Jarnis

So, Bill kept wanting to fly over and over again and KSP was rapidly running out of boosters (accidents, Jeb doing his thing and so on...). Those things cost some real money and with the whole thing thrown away every time, Bill just couldn't get a rocket to fly again and again... Then someone found an interesting video from some competing Space Business... I of course mean this one; "Hey, we can do that, can't we?" Bill could immediately see the benefit. If you just landed the stages back to KSC under rocket power, they could be refueled for another go in no time. Bill could get to fly a rocket every week! "Landing a rocket stage back on launchpad. I mean, how hard can that be?" Now at first I thought such a mission profile would not work in KSP because you can't be piloting two things at once - once you ditch first stage, you need to be flying the upper stage to orbit while the first stage falls down. But I really wanted to see how it would look like when a massive first stage simply turns around and tries to fly back to the pad. After bit of experimentation I saw a way to run a suitably steep trajectory and get the upper stage high enough before the first stage re-entered and got wiped out and... After some half-dozen dry runs to get the timings of everything down... Presenting my humble attempt to re-enact Falcon 9R mission profile in KSP: It really works! And the fuel required for stage landing is almost nothing. Sure, payload mass will be lower per launch but stage re-usability would make it worthwhile. Save for the potentially iffy bit of heat shielding the second stage properly so it survives re-entry intact, it should work. Can't wait for SpaceX to try it for the first time (starting with Stage 1 recovery without legs to a kinda-soft ocean landing at some point later this year). Probe bodies and RCS systems in all stages to keep them controllable. All stock except for MechJeb. Even SpaceX will use computer programs to control missions and landing stages with almost no fuel margin is not something you'll be able to fly manually anyway. Payload is obviously tiny but I can't see why this couldn't be scaled up some more.

Real men only do round trips... ...and those are mighty hard without docking. Duna is possible without (using 1-man pod), some of the others probably not. I have a 3-man pod version for Joolian moons all specced and ready to go with several test flights done around Kerbin but the docking addon required isn't yet 0.17 compatible...

Not certain this can be done. The velocity you will have after passing Mun, no matter the trajectory, will be FAR too fast for Minimus to slingshot you back towards Kerbin. Minimus gravity well is just too small to do what you suggest. Well, I guess in theory you could have a trajectory from Kerbin towards Minimus that just barely enters Mun SOI and then just barely makes it to Minimus but even then... if the return path should actually re-enter... not sure if possible. Any "real" slingshot past Mun (add any meaningful amount of speed) would put you far past of what Minimus could then bend back towards Kerbin. Kerbin -> Mun slingshot towards Minimus -> Slingshot out of Kerbin influence to interplanetary trajectory would be doable. Somewhat complicated to time but doable.

I just wish people showing off the game would be less terrible in it. They make "game journalists" look bad. I mean neither really even showed how a "proper" rocket would fly (and get to orbit) - okay, so they were just giving it a quick spin "first impressions" but all they really showed is that they had no clue how rockets work in real life. At all.

That is the most epic thing ever... I sense lots of Kerbal-based experimentation involving rocket engines in the future... with poor test subjects ending in unrecoverable orbits in deep space...

More struts. Also use 1M decouplers, they are stronger.

...so who took off the helmet to lick a rock and then dropped it because it was hard to breathe on the Mun? (If you don\'t know what I\'m talking about, watch the 'Mun surface' KSP title screen for a while)

After further testing I\'m fairly certain that this is caused by two factors; - 3m decoupler is not as 'firm' as the 1m one, it lets parts shuffle around more (which can then be amplified to a rocket snapping in two) - Massive 3m liquid engines being gimballed is... problematic. Even a tiny movement of such a massive engine jerks the ship around. I\'m sure if we had also a non-gimballed large 3m engine and would use that with some fins for steering instead, things would work somewhat better. Still, you can work around these issues with struts. Lots of struts. Also make sure you do not overdo the first stage; wobble gets worse if you have 'too much' thrust and start hitting the atmospheric drag big time at low altitudes. Additionally, never ever start the automated gravity turn before 20km or so; You want the first stage gone before you start turning...

Try 'go full orbit around Minimus from a landed craft using just a jetpack'. Doable if you are careful with the jetpack fuel use. Forgot to take screenies but it definitely can be done... 8)

Well, I got the 3M parts to behave almost acceptably by using the 1M decouplers (3M decoupler only for 3-person pod attachment) and struts. LOTS of struts. 8 struts between each stages over the engine, additional struts between 1st and 2nd stage and tons of cross-struts between side-by-side 3M tanks of first stage. Still wobbly, but no longer gets ripped apart even with 400ton+ takeoff weights (my 3M-based test setup for future interplanetary missions) 3M decoupler is problematic tho. 1M decoupler also is very weak for separating 3M parts which are so much heavier, so you have to stage carefully. Also radial decouplers are still fairly weak. Easy to cause unintended collisions... Edit: With some serious tinkering managed to get 730 ton monster off the pad... had to do lots of little tweaks to prevent it from tearing into bits... but in the end I have 73 tons of rocket on 180km circular orbit, ready to insert to an interplanetary trajectory. This is fairly close to the maximum as long as we have this tower; the rocket is already twice as high as the launch tower and can\'t fit more stuff radially without hitting the tower

Here is the contraption that got the lander there... Both SRBs *and* LFE-based 2nd strap-ons... 3M parts are just so damn heavy. Smallest 3M LF Tank weighs some like 8x as much as the tiny 1M LF Tank... I guess if the rest of the rocket was also built out of 3M parts (so something like 5-7 3M Liquid Engines at the first stage) it wouldn\'t be such of an issue but such design just tears itself apart...

