Author Topic: The Reaction Engines Skylon Master Thread (5)  (Read 419897 times)

Offline lkm

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1560 on: 06/02/2016 11:02 PM »
BTW, the Skylon are expected to fly every other day.  140/month was the production rate of Skylons to keep up a million flights per year.  If you rebuild them at 500 flights, it would reduce the projection rate to 70/month.  The cost estimate graph mentioned in this thread gets down to $120/kg at around 100,000 flights per year.  The electric propulsion (at 30,000 tons per month) add about $55/kg to the cost.
These are quite an absurd numbers, really. You'd need to have a multi-planetary species to support anything remotely near that number, it's such a high number for one launch vehicle to go that we are stepping into the realm of sci-fi. It's not feasible within a lifetime of any of us.
For context both Airbus and Boeing routinely build more than 125 jet airliners per month  and there are easily more than 30 million airliner flights per year yet there are many people alive today for whom those numbers have come from nothing within their lifetimes.

Also I don't see how if a million flights a year are needed to build and support a global space solar power infrastructure off world colonies are needed to supply demand for that flight rate, the demand is the space solar power infrastructure which is what dictated the flight rate in the first place.

Offline flymetothemoon

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1561 on: 06/03/2016 01:52 PM »
Those of you who know my ID, know I am a huge fan of the Reaction Engine chaps. Thing is I am also a huge Elon Musk fan - and he says solar powered satellites are unnecessary. Being a huge REL fan for years I picked up on that comment straight away since I know of the old REL SPS study. In this video (at 3 minutes) he says, "If anyone should be in favour of solar power satellites it should be me ... but this is completely unnecessary"


« Last Edit: 06/03/2016 01:58 PM by flymetothemoon »

Offline t43562

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1562 on: 06/03/2016 04:03 PM »
Those of you who know my ID, know I am a huge fan of the Reaction Engine chaps. Thing is I am also a huge Elon Musk fan - and he says solar powered satellites are unnecessary.

It's not as if his proposal is practical either at the moment  - I'm not buying solar panels for example because of the cost (installation, inverter etc).  It's actually a rip-off for those of us with small roofs where I live and I can save the planet more by buying a modern boiler.

One might as well work through these ideas for the sake of understanding them though and it can lead to other ideas.  e.g. a solar powered tug might be quite useful.

You might have a solar power station in orbit to power those micro-chip interstellar ships that Stephen Hawking etc have been talking about.  It could boost them up to near light speed.

Perhaps one day we will try to put up a sun shade to cool the earth down! :-)

Skylon will be at the ready to help make nutty ideas possible, crazy ideas imaginable.

Offline SICA Design

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1563 on: 06/03/2016 04:09 PM »
Those of you who know my ID, know I am a huge fan of the Reaction Engine chaps. Thing is I am also a huge Elon Musk fan - and he says solar powered satellites are unnecessary. Being a huge REL fan for years I picked up on that comment straight away since I know of the old REL SPS study. In this video (at 3 minutes) he says, "If anyone should be in favour of solar power satellites it should be me ... but this is completely unnecessary"

This is fairly old now, discussed here http://forum.nasaspaceflight.com/index.php?topic=30107.msg969044#msg969044 (Oct 2012) and more recently here http://forum.nasaspaceflight.com/index.php?topic=17902.msg1511703#msg1511703 (May 2016)

If you want to compare SPS with a relatively small scale terrestrial system located in the desert of your choice then I'd agree with Musk, with the caveat that his fabled photon-to-electron-to-photon-to-electron dismissal is actually not that bad at all: space solar beats equatorial noon sun by 37%, the dc-(space)-to-microwave-to-dc-(grid) can be achieved with an efficiency of around 50%. Add in the fact that power is constant except for a few hours each equinox (compared with terrestrial day/night cycles and weather) then, on average, space solar produces about 11 times more energy than the equivalent terrestrial system.

