Bill Phil
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Posts posted by Bill Phil
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Yeah, but that's kinda like starting a sentence with "If we had warp drive...". We don't have rocket engines that reliable, and barring miracle breakthroughs in nanotech, won't have them in the near future. Reliable enough to carry passengers without an escape system is four or five orders of magnitude beyond the most reliable engines ever built. That'll take tech like building an engine atom-by-atom out of synthetic diamond.
We've been building ocean-going ships for thousands of years and those still aren't reliable enough that we skip the escape system.
The shuttle didn't have a LES system. It only had a fatal launch failure ONCE, out of 135 flights. That's reliable, and that was 70s tech. Sure it was improved, but what if we built it with modern tech? It would be EVEN more reliable.
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ah, but Mars takes less Dv to get into orbit.Mars does provide space, and most importantly, water. You could cake its surface and get an atmosphere that retains heat. It's less hostile for human habitation than the Moon. But I most definitely agree with you that the Moon provides an optimal staging center for space travel.And the Moon takes less as well, but Deimos has practically no gravity, so mining it and Phibos is preferable.
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You can orbit a black hole just fine. It's just another gravity well, so orbiting it works the same as orbiting a planet or a star.
In the sense that you can orbit. The velocities would be HUGE though.
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Well, they could add 1.875 meter parts. Fuel tanks, engines, a 2-kerbal pod, decouplers, etc.
So then the mk3 would have a use. Then mk4 could be 2.5 meter.
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We're getting into semantics a bit, but outside of SF, that is how you "use" antimatter in science. Annihilating stuff just isn't that useful on its own; the correlations and implications are where the utility comes from.
As a sidenote:
Pretty much all medical imaging techniques (and a lot of other things in science) work like this. When you want to measure something that you can't observe directly, you find something that you can observe that has a reliable correlation with the thing you're actually interested in.
Brainscanning via fMRI measures disturbances in a magnetic field, that we infer into a measurement of blood oxygenation, which we further infer into an estimation of neuronal activity. EEGs measure electrical currents, MEGs measure the magnetic effect of those currents. Immunohistochemical neuroscience uses custom antibodies to visualise the occurrence of proteins that are associated with neuronal activity or injury, while high-pressure liquid chromatography (a standard technique for detecting changes in neurotransmitter levels) measures electrical resistance in the output of a pump and correlates the time of output with molecular weights. In none of these cases are you actually examining the neurons directly.
You can stop with the educating, because I know that's how it's done.
Yeah, it is semantics. But I don't understand what your original point was. I was saying it was beyond us, and I was refering to its usefulness as a resource, such as in the ISV Venturestar.
What are you saying? It's already used? Well, that's technically correct. It is used, but not in the way I was talking about. Which is as a catalyst or a direct energy source.
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I used to work with PET scanners professionally; ex-neuroscientist. If you're looking for a citation, you're probably best off starting with Wiki (http://en.wikipedia.org/wiki/Positron_emission_tomography) and then drilling down into the references at the bottom of the article.
The basic way that a PET scan works is that you inject the patient with a mildly radioactive substance that is chemically attracted to the biological structure that you're interested in tracking (for example, FDG-PET brainscans use a form of radioactive glucose that is enthusiastically absorbed by active neurons). As the radiation decays, it produces positrons, which in turn produce bursts of gamma radiation when they collide with normal matter. The scanner can identify the source location of the gamma, which allows the measurement of where in the body the positron annihilation is occurring.
Making antimatter is easy; all you need is some radioactive decay. Pretty much every radiologically active thing is constantly surrounded by a transient cloud of the stuff. The hard part is in preventing it from immediately contacting normal matter and mutually annihilating.
That's not using antimatter, it's taking advantage of it, sure. But it's not USING antimatter, the antimatter is a byproduct and allows the detection of where the problem is indirectly.
It's taking advantage of the fact that antimatter does specific things, which is just a useful property of antimatter. WE can only produce a few particles of the stuff, and can only contain it for a short time.
Positrons from decay are surrounded by matter, so it can't be contained because of that.
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Ahh...no. Antimatter is routinely used in common medical technology. A PET scan (Positron Emission Tomography) is an antimatter device; positrons are antimatter electrons.
Antimatter isn't magic, any more than normal matter is.
Any good source?
I'm not saying magic, it's just a very volatile substance that we can't make much of.
Plus, PETs only TRACK positrons. They don't shoot a super-beam or anything resembling a beam of particles.
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That's to a much lower inclination than the ISS, and an instated altitude; it doesn't mean they can actually put 13 tons to ISS. Particularly as Orion would be unable to actually intercept the station with no SM.
Oh I know, however, it's not pushing it, and the ISS orbit is still low, and takes a few hundred m/s to rendezvous at most, probably less, including the initial boost from your lower orbit to the target.
Maybe a smaller propulsion stage rather than a full SM.
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You can't just chop off the service module and even if you could the capsule would be pushing it too far for an F9. Also due to the lack of the Orion production line it would probably be more expensive.
Orion is designed to operate without the SM.
The F9 can orbit almost 13 tons, Orion capsule is almost 10 tons. Hardly pushing it.
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That scale of incoming mass in the form of food would require the freighters also haul out gigatons of "biowaste" (in the Elite: Dangerous parlance).
They did have to so that. The reliance on that as well as food being shipped in contributed to the fall of the Galactic Empire.
