Skylon
Join Date: Apr 2008
Location: The Whyte House
Age: 95
Posts: 1,966
Likes: 0
Received 0 Likes
on
0 Posts
Mix any fuel and oxidiser and the risks are the same, I'd hazard a guess that the result of the o-ring failure would have been similar had RP-1 been used instead. Atlas had several launch pad failures using the very same kerosene derived propellant.
LH2 & LOX seemed to work okay in the second and third stages of the Saturn V rocket.
LH2 & LOX seemed to work okay in the second and third stages of the Saturn V rocket.
It's stupid of me to bite but just FYI that picture is of the Challenger explosion and "Disintegration of the vehicle began after an O-ring seal in its right solid rocket booster (SRB) failed at liftoff." So the carrying of hydrogen + oxygen was not the cause of the accident and, presumably, the event would have been fatal with or without the main fuel tank.
It's really the ability to operate repeatedly like an aeroplane without throwing bits off that makes Skylon of interest - it can be tested progressively and each flight is not a from-scratch untested vehicle. Mr Varville said in his talk that the failure rate of rockets is about a million times more than that of a civil aircraft. The idea of Skylon is to bring space launch closer to that civil aircraft reliability. So essentially if you want to see more explosions then by all means carry on launching expendable rockets.
It's really the ability to operate repeatedly like an aeroplane without throwing bits off that makes Skylon of interest - it can be tested progressively and each flight is not a from-scratch untested vehicle. Mr Varville said in his talk that the failure rate of rockets is about a million times more than that of a civil aircraft. The idea of Skylon is to bring space launch closer to that civil aircraft reliability. So essentially if you want to see more explosions then by all means carry on launching expendable rockets.
Best of luck to them, and I hope they keep trying until they succeed - explosions or not.
Aerospace is so bleedin' boring at the moment.
When did everyone become so frickin risk averse and cautious...!
Aerospace is so bleedin' boring at the moment.
When did everyone become so frickin risk averse and cautious...!
Join Date: Mar 2009
Location: Perth Western Australia
Age: 57
Posts: 808
Likes: 0
Received 0 Likes
on
0 Posts
It's stupid of me to bite but just FYI that picture is of the Challenger explosion
.The shuttle itself, never had any failures on its own accord, the shuttle system on the other hand
.Liquid hydrogen and Oxygen is the go, the Venture star was going to be powered them. It would have been interesting to see how that went if it wasn't for the tank issues.
Join Date: Oct 2002
Location: ɐıןɐɹʇsn∀
Posts: 1,994
Likes: 0
Received 0 Likes
on
0 Posts
I'd normally bite to that rh200, but my dear old dad always told me that it's considered unfair to engage in a battle of wits against an unarmed man..
For the rest of you, I'm fully aware that the photo is of the space shuttle, and yes, rockets are fueled with an oxidiser and a propellant. It's the suggestion that the engines may be used in a passenger craft that inspired my post. If you are happy paying for a trip on a flying bomb put together by the lowest bidder though, fill ya boots!
As Danny42C said, "you won't be getting me on one of those things!', I'll take my chances with Jet A1 thanks
For the rest of you, I'm fully aware that the photo is of the space shuttle, and yes, rockets are fueled with an oxidiser and a propellant. It's the suggestion that the engines may be used in a passenger craft that inspired my post. If you are happy paying for a trip on a flying bomb put together by the lowest bidder though, fill ya boots!
As Danny42C said, "you won't be getting me on one of those things!', I'll take my chances with Jet A1 thanks
For the rest of you, I'm fully aware that the photo is of the space shuttle, and yes, rockets are fueled with an oxidiser and a propellant. It's the suggestion that the engines may be used in a passenger craft that inspired my post. If you are happy paying for a trip on a flying bomb put together by the lowest bidder though, fill ya boots!
https://spiral.imperial.ac.uk:8443/b...ar_5_08_03.pdf
Last edited by t43562; 16th Apr 2015 at 13:49. Reason: clarify
It wasn't the LOX/LH2 mix that caused the trouble in the first place, however...
Interesting AFRL comments. I recall one enthusiast for air-breathing access to space remarking that a rocket climbing through the atmosphere was like a fish using scuba gear.
Interesting AFRL comments. I recall one enthusiast for air-breathing access to space remarking that a rocket climbing through the atmosphere was like a fish using scuba gear.
t43562
Thanks for the linked document. The "suitable airframe" upon which to mount the Scimitar (once a couple of the other issues get resolved in further R & D) would need some significant safety factors applied to things like cabin pressurization and seals, for FL's where it looks to be during cruise at Mach 5. (FL~ 800? based on Table 2)
Thanks for the linked document. The "suitable airframe" upon which to mount the Scimitar (once a couple of the other issues get resolved in further R & D) would need some significant safety factors applied to things like cabin pressurization and seals, for FL's where it looks to be during cruise at Mach 5. (FL~ 800? based on Table 2)
Yes - very interesting paper with lots of lovely algebra.
