NASA has probably been working on long-term life support because the ISS needs it.
ISS is resupplied several times a year, which won't be possible for a Mars ship. Also, I believe the benefits of nuclear propulsion would be used for reducing propellant mass, not speeding up the mission. And even if it did, you are still looking at a six-to-eight-year mission, at least.
The propulsion system has already been designed and tested and it is simpler in many ways than conventional rockets.
If you are thinking NERVA, there had indeed been some trials in the 1960s, but reviving the program would be much like restarting the Saturn V production chain, possibly harder than starting from scratch with non-obsolete tools. Perhaps it can be completed in a decade, but propulsion is not the only problem either (long-term life support, big lander, solar flare protection...)
Once you're in outer space, the only way to move is by conservation of momentum. That it to move forward, you have to throw something out the back (e.g. rocket engines). So to get to mars or anywhere else, you need to have enough fuel that can be thown out the back.
Correct, and we are still talking rocket engines. Except that instead of heating and expelling propellant thanks to a chemical reaction (hydrogen + oxygen -> water), you use a nuclear reaction (pump hydrogen--or just about any gas--into a nuclear reactor, heat it like hell).
The difference is that a nuclear rocket is much more efficient: the exhaust speed is much higher. Therefore the propellant mass required for a given change in speed is exponentially lower, due to the "rocket equation":
m/m0=exp(dv/u)
where m0 is your ship's dry mass, m its total mass (including propellant), dv the change in speed you aim for, and u the exhaust speed.
... as if anything had happened. NASA's reflex will probably be "great, we'll do it, triple our budget", and Congress' knee-jerk reaction will be "forget it". No?
Re:FTL == Time Travel ?
on
E ~ mc^2
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· Score: 3, Informative
Interesting material; I'm going to have to read it entirely (and find a way to keep the diagrams from displaying over the text... damn.)
The PostScript version might be more comfortable.
In your example, if X and Y share the same frame of reference, G and L may not be aware of anything, but the problem is that you don't take into account the point of view of someone traveling between X and Y, who will effectively see G going back in time, even if he takes the information travel time into account. (I shouldn't have mentioned seeing a "flash" in my previous message, it sent you off the wrong path...)
Did I miss something in your exemple? Could you describe the chain of events in more details?
The document will have told you all about it, but let's try. X is Earth, Y is Alpha Centauri, four light-years away and at rest relative to X. S is a ship traveling along the (XY) line at 0.866c, which yields a gamma-factor of 2. Times are measured in years, distances in light-years. t, t', t" are the times for X, Y and S.
Here are the events of interest in Earth's and Centauri's timeframe:
S passes X: t=t'=0, t"=0.
X sends a distress call to Y thanks to a "10c" device (so that it is not instantaneous): t=t'=4 (t"=2).
Y receives call: t=t'=4.4 (t"=2.2).
S passes Y: t=t'=4.6, t"=2.3; it is after Y got the message, so Y breaks the news.
Now, in the timeframe of S, things are slightly different; X and Y are seen as moving at 0.866c, and the distance between the two is only two light-years due to length contraction.
Two events are easy:
S passes X: t"=0, t=0 (t'=4.45).
S passes Y: t"=2.3, t=1.15 (t'=4.6 because they say so).
See? From the point of view of S, not only you cannot consider that the time is the same at X and Y, but if a message from X bears the date t=4 but has already arrived at Y at t=1.15, it looks like it has come from the future.
Now, to understand that it does not merely look like time-travel, suppose
Y tells S that X sent a distress call; S has the same kind of FTL device, which can reach X in
about 0.22 years (it is two light-years away in the timeframe of S, and receding at 0.866c). In the timeframe of S:
S sends inquiry to X: t"=2.3, t=1.15.
X receives inquiry: t"=2.52, t=1.26.
so X receives a message at t=1.26 which contains information about something about to happen at t=4, time enough to send Bruce Willis.
As you can see, there really is a paradox, which never appears without FTL devices.
Now, if you are not convinced, then I think you're thinking either:
S is moving but not X or Y, so the FTL device won't work the same, or:
when S passes Y and learns about X, it merely thinks that t=1.15, whereas it really is 4.6, or:
X does not move with respect to Y, whereas S is moving with respect to X, so the FTL communications won't work the same.
