Zeiss Ikon

So, when used normally, i.e. goes EVA in atmosphere and left the vessel, the Kerbal is controlling the thing with weight shift? Because it certainly seems there's considerable pitch and roll/yaw (coupled) authority when flying a parachuting Kerbal. Weight shift would explain "Their Legs Move!!" video...

@Slashy Maybe the list has been updated, but Goat Simulator is, in fact, in the list -- you have to go left 4-5 frames from the KSP link given above.

Americans use electric power for heat (mostly heat pumps, how, less energy for the same degree days than resistance heating), cooking, hot water, and clothes driers. We just get it on single phase lines. For those applications, there's no or very little efficiency gain from three-phase (heat pump motors, maybe, but probably only enough to pay for the more expensive service for commercial size units). Farms in the US might use three-phase; it's been about fifty years since I spent any time on a farm, and I suspect it'll vary depending on what kind of farm (if you raise chickens, you gain little from three-phase power, because your energy expense is mainly lighting and a little heating/cooling, but if you process dairy from a large herd the refrigeration might well make it worthwhile to have three-phase power).

I've never seen 3-phase to an American house (though I haven't been in a lot of them). I'm confident there aren't a lot of them, though, because neighborhood feeders aren't 3-phase out at the pole, and it's much more than a transformer to turn single phase dual-hot into 3-phase. IF you want/need 3-phase to your home (for instance, to operate heavy motors in a hobby machine shop), it's often cheaper (over a span of many years) to install a 3-phase converter with Variable Frequency Drive than to get 3-phase power to your house/shed -- because the power company would have to run a special feeder line from the last point where 3-phase was available on their lines, which (for a residential neighborhood) is likely to be the substation.

I grabbed Making History a couple days after it dropped (had to wait for payday, things were a little tight that month). I use the Mk. 1-3 Command Pod on almost every flight now (I fly a lot of 2.5 m hardware, I've just finished the 160 science tier in a career game). I recently used six Skiffs on Lf/O boosters for my crewed Duna flyby (significantly better performance than Reliants, and they can mount on 1.25 m tanks), and I made use of the tiny conical Service Module on a recent mission that needed to "haul" a Mk. 16 parachute, but was flying with a Mk. 1-3 Command Pod. Looking forward to a career in the future that will have two-Kerbal pods and 1.875 m tanks etc. in the part of the tech tree where it matters (I was in the 160 tier when the DLC dropped). Does anyone know if Community Tech Tree has been or is being updated to account for the new parts? I'd be interested in adding "airplanes before rockets" to that future career.

