Author Topic: The Reaction Engines Skylon Master Thread (5)  (Read 440681 times)

Online john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #260 on: 04/18/2015 08:50 AM »
...and this pretty much puts the last nail in that coffin as it were. You want to use the SABRE cycle you have to use LH2, you don't want to do that then this cycle isn't for you.

So IF the AF wants this for a launch vehicle expect to hear more, if they are looking for anything else it won't be using the SABRE or LH2 :)
With the Delta IV and Centaur the USAF have demonstrated they will tolerate LH2 for certain specific tasks, primarily launch.

Outside that area I don't think they can get their can let go their preconceptions to use it for anything else, and there's simply no way anything like SABRE can work with anything like a normal liquid hydrocarbon.   :(
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Online mhlas7

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #261 on: 04/18/2015 06:15 PM »
Is that Skylon Upper Stage planned to be reusable and return to the Skylon befor reentry or expendable?
It's designed for 10 reuses running on LH2/LO2 through a pair of the SOMA engines. It uses the idea of the duration for an orbit to near GEO being a sub multiple of the period of the Skylon's  orbit (so called "resonant" orbits) so it "falls" back to the Skylon orbit and the Skylon is in place to pick it up than bring it back.
Are there any ballpark numbers for what the payload mass to GEO/GTO might be? I realize that the vehicle and engines are still very theoretical but are we talking about ~6T comsats, ~2T delta class payloads or <1T small sats?

Offline t43562

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #262 on: 04/18/2015 07:48 PM »
Is that Skylon Upper Stage planned to be reusable and return to the Skylon befor reentry or expendable?
It's designed for 10 reuses running on LH2/LO2 through a pair of the SOMA engines. It uses the idea of the duration for an orbit to near GEO being a sub multiple of the period of the Skylon's  orbit (so called "resonant" orbits) so it "falls" back to the Skylon orbit and the Skylon is in place to pick it up than bring it back.
Are there any ballpark numbers for what the payload mass to GEO/GTO might be? I realize that the vehicle and engines are still very theoretical but are we talking about ~6T comsats, ~2T delta class payloads or <1T small sats?

http://forum.nasaspaceflight.com/index.php?topic=33648.msg1207876#msg1207876

About 6.4 tonnes if the SUS is reused, 8 tonnes if it's expended.

Offline Jim

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #263 on: 04/18/2015 07:51 PM »

With the Delta IV and Centaur the USAF have demonstrated they will tolerate LH2 for certain specific tasks, primarily launch.


It is not a "toleration"    Space launch USAF is not the same as the USAF that would want to use the SABRE for other reasons. 

Online john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #264 on: 04/18/2015 08:52 PM »
Are there any ballpark numbers for what the payload mass to GEO/GTO might be? I realize that the vehicle and engines are still very theoretical but are we talking about ~6T comsats, ~2T delta class payloads or <1T small sats?
In addition a SUS can put a satellite with an eletric thruster in a 5900 Km radius orbit above the Van Allan belt so it's not cooked as it reaches orbit. Assuming a 20Kw Hall thruster that would be the eqivalent of close to a 9 tonne sat  to GTO or over 5 1/2 tonnes at GEO.
« Last Edit: 04/18/2015 11:49 PM by john smith 19 »
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Online john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #265 on: 04/18/2015 09:02 PM »
It is not a "toleration"    Space launch USAF is not the same as the USAF that would want to use the SABRE for other reasons.
True.

The "winged" side ofthe USAF seems much less happy about any cryogen that I'm surprised they'd look at SABRE, despite the fact it's looking like the only engine that's coming anywhere close to being built at full size  :(
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline t43562

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #266 on: 04/20/2015 06:50 AM »
On other sites I've seen people asking why it cost so much to develop SABRE compared to rocket engines in other vehicles, specifically the SpaceX ones. I don't actually know if it is all that expensive comparatively but to myself I answer "reusability".

So I was wondering about this kind of thing :-) :
http://aviationweek.com/space/rocket-lab-unveils-battery-powered-turbomachinery

Presumably it doesn't scale or something like that. Nevertheless,  if there was some new risk that offered a possible way to cut the cost of either developing or building SABRE, would it be worth going for?
« Last Edit: 04/20/2015 07:10 AM by t43562 »

Online john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #267 on: 04/20/2015 11:31 AM »
On other sites I've seen people asking why it cost so much to develop SABRE compared to rocket engines in other vehicles, specifically the SpaceX ones. I don't actually know if it is all that expensive comparatively but to myself I answer "reusability".