Item 3 could be valid, but you can always suppose that another ship S2 follows S and passes Earth at the right time; it won't be moving with respect to S, so FTL communications must work. For the other cases, you have to violate relativity in some way.
To settle it down, try to reverse the situation: A is Earth (time t), and two spaceships B and C (time t',t") are coming up on it at 0.866c, two light-years apart. In Earth's timeframe:
B passes A: t=t'=0.
C passes A: t=2.3, t'=1.15.
and in B's timeframe:
B passes A: t'=t"=t=0.
B sends out a distress call to C: t'=t"=4 (t=2).
C is four light-years away in this timeframe, the message will reach it at t'=t"=4.4 if it travels at 10c.
At t'=t"=4.6, C passes A (four light-years distance, still 0.866c) and tells them about B's problem.
When C passes A, in A's timeframe, t=2.3, t'=1.15; A sends a message to B at 10c, which arrives at t=2.52, t'=1.26...
If you object, remember, the situation has to be the same when you exchange A, B, C for S, X, Y, if no single frame of reference is to be privileged, so the objection has to work both ways.
If you single out a given frame of reference, however, and state that you believe that causality must only hold there, then you can build a consistent theory of FTL travel - the FAQ I pointed to does just that, by the way, when trying to reconcile Star Trek with relativity in part four. But I'm not too convinced by the postulated physics of subspace, and not sure that time-travel-like paradoxes are eliminated altogether.
Hm. That's assuming that what the law of causality describes as an 'observer' always uses his/her/its physical vision, which uses a speed-limited medium (light), and thus Causality's chain of events is defined by vision...
No. See my other reply, which is the one that should have been moderated up, not the one you are replying to.
I don't think that Causality cares much about who's there watching, when things happens. I always figured an 'observer' as something close enough, or able, to be in the same space _and_ time referential as the event, and above all _remain in the same referential_.
But you can't make that assumption; if a ship coming from Earth at high (but still sublight) speed crosses the Centauri system as you break the news, they will get the message although in their frame of reference the event really has not occurred yet. And if they also have FTL capability, they can send a message to Earth in time, effectively preventing an impact from happening thanks to the impact actually happening. Thus creating a time-travel-like paradox, which must be prevented, possibly by such means as you suggested.
About FTL itself, the whole point is making the travel's duration approach zero. An ideal FTL travel would make us go from one side of the universe to the other in no time flat, whatever size the universe is. No time travel involved. You wouldn't be 15+ billions years in the past, or future, or whatever, but exactly at the same time than anyone who didn't travel.
Anyone where? At what speed? In which gravity field?
Since, ideally, the events "departure" and "arrival" are in different places, they cannot be simultaneous in all frames of references; otherwise, you are implicitly supposing the existence of an "absolute" time, shared by everyone at every place in the Universe; this is exactly the hypothesis Relativity drops in favor of lightspeed being constant.
'Stretching it further' wouldn't change anything: the 'observer' (the FTL traveller) still doesn't stay in the same referential as the event during the whole incident (his time is 'compressed', while the event's is not).
Without knowing what kind of mechanism would produce FTL travel, one can't really argue about this, but the end result is the same. I really suggest looking at the FTL causality problem FAQ I pointed to in my other post.
If he actually managed to find an intact Earth _after_ it blew up, then A) it's the same Earth, when warning authorities hadn't worked, or B) it's a parallel earth, so the original event wouldn't have any impact (so to speak) to that universe's Causality.
Now that's another matter, and one which is, rightfully, just like time travel. And with such special provisions, then you can have FTL travel or communication, albeit restricted insofar as either some journeys or messages can be prevented in some circumstances (possibly including events which have not happened yet in your timeframe), or you may drop out into another Universe altogether. And then FTL travel isn't really fun, any more than time-travel in which you can't return to your particular time after killing your own grandfather...
I have been told that theory forbids any travel faster than light, no matter what the means ("warp drive", "hyperspace", "teleporter", whatever). My understanding is that if you could, some observers would see you traveling back in time, and this is forbidden.
Re:can someone explain to me
on
E ~ mc^2
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· Score: 2
Well, I ask the basic question: Why cant matter go faster than light?
