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oxy126

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  1. Jetpack Adventures with Jebediah Launch Time: 6/3/14 Team Members: All Play-by-Play: Got into orbit around Minmus (that's really all you need to know). From there, went on a fancy little EVA with Jeb, firing retrograde and trying to judge surface velocity by eye (no navball during EVA)! Managed to land successful with Jebediah alone on Minmus without any horrific accident, planted a flag, and managed to successfully rendezvous with our orbital craft without running out of fuel. Just sorta went on home from there. ...awww yeahhh... Time of Flight: About a day. Nothing too terrible. Summary: If you're going to Minmus, you don't actually have to bring your ship down if you don't want too. What we Learned: Jeb is one pretty talented Kerbal. Moving forward: SPACEPLANES! Milestone awards: Nothing, unless simply being super cool counts. Available funds: Still a fairly large amount. To Laythe maybe? Then we could go get a milestone reward AND use our spaceplanes too... (Laythe does have an oxygenated atmosphere)
  2. Team Name: Big & Low LLP Available Funds: $850 k, maybe (around there) Vehicle Name: Tricky Minmus (because it's so tricky) Parts List (& Cost): Command Pod Really small fuel tank 4 x Small Radial Engines Parachute 4 x Solar Panels Decoupler 2 x Those big fuel tanks Mainsail Engine Total Cost: I don't really know, I'll check (should be ~$30000 though - not very much) Design Goals: Get into orbit around Minmus. Why, you ask? Haven't we already done that? Yes, in fact, we have. But this time we're landing on it Without a ship! (Jetpack only) Launch Goals: Orbit around Minmus, then descend with brave Jebediah sans ship Pilot Plan: Go to Minmus (you don't need details, right?) Forgot the picture again. Just sort of use your imagination.
  3. A Glorious Return Launch Time: 5/30/14 Team Members: All Play-by-Play: After the lack of fuel experienced by Jeb, it was time for us to go save him. As such, we had a perfect opportunity to practice both our interplanetary travel, and orbital rendezvous skills. Seeing as it was really only the landing on Duna that left us without enough fuel, we decided to reuse our previous craft, just stripped of landing gear and parachutes, with a remote control probe added in and an empty command pod. The goal was to get really close to Jeb's ship at a ~330 km orbit away from Duna, then simply have him EVA over to our ship. Everything went off without a hitch, and soon after (by soon I mean about a year and a half, waiting for an optimal departure date) we headed home, aerobraked into Kerbin, and splashed down gently. Mission success. First off: the missing picture from last mission. Our landing was... interesting. No crash, but we tipped quite handily. Took us a while to get right side up again. Parachutes 'n' stuff on the descent: ...Whoops: A picture of Jeb's old craft in the background right after pickup. Forgot about an EVA picture (which would of been cool), but this will have to do: Time of Flight: Once again, pretty long. About three years. Good thing Kerbals don't eat or anything. Summary: Two missions, one with a Duna landing and the other with an orbit? Call that a success (though our craft has been lost) What we Learned: We're never gonna' give you up, Jeb Moving forward: Throw a lavish party with our earnings Milestone awards: Duna Landing + return (finally completed by Jeb), Duna Orbit (by our rescue probe) Available funds: A lot, and soon to be even more.
  4. Team Name: Big & Low LLP Available Funds: ~$500000 Vehicle Name: The Return of the King Parts List (& Cost): Command Pod Remote Control Unit "Poodle" engine 2 x Sorta medium fuel tank Parachute Decouplers Big fuel tank + Mainsail Engine 2 more Big fuel tank + Mainsail Total cost: ~$137000 Design Goals: Rescue poor stranded Jebediah, and return him back to Kerbin Launch Goals: Get to orbit, wait for optimal transfer to Duna, then head on over, rendezvous with Jeb, and come back Pilot Plan: Standard gravity turn to orbit, then wait for optimal transfer time/phase angle to head to Duna (calculated with handy dandy online resources). Escape Kerbin, then wait until encounter with Duna. Circularize our orbit, rendezvous with Jeb. Then, have him EVA over to our ship and return home. Image: Yeah it's just the same one we've used for pretty much everything.
