closette

You killed Kermans! You bastards!

You mean this chart? http://kerbalspaceprogram.com/forum/showthread.php/6664-Mini-challenge-max-altitude-with-this-supplied-spacecraft?p=100912&viewfull=1#post100912

Terminal speed and max Q are not the same thing at all. I think the OP was using the result that the most efficient ascent speed (at a given altitude) happens to be equal in magnitude to the local terminal speed, i.e. when the drag force and gravitational force are equal in magnitude. Unlike in the real world, if you follow the optimal ascent speed vs. altitude, the instant of "max Q" (maximum drag force) occurs soon after launch for most spacecraft in KSP, due to the weird mass-dependence in the drag model. As the rocket ascends, it not only encounters thinner air but also loses mass as fuel is used up. Even though the drag is proportional to speed-squared, those two effects more than offset that. (For my Goddard Challenge rocket when following this fuel-efficient ascent profile, max Q occurred at a mere 250 m altitude on the way up while at full thrust, and at about 8000 m when falling back down from 33000 m). Most craft will experience the greatest effect of drag (i.e. drag force per unit mass) on descent from orbit, around the 8-12km altitude mark, when their re-entry speeds get slowed from a few thousand m/s down to a few hundred very quickly.

See http://kerbalspaceprogram.com/forum/showthread.php/14273-Smallest-orbit

One small issue is that KSP currently displays apo- and periapsis as altitudes above the planet's surface, not as distances "r" from the planet's center. However, I believe that the orbital elements of spacecraft are in the persistent.sfs file so you can pull them from there to get the planet's mass, and then compare with the displayed apses values to get the body radius.

I wasn\'t trying the (rather pointless as described) challenge - I was just verifying that the edge of the atmosphere is where it has been since before version 0.16. Time to move on...

I just did this and verified a pre-0.16 result reported here: http://kerbalspaceprogram.com/forum/index.php?topic=5623.msg92331#msg92331 that the atmosphere ends at 69077.5 m above sea level. Screenshot attached to show x5 warp is possible below 69200 m. (I didn\'t hit F1 fast enough to catch it right after 69077.5 m, but you can try for yourself).

@PLB: Not sure where you get that from. 70 km is outside Kerbin\'s atmosphere so the drag is non-existent there, not 'least'. Try this experiment: establish a 72x72km orbit (or close thereto), then gradually retrofire at apoapsis to bring periapsis down to, say, 68km. Time-warp and note the altitude that you are thrown back into 1x speed. That\'s where Kerbin\'s atmosphere 'ends'.

Well I realize that everyone has moved on to 0.16 which doesn\'t work with the parts provided, but I fired up my precious copy of 0.15 and with a more carefully tuned strategy achieved: 1. 202.92 kg remaining to get into a 3.2x3.8km orbit (first screenshot attached, with the MunArch in the background). This time, after lowering Pe while far away, I was more careful in changing from hyperbolic to circular orbit. I took two orbits to do it so that I could have engines firing as close to periapsis as possible. This time I also took care to start the burn slightly before periapsis such that the periapsis point would always remain just in front of the spacecraft. If it advanced too far in front, I would stop firing briefly and coast a little. 2. Landed with 115.0 kg remaining (second screenshot attached). This would make a great separate challenge. I did some research on terminal descent onto the Moon from lunar orbit - plenty of papers but very few show the actual throttle profiles. But rather than 'stop, then drop', they seem to employ a 100% throttle braking burn to kill off most but not all of horizontal speed, then a slowly decreasing throttle for a gravity turn, possibly going to zero, followed by a brief throttle-up burst just before the vertical landing. This is what I did, and despite a 'bounce' on landing I got away with an intact spacecraft. I learned a lot from this challenge - looking forward to similar ones in 0.16 once the LFT fuel bug is fixed.

Not to mention the whole 'tilt over to 270 degrees heading' thing, which I\'ve seen a few people post that they do to get into orbit. There\'s a reason why KSC (in game and in Florida) are on the east coasts of their continents. Launching eastwards gives you a free boost in that direction due to the planet\'s rotation - 174.5 m/s in the case of Kerbin. In the game, click the 'Surface' indicator on the Navball while sitting on the launch pad and you\'ll see what your 'orbital' velocity is relative to Kerbin\'s center. Very few satellites are launched into a retrograde orbit (see http://en.wikipedia.org/wiki/Artificial_satellites_in_retrograde_orbit) since it would be an enormous waste of fuel to cancel out Earth\'s rotation.

Thanks for the kind words (this challenge was a team effort) and for revisiting the challenge - it\'s been ongoing in some form since 1919! http://en.wikipedia.org/wiki/Goddard_problem. I\'ve only just installed 0.16 (Mac users had to wait) but it certainly sounds like a fuel problem, and not a change to the atmospheric drag model which I would be very interested in! I\'ll check it out later on but it sounds like a 0.16.1 revision should bring the challenge back to 'normal' and restore honor and dignity to the leaderboard...

Hairline receding? How do you know without a 'before' picture? I guess we all have our own 'background stories' for them, which is a good reason for the developers to leave some things undefined. The fan fiction and role-playing forums seem to have taken off based on pure speculation and imagination filling in the blanks, which is fine (just not my thing). So I was surprised that the developers recently gave Kerbals a voice on video, and allowed us to see them without space suits in the 0.16 VAB, but I guess that more details will slowly be filled in as the game progresses towards crew selection. Yes, eventually having some flexibility with Kerbals\' features and names for users to choose, without explicitly acknowledging a gender binary, seems like a good way to go.

Personally, I would prefer to keep Kerbals unisexual (or asexual?), to keep focus on the space program, which I find a safe haven from imposition of gender stereotypes. (I wasn\'t too keen on that comic\'s first female character being referred to as 'fresh meat', by the way). In my own imagination, the Kerbals are grafted and grown like plants and later develop limbs the way that tadpoles develop into frogs. They are cute the way they are, and although I use male pronouns to describe them I don\'t feel there\'s a great need to add another gender (and if so, why stop at just two?). Weird for me to be defending the status quo. though!

Congratulations on reaching orbit. The free version you are using (0.13.3) has fewer features and does not limit fps as far as I know. The paid version has many more features which might well end up producing a slower fps overall, depending on your system. I keep both versions (and a couple of intermediate ones) on my laptop\'s hard drive depending on whether I want to show a quick demo or do something more in-depth with all the features. My advice - feel free to ignore - is to play the free version up to being able to complete a Mun mission, before going for the more fully featured version, which by then you will both want and appreciate all the more.

Well I guess I\'m one of the 'impatient' crowd as well (although I am a Mac user and have to wait for the Patcher to be fixed to even get 0.16, grrr...). If x2 warp is so bad, replace it with x3 Practically, leaving the game to run while you go and make tea / check email / whatever isn\'t the best solution since we\'ll either forget to check back in time or will be constantly checking 'are they there yet?'. Aerobraking is one of the cool features of the game and it sounds like it just got a bit more tedious in 0.16.