architeuthis

Thanks for your help Leonov:) This is an interesting idea that I hadn't at all considered. I've read though that for single thread processes the 3570 performs substantially better on benchmark (like 30-40% better) than the A10-6800. I don't build terribly big craft in KSP, but I do look forward to less lag so I'm interested in the single thread performance angle. This selection would only cost about $20 more overall. Also I'm not terribly concerned about future proofing my socket choice, I likely won't be upgrading again for another 3-4 years down the road. What are your thoughts?

Leonov, thanks for the helpful suggestions! I don't plan on using SLI, but I would like to do as much overclocking as I can get away with using the stock heatsink (this is also the reason I was looking at the 3570K). It looks like the H77 doesn't have much overclocking support and may only be $20-30 cheaper. What do you think?

Hi everyone, I've been thinking about upgrading so I thought I would try to collect your'alls thoughts. I tend to upgrade my computer on a roughly 4 year cycle. These are the current specs: ASUS M4A89GTD PRO Radeon HD 5750 1GB AMD Phenom II X4 955 Black Edition 3.2GHz I'm giving myself a roughly $500 budget for an upgrade and have been looking at these components: i5 3570K GTX 660 ASUS P8Z77 Do you suppose I'll see much of a performance increase? Might I see better performance with this budget by selecting different parts? One objection I foresee is that, on paper at least, the Intel processor is not a huge step up from the old AMD one. One of the things motivating the upgrade is that the current AMD cpu has been running extremely hot (~80C) lately, even when idle. I suspect a temperature sensor has failed. Anyway I'm treating this as an opportunity to switch to a more KSP friendly processor with better single core performance. What do you guys think?

Sure, it's a ratio of exhaust velocity to the acceleration of gravity. Specific impulse is popular in part because the seconds unit means the value is the same irregardless of the dimensional system (I.e. no mucking about with meters or feet).

It seems like various posters here are speaking mutually unintelligible languages. Lodestar makes a typically Chalmersesqe assertion that our materialistic knowledge about the biology of the brain doesn't do anything to solve "the hard problem" (the existence of subjective experience), which is essentially a pure philosophical problem, and thus biology is worthless as far as engineering a synthetic consciousness goes. Nevertheless there are obvious empirical links between the state of our subjective experience, and the material world. E.g. if someone destroys my brain, my subjective experiences will cease. I think it is entirely possible that with more years of tinkering we may build conscious machines even despite our primitive understanding of the neurobiology of consciousness and having still left these lingering philosophical questions unresolved. That said with regards to the OP, if it means doing spatial simulations with high levels of physical fidelity in real time, then it doesn't seem likely to happen any time soon. The required computer technology is many orders of magnitude beyond current capabilities. On the other hand if you're using comparatively simple integrate and fire models, or Hodgekin-Huxley models than the simulation is much more tractable. There is some agreement among neuroscientists that action potentials are the fundamental form of communicated information within the network, so this level of abstraction may be totally acceptable. The C2 model by Modha et al. is an attempt to simulate a neural network on the scale of the brain of a cat, this simulation would have a network with over a billion nodes and 6 trillion connections. The model uses a simplified representation of neurons, synapse states are described by only 16 bytes of information (or 16 characters in other words). This requires at least 96 TB of memory and additionally since the states of each node are updated once per millisecond and the behavior of the node is governed by a set of differential equation, we have 1E9/1E-3= 1 trillion solutions per second. Fortunately supercomputers such as the IBM Blue Gene /P used in the model are capable of satisfying these computational demands. Even more recent supercomputers are capable of quadrillions of floating point operations per second, and may have thousands of terabytes of memory. This seems to imply that, at least using a simplified neural model complete simulation of a single human brain is almost within reach technologically even today.

Nice work!

Lift force is always normal to the fluid velocity even if the subject of the force is weightless. This is why it is sometimes useful to add fins to rockets: the lift force is proportional to the angle of attack, thus if something disturbs a rocket such that it is no longer pointing in the direction of fluid velocity a lift force is created. If the lift force's line of action acts through a point behind the center of mass, then this lift will produce a torque that will tend to correct the rocket's angle of attack back to zero. So the fins make the rocket dynamically stable, even though the lift force is not acting in opposition to gravity in this case. Regarding the OP, it's a really interesting question! Lift coefficients are functions of an object's shape, Reynolds and Mach numbers, and effective roughness ratios among other things. I've heard that nebulas can be quite hot, but I'm guessing that even despite that viscous effects would be basically negligible, and so we would mostly only need to worry about the shape of the object. Let's say some crazed alien art collector of the far future towed an ancient Earth-Human Boeing 747 out to the Orion nebula and mounted it to a relativistic rocket kick stage for the purposes of creating an avant garde installation. The 747 has a wing area of 541 m^2 according to wikipedia, so the velocity needed to generate a single Newton of lift given a 45 degree angle of attack would be 6.12E6 m/s or about 0.02 c.

