KerPollo 8 Apollo Replica

[thunderstar]

i have been trying to recreate a fully functional saturn V in a while and i recently finished it, its modded craft btw i think it looks nice, i tried my best to make it look like the real thing and also being capable of going to the mun or even beyond, i have the subassembly of the ship thats only the 3 stages without any command module as well i have a entire ship, the subassembly only uses procedural fairings, stretchy tanks,KW and AIES the full ship, with CSM and lander,uses ALCOR for the lander module i know in needs a lot of mods but its easy to fly, just like any simple rocket without needing action groups

second stage, i tried using 5 engines here but it tended to explode after staging so i used only 1 griffon xx,the engine in the picture, problem is solved now

third stage, ignited twice, for orbit and TMI, has enough fuel to enter mun orbit without using the CSM fuel

Edited November 22, 2013 by thunderstar

[Majorjim!]

Hello John FX. Im glad you redid the lander. Looks much better now. I really love Apollo craft. We should have a thread just for them! So us Apollo lovers can discuss

bits a bobs.

Keep up the good work mate.

MJ

[John FX]

Hello John FX. Im glad you redid the lander. Looks much better now. I really love Apollo craft. We should have a thread just for them! So us Apollo lovers can discuss

bits a bobs.

Keep up the good work mate.

MJ

Thank you. I`ve been reducing size and I`m starting to hit limits. You should see the rover I fitted into that thing!

That is a very good idea, a thread to discuss all things Apollo but I`d like it to be more kerbaly (kerbally?) than a heavy tech re-evaluation of the original flight. Along the lines of which stock parts seem designed to go on an Apollo flight. The three man pod being an obvious one or building techniques (although there already is an excellent building techniques thread)

bits n bobs sounds like a very good topic.

Nice rocket you have there thunderstar. It seems to have a bit too much fuel though if you can orbit Mun still using stage 3. I have made mine have just enough so stage 2 cannot even orbit on rails and after burning for Mun on a FRT you should have maybe 50Dv left in stage 3. Dropping fairings and stage 3 at this point lets them burn up again back on kerbin and the CM has just enough fuel to adjust for a closer munar encounter, orbit and burn back for kerbin on a path that will hit atmosphere and have about 10-20Dv left. The new lander has about 1100Dv so you have plenty spare for landing just where you want and the ascent module has 965 which is enough to get into orbit and rendezvous with the CM.

Have you any pictures of your lander and rover?

Edited November 22, 2013 by John FX

[John FX]

Kerpollo 7 Rover Teaser.

[Bluegobln]

Not sure if maybe someone mentioned this somewhere but if you turn your engine off (right click or by setting it up in the VAB) you can max your throttle then turn it back on and blast off at maximum per your preference, rather than burning up the previous stage's fuel supply while on the ground and using the staging to accomplish it.

[John FX]

That is a very good point. I shall be doing that from now on!

[John FX]

Kerpollo 7 Lifter Teaser.

Edited December 15, 2013 by John FX

[John FX]

A little news for those interested, I have seen that Mulbin has decided to break the `stock mould` and will be releasing a KOS script to launch Munbug XII and after seeing his video and downloading KOS, I have decided to do the same. This will be for the christmas release of KerPollo 7 which will be able to at a minimum, launch the craft, activating all stages and ullage engines, releasing the escape tower and getting into orbit. I only downloaded KOS about 30 hours ago but I have got KerPollo 6P (prototype) to orbit, I just need now to make it a better orbit with more circularity.

It will be the first step in making a suite of programs to launch (easy so far), burn for Mun(hard), orbit mun(medium), land(hard), orbit(easy) and return from Mun(easy).

/On a side note, removing mods for bugtesting KOS I realised I was usung KIDS which made all my fuel levels far too high so part of KerPollo 7 will be, again, refining fuel levels. Properly this time...

//Now I am wondering about all the craft I designed after I forgot I installed KIDS...

[John FX]

Update : KOS is awesome.

After a few days of learning curve, I now have a program for the craft which reliably launches the craft, throttles down at terminal velocity, starts a gravity turn at 6km, throttles up at 8km (thinking about leaving throttle at 100% as the F1 could not adjust throttle, any feedback?), shuts down the center engine when 25% fuel remains in stage 1, activates the ullage motors just prior to the end of stage 1 which separates the two stages (along with retrorockets in stage 1) and ignites stage 2 when clear of stage 1. stage 2 also shuts down the center engine at 25%, activates retrorockets and ullage engines just prior to stage 2 shutdown with stage 3 igniting just after separation. Stage 3 does orbital corrections and then searches for the mun and creates a FRT node with a munar periapsis usually of around 40-50Km (sometimes as low at 8, sometimes as high as 59 so far) and also executes the burn for mun. Then the program ejects fairings, releases the CM and gives control to the player for a few minutes so they can dock the CM to the Lander. Stage 3 automatically ejects to avoid unwanted forces. This is what is working and is stable so far. I am working on Munar capture and orbit circularisation ATM.