And the two most interesting lines - right at the end:
The engine poses several design and development challenges in intakes, heat exchangers and nozzles, although none of these require fundamental breakthroughs in technology for their realisation.
Apart from the issue of
NOx formation the engine is considered a practical development from known technology.
And the two most interesting lines - right at the end:
The engine poses several design and development challenges in intakes, heat exchangers and nozzles, although none of these require fundamental breakthroughs in technology for their realisation.
Apart from the issue of
NOx formation the engine is considered a practical development from known technology.
Ecce Homo! Loquitur...
If fully developed, it would be a vehicle that could, almost daily, re-fuel and pop a payload into LEO. That thing might not be very big, but getting up there would be very cheap
Clyde Space
Join Date: Jan 2001
Location: Home
Posts: 3,399
Likes: 0
Received 0 Likes
on
0 Posts
Space X
The brief history of SpaceX is illuminating.
Too Cheap To Re-Use
Their original goal was to make a disposable launcher so cheap that it didn't matter that it got thrown away. They did some clever engineering in support of this. For example, their rocket engine bells were made by making two skins about the right shape and crimping them together to form the cooling channels.
This is far quicker and easier than brazing together miles of tubing as was done for the Saturn V's F1s.
Ok, Gonna Have to Re-Use
However their more recent move towards attempting to recover the first stage for re-use suggests that they may not have managed to make the manufacturing cheap enough.
Need to Spend More on QC
Their most recent failure seems to be entirely down to inadequate quality control. A strut, bought from a supplier, did not have the required strength (and nor did some others still on the shelf), and a helium tank broke loose and compromised the structural integrity of the quiescent second stage.
This is entirely down to inadequate quality control on the part of their supplier, and an inadequate quality assurance process within SpaceX. The only way of fixing that is more process.
Add That All Up...
Add this all together and it stacks up to a business that is gradually learning why the government programs were so darn expensive. Getting every component exactly right every time is a ferociously expensive business.
Skylon
I'm far from convinced that efforts like Space X can make truly large cost savings in the satellite launching business. Arianne is highly reliable, long lived, and goes off regular as clockwork. If Ariannespace haven't yet (they've had plenty of time) managed to make their ordered-to-launched process as cheap as possible then I don't know who can. And they use solid boosters too, which is a massive cost saving over liquid fuelled rockets.
Skylon is a completely different proposition, and is about the only idea out there that doesn't involve manufacturing something large and expensive every time it's launched. If it costs something like £20million or less to launch it, it's a going concern.
Plus it would be one hell of a ride. I'm game!
Too Cheap To Re-Use
Their original goal was to make a disposable launcher so cheap that it didn't matter that it got thrown away. They did some clever engineering in support of this. For example, their rocket engine bells were made by making two skins about the right shape and crimping them together to form the cooling channels.
This is far quicker and easier than brazing together miles of tubing as was done for the Saturn V's F1s.
Ok, Gonna Have to Re-Use
However their more recent move towards attempting to recover the first stage for re-use suggests that they may not have managed to make the manufacturing cheap enough.
Need to Spend More on QC
Their most recent failure seems to be entirely down to inadequate quality control. A strut, bought from a supplier, did not have the required strength (and nor did some others still on the shelf), and a helium tank broke loose and compromised the structural integrity of the quiescent second stage.
This is entirely down to inadequate quality control on the part of their supplier, and an inadequate quality assurance process within SpaceX. The only way of fixing that is more process.
Add That All Up...
Add this all together and it stacks up to a business that is gradually learning why the government programs were so darn expensive. Getting every component exactly right every time is a ferociously expensive business.
Skylon
I'm far from convinced that efforts like Space X can make truly large cost savings in the satellite launching business. Arianne is highly reliable, long lived, and goes off regular as clockwork. If Ariannespace haven't yet (they've had plenty of time) managed to make their ordered-to-launched process as cheap as possible then I don't know who can. And they use solid boosters too, which is a massive cost saving over liquid fuelled rockets.
Skylon is a completely different proposition, and is about the only idea out there that doesn't involve manufacturing something large and expensive every time it's launched. If it costs something like £20million or less to launch it, it's a going concern.
Plus it would be one hell of a ride. I'm game!
Last edited by msbbarratt; 11th Nov 2015 at 20:20.
Join Date: Mar 2010
Location: UK on a crosswind
Posts: 262
Likes: 0
Received 0 Likes
on
0 Posts
MSBB got it right "Getting every component exactly right every time is a fericiously expensive business." But good engineering used to be what we could do ....... at least we could design it right. From what I've read of Reaction they seem to be going about this the right way, slowly stage by stage, getting each stage perfectly right, bringing as much in house as possible so as to keep quality control in their own hands. They can certainly seem to do the engines. Now if only we had a decent airframe manufacturer in the country who could begin the design process, this project might actually work.
Small steps is indeed the best way to go. They haven't got an infinite pot of cash, and spending it on the bit that really matters has paid off; they've got more investment :-)
Britain's history in the space business is accidentally quite good.