  5. The Sad (But Hopeful) Tale of Jebediah Kermin Launch Time: 5/28/14 Team Members: All Play-by-Play (pay attention kids): Everything was going just swell before Duna. Fuel was being drained as expected, and all was well. However, it seems guestimations on fuel just don't cut it, because, while technically right, we we're right on the margin. And human error is always a factor. Our initial goal was to aerobrake into Duna. Consulting my handy delta-v chart, I felt this would be all it took to land a craft on Duna, and we could ignore (most) of the delta-v on landing, giving us more than enough to return with. Turns out, Duna's atmosphere isn't just thin - it is very thin. Had I lowered it more and tried to use parachutes, I could have had more effective aerobraking, but thinking there was enough fuel in the tank, I opted instead to use rockets. Sadly, once getting down to the surface, I was quick to realize there would be enough fuel to return home. For the time being, Jebediah is stuck in orbit around Duna, and he probably will be for years. But he will be rescued. (Another sweet pic) I don't really know where the landing photos went. I'll add them in soon. Final orbit: Time of Flight: Like... two years. I sorta waited for the optimal departure time once I was in orbit... Summary: TECHNICALLY, Duna has been landed on. But now comes time for an exciting return. What we Learned: Get to know your destination beforehand. Not being to aerobrake is certainly an issue. Also? Could of helped to make an orbiting station, and do a rendezvous. Would of saved some fuel, though for this mission, we could of easily just added more fuel anyways. And most importantly? Don't give up, not yet. The real mission is yet to come. Moving forward: ROKS (Rescue our Kerbonaut Safely!) Milestone awards: Nothing... for now. Available funds: About 250000, enough for a rescue mission, and a completion of our current one.
  6. Team Name: Big & Low LLP Available Funds: ~$400000 Vehicle Name: Duna Lander Parts List (& Cost): Command Pod "Poodle" engine 2 x Sorta medium fuel tank Landing struts Parachute Decouplers Big fuel tank + Mainsail Engine 2 more Big fuel tank + Mainsail Total cost: ~$150000 Design Goals: Get to Duna! (and back of course) Launch Goals: Get to orbit, wait for optimal transfer to Duna, then head on over, land, and come back Pilot Plan: Standard gravity turn to orbit, then wait for optimal transfer time/phase angle to head to Duna (calculated with handy dandy online resources). Escape Kerbin, then wait until encounter with Duna. Aerobrake (as much as possible) in Duna to get an orbit, then bring craft down for a landing. Take pics, take off, and wait for optimal time to head home. Image: Imagine our previous lander crafts, but bigger, and with more rockets. That's about it.
  7. Launch Time: 5/27/14 Team Members: All Play-by-Play: Everything went as planned. Enter Kerbin orbit, created encounter with Minmus (prograde orbit), then circularized and brought it down to the surface. From there, took off in the same direction and returned home. Pretty cool stuff. (Oh man on the surface) (A little EVA fun. Jetpacks work particularly well on Minmus) (Our ships burn with the passion of a thousand Kerbonauts) (NOTE: not dead) Time of Flight: Not quite sure. We just sort of send Kerbals into space and hope they don't get too bored. Summary: Minmus has been conquered and claimed, and nothing broke in too serious a fashion. What we Learned: If you put enough delta-v into a spaceship, it can be easily re-purposed for loftier goals. Moving forward: Duna. Leaving Kerbin (though hopefully not for good). Milestone awards: Minmus landing and return Available funds: A bunch (~120000)
  8. Team Name: Big & Low LLP Available Funds: ~$120000 Vehicle Name: Mun Lander (although we're going to Minmus) Parts List (& Cost): Command Pod "Poodle" engine Sorta medium fuel tank Landing struts Parachute Decouplers Big fuel tank + Mainsail Engine 2 Solid fuel boosters Total cost: ~$110000 Design Goals: Off to Minmus (one stage to orbit, another for everything else) Launch Goals: Get to Minmus, without explosions or becoming in the cold, soulless void of space. Pilot Plan: Standard gravity turn into orbit, create node for encounter with Minmus to enter a prograde orbit, then stabilize said orbit, bring it down to the surface, fire retro to land, then take off in the same direction and go home. (Yeah, I know: same picture as the Mun lander. It is the same craft though):
  9. Launch Time: 5/21/14 Team Members: All Play-by-Play: Everything went as planned. Enter Kerbin orbit, created encounter with Mun (prograde orbit), then circularized and brought it down to the surface. From there, took off in the same direction and returned home. Also, did a nice EVA. Now this is a picture: Flag Swag: Time of Flight: ~ 10-ish hours? (sorry I don't remember) Summary: Got to the Mun, and perhaps more importantly, got back without severe casualties What we Learned: Planning is good (we used it this time), and the Mun is pretty cool. Moving forward: Minmus perhap? Though it may be time to head off to another planet, possibly Dres. Also, if another planet is our goal, working on docking is a good plan. That way, we can leave most our return fuel in space while we head to the surface. Though for the Mun, it doesn't matter much. Milestone awards: EVA, Mun landing and return Available funds: 6619
