Author Topic: The Reaction Engines Skylon Master Thread (1)  (Read 746133 times)

Offline 93143

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Re: The Reaction Engines Skylon Master Thread
« Reply #1120 on: 11/02/2012 07:23 pm »
The User Manual indicates a two-tonne payload to an 800 km SSO.  This doubles to four tonnes for 500 km.

Be aware that these are C2 numbers; D1 is a bit smaller due to technological advances, so it might not lose payload as fast to high altitude and inclination.
« Last Edit: 11/02/2012 07:52 pm by 93143 »

Offline BobCarver

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Re: The Reaction Engines Skylon Master Thread
« Reply #1121 on: 11/02/2012 08:13 pm »
The User Manual indicates a two-tonne payload to an 800 km SSO.  This doubles to four tonnes for 500 km.

Be aware that these are C2 numbers; D1 is a bit smaller due to technological advances, so it might not lose payload as fast to high altitude and inclination.

If you were going to take tourists to a high-altitude station, you would have a chioce of using the present design and transferring the passenger module to an in-space transfer vehicle to transport them to the high-altitude station, or building a bigger version of SKYLON to take them there all the way in a single go. The in-space transfer vehicle would probably be the choice near term, of course. We could speculate about what kind of design would be best for this vehicle, but it might be somewhat off-topic here I suspect, if only because REL have not announced the design of such a vehicle. May be a good subject for a "Reaction Engines Skylon Slave Thread."

Offline 93143

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Re: The Reaction Engines Skylon Master Thread
« Reply #1122 on: 11/03/2012 06:52 am »
Just to be totally clear for all readers, those numbers are for launching from the equator into a 98° sun-synchronous orbit.  Even a low-altitude orbit (~200 km) won't allow much more than 6 tonnes, at least on the C2 (again, D1 might do better).  Launching from a site at 60° latitude adds nearly a tonne to all three numbers.

Launching from the equator into an equatorial orbit, Skylon C2 can haul 11 tonnes to 800 km, or more than 13 tonnes to 500 km.
« Last Edit: 11/03/2012 07:20 am by 93143 »

Offline Turbomotive

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Re: The Reaction Engines Skylon Master Thread
« Reply #1123 on: 11/04/2012 02:54 am »
Regarding bird strike issue, maybe a spaceport could have a fleet of birds of prey to scare them off like they do at Wimbledon. Somewhat retro that your Skylon spaceport would have a role for a Chief Falconer, but anyone have any more effective ideas?
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Offline Warren Platts

Re: The Reaction Engines Skylon Master Thread
« Reply #1124 on: 11/04/2012 03:32 am »
Shotguns?
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Offline john smith 19

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Re: The Reaction Engines Skylon Master Thread
« Reply #1125 on: 11/04/2012 08:04 am »
Regarding bird strike issue, maybe a spaceport could have a fleet of birds of prey to scare them off like they do at Wimbledon. Somewhat retro that your Skylon spaceport would have a role for a Chief Falconer, but anyone have any more effective ideas?
I've asked about this. REL state the design is more resistant for birdstrike. AFAIK Hunting birds are used on some airports but the cries of gulls in distress are also used played through a loud PA system.
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Offline anonymous

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Re: The Reaction Engines Skylon Master Thread
« Reply #1126 on: 11/04/2012 11:08 am »
There's another problem with Quito or most other inland launch sites: sonic boom. Skylon doesn't take off vertically like a rocket, but gradually ascends to 28.5 km over 620 km before switching to rocket mode at Mach 5.5. That's going to create a carpet of sonic boom like Concorde did, except probably worse because Skylon is much bigger and much faster. Concorde was banned from supersonic flight over land. Coastal launch sites may be de rigeur, at least in democratic countries.

