Yes but do not forget making rocket fuel out of martian atmosphere with seed hydrogen stocks is an elemetary task already demonstrated.
But then you have to launch the hydrogen from the surface of the Earth and then send it to Mars. The whole point of the water on the moon is that it doesn't require that.
Higher gravity means less deterioration of calcium in bones during long duration stays.
It is simply unknown what effects either Martian or lunar gravity has on bones. There is no current way to work this out. It may be that lunar gravity is fine for bones; or even Martian is inadequate. We simply don't know.
Actually, conditions being what they are on the two bodies, and technology being what it is today, it's actually *easier* to get to the surface of Mars than the surface of the Moon (from LEO, it's 4.5 km/s Delta-V for Mars vs. 6.0 km/s for the Moon), and Mars is a safer place once you're there.
True, but misleading. The trip is about 9 months longer; and getting back again takes a much bigger delta-v from Mars than the Moon- in fact the round trip to Mars is a rather higher delta-v than the round trip to the Moon.
So if you are sending people, it's longer, further and more dangerous mission (solar flares and equipment reliability are issues).
And then when you get to Mars, you either turn around and come back within a few days, or you're stuck there for 18 months due to orbital dynamics (Mars has to be opposite the Earth from the Sub for the return trip and this happens every 18 months.) You can stay on the moon for as long or short as you want.
Sure, the Moon isn't as exciting, but nevertherless, it's much easier. And if the water is there in mineable quantities, the Moon is immediately useful- for, for example, enabling passage to Mars.
Evolution happens in leaps rather than continuously; isn't DNA supposed to be subject to larger, sudden changes as well?
Yes, and no.
Evolution is a combination of mutation and selection.
Mutation happens all the time, and is usually negative or irrelevant (most often irrelevant). It happens at a somewhat fixed rate. If negative, the mutation will not survive; irrelevant changes will often persist.
Just occasionally the mutation is wildly successful, and in that case can be wildly successful and will often spread through the population- so the change will often appear in a populaton suddenly (and of course there is an associated genetic change with this.)
Yeah, so it's well worth asking the question about why NASA built a Ferrari when they obviously need a Ford F-150.
I used to have an alpha of this on my system
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Omniscience Protocol
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· Score: 1
That version mostly only scrambled harddrives though. In the end I uninstalled it. I believe the early development name of the alpha version was 'Windows 95'.
In a real sense; the documentation is just introductory and/or a summary of the system from a few different angles.
Ultimately, it's just a map, and the map is not the territory.
I've written the documents, I've done week long teaching on the system; I've given a sort of apprenticeship to students (generally given them bugs to fix helps quite a lot.)
They all work to a degree.
Ultimately though; the code is the real deal; people just have to learn it; it takes months/years.
You still owe me the answer how you like to shift over such a subsystem to a new worker taking over your position when you move on to the next challange... he only has code and pseudo code.
I wouldn't know, I've never been in that position; I usually hand them an inch thick document as well as the code. It just doesn't contain any significant flow charts because they suck.
From what I can tell, the systems you work on are so heavily constrained that a flowchart actually makes sense.
The systems I have worked on in my career tend to be simultaneously huge, embedded, realtime, persistent, concurrent *and* multitasking- at the same time. And I am *not* just throwing buzzwords at you. I also had to work on projects with 500+ people working on the same product or several versions of the product. In situations like that I have not found flowcharts to be especially useful.
In fact, in that environment, I have found *detailed* documentation to be counterproductive. Sure I can draw the flowcharts and all the other diagrams- but reviewing and reading the multi-inch documents becomes a practical impossibility; even an inch is almost too big. So we have to get rid of the cruft. And flow charts are cruft.
If you have a large system or a complicated system, the high level design should be done with flowcharts/activity diagrams.
In my experience they are rarely useful. They manage to fall in the no mans land between accuracy and useful approximation; getting the worst of all worlds. Pseudocode is generally better.
How do you do that if you don't have every line of code in your mind?
Simple. I don't work on subsystems with more than 200,000 lines of code.
The records show that Soyuz is as safe as the Shuttle- about a 1.7% fatality rate per launched person. In fact, the latest manned version of the Soyuz has had NO fatalities whatsoever- they've had some injuries though. Even if you include the whole of the Soyuz program, then less astronauts have died per launched astronaut; but there's nothing much in it (it's not statistically significantly better than the Shuttle.)
