New Mars Forums

That's pretty cool.  I've always felt that any sort of space gimmick plan (not necessarily a derogatory term in this case) has got to at least get below a few hundred, preferrably one hundred bucks.  As soon as you hit that, you can start reaping the Sharper Image crowd out there with small amounts of cash to burn.  It's a steady but reliable source of income that gets milked for billions each year.  It'll never lead to a sustainable space civilization but it's a great way for a small space startup to fund larger launchers for more serious work.

I've mentioned that organic analyzer a couple of times but never posted a link to it so that's still a welcome addition.  :;):

As a rebuttal, I'd counter that we're already doing unintentional terraforming with results that could very possibly be like what you just said.  At least on Earth, we've got the luxury of only having to take small steps to correct extant problems rather than trying to revamp an entire planetary climate.

Ah, the next gen GPS.  I'm looking forward to that.  The accuracy will be much better and much better signal strength so that you can get a decent elevation reading and pick up a signal through trees.  In Washington state, with dense trees, a handheld GPS is next to useless.  At any given point in time, you're lucky if you're picking up more than one sat.  Of course, you can always go up a mountain and break out of the trees but then I can just look for freakin' landmarks the old fashined way... 

As jingoistic as it sounds, I largely agree with the assesment that the US is still king of the hill for the time being.  The ESA has had a history of abandoned projects that is at least as bad as NASA over the last two decades.  The only serious competition is China which is demonstrating a very well-thought out program and will have access to lots of capital if their economy keeps racing along like it has been.  Now if China teamed up with Russia and the ESA, I'd say we've got reason to be concerned.  However, the Chinese are a lot like us Americans and will probably be loathe to share the glory.  They're almost certainly going to go it alone like us.

OK, quantum wierdness time©!

First, I just wanted to add that time dialation by gravity is very well measured.  In fact, GPS has to take the faster rate of the atomics clocks on the GPS satellites up in orbit for the system to work properly!

Anyway, the doubleslit experiment you mention is one of the two BIG QUESTIONS of science.  The other is how to get relativity and quantum physics to talk to each other properly.

So, I realize that your book has covered this but I'll go over the experiment quickly for the benefit of others:

If you have a light source and a screen, light from the source will light up the screen - no suprise.  Now, if you place another screen in between with a square hole in it, the light reaching the final screen is shapes like a big square - again pretty obvious.  Right now, the observed phenomenon indicate that light can be either a wave or a particle, both are consistent with the observed results.

NOW, use a middle screen with a very skinny slit in it.  You'd expect that if light were composed of photons, the ones that go through the slit should project a larger version of that narrow slit on the screen.  This is not what happens.  Instead, you get a fuzzy rectangle of light that fades off towards the edges.  This can only be explained if light is a wave - waves diffract at apertures that are around the same size as their wavelength and basically reform into a new wave that heads out in all directions from the slit.

Now, use a middle screen with two such slits fairly close to each other and parallel.  What you get is a series of light and dark stripes.  This is further proof of the wave nature of the light since the two sets of waves coming from each slit are interfering with each other.  It's hard to describe this with text but imaging two sets of ripples coming from a pair of rocks dropped in a pond.  At some points, two wave crests or troughs will be at the same place and the water will go twice as high or deep.  At others, a trough and crest cancel each other out and the water sits at the normal waterline.  The light and dark stripes on the final screen are the same thing.  At some points, the waves cancel out, at others, they reinforce each other and make a bright stripe.

HOWEVER, if one turns the light source WAAAY down and then uses a sensitive camera to detect light, it becomes apparent that light is hitting the final screen in discrete places.  You see tiny flashes of light which proves that light is also a particle (photons).  Therefore, light acts as both a wave and a particle.

The really wierd parts comes to where you turn the light source almost off.  At this point, single photons are leaving the source and going theough the aparatus.  Since each photon is travelling on its own and has nothing to interfere with, you'd expect that you'd get two thin stripes of impacts representing the photons that managed to go through the two slits.

Wrong!  What happens is that if you tally up the impact points over time, you start building up an interference pattern!  The only possible explanation is that each photon interferes with itself!

