The problem is (and long has been) the degree to which we've tended to believe the printed word, no matter the source. The Internet's gradually improving that situation.
Yah - we've moved from believing the printed word, regardless of source to believing the digital word - but only from sources that we agree with.
I live in Venice, well in the hinterland of it. As you may know, it's a city build "on" the water. The area suffers from geological bradyseism (sinking) of few centimeters per year. It's an irreversible process, simply leading to a worse situation as time goes by.
The city suffers an average of 50 floodings per year, with peak heigth of the water of more than a meter in the lower zones. "Just" 40 years ago, the count of floodings per year was less than a dozen. Lots are the analysis, conferences and general discussion on which should be best ways to limit the effects of such situation. Well, the most common answer is: there's no solution.
There is a solution - one the Venitians practiced for centuries. When the water reaches floor of a building - tear the sucker down, raise the foundation, and build a new one.
Venice's problems aren't caused by global warming nor by geology. They stem from a decision in the 1800's to freeze the city in time as a tourist attraction.
Long term: I think a massive public works project will come out of this. Something along the lines of the Netherlands Delta Works Project. Only on a much more massive scale.
There has been such a massive public works program going on for over a century. The Mississippi is constrained by a massive system of levees, dams, flood control channels, etc... etc... The Netherlands Delta Works Project is little more than a scale model of this system. (In total volume, the levees along the Mississippi river and it's tributaries considerably exceed that of the Great Wall.)
Something along the lines of a massively huge dike between New Orleans and the ocean.
Such a dike would be a waste of time and money - as the main threat to New Orleans is the Mississippi River and Lake Pontchartrain. (It's breaks in the levee that protect the city from the latter that are currently flooding the city.)
The head chef of the Fat Duck (a British restaurant voted the best in the world this year - jokes about British cuisine now null and void)
Not particularly - as the menu of the Fat Duck owes almost nothing to British culinary traditions. It's all French, Nouvelle and Moderne.
If you go back to the Victorian Era, you'll find a rich and diversified British cuisine - but a century that includes massive industrialization, WWI, the Great Depression, WWII (and the austerity that followed) and a massive demographic shift from rural to urban has all but wiped it from living memory. Frankly, after studying food and cooking for nearly two decades - of all the world, the British are the most ignorant of their own food heritage. Even my fellow Americans as McBrainwashed as they are have a dim idea that there are regional cuisines and dishes.
Not all of the impact tests produced holes, and it is unknown whether the foam impact would have busted a new RCC panel.
Try reading and understanding - rather than just cut/paste/highlight what seems to support your supposition.
To wit:
"F3.8-2 The wing leading edge Reinfoced Carbon-Composite material and associate support hardware are remarkably tough and have impact capabilities that far exceed the minimal impact resistance specified in their original design requirements. Nevertheless, these tests demonstrate that this inherent toughness can be exceeded by impacts representative of those that occured during Columbia's ascent."
You also need to understand that a hole is not needed to destroy the Shuttle - a significant divot will do, as will a good sized crack.
But it's clear aging is important to the material properties of the RCC
Certainly. It's also clear that the CAIB found no evidence that ageing effects played a role in the accident - had they felt it worth testing, it would have been tested. The bolded statement above directly indicates that they felt it not to be needed - as large impacts exceed the specifications of a new panel.
I can find no evidence that the CAIB concluded, as you say, that ageing played "no" role, and plenty of at least indirect evidence to the contrary, that they believed ageing did play a role,
They performed extensive analysis and testing of everything they felt might have played a role - and ageing effects are absent from that analysis and testing. Indirect evidence shows it to be a concern, but that they did not feel it played a role. In addition, had they felt it played a role, it would have been in the Findings, which it was not.
Recall the RSS panels on the Space Shuttle, which failed in Columbia and in the CAIB test under surprisingly small impacts. This is not, I think, because the original engineers had their heads up their asses and didn't design for an impact with a bird or some such. I suspect it's because these composite parts are now 25 years old, and subtle changes due to aging have ruined their original design impact resistance, and have opened up unsuspected new failure modes.
You may suspect that - but you'd be wrong. The CAIB report concluded that the foam impact (that lead to the destruction of Columbia) far exceeded the impact specifications for a new panel - ageing effects played no role.
