StrandedonEarth

The earliest rocket launches had no extra margin for debris management, and they didn't know any better. Space is so huge that they thought the odds for collision with a spent stage were vanishingly small, and there was hardly anything else up there to hit. There is also the learning curve, at first they thought a spent stage would stay intact, but they soon discovered that old batteries and residual propellants had a tendency to explode after many hundreds of solar heating cycles, making small hard-to-track debris pieces. Eventually the powers that be wised up and took steps to prevent explosions by venting residuals and safing batteries, and de-orbiting what they could. By that time it was too late; there were hundreds or thousands of debris objects up there, and the odds of collision were reaching the range enjoyed by lotteries: someone was going to "win." As each collision creates more debris, the risk of more collisions keeps rising.

It is cheaper (in the long term) to plan for the long term and build overcapacity from the start, rather than have to upgrade later. The engine production line can probably produce 400 a year running around the clock, but for current demand one shift can supply the need. That's the usual way industry increases production capacity: add another shift on equipment that would otherwise be sitting idle overnight.

Yarrow

Kindly refrain from making disparaging remarks pertaining to or at the sorcerous lithoid.

From Wikipedia, the free encyclopedia Thorium, 90Th General properties Name, symbol thorium, Th Appearance silvery, often with black tarnish Pronunciation /ˈθɔəriəm/ thawr-ee-əm Thorium in the periodic table Ce ↑ Th ↓ (Uqb) actinium ← thorium → protactinium Atomic number (Z) 90 Group, block group n/a, f-block Period period 7 Element category actinide Standard atomic weight (±) (Ar) 232.0377(4)[1] Electron configuration [Rn] 6d2 7s2 per shell 2, 8, 18, 32, 18, 10, 2 Physical properties Phase solid Melting point 2023 K (1750 °C, 3182 °F) Boiling point 5061 K (4788 °C, 8650 °F) Density near r.t. 11.724 g/cm3 Heat of fusion 13.81 kJ/mol Heat of vaporization 514 kJ/mol Molar heat capacity 26.230 J/(mol·K) vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 2633 2907 3248 3683 4259 5055 Atomic properties Oxidation states 4, 3, 2, 1 Electronegativity Pauling scale: 1.3 Ionization energies 1st: 587 kJ/mol 2nd: 1110 kJ/mol 3rd: 1930 kJ/mol Atomic radius empirical: 179.8 pm Covalent radius 206±6 pm Miscellanea Crystal structure face-centered cubic (fcc) Speed of soundthin rod 2490 m/s (at 20 °C) Thermal expansion 11.0 µm/(m·K) (at 25 °C) Thermal conductivity 54.0 W/(m·K) Electrical resistivity 157 nΩ·m (at 0 °C) Magnetic ordering paramagnetic[2] Young's modulus 79 GPa Shear modulus 31 GPa Bulk modulus 54 GPa Poisson ratio 0.27 Mohs hardness 3.0 Vickers hardness 295–685 MPa Brinell hardness 390–1500 MPa CAS Number 7440-29-1 History Naming after Thor, the Norse god of thunder Discovery Jöns Jakob Berzelius(1829) Most stable isotopes of thorium iso NA half-life DM DE(MeV) DP 227Th trace 18.68 d α 6.038 5.978 223Ra 228Th trace 1.9116 y α 5.520 224Ra 229Th trace 7340 y α 5.168 225Ra 230Th trace 75400 y α 4.770 226Ra 231Th trace 25.5 h β− 0.39 231Pa 232Th 100% 1.405×1010 y α 4.083 228Ra 234Th trace 24.1 d β− 0.27 234Pa view talk edit · references Thorium is a chemical element with symbol Th and atomic number 90. A radioactive actinide metal, thorium is one of only two significantly radioactive elements that still occur naturally in large quantities as a primordial element (the other being uranium).[a]It was discovered in 1828 by the Norwegian priest and amateur mineralogist Morten Thrane Esmark[4] and identified by the Swedish chemist Jöns Jacob Berzelius, who named it after Thor, the Norse god of thunder. A thorium atom has 90 protons and therefore 90 electrons, of which four are valence electrons. Thorium metal is silvery andtarnishes black when exposed to air. Thorium is weakly radioactive: all its known isotopes are unstable, with the seven naturally occurring ones (thorium-227, 228, 229, 230, 231, 232, and 234) having half-lives between 25.52 hours and 14.05 billion years. Thorium-232, which has 142 neutrons, is the most stable isotope of thorium and accounts for nearly all natural thorium, with the other five natural isotopes occurring only in traces: it decays very slowly through alpha decay to radium-228, starting a decay chain named the thorium series that ends at lead-208. Thorium is estimated to be about three to four times more abundant thanuranium in the Earth's crust, and is chiefly refined from monazite sands as a by-product of extracting rare earth metals. Thorium was once commonly used as the light source in gas mantles and as an alloying material, but these applications have declined due to concerns about its radioactivity. Thorium is still widely used as an alloying element in TIG welding electrodes (at a rate of 1%-2% mix with tungsten).[5] It remains popular as a material in high-end optics and scientific instrumentation; thorium and uranium are the only significantly radioactive elements with major commercial applications that do not rely on their radioactivity. Thorium is predicted to be able to replace uranium as nuclear fuel in nuclear reactors, but only a few thorium reactors have yet been completed.