Furthermore, if you monitor a slit to see if a photon goes through a particular slit, the pattern vanishes!  This self-interference effect is killed by observation!

How all this occurs is not known.  There are a thousand theories out there but I'll describe a few of the mroe plausible ones. 

First, the party line is the Copenhagen interpretation drawn up by Niels Bohr and others when quantum physics was being developed in the 20's and 30's.  It basically assuems that there are particles that turn into probability waves that go through the slits and make an interference pattern on the final screen.  The photon then automagically remanifests itself when the probablility wave collapses.  The particle location is purely a probability event - where the probability waves were 'thicker', you havea greater chance of the particle reappearing.  This interpretation also says that if you observe a system, the probability waves collapse.  The big problem that people ave with this interpretation is that it has this 'observer' involved.  What's an observer?  If a cat looks at the experiment, does it collapse?  What about before the existence of life?  Does this theory require the exitence of a God that collapsese the universe's waveforms?  Because of the poorly explained observer portion, lots of people are dissatisfied with the Copenhagen interpretation.  However, until it is disproven, it is the default explanation because it has so far stood up to all scrutiny.

There's a scad of alternate explanations involving virtual particles, radio waves travelling backwards through time and other weirdness.  However, they all share the Copenhagen interpretations weakness - they all add something to the underlying quantum mechanical equations.  Those equations never say anything about any sort of waveform collapse so any explanantion that tries to explainit ends up looking like a house with an ugly addition.

Enter the Everett multi-world hypothesis.  Everett, back in the 70's, decided to try and look at the the pure equations involved in quantum physics and see what they said, ignoring common sense requirements for waveform collapse.  He found that there is actually no reason for the waveforms to collapse.  Basically, the photon has two choices - to go through one slit or the other.  It doesn't choose - it goes through both and interferes with itself.  It hits all points of the final screen.  Basically, it's now probabilistically spread out over the entire screen in the pattern of an interference pattern.  Now an observer looks at it.  Our experience is that we see a flash of light at a point which means that the photon must have collapsed into a single point and all of the other theories assume this as well.  What Everett realized is that the human brain is just another quantum mechanical construct like anything else.  Basically, as soon as you see that photon spread across the final screen, YOU split into a basically infinite number of different quantum states.  Each quantum state sees the photon at a different location but in actuality, the photon is still everywhere.

The popular misconception is that every time there is a quantum mechanical choice, the universe splits into parallel universes.  This is a common but incorrect interpretation even among physicists.  The universe doesn't split.  Instead, all possible things occur simultaneously.  According to this model, every possible consequence and outcome that could possibly occur in this universe does occur and at the same time.  These alternate realities all coexist with each other in the same time and place but each particular reality can only see itself, giving the illusion that only one thing is going on.  Basically, that can happen, does.

This is by far the most elegant interpretation of quantum physics.  Unfortunately, by it's own rules, the Everett multiworld hypothesis can never be proven or disproven.  By definition, those alternate realities can never 'see' each other so no concievable experiment can confirm or deny this theory.

Well, I'd argue that GCNRevenger is fufilling an important task - namely keeping the rest of us intellectually honest.  If everyone is rah-rah about these ideas, it's easy to start thinking unrealistically.  Occasinally, you need a naysayer on board, even if they aren't right all the time to force you to stop and think about your ideas to form a rebuttal.  After all, as Nietzche said, "True courage is not in strength of convictions but rather the courage to question those convictions."

I used to work with a physicist that GCNR reminds me of.  He was often relentlessly negative but I really appreciated having that around.  I ended up learning most of the physics I know from hainging out with him and bouncing wacky ideas off of him and letting him shoot them down.

The laser system has had some mild success.  So far they've been able to get a 1 lb craft to about 200 feet.  Exactly how they plan to get a deent mass to LEO is beyond me.  The lase they used for that test wasa multiMEGAwatt beam.  They don't get much bigger than that.

Plus, those big lasers are just insanely inefficient - 0.1% efficiency is really good in those circumstances.

