5 is BS: it would be impossible to write concise science papers without using technical language of the field you are in. Jargon isn't to impair communication with the public, its to facilitate the communication between experts, and is vital. Everyday English is for the press releases and popular science magazines.
Whoever wrote this is (willfully or otherwise) ignorant of the driving conditions on UK motorways. Driving at 60mph is basically impossible - you either have to get in the slow line behind the lorries and go slower, or get in the middle or fast lane and drive ~80mph. Yes, the speed limit is technically 70mph. In most part of the country, nobody gives a crap.
So the range is nearly irrelevant; the car is unsuitable for motorway driving so you won't be taking it any distance at all.
The author claims that the French rate of 3/year during the peak of their nuclear building program shows how ridiculous 115/year is; what that fails to account for is that France has 1% of the world population; so such a rate is fine.
Dark matter has many testable predictions; armchair physicists who think they can second guess professionals only ever seem to know about rotation curves, and smugly decide that they know better.
Modified gravity only has the benefit of fitting certain observations - it has no theoretical backing. With most current data, modified gravity doesn't fit that well anyway. Its largely out of favour with physicists, only with those people who think that without any formal training in the subject they understand it better than physicists
No, they think a small increase in temperature might impact global agriculture and thus mean there isn't nearly enough food to feed 10 billion people. Then people start killing each other for food. This fear is justified.
They will be forcibly removed by the US government (and possibly other treaty signatories) who have agreed to preserve Antarctica. You have, quite by accident, highlighted a good reason why a new colony should be on another planet!
Its not about air, or temperature, or soil, its about people.
What Mars gets you is a place that is entirely isolated from the poor folks, from politicians who might restrain you or tax you - you can't even access the Internet as we know it from Mars due to radio lag. Its a societal fresh start.
People making your arguments often say things like "why not colonise the Gobi desert? its much nicer than Mars". Thats actually easy to answer - the Gobi desert is (mostly I think) in China, and I don't want to live under the Chinese government. To have a societal clean slate, you need to go far and you need to live under harsh conditions.
Once more, saving 250t of liquid oxygen is absolutely nothing to do with cost! Its to do with reducing the take off mass - which is what enables the performance required for SSTO.
Oh, and the Space Shuttle wasn't reusable, it was rebuildable.
So let me get this straight; you think you have spotted a major flaw in their design that was not spotted by various governments, space agencies and aerospace companies that have thoroughly analysed this project? Have you done the sums and found that the precoolers have more mass than the oxygen saved? Have you worked out the losses due to drag?
I was talking about integrating stages, not payload. SpaceX still have to and always will have to do that. The TPS isn't magic either They are already talking to manufacturers about how to build it. Most importantly though is due to the aerodynamics of the vehicle it will have a much milder re-entry than the Space Shuttle, only needing the same kind of thermal protection it has in certain critical areas.
And no, SpaceX does not have a reusable vehicle that actually exists. They haven't yet recovered a first stage, never mind reflown one.
Please, could people actually investigate this project, its history and the major players who have invested in it before dismissing it out of hand based on intuition?
Your opinion is based in ignorance then. Costs cannot come down without re-usability and solid rockets are not reusable. The Shuttle SRBs had reusable casing - which had to be separated into segments, refilled with solid fuel, and then put back to together. Ever see an Airbus A320 get chopped into segments between flights?
It never becomes a scramjet. Not being a scramjet is in fact the entire point behind the last few decades of research. You can either try to burn fuel in a supersonic flow through your engine (scramjet) or you can slow the flow to subsonic and compress it so the fuel can burn properly (ramjets etc.) - problem is, this compression superheats the air. SABRE dumps the excess heat into the cryogenic hydrogen the vehicle carries so that you can operate an engine at high Mach number without its insides melting.
As for too many moving parts; they precooler itself does not appear to have any moving parts. It needs a liquid helium cooling loop to connect it to the hydrogen supply, but that isn't overly complex. Everything behind that is well established jet/rocket engine technology. Even if you assume that each precooler + bypass is itself as complicated as enough engine, the spacecraft only has as many "moving parts" as an ordinary rocket with 4 engines. SpaceX happily flies a rocket with 9 engines and will likely be able to reuse its first stage in a cost effective way.
They have worked out their cost/kg and found it to be lower - and had their sums checked by third parties. I have the feeling this project is largely not being taken seriously because Americans don't pay attention to anything outside their borders (and generally refuse to believe any worthwhile advance comes from outside the US)
They have built something. A precooler that can cool incoming air from 1000C to -150C as it comes into an engine intake at Mach 5, and is light and small enough to fit into an aircraft engine. This is the main part of the vehicle that is a big unknown, and they have shown it works in view of experts from government and industry.
Because Reaction Engines are not NASA and its not the 1970s anymore? You seem to be assuming that SSMEs are the cheapest LH2 engines that could ever be made (wrong - see RS-68, RD-0120 etc.) and that NASAs procedures for turning them around are optimal.