If your goal is to wean humanity off fossil fuels, then your options are limited. Take the (not-so-sunny) UK for example. Terrestrial solar farms average approximately 10W/m^2. An equivalent grid-scale rectenna would be limited only by the safe-level central peak beam intensity of 250-350W/m^2 (one-quarter to one-third noon sunlight intensity), giving an average power density of 60W/m^2 - i.e. requiring only one-sixth the land area, which could remain dual use for growing crops.

Of-course if you are contemplating fully renewable energy (as opposed to sustainable energy including fission/fusion power), then almost everything other than SPS requires truly massive grid-scale storage to meet baseload requirements.

Once as a civilisation we decide we can no-longer live with fossil fuels, and probably before fusion can be scaled globally, we will need Skylon, or something very much like it, to achieve the high flight rates - costs be damned!
« Last Edit: 06/03/2016 04:11 PM by SICA Design »

Offline lkm

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1564 on: 06/03/2016 06:23 PM »
Those of you who know my ID, know I am a huge fan of the Reaction Engine chaps. Thing is I am also a huge Elon Musk fan - and he says solar powered satellites are unnecessary. Being a huge REL fan for years I picked up on that comment straight away since I know of the old REL SPS study. In this video (at 3 minutes) he says, "If anyone should be in favour of solar power satellites it should be me ... but this is completely unnecessary"

This is fairly old now, discussed here http://forum.nasaspaceflight.com/index.php?topic=30107.msg969044#msg969044 (Oct 2012) and more recently here http://forum.nasaspaceflight.com/index.php?topic=17902.msg1511703#msg1511703 (May 2016)

If you want to compare SPS with a relatively small scale terrestrial system located in the desert of your choice then I'd agree with Musk, with the caveat that his fabled photon-to-electron-to-photon-to-electron dismissal is actually not that bad at all: space solar beats equatorial noon sun by 37%, the dc-(space)-to-microwave-to-dc-(grid) can be achieved with an efficiency of around 50%. Add in the fact that power is constant except for a few hours each equinox (compared with terrestrial day/night cycles and weather) then, on average, space solar produces about 11 times more energy than the equivalent terrestrial system.

If your goal is to wean humanity off fossil fuels, then your options are limited. Take the (not-so-sunny) UK for example. Terrestrial solar farms average approximately 10W/m^2. An equivalent grid-scale rectenna would be limited only by the safe-level central peak beam intensity of 250-350W/m^2 (one-quarter to one-third noon sunlight intensity), giving an average power density of 60W/m^2 - i.e. requiring only one-sixth the land area, which could remain dual use for growing crops.

Of-course if you are contemplating fully renewable energy (as opposed to sustainable energy including fission/fusion power), then almost everything other than SPS requires truly massive grid-scale storage to meet baseload requirements.

Once as a civilisation we decide we can no-longer live with fossil fuels, and probably before fusion can be scaled globally, we will need Skylon, or something very much like it, to achieve the high flight rates - costs be damned!

What SPS is uniquely good at is providing power to a place without having to physically and permanently install a billion dollars of capital investment in that place. So for things like forward operating bases, refugee camps or unstable nations power can be supplied on a temporary basis or without risking your capital investment on the ground. For these uses the actual cost of power production is very much less important as SPS is competing with non consumption not other forms of production.

 SPS could also spread the power market from a regional one to a continental one as a Satellite could chose where to beam its power on a moment to moment basis across a much larger area than conventional power production can shift power to meet demand.

Online Chris Bergin

Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1565 on: 06/03/2016 06:34 PM »
This thread is to do with Reaction Engines/Skylon. If you want to discuss satellites, start a new thread.

(Reacting to report to mod alerts......lots of them today)

Offline francesco nicoli

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1566 on: 06/05/2016 03:22 PM »
Guys, I am sorry to have brought the issue up. But to me it sounds really at odds with reality to make hypotheses on the opportunities given by building 140 Skylons per month when we are very far away from securing even only the first 10% of the development programme.

Offline t43562

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1567 on: 06/06/2016 07:38 AM »
If there was a very great project, could Skylon be scaled up?  We know that scaling down is problematic.  Could you double the volume, add 2 more engines and then carry twice the payload?