So I was wondering about this kind of thing :-) :
http://aviationweek.com/space/rocket-lab-unveils-battery-powered-turbomachinery

Presumably it doesn't scale or something like that. Nevertheless,  if there was some new risk that offered a possible way to cut the cost of either developing or building SABRE, would it be worth going for?
It might seem like a reasonable comparison but it's not really a fair one.

In theory both engines are designed for reuse but there the similarity ends.

The gas generator cycle is the most common pumped engine cycle in any propellant combination. There is a lot of prior art on how to build them regarding materials compatibility, design choices and tools  etc.

In contrast there is limited experience of pumped LH2/LO2 engines anywhere with 4 designs in the US (and the only production design dating from the 1960's) with 2 in Europe and 1 (IIRC) in Russia.

SABRE is also roughly 3x bigger than Merline and due to be tested in one of the most populous countries of Europe, making H&S and availability of test stands very big issues.  :(

A fairer comparison would have been the SSME programme. A first of its kind engine using LH2.

I emphasize LH2 because it's much harder to deal with. Typically all LH2 pipework uses welded steel pipes one in side the other, with a vacuum between. "Vacuum Jacket Line" is not cheap and will need to fitted to the SABRE test stands. There are no good ways to simulate LH2's temperature or it's compressibility. AFAIK LH2 is the only common liquid that at "reasonable" pressures (100s, not 1000s of atmospheres) can be compresses by several percent of its normal volume, making pump design especially tricky.  :(

SABRE is a first of its kind design and the only one operating over the M0-M23-M0 speed range.

The SABRE development programme is roughly $300m, I'd guess that's peanuts relative to the inflation adjusted costs of the SSME.

"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline Krevsin

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #268 on: 04/20/2015 12:18 PM »
...and this pretty much puts the last nail in that coffin as it were. You want to use the SABRE cycle you have to use LH2, you don't want to do that then this cycle isn't for you.

So IF the AF wants this for a launch vehicle expect to hear more, if they are looking for anything else it won't be using the SABRE or LH2 :)
With the Delta IV and Centaur the USAF have demonstrated they will tolerate LH2 for certain specific tasks, primarily launch.

Outside that area I don't think they can get their can let go their preconceptions to use it for anything else, and there's simply no way anything like SABRE can work with anything like a normal liquid hydrocarbon.   :(
Could SABRE potentially work with methalox?

Offline RanulfC

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #269 on: 04/20/2015 01:16 PM »
Could SABRE potentially work with methalox?

Not cold enough. See: http://forum.nasaspaceflight.com/index.php?topic=36826.msg1360152#msg1360152

With the Delta IV and Centaur the USAF have demonstrated they will tolerate LH2 for certain specific tasks, primarily launch.

Outside that area I don't think they can get their can let go their preconceptions to use it for anything else, and there's simply no way anything like SABRE can work with anything like a normal liquid hydrocarbon.   :(
It is not a "toleration"    Space launch USAF is not the same as the USAF that would want to use the SABRE for other reasons.
True.

The "winged" side of the USAF seems much less happy about any cryogen that I'm surprised they'd look at SABRE, despite the fact it's looking like the only engine that's coming anywhere close to being built at full size  :(

Actually we've built a few "full-size" engines for various cycles in the past. What we haven't done is fly them :)

Mostly it's an operational thing in that the majority of infrastructure is based on hydrocarbon fuel. If LH2 use and infrastructure were as large there might be less opposition. But given the reduction rather than expansion of LOX operations as the overall infrastructure has grown for civil use I'm pretty sure LH2 by the AF will remain a VERY limited segment of operations :)

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From The Amazing Catstronaut on the Black Arrow LV:
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Offline 93143

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #270 on: 04/20/2015 08:17 PM »
The SABRE development programme is roughly $300m, I'd guess that's peanuts relative to the inflation adjusted costs of the SSME.

That's $360M to get to first working prototype.  Which is about 1/10 of the whole engine development programme, which suggests that their cost estimate includes everything it's supposed to to get the engine into actual production...

EDIT:  Metric vs. Imperial money confusion...
« Last Edit: 05/11/2015 09:28 PM by 93143 »

Offline Citizen Wolf

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #271 on: 05/09/2015 07:00 PM »
Regarding the placement of any future UK spaceport - now that the results of the UK election make the breakup of the UK much more likely (and possibly within 5-10 years), I'd wager that the powers that be will be reluctant to put any money into placing the spaceport in Scotland.
The only thing I can be sure of is that I can't be sure of anything.

