More Eu funding to be renegotiated
Right, so where does the funding for this come from after article 50?
The makers of the newfangled Synergetic Air-Breathing Rocket Engine (SABRE) have secured the necessary funding to fire up their hardware by 2020. Reaction Engines – the Oxfordshire, England-based team behind the next-gen engine – signed a collaboration contract with the European Space Agency at the Farnborough Air Show on …
All the money is coming from the UK government. The ESA is just on board to oversee the administration of part of it. Like a startup bringing in managers approved by investors. The UK gov bankrolls the project knowing that clever folks at ESA will be overseeing part of it as well as the UK Space Agency.
"The ESA is just on board to oversee the administration of part of it. [...] The UK gov bankrolls the project knowing that clever folks at ESA will be overseeing part of it ... "
<ukipmode> Aha! EUcrats controlling a British programme again! </ukipmode>
"All the money is coming from the UK government."
<sarc>All that money being wasted on science and the future when Government agencies are going begging for the billions they need to spend on IT projects to cancel after the proper pockets are lined. It's an outrage I tell ya! *sputter* *fume*<sarc>
"The European Union (EU) and ESA share a common aim: to strengthen Europe and benefit its citizens. While they are separate organisations, they are increasingly working together towards common objectives. Some 20 per cent of the funds managed by ESA now originate from the EU budget. "
NASA needs to spend less cutting many bureaucrats that burdens it - spending those money in researches. The amount of funding of the old days won't return - they need to spend smarter and look further. And ask supplier to be innovative, not to repurpose old designs. Musk is more innovative than Boeing, Lockheed & C.
Getting to the Moon or Mars won't have any beneficial impact unless the technology to achieve it is really innovative and cheaper. We've been already on the Moon with 1960s then "innovative" technology.
Returning there with the same one - but maybe faster computers - is quite useless, but for some political propaganda.
Reaching Mars more so. A one-off mission to state "we got there fist!" may be feasible, but then? Once you burned a lot of old technology to get there, what's the advantage? Some place in history books?
First, I'm hopeful about SABRE. If it works, then it's a new tool in aerospace engineers' tool kits. Further, if Skylon works, then congratulations are in order. Skylon's taking about the most painful possible path to orbit and the engineers who make it work deserve a pint hoisted in their honor. Speaking of simpler approaches:
.... same old engine technology, but it will have touch screens (and maybe apps as well)!!!
Neglecting the specific improvements to the SLS's engines compared to their Shuttle, Saturn, and Centaur predecessors, there's something to be said for simple chemical rocket engines and vertical takeoff.
Consider a single stage to orbit vehicle like Skylon, DC-X, VentureStar, SASSTO, Kankoh Maru, and so on. However you get your SSTO into orbit, you're basically building it to work one both ends of the rocket equation. You can manipulate specific impulse or you can manipulate the mass ratio, or you can try both.
Delta-V (change in velocity) = Specific Impulse x G x natural log (launch mass / final mass)
Short of getting plutonium involved rocket motors tend to top out at a specific impulse of 460 if you're running on hydrogen-oxygen propellants, and most rocket propellants end up in the 300 to 350 range. SABRE and assorted scramjets push into the realm of thousands (perhaps 3500 for SABRE) while they're got external air to supply oxidizer and much of their reaction mass.
The mass ratio of rockets, their fully fueled mass divided by mass upon reaching orbit, tends to be a bit overlooked. Many designers of rocket-based SSTOs consider it impossible to get past a 10:1 ratio, while airplane designers rarely achieve so much as 5:1. Given the impact of a natural log function on any ratio stuffed into that end of the rocket equation and you're better off focusing on specific impulse. The problem is, the mass of your SSTO shouldn't be ignored. There are some design decisions that thoroughly bork your hopes of getting into orbit in a single bound.
For example, SABRE is predicted to have a thrust-to-weight ratio of 14:1. (That's for the engine alone, not the rest of the spacecraft.) By many counts, that's good - better than most military afterburning turbojets (~10:1), and much better than scramjets (~1:2 or worse). But it sets a bound on Skylon's mass ratio, which will never be better than 14:1.
Meanwhile, those same old rocket engines can get 75:1 (like the RS-25 shuttle main engine, which is limited by its low density hydrogen fuel), 100:1 (for the overbuilt F-1 Saturn V engine), to 150:1 (for the Merlin 1D).