In principle I agree that gameplay should take precedence over realism, however overkill realism is not the PB-Ion's problem. They are probably the most ludicrously unrealistic part in the game (even more than the reaction wheels:)). But the isp vs thrust tradeoff is something that is pretty fundamental to rocket propulsion. Ion engines are defined by their high isp and low thrust, chemical rockets are defined by their low isp and high thrust, nuclear thermal rockets are somewhere in the middle. Low thrust means long burns, that's just how it goes; if there was a high-thrust high-isp option why would we ever use anything else?

The Moon, because it's beautiful and because it makes me smile every time I see it in the sky and realize that we've once racked our gloved hands in its chalky regolith, and perhaps will again. Phobos, for its frantic orbital period. Enceladus, for its aquamarine tiger stripes. Tethys, because it is not so much a moon as it is a spacestation (do you suppose that the rebel base is on Titan?). Iapetus, for being shaped like a walnut. Triton, for resembling a cantaloupe. Charon et al, because we're about to learn so much more about them.

No regrets. In many ways the Saturn V was only a minor corollary development of the ICBM. In fact the Redstone, Atlas and Titan rockets the Mercury and Gemini astronauts used for their rides to orbit literally were ICBMs. We took these machines designed with the express intent only of mass destruction, and which are still easily among the greatest and most powerful machines ever built, and used them to send ourselves (physically or otherwise) to other worlds. For the vast bulk of our species existence on this planet this wasn't even science fiction, this was beyond the scope of imagination. The planets of our solar system were just points of light, nebulae and galaxies were small smudges in the sky. No longer. As long as dreamers keep gazing upwards at the milky way and thinking if the future I will have no regrets.

It would be used by real life astronauts who don't have kerbal style time warp, and won't get bored by month long burns. If you want high thrust use the LV-N, if you want ridiculous amounts of delta-v use the ion engines. If you want both... download a mod and use warp drive.

Regarding spacewalks, I think it would be really neat if there were more things to do out there besides sightseeing. As suggested above it would be cool to use EVA for in-space repair and construction work. In reality space is a harsh environment and things are constant failing and needing to be replaced. Solar panels degrade with time, pumps and plumbing for heat rejection systems fail regularly, and just in general parts wear out from extreme thermal cycling fatigue, constant exposure to sunlight and hard UV exposure, atomic oxygen corrosion and impacts of micrometeorites, vacuum cold welding, Paschen discharging etc. Random failures of propulsion, communication or attitude control parts could make a need for EVAs more regular. And hilarious unexpected failures add to the fun and excitement of a mission. Also on-orbit construction of space stations should need some EVAs, perhaps Kerbonauts can assemble trusses while on EVA (and obviate the need to put those ridiculous fully assembled trusses on launch vehicles).

The stock ion engine is already substantially more powerful than a VASIMR.

Childhood's End is often put forward as his most important novel, and 2001: A Space Odyssey was a "novelization" of the movie, though the movie was based on his earlier short story "The Sentinel" (which was a good read). My list would be: The City and the Stars A Fall of Moondust Earthlight Rendezvous with Rama The Fountains of Paradise

Simon is making a practical argument, I fully agree that we will probably never see a manned Mars mission using chemical rockets alone. For instance SLS (assuming it is built) will have less than half the payload to orbit of the Ares V, so make that 24 launches for sake of argument. Currently they plan on launching them at a rate of 1 every other year. Therefore 48 years to build the Mars fleet. And this assumes zero losses to cryogenic boil off (i.e. indefinite storage of liquid H2 in space), a technology which is as yet undeveloped. So technologically possible, in theory perhaps. But in realty? I do not think so.

