british rocketplane by 2020?

[Antice]

this thread has been asleep for a long time. Now I'ma brush it off again since it seems like skylon is about to get a jump up in it's technology readiness level.
Linky to Ractionengines ltd,s news page.

And also. a direct link to a news article where Alan bond is making a statement about the readiness level of skylon. (oopsie. 3,5Mb PDF behind that link)

Here is the relevant statement for the connectively impaired.

The technology Demonstration Programme will last around 2.5 years and will benefit from another €1 million from ESA at the halfway point of the programme. It will take Reaction Engines from a Technology readiness Level (TRL) of 2/3 up to 4/5.
Managing director Alan Bond said: "It is a very exciting time for the company and our innovative spaceplane. We are relishing the opportunity to demonstrate its concepts and findings. Skylon's first flight is planned for 2018 with its entry into service expected to take place in 2020."

credit: Spaceflight

[Garrison]

this thread has been asleep for a long time. Now I'ma brush it off again since it seems like skylon is about to get a jump up in it's technology readiness level.
Linky to Ractionengines ltd,s news page.

And also. a direct link to a news article where Alan bond is making a statement about the readiness level of skylon. (oopsie. 3,5Mb PDF behind that link)

Here is the relevant statement for the connectively impaired.


credit: Spaceflight

I really hope this is going to work, they could make back the costs just charging people to watch it take off.

[Antice]

I really hope this is going to work, they could make back the costs just charging people to watch it take off.

Yeah. they could set up a stand along the runway at a safeish distance. not too safe. we wanna feel the ground rumble as it accelerates down the runway right?
The income on the beer sales alone would finance a launch or 2

[Antice]

Another month and some news from the makers of the skylon.

Looks like they are working hard on refining the design and finalizing the D1 revision. no timeframe for when we can look at it tho. so for now we have to live with the C1 specs from the first revision of the users manual.
all docks can be found at their website.

Have to admit i am eagerly waiting for the specs on the D1 configuration. skylon is slowly crawling towards becoming reality.

[Antice]

June update is finally here. I skipped the last two months since so many where discussing it on other threads. besides there weren't all that many interesting details to report.

a) a larger wing as D1 is heavier, and
b) the rear fuselage is not a circular cross section but is flattened, a little like the Space Shuttle, to give more rearward lift at high speeds.

These are the major changes so far.
Apparently they are awaiting the SABRE 4 engine model before refining the design further.
In other areas: The reports from DLR are in, They are currently working on recommendations for improving the D1 configuration in light of these results.

All in all i think they are making fine progress towards realizing the skylon concept into a working space plane. I'm really looking forward towards seeing the D1 design unveiled.
Watching a project grow like this is very fascinating indeed.

[Garrison]

June update is finally here. I skipped the last two months since so many where discussing it on other threads. besides there weren't all that many interesting details to report.


These are the major changes so far.
Apparently they are awaiting the SABRE 4 engine model before refining the design further.
In other areas: The reports from DLR are in, They are currently working on recommendations for improving the D1 configuration in light of these results.

All in all i think they are making fine progress towards realizing the skylon concept into a working space plane. I'm really looking forward towards seeing the D1 design unveiled.
Watching a project grow like this is very fascinating indeed.

It is, and they are just quietly working their way through the practicalities, now if they could just quietly acquire £10 billion they would be all set.

[KB73RR]

The whole thing sounds like the areocar concept.

There is an areocar available in the US beginning in 2011.

http://www.flightglobal.com/blogs/fl...a-reality.html

However, I agree with the spirit of your comment. In my opinion, SSTO might be technically possible at some point in the distant future. At best it will always be a compromise just like the aerocar, which is really neither a very good car nor a very good aircraft.

Thus far even partially re-usable launchers have failed to live up to cost expectations. STS is a prime example. The Orbital Sciences Pegasus XL system is better, but that's only because of the L-1011 part of the system. The Pegasus itself is more or less a conventional rocket - three stages at that. SpaceShipOne and SpaceShipTwo are not capable of orbit so in my opinion they don't really qualify as launchers. The fastest airbreather so far is the X-51A Waverider and it has only managed about Mach 6 for 200 seconds. That demonstrates the extreme difficulty of achieving sustained hypersonic velocities.