Offline A_M_Swallow

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #272 on: 05/10/2015 03:24 AM »
Regarding the placement of any future UK spaceport - now that the results of the UK election make the breakup of the UK much more likely (and possibly within 5-10 years), I'd wager that the powers that be will be reluctant to put any money into placing the spaceport in Scotland.

Possibly, but the British Government is likely to go the other way - use the spaceport as a bribe. Since the Scottish Nationalists are an extreme left wing group (for instance they want Britain's nuclear weapons removing from Scotland) who already control most social spending in Scotland they cannot be bribed with military contracts.

Offline t43562

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #273 on: 05/10/2015 05:28 AM »

Quote from  AM Swallow on: Today at 03:24 AM - sorry I didn't quote this properly when I first wrote it
Quote
Possibly, but the British Government is likely to go the other way - use the spaceport as a bribe. Since the Scottish Nationalists are an extreme left wing group (for instance they want Britain's nuclear weapons removing from Scotland) who already control most social spending in Scotland they cannot be bribed with military contracts.

I don't think the SNP is bribable. Anything you give them, they will present to Scotland as their spoils of war, enhancing their position and increasing the likelihood of them leaving.   It is important for the government to ensure that credit for whatever happens will be attributed to the union.  Something like Skylon might be exceedingly good at that in the way that the aircraft carriers and the type 26 destroyers are.
« Last Edit: 05/10/2015 07:37 AM by t43562 »

Offline A_M_Swallow

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #274 on: 05/10/2015 05:53 AM »
Quote
Possibly, but the British Government is likely to go the other way - use the spaceport as a bribe. Since the Scottish Nationalists are an extreme left wing group (for instance they want Britain's nuclear weapons removing from Scotland) who already control most social spending in Scotland they cannot be bribed with military contracts.

I don't think the SNP is bribable. Anything you give them, they will present to Scotland as their spoils of war, enhancing their position and increasing the likelihood of them leaving.   It is important for the government to ensure that credit for whatever happens will be attributed to the union.  Something like Skylon might be exceedingly good at that in the way that the aircraft carriers and the type 26 destroyers are.

The SNP needs to bring a spoil of war back to Scotland. If they come back with nothing then they will be seen as failures. The Conservative majority is sufficient that the SNP could be ignored/bypassed for the next 3-5 years.

Online john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #275 on: 05/10/2015 08:18 AM »
Regarding the placement of any future UK spaceport - now that the results of the UK election make the breakup of the UK much more likely (and possibly within 5-10 years), I'd wager that the powers that be will be reluctant to put any money into placing the spaceport in Scotland.
Incorrect.

You might like to look at the actual results

http://en.wikipedia.org/wiki/Scottish_independence_referendum,_2014

84% of the eligible electorate voted and the No (to independence) was about 10 percentage points greater than the yes result. For comparison IIRC a better than 50% turnout for the US Presidential election is viewed as good.

This was despite the Scottish Nationalist Party setting the schedule for the vote, the actual question itself and allow 16-18 year olds (statistically likely to vote for the newer idea) to vote.

The leader of the SNP at the time resigned as he had failed, despite every advantage to their campaign. When push came to shove Scots people voted with their heads, not their hearts.

This issue is dead for 1 to 2 generations in Scotland at least.

So IMHO putting a spaceport in Scotland is a pretty safe bet.

BTW on the nuclear issue it's estimated supporting those subs takes about 7000 well paying Scots jobs, and while SNP policy is NIMBY they are pragmatic enough to know that's quite a big black hole to fill.

SABRE/Skylon is designed from the ground up as a civilian space vehicle. Any effort to "weaponize" it would be so complex you'd just as well build your own ICBM.

I think the Scottish government would be happy to welcome REL to the country.
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline Citizen Wolf

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #276 on: 05/10/2015 08:27 PM »
JS19
**This issue is dead for 1 to 2 generations in Scotland at least**

I respect your opinion on matters space-related, but your analysis here is out of step with most political analysts on this point. England has moved to the right. Despite their single seat, UKIP had a lot of support in the election, as judged by their percentage share of the vote. There will be a referendum on the EU in 2 years. If England votes to leave, the UK will break up because the Scots want to stay in the EU.

Even aside from the referendum on the EU, Scottish and English sentiments have diverged in recent years, particularly since the Thatcher years. Cameron's comments subsequent to the Scottish referendum last year have left many Scottish who voted to stay in the union feeling that they were shafted. For unionists, the best likely outcome is now some sort of federal union, but I would not bet against it going further and a fully independent Scotland emerging in the near future.

