tavert

I'm currently in grad school for Mechanical Engineering, but have worked in the aerospace industry before.

Some cool pictures found on Elon Musk's twitter, for anyone who hasn't seen these: Landing leg, and what looks to be an aerodynamic fairing for when it's retracted http://t.co/H49TSS2CYl Payload fairing in an enormous vacuum chamber, closed http://t.co/BLOTThWFvw and open http://t.co/2zkLi4ON0s Does the shape of the leg fairing remind anyone of an elongated Star Trek logo?

They have Soyuz lifeboats docked ready to come home if they need to. Constellation was a many-billions-of-dollars organizational joke/nightmare and cancelling it was the right move. Even it had been funded properly by Congress from the start it wouldn't be ready yet. Focusing on COTS and shaking up the way the aerospace industry does things has been surprisingly fruitful despite the relatively low level of investment so far.

I believe SpaceX is an exception, it sounds as though they do actually use Linux on their flight computers, but in a multiple-redundancy voting system: http://www.aviationweek.com/Blogs.aspx?plckBlogId=Blog%3a04ce340e-4b63-4d23-9695-d49ab661f385&plckPostId=Blog%3a04ce340e-4b63-4d23-9695-d49ab661f385Post%3aa8b87703-93f9-4cdf-885f-9429605e14df Dunno if calling Linux a "commercial" OS is quite fair, it does have lots of uses in embedded systems and such, but it's also a lot more general-purpose than it needs to be for those tasks, and can't do all of them due to the issues you mentioned.

I certainly did, anyway. Ah well, hazards of guessing randomly at what might work and submitting first.

I think once you're out of fuel your hyperbolic trajectory will maintain a constant v_inf, since v_inf^2 equals twice the specific orbital energy. The periapsis speed is different from v_inf. If you want to calculate periapsis speed then you first have to solve vis-viva for SMA: v^2 = mu*(2/r - 1/SMA), so SMA = 1 / (2/r - v^2/mu). Then plug in periapsis plus radius of the body for r to get v_peri.

The main guidance computers are in Zvezda, evidently they're ESA-designed: http://www.esa.int/For_Media/Press_Releases/International_Space_Station_docks_successfully_with_Zvezda_module GNC computers, at least in these established programs with so much legacy technology to utilize, aren't running something we would recognize as an OS, it's very specialized real-time stuff. Many of the Russian spacecraft use ancient analog computers, or simple digital I/O layers on top of the analog processor. They didn't replace these on Soyuz until 2 or 3 years ago: http://www.computer-museum.ru/english/argon16.htm Edit: My bad, the Argon flight computer itself is digital, but interfaced many separate analog subsystems until the TMA-M revision: http://spectrum.ieee.org/aerospace/space-flight/a-digital-soyuz

Alright, nearly 6 minutes of burn time and over 10 km/s delta-V expended (with some very fast-moving drop tanks following me, also on escape trajectories), total distance traveled 2,502,322 meters. Total liquid fuel + oxidizer + solid fuel on pad was 49997. http://imgur.com/a/u7mwx#0 I might try again with an aerosparagus design, building for this challenge is a nice way of demonstrating the relationship between Isp and burn time at a given TWR.

250 tons of fuel, eh? Or 375 of SRB's... I've got some crazy laggy bundles of various things (probably my most Kerbal rocket yet) trying to maximize total burn time, no idea whether that'll be optimal or not. Hard even for MechJeb to control, that's for sure. Can't wait to see what crazy number you got, if you're waiting to share it with us.

Very nice lump, told you SRB's are useful. You should put landing gear and parachutes on that bad boy and try a Mun round trip. I'll have to re-evaluate aerospikes on my designs... I had refined things to 4500 liquid fuel, 3 T30's, 2 LV-N's, and 4 SRB's, aerospikes might cut enough fuel off that to be worth the extra quarter ton of engine mass.

Guess you'll be out of town so might not answer for a while, but I'm hoping you consider this design more acceptable: http://imgur.com/a/gfq3M#0 Some cubic struts used for central structure and to mount the nose gear (both horizontal and vertical), no real clipping. I could move the rear landing gear and front winglets if you're super strict about the slightest bit of overlap on any parts. I'm going out of my way to try this with only one jet engine, to the point of having no real fuselage here, only side tanks.

Yeah, I predicted you wouldn't like it in my post a couple days ago - "I don't think the OP will like it much, since I resolved my engine difficulties by using cubic struts to clip an LV-N into the jet." Also, Mechjeb... "I'll take MechJeb off, it's just here for weight and delta-V stats and preliminary test flights."

Difference of opinion then. There is some practical design limit of laying out tanks and such (which you could circumvent while remaining within the letter of the rule here by making some spindly strut-structure thing where all tanks are round-8's and all intakes are attached to those round-8's), but how they're attached seems completely arbitrary to me with respect to the mechanics of how the intakes work. Anyway, for everyone's sake I'll try to shut up about it and just fly the plane.

