Skip to comments.Griffin Tells Astronomers To Lower Expectations
Posted on 01/16/2006 9:53:39 AM PST by Paul Ross
Aviation Week & Space Technology
Griffin Tells Astronomers To Lower Expectations
By Frank Morring, Jr.
LOOKING TO THE STARS
Astronomers in the U.S. can still look forward to a human servicing mission to the Hubble Space Telescope next year, and perhaps to big observatories on the far side of the Moon some day.
But for the most part, the funding outlook at NASA for space science is tight as the agency shifts its focus to sending humans back to the Moon, meaning near-term priorities like searching for Earth-like planets around other stars will slip, and it will take longer to begin answering new questions like "What is dark energy?"
"NASA simply cannot accomplish everything that was on our plate when I took office last April," Administrator Michael Griffin told the American Astronomical Society (AAS). "In space-based astronomy, as in other areas, we will have to make tough trade-offs between maintaining current missions--of which there are 14 ongoing--and developing new capabilities."
Griffin drew applause when he reminded his audience that he reversed a decision by his predecessor not to send another space shuttle mission to service the Hubble telescope, which continues to produce important new discoveries.
But he cautioned that the final Hubble servicing mission, tentatively scheduled before the end of next year, will be launched only "if at all possible." And he said bluntly that there is no way from an engineering standpoint to mount a robotic servicing mission, as former Administrator Sean O'Keefe opted to do, that could do more than deorbit the telescope safely before it is expected to become uncontrollable.
The fate of the Hubble--and a lot of NASA's other programs--will depend on White House funding decisions due for public release with the Fiscal 2007 budget next month. Griffin conceded, "I do not know in all its details what it will contain," which suggests a debate is still underway within the Bush Administration on how to cover a shortfall of at least $3 billion in the shuttle program (AW&ST Nov. 7, 2005, p. 40).
"By any measure, one would have to say that the growth of science in NASA has been in the 5-7% range, annualized, over the last decade or so, and that's all been great," Griffin said. "We're in a budget environment now where that level of growth can't be maintained, although science at NASA will still have growth."
SOME OF THAT GROWTH will be absorbed by the James Webb Space Telescope, the top space mission in the U.S. National Academies' decadal list of astronomy priorities. Terming the $1.5-billion shortfall in available funding for the mission "under-costing" rather than an overrun, Griffin said his agency has a better handle on the cost of the deep-space infrared observatory. Launch of the Webb telescope has been slipped from 2011 to 2013 to cover the extra cost without hampering its ability to peer back to the earliest galaxies in the Universe, and penetrate closer dust clouds to watch star formation within.
Under questioning from AAS President-elect J. Craig Wheeler of the University of Texas, who collected queries from members, Griffin said the problems with the Webb observatory will force a delay in starting the Space Interferometry Mission (SIM) and its successor, the Terrestrial Planet Finder, both National Academies priorities designed to find Earth-like extrasolar planets.
Griffin noted that President Bush's human-exploration directive has raised concerns in all of the communities of scientists who use NASA systems in their work, and vowed to do what he could to keep the disruption to a minimum.
"Our cost estimates for returning astronauts to the Moon are conservatively structured to achieve our goals within budget," he said. "Also, while we certainly are not claiming cost savings that have not been proven, we very much intend to find ways to reduce the cost of the exploration program through improved technology, commercial involvement and international partnerships."
And in the long term, he said under Wheeler's questioning, astronomers may some day find the Moon a better place to conduct their business than Earth orbit or the L-2 Sun-Earth Lagrangian point where the Webb observatory is bound. The Moon's far side offers a much quieter environment for radio telescopes, and many types of sensors could be laid out in arrays on the Moon for higher-resolution imaging than is possible on Earth.
"I would argue strongly with those who assert that human spaceflight is inimical to science," he said. "Our scientific initiatives go hand in hand with our extended reach into the Solar System. It is not our desire to sacrifice present-day scientific efforts for the sake of future benefits to be derived from exploration.
