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Comment: Re:Citation needed (Score 1) 167

by cmowire (#34058284) Attached to: Launch Command Preserved In Power Failure, But Nuclear Designs Still Risky

Yeah, I'm under-impressed with the site's rigorousness as well. Everything the author talks about is something that's been talked about endlessly in the public literature. With the claims made, I kept thinking there was at least a rumor-mongering hint about something new and different.

Comment: Re:It's about time (Score 2, Interesting) 140

by cmowire (#33955554) Attached to: International Effort Brings an Open Standard For Docking In Space

It was.

This is fairly similar to the APAS docking adapter they created for the Apollo-Soyuz test program in the 70s.

Now... why the ISS doesn't use APAS for all links and why the ISPRs (international standard payload racks) that everything in the US section is contained within won't fit inside an APAS docking tunnel... well... heh heh.

Comment: Re:Shiny! (Score 1) 248

by cmowire (#33156920) Attached to: SpaceX Unveils Heavy-Lift Rocket Designs

Well, notice that there are two Falcon 9 cores listed. There's the one with a single Merlin 2.

Given the systems approach that SpaceX has, I suspect that the Falcon X Heavy is slotted the same as the Falcon 9 Heavy -- there if you need it to attract NASA or some customer before the Falcon XX is ready. I'm assuming that the Falcon X's core diameter is sized around some constraint (factory size, transportation, etc) and the Falcon XX is designed under the assumption that funding to exceed said constraint was provided.

I think it's all about options and incremental development. They don't have to qualify the heavy configs until they need them and that's the hard part.

Comment: Re:Proven delivery system (Score 1) 230

by cmowire (#32921748) Attached to: Senate Bill Adds Shuttle Flight, New Shuttle-Derived Vehicle

It turns out that in business school classes on running defense contractors teach a fairly simple concept:

If your project isn't far enough along to survive cancellation when the power shifts in the white house, you fucked up.

Thus, NASA's problem isn't changing political whims, it's that the Constellation program was so far behind, overbudget, and mismanaged in 2009 that it got canned by the incoming administration.

Comment: Re:Economy of Scale (Score 3, Interesting) 283

by cmowire (#31001164) Attached to: The Upside of the NASA Budget

Actually, the ISS is bigger than Skylab at this point.

The problem with the shuttle building the ISS is that it's really the worst of both worlds. You spend billions of dollars a year on the shuttle and build the American part of the ISS on that set of constraints and then wonder why it cost so much. Whereas, If you were to have lofted the American part of the ISS on commercially available boosters, even after the additional hardware to make each module contain a tug, you'd have built it for a lot less.

Especially if you also consider that most everything gets cheaper in bulk and, if you were to place a guaranteed order for a hundred medium lift boosters, you'd get them at a much more reasonable price than the equivalent upmass in ten heavy lift boosters. Especially given that medium lift boosters are the right size for commercial missions and heavy lift boosters are not yet.

The problem is the sunk costs fallacy. NASA had the design and hardware for Freedom and modified it instead of taking a giant step back when they had a chance. The shuttle was there and it worked, even though we might have done much better to have sent it to the museums after the first time we lost one.

Comment: Re:Taking notes from the bicycle industry (Score 1) 67

by cmowire (#30909118) Attached to: NASA Tests All-Composite Prototype Crew Module

Um, I think you are ascribing far too much engineering expertise to the folks who work in the bike industry. The bike industry spends a lot of money on marketing and throws a few pennies at engineering. And the cyclists of the world eat it up.

There's something to be said for not knowing that what you are doing is something that engineering textbooks teach you not to do. This can lead to great things. But this also leads to carbon fiber parts that fail in all sorts of catastrophic ways. Or tires with colored bits of tread that gets squirley in the rain. Or brake designs that every other brake-using industry (cars, airplanes, etc) rejected as unsafe being sold as the next great thing.

Personally, I'm glad that the transfer of knowledge goes only one way, albeit poorly. I would not want to fly cross-country on an airplane with a Shimano HollowTech Carbon Fiber wing spar that's super light and has the occasional habit of snapping mid-flight leaving the aircraft wingless. You can get away with all sorts of design sins with bikes because most people who can afford high-end carbon fiber bikes don't actually ride them very often and, if they do, gingerly descend only on smooth roads at 15 mph.

Comment: Re:Much as I'd love to make a great pun about uran (Score 1) 347

by cmowire (#30901076) Attached to: Uranus and Neptune May Have "Oceans of Diamonds"

The shuttle is the way it is because nuclear launch systems are really messy on a populated planet.

A wide variety of nuclear propulsion systems are available and have even been vaguely tested on Earth. Like Project Pluto's nuclear ramjet. Nobody to piss off next door on any of the gas giants.

Comment: Much as I'd love to make a great pun about uranus. (Score 5, Interesting) 347

by cmowire (#30899584) Attached to: Uranus and Neptune May Have "Oceans of Diamonds"

The possibilities of exploring the outer "ice giants" is massive. I think, at least. I may not even make the pun because I think the idea of exploring them is so interesting.

Submarines are designed to handle a test depth of maybe 1600 ft which means maybe 50 bar of pressure. At that pressure, the atmosphere of Uranus is a little below freezing. The gravity is less than Earth. I suspect that with correct ballasting you could make a metal sphere float in the atmosphere for quite some time by keeping the insides pressurized to a convenient atmospheric pressure. So sticking around for a while isn't hard.

I can't find any good information on the radiation environment there and if you could put humans in the little bubble circling Uranus.. um.. yeah, I lied above.

Comment: Re:Three points (Score 2, Interesting) 234

by cmowire (#30106940) Attached to: NIF Aims For the Ultimate Green Energy Source

Fusion that does not produce neutrons.

Eg, D + He 3 -> He 4 + p vs. D + T -> He 4 + n. The first, deuterium and helium-3 produces helium 4 and a proton. No neutrons. But deuterium and tritium produces helium 4 and a neutron.

The problem is, not perfect. With the deuterium hanging around in a reactor, you'd get some degree of neutron-producing reactions anyway.

Comment: Re:Three points (Score 3, Interesting) 234

by cmowire (#30106904) Attached to: NIF Aims For the Ultimate Green Energy Source

You do realize that iron would become brittle as steel from the neutron flux if you built your reactor vessel out of it, right? It's a vague problem with fission reactors that required some procedural adjustments once neutron embrittlement was better understood, but with orders of magnitude greater neutron flux...

Nor can you rely on a isotope chart of a single element to predict what's going to occur in a high neutron flux environment.

For example, Fe 58 is stable. Capture a neutron it becomes Fe 59, with a 44 day halflife to Co 59. If Co 59 captures a neutron, it becomes Co 60, which is a long-lived radioisotope.

So I guess you do get a reactor vessel with a certain amount of cobalt isotopes, no?

I wouldn't classify this as an "unsolvable problem" but you can't magically wave your hands and make them go away.

For all the "oh my god radioactivity" crap that's going around, the simple fact of the matter is that you can access the core of a fission reactor while it's online whereas you cannot access the core of a fusion reactor while it's online.

Assembly language experience is [important] for the maturity and understanding of how computers work that it provides. -- D. Gries

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