Spirit was about to find evidence of an ancient ocean on Mars, but this would prove too costly for a certain chain of low-end sea food restaurants which recently announced an unusual publicity stunt.
So Spirit had to die . ..
Stefan
http://www.longjohnsilvers.com/press/nasa.htm
Comfort Food Re:What happened to standalone books?
on
The Golden Transcendence
·
· Score: 4, Insightful
People read books for different reasons.
Sprawling SF or F series fill a need that many people feel. They want a comfortable place to escape to. Fictional comfort food.
These are steady sellers, and some publishers favor them. Dedicated readers will keep buying them, out of a sense of loyalty or completeness, and forgive the occasional "dud."
OTOH, a fairly fast trip to Mars requires about 20 kps in velocity changes. Which makes a 30 kps ion drive just about right.
But there's complexities there, too. Most of these velocity changes come at the beginning and end of the journey (getting into an elliptical orbit, then getting out of it once you reach Mars).
Preemptive strike on Tau Ceti IV NOW!
on
The Future of NASA
·
· Score: 1
I think it's obvious that the most serious future threat to the country are alien civilizations.
If the president cares a whit about our safety, he'll authorize the construction of a giant deep-space multi-element telescope that will allow us to spot habitable worlds at distances of up to fifty light years.
And just in case the aliens have cloaking devices, we'll need telescopes capable of scanning the infrared and X-Ray parts of the spectrum. We may even need deep space gravity wave detectors, just in case. Whatever it takes to detect a threat.
Of course, danger need not come solely from Earthlike worlds. Every star systems within reach must be thoroughly surveyed for possible threats. for this reason, the president must fund research into fusion drives that would make interstellar probes viable.
If this means thousands of scientists will spend the rest of thier lives combing through vast reams of data, writing research papers, and dancing like giddy school girls over non-military discoveries they make in the mean time . . . so be it!
Weepy celebrities and televangelists could hold telethons to raise money to send supplies out there.
Each package would take years to arrive, traveling to Mars by slow, efficient orbits that criss-cross the inner system to build velocity before finally careening into Mars' upper atmosphere, reentering, and bouncing to a stop, persued by eager colonists in grubby, patched space suits.
"Dig deep my friends! Just $350 can send a package of Ramen Noodles to a needy Mars pioneer. A mere $500 can send this roll of single-ply toilet paper, or two day's worth of tampons, to a brave colonist. And imagine the joy this package of Jolly Roger treats could bring, for only $150."
. . . my inclusion of '(big "?")', and suggesting a trial first.
I lived in the Bay Area for several years, and know about the alien species problems.
If this scheme works, you'd want the temporary cover to grow like mad. It would be there to prevent runaway erosion and mud slides, which are both dangerous to people and destructive of the ecosystem.
It's a suggestion that might be worth trying, and an example of how something that many consider awful and ungodly might be put to constructive use.
Note that the last people I'd want to be involved in the trial would be Monsanto. Those arrogant clowns are responsible for much of the mistrust of GMO crops.
If you follow the link, you'll find that Monsanto, for whom I have no great love either, has abandoned the project.
A friend thought of a genuinely interesting use for a crop with terminator genes:
Erosion control.
There are several species of fast-growing plant what would be very useful for preventing (say) an hilly area whose forest cover burned away from eroding, but who are also dangerous "alien" species.
Kudzu is one example; more subtle is the bizarre-looking "ice plant" that was imported to California for erosion control along railways but has become a pest.
It might be worth a research project to look into whether a fast-growing erosion control plant equipped with terminator genes could stabilize a burned-out area, retaining the soil for long enough for native plants to get a toe-hold. And then die out . ..
. . . of owning a GMO Border collie with prehensile paws and a obsessive compulsive disorder that compels him to pair up my freshly laundered socks and keep my bookshelves in order.
If he can herd those damn neighbor kids off the lawn between laundry loads, so much the better. If he has any spare time after that, he's free to play cards with the neo-ferret who inspects the cable runs and cleans out the air ducts.
Nyahhhh, rotten kids and their goddamn glowing green racing llamas.
If you follow that link and see the forbidden image of a Zero-Point Energy module left behind when the Grays dumped Elvis' worn-out second body on Mars back in 1972, you're just asking to disappear one of these days.
