h a l f b a k e r y"It would work, if you can find alternatives to each of the steps involved in this process."
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(1). Let a hydrogen balloon carry the launcher to about
80.000
meters.
(2). The launcher is a vertical tube with about 100 ring-
formed
directed explosives all around it (or plain dynamite would
do). The space vehicle is drop shaped construction with a
hard
solid backend,( the tail
of the drop).
(3). The vehicle is squeezed like a bathroom soap as the
explosives "in turn" go off, one after the other and
synchronized with the accelerating soap/vehicle pushing
mainly on the hard solid backend of the vehicle.
(4). A 20 meter tube would easily accelerate the vehicle to
escape velocity, (shot through the ballon by the vertical
pipe).
(5). Vehicle is accelerated to escape velocity of earth but
below velocity for earth+moon, and if it is just vaguely
pointed towards the moon, the moon will catch it.
(6). A wire is ejected and by
electromagnetic induction (earths magnetic field) and heat
radiation, it is slowing the vehicle down until it eventually
crashes on
the moon. It is made to withstand the crash and to bounce
on
the surface.
(7). When it has come to a stop a rolling robot is released.
(8). It is an inflatable robot inflated with a tiny helium
pressure from a tank.
(9). Each wheel is painted black and white in such a way
that
the the sunwind and radiation pressure get the wheels
rolling, like a Crookes radiometer.
(10). A Ball is inflated, half of it is transparent and half is
silver coated. It has a filter coating reacting to the
radiation
pressure from the blue earth and will start to adjust itself
pointing towards the earth by radiation pressure.
(11). The now directed ball will work as an approximate
antenna for sending the video signal back to earth (from a
small video camera.)
How does a light-mill work?
http://math.ucr.edu...ill/light-mill.html
[spidermother, Sep 25 2013]
N-Prize
[FlyingToaster, Sep 25 2013]
Similar idea I had for achieving high velocity projectile
Explosively_20confined_20gun_20barrel
I had a similar idea a while ago, posted it originally on one of the n-prize ideas as an option for final-stage propulsion. [Custardguts, Sep 26 2013]
High velocity manhole covers
http://nuclearweapo...lumbob.html#PascalB
Didn't hit Mars. Didn't escape Earth. Didn't orbit Earth. Didn't leave the atmosphere. [lurch, Sep 26 2013]
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Annotation:
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What [FlyingToaster] said, except I find that double line-break characters work even better (just hit <enter> twice). |
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Why would you inflate the robot with Helium instead of Hydrogen ? |
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Why would you want to go to the moon anyway ? It's a dump. |
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Radiation pressure almost certainly won't be a large
enough force to do the alignment thing, and you may
be forgetting that the Moon's surface is very dusty,
electrostatically dusty, and sticks to everything. The
dust will interfere with any attempt to use radiation
pressure. |
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Hi,
Thanks for the input, I have cleaned it up.
I hope it is easier to read now... |
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The robot is filled with helium and the initial lift
balloon; hydrogen (for maximal altitude). |
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I have some drawings, the "antenna-balloon" is
simplified in the description above, the idea was to
somehow use the sun-wind to lift it (kite?) while the
angle is such that the transparent part is facing earth
(to prevent it from tracking the sun.) However, that
would require releasing the ballon at a certain
moment which I would like to avoid. |
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The challenge I played with was to have it
autonomous without electronics (except for the
video camera). |
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I did most of calculations a year ago and the "soap"
seems to be feasible. |
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I would guess that radiation pressure would be
enough, for a lifted balloon in a string, |
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Judging from a Crookes radiometer. |
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The wire's an interesting idea for a brake. So's the soap method of initial propulsion. |
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I'm a bit skeptical that you're going to accelerate or decelerate as fast as you want to without totally trashing anything inside the craft, or the craft itself. |
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Problem with high explosives is they can set each other off from shock. So your //20 meter tube// isn't going to work, far as I can tell [edit: oh wait]. And the current balloon altitude record is 53k meters. |
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[+] It may only cost $100k to make the final version, but R&D will likely run into the millions. |
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I don't see any problem with (2) and (8). |
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So, we've narrowly exceeded Earth-escape velocity - I get that part. What, though, is this "Earth+moon -escape velocity"? Presumably, you mean we're not going so fast that the moon's gravity is unable to pull us back in - but how fast that is surely depends on how close to the moon we're heading *before* we start to feel its pull. |
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If our vehicle had just barely enough velocity to escape from Earth, I'm guessing (on the basis of no maths, not even on the back of an envelope), that we'd still have to aim within a fraction of one degree of arc of a direct collision course before the moon had any chance of "catching" us. I doubt that "pointing vaguely" would do it. |
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But, by all means, do the maths and prove me wrong. |
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The depth of the earth+moon gravity well is deeper
than the earth-only gravity well in all directions.