First of all, your "it's ballistics" comment is baiting, OT, and just plain silly.
No, it's plain and simple fact.
Secondly, as at least one person adroitly pointed out, all you have to do is first dissipate your horizontal velocity, and then point your "retro" thrust straight down (down being a relative term, of course) until your alititude is low enough that terminal velocity takes care of your "32 ft/sec^2". (Then you can use parachutes or whatever else you please.)
Sure. When you have unobtanium I-beams to support your handwavium tank walls - I.E. it's not likely with any reasonable technology because of the vast size and weight of the fuel/oxidiser tankage required.
Or heck, use the Roton method and chopper it in! Voila! Zero heating. (Or near enough zero for the point I am making.)
Except - that's not how Roton re-entered. It encountered considerable heat, and had a heat shield to absorb it. The chopper blades didn't engage until it was pretty close to landing. (About 30kft IIRC.)
I never said (or implied) it was practical (or even possible) given current technology... only that behaving as if the heating problem was axiomatically unavoidable is not, in fact, true.
If it requires science fiction technology to avoid (which it does) - then it is by definition unavoidable.
Actually, Scaled Composites does have experience in each and every one of the areas listed.
Let's take a look and see.
1) low cost reuseable engines: The Scaled hybrid engine is mostly reuseable, and was designed mostly in house by Scaled Composites.
Is it directly useable for an orbital craft? No. It it scaleable for an orbital craft? No.
Next.
2) low cost reusable ablators: The ablators on the leading edges of SS1's wings are a propritary Scaled design that is far cheaper, lighter, and more effective than any other system.
It is useable for an orbital system? No. Is it scaleable for an orbital system? No.
Next.
3) "Flight test experience is irrelevant". WTF?
Is the flight test program of an orbital craft anything like that of an aerodynamic craft? No.
In a conventional re-entry, most of what is being bled off is horizontal velocity. Vertical velocity is controlled by ballistic or aerodynamic lift. (Which is why Shuttle and Soyuz don't face the problems your vertical entry does.) However, when you are coming in vertically you cannot generate any ballistic or aerodynamic lift.
Okay... every freaking time this subject comes up (which you all know is fairly often) at least part of the thread gets hijacked into a detour on re-entry heating and "how in the heck is Rutan going to solve that problem", etc.
That's because it's a *huge* problem - everything else is fairly straightforward.
IANARS, but I do know a thing or two about aerospace principles and technology due to the education I *do* have. What I always find amusing about this particular area of the discussion (re-entry heating) is that everyone posting seems to take for granted that re-entry heating is an axiomatic phenomenon that MUST be faced head-on.
That because - it does in fact have to be faced head-on. There is no way around it. Period. (BTW, the issues in question are not aerospace principles - it's ballistics.)
The simple fact is that you can re-enter the atmosphere with little or no heating... all you have to do is SLOW DOWN!
In a nutshell - if I can slow my craft down enough (think "retro-rockets" here) then I can practically "float back down" into the atmosphere with minimal heating.
Except - you won't 'float down'. You are falling and *accelerating* at 32 ft/sec^2. By the time you hit entry interface your vertical velocity is actually greater than that of the Shuttle.
Conventional re-entries use angled trajectories so they do most of the slowing down fairly high up - where the atmosphere is thinner and the heat load lower. Your scheme does most of the (aerodynamic) braking in the worst possible place - moving fast, fairly low. Vertical drops can't brake up high because they are moving too slow for significant aerodynamic braking, and traverse the thin portions of the atmosphere too quickly. (Which sounds contradictory - but it's not.)
Rutan has several things working for him: he has a small, talented team. He has few or no political constraints. Theirs is a low-ceremony culture (NASA thinks in terms of paper reviews). SC are masters at materials and airframe design, and they are very good and experienced at flight test - both strategy and tactics.
He also has several things working *against* him. His team has no experience in designing or building high performance craft. (Nobody really does, not even NASA.) Nobody, anywhere, has any experience in building low cost reuseable engines. Nobody, anywhere, has any experience in low cost reusable ablators. These are two big problems - airframes and materials (his two great strengths) are virtually non problems. Flight test experience is irrelevant.