Really, there are three different basic conops; single sats to GEO, cargo to a depot, and passengers to a station. Single GEO launches make sense to be equatorial, tourist stations will probably high inclination, and depots probably at 23-28 degrees (ecliptic aligned). The single GEO launches make sense to be equatorial, and so the first real Skylon base will probably be there. But if it works and is economical, I could imagine a proliferation of other launch sites in Europe and North America.

Maybe you would be able to fly over deserts if you stay clear of any towns in them (e.g. from Spaceport USA), but Europe is pretty densely populated, except in the far north, and launches to the east will fly over land before Skylon is above the atmosphere, except from Iceland.

The best sites for freight operations may be islands in the Atlantic, Indian and/or Pacific Oceans, assuming an equatorial orbit destination. But, if you ran cargo or passenger SKYLON flights to a resort hotel in a polar, sun-synchronous orbit (which has advantages from the point of view of visitors always having a view of the Earth lit up in daylight), a launch site nearer the poles wouldn't be unreasonable as there would be no advantage to an equatorial spaceport for such a mission. Your passenger traffic is likely to be European, American, Chinese, Korean, Arabian and Indian. Europeans and Americans might find a spaceport on an island in the Atlantic more convenient, while the Asian nations would probably like to use an island in the Pacific. Indians and Arabs would prefer a site either in some remote location within their countries or an island in the Indian Ocean.

Probably the bigger consideration is noise from the takeoff, as Hempsell has pointed out numerous times, which argues for sparsely-populated island locations for siting launch facilities.

Sparsely-populated islands near the equator sound like the best place for launch sites, but islands that are big enough for a 5.5 km runway tend to have quite substantial populations, while ones that have few inhabitants tend to be too small.

Ascension Island is a possibility in the Atlantic, but although it already has a 3 km runway, it might be tricky to fit a 5.5 km one because the island is rather mountainous. I don't see why it would be preferable to Kourou.

Diego Garcia would be the obvious location in the Indian Ocean, but political considerations would probably rule it out. Gan in the Maldives could be good if the runway could be extended far enough. Both these locations suffer from the disadvantage they're scarcely above sea level and will probably disappear beneath the waves within a few decades.

There is plenty of space on Kiritimati in the Pacific, but it is also a coral atoll that will disappear, although as the largest coral island in the world it's higher (as much as 2 metres above sea level!) and will last quite a bit longer. It's already the location Sea Launch operates from.

Volcanic oceanic  islands with tropical or temperate climates that are big enough tend to have substantial populations, either because they're so fertile or because they're so attractive to tourists. The Falkland Islands and Kerguelen have few inhabitants and could easily fit spaceports, but they're extremely windy and blustery, so not ideal for Skylon.

I don't see what's wrong with coastal sites like Kourou, Alcantara and Cape Canaveral.

Edit: Kiritimati is no good for Skylon - there are millions of birds.
« Last Edit: 11/04/2012 11:53 am by anonymous »

Offline Kharkov

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Re: The Reaction Engines Skylon Master Thread
« Reply #1127 on: 11/04/2012 12:05 pm »
There's another problem with Quito or most other inland launch sites: sonic boom. Skylon doesn't take off vertically like a rocket, but gradually ascends to 28.5 km over 620 km before switching to rocket mode at Mach 5.5. That's going to create a carpet of sonic boom like Concorde did, except probably worse because Skylon is much bigger and much faster. Concorde was banned from supersonic flight over land. Coastal launch sites may be de rigeur, at least in democratic countries.

-Snip-

Sparsely-populated islands near the equator sound like the best place for launch sites, but islands that are big enough for a 5.5 km runway tend to have quite substantial populations, while ones that have few inhabitants tend to be too small.

Ascension Island is a possibility in the Atlantic, but although it already has a 3 km runway, it might be tricky to fit a 5.5 km one because the island is rather mountainous. I don't see why it would be preferable to Kourou.

I don't see what's wrong with coastal sites like Kourou, Alcantara and Cape Canaveral.
Kourou, French Guiana is a good spot for a launch and, assming Skylon gets sigificant financial support from ESA, will probably be the site for Skylon launches.