Offline 93143

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1568 on: 06/06/2016 10:16 AM »
http://forum.nasaspaceflight.com/index.php?topic=24621.msg735577#msg735577

Quote from: Hempsell
We have not seriously explored taking the SKYLON type vehicle up to the heavy lift class but the few “fun exercises” we have done have not shown any fundamental upper limit technically but the economics go to pot. Basically making the systems as small as possible while still capturing the main market (i.e. not small sats) throws the economic burden on to more launches (where reusables score) and off development cost and acquisition cost (where reusable suffer).

Sounds like a yes.
« Last Edit: 06/06/2016 10:16 AM by 93143 »

Offline Turbinia

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1569 on: 06/07/2016 08:09 PM »
I have just listened to the the latest Planetary Radio podcast which had a very interesting interview with Andy Weir who presented his vision for low cost access to space for people and freight and leading to an LEO space tourism industry. The kind of assumptions which Andy outlines in the interview seems to me to point directly at a Skylon type solution (No he didn't mention Skylon).

Anyway the podcast can be found here http://www.planetary.org/multimedia/planetary-radio/show/2016/0606-2016-contact-conference [

Offline Turbinia

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1570 on: 06/07/2016 08:14 PM »
RE my post above this is the correct link. Sorry it was my first post.

http://www.planetary.org/multimedia/planetary-radio/show/2016/0606-2016-contact-conference.html

Offline Robotbeat

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1571 on: 06/07/2016 08:17 PM »
http://forum.nasaspaceflight.com/index.php?topic=24621.msg735577#msg735577

Quote from: Hempsell
We have not seriously explored taking the SKYLON type vehicle up to the heavy lift class but the few “fun exercises” we have done have not shown any fundamental upper limit technically but the economics go to pot. Basically making the systems as small as possible while still capturing the main market (i.e. not small sats) throws the economic burden on to more launches (where reusables score) and off development cost and acquisition cost (where reusable suffer).

Sounds like a yes.
jongoff makes a good argument for scaling down to like ~3 tons LEO, then using refueling and a transfer stage to put those 3 ton payloads directly to GSO. That would be about equivalent to 5 tons GTO.

So I wonder if Skylon could halve the cost (and development time) if they went for a ~3 ton payload instead of 10-15.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1572 on: 06/08/2016 12:55 AM »
http://forum.nasaspaceflight.com/index.php?topic=24621.msg735577#msg735577

Quote from: Hempsell
We have not seriously explored taking the SKYLON type vehicle up to the heavy lift class but the few “fun exercises” we have done have not shown any fundamental upper limit technically but the economics go to pot. Basically making the systems as small as possible while still capturing the main market (i.e. not small sats) throws the economic burden on to more launches (where reusables score) and off development cost and acquisition cost (where reusable suffer).

Sounds like a yes.
jongoff makes a good argument for scaling down to like ~3 tons LEO, then using refueling and a transfer stage to put those 3 ton payloads directly to GSO. That would be about equivalent to 5 tons GTO.

So I wonder if Skylon could halve the cost (and development time) if they went for a ~3 ton payload instead of 10-15.
Where does this refuelling come from? Skylon already has a Skylon Upper Stage to handle the GTO, which like Skylon is designed to be reusable.

Provided you don't hit the machinery or building limits (which impose step change costs) bigger is not that much more expensive, and hence smaller is not that much more cheaper.
"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 Avron

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1573 on: 06/08/2016 01:03 AM »
Skylon already has a Skylon Upper Stage

six year later ...

... can you post a picture of this Skylon.. or at least a working air breathing rocket engine ?

Offline Robotbeat

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1574 on: 06/08/2016 01:12 AM »
http://forum.nasaspaceflight.com/index.php?topic=24621.msg735577#msg735577

Quote from: Hempsell
We have not seriously explored taking the SKYLON type vehicle up to the heavy lift class but the few “fun exercises” we have done have not shown any fundamental upper limit technically but the economics go to pot. Basically making the systems as small as possible while still capturing the main market (i.e. not small sats) throws the economic burden on to more launches (where reusables score) and off development cost and acquisition cost (where reusable suffer).

