ago, PB666 said:

post transfer circularization

?? I think they are going direct to surface. aerobraking plus propulsive landing. No circ burn at all.

Edited September 26, 2016 by RedKraken

[Jovus]

6 hours ago, PB666 said:

Obviously SX is working on a recapture system for O2 and CH4 in order to stabilize the fuel for post transfer circularization and landing. If such is the case then I am wondering why not go for hydrogen.

I'm guessing here.

First, there are the cryogenic constraints. Refrigerating CH4 and LOX for the Earth-Mars and Mars-Earth transfer is easier than refrigerating H2 and causes less embrittlement because CH4 is less likely to slip into metallic matrices.

Second, and much less important, simple tankage architecture may be easier with CH4, because the tanks will be smaller.

Most importantly, I should think, is that it's a lot easier to make CH4 out of readily-available Martian materials. You just need to bring a bit of hydrogen, though nowhere near as much as you'd need if you were going to burn it directly. Contrariwise, refueling with H2 at Mars is hard, perhaps impossible.

[Nothalogh]

8 hours ago, _Augustus_ said:

This thing is YUUGE! The engine bell is bigger than the F1.

The F-1 was a low atmo engine, this is a vac optimized transfer engine

[RedKraken]

How do you protect those huge fragile 4m bells from mars entry and earth EDL?

I can only think of engine dugouts thru the heat shield that have armoured caps like missile silos.

You could have your heatshield at the opposite end from your motors....but the flip-around acrobatics and pumping fuel to change COM feels like a bad thing to be doing during EDL.

[Nothalogh]

5 minutes ago, RedKraken said:

How do you protect those huge fragile 4m bells from mars entry and earth EDL?

I can only think of engine dugouts thru the heat shield that have armoured caps like missile silos.

You could have your heatshield at the opposite end from your motors....but the flip-around acrobatics and pumping fuel to change COM feels like a bad thing to be doing during EDL.

Likely the Transplanetary vehicle will not enter either atmosphere

[legoclone09]

I can't wait for tomorrow!

Chugga chugga! All aboard the hype train!

[RedKraken]

8 minutes ago, Nothalogh said:

Likely the Transplanetary vehicle will not enter either atmosphere

Ok we are talking two different mission architectures here..

Directs-to-surface verses the orbital rv.

It will be fascinating to find out... not long to go now.... 18hrs

[kerbiloid]

If not ISRU, why methane? Kerosene is not volatile, needs no cryogenics, its tanks are lighter, ISP isn't much less.
If ISRU, how they would lift tens if not hundreds tons of liquid methane from Mars to the ship orbit. Hard to imagine a lander with multi-use 4 meter nozzles.

Edited September 27, 2016 by kerbiloid

[hms_warrior]

We will know for sure tomorrow, but what i have read so far they will lift the methane the same way we lift everything: with rockets!^^ Basicly the Ship that lands on Mars has enough delta V that, once refilled via ISRU it can do single-stage-from-Mars-to-earth (SSMTE?^^)

[lugge]

So, is there a stream for the talk? When it is scheduled?