However, in most directions, the difference would
be a helluvalot smaller than the lack of precision in
this idea. |
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Beyond that, for the vast majority of that gravity
well, the earth is the local minimum, the deepest
spot in the gravity well. So you have to go over the
ridge into the area where the moon is the local
minimum; you'll then have all the potential energy
necessary to get back out, unless you stopped at the
top of the ridge and slowed down some more on
the trip (or pash into the side of the moon, direct,
incavate). Remember Apollo? "Free return path", it
was called. |
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"Electromagnetic induction" doesn't work with the
earth's magnetic field for slowing down in the
vicinity of the Moon, because the earth's magnetic
field isn't there. "Heat radiation" is an infrared
herring. |
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A Crookes radiometer isn't driven by radiation pressure (link). |
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I thought that someone around here had shown that explosions are inadequate to propel something to escape velocity. Or is it that the angle coming from the ground is wrong to achieve a stable orbit? |
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The example is usually the legendary manhole cover propelled into orbit by the early H-bomb tests. |
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//The example is usually the legendary manhole cover propelled into orbit by the early H-bomb tests.// That manhole cover reached escape velocity, so orbit is not a factor. It's probably on Mars by now. Putting something in actual orbit with explosives would be more difficult and expensive than just using a rocket, but there is no reason why it's impossible. |
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// Let a hydrogen balloon carry the launcher to
about 80.000 meters.// |
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As a minor point, I think 30km is about the limit
for hydrogen balloons that carry useful payloads.
Beyond that, the extra mass of the envelope
needed starts to outweigh the lifting capacity of
the gas. (I see the "53k metres" comment above,
but that balloon carried only 4kg of instruments.) |
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[janpeternordin] have you seen the N-Prize? |
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//explosions inadequate ... orbital velocity// true in that high explosives' propogation speed is a tad less than that required for escape velocity... except for the soap thing which translates as "tacking in 3 dimensions" (which I've never heard of before and is extremely cool so [+]). |
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//angle// more true except he's not trying to escape Earth's gravity, just make it as far as the Earth-Moon gravitational null point, at which time the Moon can take over, in the same manner that, if you want to just get the ball into the basket, you can toss it up in the air using a small amount of energy instead of having to kick it sidewards at a bit greater than orbital velocity. |
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No clue personally if the calcs actually work for the above. |
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This is quite a lovely delerium, may I join you? |
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depends... wots a "delerium" ? |
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See [link] for similar idea I had a while ago. The mechanism I was proposing was gas pressure not "squeezing", otherwise essentially the same. |
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Be cool to see if it could actually work. |
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Not sure about the rest of the idea. |
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I think it was one of those giant marsupial ground
sloths, extinct about 20,000 years ago. |
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//extinct about 20,000 years ago// right... in that case what's that living under my porch ? |
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"soap" - well mostly what [8/7] said in [Cg]'s idea though they aren't really the same except for the "squish stuff inwards to make other stuff pop out the end". |
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In this case the bullet needs a running start to get up to the velocity where a low-explosive deflagrant as the first explosive takes over. There is a certain amount of inherent self-correction of small errors if there's a gap between the ring (aka "tube'o'boom) and bullet. |
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Initial acceleration of the payload can be achieved using a recoilless mechanism like the Davis gun. That will give you initial translative velocity. The payload then passes into a region where a Lyman-Haskell system takes over, but could use radial implosion to provide longtitudinal impulse. |
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Unless you've a brace of Davy Crockett heads, I don't see how L-H is going to get you to escape velocity. Though, strict escape velocity is probably not necessary: you only need to get up to the Earth-Moon null point. |
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// a brace of Davy Crockett heads // |
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We only sell them by the dozen. |
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// I don't see how L-H is going to get you to escape velocity // |
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Very long barrel, lots of side chambers. Theoretically ... |
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Ok, so it went pear-shaped for Adolf and Dr. B ... but the theory is sound. |
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/ I don't see any problem with (2) and (8).
