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Spacenut, what's up with all these block quotes with no comments you keep posting?
The question is why use wheels in 2020? Wheels can get stuck on obstacles that legs can step over, and I hear there is work on legged robots.
C'mon Tom, you know the answer to that. Legs have more moving parts and are therefore more prone to failure.
Quaoar: to answer your earlier question to me, I only had in mind two broad categories of gas core thermal engines. Those are open cycle and closed cycle. I'm not familiar at all with something called "saltwater" somewhere just above. I've been outside the industry for 2 decades now (one of those industry "consolidations" got me, where they fire half the workers, keep all the upper level managers, and live off the backlog for about 3 years until they can bail-out with their "golden parachutes"), making it very hard to stay abreast of things.
Nuclear saltwater is something Zubrin came up with. The gist is this: You dissolve a fissile salt in water, and put it in thin tubes of a neutron moderator. For thrust, you pump this saltwater into the reaction chamber, where it becomes critical. The saltwater becomes plasma and exits the reaction chamber. The jury is still out on whether one could build an engine capable of withstanding the reaction.
GW Johnson wrote:There's at least two wildly-different versions of gas core, too.
GW
Which are?
I can think of three off the top of my head. Nuclear Saltwater, Nuclear Lightbulb, and Coaxial.
Oil platforms require a bottom to rest upon and be anchored too. If you go far enough offshore, past the edge of the continental shelf, the bottom is unreachable at over 2 miles down. In deep water, a self-positioning barge is the only answer.
A semi-submersible oil platform is what I was referring to.
Thanks for explaining that.
One wonders if any consideration has ever been given to building a permanent (stable and bigger) platform out to sea on the model of oil platforms.
Oil platforms are tremendously expensive; even a cheap ancient one is $77 million. Still, they're probably considering it.
That sort of sounds like a hydraulic leak, without enough reserve to make up for it. Common enough failure mode. Edit: the hydraulic press in my shop recently blew a rod seal. It loses lots of hydraulic fluid unless I park it in just the right position.
The grid fin hydraulics are an open system. Pressurized RP-1 powers the grid fins, and drains into the main RP-1 tank after use. No compressor.
Also putting them in space eliminates the human element, which is uncertain. When you want to deter an enemy, you want certainty. You don't want the enemy thinking, maybe the other guy won't respond if I do this.
Instead, they'll be wondering when one of those nukes will malfunction and kill tens of thousands anyway. Your blind faith in the reliability of technology makes me wonder if you've ever worked on a machine, electronic or otherwise, in your entire life. Every device humans create breaks, often in unexpected ways.
Any reason (other than "Oh my Budda, nukes!") that we couldn't make a CO2 NTR? Something that combines aspects of Project Pluto and NERVA.
You're ignoring my point. You want to put nukes on a dead-man's switch. If one of them malfunctions, tens of thousands of people die, and a war probably starts. Do you think "Oops, it wasn't supposed to do that" will mollify anyone?
I'll anticipate one objection, what if a nuke suffers a communications failure? in that case the nuke detects no signals from Earth, in which case it doesn't do anything, but if it detects radio signals from Earth but not signals in the proper code that tell it to do nothing, then it homes in on its preprogrammed target.
So you acknowledge the problem with dead-man's switches on nukes, yet you advocate it anyway? Really?
The stabilizing factor of Mutually-Assured Destruction is derived from the second-strike capability of ballistic missile submarines. Since the other side does not know where the submarines are, they cannot strike to destroy the launchers. Since they can't destroy the launchers, they can't prevent a devastating counterattack. Since they can't prevent a counterattack, there is no need for the defender to strike first.
If the devices are in space, they can be tracked and targeted.
Excellent work, Antius. Up till now, I was under the impression that we had zero data on mammalian response to Martian gravity. Or anything between 1 and zero gee, for that matter.
Granite is both attractive and durable. If it's available, it's an excellent material.
Congratulations! What sort of readings will you be taking in the next few weeks?
I don't think there will be much commerce between Mars and Earth. Naturally, there will be information products, but they aren't likely to be much different from what we have here. The best sources of wealth are small bodies like Luna and NEOs. Places with resources(propellant, fissionables, structural materials, etc), very low gravity, and no atmosphere. I think we'll see a lot of commerce between small bodies and whatever places we colonize, but little between large bodies.
1. Procreation will require some extended replication of 1G
What do you base this on? We have no data between zero and one gee.
Well, getting it close to the sun is much the same in terms of deltaV as actually hitting it.
I'm sure the Martians will come up with all sorts of creative death rituals. Recycling the body always seemed like a good one to me but if course there are others. launching it on a trajectory to burn up in the Martian atmosphere is good. Less kosher, so to speak, would be to feed it to livestock, or even perhaps close friends and family. You are disgusted,I presume, but it's certainly not impossible to imagine that there could be symbolic significance.
Then again, that is probably unsanitary for the same reason we don't eat sick animals.
Cannibalism is a bad idea for disease reasons, not just the squick factor, as you said. Watching pigs eat your son's body can't be good for morale either. Burying the body in a greenhouse or composter seems like the best option. If you bury the body in the greenhouse, you can still have a traditional funeral, you'd just need to use a biodegradable container of some sort. Dumping dirt on your dead son's uncovered face would, again, probably be bad for morale.
The main issue with straight burial is you still have bones floating around in the dirt. I don't know that grinding the body up before burial would really be acceptable to their kin.
Void, I don't think the outcome is going to be favorable. After this latest debacle in Washington, it's clear the ear-mouths have won, and we are doomed.
http://freebeacon.com/china-testing-new-space-weapons/
China last week conducted a test of a maneuvering satellite that captured another satellite in space during what Pentagon officials say was a significant step forward for Beijing’s space warfare program.
The satellite capture took place last week and involved one of three small satellites fitted with a mechanical arm that were launched July 20 as part of a covert anti-satellite weapons development program, said U.S. officials familiar with reports of the test.
...
Thought this seemed interesting and useful.
Decimator:
Didn't you and I and Josh pal around at the recent convention?
GW
Yep!
No idea what a code tag is. I'll try the periods.
Thanx,
GW
Hit quote on my previous post and look what I did. I wrapped the table in bbcode tags.
You can use code tags like so:
Ore color formula iron content where found
Hematite red Fe2O3 70% near Lake Superior
Magnetite black Fe3O4 72.4% NY, AL, Sweden
Siderite brown FeCO3 48.3% NY, OH, Germany, UK
Limonite brown Fe2O3xH2O 60-65% Eastern US, TX, MO, CO, FranceThis sounds like "It hasn't already been done, so therefore cannot be done." We would never have discovered fire with that attitude. What happened to NASA's can-do attitude?
No, it sounds like "The laws of physics as we know them prohibit it." A can-do attitude isn't going to overturn speed of light limits any more than a can-do attitude is going to make rocks start falling up!
You have to send information via a classical channel to use quantum entanglement to transfer information. I'd like to see some papers claiming otherwise if you disagree.
I'm considering going this year, but finding it somewhat difficult to justify the cost to myself.