  10. Team Name: Big & Low LLP Available Funds: ~$120000 Vehicle Name: Mun Lander Parts List (& Cost): Command Pod "Poodle" engine Sorta medium fuel tank Landing struts Parachute Decouplers Big fuel tank + Mainsail Engine 2 Solid fuel boosters Total cost: ~$110000 Design Goals: To the Mun! (with one (and a half) stages to get to orbit, and the second to get to, and then land and return from the Mun) Launch Goals: To the Mun, without any mishaps Pilot Plan: Standard gravity turn into orbit, create node for encounter with the Mun to enter a prograde orbit, then stabilize said orbit, bring it down to the surface, fire retro to land, then take off in the same direction and go home. (Ignore post-flight picture: there were once solid boosters)
  11. Why landing on Eve should be the ultimate prize: Getting to Eve isn't terribly tricky. In fact, of all the planets in the KSP universe, it is the easiest to get to, requiring only (when done right) 80 m/s of delta-v. However, landing on it (and returning) is the tricky part. Mainly the return. Landing on Eve is actually surprisingly easy (if, of course, you miss its many toxic oceans). Its atmosphere is thicker than Kerbin's, and hence parachutes work even better on it. But the higher gravity, combined with the thick atmosphere, means it is actually harder to get off of Eve than it is to get off of Kerbin. Basically, imaging landing the rocket you would use to, say, get to the Mun, or Dres, before dropping any stages, on the surface of Eve. Now double it. Said behemoth is what you need to return from the surface of Eve. Consider this delta-v picture: As you can see, it takes (generally) a whopping 12000 m/s of delta-v to take-off from Eve, almost three times that of Kerbin. While Moho is further away, returning from its surface requires only 1400 m/s, and while landing is trickier, the logistics of the operation is significantly simpler. Most basic lander designs can handle that much. In the end, this is an appeal to raise the prize of getting to, and landing on, Eve from half of Moho to more. A lot more. To finish, I'll provide an example of the kind of lander you need to land on Eve. And it is absolute barebones. All it gives our poor astronaut to sit in is a seat, and as is implied this is only simply to get into orbit back around Eve: a return craft must be rendezvoused with in orbit to make the trip home.
  12. The Kerbal Nomogram: What, exactly, is it? The kerbal nomogram is, simply, a nice little diagram designed to help you with your space travels. If you haven't checked it out yet, you can find it on the main aplusphysics KSP page, and I would recommend looking at it before reading this. Consisting of three little "rules", it provides a way to describe the delta-v equation: Substituting Mstart/Mend for a mass ratio instead, it allows you to take two know values (for example, engine specific impulse and the necessary delta-v), and calculate the value of the third one (in this case mass ratio, or effectively how much stuff you can take along) in regards to the former. Simply by using a straightedge to make a line between the two knowns, and then finding the intersect with the third, you can tell what value you must meet/exceed/remain below for a successful spaceflight (if, of course, you take out pilot error). While maybe a bit antiquated, it still provides a quick lookup to see whether or not you have enough delta-v for your flight, or if you need to take a few things off your payload, or if you need to sacrifice higher thrust for greater specific impulse. At the end of the day, it provides a nice tool for testing the feasibility of your flights.
  13. Imagine you are in an orbit. Maybe its a pretty nice orbit, not to far from home, but not too close either. But for whatever reason, maybe because your satellite tv reception is poor or whatever, you decide it's time to move - to another orbit. Conventially, the way you would get their would be through a Hohmann transfer: an orbital operation designed to move you from one place to another. Here's a picture: In this example some lost soul is going from a small orbit to a large one. What exactly is going on? Initially, one end of your orbit must be brought up to the new altitude. For anyone with basic orbital knowledge, this involves burning prograde (increasing your velocity) at one part of your orbit, adding to your orbital energy and effectively increasing your apoapsis (highest point of your orbit). For now you wait. As you are now travelling along in your newly elliptical orbit, you realize that you still need to get into a new circle. In an effort to do this, once you have reached apoapsis, you begin burning prograde yet again, this time raising your periapsis (lowest point of orbit), until it equals the apoapsis. And hence, you have achieved another circular orbit, now at a higher altitude. This is the Hohmann transfer - a simply yet very useful way to modify your orbit in KSP. For most things you'll be doing, circular orbits will be the norm, and hence it is handy to know how to change them. While there are uses for elliptical orbits for orbital rendezvous and there are other transfer methods (such as the bi-elliptic transfer, a slightly more complex, but at times counter-intuitively more efficient transfer), this is the main one you'll use.