Last night, while waiting for my Duna flyby crew to reach their next burn (60-something m/s down inside the orbit of Eve to set up a Kerbin encounter, and I'll need at least one more correction later to get closer than 5,000 km -- and they're close to bingo fuel, so I have to make that correction still a fair way out)... I had a contract that was going to expire before the next burn, so I decided I'd best take care of it. Hmmm. "Haul a Mk. 16 parachute into flight, between 1,000 and 3,000 m altitude, between 100 m/s and 270 m/s." Well, that looks like I just need to mount it on one of my regular orbital launches, they all hit that parameter set. Only problem is, a Mk. 16 fits a 0.625 node, and a Mk. 1-3 Command Pod has a 1.25 node on its nose. Oh, wait -- I've got all these new parts from Making History! There's a tiny "service module" that brings the Mk. 1-3 nose down to a size to fit a Clamp-o-Tron Jr -- or a Mk. 16 parachute. I mounted that service module to the nose-mounted Science Jr. on my Explorer Vpl (Roman Numeral 5, Passenger, Lander), which is a Mun lander from a couple spacecraft generations back (before the first Minmus mission, anyway), modified by deletion of the redundant controls (can't have "what does this button do?" sending your spacecraft out of Kerbin's SOI). I had a pair of tourists who wanted to land on the Mun, so I grabbed a pilot who hadn't planted a flag there yet (Tridin, a rescue from Munar orbit, as I recall), and away they went. With an additional transfer stage (rather than being expected to get to the Mun or Minmus on the lander's own fuel, as well as land, launch, and return), it was a trivial mission; the transfer stage was able to perform the Munar deorbit burn, leaving Tridin with full tanks for the actual landing and return. Landing was smooth and uneventful; Tridin managed to kill her velocity well enough to get a near-vertical final descent and was able to land with about 30% fuel still in the drop tanks; the core tank untouched. All the science was collected, including scans with the new Surface Scanner instrument; Tridin went EVA to collect a surface sample and plant a flag, reported her experience, then reentered the command pod. Launch from the Mun was trivial as well -- a short burn to give working time, turn over for an eastward boost, then burn (with a little pitch up after a bit to ensure terrain clearance). Once Ap reached 18 km, she shut down, then burned again at apoapsis to circularize. After a wait, she burned for Kerbin, corrected to ensure a prograde reentry, discarded her return module with more than 1000 units of Lf/O remaining (can't really bring it back, can you?), and hunkered down for reentry. Nothing exploded (except the discarded module), and the routine splashdown was within 200 km of the Space Center, despite "take what you can get" on a Munar return. A science haul of about 430, a nice payout from tourists and the test contract -- and the Duna flyby crew is still 180+ days from their Kerbin intercept burn. Right, vs. the multiple days or weeks (not even counting time to construct the birds and mate them to their launcher) that it would take for NASA to launch that series of relays. Edit: Whoa, you mean five hours on the mission clock?! Well, Kerbin is a lot smaller than Earth...

I presume a large part of it is because they haven't discovered the time warp process. Or they have, which is why the NASA/SpaceX/Boeing/etc. ground engineers never seem to look bored after their probe has been on the way to Mars for nine months. We don't notice because time warp only speeds up time for the "player", not for the world...

The specific fibrillation hazard of 60 Hz vs. 50 Hz AC is well documented -- but by the time it was, the US, Canada, and Mexico were already standardized on 120 V 60 Hz home power, obtained by splitting the legs of 240 V double hot single phase. Still, the fact remains, three phase isn't significantly different in terms of hazard from single phase of the same line-to-line or line-to-neutral voltage. AC is in fact more hazardous than DC -- the zero crossing gives around 2-3 milliseconds when the current is low enough not to galvanize, which is about 1/100 of human reaction time, even at the reflex level, but the AC, if it passes through the heart, disrupts the heart's electrical rhythm (50 Hz can still do this -- even DC can, if the current is high enough -- but it takes a lot more of it than with 60 Hz, which closely matches the natural fibrillation frequency of the heart). Electrical safety documentation in the US notes that 30 mA of 60 Hz current across the chest for less than 1/10 second is sufficient to induce v-fib, which is lethal if not immediately treated. This is why GFCI devices are designed to interrupt power if the imbalance between legs exceeds 10 mA -- to give a margin of safety -- and do it in less than one full cycle of about 16 ms. AC is used for power grids almost entirely because it's easy and pretty efficient to change voltage (with a transformer), so you can do long distance transmission at 200,000+ volts and have very low current requirements (hence not melt your transmission wires even when they're carrying, say, a hundred megawatts), but step down to 1600 for neighborhood distribution, and 240 for residence lines. Three-phase transmission is also easily broken down into single phase when needed, and is more efficient both to generate and for large motors (virtually all electric motors over about 2 HP = 1.5 kW are induction type, which work better on 3-phase than single-phase).