On the other hand, microwave power transmission is not a bad idea.  I read a paper - it might have even ome from Myrabo's group - that loked interesting.  Microwave transmitter arrays can hit 70-80% efficiency and move huge amounts of energy.  They basically posited an X-33 spaceplane with an H2 payload and a microwave reciever on the belly to heat that H2 up.  By doing so, they were able to theoretically get enough energy to the craft to let it get to orbit with significant payload.  (Isp was something crazy like 1700)  The only problem was that in order to get away with a single microwave emitter array, the X-33 would have had to hit an acceleration of 25 G's near the end of the boost phase.  Fine for cargo but no humans could survive that without serious injury.

There have been some tests with laser power craft.  The projectile is a pound or so and looks similar to a flying saucer.  A powerful laser is aimed at it and the back of the craft is shaped so as to focus the laser energy to a very small area.  The propulsion is either carried out by explosively heating a piece of plastic or simply heating the air.  It works but is terribly inneficient.  There are similar approaches using microwaves that have more promise for being scaled up.

I have to side with GCNRevenger on building structures with a low mass booster.  If your parts get too small, the end product is mostly composed of interconnects which is very inefficient.  Plus, in space assembly has proven to be far harder and less routine than was originally envisioned.  Until our robot capabilities get much better, it's just not too practical.

However, I'm still maintaining that booster mass is irrelevant for liquids and gasses.  Even if you're lofting 100 kg a flight, as long as your cost per kg and reliability are high, you're gold.  Let's assume for a minute that the Bull type launchers are practical and reliable.  (there's no evidence that they wouldn't be from the experience so far with such technology)  Let's also assume $500/kg per launch for a 100 kg to LEO payload and a reusable shell.  You've got some difficulties with the automated docking with so many payload but as long as you design your fuel depot to be able to shrug off minor collisions and ensure that a complete failure in the shell guidance systems leads to a miss, I don't see why this isn't a valid way to get mass to orbit.  Likewise, small SSTOs of a few MT are within our reach - why not utilize that capability?  SSTOs will not be capable of lofting structural elements anytime soon so why put that constraint on them?

Let the big dumb soosters do what they're good at - lofting big, assembled structures and let the cheap systems do what they're good at.

From a technical standpoint, I think you're being too pessimistic.  The Zenit's got nearly the cargo capacity of an Arianne 5 and a cargo diameter of 3.9 meters.  Just send up a metal can or transhab with the equipment in it.  Have it dock onto an ISS expansion port and start running experiments.  Plus, why do you have to bring massive amounts of material back to Earth?  Most of the equipment can either stay at the station or be ballistically impanted reef material in the Pacific.  The actual samples from the experiments will represent a tiny fraction of the initial mass that can easily come back on a crew return vehicle.

That said, I agree that the lack of sufficient crew makes this all moot.  Also, the lack of any clear cut science objectives for the ISS also make this a wasted effort.

That's one of their stated uses for the tech.  They propose to use it for municipal solid waste, paper pulping, pood and animal waste, waste plastic, waste tires, coal gassification, medical waste processing, hazardous waste processing and petroleum processing.

The great part about this is that there is no uncontrolled venting to the air or water.  Furthermore, the process by default sterilizes the material is works on.  It basically uses high pressure steam which we have lots of experience handling and so represents no tremendous technical issues.

Check out the website, they've got lots of good explanations as well as some detailed technical papers.

Well, the Columbiad folks to seem to think othewise and I agree with them.  There's a big market for small suborbital and orbital payloads.  University research teams that are looking for microexperiments at under $1 million a pop are going to be a constant source of income.

The whole micro/nanosat market seems to have been a bust so let's assume that's not something that can be counted upon.

That leaves fuel/water/etc as a payload.  NASA is already proposing LEO refuelling depots  - the ability to get material to these depots for as cheap as possible would be a wise investment.  As long as you can get more than a few kg per launch, a low cost per kg makes this system a great one for a slow, steady trickle of consumables to orbit. 

The mistake that Dr. Hunter made was to try and convince the gummint to scale up from the SHARP gun to a billion dollar orbital capacity gun.  Had he pushed for an intermediate gun as a proof of concept, there's a good probability that the project would have continued.

These Columbiad folks in Canada (I wonder how many old Richard Bull collaborators are on that team) seem to be working on getting lots of experience with their small guns and slowly working their way up towards more advanced models.  Right now, they're competing with the sounding rocket market.