Fun fact about the Kerpollo 7 lander : If you find yourself upside down, don`t worry, just raise your legs and use the torque of your craft to pull you the right way up! Then activate SAS and quickly put down the landing legs. A small hop and a mid air wiggle later and you are right as rain and most of the time nothing broke off!

[Deathsoul097]

Now make this for RSS! lol

[John FX]

Now make this for RSS! lol

Why would you want a news feed?

Seriously, the code already could be used for RSS if you mean real solar system but the craft could not. KerPollo is more stock than it looks. The Cm and lander al completely stock, the lifter only uses stock engines and it`s purely the tanks and fairings that are modded.

The program already has variables for turn start, turn end and so forth so it could be used on any planet with not much fiddling.

I think your desire to see apollo in RSS will have to be satisfied with whatever you make yourself though. I`d love to see whatever you make!

[John FX]

KOS Update : I have finished the main programs. I have split the main program into parts. One that launches the craft, one that searches for a node that will intercept the mun and creates a FRT node with a munar periapsis usually of around 10-50Km and also executes the burn for mun. Then the program ejects fairings, releases the CM and gives control to the player for a few minutes so they can dock the CM to the Lander. Stage 3 automatically ejects to avoid unwanted forces. Then the program then warps to Mun SOI. On entering Mun SOI Pe is adjusted and a capture burn is executed. On the next orbit the program does a circularising burn and once in an orbit between 10-12Km the program ends to allow the user to perform the mun mission.

Then I plan to have the lander program run on the KOS unit in the lander to perform the descent. After executing the mission on Mun the launch and rendezvous programs will be run which will then enable the user to dock with the CM.

The home portion of the main program suite is written which finds the right time to burn by using the brute force method of checking when Kerbin is directly above then burning for 290Dv 930 seconds later. The craft then activates AG6 (don`t press it in space you will have no Dv!) at 7000m to separate the CM and deploy parachutes. The science module will parachute by itself and land close to the reentry capsule. The manned capsule should land at <7m/s.

Next I have to write the descent module (might not be very easy.), ascent module(should be easy, may reuse some of the main ascent module) and rendezvous module (not going to be easy)

Currently, the craft will take you from the launchpad to the Mun and put you in a 10-12k orbit and then let you do the mun mission manually. After you have returned from the surface, transferred crew, dumped the ascent module and run the return program it will take you home. I have not used any reference material or known formula to make this KerPollo automatic pilot. Everything just blindly does what the boffins said it needed to at the time the boffins said it needed to happen.

I`ve decided not to include Mechjeb or Remotetech in the next release as they are so easy to add yourself if you want to and I am trying to keep my install as clean as possible for bugtracing.

Here is a lander update/teaser.

KOS executing first stage separation...

Edited December 10, 2013 by John FX

[John FX]

KOS Update : I have been doing some efficiency improvements mainly on approach to Mun and bugfinding, for example there were two places where the program would think it had found the correct burn point for the mun, in some cases burns were not being done right etc

I have been reducing the size of the lander and tweaking things to allow a smaller width stage 3 and checking how well the rover can get out from under the lander (not bad) and thinking about ways to improve the A.L.S.E.P.

I have changed the chutes to realchutes just because they are cool.

Anyone have an opinion on that or features they would like to see included in KerPollo?

Edited December 17, 2013 by John FX

[John FX]

0.23 KerPollo 7 *Complete Rebuild* Kerpollo 7 Saturn V, Realistic Eagle, 2 Kerbal Rover, CM, MM, A.L.S.E.P, Ullage Motors, RetroRockets, engine cutout

May I present my Apollo replica `Kerpollo`. It is currently Kerpollo 7. The first Kerpollo was made for `doing it Apollo style`. I have since tweaked it just a little bit. You will need procedural fairings and stretchy tanks for the launcher and realchutes and KOS for the rest.

Action Groups

1 after landing setup operations (lights on, ladder down, drop rover and A.L.S.E.P)

4 Open Lander Kos Terminal

5 Open Command Module (launch) KOS Terminal

6 Separate Command Module and Activate Parachutes (Warning, for final landing ONLY)

8 Shutdown Stage 2 Center Engine

9 Shutdown Stage 1 Center Engine.

0 Toggle Stage 1 Gimbal

Spaceport link : http://kerbalspaceprogram.com/kerpollo-7/

Lock gimball for takeoff. Your flight profile should be to aim high and use the power of the first stage to give you a nice high apoapsis and a lead time until Ap of about 55s. You can then use this time to gain some horizontal speed with the second stage while trying to keep as much vertical speed as you can. you should level off before the end of the second stage with an Ap of 55Km At the end of the second stage you should have an Ap of about 60Km which is then about 90s away. Carry on burning horizontally until your Ap reaches 80Km. your Pe should then be about 50Km and including the circularization burn you should have used about 300m/s of your third stage leaving you with about 950m/s if you are careful. If flown using a FRT then no debris will be left except for the portion of the descent stage left on the Munar surface, a rover, the A.L.S.E.P and a flag if you planted one.