In the short run: Footage of that first step onto the Martian surface for the current president to use in a campaign commercial.
In the medium run: Footage of that first step onto the Martian surface for crazed conspiracy theorists to pour over, looking for proof it was filmed in the Gobi Desert.
In the long run: Footage of that first step onto the Martian surface for MTV to repurpose.
(This is a funny post, but I could write a serious one too, but I'm also sure someone else will. Whether the someone else will avoid the usual brave pioneer spirit flag-waving manifest destiny let's leave this rock bullshit and point out the practical advantages you have to balance against the tremendous cost, I'm not so sure.)
He's counting on our aerospace industry locating overseas, where engineers work for $15 a day, thus cutting development and construction costs to the bone!
The Mars ship may not be made in America, and the crew will be Dynagen contractors, but we can take pride in the fact that exclusive broadcast rights of the landings will belong to American big media companies.
It makes me just want to rush out and buy the Revell model and imagine myself going back and forth between Earth and LEO in it, which is all that it will be doing.
On the other hand, maybe the name isn't clunky, but descriptive. The crew will be exploring themselves in it. That's it . . . NASA is getting into the space sex tourism business!
* * *
But seriously:
There's speculation that this will be a cone shaped "capsule," perhaps a bit bigger than the old Apollo capsule. I wonder what they'll use as a booster. A Titan with strap on boosters? A Delta? Some of the later variants of these rockets can carry a lot of payload, approaching the capabilities of the Saturn Ib.
They would have to be "man rated" first. I'm not sure what is involved with that . ..
I suppose it's possible that the CEV could be used for trips to Lunar orbit. This would probably require docking with a transfer stage. I think it would be interesting if this were a permenant resource, rather than something tossed after one round trip. It could concievably be the first nuclear-powered craft.
. . . or you're just asking to be turned into a walking, talking spam bot:
"Carbon units, take heed: Lengthen your reproductive extension! Wealthen yourself through expediting currency transfer for expired-dictator spouse-counterpart! Observe vixen-type hu-mans frolicking in their dorm-units!"*
Specific impulse is a clunky way of stating exhaust velocity.
It has nothing to do with a thrust to weight ratio.
In fact, ion motors, and proposed fusion motors (google for "inertial confinement fusion" and "magnetic confinement fusion") have a very high Isp (3000 seconds for ion motors, up in the mid 100,000 seconds for fusion motors) but generate very low thrust.
The stream of particles these motors produce move very quickly, but there aren't a lot of them.
Why is a high specific impulse a Good Thing?
Recall Newton's Third Law of Motion: Every reaction produces an equal an opposite reaction. Simply put: In a rocket, the momentum of the stuff the motor accellerates out the back ("reaction mass") translates into forward momentum. The faster the stuff you toss out the back, the more bang the buck you get out of that mass.
A higher exhaust velocity means you need less reaction mass, in terms of the percentage of your starting total mass, to achieve the same changes in velocity.
Here's the rocket equation:
M(f)+M(0)
--------- = e ^ (Vd/Vex)
M(0)
M(f) = mass of fuel
M(0) = mass of space ship w/o fuel
e = natural log number, about 2.718 is fine for these purposes
Vd = desired velocity change
Vex = exhaust velocity
The "velocity change budget" for a fast trip to Mars is about 20 kps. The exhaust velocity of a good chemical motor is about 5 kps. If you plug these numbers into the above, you find you need a mass ratio of 54:1 for your Mars trip. That is, 53 tons of fuel for every ton delivered to Mars orbit. With a nuclear fission rocket motor with a exhaust velocity of 10 kps, the mass ratio is more like 7:1.
The specific impulse (measured in seconds) remains the same no matter how many boosters there are.
You could gang together several motors to increase the delivered thrust, but the exhaust velocity would remain the same.
I couldn't find a figure for Isp on the research site linked to. The second article suggests an Isp of 3,000 seconds for his "lightbulb" motor, but that sounds awfully high for a fission rocket.
At the stage where this book breaks off the saga of Lucy, she is a one-eyed, legless agglomeration of springs and servos perched on a desk full of computers.
You are repeating FUD churned out by outfits like the American Enterprise Institute, Greening Earth Society, and other well-paid advocacy outfits.
Every one of these factoids has been disproved.