Another factor are structural details of your reusable SSTO, like fuel tanks. Your SSTO is going to be carrying this dead weight from the ground to orbit, so it's going to set a floor on the mass ratio. Denser propellants (like liquid oxygen and kerosene) may have tankage less than 3% of the mass they enclose, while hydrogen and to a lesser extent methane are considerably heavier at 7 to 10% of the mass they enclose. (The driving factor in tankage is internal pressurization and volume, not fuel mass, and low density propellants need high pressurization to suppress cavitation at pump intakes.)
Liquid hydrogen, in particular, is a pain to store. Look at the shuttle's external tank: 100 tons of liquid hydrogen occupied 2/3 of its volume and required 1/2 of its mass, while 600 tons of liquid oxygen occupied the small nose section and 1/3 the mass. (The balance was in the intertank connector and other features. Yes, those values are approximate.)
Liquid hydrogen embodies the worst of many features of a propellant for an SSTO: its tanks will necessarily have a high surface area per unit mass because of its low density, which adds to tankage mass, and it needs more pressurization for its pumps, which requires thicker tankage walls. I believe the shuttle ET favored about 15psi in the hydrogen tank.
Liquid oxygen, at 16 times the density of liquid hydrogen, is much more manageable in terms of volume, tank mass, and tank pressurization. Some rocket motors need scarcely 1-2psi pressurization to get good LOX feed.
Earlier, I mentioned that rocket-based SSTO designers considered a 10:1 mass ratio a practical limit. However, they were all considering hydrogen-oxygen rockets. The situation suddenly changes when you replace hydrogen with a denser fuel, like kerosene. Flown, operating hardware like the Saturn V's first stage, the Saturn IC, and the Atlas balloon stages achieved well above 10:1, like 15:1 and were headed for 20:1. (Obviously, they lacked reusable features like heat shields and landing systems.)
You get the best of multiple worlds with dense propellant vehicles: the tanks are lighter and the engines have higher thrust ratios (thrust being limited by fuel entering the combustion chamber, and fuel pump horsepower being determined by pumped volume - a hydrogen/oxygen engine is thus lucky to get to 75:1, while a kerosene/oxygen has no trouble reaching 120:1 or better.) The more compact tanks for a given delta-V also means lighter heat shielding and lighter landing systems.
An interesting point about rocket-based SSTOs is that the initial fuel mass doesn't matter that much. You're burning it all on the way orbit, after all. Only the residual structural details - engine mass, tankage mass, heat shield mass - that were influenced by propellant mass matter.
So, how that all apply to Skylon and SABRE?
Well, what Skylon is doing is:
1) Trying to dramatically increase the specific impulse by using using an airbreathing engine for much of its flight (good idea)
2) Trying to minimize carried oxygen mass, which doesn't win you much
3) Retaining a full amount of liquid hydrogen, with problems discussed above
4) Being very aerodynamic, which penalizes you with elevated surface-to-volume ratios and more structural dead weight
5) Using engines of relatively low thrust-to-weight ratio
6) Using a horizontal takeoff, which requires extra structure to hold the maximum mass of the vehicle along an axis different than its main thrust axis - the single main load direction of a rocket is simpler
Skylon is making a lot of design choices that hinder its final mass ratio. Not necessarily to the point even SABRE won't help, but there's a lot of easy design options being tossed out in favor of the harder path forward. So congratulations are definitely in order if Skylon's engineers make it work.
Meanwhile, the same old NASA technology does work, and does loft a large payload. The mass ratios needed for a rocket-based SSTO have also been proven in flight. If you don't muff it up by taking a difficult path, like Lockheed's VentureStar, reusable SSTOs aren't out of the question with that same old technology.
"Neglecting the specific improvements to the SLS's engines compared to their Shuttle, Saturn, and Centaur predecessors, there's something to be said for simple chemical rocket engines and vertical takeoff."
Yes: They're not as good as a Lofstrom loop, but we don't have any Lofstrom loops.
"Skylon is making a lot of design choices that hinder its final mass ratio."
Skylon is designed to get people and biological fragiles safely to orbit and return them - safely.(*)(**)(***)
If you want heavy lifting then call in a Falcon XX heavy.
Assuming one device will be used for all loads was what turned shuttle into a fustercluck.
(*) The vibration that launch loads are subjected to would literally liquify passenger brains if they weren't sat in expensive well-padded, vibration isolated seats, mounted on more vibration isolation and shock absorbers.
(**) It's also the basis of a "skipper" for rapid longhaul flights (think of a stone skipping on a pond and visualise an aircraft which does the same thing, dipping into the atmosphere to light the engines and provide more thrust). 90 mins to 2 hours to Australia is good, as the vomit inducing ride would likely make anything longer completely intolerable.