People answer that the mass => Infinity as Speed => C
Why? There must be something holding it back from reaching C .
Not necessarily. First, I don't like that view of mass varying with speed, because then mass is no longer what one is used to. I prefer to reason in terms of momentum and kinetic energy: "p=(gamma)mv" and "Ec=(gamma-1)mc^2", with "gamma=1/sqrt(1-v^2/c^2)".
Then, as you can see, your momentum p climbs to infinity as you approach the speed of light. So, if you are to accelerate, a (finite) force F has to push you, and "dp/dt=F". But however strong F is, p cannot reach infinity in a finite time. Therefore you cannot reach lightspeed that way.
Re:FTL == Time Travel ?
on
E ~ mc^2
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· Score: 5, Interesting
I have been told that theory forbids any travel faster than light, no matter what the means ("warp drive", "hyperspace", "teleporter", whatever). My understanding is that if you could, some observers would see you traveling back in time, and this is forbidden.
Yes. One of the hypotheses of relativity is causality, that is, one event can possibly cause another only if the latter occurs at a later time than the former, and this must hold true for all possible observers whatever their frame of reference.
Now, as you know, the passing of time for an observer varies with his frame of reference (his speed, to put it simply). Hence, given two events, the interval of time from one to the other will not be the same for all observers. But if one is to cause another, it must always remain in its past; the sign of the time difference "t2-t1" must not change whatever the observer.
Unfortunately, my memories of relativity are too scarce to put this into equations, but if you could travel faster than light, you could, say, watch an asteroid smash into the Earth and warn your friend on the Centauri stock market to sell shares of all Terran businesses before anyone could "see" the flash of the impact.
And in a given frame of reference (maybe that of a traveler aboard a STL ship in-between), it would look as if you knew about it before it happened; stretching it further, it would be possible for the traveler (maybe through another FTL "jump") to warn Earth before the impact. Bye-bye causality.
If these situations are not to happen, information must not travel FTL.
Blame the Germans. France wanted to keep "ECU". (There being a French "écu" currency a few centuries back is purely incidental, of course...)
Re:And here's how they're going to do it
on
To the Moon and Beyond
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· Score: 3, Informative
According to this article, [bbc.co.uk] they're having problems getting a 'Beagle' robot up.
Your article dates from September. A more recent one reports that Beagle 2 is about to be delivered. OK, that doesn't mean the bugs have actually been ironed out, but at least it should launch.
Rosetta is due to launch in 2 weeks time, ready to rendevous and land on a comet in 2011. Assuming it doesn't blow up on launch.
It is supposed to be launched by a "classic" Ariane 5G which, rumor says, is not affected by whatever broke the last one (main stage nozzle cooling system, according to said rumor; this was supposed to increase the Vulcain's thrust by 20%).
But then, I'm the one who predicted this new Ariane 5 would send both the Atlas 5 and the Delta 4 back into the starting-block--and submitted the story right after its failure:-(.
As for this Aurora project, as long as the funding isn't there, I don't see how anything else than noise could come out, apart from a very cool logo--unfortunately I can't find a link: from left to right, da Vinci's "corkscrew" flying machine, a clipper sailboat, and some figurative solar sail spaceship; and the background fades also from left to right, from an old sailing map below a sky chart, to a satellite view of the Earth below the stars, the Moon and Mars.
Late == canceled?
on
Euro DMCA Fails
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· Score: 5, Interesting
It seems that only two member nations had adopted the local law and therfore the Euro wide law will not be adopted.
Don't rejoice too fast;
I fail to understand how the article implies that most member countries being late means that the directive will not be implemented...
Marc Andreessen proposes automating systems administration, arguing that humans are already at their limits, so scaling up the network require that the machines take care of themselves as much as possible. I fully agree. Basically, he just rediscovered what the Infrastructures.org people have been saying: that a network should be thought of as a single infrastructure, not a number of individual machines.
does anyone else have an opinion on the fact that the US is now THE power in space?
The Ariane 5 lifts more than any commercial US rocket; the very latest (Atlas 5, Delta 4) have just matched its performance, though hopefully the 10-ton version will up the bar again in two minutes; the Space Shuttle and Titan 4B have more capacity but cost two or three times as much.