Sounds like a yes.
jongoff makes a good argument for scaling down to like ~3 tons LEO, then using refueling and a transfer stage to put those 3 ton payloads directly to GSO. That would be about equivalent to 5 tons GTO.

So I wonder if Skylon could halve the cost (and development time) if they went for a ~3 ton payload instead of 10-15.
Where does this refuelling come from? Skylon already has a Skylon Upper Stage to handle the GTO, which like Skylon is designed to be reusable.

Provided you don't hit the machinery or building limits (which impose step change costs) bigger is not that much more expensive, and hence smaller is not that much more cheaper.
Reduce the cost enough, and it looks attractive versus developing Ariane 6. Or, you know, let perfect be the enemy of the good and be content with nothing. If a reduction in payload from 15 tons to 3 tons means a reduction in cost to near Ariane 6 costs, then all of a sudden, Skylon looks very attractive.

And being much, much smaller would make operating out of more airports a LOT easier by reducing the infrastructure costs (hydrogen, etc) and reducing the required runway length. That'd dramatically expand the client base. That is Reaction Engines' business plan, right?


...a reduction of payload from 15 tons to 3 tons could result in a reduction in development costs from $12 billion to $4.5 billion. That is the same as Ariane 6.
« Last Edit: 06/08/2016 01:15 AM by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Online Chris Bergin

Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1575 on: 06/08/2016 11:58 AM »
Skylon already has a Skylon Upper Stage

six year later ...

... can you post a picture of this Skylon.. or at least a working air breathing rocket engine ?

Probably could have said it less sarcastically ;) But this really needs some progress now. If other vehicles are subject to questions, this one should be too. To me it feels like it's stuck in the mud somewhat. I'd "love it" if I could be proven wrong. Keegan-style (UK folk will get that reference).

Offline Star One

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1576 on: 06/08/2016 12:32 PM »
Skylon already has a Skylon Upper Stage

six year later ...

... can you post a picture of this Skylon.. or at least a working air breathing rocket engine ?

Probably could have said it less sarcastically ;) But this really needs some progress now. If other vehicles are subject to questions, this one should be too. To me it feels like it's stuck in the mud somewhat. I'd "love it" if I could be proven wrong. Keegan-style (UK folk will get that reference).

Of late I'd say it maybe that BAE who are steering the ship and they have other things in mind for technology than Skylon.

Offline supersubie

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1577 on: 06/08/2016 07:15 PM »
Just saw that the USAF are expected to announce a development programmer based around the SABRE pre cooling technology later this year. Is this new information or just a continuation of the studies they have been working on together in the past?

http://nextbigfuture.com/2016/06/us-air-force-research-will-develop.html

Offline Star One

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The Reaction Engines Skylon Master Thread (5)
« Reply #1578 on: 06/08/2016 07:18 PM »
Just saw that the USAF are expected to announce a development programmer based around the SABRE pre cooling technology later this year. Is this new information or just a continuation of the studies they have been working on together in the past?

http://nextbigfuture.com/2016/06/us-air-force-research-will-develop.html

I am sure this was initially reported a little while back. This is pretty intriguing & probably will finally represented some  full scale forward momentum for REL.
« Last Edit: 06/08/2016 07:23 PM by Star One »

Offline john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1579 on: 06/08/2016 07:47 PM »
Just saw that the USAF are expected to announce a development programmer based around the SABRE pre cooling technology later this year. Is this new information or just a continuation of the studies they have been working on together in the past?

http://nextbigfuture.com/2016/06/us-air-force-research-will-develop.html
The article still thinks this is for a LACE cycle.

That puts doubt on the rest of the article.  :(

Likewise if the USAFRL want a M5 engine, not a ground-to-space engine SABRE is a very odd choice to start from, as REL could have told them.

The whole "two-stage-is-easier-than-one" mantra is simple wrong if SABRE can demonstrate it's full capabilities.

It's like turning an E-type jaguar into a hearse.  :)

Possible, but why do so?
« Last Edit: 06/08/2016 07:48 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.

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