It took quite many failed rocket designs, but I finally managed to get a 3-man lander on the Mun. The new parts are really wobbly. It\'s like flying with NovaPunch parts... Only way I could get a sane rocket to hold together with this thing at the top was to use 1M parts for the second stage and for 6x LFE boosters around a 3M first stage... ridiculously large rocket, weight about 250 tons. Landing mass on the Mun 17.7 tons... I think the new parts still need some work Edit: And I got them back home safely as well. Landing wasn\'t quite on target (ran out of fuel to properly put it at KSC) but any landing you can walk away from is a good one, right?

The fact that you can do this with fairly small rockets is all about the efficient 'vacuum engine' (small LFE). You do not need massive thrust for anything once you are in orbit. Heck, a single small LFE could push any kind of mega-stack of fuel - burns would take long, but it doesn\'t really matter.

Fairly trivial with MechJeb and no need for exotic modding or ion engines or any of that junk. Just plain old Liquid Fuel Tanks and engines. I gave it a shot with my generic satellite deployment rocket (minus the satellite that usually sits on top with Mk2 chute) and managed to do it on the first try with about 10% fuel left at the last stage tank. Looked tad hairy when burning back to Kerbin and the automatic Trans system got confused by math inaccuracies but I managed to manually adjust the trajectory for a *perfect* Kerbin encounter at '0km periapsis'. Had I had more fuel left over, I might have tried very low level aerobraking and settling back to Kerbin orbit but decided not to risk it considering I had roughly nothing left. See attached image for the rocket used. Mission total time 118d 14h and no, I didn\'t wait for the hyphotetical 7 orbits around Kerbol. Didn\'t take screenshots along the way because I honestly didn\'t expect to succeed on first try. If needed, I guess I can re-fly this tomorrow * First Stage: four radially mounted 3xLFT + LFE boosters + 4x SRB radially mounted for initial kick off the pad. Takes everything to ~60km apogee, just shy of 75km orbit insertion. * Second (core) stage: 4xLFT + steerable LFE finalizes the orbit and does Kerbin escape burn. with about 1 tank left over. Kerbin escape was done with good old 'eyeball mk1' burn with MechJeb holding prograde heading. Leftover of this stage is used for initial braking towards 7M km periapsis around Kerbol and the core stage is then ditched. * Third (upper) stage: 1xLFT + small LFE finalizes the transit to Kerbol orbit at 7M km. In my run it ran dry about 50m/s before circular 7M km orbit. * Fourth (return) stage: 1xhalf-sized LFT + small LFE does the final adjustments for the required orbit and then the burn back to Kerbin. Atmosphere and parachute handle the braking. About 12.3G peak on re-entry, Jeb didn\'t even flinch... Only non-standard parts are the pod decoupler and some cosmetic solar panels. Oh, and MechJeb, of course. All hail MechJeb for super accurate burns and required instrumentation.

Must say it was damn cool when bit after clearing the pad they noted the pitchover kick and start of the gravity turn. 'Hey, that worked just like in Kerbal Space Program...'

Bit over 3 days from now if I recall right. Lots of in-orbit tests and some maneuvering around the station first.

Solar arrays deployed. In orbit. Launch success.

http://www.nasa.gov/externalflash/spacex/index.html - dry NASA version 30min to go.

Not Kerbal-failed. Aborted right after main engine ignition, before released from the pad. I guess next window is on Tuesday.

SpaceX webcast up. Also Nasa TV Stream up http://www.spacex.com/webcast/ http://www.nasa.gov/multimedia/nasatv/index.html Space X fullscreen on main monitor showing pre-launch stuff, Nasa TV fullscreen on 2nd monitor showing just live feed from the pad = epic

SpaceX webcast starting in a bit. Launch in about 50 minutes. http://www.spacex.com/webcast/

...or just apply MechJeb and concentrate on navigating rather than piloting. For most common tasks it does a fine job while still requiring you to actually decide what you are trying to do. I mean, real astronauts would pretty much do the same thing; Instructing an onboard computer to execute required maneuvers and monitoring how things are going, always staying on top of 'what is supposed to be happening' and ready to take manual control *if* what you are seeing the MechJeb do isn\'t what you are expecting... Once you have succeeded in what you were trying to do with MechJeb, you can start playing super ace space jockey and do it 'by hand'.

Been there, done that. http://kerbalspaceprogram.com/forum/index.php?topic=2730.msg28204#msg28204 My best is 234.5G (fully stock parts) and it didn\'t even win that time around. Best one was 273.8Gs using stock parts. So you young padawans still have much to learn...

This mostly demonstrates the ridiculous weight of the decoupler more than anything else... in reality the mechanism for separating two stages should be just a tiny fraction of the total stage mass. ...and we all know in rockets every gram that isn\'t fuel is VERY VERY BAD and should be removed if at all possible.

3km orbit at the moment, hasn\'t hit anything yet... (equator) but some peaks are frighteningly close. Edit: Just went above a peak so close I could count the individual rocks at 3120m