  14. A discussion of Delta-V: What is Delta-v? Simply put, it is the change in velocity (delta velocity) from one point to another. There you go, that's all. But why is it important? In rocketry, delta-v is important because it allows you to measure the change in velocity you need to get into orbit, or get to the Mun or do whatever you like. For most space bound flights, delta-v provides a measure of how much "fuel" (essentially) you'll need to get somewhere else, and because the thrust from any rocket is constant is space, this is the main measurement tool used when calculating spaceflight. Usually when talking about delta-v, it represents a minimum. For example, the minimum delta-v required to get a kerbal into orbit around Kerbin is ~4500 m/s. If you are completely efficient in your staging and other shenanigans, you can get into orbit with that much. However, if you turn around and try to instead to push Kerbin into the sun, you probably aren't going anywhere. While delta-v is a convenient measurement tool with rockets due to their constant thrust, energy, power, timing, and orientation all are still incredibly important when planning a space mission. If you mess these up, the required delta-v to do anything will increase significantly. The curious may ask, "why is all of this space travel measured in delta-v, rather than energy?" After all, when dealing with gravitational situations, energy can be an incredibly useful (and still widely used) tool. However, when dealing with rockets, the power generated isn't constant - higher velocities creates a larger power output. While this is a fact critical to mission success and important to consider in orbital operations (more on that later), if you are given a rocket, and a fuel tank, it is much easier to calculate the maximum delta-v of that system, regardless of what you decide to use it for. Energy is a bit weirder. For Kerbal Space Program, many people have been helpful enough to calculate the minimum delta-v for a variety of missions, whether it is to get to orbit, or the Mun, or any of the planets and their moons (the KSP wiki has a nice graph and article here - http://wiki.kerbalspaceprogram.com/wiki/Cheat_sheet). All that's left from their is to build a rocket, and then check to see if you have enough delta-v to get their. Refer to this handy equation: (An image taken directly from the above page, a worthwhile read) Simply put, given the specific impulse of an engine (a measure of efficiency) and the initial and final masses of the rocket (meaning after it has used all its fuel), you can calculate delta-v. Divide the start mass by the final, take the natural log of that and then multiply by the Isp and 9.81 (g) and you'll get your answer. That way you can check whether or not a given maneuver is feasible before trying it.\ But like I've said before, enough delta-v doesn't make up for poor design or execution. Our last spaceflight had (after calculations) about 5350 m/s of delta-v, more than enough to get to orbit. But because our second stage had low thrust, and we spent up too much of our first stage gathering tangential velocity, we failed to circularize our orbit before we started falling back into the atmosphere. We didn't even get close to space, and lost our chance to use all of the fuel we had left when we crashed. So don't nix problem planning for more fuel tanks.
  15. Launch Time: 5/20/14 Team Member: All Play-by-Play: Up until ~20km, everything was going well. However, when transitioning into our second stage, we hadn't built up enough velocity leaving us without enough time to utilize our lower-thrust second stage to push us into orbit before we were heading back down again. We tried to do a rocket-only landing in the water, but right near the bottom our velocity vector went a bit crazy and we would up crashing, killing all those involved. A real shame, but provided some good rocket-only practice. Time of Flight: ~ 5 minutes Summary: Got into a suborbital flight (again), tried reeeallly hard to get up to 70km, but then just sorta crashed. What we Learned: If your second stage has low thrust, make sure to keep your first stage a bit more vertical than normal. While perhaps not quite as efficient, it gives more time for operations to be performed. Also, making preliminary delta-v calculations are helpful. To get to orbit, at least 4500 m/s are needed, usually more from inexperience and inefficiency. So we should test that before hand. Also, always have a backup plan. Parachutes don't really cost that much in the event of catastrophic failure. Moving forward: Very low in funds, will be doing some research posts soon. However, once a bit more planning is put together, our space station hub will be underway! Milestone awards: If finding out the true meaning of "hard water" is one, then that. Available funds: ~$7000 (but with hopefully more to come) Pictures will be added tomorrow
