Author Topic: The Reaction Engines Skylon Master Thread (5)  (Read 442428 times)

Offline Soundbite

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1060 on: 12/15/2015 04:25 PM »
I don't know if anyone is interested, but there is an article today on MailOnline http://www.dailymail.co.uk/sciencetech/article-3359967/Spaceplanes-vs-super-rockets-Expert-reveals-win-battle-cheap-space.html where a Bristol University academic compares the estimated cost of a Skylon launch with that of reusable versions of Falcon 9 and Falcon Heavy.  He suggests that Skylon could never compete.  What do you all think?

Offline Hankelow8

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1061 on: 12/15/2015 05:29 PM »
I don't know if anyone is interested, but there is an article today on MailOnline http://www.dailymail.co.uk/sciencetech/article-3359967/Spaceplanes-vs-super-rockets-Expert-reveals-win-battle-cheap-space.html where a Bristol University academic compares the estimated cost of a Skylon launch with that of reusable versions of Falcon 9 and Falcon Heavy.  He suggests that Skylon could never compete.  What do you all think?

Looks like the real difference is the cost of liquid hydrogen compared to kerosine, it is massive, lets hope it's not Skylons "Achilles heel".

Offline Hanelyp

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1062 on: 12/15/2015 06:25 PM »
If we can get to the point where the relative cost of LH2 vs. kerosene is a large portion of launch costs, mission accomplished.

Online john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1063 on: 12/15/2015 11:26 PM »
I don't know if anyone is interested, but there is an article today on MailOnline http://www.dailymail.co.uk/sciencetech/article-3359967/Spaceplanes-vs-super-rockets-Expert-reveals-win-battle-cheap-space.html where a Bristol University academic compares the estimated cost of a Skylon launch with that of reusable versions of Falcon 9 and Falcon Heavy.  He suggests that Skylon could never compete.  What do you all think?
Historically propellant costs have been in the noise limit of costing estimates for all LV's
"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 Robotbeat

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1064 on: 12/15/2015 11:41 PM »
I don't know if anyone is interested, but there is an article today on MailOnline http://www.dailymail.co.uk/sciencetech/article-3359967/Spaceplanes-vs-super-rockets-Expert-reveals-win-battle-cheap-space.html where a Bristol University academic compares the estimated cost of a Skylon launch with that of reusable versions of Falcon 9 and Falcon Heavy.  He suggests that Skylon could never compete.  What do you all think?
Historically propellant costs have been in the noise limit of costing estimates for all LV's
In this case, it's really about the development costs, not about the hydrogen costs (although the hydrogen costs do impact development and operations cost, just not for the cost of fuel itself).

In the very long term, with arbitrarily high reuse, then fuel cost matters. But we're not anywhere there, yet.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Online Asteroza

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1065 on: 12/16/2015 03:46 AM »
Uh, how far would it hobble Skylon operators to ban traditional toxic hypergols in payloads? Considering all the moves to electric thrusters as it is, what specific scenarios end up essentially needing hypergolic propellants? The missions that come to mind is any kind of short, high thrust scenario where a solid kick stage is undesirable, so some manned systems perhaps?

Offline tl6973

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1066 on: 12/16/2015 09:12 AM »
Uh, how far would it hobble Skylon operators to ban traditional toxic hypergols in payloads?

As much as it would hobble other operators, I would guess.

None of the skylon architecture uses hypergols (the Skylon Upper Stage has SOMA engines which are LoX/ LH2), so it would be the payload builders that would have to go back to the drawing board.





Offline francesco nicoli

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1067 on: 12/16/2015 10:09 AM »
I don't know if anyone is interested, but there is an article today on MailOnline http://www.dailymail.co.uk/sciencetech/article-3359967/Spaceplanes-vs-super-rockets-Expert-reveals-win-battle-cheap-space.html where a Bristol University academic compares the estimated cost of a Skylon launch with that of reusable versions of Falcon 9 and Falcon Heavy.  He suggests that Skylon could never compete.  What do you all think?
Historically propellant costs have been in the noise limit of costing estimates for all LV's
In this case, it's really about the development costs, not about the hydrogen costs (although the hydrogen costs do impact development and operations cost, just not for the cost of fuel itself).