The vast majority of scientists agree that global warming is real, and that human activity is a major factor.
Through sheer volume and persistance the patsies of the fossil fuel lobby get their distortions onto editorial pages. They've fooled politicians, and lots of the public, but they can't fool Maw Nature, who can be a real bitch.
"Every time NASA sends a probe to Mars all we the public see are rocks and red dirt."
Because mostly that's all there is. Later probes might be able to roll or fly to interesting, spectacular places, but for now they are playing things safe.
". . . we're still sending probes!"
Well, yeah. Probes are cheap and have a high Find Things Out For The Buck ratio. There is a lot about Mars we simply don't know, including important things like how much water there is and in what form it is.
We have to know about these things before we can plan manned missions. Hyper-enthusiasts will tell you we can go to Mars tomorrow and create self-sustaining habitats the day after, but they are way full of it, cutting every corner and making every most optimistic assumption. (They're a lot like the L-5 enthusiasts of the 1970s. Anyone else remember them?)
Before you walk, you gotta learn to crawl.
Earthlike atmosphere? No, because Mars is very short on volatiles. Yes, there may well be enough water for a few small seas, and enough CO2 to create a thin atmosphere. But there's little or no nitrogen, and you'll have to crack the CO2 to create oxygen. And, I suppose, Ozone to screen out the U.V. And maybe how to create a magnetosphere from scratch to divert the solar wind.
Terraforming Mars would take centuries and probably involve importing gasses from moons and comets Out Yonder, and successive generations of tailored life forms to do the dirty work.
Slashdot Mirror
Spirit was about to find evidence of an ancient ocean on Mars, but this would prove too costly for a certain chain of low-end sea food restaurants which recently announced an unusual publicity stunt.
So Spirit had to die . . .
Stefan http://www.longjohnsilvers.com/press/nasa.htm
People read books for different reasons.
Sprawling SF or F series fill a need that many people feel. They want a comfortable place to escape to. Fictional comfort food.
These are steady sellers, and some publishers favor them. Dedicated readers will keep buying them, out of a sense of loyalty or completeness, and forgive the occasional "dud."
Different strokes for different folks.
Mars Crossing Over
with John Edwards
"I see . . . red rocks! Lots and lots of red rocks! Does that sound familiar?"
"Why, why yes!"
"Now, did this Spirit have . . . are they wheels?"
"Oh, oh yes, yes, Spirit does have wheels! Please, ask it if it's OK!"
"It says it's on a flat, red plain covered with red rocks, and that it's found life and water and everything there is peaceful and cool."
"Oh, thank you, thank you Mr. Edwards!"
Stefan
Don't forget the vast deposits of marzipan on Io.
On second thought, forget it. No one likes that stuff.
Of course, one of Saturn's moons is a giant Black and White cookie, so that might make up for it.
"You're making this up, aren't you?"
Yes. I was going to put in more clues, but didn't want to make it TOO obvious . . . #B^)
. . . of "Adirondack Al," the wise-cracking otter from the Allegheny Animation Studio's show _The Runciple Potts Hour_?
You know, ran on the Muntz TV Network?
Had the guy who played Commodore Langly on _Space: Mission Upwards_ as Runciple Potts, the friendly lumber deliveryman who introduced the cartoons?
Jeeze, kids these days don't have appreciation of culture.
Stefan
OTOH, a fairly fast trip to Mars requires about 20 kps in velocity changes. Which makes a 30 kps ion drive just about right.
But there's complexities there, too. Most of these velocity changes come at the beginning and end of the journey (getting into an elliptical orbit, then getting out of it once you reach Mars).
If the president cares a whit about our safety, he'll authorize the construction of a giant deep-space multi-element telescope that will allow us to spot habitable worlds at distances of up to fifty light years.
And just in case the aliens have cloaking devices, we'll need telescopes capable of scanning the infrared and X-Ray parts of the spectrum. We may even need deep space gravity wave detectors, just in case. Whatever it takes to detect a threat.
Of course, danger need not come solely from Earthlike worlds. Every star systems within reach must be thoroughly surveyed for possible threats. for this reason, the president must fund research into fusion drives that would make interstellar probes viable.
If this means thousands of scientists will spend the rest of thier lives combing through vast reams of data, writing research papers, and dancing like giddy school girls over non-military discoveries they make in the mean time . . . so be it!
