christok

Slow depressurisation resulted in cardiac arrest within approximately 30 seconds during Soyuz 11.

An interesting proposal but I don't think so for two reasons. Firstly, the lighter elements escape preferentially and hydrogen is in very short supply at Venus. The planet has e.g. only ~30 ppm H2O in the higher parts of the atmosphere where it shows up in absorption spectra. (Water is probably less common low down, since it's less dense than CO2.) The crust also seems to be bone dry. Secondly, you must be at an altitude where aerodynamic effects are significant for the meteors to have the desired effect. So if a random heated molecule wants to escape, it must first go up through a lot of atmosphere interacting with and losing heat to other molecules along the way. It should cause some loss of gas, but nothing significant compared to what solar radiation and solar wind already does. The gas released by the meteor might even be more for the right kind of meteor (I haven't done any calculations).

Monosilane has been seriously considered for Mars + Venus.

Adding water would worsen rather than improve the greenhouse problem. I have a more fun suggestion. Venus lacks a magnetic field due to its entire core being in a single phase (unlike the solid inner and molten outer core of Earth), probably solid because it has already frozen. It also has too much atmosphere. And it lacks a large moon, which may or may not be needed. Earth doesn't have these problems and is a little larger to boot, on account of a "giant impact" with a Mars-sized body in the distant past. So the plan is, we go looking for some convienently Mars-sized body lying around the solar system...

Didn't you just describe a regular brain?

Here you go: http://conceptualmath.org/challenge/bases.html And just because it's Knuth: https://dl.acm.org/citation.cfm?id=367233

Here's Dr Bruce Betts' Online College introductory astronomy class archived at the Planetary Society: http://www.planetary.org/multimedia/video/bettsclass/ (I haven't watched it yet.)

Thermal conductivity isn't all bad. It's good if at least the leading edge of the heat shield conducts heat somewhat, which creates a heat-sink from the point of view of any hotspots. And letting the heat be conducted deeper into the heatshield creates a better sink (as long as you don't let the sensitive parts of the spacecraft get too hot, of course). Heat shields get rid of energy in three ways. Ablation, radiation and heat sinking. The latter doesn't directly get rid of the energy, of course, but gives radiation more time to do its work. Copper is actually discussed as an almost doable shielding material in the book I quoted, in the form of a big heat sink and radiator. It isn't practically viable by any means but an interesting concept nonetheless. lajoswinkler, interesting info on the Apollo shield. I did not know about the silica content. You are correct about the refractory materials used in heat shields sublimating. The table I looked at had the sublimation temperatures listed for materials which are below the triple point at 1 atmosphere under the heading "melting point". I didn't notice, so take your pick if you want to blame me or the author .

I don't have any data on the Soyuz specifically but I can almost guarantee that it must be graphite--the usual suspect. Graphite requires 28700 Btu/lb to vapourise, compared to 13400 Btu/lb for beryllium oxide*, 3865 Btu/lb for titanium and 1870 Btu/lb for tungsten. Given the very high energies that need to be dissapated (e.g. 13500 Btu/lb for a velocity of 26000 ft/s, although the vast majority of that goes to heating the atmosphere instead of the spacecraft) it should be clear why. The melting point of graphite is also above that of any of the materials listed. I've copied the numbers above from W.L. Hankey's Re-entry aerodynamics, 1988. AIAA. p. 4. (Sorry but I'm too lazy to convert to SI.) * A rather good heat shield but probably a bad choice due to the toxicity of Be. Not to mention the superiority of graphite and the cost.

Electrons in atoms pass through the nucleus quite often. It's at those times when electron capture (one of several forms of beta decay) can occur. Edit: Just to be pedantic, I should say "often" refers to times when it has a definite, known location. What it's doing at other times can of course not be known.

QED models electromagnetism and can hardly tell us much about a gravitational problem but I agree that it plays a role. The scenario probably requires a working theory of quantum gravity for accurate modeling. (I'm going to have to add a disclaimer here: I'm still slowly trying to learn QM and GR so take what I say with a pinch of salt.) I agree that the electron should fall in sooner or later. We need to figure out whether the electron will be able to lose energy as photons--I have a hunch it is so--in which case it will rapidly end up in the black hole. Problem is, QED must tell us whether photons are emitted but doesn't play nice with gravity. Back to the original question, I'm surprised no-one has mentioned Mach's Principle. The question of whether the universe as a whole is rotating is in fact very important in General Relativity: http://en.wikipedia.org/wiki/Mach%27s_principle. The question of preferred reference frames is often interesting.

It's completely possible to run jet engines in an atmosphere without a strong oxidising agent--you just need to pick a stronger reducing agent. Monosilane has been proposed for jet engines on Mars and Venus since it can burn in CO2. It has also been proposed as a rocket fuel for lunar ISRO, since silica and water should be available. The stuff is quite nasty, as you can imagine.

I don't have many books on this topic and I'm very far from finished with them but I suppose I can recommend two. If you want a book on just orbital mechanics of spacecraft, I have and enjoy Orbit & constellation design & management by Wertz. It's very comprehensive but perhaps a little lighter on complicated interplanetary maneuvers such as multiple gravity assist trajectories. It's a somewhat specialised topic and you'd want a dedicated book if you want to get your hands dirty. The information on interstellar trajectories is fairly basic but there is a decent list of references. (In the unlikely event that you actually do want to study interstellar trajectories, you can start with The starflight handbook: A pioneer's guide to interstellar travel by Mallove & Matloff. Even better, the journal of the British Interplanetary Society has for a long time been a major publication for papers on this topic. Robert Forward was one of the early pioneers in this field so you could always just search for his work.) If you'd like more general information on other aspects of spaceflight as well, Space mission engineering: The new SMAD or the older versions (Space mission analysis and design, AKA SMAD), edited by Wertz, Everett & Puschell is very insightful. It has a chapter on orbital mechanics but is very light on interplanetary flight. Search Amazon and astrobooks.com and borrow what you think you need from a library (inter-library loan if necessary). If you then decide you'd like a copy you have peace of mind that it's money well spent.