Mechanically the same, aesthetically different. If you need a bi-coupler you're paying a penalty, but if you lay out your tanks differently you're not. Or for that matter you can use cubic struts to put as many as you want in a large space, no clipping required and not much of a stack there. The jets are just plain overpowered unless you say maximum N intakes per engine, for your choice of small N.

I think we're having a semantic disagreement about the word stacking. As far as game mechanics go, having multiple intakes per engine works basically the same way regardless of how or where you attach them (as long as they're all pointed forward). The only thing that really matters is the number (and type) of intakes per engine. Anyone using multiple intakes per engine is therefore "blatantly exploiting a broken game mechanic and clearly cheating," whether those intakes are attached in a compact way using cubic struts or otherwise. Everyone in this challenge so far has stacked intakes with multiple per engine, even if we have to go out of our way to make our planes a little heavier or oddly-shaped to do so. "Stacking" is not a true/false binary thing, it's a scale defined by a ratio. There are plenty of "tweak one or two numbers" quick fixes that could be made to nerf the jets to varying degrees, without modifying the underlying game mechanics at all - increasing intake mass, reducing jet thrust at high speeds, etc. These would be quick changes to make, but wouldn't the devs' time be more productively spent completely replacing screwy mechanics like the aerodynamic/drag model or the way intakes and jets work? From the sound of things, game balance in terms of part performance isn't really a priority at the moment anyway. Here's my plane, still need to fly the whole mission manually (I'll take MechJeb off, it's just here for weight and delta-V stats and preliminary test flights) and add some Mun-landing gear on the tail: http://i.imgur.com/VgNkMUs.jpg It gets to orbit with about 3800 m/s delta-V left, should need about 3/4 of that to get to and from the Mun. The nuclear engine is clipped inside the jet without using the debug menu. I place a cubic struts radially on the bottom of the capsule as centered as I can get it. Then mount the nuclear engine on the cubic strut. Place the jet fuel tank on the back of the engine, then move it to the inline attach point on the capsule.

Nevermind on rearranging fuel, how I had it worked well enough. Here's my entry, 9608 km. http://imgur.com/a/QEu6W#0 Almost to the Mun's orbit before fuel ran out, not quite. Full throttle, all of 1.5 kN for an hour.

So something less than 1663 K for you, depending on your timing in taking that shot.

Let the silly rule-bending (or perfectly obeying rules that don't take into account parts that weren't around in September) commence! I'm sitting in 4x warp at 7.5 Mm with 30 units of fuel still left. Thinking of rearranging fuel a little to get even more silliness.

MechJeb2's interplanetary maneuver planner gets closest. It does the transfer burn in the ecliptic, but it chooses how much delta-V to use for that burn by minimizing the actual closest approach distance taking the eccentricity and inclination of the target's orbit into account. If you don't happen to get closest your destination when it is at its AN or DN, then you will miss it. However the "fine-tune closest approach" option in the MechJeb2 maneuver planner uses a real Lambert solver. It fixes the time of closest approach to be the same as the time of closest approach of the current orbit (kind of an arbitrary decision, but done so the minimization of delta-V is over a single variable) -- the in-ecliptic transfer, then chooses when to place a correction maneuver to minimize the delta-V that achieves an intercept.

The densities of these real-life substances depend highly on what temperature and pressure you're storing them at. You're quoting a single number for each chemical which likely does not correspond to typical storage conditions in rocket tanks.

It's in the part.cfg file under velocityCurve, the max surface speed at which the turbojet generates any thrust is 2400 m/s. If you somehow had infinite intakes with zero drag so you could get up to this speed purely on jets at the very top of the atmosphere (69078 m), your orbital speed would then be 2594.6 m/s (flying east). Using planet.determineOrbit from https://github.com/numerobis/KSP-scripts, that would give an orbit of 577738 by 69078 m. You're not escaping Kerbin or hitting the Mun's SOI with that. Would be interesting to run the numbers for Laythe though, see if getting back into a Jool orbit only on jets is possible...

I did read your rules, as evidenced by me asking for clarification on several of them. I'm not arguing against you, you don't have an absolute limit of a specific number of intakes per engine, you said you can put as many as you want as long as they're attached in a reasonable manner. I was arguing against whatisthisidonteven, who was being much more absolutist about intakes being broken so stacking them is an exploit and indicative of a lack of skill.

Cool rockets Anglave, nicely done! You do realize this is a 7-month-old thread though, right?

If you only consider the gravitational forces from a single body at a time like KSP does, then Oberth effect in different positions around the orbit is the same. The potential energy of your solar orbit is almost the same on the day side versus the night side of a planet, so there's not much solar Oberth difference. But ejecting from a planetary orbit in the planet's prograde direction is the best way to transfer to planets further out, and ejecting in the planet's retrograde direction is the best way to transfer to planets closer in.

You can always switch craft and warp to pass the time in something else. Kerbal Alarm Clock is really useful for this. The orbital speeds aren't much different between 30 km and just scraping the mountains, but you will lose more speed to gravity in getting up to 30 km. Compare your speed when you shut off the engines to when you get to apoapsis. Burning horizontal as soon as possible to get a high periapsis before your apoapsis reaches your target altitude will also reduce your gravity losses.