Most 220-240 V mains power uses two "hot" legs -- that is, either wire is hot relative to ground, at half the rated voltage, but they're in opposite phase. That is, one has negative charge when the other has positive, so the voltage between the two legs is twice their potential to ground. A three-phase line can be wired two ways. There are "delta" lines (named for the Greek letter that looks like a triangle), where the load is placed between each pair of hot legs (so three loads -- these would usually be either a resistance element to generate simple heat, or one coil set in an induction motor), and there are (as called in America, anyway) "wye" lines (named for the Latin letter Y, again because of similar shape on a diagram), where the three loads are between each hot leg and a neutral. You can tell them apart at the outlet or plug very easily; a delta line has four prongs or sockets, one for each leg and one for ground (like your 220 V line has three, one for each leg and one for ground), while a wye line has five -- one for each leg, one for the neutral, and one for the ground. The leg-to-leg voltage in both is likely to be 230 V outside the USA (240 V in the USA). A wye line also give 120 V from each leg to neutral, though there's also a "wild leg" setup that puts one leg at 208 V to neutral. Either way, a shock from a 3-phase 208-240 V outlet shouldn't be any worse (or better) than one from a single phase 230-240 V outlet -- either one is likely to give severe deep muscle burns as well as surface burns. Fortunately, your European 50 Hz is significantly safer than American 60 Hz in one regard: very low current shocks (typically delivered by contact with dry skin and a poor ground) won't kill you by stopping your heart. With our 60 Hz, as little as 30 mA across your chest can result in ventricular fibrillation which, without immediate CPR (ideally including use of a defribrillator) will kill you in a very few minutes.

Well, this is the old classic method of integrating a "nasty" expression -- draw a graph on paper of known "weight" (mass per area), cut it out carefully, and weigh the cutout on the most precise scale you can find. Then again, there was a mechanical device for numeric integration: the goniometer. I have no idea, mechanically, how it worked, but it had a base and an arm, and it would measure the area when you traversed the edge of an irregular figure with its pointer. You could use it, for instance, to measure the work done by a steam engine during one cycle by integrating over the pressure/displacement diagram (which, in turn, was drawn by a mechanical plotting device -- I saw the plotting device operate on a steam engine in the engineering lab at U of Idaho, back in 1979-1980 time frame). Today, of course, you've had a pressure transducer and a shaft encoder, and a computer would spit out the work per cycle in real time as you vary the cutoff, throttle, and load. But there were ways, as far back as the 18th century, to get from, say, a series of observations that yielded nothing more than a 3-D bearing from a point on Earth's surface for a series of observation times/dates, to plotting the orbit of a newly discovered object (this was done for comets before the first asteroid was discovered and named; the method was worked out by Kepler, refined by Newton).

There will be, but it won't be visible from Japan. In fact, given the solar panels are either fixed to the satellite frame or track the sun, you'll tend to get either no glint at all (in the latter case) or momentary glints far from the service area as the spacecraft continuously reorients (presumably using reaction wheels) to keep the antenna pointed at the correct part of the Earth. The geometry of reflection is such that you'd need to design the spacecraft specifically to put the glint where the signal is going; normally it'll be cast far away, likely even missing the Earth entirely most of the time.

Yeah, it works a lot better if both orbits are drawn on the same center. You can actually see and measure the eccentricity of Mars's orbit relative to Earth's on a quarto-sized book page (though that may be more due to the arguments of periapsis differing by around 120 degrees than due to the magnitude of the eccentricity of either one). The orbits look circular to the eye, but they look like they're off center. Get a caliper or finely divided scale and you can measure the eccentricities in that size and the space between orbits is off-center. It's worth remembering that numeric methods greatly predate what we'd think of as modern computers; the earliest n-body orbit work was done with slide rules, mechanical calculators (or even Napier's Bones), and MUCH iteration. For something as "simple" as calculating a transfer window, you don't need multivariate differential equations; the early iterations would be done with a slide rule and refinement to acceptable accuracy with either an early computer or a mechanical or electronic calculator (mechanical calculators with enough accuracy -- 10 digits or so, and at least the four basic functions -- came along in the same time frame with typewriters, late 19th century). These methods worked well enough that Herschel was able to predict the location of Neptune from the perturbations in the observed orbit of Uranus -- in the mid-19th century! Drawing accurate ellipses (without computer software) requires a special tool called a "trammel". A draftsman's version of this can draw about as accurately as a draftsman's compass (call it .1 mm with a good instrument and skilled user), and is adjustable for semi-major, semi-minor, and orientation of the semi-major axis (IOW, it can draw any ellipse bigger than its base and small enough for the arms to reach). Don't forget, too, that no one cared about m/s level of accuracy for transfer orbits until it became possible to actually launch spacecraft that could perform the transfer -- and by then, electronic computers existed (though a mainframe that filled a couple rooms had about the computing power of a modern graphing calculator -- still capable of doing the work, just took a long time to produce a high precision result).