Hopefully the engineers at Scaled and Virgin know more than you (and the author of the linked page) do. Who's to say that a direct descendant of SS1 wil not (gasp!) change engine technologies?!
Who's to say? Pretty much anyone with a decent working knowledge of the field. There's no technology anywhere on the horizon to significantly drop the cost or weight of the engines an orbital craft will require.
This as got to be one of the most stupid posts/pages that I've seen so far this year.
The page discusses cold hard facts. What do you have to counter them other than handwaving hopes?
And assuming that they start on the ground. The lift they get by the "white knight" is a very big saver on fuel and engine weight since they do not have to go through the first layers of the atmosphere.
Actually - that's only true for fairly low performance vehicles (SS1/SS2). For orbital vehicles, the cost/size of carrier aircraft skyrockets, and the amount of weight saved on the carried vehicle plummets. An aircraft capable of carrying the orbital equivalent of SS1 will be very large and very expensive. (Think 747/C-5A/AN-225.)
Air launch *seems* obvious, but in reality it doesn't work so well.
This new plane is supposed to be able to carry 300 people at Mach 2. Concorde's top speed was Mach 2 as well. It was designed over 40 years ago.
I'd have thought we'd be capable of at least twice that by now.
Why would you think so? The laws of physics haven't changed in that time. A new wonderalloy hasn't appeared in that time either (despite a *huge* market for it).
Concorde didnt have a failed business model, it was actually making money on each flight once British Airways took over Concorde operations totally. What it did have was huge development costs, mainly because in the end only 14 aircraft were sold.
In other words - it only made money because the largest single cost (purchase) was paid for by the British Goverment. BA got the aircraft essentially for free.
Any accountant will tell you that betting on getting free investment capital is a business model gaurunteed to fail.
I still think wingless is the best way to go for the Kliper and/or the CEV. Unless you are taking off from a horizontal position, those wings are just dead weight.
False. The wings allow significant maneuverability during re-entry. Without that, you either need a *huge* target area (the steppes, the Pacific Ocean), or you have to wait until your landing target is directly in line with your orbital path. (For most orbits this means 1-2 times a day, seperated by 12 hours.)
When Discovery landed the other week, they had 5 different chances to land at two different sites within an eight hour time period - all because of the wings. Without wings, it would have been one shot at the Cape, another some hours later at Edwards, then eighteen odd hours before another shot at the Cape was available.
How about comparing length of service and overall cost in those figures?
Why? The question was reliability and safety.
If I remember right, a shuttle launch costs around $500 million and a Soyuz is about $50 million.
The marginal cost of a Shuttle flight (the cost to add one more flight to the schedule) is around 180 million, and for that you get a far greater passenger, cargo, and operational capacity than you get from Soyuz. One might as well compare apples and orangutans.
As long as you don't lose the crew, the important factor is total cost. I'd say that Soyuz delivers better value
Only if your sole metric is cost. In the real world, real engineers compare performance as well.
According to this page, total crew loss on Soyuz is 4 and the Shuttle is 14. That means that Soyuz has one loss in 20 flights whereas the Shuttle is more on the order of 1 loss in every 8.
Nope. They have both killed about 2% of the seats (not individuals, as many individuals have flown more than once) they have launched. (And Soyuz has done so in 87 flights, compared to 115 for Shuttle.)
I should also note that the last death in a Soyuz occurred in 1971.
So? In the real world real engineers look at performance records - and the record for Soyuz isn't pretty. It has an ongoing record of near misses.
The truss... isn't a beam.
Whether you call it a truss or a beam, at the end of the day it's used to hook other elements of the station together.
Only if you handwave away the functions of the equipment mounted on the Z1 truss.
Can you explain how only one truss would cost $600 million? Even if you load it up with a bunch of gear, I just don't get the cost.
Try reading the articles I linked.
On a related note: On good thing about the Shuttle/ISS sucking up most of the space dollars is that it's forced us to fly deep space missions on a budget. For example, the two Viking landers in the 70's cost several billion because we made them powered landing systems.
No. They were expensive because they were sophisticated and complex landers - the life detectors alone are more complex than anything landed since.
The airbag approach of the Mars landing systems has dramatically cut the expense, and we're getting really good science to go along with it.
No. We've switched to airbags because the probes are smaller. Period.