Alcantara, Brazil is closer to the equator and, if Skylon gets significant private (non-ESA) funding, will probably be the preferred site for Skylon launches.

Cape Canaveral (28 degrees north, wouldn't Hawaii (21 degrees north) be better?), USA, raises an important question. Come 2022, could an American citizen/corporation actually buy a Skylon launch vehicle with SABRE engines (with REL's pre-cooler) for operation within the US?

Would they be breaking the law due to ITARS? The question of purchasing a Skylon AFTER it's been developed doesn't seem to have been clearly answered by anyone involved.

Aside from my earlier post recommending the coastal town of Lamu, Kenya, I'd also like to note that Ascension Island does have room for a 5.5Km runway on it's southern side, some distance from where the inhabitants seem to live on the northern side. The downside is that the east-west-facing runway would need to span three rivers/large streams. That said, it would keep a UK spaceplane operating from UK soil.

That said, Alan Bond (I'm sure of this but I still can't find the video that had him saying so) said that if the STRICT/STERN Expansion/Deflection nozzles work then they'd shave 1Km to 1.5Km off that takeoff run so the 4Km start-to-rotation distance reduces to 2.5Km to 3Km reducing the whole thing to 4Km to 4.5Km. That should simplify things at Ascension as they do seem to have some space at the southern end of the existing runway.

And yes, Skylon does seem destined to be a 'noisy beast' as Mark Hempsell puts it so overland flying would be right out.
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Offline anonymous

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Re: The Reaction Engines Skylon Master Thread
« Reply #1128 on: 11/04/2012 01:58 pm »
Cape Canaveral (28 degrees north, wouldn't Hawaii (21 degrees north) be better?), USA, raises an important question.

You're right, Cape Canaveral isn't ideal for equatorial orbits, but where would you find space for something as noisy as the Space Shuttle in Hawaii?

Quote
Aside from my earlier post recommending the coastal town of Lamu, Kenya

The coast of Kenya looks like it might be a good place for an Indian Ocean launch site, but Lamu is a World Heritage Site and Lonely Planet says: "The undisputed gem of the Kenyan coast is Lamu and her sister islands in the Lamu archipelago."

Quote
I'd also like to note that Ascension Island does have room for a 5.5Km runway on it's southern side, some distance from where the inhabitants seem to live on the northern side. The downside is that the east-west-facing runway would need to span three rivers/large streams.

It may be possible to squeeze a 5.5 km runway in, but I wasn't sure. The south of the island is much steeper than the south-west.

Quote
That said, it would keep a UK spaceplane operating from UK soil.

I don't think we (British) would really care much about that.

Quote
That said, Alan Bond (I'm sure of this but I still can't find the video that had him saying so) said that if the STRICT/STERN Expansion/Deflection nozzles work then they'd shave 1Km to 1.5Km off that takeoff run so the 4Km start-to-rotation distance reduces to 2.5Km to 3Km reducing the whole thing to 4Km to 4.5Km. That should simplify things at Ascension as they do seem to have some space at the southern end of the existing runway.

Yes, 4 km to 4.5 km looks quite manageable for Ascension Island.
« Last Edit: 11/04/2012 02:12 pm by anonymous »

Offline Carreidas 160

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Re: The Reaction Engines Skylon Master Thread
« Reply #1129 on: 11/04/2012 02:11 pm »
Cape Canaveral (28 degrees north, wouldn't Hawaii (21 degrees north) be better?), USA, raises an important question.

Okay, Cape Canaveral isn't ideal for equatorial orbits, but where would you find space for something as noisy as the Space Shuttle in Hawaii?

Launching from the equator is only a factor when you want to get to GSO.  Cape Canaveral only shaves off ±50m/s delta-V compared to equator, but it benefits from having most infrastructure in place + short supply lines.