For the simple case -- a Hohmann transfer between planets in adjacent orbits (Earth to Mars, Earth to Venus, etc.), you can eyeball the window, at least to the precision needed for an initial burn. You need a chart of the planetary orbits, printed to scale (with accurate eccentricity) and the planetary positions marked accurately for a reference date. The Hohmann ellipse will have a period exactly halfway between the departure and destination orbits, so you move the target planet forward in its orbit by that number of days, place an ellipse to touch both orbits with the departure contact on the departure date, then move both planets and the Hohmann orbit forward and back in time so that the target orbit contact occurs on the arrival date. I know this method works, because we used the chart in the Field Guide to the Stars and Planets, along with the supplied ephemerides (for planetary periods accurate to fractional seconds) to calculate windows from Earth to Mars when I took high school physics in 1974. I used a slide rule for the class; calculators were too expensive.

Sounds like you might want to unlock Miniaturization next...

That's close to the standard inclination of a tundra orbit -- as I recall, they run at 63.5 degrees to avoid destabilization by Earth's equatorial bulge, with a 24-hour period. That's done so they stay near-stationary in the sky for a period of some hours near apogee. These orbits have been used for comsats over Siberia and other high-latitude markets, usually with three satellites deployed so there's continuous service (otherwise, a single satellite will be within the lobe of a fixed antenna for only several hours of each day). Your 85 degrees above horizon might be anywhere between 47 and 57 degrees declination, depending on direction of displacement from the zenith, which is about where you might see a tundra orbit comsat when it's a little off its apogee (but likely still in the service dwell zone). Such a satellite would move only several degrees per hour when in its dwell region, so would seem fixed over a three minute sighting. You're right, an Iridium flare would seem to move several degrees over a span of three minutes, though that's hard to detect near the zenith without references (stars, which weren't visible at the time of your sighting, or fixed objects like buildings, or a telescope or camera on a steady mount). Another slight possibility -- seems to me a recent Mars mission was launched from Vandenberg, which would give a polar parking orbit before insertion to the trans-Mars trajectory. Apparently this is done because of launch cadence limitations, and the slight dV penalty is preferable over having to push the launch back, potentially out of the Mars window.

Hmmm. Scientist has visited the Twilight Zone and returned -- or has he? Are you certain the scientist you got back was the same Kerbal who crawled out on that ladder?

that's pretty clearly just an airliner or transport jet flying at an altitude where the rising or setting sun is shining on its underside, and the bottom of the contrail. The OP object is most likely an Iridium flare. These look like a point source light, which will expand into a circle if the lens is out of focus (which it virtually always is, if you apply enough magnification to the image). They're brilliant enough to see against a twilight sky with ease, and last a couple minutes. They're produced only by the "old model" Iridium sat-phone satellites; the Iridium Next have a different arrangement of solar panels and don't cast a reflection to Earth in a way that's visible as a flare. The satellites are in polar orbits (for continuous global coverage), so can appear near the zenith or even in the northern sky, depending on date and solar angle. There's a web page around somewhere that gives exact scheduling of visible Iridium flares -- input your location, and it'll tell when flare will be (or, I presume, have been) visible from your location. It's kept up to date by the company that owns the satellites, so won't show flares from older satellites that have been deorbited or moved into "reserve" orbits.

No. When you load a quicksave, the entire game (except the "library" of vessel designs) is reset to the state it was in when you hit F5. OTOH, that means that if you load your quicksave, made just before you landed, your engine won't be broken; you'll get another chance (or as many chances as you need) to land without that (presumed) error.

Hmmm. Might need to make yourself a checklist. Real astronauts and pilots use them a lot.

