Starman4308

Well, if every single human being on Earth did that, there might actually be a chance with enough lead time to give the solar sails time to work. Sadly, not every man, woman, and child on Earth possesses a Falcon 9. In fact, ownership of Falcon 9s is rather selective, to the point at which this plan is simply infeasible.

A, Minmus is easier for rocket design than the Mun. You need just a little bit more fuel to get there, orbital insertion and landing costs much less dV, and return to Kerbin is about the same. The only challenges are the inclination (try to launch when Minmus's orbit crosses over KSC, so you can launch directly into the right plane) and the size of the target (requiring more fiddling with your maneuver node). It also suggests inefficiency in rocket design to me, because it shouldn't take 200,000 funds to make a Mun rocket. This should get you there and back, and it's not even a fully optimized design. I strongly suggest Kerbal Engineer to get you delta-V and TWR values, and staring at the dV chart from the Wiki page on Kerbin. That plan utterly neglects the Oberth effect. The faster you're going when you make a burn, the more kinetic energy you get (KE = 1/2 *m*v^2), and it takes kinetic energy to escape a gravity well and continue on with some velocity thereafter. You want to make your interplanetary transfers in Kerbin orbit, because in Kerbin orbit, you get 2.2 km/s just from hanging around in LKO. One thing you could do if you were concerned about fuel on a specific craft would be to transfer to Minmus orbit, refuel there, and then drop back down to an elliptic Kerbin orbit, but the timing on that is extremely finicky, and you burn more fuel overall. Spamming part test and Kerbal rescue contracts, mostly. Atmospheric and suborbital tests are lovely: you can easily get up to the target with a single stage going straight up, test whatever you wanted, pop chutes, and get 98-100% recovery on parts.

I love it! Is it at all possible to include a small launch clamp, so you can launch these rockets at an angle, much like real-world sounding rockets (which didn't have a godlike human giving them a 5 degree tilt in flight)?

Apollo was pretty close to 100% utilization of the limiting resources, namely being aerospace engineers. There were quite a few people who got aerospace engineering degrees in the early 1960s, and found themselves without a job in the 1970s. Had we gone to something silly like 100% taxes, we still could not have done it much faster, because we were already going full-speed through the primary bottlenecks. As I mention below: WWII is a terrible example. WWII was extremely unique, a situation where the state of the art was still, albeit just barely, in the realm of mass-manufacture by non-specialty personnel. There would be a huge number of bottlenecks for an Orion project, all of which require skilled personnel who you simply cannot train that fast. You can go from 10,000 riveters to 10 million in four years: in four years, you can go from 10,000 aerospace engineers to 40,000, because the training takes so long and is so hands-on. The M4 Sherman could mostly be built on technologies and principles familiar to automobile makers. Those companies could change over their tooling a bit, and 95% of the processes were familiar to them. Try to do the same with an M1 Abrams, and it would take at least a decade. The M4 Sherman was made of steel and mostly mechanical parts: the M1 Abrams is made of advanced composite armor, uses very specific electronics for fire control, and is in general a vastly more complicated beast. If we had to mass-produce a tank in the next decade, it would probably look a whole lot more like the M48 or early M60 than the M1. Same principle with an Orion spacecraft: this isn't something the Ford corporation can just retool to make in a few months, it's a massively complicated spaceship which only a few people have the expertise to build.

The only precedent we have is something like the Apollo program. Eleven years to go from a simple satellite to an exploratory landing on the Moon. A lunar/Martian colonization project would probably take a similar amount of time for systems development, several more years for scaleup, and several years on top of that to build up the colony. In all, I'd estimate 20-30 years. At the amount of stuff you would need (absolutely tremendous), it may actually be simpler just to deflect Pallas: in that case, all you need is to develop Orion propulsion (and possibly supplement with gigantic solar sails) and send up a giant fleet of identical craft to deflect Pallas: no need to develop the vast multitude of systems required for extended survival in a non-terrestrial environment. They could also be simpler Orion craft, as there's no need to put people on them.

I have thought about it. Under any configuration of the problem, there is simply not enough time for anything. We've got nothing to deflect Pallas, and the systems required for sustainable colonization would take far more than four years to develop. The only hope is deeply shielded bunkers. You are proposing we build a huge fleet of Orion spacecraft, specially built propulsion charges (gotta make sure your spacecraft can dispense them), and radical equipment to support a colony, all in the space of four years. That timetable would barely be enough to build one Orion spacecraft, nevermind a fleet of them. EDIT: Also, Wikipedia says 800 0.15kt charges to get a 4,000 ton Orion craft to orbit. Not many nukes go that small, and they have to be small, or you'll kill any human crew aboard with the sudden impulse.

Okay, so we have a lottery for the three seats which aren't occupied by people with 100% essential skills. People aren't going to be impressed by a 3 in 7,000,000,000 chance.