Stefan
Estes still makes and sells a Saturn V kit, but a small outfit in CO sells a bigger version, with instructions in MPEG video form on CD-ROM:
http://www.apogeerockets.com/Saturn5.asp
They wouldn't be abandoned.
Weepy celebrities and televangelists could hold telethons to raise money to send supplies out there.
Each package would take years to arrive, traveling to Mars by slow, efficient orbits that criss-cross the inner system to build velocity before finally careening into Mars' upper atmosphere, reentering, and bouncing to a stop, persued by eager colonists in grubby, patched space suits.
"Dig deep my friends! Just $350 can send a package of Ramen Noodles to a needy Mars pioneer. A mere $500 can send this roll of single-ply toilet paper, or two day's worth of tampons, to a brave colonist. And imagine the joy this package of Jolly Roger treats could bring, for only $150."
Stefan "I'll stick with suborbital stuff!" Jones
That's the kind of feed back I like to see . . . from someone who works in the field.
What DO forestry folks due, if anything, after a big fire? Any plantings, etc.?
I lived in the Bay Area for several years, and know about the alien species problems.
If this scheme works, you'd want the temporary cover to grow like mad. It would be there to prevent runaway erosion and mud slides, which are both dangerous to people and destructive of the ecosystem.
It's a suggestion that might be worth trying, and an example of how something that many consider awful and ungodly might be put to constructive use.
Note that the last people I'd want to be involved in the trial would be Monsanto. Those arrogant clowns are responsible for much of the mistrust of GMO crops.
If you follow the link, you'll find that Monsanto, for whom I have no great love either, has abandoned the project.
.
A friend thought of a genuinely interesting use for a crop with terminator genes:
Erosion control.
There are several species of fast-growing plant what would be very useful for preventing (say) an hilly area whose forest cover burned away from eroding, but who are also dangerous "alien" species.
Kudzu is one example; more subtle is the bizarre-looking "ice plant" that was imported to California for erosion control along railways but has become a pest.
It might be worth a research project to look into whether a fast-growing erosion control plant equipped with terminator genes could stabilize a burned-out area, retaining the soil for long enough for native plants to get a toe-hold. And then die out . .
Stefan
If he can herd those damn neighbor kids off the lawn between laundry loads, so much the better. If he has any spare time after that, he's free to play cards with the neo-ferret who inspects the cable runs and cleans out the air ducts.
Nyahhhh, rotten kids and their goddamn glowing green racing llamas.
Stefan
If you follow that link and see the forbidden image of a Zero-Point Energy module left behind when the Grays dumped Elvis' worn-out second body on Mars back in 1972, you're just asking to disappear one of these days.
In the short run: Footage of that first step onto the Martian surface for the current president to use in a campaign commercial.
In the medium run: Footage of that first step onto the Martian surface for crazed conspiracy theorists to pour over, looking for proof it was filmed in the Gobi Desert.
In the long run: Footage of that first step onto the Martian surface for MTV to repurpose.
(This is a funny post, but I could write a serious one too, but I'm also sure someone else will. Whether the someone else will avoid the usual brave pioneer spirit flag-waving manifest destiny let's leave this rock bullshit and point out the practical advantages you have to balance against the tremendous cost, I'm not so sure.)
Stefan
The Mars ship may not be made in America, and the crew will be Dynagen contractors, but we can take pride in the fact that exclusive broadcast rights of the landings will belong to American big media companies.
It makes me just want to rush out and buy the Revell model and imagine myself going back and forth between Earth and LEO in it, which is all that it will be doing.
On the other hand, maybe the name isn't clunky, but descriptive. The crew will be exploring themselves in it. That's it . . . NASA is getting into the space sex tourism business!
* * *
But seriously:
There's speculation that this will be a cone shaped "capsule," perhaps a bit bigger than the old Apollo capsule. I wonder what they'll use as a booster. A Titan with strap on boosters? A Delta? Some of the later variants of these rockets can carry a lot of payload, approaching the capabilities of the Saturn Ib.
They would have to be "man rated" first. I'm not sure what is involved with that . . .
I suppose it's possible that the CEV could be used for trips to Lunar orbit. This would probably require docking with a transfer stage. I think it would be interesting if this were a permenant resource, rather than something tossed after one round trip. It could concievably be the first nuclear-powered craft.