Oh, and Terminus. It has little metals, if any at all.
Arth in Starflight is interesting, as well as the Crystal Planet.
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Soyuz costs $70 million a seat, so $210 million per crew rotation. DIVH alone costs $435 million.
However, DIVH could be used in an EOR scenario, if they go that route. F9 costs around $60 million, and plus you don't have to transport the 'nauts to Russia, so if you put an Orion on an F9, without a service module, you could get a better price. Although, a CST-100 or Dragon would be better.
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And until then Soyuz works just fine. It's throwing a lot of money away for no good reason.
Soyuz is expensive as well. It costs a large amount of money per seat. And the Russians will pull out of the ISS program in 2020.
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Because that'd be considerably more expensive than just using one of the CCDEV vehicles.
Dragon won't fly crew to the ISS for a while.
I was saying to orbit a full Orion. An F9 could be used for just the capsule.
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I like Star Trek, but the Enterprise is not practical AT ALL. Why not an international Nautilus-X?
It took almost 15 years to build the ISS. And it's just a space station and has only enough Dv to maintain its orbit and maneuver the station.
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It seems like the Delta IV Heavy could orbit the full Orion. Why can't we orbit it with a crew if all checks are good? Then we could have Dragon for supplies, and Orion for crew, to the ISS of course. Because as far as I know, the first crewed Orion is EM-2's vehicle.
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Nobody's bothered, as far as I can tell. ULA have never considered a rocket with more than 3 cores.
Huh. Well, that's a shame.
The concept is interesting, it's simpler than cross-feed, and it means you can use the same core module for the boosters. Although Angara has more flexibility, from 3.8 tons to 24.5 tons. If they use Angara A3, they could have a launch vehicle comparable to a Delta IV. IMO they should definitely develop the A3.
All-in-all, it's a good direction for the RSA to take.
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You'd need both a completely new pad and an extensive redesign of the CBC.
Obviously. However, it is possible, and how much payload could it deliver? Any estimates on that?
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@Bill Phil: Honestly, Angara A5 never was considered as Mars or even Moon launcher. It is replacement for Proton and it's main mission is to launch military and civilian satellites to GEO. There was proposition for heavier version: Angara A7 with ~35 ton to LEO, but it wasn't received fund for development mainly because it requires larger core stage (4.1 m - Proton size).
I never said to use Angara, I was saying that it's more efficient to use a modular rocket system similar to Angara, rather than a super-heavy launch vehicle like SLS. Angara was an example.
Hmm, what if we strapped a bunch more CBCs than the typical two around a Delta IV? Could we get more payload at all?
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And Trantor was just for Administration. A whole planet, just for administration. Really strange.
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Except then you hit volume and timing issues. An EDS for, say, a Mars mission simply will not fit in the A5 fairing, and will be subject to prop boiloff between flights. Given the number of Angara pads (1) and the payload capability of A1, you'd have a struggle just to pump it in faster than it's coming out.
It would load a small amount if consumables into an already in orbit vehicle. Which means we'll need to get a lot of them. Of course we could just use Antares. That'd be preferable.
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Of course the whole mission is crewed. Are they supposed to knock together another of whatever 20-odd ton component failed to launch in the few months the rest of the contraption would have in a stable orbit? This is one of the major reasons nobody uses EOR.
Is it? Depends on the mission. If you use a small (say, Angara A1) to launch the consumables, and then you use one 10 ton dry-mass as a target, it's a lot less "risky".
If one, ONE, SLS fails, with a crew especially, the whole program, everything, will be delayed for a few years, if not outright canceled. But if ONE unmanned( the heavy versions will always be unmanned) launch fails, the whole program isn't necessarily screwed, especially if the rockets ( and thus the components for the LEO spacecraft) are much easier to replace. It's very difficult to mass produce HUGE rockets such as SLS.
Besides, who builds something in LEO and doesn't expect a launch failure? They would put thrusters on it to maintain orbit, it shouldn't be that expensive in terms of money or Delta-v to put small vernier thrusters on it to maintain orbit, considering the Dv to deorbit is very small. And thus logic dictates that maintains orbit should be easier than deorbiting.
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Roobie- GP2, purple and red clouds, Saturn analog, 4000 km radius, 3 major moons, 1 Dres-esque moon(size and gravity) and a gilly-esque moon, asteroids spawn occasionally
Dimund- GP3, light orange and hints of yellow, 1400 km radius, Neptune/Uranus analog, 1 major moon, 1 Minmus-esque moon, 2 gilly-esque moons, and an asteroid spawner
Chraon- ice dwarf, brown-ish with dark blue, Dres-sized, Pluto analog, 1 moon of mass similar to Minmus,
Kyper Belt- asteroid belt beyond Chraon with a more ice-like texture, larger 'roids are less common, more asteroids total than in NKOs, basically like the Kuiper Belt
Well that's my two cents...
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Besides, we're getting off topic..
On topic: Congrats Angara team! Someone's making Progress in space! ( get it, Progress, ah. Ever mind)
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Well, problem is that you'll be making a bigger second stage if you're using powered landings.
Combining the second stage and the capsule? A Reuseable spacecraft concept? (Updated)
in Science & Spaceflight
Posted
Well, that's primarily due to the fact that the US hasn't had much of a budget for spaceflight, and so engine development had to be sacrificed.
There's always room for improvement.