And now that I'm looking at the human part of it: What you suggest would be a very quick road to riots everywhere. People would support a last-ditch save-the-species act. They wouldn't support a tyrannical regime bent solely on getting a few technocrats to survive. Granted, it likely wouldn't be necessary, because there's only so much you could possibly pour into the aerospace industry (not every engineer needs his own personal petaflop supercomputer), but the support would dry up very quickly if went from being viewed as "salvation of the species" to "excuse to persecute everybody but the 0.000001%". Also, back to what I said about the aerospace industry: the number of people who know what the challenges are for designing a lunar vehicle is very small. You might get a thousand designs for a lunar bulldozer, but only the three or four which came from aerospace companies would work, because only those few companies have engineers who know offhand that they have to account for low lunar gravity, the absence of atmosphere, the composition of the regolith, and how to make it lightweight. Half of them would do something silly like neglect to account for lower traction on the lunar surface, half of them would forget "oh, no atmosphere for our gasoline engines", half of them would use the materials they're used to, like steel, instead of lightweight alloys, etc, etc.

Ezin, that is rather hopelessly naive. An Orion craft is a complicated system: you've got to have a system capable of dispensing atomic bombs at very regular intervals. The shock absorber has to absorb a titanic amount of force, and not break if one bomb is a dud. Nobody has tried any sort of system on this scale, and I'm not even much familiar with the challenges of Orion craft design. On top of this, you have to build a spacecraft larger than anything we've built to date: just the design for the spacecraft section is going to take months at an absolute minimum, and it'll be riddled with problems. There are not very many companies which have the expertise to build such systems: it's not like building an M4 Sherman, it's like building a Gerald R. Ford supercarrier from dead-scratch. There simply isn't time to "try it ten ways", because the aerospace industry is going to be strained past its limit to try even one. There just aren't enough engineers with the expertise to do this! You show a clear lack of understanding of how complicated such an endeavor would be. We might, if we abandoned safety protocols left and right, make a single Orion craft in four years. Enough to make a sustainable lunar colony would be outrageous, and there would probably be no time to design the lunar habitats: the Orion craft would stretch us to the limit.

Eliminate the check from the source code, recompile, and don't expect any support from the mod authors.

And how many of them remotely approached the novelty and scale of an Orion-drive spacecraft? The only thing which came close is the Manhattan Project, and that took three years for a singular goal: making enough weapons-grade uranium and plutonium for functional nuclear weapons. Everything else for the Manhattan project was either in-place (heavy bomber delivery systems) or simple (making the actual bomb). Orion goes far past that. Not only must the spacecraft be designed, you have to design everything for a self-sustaining lunar colony: the machinery, the radiation shielding, the agricultural equipment, almost ad infinitum. There are a huge number of things which have never been tested, this goes far beyond the scope of any prior space project, and it's almost certain to fail. It is also of much greater scope than you imagine: a self-sustaining lunar colony would basically need millions of tons of heavy industrial equipment sent, because they have to make their own everything, and a little 3-D printer isn't going to cut it. This has far more in common with the Apollo program than the Manhattan Project. There are a huge number of untested subsystems, and even with all our resources devoted to it, there's something which will go wrong, and without Earth to send you a size-6 defloppulator when yours breaks down with no replacement, the entire lunar colony is screwed.

It's not hard. It's tedious, slow (particularly when summing a lot of part/fuel masses), and you have better things to do than manually grind out dV.

Being stranded on Mars does tend to give you that impression of one's situation, doesn't it? Also, being blessedly unaware of what the impact would do, I'd be cautiously optimistic about deep-underground or underwater shelters opposite the impact site to wait out the apocalypse.

Are you sure you had symmetric fuel tank drain? Docking and undocking can do strange things to a craft's tree structure.

No. If you can conceive of it: no. If it could be practically done on current technology on a few years' notice: no. Just no. We're talking about a rock which, upon being hit a billion-ton impactor at 10 km/s, would change its velocity by a whopping 50 micrometers/second. The rule of thumb about supernova-related numbers applies here: whatever number you're thinking of, it's too small. In your case, you're talking about a bomb with the mass of 4 Tsar Bombas. In terms of raw energy, it looks vaguely promising: with 400 MT TNT yield and 100% energy transfer, you could change Pallas's velocity by 12.6 cm/s. Problem is that you aren't going to get anywhere remotely near 100% transfer into kinetic energy: bombs are a terrible way to get kinetic energy. My best estimate (working off what's available from the Wikipedia page on Orion vehicles*) suggests about 0.03% efficiency, and that's with what amounts to a shaped charge firing at a pusher plate designed specifically to absorb that energy. *0.15kt charges, 4000 ton vehicle, ~10 m/s dV from each charge. Even just avoiding a direct collision is an almost impossible feat, much less trying to get it to intercept the Moon. If we can get a velocity change of a few centimeters/second, that's probably enough. Problem is, we've got nothing to move Pallas by even that tiny little amount, on account of Pallas being so huge that human minds simply cannot grasp the magnitude of it.