"A stable platform like the Moon offers advantages in the engineering aspects of astronomy that are hard to obtain in space."
His views on using the Moon as an observatory notwithstanding, Griffin ducked a question from Wheeler on whether it would be worthwhile for U.S. astronomers, working through the National Academies, to reconsider their priorities in light of the new possibilities raised by the exploration initiative, or by recent discoveries.
"I think the astronomy community has to decide for itself whether the priorities have changed enough to warrant doing a decadal survey in an off year," Griffin said.
One thing pushing astronomers to change their priorities is the discovery of a mysterious force driving the expansion of the Universe at a rate that appears greater than can be explained by what is visible to telescopes like the Hubble and the most advanced ground-based instruments. The force, dubbed dark energy, was confirmed after the astronomy priorities for this decade were set. A National Academies panel created for the job stopped short of recommending that new priorities be drafted.
INSTEAD, THE PANEL called for "balanced" planning of future astronomy missions, with a greater role for the U.S. Energy Dept. and greater use of Explorer-class space missions. And it cautioned that slips in programs growing out of the exploration initiative could "adversely affect NASA's ability to generate the kind of transformative science that is the hallmark of the past decades."
NASA is already working with the Energy Dept. to draw up a Joint Dark Energy Mission, for which concepts are due in March. Among them is the SuperNova/Acceleration Probe (Snap), a two-meter space telescope (see artist's concept) that would continue detailed measurements of the Type Ia supernovae that provided evidence the Universe is expanding more rapidly than thought.
But with the science budget already squeezed, and the possibility of more budget cuts in the offing, it is unlikely that new starts like Snap will be funded, regardless of the science they produce. Indeed, senior astronomers like Wheeler, are worried they won't be able to fund graduate students today who will be called on in the future to make sense of dark energy and other new questions.
"We're all holding our breath, waiting to see what the budget's going to be," Wheeler said. "The budget for NASA is probably not going up. The budget for the science division is almost certainly not going up. The question is whether it will go down."
In other words, real science can expect to suffer (as always) because it's important to maintain the illusion of a manned space program.
Wonder if I'm the only person that is completely "mehh" about man returning to the moon?
Really has no interest for me at all. I'd be 1000 times more interested in a robotic probe drilling the ice of Europa and entering the (presumed) ocean below it.
> I'd be 1000 times more interested in a robotic probe drilling the ice of Europa and entering the (presumed) ocean below it.
Why? Man on the moon has the potential of expanding human civilization. Robotic missions serve only two purposes:
1: Preparation for sending Man
2: Pretty pictures.
We can buy anything in America.
Translation: "You can ask for Pluto, but we're gonna hand you Uranus..."
Been there, done that, back in the 20th Century. Manned space exploration should be left to third-world countries like China who feel a need to play catch-up.
America's armchair Captain Kirks need to face up to the fact that it's time to move on. If they want to keep playing, they should play with their own money.
Lower as in Beneath the Moon or Just Over Everest?
Nope. The Moon And Mars boondoggle is going to kill NASA. Anytime the politicians get involved there are big problems.
The exception was the Apollo program, but the bureaucrats weren't entrenched yet and NASA had a blank check to overcome FUBAR's like Apollo 1 and Apollo 13.
YES!! Needs repeating
Low as in the Calypso tune, "How low can you go?"
That goes double for the nutjobs with dreams of colonizing space.
Sub the work out ...save 50% and use that for more projects.
Well the Astronomers should pay their own way also..
Lowering expectations doing the limbo actually means raising them.
They believe they should be in control of space.
With your posture of retreat, it would basically not be a challenge for China to not just "catch-up" but surpass...then actively DENY us access to space.
I know this is too long a view for short-sighted minds to digest...but that is their view.
There are those who get their property tax notification today and immediately begin a rant, but never get around to going down to the tax hearings to get their assessment reduced.