Stefan "Likes to think he's a rocket scientist" Jones
"Carbon units, take heed: Lengthen your reproductive extension! Wealthen yourself through expediting currency transfer for expired-dictator spouse-counterpart! Observe vixen-type hu-mans frolicking in their dorm-units!"*
Stefan
* Stilted borg language added for comedic effect.
Specific impulse is a clunky way of stating exhaust velocity.
It has nothing to do with a thrust to weight ratio.
In fact, ion motors, and proposed fusion motors (google for "inertial confinement fusion" and "magnetic confinement fusion") have a very high Isp (3000 seconds for ion motors, up in the mid 100,000 seconds for fusion motors) but generate very low thrust.
The stream of particles these motors produce move very quickly, but there aren't a lot of them.
Why is a high specific impulse a Good Thing?
Recall Newton's Third Law of Motion: Every reaction produces an equal an opposite reaction. Simply put: In a rocket, the momentum of the stuff the motor accellerates out the back ("reaction mass") translates into forward momentum. The faster the stuff you toss out the back, the more bang the buck you get out of that mass.
A higher exhaust velocity means you need less reaction mass, in terms of the percentage of your starting total mass, to achieve the same changes in velocity.
Here's the rocket equation:
M(f)+M(0)
--------- = e ^ (Vd/Vex)
M(0)
M(f) = mass of fuel
M(0) = mass of space ship w/o fuel
e = natural log number, about 2.718 is fine for these purposes
Vd = desired velocity change
Vex = exhaust velocity
The "velocity change budget" for a fast trip to Mars is about 20 kps. The exhaust velocity of a good chemical motor is about 5 kps. If you plug these numbers into the above, you find you need a mass ratio of 54:1 for your Mars trip. That is, 53 tons of fuel for every ton delivered to Mars orbit. With a nuclear fission rocket motor with a exhaust velocity of 10 kps, the mass ratio is more like 7:1.
Stefan " I'm not a rocket scientist but I play one on TV" Jones
"Per booster" is meaningless in this context.
The specific impulse (measured in seconds) remains the same no matter how many boosters there are.
You could gang together several motors to increase the delivered thrust, but the exhaust velocity would remain the same.
I couldn't find a figure for Isp on the research site linked to. The second article suggests an Isp of 3,000 seconds for his "lightbulb" motor, but that sounds awfully high for a fission rocket.
Stefan
"FA-THER! GIVE ME LEGS!"
. . . like orienteering, starting fires with sticks, learning how to walk on dirt, and not petting badgers.
Stefan
Those aren't "certainties."
You are repeating FUD churned out by outfits like the American Enterprise Institute, Greening Earth Society, and other well-paid advocacy outfits.
Every one of these factoids has been disproved.
The vast majority of scientists agree that global warming is real, and that human activity is a major factor.
Through sheer volume and persistance the patsies of the fossil fuel lobby get their distortions onto editorial pages. They've fooled politicians, and lots of the public, but they can't fool Maw Nature, who can be a real bitch.
Stefan
Because mostly that's all there is. Later probes might be able to roll or fly to interesting, spectacular places, but for now they are playing things safe.
". . . we're still sending probes!"
Well, yeah. Probes are cheap and have a high Find Things Out For The Buck ratio. There is a lot about Mars we simply don't know, including important things like how much water there is and in what form it is.
We have to know about these things before we can plan manned missions. Hyper-enthusiasts will tell you we can go to Mars tomorrow and create self-sustaining habitats the day after, but they are way full of it, cutting every corner and making every most optimistic assumption. (They're a lot like the L-5 enthusiasts of the 1970s. Anyone else remember them?)
Before you walk, you gotta learn to crawl.
Earthlike atmosphere? No, because Mars is very short on volatiles. Yes, there may well be enough water for a few small seas, and enough CO2 to create a thin atmosphere. But there's little or no nitrogen, and you'll have to crack the CO2 to create oxygen. And, I suppose, Ozone to screen out the U.V. And maybe how to create a magnetosphere from scratch to divert the solar wind.
Terraforming Mars would take centuries and probably involve importing gasses from moons and comets Out Yonder, and successive generations of tailored life forms to do the dirty work.
Stefan