6/10 how cute

Around here, wood is plentiful, and so are smoke alarms and fire stations. Wood is also renewable, and wood buildings actually count as a carbon sink. And the most recent building codes call for sprinklers in all multi-family housing. And it's usually the contents that start house fires, anyways. Where red clay is plentiful, so are brick houses. And that reinforced concrete skeleton is new tech to me. It certainly solves the problem of brick structures being vulnerable to earthquakes. But brick and reinforced concrete are carbon-intensive materials. I imagine it is also more expensive, especially if the interior walls are also brick. But it must be great for sound and thermal insulation, although it also increases thermal mass. Those walls will stay warm most of the night.

♫Now look at them yo-yo's that's the way you do it You play the guitar on the MTV That ain't workin' that's the way you do it Money for nothin' and chicks for free♫

Salmon Arm

♪We don't need no educaeshun We don't need no thought control♫

Want a museum piece? No need to bring it home, just use the training mockup in the 'zero-g' pools

I think the term the pros use is "conjunction," as in, "Jupiter is in conjunction with the Moon." I thought the same thing too, that this could cause a panic with people thinking "OMG Jupiter is gonna crash into the Moon!!" Never mind that we'd get the mother of all high tides first, if that was about to happen.

I don't think they'll be moving anything. It'll be one more place they can use, one more prep hangar. Then they can really pop them up one after another.

I created a background intended to be used for "Keep Calm..." style memes. This is the background, for anyone to use: (Edit: For anyone who didn't realize, this is simply a cropped screenshot I took of the monolith near KSC. I wasted a morning finding it, adjusting graphic settings to unbury it, and getting some lighting trucks out there for the perfect shot. Then I added the logo the I found on a Google image search to the top. Enjoy!) I've created two memes for it so far. And it bit more of a Bowie tribute:

Yellowknife

Time for an Ice Age

Geology students get off to a rocky start

Grande Prairie

10 ?"Basic Rulesz!" 20 goto 10

TurboPascal FTW!

Who watches the Munsters?

Let's see, the shortest path through the atmosphere (least aero drag) would be straight up. Horizontal velocity at apogee would be next to nil (aside from that provided by Earth's rotation). So you'd need a kick motor with around 17,500 mph of dV.. If you want some horizontal velocity at apogee, you'd need to fire at an angle, spending way more dV fighting drag, and experiencing a lot more atmospheric heating. Not insurmountable, but by the time you reach apogee you'd still have lost a lot of horizontal velocity. How much horizontal velocity would it be reasonably possible to have at apogee? Now here's a thought for a very low ISP kick motor: there's going to be an awful lot of heating to get an appreciable hV at apogee, right? Have a significant part of the projectile be made of water sealed in a pressure vessel. At apogee open a valve to an exhaust port, and use the steam for thrust. The water would be doing double duty! Of course, I doubt that would be enough...

How do you pin someone to the mat in zero-g anyways? I think it would have to be more like the high-school sport of "pin-them-in-the-locker"