There are some practical things to do, but pointing with dismay isn't one of them.
Got my eye on that one. I fell out of the astronomy hobby a while back but this might just get me back in.
They have all sorts of dreams, but they can't tell the difference between science fiction with science.
We have frigid deserts here on earth with air you can breath and 1/1000000 the cost to get there, but there isn't much interest in living there (except for a few government grant supported scientists in Antartica and a few Eskimos in the far north)
I'm all for space exploration as long as the funds to do it come solely from the people who want it done.
The first people to establish a stable base at the lunar pole (where the ice is) will own the next century.
NASA seems to be doing the right thing, bizarrely - though probably too expensively as usual. Anyway: science is one thing, but the high ground needs to be seized.
> I'm all for space exploration as long as the funds to do it come solely from the people who want it done.
So... should we sell Alaska and the Louisiana Purchase back?
Heinlein's The Moon is a Harsh Mistress is science fiction.
And this is relevant because....?
You nailed it. I believe that the water ice at the lunar pole will form the basis for future solar system resource development - it will be a "Panama Canal" style bottleneck for a hundred years. Consequently I would rather America owned it than the UN or the Chinese
Yeah, but the nuttiest of the nutjobs want to colonize space in order to -- get this!!! -- prepare for the day when we're forced to abandon planet earth.
Then form a company to exploit this. Raise the capital from like minded people who think the way you do, built a space ship and then sit back and make a fortune when your dream materializes (or not)
A valid question. Goes all the way back to the adoption of the new Constitution in 1787. Two radically opposed factions in FedGov, not even civil war put an end to it. Remember: almost every bridge was a Bridge to Nowhere at the time it was built.
I've gotten into "discussions" with them before. It's a religion with them. Facts are not welcome. They are true believers. As I look around the solar system, I don't see any place that will support human life except good old earth.
C'mon, Dude, you're just no fun at all. We can do anything given enough imagination and (other people's) money. Besides, you're not looking far enough. There's got to be another solar system out there. "To infinity and beyond!"
If you cut the income tax by 50% and cut nasa to zero except for voluntary contributions, there would be more than enough money.
That day will come. It may not be for one or two billion years, but it will come.
Gosh, you're right I forgot the O'Neal colonies and the Lunar domes. Shouldn't take more than two or three time the total annual GDP to establish these (Well considering that government at all levels consumes over half of it now, maybe a bit more than that)
So was going to the moon ... until we went to the moon.
So? The science is real:
§ 3.4.3 Lunar Launch by Mass Driver "Slingshot"
The "mass driver" is a "catapult" tube which launches materials from the lunar surface to a Catcher/Collector, perhaps near a factory in orbit near the Moon. The mass driver is like a gun without the explosive gunpowder. It is powered by electricity, producing magnetic fields to accelerate cargoes through an accelerator tube. No fuel propellant is required for lunar launch, and there's no big vehicle to launch. The mass driver shoots a large number of small payloads, continuously, rather than an occasional large payload.
Mass driver on the Moon. Source: SSI (www.ssi.org)
The mass driver will eventually become the main means of supplying material from the Moon to industry in orbital space, though not in the early years of space development. It can help preserve the lunar environment by reducing the creation of a tenuous atmosphere from rocket fuel propellants, and it saves on the consumption and costs of producing fuel propellant. It can be argued that the mass driver can ship materials in much larger volumes than is feasible by chemical rocketry, and at lower costs per unit mass.
The "mass driver" has been a popular lunar launch concept, largely due to promotion, research and development by the Space Studies Institute (SSI). A laboratory prototype of the accelerator section has been built and tested successfully by SSI.
Powered only by electricity, it is a solar powered launcher using the principle of electromagnetism to magenically accelerate a payload equipped with a magnetic bucket to excape velocity.