You don't want to launch Skylon from Quito, Alcantara, Honolulu, Easter Island, or whatever remote atoll (and DEFINITELY NOT Kenya, PLEASE) just for the sake of a few m/s of delta-V. Long supply lines and lack of infrastructure make those options a no-go.

Offline anonymous

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Re: The Reaction Engines Skylon Master Thread
« Reply #1130 on: 11/04/2012 08:06 pm »
Launching from the equator is only a factor when you want to get to GSO.  Cape Canaveral only shaves off ±50m/s delta-V compared to equator, but it benefits from having most infrastructure in place + short supply lines.

You don't want to launch Skylon from Quito, Alcantara, Honolulu, Easter Island, or whatever remote atoll (and DEFINITELY NOT Kenya, PLEASE) just for the sake of a few m/s of delta-V. Long supply lines and lack of infrastructure make those options a no-go.

Yet Europe launches from Kourou, Brazil has Alcantara, rather than a launch site near Rio de Janiero/Sao Paulo, and Sea Launch does it off Kiritimati, rather than Russia or Ukraine, where its rockets are made.

Offline simonbp

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Re: The Reaction Engines Skylon Master Thread
« Reply #1131 on: 11/04/2012 09:29 pm »
Most of the money-making flights from Korou are to GEO, where latitude makes the most difference. And, Europe is not exactly the best place for launching expendable rockets eastwards, especially during the Cold War, when the site was built...

Also, has anything actually launched from Alcantara yet? Customers are not exacting banging down the doors to launch from there.
« Last Edit: 11/04/2012 09:31 pm by simonbp »

Offline Jim

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Re: The Reaction Engines Skylon Master Thread
« Reply #1132 on: 11/04/2012 09:52 pm »
[quote author=anonymous link=topic=24621.msg976099#msg976099
Yet Europe launches from Kourou, Brazil has Alcantara, rather than a launch site near Rio de Janiero/Sao Paulo, and Sea Launch does it off Kiritimati, rather than Russia or Ukraine, where its rockets are made.
[/quote]

Sealaunch is almost dead.  Alcantara has no real business and is a national base.

Cape Canaveral and Baikonur negate your argument.

Offline Jim

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Re: The Reaction Engines Skylon Master Thread
« Reply #1133 on: 11/04/2012 09:56 pm »
Repeating what I said earlier

If you buy into the highly unlikely scenario that Skylon will actually work, then the loss of payload capacity due to launch latitude really doesn't  matter. Because concept is supposedly going to drastically reduce the cost of launches; multiple launches can be used to achieve a given mass to orbit vs optimizing the capacity on a given launch or launch site.

French Guiana was chosen for ELV's and not an RLV that supposedly going to change space launch. Other costs will dictate launch location rather than performance considerations (i.e it might be more economical to launch from Europe vs French Guiana, due to additional  logistical costs)

Offline anonymous

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Re: The Reaction Engines Skylon Master Thread
« Reply #1134 on: 11/05/2012 07:45 am »
Asked about the location of Skylon spaceports, REL's Roger Longstaff responded:

For the operator of a Skylon vehicle the latitude of the spaceport will impact the mass that can be lifted to a given orbit. For high volume cargo flights e.g. for operators wishing to use their vehicles for large projects such as construction of space stations, large satellite constellations and interplanetary missions it would be most cost effective to use an equatorial spaceport in a remote location. We imagine that several sites would emerge around the Earth’s equator. Where the cost per mass to orbit is less critical or where polar orbits are a priority the Skylon spaceport could be located away from the equator, including in the UK.

Skylon operations will also need to comply with a variety of regulations and this will impact on the exact location. An obvious example is that the spaceports are likely to be located away from densely populated areas to avoid the impact of noise and to reduce insurance costs. The regulatory environment for Skylon is currently being explored by the UK government.