Ugh. This game is hard enough without that...

Yeah, I think it's worse that that, @MaverickSawyer. At 1/10 the diameter, Kerbin is 1/1000 the volume of Earth. That would give 1/10 G if it were the same density as Earth (though if it were the same materials, it would be less dense, because even IRON compresses a good bit when there's a whole planet sitting on it). It would need ten times the mass to get back to 1 G (gravity is linear with mass, inverse square with radius). Earth is denser than iron, overall, because the iron core is compressed (offsetting the less dense rock of the upper and lower mantle and the still less dense crust), so you'd need something twice as dense as tungsten or gold -- which is a good big denser even than osmium. IOW, Kerbin and all the other bodies in the system must have cores of (at least) degenerate matter, with the electrons at least partially crushed down into the nuclei. Oddly, the asteroids don't seem to have this; they're about the right size to be made of ordinary rock.

Can't. That buggy is in an entirely different game, the 15 year old open world MMO called There. Originally, it was a sort of "Second Life for people with ordinary computers," though it hasn't grown into the extreme level of complexity and mercantilism Second Life has. The open world is the size of Earth, roughly, with land area (a few dozen islands) about as large as Connecticut (maybe Maryland now, they added a very large island a few years ago), but instead of exploding at the drop of a Kerbal, an avatar can fall from the edge of space and just bounce on impact. Everything in that world is indestructible. So, completely not comparable, I just get a little crossover in my mind when i see someone driving a buggy up a mountain; reminds me of driving up Snow Top, which is 8300 m tall. Good grief, that's what the "revert" is for!!

If you had a planet 128,000 km in diameter, with the crustal density of marshmallow and the compressive strength of granite, you'd be close to the right values to get 1 G at surface. Kerbin's overall density must be more than triple that of Earth in order to have the same gravity in 1/10 the diameter. and to go ten times larger than Earth, you couldn't have the density more than about a third that of Earth -- uncompressed water is close to right (except that either liquid or pressure ice compresses under the weight of 64,000 km of water above it -- I'm not sure what that is in gigaPascals, but it's a bunch). I doubt you'd reach degenerate matter conditions, but you'd have to start with something much less dense than water to wind up with 1/3 the Earth's density at ten times the diameter.

Hmm. Different games, different ways. I keep looking at that mountain and thinking how fast I could drive up it in my Solid Pine Buggy in There. And then I remember that buggy can also fall from the edge of space without damage, can climb a 75 degree slope at above 100 km/hr, and drive 400+ km/hr on the ocean. Used to be faster (above 550 km/hr) before they put a meter of water on the smooth blue concrete ocean floor... Okay, on topic: Last time I played (couple days ago) I launched a mission to carry tourists to the Mun, and fulfill a couple other contracts, while waiting for the first Duna flyby crew (in this save) to return home (they were 230 days from their correction burn on the return trip when the Mun mission launched -- prompted by realizing a test contract would expire before they got home). I hope they'll be okay; I remembered after they entered Duna's SOI that I used an existing launcher with extra boosters and a larger upper stage tank -- and it has only 60% of the ablator (the other 40% removed to save launch mass, since it's redundant on Minmus return). Now, Minmus return at around 3000 m/s still only burns about half the 480 units of ablator. Maybe I can bring them in below 3500 m/s if I can get a Mun assist. Or maybe I can make a couple aerobrake passes with the transfer stage still attached. There has to be a way to get them back safely.

Actually, i recall Kerbal height being given as about 0.75 m -- hence they're comfortable in a 1.25 m capsule diameter (a human can fit into a narrower rocket stack than that, but he won't be reclining in a good position for maximum G tolerance (look up the Danish group who are planning to launch a human in their sub-1 m diameter sounding rocket -- that guy is likely to black out during boost). Mercury, the analog to the Mk. 1 Command Pod, was 2 m diameter, and astronaut height was limited to 180 cm to ensure they'd fit into the couch (at least one astronaut "shrank" an inch just before they were officially measured).