The great thing about flying less expensive, redundant systems is that if both survive the journey then you're ahead of where you would be with a single, more expensive system.
Not really. No matter how many duplicates of a simple, cheap system you fly, you won't have the same instruments that a larger more expensive system will have.
(as I can't recall a SINGLE EVENT where a capsule has burned up and people have died in reentry.)
The Russians have had two serious reentry failures. One flight had a decompression during re-entry, killing the crew. On another flight the orbital module failed to separate - and Soyuz is stable nose-first in that configuration. The capsule got hot enough to scorch the paint on the *inside* of the crew compartment before the orbital module tore away and the crew compartment flipped over into it's proper position.
I also doubt a single beam actually cost 600 million.
http://www.spacedaily.com/news/shuttle-02d.html
The truss, regardless of what Space Daily says, isn't a beam. It's a complex collection of support systems contained within the structural truss. (See the articles on the Z1 truss here and here.)
[In passing I note Space Daily is about as reliable as the wind.]
I'm not an aerospace engineer, but I am an engineer. I'm an engineer who believes in redundant systems and simple solutions over "space hardened" systems.
Experience however proves that your belief is incorrect.
There are lots of examples of guys building working systems on shoestring budgets that last well beyond their engineered lifetimes. Check out http://www.hypocrites.com/article2897.html for just one example.
For every 'cheap' spacecraft that last beyond it's modest goal, there's two more that don't meet theirs. (And the bird whose story you linked to hasn't in fact exceed it's engineered lifetime yet.)
I find it interesting that NASA always talks about how they fly the most complex systems in the world, yet somehow its the Russians with their 40 year old designs that have the most reliable systems.
Soyuz - 80 flights, 2 fatal accidents, 4 near fatal accidents, 4 complete loss of mission failures, and numerous serious incidents on landing. Shuttle - 115 flights, 2 fatal accidents, one loss of mission failure. (And that was a partial failure - the flight hardware was later reflown, something impossible on Soyuz.)
Did anyone notice that NASA spent $1 billion to fix the foam problem that caused the destruction of the Columbia shuttle? Yet, after spending $1 billion, the foam problem manifested itself again during the launch of Discovery.
False. The chunk of foam that had everyone concerned came from an area that has not been observed to shed foam since 1982. None of the areas that were fixed shed any foam.
The failure of Columbia was not a failure of engineering. Successful rocket launches occur often in Japan, Europe, and Florida.
False. Sucessful launches elsewhere have utterly no bearing on whether or not the Shuttle is an engineering failure.
The failure of Columbia was a failure of management. Managers wanting to show results to their superiors ignored the "grunt" engineers when they warned of a potential problem with tragic consequences for Columbia. The warnings became reality.
False. Despite the popular mythology of perfidious managment, there's not a shred of evidence that your fantasy resembles reality in any way, shape, or form. The overwheliming evidence that the *engineers* concluded that the foam was a maintenance (of the tiles) issue and that managment concurred in the assesment.
The shuttle may be "flawed" as you put it. Or maybe spaceflight is just dangerous? Do we really have reason to believe the next generation craft is going to be safer? If so, how much safer?
A lot of people tend to assume that space travel is inherently dangerous, but that isn't necessarily true. Just look at the Russian Soyuz, which hasn't had a fatality since 1971.
Yes, lets.
Since 1971 the Soyuz has had - 2 nearly fatal launch accidents, 4 loss-of-mission accidents on orbit, 2 nearly fatal reentry accidents, and multiple significant landing accidents. All of this in just under 70 flights.
In just the last two years they've had a complete loss of the flight control computer during re-entry, an undocking accident that resulted in recontact, and several pyros fired accidentally during launch preparation. (That's 3 major problems in just four flights.)
Not a very pretty record for a craft thats flown only eighty-odd times. They've avoided killing someone mostly by luck.
They have considerable real assets, a 20% profit margin, the strongest brand in their industry, and an employee roster that holds some of the best minds in the business, how exactly are they extremely inflated?
Because the stock price far exceeds any reasonable multiple of cash flow - and they don't pay dividends.
The power brokers have always been about "making a buck". But my dads generation did not lie awake at night thinking of being billionaires. The dream of a lot of people was being a hero, flying around the world like other great explorers or eventurers, hitting a home run, shooting for the stars.