Alcatel Space now builds over 50 percent of geostationary satellites.
The US manned space program, mostly the ISS, still depends on Russian Soyuzes (used as lifeboats) and will continue that way until 2010 at least.
Russia agreed to double Soyuz production starting in 2006. "The RSA's ISS partners will foot the bill".
This is required to support the ISS from 2006 (end of previous agreement) to 2010 (availability of new US spaceplane to act as lifeboat instead of Soyuz), preferably with more than 3 crew.
Hmmm, are we looking forward to another "we need more money or the crew has to leave" every week, like before the service module was launched?
Whatever the form of the eventual reusable launcher developed via the SLI, I'm pretty confident that it will be less expensive to opperate than the Shuttle fleet.
8<
The shuttles are very expensice. But, they were the first mostly-reusable spacecraft ever flown, and they taught us quite a bit about how to build their decendants.
Maybe. But this assumes that NASA is actually interested in reducing the costs, whereas a widely accepted theory is that they are more interested with playing with new technology, and keeping their current workforce and budget. Very commendable, but if the next vehicle requires further development instead of using off-the-shelf technology, and employs as many workers for its operations, how can it be cheaper?
NASA is a technology agency. That's its mission. It is not structured to design economical mass-transportation to orbit systems, and should not be trying to - for people are then convinced that their way is the only one, high costs for few people.
the other reason we don't use these for people is that it seems about every 1 in 10 of them blows up. The safety factors and redundancies aren't up to "human" standards.
It depends on the rocket, it can be as low as 1 in 30. Which doesn't prevent the Russians from sending people on expendable rockets, as they have a launch escape system (and it was actually used a couple of times), just like the Saturn 5 and its predecessors had, for Apollo.
In fact, I think the shuttle is the only manned launcher ever in which people were killed on take-off...
If we are to develop a space industry, then indeed these reliability rates are way too low.
They don't carry enough payload. They will carry up a 500-1000 pound satellite, but 2 people plus all the life-support crap necessary to keep them alive would weigh about the same.
The Delta 4 that was just launched has a payload capacity to low Earth orbit of over 11 metric tons (24,000 pounds). The heavy version will double this. Atlas 5 and Ariane 5 are at the same level or better.
The latest Soyuz-TMA (3 people, 14 days life support, 6 months orbital storage - little cargo, agreed) is a little over 7 tons.
I am not a rocket scientist, but I always thought the whole point of the shuttle was that it is resuable, thus saving money in the long run.
That's the idea on paper. However, this only works if the vehicle flies again and again; the current shuttle flight rate is about four to six a year (all four vehicles combined), and it requires a standing army of several thousand people to rebuild each one between missions - it is not a matter of "fueling her up, checking the oil, cleaning the windshield", more like swapping out the engines, replacing thermal tiles, and so on. And the airframes are aging, fast.
This puts the price tag for each flight in the $300 million range, or $10,000/kg (payload mass, not counting the hundred-ton shuttle deadweight).
With that kind of performance, the expendable launchers are more economical. Or you could say that the current shuttles are not, in fact, reusable.
Many space advocates believe that we now have the technology and know-how to cut those costs by a large factor, but that NASA and the big players have no interests in doing so. Check this previous/. story about "How the West wasn't won".
Isn't NASA working on a next generation shuttle for human missions?
They have just relaunched an orbital spaceplane program to alleviate the ISS' dependency on Russian Soyuzes; this would be a small (reusable?) vehicle housing up to ten people, launched either by a shuttle or a Delta 4 Heavy, to be used mainly as a lifeboat for the ISS so that more than three people can stay there for extended periods.
Other than that, the SLI program is more or less aimed at replacing the shuttle in a two or three-decade timeframe, and will probably produce yet another expensive all-in-one monster vehicle, if anything.
Hellooooooo! The eclipse causes more harmful rays to reach earth than normal?
Didn't you know the Moon was a giant magnifying glass in the UV wavelength? That's why those Apollo photographs are distorted, which causes some lunatics to think they were faked...
Slashdot Mirror
ISS is resupplied several times a year, which won't be possible for a Mars ship. Also, I believe the benefits of nuclear propulsion would be used for reducing propellant mass, not speeding up the mission. And even if it did, you are still looking at a six-to-eight-year mission, at least.
