Soviet lunar rocket concept : the UR-700 - pretty much kerbal !

[sgt_flyer]

Ok, here's a rocket i built upon the designs soviets created for an alternative to the N1 lunar rocket, the UR-700.

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the LK-700 lander was intended to make a direct moon landing, there was no separate lander (intended to reduce risks for the cosmonauts, as a moon orbital rendez-vous was deemed very dangerous. (a problem, and the cosmonauts in the lander would have been stuck there)

it featured several interesting designs, one of them being to put additional fuel tanks at the top of the boosters, those additional tanks where set to directly feed the core stage of the rocket. (crossfeed style, years before space-X falcon 9 heavy !)

the upper stage would have been made of a modified proton rocket first stage, with only 3 strap on tanks and engines instead of the proton's usual 6.

the moon landing was intended like this : the braking stage was used to slow down the lander to a speed of 30m/s at 4.3 km above the moon, was jettisoned, and the lander would then land by itself, using almost none of the lander's fuel for the landing.

here's the .craft file : http://www./download/iznq1oyxm5md428/UR-700.craft

a note of warning : the rocket is made of 986 parts at liftoff (slowed down my i5 to about 1/3rd of the normal game speed, with physics slider set to the max)

action groups :

key 1 : open the antenna (to use after the orbit has been reached)

key 2 : toggle the ladders

key 3 : toggle the lander's engines (not really needed)

key 8 : deploy the command pod parachutes (in case of abort)

key 9 : separate the command pod from the escape tower (in case of abort)

key 0 : toggle the gimbals on the booster's engines.

abort key : separate the command pod from the rocket, and fire the escape tower to clear the rocket (it also disable the command pod's torque, to prevent the ASAS from messing with the escape tower's movement).

Mission profile :

lift off at full thrust.

climb straight until 8000m.

at 8000m, start your G-turn with a smooth curve to reach 45° at 15000m. keep your 45° until the boosters are empty, and stage them.

you can then jettison the various fairings in order : first the escape tower with the conical fairing, then the transfer stage fairing, and last the upper stage's fairing.

continue your smooth g-turn to reach 30° at 20000m, 20° at 30000m, and 5° at 45000m. (the core stage will burn out during this part) once at 5° angle, keep burning at this angle until you reach your desired apoapsis for your mün transfer. once your apoapsis is good, jettison the upper stage (so it will burn up in the atmosphere, and circularize with the transfer stage).

once in orbit, make your mün transfer burn, and once your burn is done, you can drop the transfer stages. (the 3 tanks with engines around the braking stage)

when you arrive at mün, brake into orbit with the braking stage, then deorbit to land where you want. slow down with the braking stage until you are around 30m/s at 2500m above münar surface, and drop it. (the braking stage has an automatic fuel cut-off system when you stage it, so you can keep your thrust)

deploy your landing legs, and land

mün ascent : the landing legs platform will act as a launch platform : when you stage it, the CSM will 'fall' onto it, you can then increase your thrust for lift-off. fly straight up for a few hundred meters, then make your g-turn to get into mün orbit. (i usually set off to a 45° angle until i reach 5000m, then i burn to 0° until i get the apoapsis i want, and then coast and circularize)

once in mün orbit, make your transfer burn back to kerbin. once there, when you are deorbited, you can stage to eject the command pod from the service module. (the antenna's support will also be ejected to make way for the drogue)

note regarding the rocket : i took some liberties on the design, as the various informations we have on this rocket are mostly based on the concepts the soviets made for this rocket. notably, the payload in KSP is bigger compared to the design concept - but the rocket has an high enough part count as it is

also, i used winglets on the boosters for the rocket, although the rocket was supposed to use Grid fins (but those are not really doable in stock KSP - or at a really high part count )

- As always in KSP, have fun

Edited August 29, 2013 by sgt_flyer

[GusTurbo]

Totally insane and totally awesome. I would try this, but it will probably cause my i3 laptop to involuntarily shut down.

[Darth Lazarus]

it's so shiny

[iDan122]

Mine just blew up while ascending...

[sgt_flyer]

i'll retry it with 0.22 - but the lander's legs will have been swapped - i don't know if it's adversely affected the lander.

edit :

ok, i retried it (redownloaded the version i uploaded to be sure to test the same rocket ) and everything's worked fine (from start to the end)

mmh - i know i encountered some random unplanned dessassemblies in the past when loading directly on the pad (not only with this one, but with most of my near 1000 parts rockets), and those bugs disappeared by loading the rocket from the VAB instead of directly on the pad. also, i always have the physics delta time slider set to 0.03 (helps a lot with physics on those part heavy monsters )

also, don't forget to disable the gimbals on the outer boosters (key 0) - it helps a lot for diminishing the rocket's shakings

for the landing legs, the new legs kills a bit the lander's look, but it still works correctly (also, the new antenna dish changed the spacecraft look a bit - this antenna is huge compared to the old dish ).

Edited October 28, 2013 by sgt_flyer

[cannedcreamcorn]

the braking stage was used to slow down the lander to a speed of 30m/s at 4.3 km above the moon, was jettisoned, and the lander would then land by itself, using almost none of the lander's fuel for the landing.

That's how I've designed my landers lately. For Duna, the braking stage (a t-200 and a LV-909) gets me to around 100 m/s, deploy chutes, and then drop it at the last minute. I use very little fuel on the return stage so I have a nearly full load on touchdown. I plan a Gilly mission that uses the same design (minus chutes of course) so that would be closer to the mission profile that the Soviets would have used.

It's cool to see that I came up with a design solution that someone planned to do in real life

[sgt_flyer]

well personally, when i read about the UR-700 concept (notably the fuel crossfeed system idea they came up with for the first stage), i found that it was a really advanced idea for it's time (i think the UR-700 crossfeed way is even safer than SpaceX planned crossfeed systems - with the tank to be drained 'separate' from the booster's main tank. (actually, on the UR-700 concept, they had 2 sets of 3 boosters : 1 set with an additional separate Lox tank at the top, and 1 set with an additional separate liquid fuel tank at the top) - thus limiting the 'plumbing' necessary to bring the fuel and oxygen from the boosters to the core stage.