The Wiki article (http://en.wikipedia.org/wiki/Reaction_Engines_SABRE) about the SABRE engine makes some amazing claims. To quote, "The engine gives good fuel efficiency peaking at about 2800 seconds within the atmosphere. Typical all-rocket systems are around 450 at best, and even "typical" nuclear thermal rockets only about 900 seconds." Are they talking about specific impulse or specific thrust or what? Are they claiming efficiencies in the range of ion engines? Then there is the matter of the helium powered turbopumps re-cycling waste heat. Why not do the same using the hydrogen fuel? The helium system just seems like extra mass.

My gut feeling is that this whole concept is fundamentally flawed. I find it hard to believe that they can achieve the engine performance claimed. I don't believe it is possible to design an airframe that can be sufficiently aerodynamically efficient across such a wide range of airspeeds. I don't believe they can build it light enough to carry sufficient fuel for SSTO and still handle the dynamic stresses and thermal issues of SSTO. And even IF they could do all that, I seriously doubt that the life cycle cost could be competitive with more conventional commercial launchers such as those being demostrated already by SpaceX.

whoops - I forgot the X-43A 2nd and 3rd flights. The 2nd flight reached Mach 7 and the 3rd almost Mach 10. Both included very brief periods of scramjet (airbreathing) operation and there was I believe some acceleration during the 2nd flight.

[Garrison]

There is an areocar available in the US beginning in 2011.

http://www.flightglobal.com/blogs/fl...a-reality.html

However, I agree with the spirit of your comment. In my opinion, SSTO might be technically possible at some point in the distant future. At best it will always be a compromise just like the aerocar, which is really neither a very good car nor a very good aircraft.

Thus far even partially re-usable launchers have failed to live up to cost expectations. STS is a prime example. The Orbital Sciences Pegasus XL system is better, but that's only because of the L-1011 part of the system. The Pegasus itself is more or less a conventional rocket - three stages at that. SpaceShipOne and SpaceShipTwo are not capable of orbit so in my opinion they don't really qualify as launchers. The fastest airbreather so far is the X-51A Waverider and it has only managed about Mach 6 for 200 seconds. That demonstrates the extreme difficulty of achieving sustained hypersonic velocities.

The Wiki article (http://en.wikipedia.org/wiki/Reaction_Engines_SABRE) about the SABRE engine makes some amazing claims. To quote, "The engine gives good fuel efficiency peaking at about 2800 seconds within the atmosphere. Typical all-rocket systems are around 450 at best, and even "typical" nuclear thermal rockets only about 900 seconds." Are they talking about specific impulse or specific thrust or what? Are they claiming efficiencies in the range of ion engines? Then there is the matter of the helium powered turbopumps re-cycling waste heat. Why not do the same using the hydrogen fuel? The helium system just seems like extra mass.

My gut feeling is that this whole concept is fundamentally flawed. I find it hard to believe that they can achieve the engine performance claimed. I don't believe it is possible to design an airframe that can be sufficiently aerodynamically efficient across such a wide range of airspeeds. I don't believe they can build it light enough to carry sufficient fuel for SSTO and still handle the dynamic stresses and thermal issues of SSTO. And even IF they could do all that, I seriously doubt that the life cycle cost could be competitive with more conventional commercial launchers such as those being demostrated already by SpaceX.

Well luckily your 'belief' isn't relevant. Try expanding your research beyond Wiki, perhaps even to, for example the company actually building the SABRE and Skylon:

Reaction Engines

Seriously if you think this bears any relation to the aerocar you really have no clue about the Skylon project.

[KB73RR]

Well luckily your 'belief' isn't relevant. Try expanding your research beyond Wiki, perhaps even to, for example the company actually building the SABRE and Skylon:

Reaction Engines

Seriously if you think this bears any relation to the aerocar you really have no clue about the Skylon project.

Thanks for the suggestion. I was intrigued by the OP and progress reports in the previous posts so I actually did look at their site, the previously cited wiki article, all readily available info about the principals, and I ran a D&B on the company too. The bottom line is they are just a handful of smart guys with a grand vision, an apparently politically-related ESA contract, and a slick web site. I wish they would succeed with their grand vision, but it's just a CGI spaceplane - and that's probably all it will ever be. "No Clue"? Perhaps, but for now my venture capital is going elsewhere.