It has been argued that the mass driver is a relatively inexpensive and automated device to create a stream of material at the rate of up to a few small packages per second, depending upon design. Total amount of material deliverable each month could dwarf any feasible lunar or Earth launch capacity by rocketry, in terms of tonnage of payload launched.
As it is covered most prevalently in the literature to date, minerals mined and processed are packaged in a thin glass/fiberglass bag easily manufactured using lunar materials. The bag is made to conform to the shape of the bucket so that the bucket assumes the stresses during acceleration, whereas the package contains the minerals after acceleration and snapout from the bucket.
By the time the payloads climb up out of the Moon's gravity well, they have lost most of their velocity and are travelling slowly. At this point, the orbital-based catcher collects them. The payload material's momentum carries it through the funnel-shaped catcher into a collector bag. After the bag fills up, it is detached from the funnel and is replaced by an empty bag.
The mass driver accelerator tube would be less than 200 meters (600 feet) long and probably about half a meter wide, though downrange trajectory correction equipment will probably be worth the cost. The mass driver would fit into only one Shuttle cargo bay, disassembled, not including power plant, material handling apparatus, and fuel for delivery. The electric power plant size determines the launch RATE, not ability -- a small rate initially, increasing permanently with more power modules and support apparatus.
Unfortunately, the mass driver is feasible to operate only on the Moon, because it needs vacuum. A mass driver operating on Earth would cause meteoric friction heat to such hypervelocity payloads and great physical stresses, at the dense bottom of Earth's atmosphere (ocean of air) as they left the catapult tunnel. Secondly, the air would aerodynamically deflect such objects in unpredictable ways which would disperse their trajectories. Thirdly, an operable mass driver on Earth would require a long vacuum tunnel (much longer than on the Moon, since the escape velocity is higher). Fourth, the air would create hypersonic sonic boom shockwaves that would be loud for a long distance. Fifth, individual payloads would have to be massive enough to punch through the atmosphere in an acceptable way. Such massive payloads demand alot of the catapulter as well as the orbital based catcher/collector.
In contrast, the Moon has no air and low gravity.
The orbital-based Catcher/Collector would be located in lunar-stationary orbit (the "L-2" or "L1" point), where it would collect the stream of numerous small payloads after they slowed down in climbing up in the Moon's gravity well. Various catcher/collector designs exist.
Pollution of space should be avoided, so the containment of material is important. If a package misses the catcher, it should return to crash on the Moon, not orbit Earth. This must be built into the trajectory design.
A number of bottom-line facts about the mass driver for space transportation :
The mass driver, as you can see, is an entirely different kind of launching device.
With the advent of space-based industry and the demand for products and materials, the small step of basing a mass driver on the Moon will be a giant leap for the eventual low cost transportation of material to space, and will make the Moon more competitive as a source of materials compared to asteroids.
However, it is my opinion that the mass driver will not be used until large scale space infrastructure has been established. It is my opinion that a successful, privately funded investment into lunar materials would need a strong case for the reliability of the mass driver before it would use or invest in development of a mass driver over chemical rocketry. If the mass driver in its popular implementation -- pull-only with no magnetic levitation guide strips -- were put on the Moon and something went wrong with the launch so that the bucket coil scraped along the wall of the tunnel at anything near its terminal velocity (2.4 km/sec), the mass driver could sustain major damage, delaying delivery of material for a significant time unless there were good repair infrastructure already emplaced. This is a risk issue for private investors. Before the mass driver is developed further, a good, peer reviewed case must be made for its reliability. Notably, a safer, more robust design may be more attractive, e.g., using magnetic levitation guide strips, even it it's significantly less efficient and more expensive.
In comparison, chemical rocketry has its risks in terms of rocket engine failure. Regarding the latter, rockets for launching off the Moon are significantly safer than rockets launching off of Earth because the Moon's gravity is much less. The lower gravity has a compounding effect: rockets on Earth have far more fuel than payload (e.g., 50 times more fuel weight than payload) -- fuel for later in the flight -- which means the Earth rocket must launch a much heavier mass than its payload. The rocket engines on the Moon need not be the very high performance ones as on Earth, and the stresses are much less.