In the very long term, with arbitrarily high reuse, then fuel cost matters. But we're not anywhere there, yet.

It's about development costs, without computing SpaceX development costs.

sure, guess who wins? :)

Offline Soundbite

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1068 on: 12/16/2015 10:45 AM »
Aviation Week has just announced that Reaction Engines are one of their 4 finalists for their Laureate Awards in their Technology section for 2016 See link on Rocketeers http://rocketeers.co.uk/node/4452.  They are definitely beginning to be noticed State side.

Offline Jim

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1069 on: 12/16/2015 11:36 AM »
Uh, how far would it hobble Skylon operators to ban traditional toxic hypergols in payloads? Considering all the moves to electric thrusters as it is, what specific scenarios end up essentially needing hypergolic propellants? The missions that come to mind is any kind of short, high thrust scenario where a solid kick stage is undesirable, so some manned systems perhaps?

There isn't "all the moves", it has only been GEO comsats that have done it.  The issue is for attitude control and not orbit changing.  Most spacecraft need thrusters with more power than electric ones.
« Last Edit: 12/16/2015 11:37 AM by Jim »

Offline pippin

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1070 on: 12/16/2015 11:39 AM »


It's about development costs, without computing SpaceX development costs.

sure, guess who wins? :)

Well, this is where all the nonsense about the supposed advantages of separating operator and manufacturer business cases starts to hit you back...

This is not including development costs but costs of one LV.

Offline francesco nicoli

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1071 on: 12/16/2015 12:15 PM »


It's about development costs, without computing SpaceX development costs.

sure, guess who wins? :)

Well, this is where all the nonsense about the supposed advantages of separating operator and manufacturer business cases starts to hit you back...

This is not including development costs but costs of one LV.

Fair enough, but the study compares one LV with 200 flights capability with one with 10, without computing the capital cost you have to recur each10 times for Falcon. Moreover, there is no Fully reusable Falcon yet announced....

Offline pippin

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1072 on: 12/16/2015 12:48 PM »
If the cost of the Falcon is total cost then you don't need to calculate any additional capital cost. And anything else would be apples to oranges because the cost of Skylon IS total cost.
Both need to add operations which he argues is more expensive for Skylon which is probably correct.

So it all boils down to interest rates and flight rates...

Offline tl6973

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1073 on: 12/16/2015 02:24 PM »
I know this is probably impossible to find, but does anyone know what the ground operations costs of something like
the SR71 or the B2 Spirit stealth bomber are like?

Might those be reasonable analogues to the operating costs for Skylon?

I'm sure there are many reasons why not, just want to have a think about required number of personnel, handling facility sizes etc.

Offline francesco nicoli

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1074 on: 12/16/2015 03:05 PM »
If the cost of the Falcon is total cost then you don't need to calculate any additional capital cost. And anything else would be apples to oranges because the cost of Skylon IS total cost.
Both need to add operations which he argues is more expensive for Skylon which is probably correct.

So it all boils down to interest rates and flight rates...

They compute only a one-off count, not a recylce of the acquisition each 10 launches. Basically, it is like buying one skylon and using it 200 times, or buying a falcon 9 and using it 200 times. which is wrong.

Also, keep in mind that a Skylon should have an oeprational life of minimum 30 years. Which means around 6 flights per year, to have the minimu price of  millions. at higher prices you need much less flights.
« Last Edit: 12/16/2015 03:05 PM by francesco nicoli »

Offline pippin

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1075 on: 12/16/2015 03:28 PM »

If the cost of the Falcon is total cost then you don't need to calculate any additional capital cost. And anything else would be apples to oranges because the cost of Skylon IS total cost.
Both need to add operations which he argues is more expensive for Skylon which is probably correct.