If you are thinking NERVA, there had indeed been some trials in the 1960s, but reviving the program would be much like restarting the Saturn V production chain, possibly harder than starting from scratch with non-obsolete tools. Perhaps it can be completed in a decade, but propulsion is not the only problem either (long-term life support, big lander, solar flare protection...)
Correct, and we are still talking rocket engines. Except that instead of heating and expelling propellant thanks to a chemical reaction (hydrogen + oxygen -> water), you use a nuclear reaction (pump hydrogen--or just about any gas--into a nuclear reactor, heat it like hell).
The difference is that a nuclear rocket is much more efficient: the exhaust speed is much higher. Therefore the propellant mass required for a given change in speed is exponentially lower, due to the "rocket equation":
m/m0=exp(dv/u)
where m0 is your ship's dry mass, m its total mass (including propellant), dv the change in speed you aim for, and u the exhaust speed.
... as if anything had happened. NASA's reflex will probably be "great, we'll do it, triple our budget", and Congress' knee-jerk reaction will be "forget it". No?
The PostScript version might be more comfortable.
In your example, if X and Y share the same frame of reference, G and L may not be aware of anything, but the problem is that you don't take into account the point of view of someone traveling between X and Y, who will effectively see G going back in time, even if he takes the information travel time into account. (I shouldn't have mentioned seeing a "flash" in my previous message, it sent you off the wrong path...)
The document will have told you all about it, but let's try. X is Earth, Y is Alpha Centauri, four light-years away and at rest relative to X. S is a ship traveling along the (XY) line at 0.866c, which yields a gamma-factor of 2. Times are measured in years, distances in light-years. t, t', t" are the times for X, Y and S.
Here are the events of interest in Earth's and Centauri's timeframe:
- S passes X: t=t'=0, t"=0.
- X sends a distress call to Y thanks to a "10c" device (so that it is not instantaneous): t=t'=4 (t"=2).
- Y receives call: t=t'=4.4 (t"=2.2).
- S passes Y: t=t'=4.6, t"=2.3; it is after Y got the message, so Y breaks the news.
Now, in the timeframe of S, things are slightly different; X and Y are seen as moving at 0.866c, and the distance between the two is only two light-years due to length contraction. Two events are easy:- S passes X: t"=0, t=0 (t'=4.45).
- S passes Y: t"=2.3, t=1.15 (t'=4.6 because they say so).
See? From the point of view of S, not only you cannot consider that the time is the same at X and Y, but if a message from X bears the date t=4 but has already arrived at Y at t=1.15, it looks like it has come from the future.Now, to understand that it does not merely look like time-travel, suppose Y tells S that X sent a distress call; S has the same kind of FTL device, which can reach X in about 0.22 years (it is two light-years away in the timeframe of S, and receding at 0.866c). In the timeframe of S:
- S sends inquiry to X: t"=2.3, t=1.15.
- X receives inquiry: t"=2.52, t=1.26.
so X receives a message at t=1.26 which contains information about something about to happen at t=4, time enough to send Bruce Willis. As you can see, there really is a paradox, which never appears without FTL devices.Now, if you are not convinced, then I think you're thinking either:
- S is moving but not X or Y, so the FTL device won't work the same, or:
- when S passes Y and learns about X, it merely thinks that t=1.15, whereas it really is 4.6, or:
- X does not move with respect to Y, whereas S is moving with respect to X, so the FTL communications won't work the same.
Item 3 could be valid, but you can always suppose that another ship S2 follows S and passes Earth at the right time; it won't be moving with respect to S, so FTL communications must work. For the other cases, you have to violate relativity in some way.To settle it down, try to reverse the situation: A is Earth (time t), and two spaceships B and C (time t',t") are coming up on it at 0.866c, two light-years apart. In Earth's timeframe:
- B passes A: t=t'=0.
- C passes A: t=2.3, t'=1.15.
and in B's timeframe:- B passes A: t'=t"=t=0.
- B sends out a distress call to C: t'=t"=4 (t=2).
- C is four light-years away in this timeframe, the message will reach it at t'=t"=4.4 if it travels at 10c.