[Garrison]

Thanks for the suggestion. I was intrigued by the OP and progress reports in the previous posts so I actually did look at their site, the previously cited wiki article, all readily available info about the principals, and I ran a D&B on the company too. The bottom line is they are just a handful of smart guys with a grand vision, an apparently politically-related ESA contract, and a slick web site. I wish they would succeed with their grand vision, but it's just a CGI spaceplane - and that's probably all it will ever be. "No Clue"? Perhaps, but for now my venture capital is going elsewhere.

Errant nonsense, and no doubt your money will going on a bridge to lurk under...

[KB73RR]

Errant nonsense, and no doubt your money will going on a bridge to lurk under...

Ha ha ha - no, bridges are so passe. Carbon nanotube space elevators are the way of the future and much better for lurking under!

[Antice]

Ha ha ha - no, bridges are so passe. Carbon nanotube space elevators are the way of the future and much better for lurking under!

well.. you better be much more patient than Skylon supporters if you are investing in space elevators. Skylon may not be quite ready for the main dev cycle yet. there are still some technology readiness issues, but at least all the puzzle pieces for the skylon is being worked on. no item on the list of need to have for skylon is missing. It's all a matter of incremental development if each component system.

I do not see any benefit in arguing trough the entire list of components needed for skylon however. so if anyone disagrees with the above statement then by all means include what component you are objecting to, and why.

[Antice]

Skylon is featuring on The Register.

They are talking about engine tests in 3 or 4 years if enough funding is appropriated.
Fingers crossed and all that for a successful final push towards a working SABRE engine.

[TrAI]

...

The Wiki article (http://en.wikipedia.org/wiki/Reaction_Engines_SABRE) about the SABRE engine makes some amazing claims. To quote, "The engine gives good fuel efficiency peaking at about 2800 seconds within the atmosphere. Typical all-rocket systems are around 450 at best, and even "typical" nuclear thermal rockets only about 900 seconds." Are they talking about specific impulse or specific thrust or what? Are they claiming efficiencies in the range of ion engines? Then there is the matter of the helium powered turbopumps re-cycling waste heat. Why not do the same using the hydrogen fuel? The helium system just seems like extra mass.

The Skylon user's manual gives the following projected data for the engines on the Skylon C2:
Maximum air-breathing thrust 2 x 1350 kN
Isp in air-breathing mode 35000 N s / kg
Maximum thrust in rocket mode 2 x 1800 kN
Isp in rocket mode 4500 N s / kg

The helium system is in fact one of the improvements in this engine design over earlier precooled designs. These earlier precooler systems using hydrogen tended to become brittle and break as the hydrogen diffused into the metal(a process called hydrogen embrittlement). This would pose a problem to the reliability and rapid re-usability of a craft using SABRE engines.

[Antice]

I've been looking around at other air turborocket concepts lately.
SABRE is a derivative form of air turborocket after all.
SABRE is the only one that uses a closed Helium loop brayton cycle to drive the turbocompressor tho. but there are some fairly distinct advantages to it.
for one they can exploit the hot incoming air to help drive the cycle. this saves on fuel/oxidizer in the preburner that it has in common with Air turborockets. A secondary benefit is that they can get precooling without having to dump coolant into the incoming air-stream like some of the concepts out there plan to do.
The drawback is the extra fuel consumption caused by using the LH2 as a heatsink. RE solved that pretty elegantly by adding ramjet bypass burners to the mix. The engine is actually more efficient the faster it goes. until it reaches mach 5 and max air breathing altitude. there is no good reason for why the engine could not handle even higher speeds. but for an SSTO mach 5 at 26km altitude is about optimal in terms of oxidizer mass saved. any faster and drag losses starts to eat into your propellant budget again. at that point it is more mass economical to nose up and blast direct for orbit in rocket mode.

This is why i think scramjets are useless for orbital launch. scramjet's do force one to stay deeper into the atmosphere for longer than what is sensible. the faster you go the bigger the drag loss one has to overcome.

[RGClark]

...The engine is actually more efficient the faster it goes. until it reaches mach 5 and max air breathing altitude. there is no good reason for why the engine could not handle even higher speeds. but for an SSTO mach 5 at 26km altitude is about optimal in terms of oxidizer mass saved. any faster and drag losses starts to eat into your propellant budget again. at that point it is more mass economical to nose up and blast direct for orbit in rocket mode.
This is why i think scramjets are useless for orbital launch. scramjet's do force one to stay deeper into the atmosphere for longer than what is sensible. the faster you go the bigger the drag loss one has to overcome.

No, if Mach 5 turns out to be the most economical max speed for airbreathing mode, you just do that with a scramjet.