Read more: http://www.theengineer.co.uk/sectors/aerospace/in-depth/skylon-and-sabre-your-questions-answered/1014164.article#ixzz2BKtL2DbR

Offline anonymous

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Re: Skylon
« Reply #1135 on: 11/05/2012 08:02 am »
This is what Mark Hempsell told us:

With regards to runways, the spaceport location is up to the operator, if they want to offer the most flexible service they should set up at the equator with eastern ocean views (like existing launch vehicles), but specialists services could be located elsewhere – the performance to high inclinations like Sun synchronous is slightly improved by high inclination launch sites.  The User Manual shows the performance for launch sites up to 60 degrees latitude.

We assumed sea level sites, since we pictured the takeoff being close to an ocean. Altitude should provide a slight improvement in performance but may also impact the take off speed – so an even longer runway please.  We have not evaluated the impact of high altitude launches.

Offline Warren Platts

Re: The Reaction Engines Skylon Master Thread
« Reply #1136 on: 11/05/2012 02:14 pm »
Thanks for tracking down Mr. Hempsell's comments.

Speaking of high altitude launches, I wonder if it would be possible to do an airplane launch from 50,000 feet or something... ;)
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Offline truth is life

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Re: The Reaction Engines Skylon Master Thread
« Reply #1137 on: 11/05/2012 02:27 pm »
Launching from the equator is only a factor when you want to get to GSO.  Cape Canaveral only shaves off ±50m/s delta-V compared to equator, but it benefits from having most infrastructure in place + short supply lines.

You don't want to launch Skylon from Quito, Alcantara, Honolulu, Easter Island, or whatever remote atoll (and DEFINITELY NOT Kenya, PLEASE) just for the sake of a few m/s of delta-V. Long supply lines and lack of infrastructure make those options a no-go.

Might make sense if you were doing some kind of touristy thing, though--come out to beautiful Hawai'i (historical Easter Island, etc.) for a few days, then catch your flight up to the tourist station! Then spend a few days in beautiful Hawai'i, etc. before heading back to "real life". A two-in-one package. Seems marginal at best, though.

On Alcantra, I don't see how its supply lines vis-a-vis Skylon are any longer than Kourou's...

Offline BobCarver

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Re: The Reaction Engines Skylon Master Thread
« Reply #1138 on: 11/05/2012 02:30 pm »
Repeating what I said earlier

If you buy into the highly unlikely scenario that Skylon will actually work, then the loss of payload capacity due to launch latitude really doesn't  matter. Because concept is supposedly going to drastically reduce the cost of launches; multiple launches can be used to achieve a given mass to orbit vs optimizing the capacity on a given launch or launch site.

French Guiana was chosen for ELV's and not an RLV that supposedly going to change space launch. Other costs will dictate launch location rather than performance considerations (i.e it might be more economical to launch from Europe vs French Guiana, due to additional  logistical costs)


Jim, you have a reputation as a smart guy and it's probably well deserved. But, there are a lot of smart guys who have looked at the SKYLON design and said it will work. Yet, you insist on vague opinions with no solid argument that SKYLON won't work. It's fine to offer an opinion, but without any scientific or engineering rationale to justify your opinion, it's not worth the e-paper it's written on.

Otherwise, I agree with you about logistics being a primary factor.

Offline Jim

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Re: The Reaction Engines Skylon Master Thread
« Reply #1139 on: 11/05/2012 02:53 pm »

Jim, you have a reputation as a smart guy and it's probably well deserved. But, there are a lot of smart guys who have looked at the SKYLON design and said it will work.

Actually, not true, not enough of the right smart people have looked at it.  The fact that there is no other similar system in development or that there is not a bunch of money being thrown at it is telling.   Also, I define "working" as being cheaper that existing systems.   I don't mean like the shuttle which flew but did nothing to reduce the cost of spacelaunch.
« Last Edit: 11/05/2012 02:55 pm by Jim »

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