(***) Being bunged in a capsule which returns to the ground the way soyuz or dragon do might work, but it's not "safe" and it's certainly not what most revenue-paying passengers will put up with.
Finally, a technical comment. I'm sorry to disappoint the 17 upvoters but this claim needs to be fully backed by a working model at working speeds and simulated altitudes. This hasn't been nearly done, and I don't believe it will ever happen. I don't even know of any supercomputer modelled device that validates the physics of its fundamental aspects. I suspect SABRE is delusion, no matter how many prestigious experts put their imprimatur on it.
They have already run the pre-cooler at ground level (four years ago), so some testing has been done already. (Note that they heated the incoming air up to the temperatures they're expecting at Mach 5).
To my mind this shows that they have demonstrated a working model at working speeds and simulated altitudes, and given that ESA have signed off on the testing so far, they agree. And they, after all, are rocket scientists.
Anyone old enough to remember HOTOL? https://en.wikipedia.org/wiki/HOTOL That ended well (and made me decide to curtail my budding career in aerospace engineering)... Fingers crossed for a bit more progress with this beast!
On a positive note, all those "artist representations" of what HOTOL might look like are now getting a second airing with the new SABRE branding.
It does seem to have been a long time coming, I agree, almost to the point of feeling like vapourware, I too have read about Reaction Engines, Sabre and Skylon, for well over a decade, without seeing much progress.
However, I think that is probably due to a lack of funding, rather than issues with the underlying technology, and as we all know, trying to secure funding from the British government for any sort of technology that doesn't involve the BAE Systems pork barrel is doomed to failure.
"made me decide to curtail my budding career in aerospace engineering"
That's a shame. I worked in aerospace engineering and it was the best couple of decades in my life. Despite the cutbacks and the dearth of new projects interesting work is still being done by interesting people. Some of those who had to leave have gone on to have careers in general and commercial aviation, F1 racing, mainstream car design and "exotic" engineering projects like SABRE, UAVs and even <shudder> delivery drones.
HOTOL had to be redesigned as SABRE when they realised that putting the engines at the back was a bad idea due to the change of weight distribution as the fuel burned up. SABRE has the engines in the middle of the fuselage.
I fondly remember an official illustration of what HOTOL would look like - the artist had even included painting in the ship's name on the fuselage. It was, of course, Anastasia.
@Ian 7 - it's the same people behind Sabre/Skylon - now having benefitted from their experience on the HOTOL project. There were stability problems with HOTOL due to the siting of its engines - Skylon sites its engines differently to solve this problem. getting the precoolers to work without icining up was, apparently, the biggest hurdle they had to overcome with the engine, and they seem to have got that one sorted. So far as I can see, pretty much all they need now is the backing to get a fully working prototype built - which, much to my surprise (given it was the government that halted progress back in HOTOL days), they now seem to be getting.
This could be a very big deal. OK, so it won't lift as much to orbit as SpaceX's boosters, but the entire thing is recoverable. This could make it the vehicle of choice for lighter/compact cargo and crew delivery, with SpaceX and others handling the heavy lift side of things.
It could, potentially, scupper Ariane, unless Ariane develops or licences booster fly-back technology.
IIRC Hotol was to be launched from a sled and ramp system, shades of Fireball XL5. I think It was also tied up in all sorts of politicking and budget issues within Rolls Royce the MOD.
I just hope that Alan Bond & friends are left alone to concentrate on the enginneering of SABRE and the various vehicles. The last thing they need now is a bunch of poiliticians or accountants poking their noses in,
This project is straight out of a Dan Dare comic, and all things being equal should have been lost to the world when HOTOL was scrapped.
.... but this group of visionary engineers didn't give up. They decided to go it alone.... and succeeded.
That's the WOW!
The story is awesome, the characters in it are awesome, and the space plane is going to be truly awesome.
I just cannot wait.
.... but this group of visionary engineers didn't give up. They decided to go it alone.... and succeeded.
That's the WOW!
I just found out that similar happened with Tommy Flowers. Initially he was sent away with a flea in his ear but built the prototype Colosus anyway, his team working unpaid overtime and with a 1940's value of £1000 of his own money.
Died penniless in an old peoples home.
Turin got all the credit.... but he too was shafted by the state.
Yes... these guys have succeeded against all the odds.... but still I look at the investment figures and wonder if they are developing the next generation of rocket propulsion on a shoe string.
Great that they can do this, but I do question whether this project has received the full support that it deserves.
You mention Tommy Flowers..... but let's not forget Frank Whittle.
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