Bob Clark

[NEOWatcher]

No, if Mach 5 turns out to be the most economical max speed for airbreathing mode, you just do that with a scramjet.

And a whole lot more equipment to get the craft up to the speed that a scramjet needs.

[Garrison]

And a whole lot more equipment to get the craft up to the speed that a scramjet needs.

Exactly. Here's a quote from the Wikipedia page on scramjets:

Due to the nature of their design, scramjet operation is limited to near-hypersonic velocities. As they lack mechanical compressors, scramjets require the high kinetic energy of a hypersonic flow to compress the incoming air to operational conditions. Thus, a scramjet-powered vehicle must be accelerated to the required velocity by some other means of propulsion, such as turbojet or rocket engines. In the flight of the experimental scramjet-powered Boeing X-51A, the test craft was lifted to flight altitude by a turbofan powered B-52 before being released and accelerated by a detachable rocket to near Mach 4.5.

And once it get up where the air is too thin it's going to need secondary propulsion, or a separate vehicle, to make orbit. That's one of the pluses of SABRE; one engine from concrete to orbit.

[Antice]

Scramjet's have severe heating issues as well. going faster than mach 6 starts to levy TPS requirements that will compete with that of re-entry. the thermal load is different, in that it is sustained heating instead of short term heating. it's not enough that the aeroshell can stand the temp. the internals will be affected too unless active cooling is used. this is why a hypersonic passenger craft like the LAPCAT has a higher dev risk than skylon. The extra requirements on the aeroshell is going to add dry mass. this mass is directly going to lower payload capability.

The dev risk with SABRE is about to be retired as well. Their future programs director has talked in public about a full up engine demonstration in the 2012 - 2013 time-frame. With all the standard disclaimers about possible delays ofc.

[Garrison]

Scramjet's have severe heating issues as well. going faster than mach 6 starts to levy TPS requirements that will compete with that of re-entry. the thermal load is different, in that it is sustained heating instead of short term heating. it's not enough that the aeroshell can stand the temp. the internals will be affected too unless active cooling is used. this is why a hypersonic passenger craft like the LAPCAT has a higher dev risk than skylon. The extra requirements on the aeroshell is going to add dry mass. this mass is directly going to lower payload capability.

The dev risk with SABRE is about to be retired as well. Their future programs director has talked in public about a full up engine demonstration in the 2012 - 2013 time-frame. With all the standard disclaimers about possible delays ofc.

It can't come soon enough for me!

[Antice]

It can't come soon enough for me!

Yeah. i wanted this like... yesterday.

Something funny tho... when using some back of the envelope estimate for a SSTO based on turborockets i find that even with an ISP of around 2000 sec and air breathing to only mach 3.5 then an isp at the shuttle level for the rest of the trip to orbit gives a marginal positive payload for a vehicle the size of skylon. I'm not going to publish the math i used here, because i am certain I have messed it up somehow. I am not even certain that one can just convert air breathing into ISP in sec just like that.
but if someone with a better grasp on the rocket equation wants a go i would be interested in looking at the methods used.

Another reason I am sceptical of my own result is that turborocket ISP numbers were just something i found on a blog. I havent found any credible sources giving any kind of efficiency numbers on pure turborocket engines. besides. my payload came out higher than what is advertised for skylon when i tried it with the numbers published. I do not know how much of a performance margin they are planning on keeping in reserve to handle weight growth in their plans.

[Garrison]

Yeah. i wanted this like... yesterday.

Something funny tho... when using some back of the envelope estimate for a SSTO based on turborockets i find that even with an ISP of around 2000 sec and air breathing to only mach 3.5 then an isp at the shuttle level for the rest of the trip to orbit gives a marginal positive payload for a vehicle the size of skylon. I'm not going to publish the math i used here, because i am certain I have messed it up somehow. I am not even certain that one can just convert air breathing into ISP in sec just like that.
but if someone with a better grasp on the rocket equation wants a go i would be interested in looking at the methods used.

Another reason I am sceptical of my own result is that turborocket ISP numbers were just something i found on a blog. I havent found any credible sources giving any kind of efficiency numbers on pure turborocket engines. besides. my payload came out higher than what is advertised for skylon when i tried it with the numbers published. I do not know how much of a performance margin they are planning on keeping in reserve to handle weight growth in their plans.