- At t'=t"=4.6, C passes A (four light-years distance, still 0.866c) and tells them about B's problem.
When C passes A, in A's timeframe, t=2.3, t'=1.15; A sends a message to B at 10c, which arrives at t=2.52, t'=1.26...If you object, remember, the situation has to be the same when you exchange A, B, C for S, X, Y, if no single frame of reference is to be privileged, so the objection has to work both ways.
If you single out a given frame of reference, however, and state that you believe that causality must only hold there, then you can build a consistent theory of FTL travel - the FAQ I pointed to does just that, by the way, when trying to reconcile Star Trek with relativity in part four. But I'm not too convinced by the postulated physics of subspace, and not sure that time-travel-like paradoxes are eliminated altogether.
No. See my other reply, which is the one that should have been moderated up, not the one you are replying to.
But you can't make that assumption; if a ship coming from Earth at high (but still sublight) speed crosses the Centauri system as you break the news, they will get the message although in their frame of reference the event really has not occurred yet. And if they also have FTL capability, they can send a message to Earth in time, effectively preventing an impact from happening thanks to the impact actually happening. Thus creating a time-travel-like paradox, which must be prevented, possibly by such means as you suggested.
Anyone where? At what speed? In which gravity field?
Since, ideally, the events "departure" and "arrival" are in different places, they cannot be simultaneous in all frames of references; otherwise, you are implicitly supposing the existence of an "absolute" time, shared by everyone at every place in the Universe; this is exactly the hypothesis Relativity drops in favor of lightspeed being constant.
Without knowing what kind of mechanism would produce FTL travel, one can't really argue about this, but the end result is the same. I really suggest looking at the FTL causality problem FAQ I pointed to in my other post.
Now that's another matter, and one which is, rightfully, just like time travel. And with such special provisions, then you can have FTL travel or communication, albeit restricted insofar as either some journeys or messages can be prevented in some circumstances (possibly including events which have not happened yet in your timeframe), or you may drop out into another Universe altogether. And then FTL travel isn't really fun, any more than time-travel in which you can't return to your particular time after killing your own grandfather...
Much better than my previous comment, see this relativity and FTL travel FAQ, which has a chapter about just that question.
Not necessarily. First, I don't like that view of mass varying with speed, because then mass is no longer what one is used to. I prefer to reason in terms of momentum and kinetic energy: "p=(gamma)mv" and "Ec=(gamma-1)mc^2", with "gamma=1/sqrt(1-v^2/c^2)".
Then, as you can see, your momentum p climbs to infinity as you approach the speed of light. So, if you are to accelerate, a (finite) force F has to push you, and "dp/dt=F". But however strong F is, p cannot reach infinity in a finite time. Therefore you cannot reach lightspeed that way.
Yes. One of the hypotheses of relativity is causality, that is, one event can possibly cause another only if the latter occurs at a later time than the former, and this must hold true for all possible observers whatever their frame of reference.
Now, as you know, the passing of time for an observer varies with his frame of reference (his speed, to put it simply). Hence, given two events, the interval of time from one to the other will not be the same for all observers. But if one is to cause another, it must always remain in its past; the sign of the time difference "t2-t1" must not change whatever the observer.
Unfortunately, my memories of relativity are too scarce to put this into equations, but if you could travel faster than light, you could, say, watch an asteroid smash into the Earth and warn your friend on the Centauri stock market to sell shares of all Terran businesses before anyone could "see" the flash of the impact.
And in a given frame of reference (maybe that of a traveler aboard a STL ship in-between), it would look as if you knew about it before it happened; stretching it further, it would be possible for the traveler (maybe through another FTL "jump") to warn Earth before the impact. Bye-bye causality.
If these situations are not to happen, information must not travel FTL.
I wouldn't be so bold... I assume you didn't follow the "blow up" link in the story?
Blame the Germans. France wanted to keep "ECU". (There being a French "écu" currency a few centuries back is purely incidental, of course...)
Your article dates from September. A more recent one reports that Beagle 2 is about to be delivered. OK, that doesn't mean the bugs have actually been ironed out, but at least it should launch.
It is supposed to be launched by a "classic" Ariane 5G which, rumor says, is not affected by whatever broke the last one (main stage nozzle cooling system, according to said rumor; this was supposed to increase the Vulcain's thrust by 20%).