We had a rocket, called it Blue Streak, meant if for use as an ICBM / deterrent but then realised it was obsolete before it ever came anywhere near going into service. Apparently we gave the whole lot to the French as a "please let us in the EEC" bribe. The French said merci beaucoup, pizouf, and now they have Ariannespace.
Disaster? Big opportunity missed? Perhaps, but not as big as all that.
I don't think anyone has ever made a lot of commercial cash running a launcher. Mainly the motivation is to get a capability for national security reasons. Ariane did that for the French, we did that another way.
Instead we concentrated on satellite building. There's the sites in Portsmouth, Stevenage, Guildford, bits 'n' pieces at the Rutherford Appleton labs, etc. Building satellites has proved to be highly profitable.
If Skylon ever gets anywhere, we (the UK taxpayer) have a stake in it. Sending up lots of payloads that can then be in-orbit assembled is ultimately more impressive than trying to launch all in one go (e.g. the International Space Station). "Impressive" can turn into big money, maybe.
Britain's history in the space business is accidentally quite good.
We had a rocket, called it Blue Streak, meant if for use as an ICBM / deterrent but then realised it was obsolete before it ever came anywhere near going into service. Apparently we gave the whole lot to the French as a "please let us in the EEC" bribe. The French said merci beaucoup, pizouf, and now they have Ariannespace.
Disaster? Big opportunity missed? Perhaps, but not as big as all that.
I don't think anyone has ever made a lot of commercial cash running a launcher. Mainly the motivation is to get a capability for national security reasons. Ariane did that for the French, we did that another way.
Instead we concentrated on satellite building. There's the sites in Portsmouth, Stevenage, Guildford, bits 'n' pieces at the Rutherford Appleton labs, etc. Building satellites has proved to be highly profitable.
If Skylon ever gets anywhere, we (the UK taxpayer) have a stake in it. Sending up lots of payloads that can then be in-orbit assembled is ultimately more impressive than trying to launch all in one go (e.g. the International Space Station). "Impressive" can turn into big money, maybe.
I attended a RAeS talk given by Alan Bond, from HOTOL to SABRE, or something similar.
I was somewhat captivated by the concept of HOTOL as a student, but he, having been there and done it, was less so. According to this talk, it would never have worked.
It's clear that Skylon, or in fact any other mooted system is a way of keeping people interested in REL. The only interest is in developing the SABRE engine, and I think that that is completely the right thing to do.
If there was to be any serious work on a practical application, I would prefer to see work on a vehicle that can crack the ground-to-space tourism and science nut whilst building experience with the engine. This is a much more practical goal whilst providing a useful service, and experience. Whilst that is going on, there should be some work done on making a Skylon/commercial vehicle that can operate off existing runways. I'd love to see the system operate out of Fairford.
I was somewhat captivated by the concept of HOTOL as a student, but he, having been there and done it, was less so. According to this talk, it would never have worked.
It's clear that Skylon, or in fact any other mooted system is a way of keeping people interested in REL. The only interest is in developing the SABRE engine, and I think that that is completely the right thing to do.
If there was to be any serious work on a practical application, I would prefer to see work on a vehicle that can crack the ground-to-space tourism and science nut whilst building experience with the engine. This is a much more practical goal whilst providing a useful service, and experience. Whilst that is going on, there should be some work done on making a Skylon/commercial vehicle that can operate off existing runways. I'd love to see the system operate out of Fairford.
Last edited by unmanned_droid; 12th Nov 2015 at 23:40. Reason: mooted/muted stupidity
It's clear that Skylon, or in fact any other muted system is a way of keeping people interested in REL. The only interest is in developing the SABRE engine, and I think that that is completely the right thing to do.
Hence Skylon isn't necessarily their business and the end vehicle might be different, but it seems to me that there would need to be a very good reason for ignoring it altogether.
Regards,
Tim
Whilst I agree that you need some parameters to play to, that can be limited to a thrust class, and a flight profile to design the engine.
I can't see that the quad engine pod used on the Skylon is designed around the precooler requiring 4 units, although I'm not involved with REL, so not fully aware of the situation.
I deleted a sharp comment about getting the technology thoroughly checked out by AFRL...
I can't see that the quad engine pod used on the Skylon is designed around the precooler requiring 4 units, although I'm not involved with REL, so not fully aware of the situation.
I deleted a sharp comment about getting the technology thoroughly checked out by AFRL...
Too complicated. Might be some (mostly) air-breathing gas-turbine SST related potential in the technology, but not wing borne-to-rocket orbital flight with one type powerplant. Even if it could ever work, what is the problem with using an extra 250 tons of LOX? The foreseable future must be with more reusable, mature, reliable, rockets launching one-way loads or spaceplanes.
OAP
OAP
Having read a lot of the blurb and seen the talks too, my understanding is that there's no point creating an engine without having a feasible concept spaceplane to stick it on otherwise how would you know what the engine should look like, how big it should be, whether it could actually get something into space?