It's possible some of the accurate info just isn't available because it's commercially sensitive, and I suspect some of the older assumptions about turborockets are a little off.

[Antice]

It's possible some of the accurate info just isn't available because it's commercially sensitive, and I suspect some of the older assumptions about turborockets are a little off.

Probably. But turborockets do save tonnes of lox compared to traditional rockets. the penalty is the much lower T/W ratio of these engines compared to rockets. SABRE has a much improved average T/W ratio compared to traditional turborockets tho. It's up by almost 50% compared to older concepts. I suspect the added ramjet has something to do with this. SABRE also has close to 50% better airbreathing ISP than traditional turborocket numbers i could find. but this could be attributed to the precooling technology. it does allow the turborocket part of the engine to use the air much more effectively.
But as you said. turborocket performance numbers are somewhat suspect since nobody has actually flown one and measured the performance in flight.
All the concepts i have seen so far never got past ground testing, and in those cases they were cobbled together from spare parts more or less.
I'm going to try to look a bit more closely at the numbers for several more concepts. but it's kinda hard to get anything really useful from it since the SABRE is so markedly more complex than any other turborocket concept out there. I can just about visualize everything going on in that engine inside my mind if i concentrate really hard.

VASIMR was never this hard to visualize the workings of.

[Antice]

Well. it's that time of the month again. The latest news update from REL is here.

Some highlights: Rel has been in the news as mentioned earlier in this thread. both in the independent and the register. They also had a stand at the farnborough Inernational airshow. Wish i could have been there and pickled some brains, but C'es el a Vie.
Alan Bond has been awarded the degree doctor of engineering as well. I've not heard of many that has gotten such a distinguished title in engineering. I wonder if it will make investors sit up and listen closely when he talks now.

All in all i had hoped to see more news about progress on the Skylon and SABRE. but i guess there cant be much to report every month at this stage in the process.

[RGClark]

Probably. But turborockets do save tonnes of lox compared to traditional rockets. the penalty is the much lower T/W ratio of these engines compared to rockets. SABRE has a much improved average T/W ratio compared to traditional turborockets tho. It's up by almost 50% compared to older concepts. I suspect the added ramjet has something to do with this. SABRE also has close to 50% better airbreathing ISP than traditional turborocket numbers i could find. but this could be attributed to the precooling technology. it does allow the turborocket part of the engine to use the air much more effectively.
But as you said. turborocket performance numbers are somewhat suspect since nobody has actually flown one and measured the performance in flight.
All the concepts i have seen so far never got past ground testing, and in those cases they were cobbled together from spare parts more or less.
I'm going to try to look a bit more closely at the numbers for several more concepts. but it's kinda hard to get anything really useful from it since the SABRE is so markedly more complex than any other turborocket concept out there. I can just about visualize everything going on in that engine inside my mind if i concentrate really hard.

In other words you are estimating the performance of a launch vehicle by switching out the engine for a different engine.

Bob Clark

[Garrison]

In other words you are estimating the performance of a launch vehicle by switching out the engine for a different engine.

Bob Clark

No Bob, Antice's saying that it's hard to estimate the performance of one system based on the performance of another, a fact you seem sadly unable to grasp. Oh and do you get now why your last post:

No, if Mach 5 turns out to be the most economical max speed for airbreathing mode, you just do that with a scramjet.

was just plain wrong?

[RGClark]

Oh and do you get now why your last post:
was just plain wrong?

Actually Antice and I are doing the same thing; we are making an estimate. You won't know what the actual numbers are until you do a full vehicle analysis.
About the scramjet, remember the Skylon also uses turbojet propulsion until the hypersonic airbreathing mode takes over, except that the design of the Skylon is to combine them into a single engine.
But keep in mind that is the intent for scramjet engines as well to combine them into a single engine:

X-43 Hyper-X Program.
"The X-43 program was originally intended to feature two additional vehicles. As envisioned, the X-43B would demonstrate an engine capable of operating in several modes. The X-43B’s combined cycle engine would function as a normal turbojet at low altitudes and switch to scramjet mode at high altitudes and speeds. Planned X-43B flights were to occur sometime in 2009 after the completion of another Hyper-X test vehicle, the X-43C. The X-43C was intended to demonstrate the operation of a solid hydrocarbon-burning scramjet engine at speeds between Mach 5 and 7 sometime in 2008.
"Both vehicles were cancelled in March 2004 because of a shift in NASA’s strategic goals following the announcement of the President’s Vision for Space Exploration in January of that year. However, because of the success of the X-43A , the U.S. Congress added $25 million to the NASA 2005 budget to continue development of the X-43C research vehicle."
http://www.globalsecurity.org/space/systems/x-43.htm