Work to date has emphasized the mass driver acceleration coils, in order to reduce the size of the acceleration section to, say, 160 meters. No laboratory work has been performed yet on any other element, e.g., assuring the precision required to hit the Mass Catcher in orbit, though many paper studies have been performed. Notably, many designs call for the buckets to be recycled, which would reduce the cost of manufacturing bucket coils for every payload or returning bucket coils from orbit to the Moon, e.g., by chemical rocketry. If this approach was adopted, the bucket coils would need to be recycled, which gets into the very risky business of diverting high speed objects into a deceleration tunnel in a precise way, and decelerating them properly. One alternative is to launch large payloads so that manufacturing or returning bucket coils becomes economically feasible, which goes counter to many designs of mass driver to launch small payloads and keep the launch tube short and lightweight.
I've not seen a good analysis of potential failure modes or remedial actions.
In the long term, a mass driver is preferable in order to preserve the Moon's environment. The Moon has sufficient gravity to retain an atmosphere, and chemical rocketry launches could create a significant atmosphere which would take many years to dissipate if we were to later cut back dramatically on rocket operations on the Moon.
Explanations of the mass driver as developed by SSI are on the following pages. However it's worth noting that I have worked on electromagnetic launchers for the Pentagon in the Star Wars/SDI program (largely reviewing and assessing the different concepts for SDIO decisionmakers), and there are a few interesting alternatives to the prevalent "coaxial" mass driver developed by SSI.
How the mass driver works
The mass driver works by the magnetic attraction between electromagnets. One electromagnet is the bucket coil, and the other electromagnets are the drive coils.
What is an electromagnet ? Electric current in a coil of wire always produces a magnetic field, called an electromagnet, which behaves basically just like a bar magnet, except for the fact that an electromagnet can be made to be stronger than a bar magnet by increasing the electric current through the coil.
By proper orientation of the poles, a bar magnet and an electromagnet can be made to attract or repel each other. Similarly, two electromagnets can be made to attract or repel each other and hence accelerate towards or away from each other. Which side of an electromagnet is the north pole depends on whether the electric current is clockwise or counterclockwise through the coil of wire.
The mass driver works by two electromagnets being attracted to each other and hence causing acceleration. One coil is smaller than the other, and passes through the center of the larger coil. The larger coil is the "drive coil", anchored down to be stationary, and the smaller coil is the accelerated "bucket coil".
The mass driver is a tunnel of numerous drive coils accelerating a bucket coil. The bucket coil pulls a bucket of material with it.
The drive coils are not always turned on. Each drive coil must turn off its electric current when the bucket passes through its center in order not to slow the bucket coil back down on the other side by the same attractive force. Secondly, each drive coil turns on only when the bucket coil is close enough to feel the pull significantly (in order to save power), and turns off when the bucket coil reaches about the center of the drive coil. Thus, each drive coil gets only a pulse of current, when the bucket coil is closely in front of it, and must be off when the bucket coil is behind it.
The bucket coil always has current.
What the bucket coil "sees" as it travels down the tunnel of drive coils is a series of dead drive coils each of which suddenly turns on quickly when the bucket is very close, and then turns back off by the time the bucket coil passes through the exact center of the drive coil. This happens for each drive coil in sequence as the bucket flies down the tunnel of drive coils, picking up more and more speed.
This version of "coaxial" mass driver is called a "pull-only" mass driver, because the bucket is pulled by magnetic attraction but is not pushed by magnetic repulsion. Other versions exist, such as pull-push, which we won't consider here. With the pull-only mass driver, no mechanical guidance means is needed to keep the bucket from crashing into a drive coil because the pull-only magnetic field of the drive coils strongly forces the bucket to levitate along the center of the drive coil tunnel. The drive coils are side by side; in fact, and the next can turn on before the previous one turns off.