SpaceX started with a lot of money behind it, the support of NASA, and they are doing something very conventional (multi-stage LOx-Kerosene rockets) albeit better than the competition. Reaction engines are aiming at what they claim (with good reason) to be the biggest advance in propulsion since the jet engine. Snarky crap on slashdot is quick enough to write; R&D takes a long time.
They have specced billions to get to a flying spacecraft that is ready to be sold to vendors. The money they have got gets them to their next step; a ground test of a full engine. At that point they will be able to unlock more funding as the risk will have gone down. This method has got them this far; they secured funding from BAE and the UK government by demonstrating that the key enabling technology - the precooler - works.
If you think saving money on LOx is in any way the aim of Skylon, you have demonstrated your utter inability to grasp basic rocket science. Its about saving mass; and Skylon does a hell of a lot of that. So much so that (by the estimation of all the third parties who have looked at the design - including the UK government, ESA, DLR and recently the USAF) it can achieve SSTO operation. It takes off and lands like a plane, so no need to integrate it each time. That is an advance on even SpaceX - they have to manufacture a new second stage and attach it to the reusable first stage.
I assume you are talking about the SJWs? Those who will descend like a pack of harpies on anybody who dissents from their ideology, and then when they meet resistance, cry "harassment" and get their friends in various media outlets to write factually incorrect articles claiming that the SJWs victims launched unprovoked attacks on them.
"Lewis' Law" is what is called a Kafkatrap. If you claim that negative responses to your idea validate it, then you have rendered it non-falsifiable; you have essentially quit the field of argument telling yourself you have won - when nothing could be further from the truth.
The Moon is not better than Mars. It has a much harsher thermal environment due to its complete lack of atmosphere. Mars is very cold - but its pretty consistent. The Moon has wild variations in temperature depending on if you are in sunlight or shade - and the night lasts 2 weeks. The first lunar night it had to endure pretty much killed the Chinese moon rover. Non of the Apollo missions spent a night.
The dust on the Moon is entirely un-weathered, and is likely to present a hazard due to being incredible abrasive. Mars dust is probably easier to deal with
The martian atmosphere provides CO2 - that is 2 useful elements you can get just by sucking it through a pump. Any materials you want to use on the Moon must be mined from rocks, and that is harder.
Finally, the Moon is too close. One goal of an offworld colony is a break from lots of the crap here on Earth. A place where you could conceivably still get a connection to Earth internet (albeit with seconds of lag) makes this harder.
Slashdot Mirror
5 is BS: it would be impossible to write concise science papers without using technical language of the field you are in. Jargon isn't to impair communication with the public, its to facilitate the communication between experts, and is vital. Everyday English is for the press releases and popular science magazines.
It may not accelerate fast enough for your liking (unless its been driven by a moron who missed the point) but a Prius will happily do 90mph+
Whoever wrote this is (willfully or otherwise) ignorant of the driving conditions on UK motorways. Driving at 60mph is basically impossible - you either have to get in the slow line behind the lorries and go slower, or get in the middle or fast lane and drive ~80mph. Yes, the speed limit is technically 70mph. In most part of the country, nobody gives a crap.
So the range is nearly irrelevant; the car is unsuitable for motorway driving so you won't be taking it any distance at all.
The author claims that the French rate of 3/year during the peak of their nuclear building program shows how ridiculous 115/year is; what that fails to account for is that France has 1% of the world population; so such a rate is fine.
Dark matter has many testable predictions; armchair physicists who think they can second guess professionals only ever seem to know about rotation curves, and smugly decide that they know better.
Modified gravity only has the benefit of fitting certain observations - it has no theoretical backing. With most current data, modified gravity doesn't fit that well anyway. Its largely out of favour with physicists, only with those people who think that without any formal training in the subject they understand it better than physicists
Bullshit. They don't want to be lynched by angry mobs who just want something to eat. They want to be on another planet when the shit hits the fan.
No, they think a small increase in temperature might impact global agriculture and thus mean there isn't nearly enough food to feed 10 billion people. Then people start killing each other for food. This fear is justified.
They will be forcibly removed by the US government (and possibly other treaty signatories) who have agreed to preserve Antarctica. You have, quite by accident, highlighted a good reason why a new colony should be on another planet!
Its not about air, or temperature, or soil, its about people.
What Mars gets you is a place that is entirely isolated from the poor folks, from politicians who might restrain you or tax you - you can't even access the Internet as we know it from Mars due to radio lag. Its a societal fresh start.
People making your arguments often say things like "why not colonise the Gobi desert? its much nicer than Mars". Thats actually easy to answer - the Gobi desert is (mostly I think) in China, and I don't want to live under the Chinese government. To have a societal clean slate, you need to go far and you need to live under harsh conditions.
"Tankage mass is not generally that expensive"? FFS. Learn the rocket equation before commenting on launch systems, please.
Once more, saving 250t of liquid oxygen is absolutely nothing to do with cost! Its to do with reducing the take off mass - which is what enables the performance required for SSTO.
Oh, and the Space Shuttle wasn't reusable, it was rebuildable.
The existence of failure modes is not a sufficient reason to predict high failure rates.
So let me get this straight; you think you have spotted a major flaw in their design that was not spotted by various governments, space agencies and aerospace companies that have thoroughly analysed this project? Have you done the sums and found that the precoolers have more mass than the oxygen saved? Have you worked out the losses due to drag?