So it all boils down to interest rates and flight rates...

They compute only a one-off count, not a recylce of the acquisition each 10 launches. Basically, it is like buying one skylon and using it 200 times, or buying a falcon 9 and using it 200 times. which is wrong.

Also, keep in mind that a Skylon should have an oeprational life of minimum 30 years. Which means around 6 flights per year, to have the minimu price of  millions. at higher prices you need much less flights.

No, that's not true. They use a different scale for the amortization. It's confusing but correct, they assume to buy 20 Falcons for 200 flights.

Offline francesco nicoli

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1076 on: 12/16/2015 03:48 PM »

If the cost of the Falcon is total cost then you don't need to calculate any additional capital cost. And anything else would be apples to oranges because the cost of Skylon IS total cost.
Both need to add operations which he argues is more expensive for Skylon which is probably correct.

So it all boils down to interest rates and flight rates...

They compute only a one-off count, not a recylce of the acquisition each 10 launches. Basically, it is like buying one skylon and using it 200 times, or buying a falcon 9 and using it 200 times. which is wrong.

Also, keep in mind that a Skylon should have an oeprational life of minimum 30 years. Which means around 6 flights per year, to have the minimu price of  millions. at higher prices you need much less flights.

No, that's not true. They use a different scale for the amortization. It's confusing but correct, they assume to buy 20 Falcons for 200 flights.

do you have a link to the original document? the newspaper article is totally confusing on so many factors that makes little sense to keep commenting on it, but if you have the full document I'd be pleased to read it

Online john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1077 on: 12/16/2015 10:26 PM »
Uh, how far would it hobble Skylon operators to ban traditional toxic hypergols in payloads? Considering all the moves to electric thrusters as it is, what specific scenarios end up essentially needing hypergolic propellants? The missions that come to mind is any kind of short, high thrust scenario where a solid kick stage is undesirable, so some manned systems perhaps?
There's been a lot of talk about electric only propulsion for comm sats but like all parts of the space industry their designers are very conservative and toxic hypergols will not be phased out by anyone over night.

The thing is electric is not a clear win. You (in theory) trade longer station keeping with increased damage from extended passes through the inner Van Allen radiation belt,  unless you fly a Skylon/SUS trajectory to around 5900Km, skipping that part.
"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 #1078 on: 12/16/2015 11:16 PM »
Well, this is where all the nonsense about the supposed advantages of separating operator and manufacturer business cases starts to hit you back...

This is not including development costs but costs of one LV.
That "nonsense" that every transport system mfg and operator follows which does not operate a transport system based around a design for a strategic weapon system uses?

Of course if they did space launch using say, some refurbished artillery pieces they probably would follow the combined mfg/operator model as well.

Funny how that's not taken off as a concept, isn't it
"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 pippin

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The Reaction Engines Skylon Master Thread (5)
« Reply #1079 on: 12/16/2015 11:23 PM »
Well, this is where all the nonsense about the supposed advantages of separating operator and manufacturer business cases starts to hit you back...

This is not including development costs but costs of one LV.
That "nonsense" that every transport system mfg and operator follows which does not operate a transport system based around a design for a strategic weapon system uses?

Of course if they did space launch using say, some refurbished artillery pieces they probably would follow the combined mfg/operator model as well.

Funny how that's not taken off as a concept, isn't it

The nonsense is not to structure the business that way. This can actually make a lot of sense.

But it's nonsense to claim that it would reduce costs. It doesn't. It can help handle risk (not necessarily lower it but make it easier to handle or limit) and it helps to have more appropriate business models for development, manufacturing and operations but it doesn't by itself reduce any costs. That claim was made and it's nonsense.

And now somebody else turns that thing on its head and makes the similarly nonsensical claim that this structure would INCREASE the cost (it doesn't, it may make it more obvious or visible but it doesn't in itself cause fundamental additional costs), that's what I wanted to point out.

It's kind of fair :)
« Last Edit: 12/16/2015 11:23 PM by pippin »

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