I second that. Also the NASA-bad private industry-good arguments. North American Rockewell designed and built the Space Shuttle. Martin Marietta built the external tanks, Morton Thiokol built the solid boosters, Rocketdyne built the RS-25 SSMEs. Also to anyone who thinks big corporations (e.g. most aerospace companies) aren't bureaucratic, try working at one. David Portee's Beyond Apollo post linked in the OP posed an interesting question. He seems to imply that it was not NASA particularly that lost it's nerve after the loss of Challenger, but that America herself shrank away from the danger and challenge of spaceflight. The Challenger accident itself was stupid and avoidable. But was also terribly symbolic. It is completely self-evident to me that the taming of a frontier as harsh and extreme as space will not occur without sacrifices. Martyrdom for seven people for the conquest of space. Accidents were expected to happen eventually, but the question is why did it test our resolve so greatly and how did we abandon our ambitious, glorious dreams so easily when the inevitable accident did finally happen? Are we not stronger than that? D Portee implies that bold as NASA was during the moon race something similar happened after the loss of the Apollo 1 crew. It wasn't the successful landing of Apollo 11 that led to the rapid decline of NASA's budgets, and the scaling back of its expansive future plans to just the Space Shuttle (and even that was historically tenuous), the American people had already started abandoning NASA after the Apollo 1 fire, and Apollo 13 made it assured... Werner von Braun might have seen a manned Mars landing in his own lifetime...

I always thought by Ken MacLeod, who did most of the rest of KSP's soundtrack, would make good VAB music:)

New plan: lithobraked terminal decent mode.

Orbit exits SOI; Still burning prograde.

Fix staging order; then conquer space!

It would be nice if solar insolation followed the inverse square law. I agree with the OP that RTGs could be made more useful; currently they are mostly advantageous only for planetary surface missions with large power requirements (i.e. rovers). For surface bases it is probably easier to just use large batteries (I imagine when economics are included RTGs will be very expensive if they follow reality as a guide). In general it would be nice if the electricity mechanic was a little more fleshed out. I made a graph a while ago showing power levels for several solar panels if insolation from Kerbol did follow the inverse square law. Just for kicks it looked like this: *y-axis is to log scale. *For reference Jool is about 5 KU away from Kerbol.

You're right, Earth to orbit is a big part of the cost problem. NERVA has probably 3 times the specific impulse of a chemical rocket, this means that for the same delta-v mission to Mars the required mass ratio drops by half. Which is a way of saying you can do the mission with like 6 multi-billion dollar SLS launches instead of 12. If the development costs are less than the cost of building and launching 6 SLS's (which seems likely), then NERVA is anything but a luxury.

You would need some special 3rd stage or have to do a gravity assist at Jupiter, and even then it would take tens or hundreds of thousands of years transit time to reach the Alpha Centauri. The solids boosters, core and upper stages together only give SLS about 18km/s of delta-v (assuming no payload). This is not enough delta-v to reach solar escape velocity from Earth's surface:/

Unfortunately that's not how it works. Look at how President Geroge W Bush's Constellation Program turned out. The White House doesn't get to fund anything, that's Congress's job. Which is exactly the problem. For the most part they see space exploration only as a source of federal money for their districts, and that alone predisposes their support or lack thereof for it. Hence SLS. Apollo was an exception to the normal rule, a one time thing, beating the Russians was an ideological test for representatives back then in a way not dissimilar to support for the Iraq invasion was in 2003. If we're lucky we might get another one time thing out of China when congress's sensitive nationalistic pride starts to feel threatened. IMO not a very sustainable paradigm for space exploration in general.

I have mixed feelings about the SLS. On the one hand it could be an amazing platform for all sorts of missions, even if only the block I ever flies 70 tonnes to orbit is pretty impressive. It enable missions that could otherwise only be performed using propellant depot architectures (which unfortunately are no where close to being mature technologically). If you're looking at variable costs SLS should cost $7million USD per tonne to LEO, which way outperforms both the Space Shuttle or the Saturn V as HLVs go. On the other hand they are talking about launch rates so low that there isn't going to be any economies of scale, and they will not be able to amortize the (substantial) development costs over many launches. Also as people have pointed out it already looks like, given the current budget environment, that NASA will get trapped into the same cycle they were stuck in with STS, which is that the launch system and its support infrastructure is so expensive that they won't be able to afford developing any interesting payloads that could actually use the rocket's considerable capability to its full potential. Part of me sees that for many American politicians the SLS is a useless jobs program, and that makes me want to ditch it just on general principle. Another part of me knows that if SLS gets cancelled NASA won't have a HLV for probably another decade or two, and though I have lots of faith in Elon Musk and SpaceX I don't see the Falcon XX coming to the rescue anytime soon. These things take a while to develop, even if there is a mandate and a solid budget, which currently there is not. There aren't really any serious efforts to develop flight qualified NTR or propellant depots systems that we would need to say, go to mars for real using only Falcon Heavy class launchers. Do we abandon the progress that's been made (and the 2030 Mars timeline) and try to stick it out by putting our faith in capitalist enterprise? Or do we keep chugging along in the imperfect reality? ... Difficult question for me personally.