Ironically though, Soyuz has had more missions that failed (the early Soyuz's were known to be a bit iffy so they launched less astronauts on them; they've hopefully got the bugs out now- and so they launch an extra person.) One mission had a launch pad fire that meant that the cosmonauts had to use an escape system- note that the Shuttle doesn't have an escape system.
So bizarrely, Soyuz is about as safe (or safer), but less reliable.
Actually, the Roton design (of the now sadly ex Rotary Rocket company), should have come in cheap enough that Gates could have easily afforded it. Still, that program was fairly high risk. I think they were predicting about $200 million to complete the program.
The Soyuz costs about $15-25 million to launch. Of course they charge a lot more than that- 60 million for the whole rocket IRC.
So the tourists are paying most of the unit costs of the rocket- and the Russians get to send along 2 more astronauts (cosmonauts) as well.
Yes, the Soyuz rocket really is that cost effective (the Russians use this amazingly hi-tech special technology called a 'production line' and the rocket is designed from the ground-up to be cheap/rugged- unlike in the West where it is designed to be 'high performance'.) It's a very different mindset.
I remember one of the American astronauts was asking one of the technicians wearing an ordinary white coat, standing next to the rocket he was about to launch on about whether the nozzles can swivel. "Oh yes up to 30 degrees! Watch"- *wrench* (bonk- hit's the stops), *wrench* (bonk- hit the other stops). Astronaut starts sweating. (Apparently in the west they tend to go with a clean-room attitude to their rockets and treat everything gently like it is made of glass- the Russians are more pragmatic about something about to see the brutality of a launch environment.)
Well, I kind of think of it as a 'goto considered harmful' sort of deal. There's probably situations where a flowchart is exactly the right diagrammatic tool to use for the task in hand; in which case you still shouldn't use it because everyone will laugh at you:-)
Actually, in situations like you are describing pseudocode is good.
I've seen a major revision of a large commercial computational program wither on the vine due to misunderstanding how to best apply object based thinking.
Lots of people don't seem to be able to hack it for some reason- with OO systems (and non OO too), knowing what makes a good object/structure is an art.
The nearest thing to flowcharts that are used in OO are:
state diagrams
message sequence charts
Neither are flowcharts, and if you try to use them as flowcharts (which I have seen done:-( ), bad things (tm) happen to your design. (States on state diagrams are states that parts of the system are supposed to be in for extended periods- message sequence charts are different because the flow is usually multitasking/parallel processing).
Personally, if I see somebody drawing a flowchart, I know they aren't currently up to scratch (which doesn't mean that they can't get better).
Actually, flowcharts are good for telling users what to do, and for similar reasons, might be appropriate for designing test scripts. But for the system- nope.
No; it's not about the quality of them, it's about what happens if you have a bunch of high quality choices- how long does it take you to decide which one to get?
You know, decisions decisions:
Shall I have Cindy Crawford, Beyonce Knowles or Sarah Michelle Gellar today?
Hmm. This could take a while.
OTOH. Choosing between Cindy Crawford and Cindy Crawford won't take long at all. All they are saying is that choosing time is heavily non linear on the number of options.
Location near the top of Earth's gravity well. We here on Earth are the "gravitationally disadvantaged". We are at the bottom of a pit 6,400 km (4,000 miles) deep. This is what makes space launches from the surface so difficult and expensive. Settlers near the top of the gravity well would be ideally situated for departures to points beyond.
That matches what I've always thought too. Planets are nice places to visit, but I wouldn't want to live on one.
For what? It won't burn. Mars doesn't have any free oxygen in its atmosphere.
Re:Doubt it Re:10 seconds
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X-43A Hits Mach 7
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· Score: 2, Informative
Um. No. Density of LH is a tiny fraction of gasoline- just 70kg/m^3.
Compare this to liquid oxygen which is (IRC) more like 1100 kg/m^3; or water 1000kg/m^3. Gasoline or kerosene is slightly lighter than water, but not a lot. Liquid Hydrogen is seriously not dense- that's actually the biggest problem with it.
When has he been to Mars?
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Methane on Mars?
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· Score: 4, Funny
The leader of the ground based astronomy team, Michael Mumma of the Goddard Space Flight Center, when asked if the methane was biological in origin, said 'I think it is, myself personally.'"
Well, atleast he's not denying it. How did Michael get to Mars? Gee, he must have a heck of an intestinal disorder for it to be detectable with a telescope!