  16. Launch Time: 5/19/14 Team Member: All Play-by-Play: All went as planned, went up to 5km then tilted over. However, our second stage engine glitched out in game, preventing us from achieving stable orbit. And Matt says "Success but no orbit. The fire, the fire, the fire. But no one died". Time of Flight: ~ 1h Summary: Got onto a suborbital flight path, with a safe reentry. Will be attempting to set up an initial node of a space station next flight. What we Learned: Don't use the weird looking engines. They're all glitched Moving forward: Bit low on funds, but will be aiming for space station operations soon! Milestone awards: 50km manned launch Available funds: $19324
  17. Team Name: Big & Low LLP Available Funds: $30,000 Vehicle Name: First Parts List (& Cost): Parachute (422) MK-1 Pod (600) Solar Panels (4*100) Batteries (80) Decoupler (2*600) Fuel Tank (small) (1600) Engine #1 (Broken) (950/2) SAS Module (600) Adapter (50) Fuel Tank (Big) (12500) Mainsail Engine (850/2) Struts (4*250) Radial Decoupler (2*600) Solid Rockets (2*800/2) Total Cost: 21352 Design Goals: Make a rocket able to get to orbit, multistage initially w/ high thrust, later with high Isp Launch Goals: 50km minimum, hopefully stable orbit Pilot Plan: Straight up to 5km, slow tilt until apoapsis of 72km achieved, then attempt to orbit
  18. oxy126

    Wi-fi

    With new modern forms of wi-fi being developed, there are two things to consider: data compression efficiency and raw speed (which is dependent on frequency). For raw speed, this creates an interesting trade-off: high frequency wi-fi networks can be incredibly fast (some more than 50x faster than normal, not that it matters with most ISPs limitations), but they can't penetrate through walls nearly as well. That's why modern routers usually operate on two or more frequencies, one for longer range and one for high-speed, in-room connections.
  19. I attend the local Rochester parkour gym (http://www.rochesterparkour.com/) on a weekly basis. I also tend to struggle to come up with topics for my physics blog posts. But today, I had a revelation: why not combine the two. So I introduce my new series, the physics of parkour. First up is the "top-out". A top-out is essentially a way to go from a hanging position on a ledge (a "cat"), to having your upper body above the ledge with your palms supporting you, without clambering up with your elbow in between. Here's a mock up of it: And a video (if you only want to watch the top-out, and not all the instruction, you can go to 5:12): It relies on three things: a solid footing, a good knee drive with the hanging leg, and of course maintaining a solid grip with your arms. When done properly, it requires a lot less upper body strength then you might imagine. For a brief overview, it consists of three parts: building upwards momentum with your legs, building a bit of forward (but mainly rotational) momentum with your arms (the reason why they play more into rotation more than anything will be discussed), and finally transitioning to the support position resting above your palms. First, and most important, is the legs. One is planted firmly, and the other is supposed to drive upwards, in order to build momentum which will later be transferred to the rest of your body. However, friction can be tricky: the tendency of your planted leg is to slip and slip, because most people will "paw" at the wall as if they were running up it. As we know, frictional force is proportional to normal force, so you actually want to kick/jab your foot into the wall, because this will allow it to stay in place. As you're doing this, you can drive your hanging leg up, generating some momentum. During this, you should also be pulling up/in with your hands. Simply, you want to counteract/overcome the force of your leg pushing away from the ledge, and also gather a bit more upwards momentum. However, simply due to the weaker nature of our arms, it won't contribute quite as much as our legs, which can be surprising. What is helpful, though, is the torque it creates on the body: while it is counteracting the linear momentum from our legs, it is working with the force from our legs to rotate our body over the lip, which is more beneficially, seeing as we right next to the wall to begin with. Now, with momentum built up from our knee drive and arms, and a slight rotation, our upper body will pop up and over the ledge, and rotate us into a position where we can easily re-position our hands to rest on our palms. From there, it is usually pretty easy to swing/climb up the rest of the way. But without proper training, this technique is very difficult, because people usually rely on their arms way too much. Yet again, it's an example of something made easier through physics.
  20. Physics of cat toys: make it a series
  21. the thumbnail is pretty good regardless, though
  22. Nah son, quantum computing. Now that's cray. Though because it isn't a binary based system it would require a fair bit of re-architecturing of modern operating processes (more than it would require otherwise)
  23. Nah i wanted my car to catch fire its cool
  24. I once read a book called "How Things Work", which featured analogies like this alongside a plentiful heaping of cartoon mammoths (mammi?). It was actually quite informative on things like this, though not overly technical.
  25. yeah society man. who needs it

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