It is that uncertainty that will make those in power (England) very reluctant to place such a strategically important infrastructure project as the spaceport in an area that they may not have control of in 10 years.

**I think the Scottish government would be happy to welcome REL to the country.**

I certainly agree with you here, but it won't be a decision left to the parliament in Scotland. This decision will be made in London.
The only thing I can be sure of is that I can't be sure of anything.

Online john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #277 on: 05/11/2015 12:07 PM »
JS19
**This issue is dead for 1 to 2 generations in Scotland at least**

I respect your opinion on matters space-related,
That's very flattering. I'll try to continue to live up to your expectations.   :)
Quote
but your analysis here is out of step with most political analysts on this point. England has moved to the right. Despite their single seat, UKIP had a lot of support in the election, as judged by their percentage share of the vote. There will be a referendum on the EU in 2 years. If England votes to leave, the UK will break up because the Scots want to stay in the EU.
It's my view people who want to break some stuff up tend to want to break all stuff up. IOW If you liked the idea of the UK leaving Europe you like the idea of Scotland leaving the UK.

Except when the Scots were given the opportunity more than 84% turned out and it was roughly 11 to 8 against leaving.

http://en.wikipedia.org/wiki/Scottish_independence_referendum,_2014

Looking at UKIP
http://www.bbc.co.uk/news/election/2015/results

People were predicting a)A hung House of Commons and b) UKIP to win 2 seats, including their Leader becoming an MP.

But when push came to shove 1 candidate (not the leader) got elected.  So they delivered 50% of their expected performance.  The Liberal Democrats were destroyed but they still managed to retain 8 seats. Even the political wing of a disbanded terrorist group has more seats in the House of Commons than UKIP.

This referendum (assuming it happens) is about Prime Minister Cameron retaining the support of a group of his (mostly) non ministerial MP's who remain obsessed with the idea of leaving the EU.

UKIP is to UK politics what Fox News is to CNN. You may be entertained by it but actually there's not that much there and they both have definite agendas, which you should be very conscious of.  :(

Quote
Even aside from the referendum on the EU, Scottish and English sentiments have diverged in recent years, particularly since the Thatcher years. Cameron's comments subsequent to the Scottish referendum last year have left many Scottish who voted to stay in the union feeling that they were shafted. For unionists, the best likely outcome is now some sort of federal union, but I would not bet against it going further and a fully independent Scotland emerging in the near future.
Either preliminary work will go ahead regardless in pursuit of this policy directive or all work will be delayed pending the referendum outcome. As it is a stated goal of the BSA to increase UK experience and skill in space engineering the simple option is to go ahead

If the result is for leaving the EU and if Scotland requests a 2nd independence referendum (BTW the Houses of Parliament are the body that granted the right to hold a referendum in the first place) then that will require review. That's 2 big "if's" in a row after the big one of wheather there will be a referendum at all.

It looks like Cameron said he will, but words can be ambiguous.  :(
Quote
It is that uncertainty that will make those in power (England) very reluctant to place such a strategically important infrastructure project as the spaceport in an area that they may not have control of in 10 years.
Unless they are confident enough that the bulk of the British people will vote to stay that they are not worried.  :)
Quote
**I think the Scottish government would be happy to welcome REL to the country.**

I certainly agree with you here, but it won't be a decision left to the parliament in Scotland. This decision will be made in London.
No. It will be made in Culham.

REL is a private company. The UK Govt is a minority investor and AFAIK have no management input.

They could just as easily go to Toulouse instead.

While it could be said this is loosely relevant to SABRE/Skylons future I think it's going quite far OT.

From REL's perspective their next big events (I think) will be getting the test stand for SABRE ready and of course getting the full size flight configuration (although not I suspect flight weight) engine ready for it.
« Last Edit: 05/11/2015 12:18 PM by john smith 19 »
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline Citizen Wolf

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #278 on: 05/11/2015 02:13 PM »
Regarding the likelihood of Scotland staying in the UK, we are in disagreement. As you say it's off-topic for this thread so we'd probably best not thrash it out here.

JS19
**No. It will be made in Culham.
REL is a private company. The UK Govt is a minority investor and AFAIK have no management input.**

Yes, of course, decisions for REL will be made by REL. However the placement of the spaceport is a decision that will be made in London. REL will go wherever the spaceport goes (not Scotland IMO: See above).

The only thing I can be sure of is that I can't be sure of anything.

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #279 on: 05/11/2015 03:08 PM »
Hmm I am surprised that you guys are thinking that local politics could have such an effect on the development of Skylon. In fact I would suggest not going down that road here again or I might need to start to intervene.  ;)
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