The technical details of the mass driver won't be discussed in this nontechnical brief (e.g., drive coil kilohertz halfwave power pulsation, capacitors, bucket current induction, etc.). Suffice it to note that a prototype mass driver accelerator tube was built and tested successfully by the Space Studies Institute of Princeton, N.J., with lunar duty as its objective, and produced an acceleration 1,800 times Earth's gravitational aceleration. A lunar-based mass driver accelerator can be built using present-day off-the-shelf technology, but other parts of the mass driver need to be developed.
Next, an overall view of the mass driver on the Moon will be given.
Operating the mass driver on the Moon
After lunar soil is excavated, transported, refined using simple conventional means, packaged, weighed, and made to be of precise weight (e.g., added molten glass weights). The packages are loaded into buckets with bucket coils. The buckets are emplaced in a special device in front of the first drive coil, and current is induced in the bucket coil.
The drive coils are fired in sequence, with the aid of "electronic eye" sensors to trigger the drive coils and monitor the location of the bucket for adjustment in timing if necessary. The drive coils induce further current in the bucket coil.
After the bucket leaves the accelerator section, it is travelling at lunar escape velocity. Even though the mass driver is horizontal, the bucket and payload would not fall to the ground because of its high speed and the Moon's curvature and low gravity.
Immediately after the acceleration tunnel is a payload snapout and bucket diversion section, where the bucket is magnetically decelerated to separate it from the payload (which isn't decelerated and hence leaves the bucket behind) and to make the decelerated bucket fall downwards in the lunar gravity to a lower tunnel track to get out of the way of payloads coming behind it. Magnetic levitation guide strips will be required here.
The bucket is then decelerated magnetically on the lower track and returned on a parallel track to be reloaded with another payload.
The mass driver's deceleration section converts the bucket's momentum back into electrical energy as it slows it down, by "regenerative braking", using the same fundamental principle as electric generators. In fact, the decelerator is a generator while the accelerator is a motor (a linear motor instead of a rotational motor). By getting electrical energy back out of the bucket's momentum, the overall efficiency of the mass driver remains between 70% and 90%, depending on the details of the design.
In the deceleration section, the bucket requires magnetic guide means to prevent it from striking a drive coil. The well known principle of magnetic flight (i.e., passive magnetic levitational guide strips) would prevent any mechanical rubbing.
Very important is the need for payloads leaving the mass driver to have precisely the same velocity so that they all go to the same place in orbit and so that the catcher/collector can be of reasonable size. Very small variations in speed or significant lateral velocity can make payloads miss the catcher/collector. Thus, it is desirable to have a way of correcting trajectories after payload snapout from the bucket.
Downrange trajectory correction stations are possible for a horizontal mass driver. Several methods have been proposed for both trajectory determination and correction. Trajectory determination can be done by radar or laser ranging. Trajectory correction may be achieved by electrostatic means, or puffs of air, or by striking the side, front, and/or back of the payload with a low power laser or particle beam to boil off a thin layer of the payload's outer skin to create an action-reaction impulse sufficient to prevent the payload from missing the catcher/collector in orbit.
It's important for the mass driver to maintain consistency so that payloads all go to the same point. It may not be necessary to predict that precise point in advance and then try to adjust the mass driver, but it is important that the mass driver be consistent wherever it may be firing payloads. Once the mass driver starts shooting payloads, it may be necessary to move the catcher to adjust for design imperfections in the mass driver. In other words, instead of putting the catcher at the ideal point and then working to make the mass driver shoot that point, we would just shoot the mass driver and then move the catcher to where the stream of payloads is going. Further, as the sun slowly moved relative to the Earth and Moon, the stream of payloads would also slowly shift, requiring the Mass Catcher to follow the stream. Thus, what is most important is that the mass driver be consistent in producing a narrow stream.