Well, as I see it: if the Big Dumb Booster concept made economic sense, people would be making BDBs. People aren't making BDBs. Therefore, BDBs don't make economic sense. Part of it I suspect is the tyranny of the rocket equation: a heavy upper stage means a heavier lower stage. It makes a large amount of economic sense to optimize your upper stages. You could apply the BDB concept solely to the first stage, but that means development costs are going into a concept only used for one part of the rocket.

Greenhouse gas emissions are a long-term threat whose significance has been much clouded in the public mind. It's just not the sort of thing to trigger "MUST SOLVE NOW" in the human brain. An asteroid is a concrete thing, much more like the threat of nuclear annihilation hanging over America in the 1960s. There would be a huge response to an asteroid, much like the American effort into rocketry in the 1960s. It would be a "MUST SOLVE NOW" problem. There would be a huge international effort, which would utterly fail, because Pallas is simply too big to move, and the timeframe far too short to set up any sort of viable interplanetary colony. With a few more decades, we might dust off Project Orion, and use it to deliver solar sails to Pallas and/or just use nuclear pulse propulsion directly, but 4 years is basically doom-for-everyone. And don't think it would be a few Orion vehicles. It'd have to be probably thousands to millions of the things. For that matter, it might be capped by the amount of radioactive material we're willing to spew onto Earth's surface and atmosphere, forcing us to supplement it with conventional rocketry.

And yet it's much cheaper to send two entirely separate robots whose sole purpose in life is to pick up one rock each and carry them to a return rocket. Stuff on Mars isn't moving anytime soon, and humans are extremely expensive. Difficulty and timeframe are much more solvable problems than trying to worm the funding for a manned mission out of Congress. A manned mission would be a wholly irresponsible waste of money: while the sciences should get more funding, the return rate on manned Mars missions would be poor.

For most things, this can be solved by sticking a probe core on top of your pod. The only sticking point is early career mode, where you have no probe cores, but that bit of silliness can be modded away (I like the 0.4t probe core offered in Modular Rocket Systems).

Though, thinking about it, it might make a great sci-fi short story if you made the scenario more believable: 50-150 years of lead time, a few orders of magnitude less mass on the impactor, and a colossal solar sail project to redirect it, as well as a base on the impactor to help build and maintain the array.

Don't forget their corporate sponsors! I wouldn't usually do political humor, but the question is so ridiculous that it deserves ridiculous answers, like maybe praying a wormhole pops up near Saturn so we can go explore a black hole.

Were you using kinetic energy? You should be using momentum. If I did my math right, 10 cubic meters of osmium traveling at 60 km/s relative will impart enough momentum to Pallas to change its velocity by a whopping 60 picometers/second. p=mv m1v1=m2v2 m1 = 10 m^3 * 22600 kg/m^3 = 226000 kg v1 = 2*Earth's orbital velocity ~= 60000 m/s m2 = 2.11*10^20 kg v2 = m1v1/m2 = 226000 kg * 60000 m/s / 2.11*10^20 kg = 6.43 * 10^-11 m/s = 64.3 pm/s EDIT: If nothing else, this thread has given me a significant appreciation for the ridiculous size of Pallas. I suspect the shortest survivable lead time is on the order of 100 years, and that's including options like "colonize Mars". Maybe some hardened bunkers somewhere might survive the impact and provide a shorter time-frame solution, but it'd really do a number on everything on Earth.

According to that analysis, you can probably shave off ~99% of my solar sail mass. Probably even more, because that estimate is probably a rule of thumb for short redirect time. We're now down to 5 million km^2 of solar sail, massing a mere 50 million tons, for 80 years of lead time.

The energy released from a Pallas impact at escape velocity is about 3*10^28 J. The energy required to melt Earth's entire crust is 2.9*10^28. Do you really think anywhere on Earth's surface would escape?

I don't think you quite understand the sheer size of Pallas. It is 2.11*10^20 kg. A billion tons of impactors going at 10 km/s would change its velocity by something on the order of 50 micrometers/second Even a hundred years of lead time would be difficult. In order to get a 50 mm/s velocity change over 80 years, ignoring the mass of the solar sails, you would need 500 million km^2 of solar sail. I may have done the conversions wrong at some point, but given my only reference value (10 g/m^2), that is 5 billion tons of solar sail. EDIT: I also assumed (really badly) the same thrust you'd get at Earth. Pallas is further out, the thrust should be lower there. I also slipped a few zeros on the impactors, on account of dividing by a billion kilograms instead of a billion tons. EDIT #2: Where did I get ^21? Woohoo, I get to slip a zero. Not going to change the final results much.