Doubt it Re:10 seconds
on
X-43A Hits Mach 7
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· Score: 2, Interesting
I've a sneaking suspicion that it would only work for 10 seconds- 'strapping on a bigger tank' would probably result in it melting. They've probably used heatsink materials to soak up some of the awesome heating effects you get at mach 7.
Besides, where would they put the bigger tanks? The thing is tiny; and hydrogen is seriously not dense; meaning very little fits into the vehicle.
That said, the bureaucratic monstrosity known as "NASA" is a pale, bumbling and bloated organization with little resemblance to the group that ran the Apollo project.
There's only ever been one Von Braun.
The guy had the whole Apollo program in his head- he expertly guided the program through to completion. Then he retired- right after launching Skylab.
Basically it uses a precooled jet engine/rocket engine. They believe it would achieve 10:1 thrust:weight and roughly 2000-3000 seconds upto mach 5.
The difficult bit is the precooler, but they've done lab tests on one they built and it doesn't ice, and does work (although they mention unspecified 'manufacturing difficulties' which probably means you can't actually build one big enough or something).
I don't know- it looks promising. $10 billion though.
By the time you make the whole thing 'work', you end up spending a great deal of weight and complexity, and expense...
Yup. The point is that you gain performance by reducing propellent weight, and by making the system reusable. And yes, of course a reusable system is a priori more expensive. But the amortised cost, if you get the vehicle design right, will be lower.
Slashdot Mirror
But then you have to launch the hydrogen from the surface of the Earth and then send it to Mars. The whole point of the water on the moon is that it doesn't require that.
Higher gravity means less deterioration of calcium in bones during long duration stays.
It is simply unknown what effects either Martian or lunar gravity has on bones. There is no current way to work this out. It may be that lunar gravity is fine for bones; or even Martian is inadequate. We simply don't know.
True, but misleading. The trip is about 9 months longer; and getting back again takes a much bigger delta-v from Mars than the Moon- in fact the round trip to Mars is a rather higher delta-v than the round trip to the Moon.
So if you are sending people, it's longer, further and more dangerous mission (solar flares and equipment reliability are issues).
And then when you get to Mars, you either turn around and come back within a few days, or you're stuck there for 18 months due to orbital dynamics (Mars has to be opposite the Earth from the Sub for the return trip and this happens every 18 months.) You can stay on the moon for as long or short as you want.
Sure, the Moon isn't as exciting, but nevertherless, it's much easier. And if the water is there in mineable quantities, the Moon is immediately useful- for, for example, enabling passage to Mars.
I'm thinking. Oooh. Wingless angels. Can I have one of the females? "Research". Honest.
Thunderbirds are go! :-)
(Gonna require some souping it up a little though- how fast does this cut again? Nuclear power to the rescue! )
Yes, and no.
Evolution is a combination of mutation and selection.
Mutation happens all the time, and is usually negative or irrelevant (most often irrelevant). It happens at a somewhat fixed rate. If negative, the mutation will not survive; irrelevant changes will often persist.
Just occasionally the mutation is wildly successful, and in that case can be wildly successful and will often spread through the population- so the change will often appear in a populaton suddenly (and of course there is an associated genetic change with this.)
Yeah, so it's well worth asking the question about why NASA built a Ferrari when they obviously need a Ford F-150.
That version mostly only scrambled harddrives though. In the end I uninstalled it. I believe the early development name of the alpha version was 'Windows 95'.
Ultimately, it's just a map, and the map is not the territory.
I've written the documents, I've done week long teaching on the system; I've given a sort of apprenticeship to students (generally given them bugs to fix helps quite a lot.)
They all work to a degree.
Ultimately though; the code is the real deal; people just have to learn it; it takes months/years.
I wouldn't know, I've never been in that position; I usually hand them an inch thick document as well as the code. It just doesn't contain any significant flow charts because they suck.
From what I can tell, the systems you work on are so heavily constrained that a flowchart actually makes sense.
The systems I have worked on in my career tend to be simultaneously huge, embedded, realtime, persistent, concurrent *and* multitasking- at the same time. And I am *not* just throwing buzzwords at you. I also had to work on projects with 500+ people working on the same product or several versions of the product. In situations like that I have not found flowcharts to be especially useful.
In fact, in that environment, I have found *detailed* documentation to be counterproductive. Sure I can draw the flowcharts and all the other diagrams- but reviewing and reading the multi-inch documents becomes a practical impossibility; even an inch is almost too big. So we have to get rid of the cruft. And flow charts are cruft.