The successful flight test of the long-burning X-51 scramjet would give impetus for this one as well to be transitioned to use combined-cycle propulsion.
Supporters of the Skylon on this forum seem to be taking the view that anyone who supports some other method of low cost space access must be opposed to the Skylon. No, I fully expect and want the Skylon to succeed within 10 years when it is deployed. I also expect scramjet propulsion to succeed in lowering the cost of space access. And I also expect pure rocket, fully reusable vehicles to succeed in cutting the cost of space access.
Having all three of these different vehicle types operating at the same time would serve to increase the competition to further reduce the costs of space access.


Bob Clark

[Antice]

In other words you are estimating the performance of a launch vehicle by switching out the engine for a different engine.

Bob Clark

Yes. with a poorer performing engine. I'm trying to figure out how much of a performance gain they are counting on trough the extra complexity. I'm not trying to make a workable vehicle concept. it's more a matter of getting a feel for the expected benefits gained with the SABRE concepts.
Also it's interesting to see if the HOTOL SSTO case could have been closed earlier with older tech within the same mass limit as the skylon.
I'm not ready to make a judgement on wither it could, The performance numbers for turborockets seem to be as reliable as if i was pulling them out of thin air. Unless more reliable data is obtained I will abandon the attempt as an exercise in futility.

About those under carriages. since mass is at such a premium it makes sense to go to a higher ground pressure, but there is a pretty nasty economic penalty for doing so. needing all that reinforcement in the runway and attending tarmac areas around the support is going to add to the overall costs a bit. On the bright side, if all the airports upgrade we could get to see larger airliners come into use as well. It's kinda like the panamax size limit on container ships.

[Garrison]

The successful flight test of the long-burning X-51 scramjet would give impetus for this one as well to be transitioned to use combined-cycle propulsion.
Supporters of the Skylon on this forum seem to be taking the view that anyone who supports some other method of low cost space access must be opposed to the Skylon. No, I fully expect and want the Skylon to succeed within 10 years when it is deployed. I also expect scramjet propulsion to succeed in lowering the cost of space access. And I also expect pure rocket, fully reusable vehicles to succeed in cutting the cost of space access.
Having all three of these different vehicle types operating at the same time would serve to increase the competition to further reduce the costs of space access.
Bob Clark

No Bob, I simply think you have no clue what you are talking about. The X-43 program was looking to develop an engine that could operate from subsonic to hypersonic velocities and save weight by drawing Oxygen from the atmosphere. Great idea and exactly what the SABRE is designed to do. If you actually read and understood the material you would have realized that the SABRE is the engine NASA wanted to develop, only Reaction Engines are 10-20 years ahead of them.
As for rocket powered SSTO's well that's been argued to death in other threads and if you want to take it up yet again why don't you revive your X-33 thread.

[Garrison]

Yes. with a poorer performing engine. I'm trying to figure out how much of a performance gain they are counting on trough the extra complexity. I'm not trying to make a workable vehicle concept. it's more a matter of getting a feel for the expected benefits gained with the SABRE concepts.
Also it's interesting to see if the HOTOL SSTO case could have been closed earlier with older tech within the same mass limit as the skylon.
I'm not ready to make a judgement on wither it could, The performance numbers for turborockets seem to be as reliable as if i was pulling them out of thin air. Unless more reliable data is obtained I will abandon the attempt as an exercise in futility.

About those under carriages. since mass is at such a premium it makes sense to go to a higher ground pressure, but there is a pretty nasty economic penalty for doing so. needing all that reinforcement in the runway and attending tarmac areas around the support is going to add to the overall costs a bit. On the bright side, if all the airports upgrade we could get to see larger airliners come into use as well. It's kinda like the panamax size limit on container ships.

I suspect there might be one or two places that might gamble on the investment to turn themselves into a major space hub, in the way New Mexico is hoping to with suborbital tourism. I could certainly see somewhere like the UAE making the investment, look at the money Dubai has spent essentially creating a tourist industry from scratch, and a spaceport would be child's play compared to some of the projects in Dubai. It would obviously be a risk but if the Skylon works as advertised the rewards could be huge.