But then, I'm the one who predicted this new Ariane 5 would send both the Atlas 5 and the Delta 4 back into the starting-block--and submitted the story right after its failure :-(.
As for this Aurora project, as long as the funding isn't there, I don't see how anything else than noise could come out, apart from a very cool logo--unfortunately I can't find a link: from left to right, da Vinci's "corkscrew" flying machine, a clipper sailboat, and some figurative solar sail spaceship; and the background fades also from left to right, from an old sailing map below a sky chart, to a satellite view of the Earth below the stars, the Moon and Mars.
Don't rejoice too fast; I fail to understand how the article implies that most member countries being late means that the directive will not be implemented...
I recommend the paper, "Bootstrapping an infrastructure."
Aw, sh*t, good liftoff but first stage failure some time after booster separation. Boeing and LockMart just won a few months. It's not over yet.
The Ariane 5 lifts more than any commercial US rocket; the very latest (Atlas 5, Delta 4) have just matched its performance, though hopefully the 10-ton version will up the bar again in two minutes; the Space Shuttle and Titan 4B have more capacity but cost two or three times as much.
Alcatel Space now builds over 50 percent of geostationary satellites.
The US manned space program, mostly the ISS, still depends on Russian Soyuzes (used as lifeboats) and will continue that way until 2010 at least.
Want more?
Hmmm, are we looking forward to another "we need more money or the crew has to leave" every week, like before the service module was launched?
Maybe. But this assumes that NASA is actually interested in reducing the costs, whereas a widely accepted theory is that they are more interested with playing with new technology, and keeping their current workforce and budget. Very commendable, but if the next vehicle requires further development instead of using off-the-shelf technology, and employs as many workers for its operations, how can it be cheaper?
NASA is a technology agency. That's its mission. It is not structured to design economical mass-transportation to orbit systems, and should not be trying to - for people are then convinced that their way is the only one, high costs for few people.
It depends on the rocket, it can be as low as 1 in 30. Which doesn't prevent the Russians from sending people on expendable rockets, as they have a launch escape system (and it was actually used a couple of times), just like the Saturn 5 and its predecessors had, for Apollo. In fact, I think the shuttle is the only manned launcher ever in which people were killed on take-off...
If we are to develop a space industry, then indeed these reliability rates are way too low.
The Delta 4 that was just launched has a payload capacity to low Earth orbit of over 11 metric tons (24,000 pounds). The heavy version will double this. Atlas 5 and Ariane 5 are at the same level or better.
The latest Soyuz-TMA (3 people, 14 days life support, 6 months orbital storage - little cargo, agreed) is a little over 7 tons.
Conclude.
That's the idea on paper. However, this only works if the vehicle flies again and again; the current shuttle flight rate is about four to six a year (all four vehicles combined), and it requires a standing army of several thousand people to rebuild each one between missions - it is not a matter of "fueling her up, checking the oil, cleaning the windshield", more like swapping out the engines, replacing thermal tiles, and so on. And the airframes are aging, fast.
This puts the price tag for each flight in the $300 million range, or $10,000/kg (payload mass, not counting the hundred-ton shuttle deadweight). With that kind of performance, the expendable launchers are more economical. Or you could say that the current shuttles are not, in fact, reusable.
Many space advocates believe that we now have the technology and know-how to cut those costs by a large factor, but that NASA and the big players have no interests in doing so. Check this previous /. story about "How the West wasn't won".
They have just relaunched an orbital spaceplane program to alleviate the ISS' dependency on Russian Soyuzes; this would be a small (reusable?) vehicle housing up to ten people, launched either by a shuttle or a Delta 4 Heavy, to be used mainly as a lifeboat for the ISS so that more than three people can stay there for extended periods.
Other than that, the SLI program is more or less aimed at replacing the shuttle in a two or three-decade timeframe, and will probably produce yet another expensive all-in-one monster vehicle, if anything.
Actually no, the 1999 solar eclipse was visible from the Mir space station as a huge shadow on Earth. Spectacular.
Didn't you know the Moon was a giant magnifying glass in the UV wavelength? That's why those Apollo photographs are distorted, which causes some lunatics to think they were faked...
Hot.