In my experience they are rarely useful. They manage to fall in the no mans land between accuracy and useful approximation; getting the worst of all worlds. Pseudocode is generally better.
How do you do that if you don't have every line of code in your mind?
Simple. I don't work on subsystems with more than 200,000 lines of code.
Ironically though, Soyuz has had more missions that failed (the early Soyuz's were known to be a bit iffy so they launched less astronauts on them; they've hopefully got the bugs out now- and so they launch an extra person.) One mission had a launch pad fire that meant that the cosmonauts had to use an escape system- note that the Shuttle doesn't have an escape system.
So bizarrely, Soyuz is about as safe (or safer), but less reliable.
Actually, the Roton design (of the now sadly ex Rotary Rocket company), should have come in cheap enough that Gates could have easily afforded it. Still, that program was fairly high risk. I think they were predicting about $200 million to complete the program.
So the tourists are paying most of the unit costs of the rocket- and the Russians get to send along 2 more astronauts (cosmonauts) as well.
Yes, the Soyuz rocket really is that cost effective (the Russians use this amazingly hi-tech special technology called a 'production line' and the rocket is designed from the ground-up to be cheap/rugged- unlike in the West where it is designed to be 'high performance'.) It's a very different mindset.
I remember one of the American astronauts was asking one of the technicians wearing an ordinary white coat, standing next to the rocket he was about to launch on about whether the nozzles can swivel. "Oh yes up to 30 degrees! Watch"- *wrench* (bonk- hit's the stops), *wrench* (bonk- hit the other stops). Astronaut starts sweating. (Apparently in the west they tend to go with a clean-room attitude to their rockets and treat everything gently like it is made of glass- the Russians are more pragmatic about something about to see the brutality of a launch environment.)
And of course, on the day it worked perfectly.
Actually, in situations like you are describing pseudocode is good.
I've seen a major revision of a large commercial computational program wither on the vine due to misunderstanding how to best apply object based thinking.
Lots of people don't seem to be able to hack it for some reason- with OO systems (and non OO too), knowing what makes a good object/structure is an art.
- state diagrams
- message sequence charts
Neither are flowcharts, and if you try to use them as flowcharts (which I have seen donePersonally, if I see somebody drawing a flowchart, I know they aren't currently up to scratch (which doesn't mean that they can't get better).
Actually, flowcharts are good for telling users what to do, and for similar reasons, might be appropriate for designing test scripts. But for the system- nope.
This stuff is radioactive. Do we really want to deorbit radioactive debris?
You know, decisions decisions:
Shall I have Cindy Crawford, Beyonce Knowles or Sarah Michelle Gellar today?
Hmm. This could take a while.
OTOH. Choosing between Cindy Crawford and Cindy Crawford won't take long at all. All they are saying is that choosing time is heavily non linear on the number of options.
That matches what I've always thought too. Planets are nice places to visit, but I wouldn't want to live on one.
For what? It won't burn. Mars doesn't have any free oxygen in its atmosphere.
Compare this to liquid oxygen which is (IRC) more like 1100 kg/m^3; or water 1000kg/m^3. Gasoline or kerosene is slightly lighter than water, but not a lot. Liquid Hydrogen is seriously not dense- that's actually the biggest problem with it.
Well, atleast he's not denying it. How did Michael get to Mars? Gee, he must have a heck of an intestinal disorder for it to be detectable with a telescope!
Besides, where would they put the bigger tanks? The thing is tiny; and hydrogen is seriously not dense; meaning very little fits into the vehicle.
There's only ever been one Von Braun.
The guy had the whole Apollo program in his head- he expertly guided the program through to completion. Then he retired- right after launching Skylab.
Once he went... NASA built the space shuttle.
Nuff said really.
Skylon may be an exception:
Basically it uses a precooled jet engine/rocket engine. They believe it would achieve 10:1 thrust:weight and roughly 2000-3000 seconds upto mach 5.
The difficult bit is the precooler, but they've done lab tests on one they built and it doesn't ice, and does work (although they mention unspecified 'manufacturing difficulties' which probably means you can't actually build one big enough or something).
I don't know- it looks promising. $10 billion though.
Yup. The point is that you gain performance by reducing propellent weight, and by making the system reusable. And yes, of course a reusable system is a priori more expensive. But the amortised cost, if you get the vehicle design right, will be lower.