The 1950's to 1970's saw a lot of people dreaming to be great scientists.
And for a lot of people - those dreams remain. But what people dream of and how people act are two very different things. As a culture America has been about making a buck and getting ahead since the colonial days. Period.
Slashdot Mirror
Some improvement.
Venice's problems aren't caused by global warming nor by geology. They stem from a decision in the 1800's to freeze the city in time as a tourist attraction.
If you go back to the Victorian Era, you'll find a rich and diversified British cuisine - but a century that includes massive industrialization, WWI, the Great Depression, WWII (and the austerity that followed) and a massive demographic shift from rural to urban has all but wiped it from living memory. Frankly, after studying food and cooking for nearly two decades - of all the world, the British are the most ignorant of their own food heritage. Even my fellow Americans as McBrainwashed as they are have a dim idea that there are regional cuisines and dishes.
To wit:
- "F3.8-2 The wing leading edge Reinfoced Carbon-Composite material and associate support hardware are remarkably tough and have impact capabilities that far exceed the minimal impact resistance specified in their original design requirements. Nevertheless, these tests demonstrate that this inherent toughness can be exceeded by impacts representative of those that occured during Columbia's ascent."
You also need to understand that a hole is not needed to destroy the Shuttle - a significant divot will do, as will a good sized crack.Certainly. It's also clear that the CAIB found no evidence that ageing effects played a role in the accident - had they felt it worth testing, it would have been tested. The bolded statement above directly indicates that they felt it not to be needed - as large impacts exceed the specifications of a new panel.They performed extensive analysis and testing of everything they felt might have played a role - and ageing effects are absent from that analysis and testing. Indirect evidence shows it to be a concern, but that they did not feel it played a role. In addition, had they felt it played a role, it would have been in the Findings, which it was not.Next.
It is useable for an orbital system? No. Is it scaleable for an orbital system? No.Next.
Is the flight test program of an orbital craft anything like that of an aerodynamic craft? No.Three strikes.
I forgot to add:
In a conventional re-entry, most of what is being bled off is horizontal velocity. Vertical velocity is controlled by ballistic or aerodynamic lift. (Which is why Shuttle and Soyuz don't face the problems your vertical entry does.) However, when you are coming in vertically you cannot generate any ballistic or aerodynamic lift.
Conventional re-entries use angled trajectories so they do most of the slowing down fairly high up - where the atmosphere is thinner and the heat load lower. Your scheme does most of the (aerodynamic) braking in the worst possible place - moving fast, fairly low. Vertical drops can't brake up high because they are moving too slow for significant aerodynamic braking, and traverse the thin portions of the atmosphere too quickly. (Which sounds contradictory - but it's not.)
Air launch *seems* obvious, but in reality it doesn't work so well.
Any accountant will tell you that betting on getting free investment capital is a business model gaurunteed to fail.
When Discovery landed the other week, they had 5 different chances to land at two different sites within an eight hour time period - all because of the wings. Without wings, it would have been one shot at the Cape, another some hours later at Edwards, then eighteen odd hours before another shot at the Cape was available.
[In passing I note Space Daily is about as reliable as the wind.]
Experience however proves that your belief is incorrect.For every 'cheap' spacecraft that last beyond it's modest goal, there's two more that don't meet theirs. (And the bird whose story you linked to hasn't in fact exceed it's engineered lifetime yet.)Soyuz - 80 flights, 2 fatal accidents, 4 near fatal accidents, 4 complete loss of mission failures, and numerous serious incidents on landing. Shuttle - 115 flights, 2 fatal accidents, one loss of mission failure. (And that was a partial failure - the flight hardware was later reflown, something impossible on Soyuz.)Who precisely is safer and more reliable?
Since 1971 the Soyuz has had - 2 nearly fatal launch accidents, 4 loss-of-mission accidents on orbit, 2 nearly fatal reentry accidents, and multiple significant landing accidents. All of this in just under 70 flights.
In just the last two years they've had a complete loss of the flight control computer during re-entry, an undocking accident that resulted in recontact, and several pyros fired accidentally during launch preparation. (That's 3 major problems in just four flights.)
Not a very pretty record for a craft thats flown only eighty-odd times. They've avoided killing someone mostly by luck.