— lurch, Sep 25 2013 / |
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7 is cool with me. I like 7 a lot. |
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okay, I'm feeling better now. |
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//Theoretically// a cylinder which composition transitions smoothly from low-explosive at one end to high-explosive at the other exponentially by velocity (gotta do it that way because the tail isn't shape-variable), resulting in a smooth transfer of energy and minimal delamination of the projectile's surface. |
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Realistically, at the first mixture anomaly the wave goes pear-shaped and stays that way through the rest of the blow and you're apologizing to somebody halfway'cross the continent about their shed. |
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So, as far as I can tell, it has to be a series of wavefronts with enough of a separation mechanism to keep malformations from proliferating, ie: it can't be continuous and you need something between rings to keep the next one from being set off prematurely. |
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Which is what the idea said. |
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I will donate $10 to anybody who promises to accidentally take out an ugly public statue, parked minivan, or telecommunications satellite with great prejudice during testing/operation. |
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$20 if there's live footage. |
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Thanks for all the comments.
I agree to the sensitivity of the moon+earth gravity
well. To be robust, I'd guess, the magnetic break
wire must be released somewhere between the
earth and moon to slow the vehicle down enough to
avoid a sling shot return to earth.
It will then be much more likely to go into mooon
orbit |
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A cannon start of the flight is an excellent idea. |
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It is true that the radiometer does not work by
radiation pressure but as an effect in a near vacuum
gas. That would potentially make it useful for
powering the robots inflated transparent inside i.e.
wheel and anything inside robot with the low
pressure helium gas. I agree that it would be difficult
to use it in the space vacuum i.e. on the moon. On
the other hand there the sun wind probably could be
used, it should have full force on the moon since it
has no magnetic field. |
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[[[this was my first posting and I must say I was
impressed by the useful high quality feedback...]]] |
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crowd-sourcing? ...anyone...? :) |
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The escape velocity is due to the high-pressure and
high acceleration of explosives (compared to i.e. gun
powder.), Eventhough not all of the energy will be
efficinetly spent. The cargo- folded inflatable robot -
could be made to withstand the enormous
acceleration. |
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Yes, you need high-explosives 9 km/s + |
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"In a high explosive, the gas pressure is strong
enough to destroy structures and injure and kill
people. If the gas expands faster than the speed of
sound, it generates a powerful shock wave. The
pressure can also push pieces of solid material
outward at great speed, causing them to hit people
or structures with a lot of force." |
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The solar wind would indeed be as great on the
moon as in space. But (copied from Wikipedia): |
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"The [solar] wind exerts a pressure at 1 AU
typically in the range of 1–6 nPa (1–6×10^-9 N/m2),
although it can readily vary outside that range." |
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"Solar radiation pressure ... perfect reflectance: F
= 9.08 uN per square metre (9.08 uPa) (normal to
surface)" |
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Unfortunately, you would have a very hard time
orienting something passively on the moon using
the sun's photon pressure directly. Solar wind or
light from the Earth exert vastly less pressure
again. |
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// you're apologizing to somebody halfway'cross the continent about their shed // |
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Never apologize, never explain ... for a start, they're likely to take it as an admission of liability. |
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// I will donate $10 to anybody who promises to accidentally take out an ugly public statue, parked minivan, or telecommunications satellite with great prejudice during testing/operation ... $20 if there's live footage. // |
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How much will you pay for an anonymous YouTube posting ? |
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<ponders the Borg insurance racket: "wun't it be a right shame if an asteroid wuz to crash on youse nice planet there"> |
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//A 20 meter tube would easily accelerate the
vehicle to escape velocity, (shot through the
ballon by the vertical pipe).// |
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//The cargo- folded inflatable robot - could be
made to withstand the enormous acceleration.// |
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Escape velocity is something like 10000m/s. That
means an acceleration of 250,000G. For example,
a bolt weighting 1 gram will put a loading of 250kg
on the surrounding structure. |
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