I was talking about integrating stages, not payload. SpaceX still have to and always will have to do that. The TPS isn't magic either They are already talking to manufacturers about how to build it. Most importantly though is due to the aerodynamics of the vehicle it will have a much milder re-entry than the Space Shuttle, only needing the same kind of thermal protection it has in certain critical areas.
And no, SpaceX does not have a reusable vehicle that actually exists. They haven't yet recovered a first stage, never mind reflown one.
Please, could people actually investigate this project, its history and the major players who have invested in it before dismissing it out of hand based on intuition?
Your opinion is based in ignorance then. Costs cannot come down without re-usability and solid rockets are not reusable. The Shuttle SRBs had reusable casing - which had to be separated into segments, refilled with solid fuel, and then put back to together. Ever see an Airbus A320 get chopped into segments between flights?
Wrong on multiple points
It never becomes a scramjet. Not being a scramjet is in fact the entire point behind the last few decades of research. You can either try to burn fuel in a supersonic flow through your engine (scramjet) or you can slow the flow to subsonic and compress it so the fuel can burn properly (ramjets etc.) - problem is, this compression superheats the air. SABRE dumps the excess heat into the cryogenic hydrogen the vehicle carries so that you can operate an engine at high Mach number without its insides melting.
As for too many moving parts; they precooler itself does not appear to have any moving parts. It needs a liquid helium cooling loop to connect it to the hydrogen supply, but that isn't overly complex. Everything behind that is well established jet/rocket engine technology. Even if you assume that each precooler + bypass is itself as complicated as enough engine, the spacecraft only has as many "moving parts" as an ordinary rocket with 4 engines. SpaceX happily flies a rocket with 9 engines and will likely be able to reuse its first stage in a cost effective way.
They have worked out their cost/kg and found it to be lower - and had their sums checked by third parties. I have the feeling this project is largely not being taken seriously because Americans don't pay attention to anything outside their borders (and generally refuse to believe any worthwhile advance comes from outside the US)
They have built something. A precooler that can cool incoming air from 1000C to -150C as it comes into an engine intake at Mach 5, and is light and small enough to fit into an aircraft engine. This is the main part of the vehicle that is a big unknown, and they have shown it works in view of experts from government and industry.
Because Reaction Engines are not NASA and its not the 1970s anymore? You seem to be assuming that SSMEs are the cheapest LH2 engines that could ever be made (wrong - see RS-68, RD-0120 etc.) and that NASAs procedures for turning them around are optimal.
SpaceX started with a lot of money behind it, the support of NASA, and they are doing something very conventional (multi-stage LOx-Kerosene rockets) albeit better than the competition. Reaction engines are aiming at what they claim (with good reason) to be the biggest advance in propulsion since the jet engine. Snarky crap on slashdot is quick enough to write; R&D takes a long time.
They have specced billions to get to a flying spacecraft that is ready to be sold to vendors. The money they have got gets them to their next step; a ground test of a full engine. At that point they will be able to unlock more funding as the risk will have gone down. This method has got them this far; they secured funding from BAE and the UK government by demonstrating that the key enabling technology - the precooler - works.
If you think saving money on LOx is in any way the aim of Skylon, you have demonstrated your utter inability to grasp basic rocket science. Its about saving mass; and Skylon does a hell of a lot of that. So much so that (by the estimation of all the third parties who have looked at the design - including the UK government, ESA, DLR and recently the USAF) it can achieve SSTO operation. It takes off and lands like a plane, so no need to integrate it each time. That is an advance on even SpaceX - they have to manufacture a new second stage and attach it to the reusable first stage.
I assume you are talking about the SJWs? Those who will descend like a pack of harpies on anybody who dissents from their ideology, and then when they meet resistance, cry "harassment" and get their friends in various media outlets to write factually incorrect articles claiming that the SJWs victims launched unprovoked attacks on them.
"You are all childish and petty"
"You smell and girls don't like you!"
No points for self awareness here.
"Lewis' Law" is what is called a Kafkatrap. If you claim that negative responses to your idea validate it, then you have rendered it non-falsifiable; you have essentially quit the field of argument telling yourself you have won - when nothing could be further from the truth.
The Moon is not better than Mars. It has a much harsher thermal environment due to its complete lack of atmosphere. Mars is very cold - but its pretty consistent. The Moon has wild variations in temperature depending on if you are in sunlight or shade - and the night lasts 2 weeks. The first lunar night it had to endure pretty much killed the Chinese moon rover. Non of the Apollo missions spent a night.
The dust on the Moon is entirely un-weathered, and is likely to present a hazard due to being incredible abrasive. Mars dust is probably easier to deal with
The martian atmosphere provides CO2 - that is 2 useful elements you can get just by sucking it through a pump. Any materials you want to use on the Moon must be mined from rocks, and that is harder.
Finally, the Moon is too close. One goal of an offworld colony is a break from lots of the crap here on Earth. A place where you could conceivably still get a connection to Earth internet (albeit with seconds of lag) makes this harder.