The giant does not have to be more massive than the neutron star if it isn't required to go supernova. Any star can enter the giant phase if it is sufficiently massive to ignite helium fusion--about half a solar mass is sufficient. However, such a small star has a very long life. The ideal mass of a star is the so-called "Fundamental Stellar Mass" (denoted M-subscript-*), which balances various physical laws to produce a star which is massive enough to achieve and maintain fusion reliably and small enough to not blow itself up early on. It's around 1.85 solar masses--the sun's proximity to the Fundamental Stellar Mass is perhaps a part of why we humans can exist. For a simple boom you'd want something bigger than the Fundamental Stellar Mass. As for what to do, it is very difficult to pick a stellar event which doesn't completely destroy your ship. (That 10^42J/year I spoke about? That's a hundred million suns right next to you.) My best suggestion would be a regular, non-super nova in a trinary star system. The largest has already exploded (stripping some mass from the others in the process) to create your neutron star. The other two are a white dwarf slightly less than half a solar mass and a slightly more massive red giant. The dwarf and giant are orbiting one another and spiraling together--the dense white dwarf is already stealing mass from the giant. These two together orbit the neutron star at a considerable distance. The planet is in an elliptical orbit around the neutron star. You can excuse its presence so close to a supernova remnant because it was originally orbiting one of the other stars. When the white dwarf has taken enough mass from the giant, a helium flash occurs. (See the wiki page on helium flash for a brief introduction.) If your gas giant is behind the neutron star at this time, you might be able to hand-wave the physics sufficiently to get within a few orders of magnitude of survival. Remember that mass will be lost and temperatures raised in the nova. You could land on an icy moon and drown. A gas giant should have high metallicity because the original supernova would have reduced its mass, especially hydrogen and helium. It's okay if you make the physics only approximately correct and the circumstances unlikely. Otherwise it's just "everyone dies".

Perhaps or perhaps not. I do think it's the closest thing to the original post which gets serious press. I honestly haven't punched the numbers but it remains a cool idea if someone can figure out a way to use it. Even if it isn't cheaper it would reduce the stresses of launch and reentry, which seriously compromise the validity of many biological experiments.

I'd suggest making your terrestial planet the moon of a gas giant instead. There are many reasons: - One is that the gas giant could have somewhat shielded the moon against the formation of the neutron star (through its magnetic field and by just being in-between for the worst part). This could give you greater flexibility in the kind of life which could be present after a reasonably short time but don't think it makes the damage small in any way. - Another is that you can use the far side of the gas giant as the "safe" zone (I'm being optimistic here) instead of just saying the ship got blown out far enough to survive. (Have your ship rapidly approaching the safer side when the star starts to go boom.) - The creation of severe fluctuations and radiation bands in the magnetic field of the gas giant during the explosion makes the reasoning behind your electrical failures more obvious. - Multi-body dynamics makes it generally easier to throw things around. The interaction between the moon, the gas giant, other moons, etc. could be what sends your ship towards the black hole. In particular, I think the expanding atmosphere of the gas giant (due to heat from the supernova) could create an unexpected aerobrake. Use this to send your crew towards a moon encounter they didn't see coming and gravity-asist them out of the gas giant SOI and into the black hole. I'm a little iffy on that last point since I'm not that clear on the details of gas giant atmosphere but hey, it's probably better than what you get in most sci-fi. I've been severely underplaying the damage from a supernova. Might I suggest anything smaller? Besides the obvious explosion, debris from a supernova is so hot it puts out around 10^42J of optical energy over the year following the explosion. Your supernova survivor is probably getting fried no matter which direction he goes. If you want to stick with a supernova the best I can think of is parking the lifeboat in a deep canyon on a tidally locked moon, facing the planet, and using some sort of hybernation chamber for a number of years. It might not work if the atmosphere swells enough to deorbit tidally locked moons or if drag from the supernova debris does the same. Keep in mind that your planet must be quite far from the neutron star, since anything close in would have been devoured during the red giant phase. Also, stars lose a lot of mass late in life and planets drift a little out. In particular, the maximum possible mass of a neutron star is probably less than three solar masses while the minimum mass of a star that goes supernova (and thus to a neutron star) is around 8 solar masses and up. These numbers are actually a lot more debatable than what Discovery Channel et al. will lead you to believe. One terminology issue: A giant star on the verge of core collapse is not "main-sequence". The latter refers to a star in the hydrogen-buring phase. It swells up around the time it starts to burn heavier elements, if at all. In the case of one that goes supernova, it will have already burnt elements up to about silicon in the core. The final, silicon-burning phase will last days and the core collapse is on the order of a second. Keep your secondary star a giant no matter what you change. Its habitable zone is farther out (and larger) allowing you to have more plausible lifeforms. Also, what Wesreidau said.

I think I stated that poorly. I don't refer to a balloon-launched rocket but to a spacecraft that is a balloon. It doesn't fall because of bouyancy, allowing you to accelerate at any pace as long as thrust > drag.

The idea of getting to orbit with a balloon/airship isn't extremely far fetched. While it doesn't take you to orbital velocity in itself and there is also still substantial aerodynamic drag at any altitude an airship can reach, it does have the advantage of letting you go to orbital velocity with low thrust (since you're less inclined to fall). The JP Aersopace guys have been talking a good fight for some time and I dearly wish they could get their concept off the ground. For your amusement, almost everything in the current thread was discussed previously in the "Airships" thread (May 2013).