The catcher could be located at the so-called "L-2 point" or "L-1 point in orbit, as discussed in the section on Lagrangian libration points. In short, the L-1 and L-2 points in orbit are stationary relative to the Moon's surface so that the mass driver is always shooting at the same point. The L-2 point acts kind of like the top of a gravitational hill that isn't very steep, so that one doesn't have to be stationed at the absolute balance point on top to be sufficiently stable for economical stationkeeping.
The propellant needed for station-keeping and maneuvering would not be very large. The payloads would arrive at about 70 meters per second, so they push the catcher around a bit. For example, it has been proposed that a stationkeeping device shooting slag pellets out at a velocity 30 times the incoming payload velocity (i.e., 2100 meters per second) would theoretically be able to compensate entirely for this momentum transfer at a 1 to 30 ratio of propellant to payload. As for polluting space with propellant pellets, the ejection speed of 2000 meters per second easily escapes the Earth-Moon system, and does not add significantly to the quantity of rocks naturally populating space. Of course, slag pellet shooters aren't our only option, and gaseous propellants are much more efficient since they have much higher exhaust velocities.
It has also been proposed that the catcher be stationed in a lunar-synchronous position whereby it would fall down towards the Moon except for the throughst produced by the incoming packages impacting it.
For technical information on the mass driver in particular, one may wish to contact the builders of the laboratory prototype lunar mass driver, The Space Studies Inst., P.O. Box 82, Princeton, N.J., 08540, (609) 921-0377, firstname.lastname@example.org and http://www.ssi.org
(The founder of PERMANENT, Mark Prado, did research on electromagnetic launchers as part of the "Star Wars"/SDI program, and also on mass driver power conditioning systems. As a humorous aside, in my office I had a miniature mass driver quickly made from cheap parts, charged by a regular batttery, and sized to shoot caps from coke bottles. When friendly associates would enter my office, I'd shoot a bottle cap at them.)
Are you saying that you think that all science fiction will come true (if you just close your eyes and wish hard enough)?
The previously issued posting was supposed to allude to the proposal's author at the top to prevent confusion:
I.e., source: Mark Prado...for whom I take no credit for his bottle-cap flinging sense of humor... :-)
I lean towards flinging paper clips at my overly serious colleagues.
The Adirondacks are composed of essentially the same rock as the lunar highlands as well; granted, it's a park, but if we were really desperate for anorthosite (it's a low grade aluminum ore, basically, not nearly as good as bauxite) it would be about a million times cheaper to get it from there than it would be the moon.
And the lunar maria (low dark areas) are basically the same as the huge basalt flows like the Columbia flood basalts or the Deccan Traps or whatever.
plus the article glosses of such things as With the advent of space-based industry and the demand for products and materials,
What spaced based industry? There isn't any and statements such as "After lunar soil is excavated, transported, refined using simple conventional means
Like this was a mere bagetelle. Iron mills on the moon? Go to any big industrial plant, and then look at what feed it and what feeds that and so for. Try reading Leonard Reeds, I pencil to get an idea of what an industrial base is.
This article is science fiction again.
> Heinlein's The Moon is a Harsh Mistress is science fiction.
Yep. So is cloning, space tourism, pocket calculators, color TV, nuclear power, communications satellites, intercontinental rockets, supersonic aircraft, coherent-light beam weapons, instant worldwide person-to-person communications...
Better just give up now and live like dirty hippies. The future is scary, and those who dream of possibilities should be shunned. Conform. CONFORM!!!
So where is the hovercar I'm supposed to have already had for 15+ years?
> So where is the hovercar I'm supposed to have already had for 15+ years?
Cancelled. The government decided that improved personal transportation technologies were less important than funding the next-generation of prescription drug coverage programs.
I neither stated nor implied that. I merely noted that lunar landings were considered science fiction at one time, and are now historical fact.
Well, duh. That's what needs to be changed:
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.