I advise to land using the efficient method for low TWR craft from Kosmo-not. (set your Pe to 5km though as the Mun is more lumpy now, start about 58 Km from your chosen landing spot)

quicksave then use action group 1 to set up and then have fun with the landing strut/righting mechanism to get the rover on its wheels without tipping the lander.

Explore and have fun.

KOS USAGE

press 5 to bring up the terminal.

copy tomun from 0.

run tomun.

will get you to Munar orbit.

press 5

copy home from 0.

run home.

will get you home after you have all your kerbals back in the CM and dumped the Ascent Module.

KOS files will be uploaded soon.

Edited December 24, 2013 by John FX

[John FX]

KOS files are now included...

[diomedea]

@ John FX: I believe you may be interested to know what the optimal ascent profile for Kerpollo 7 could be.

This was obtained through a numerical optimization tool ('Komputron' by Elington), and here are the KHDL vessel definition, flight profile obtained and a screencapture to show it on that tool. Used 22% of 3rd stage to a circular orbit @ 94.65 Km altitude, not too different from the performance on your opening post.

[John FX]

@ John FX: I believe you may be interested to know what the optimal ascent profile for Kerpollo 7 could be.

This was obtained through a numerical optimization tool ('Komputron' by Elington), and here are the KHDL vessel definition, flight profile obtained and a screencapture to show it on that tool. Used 22% of 3rd stage to a circular orbit @ 94.65 Km altitude, not too different from the performance on your opening post.

As it happens I am quite interested. So you loaded the craft file and it calculated the optimal ascent angles and so forth?

I shall have to investigate further.

Currently the KOS program is using about 10% of the third stage to get to 80km. (KOS has allowed a little tightening of the margins)

[diomedea]

Yes, that's more or less it.

The tool reads a craft in its definition language (KHDL), to this moment no automatic converter from a craft .file; however that's not too difficult to write even for a large and complex vessel as Kerpollo7 is. You may specify how much fuel to keep "in reserve", for the remainder of the mission, and the tool will automatically find the best angles and thrust to apply during the whole ascent, so to obtain the highest performance.

In some comparative tests I did, this tool could get higher than the ascent module in MechJeb, for the same vessel and fuel used.

This could be overkill in most cases, but sometimes a tiny difference in performance is all in making success or failure in space missions. As I reckon you're replicating Apollo Lunar missions, and those in reality were performed with very strict margins. Therefore believe even a slight increase in performance may be of importance here.

[John FX]

Well currently there is about 100Dv extra which could be removed easily in stage 3 (which, if removed, would create spare Dv in stages 2 then 1) and there is a fair amount spare in the descent stage if you have the right orbit although probably the right amount as Apollo 11 had 25 seconds of hover time spare when they landed and it seems like a similar amount. I know if you have a Pe over about 10km you don`t have enough fuel to land though...

The ascent stage has just about enough fuel to rendezvous with the Command module which has about the right amount of fuel also.

I have concerns though that I have made the craft too tight on the fuel for human players who might not have ultra skillz because lately I have just been flying it with KOS and refining it for that.

This is the core of the launch program.

set turnend to 65000.

set turnstart to 8000.

set turnstartangle to 65.

lock alty to (altitude-turnstart).

LOCK turnProfile to (turnstartangle-((alty/(turnend-turnstart))*turnstartangle)).

lock steering to heading (turnprofile,90).

I may try something new and see if I get more fuel left at the end. I`ll have a play with that program.

[John FX]

Ok so I have looked at the program and it suggests not a totally vertical ascent from the pad but one leaning more toward 89-85 degrees so I have started the gravity tun at about 100m and 89 degrees and by 6000m I am trying to be at 85 degrees. After that the flight profile is the same and I am ending up with more fuel as a result. So much so that the craft ended up out of the atmosphere during stage 2 (with still a decent orbital velocity) and the program thought it should execute a break and stage 2 staged too early. I`m launching with a fixed launch program again now.

More investigation is needed I think.

[John FX]

After further investigation, that trajectory was too steep and no benefit was found overall. I have done some fine tweaking to the flight profile after seeing the data (very useful) and I am happier with it now.

The launch program is now more robust as are some of the other programs as a result of this. I may do some node periapsis checking after the Mun burn node is generated to adjust the periapsis to be closer to the desired value. Currently it hits a periapsis between 20-50km and after the burn this can be between 5-20km. I`d like to make this be a node periapsis of 20km and an actual periapsis of 15km.

Now Sky has unblocked Imgur I can update the images on the first post. The new gallery is up and expect more images soon...

Checklist for attention.

Better Lander Legs.

Better Saturn V Outline (focus on stage 3/lander)

Make descent/Landing script for lander.

I`ve decided to have major versions which will have a main post title change and also prototypes which will include new features/scripts as they are developed.

I`ll post the new zip here soon but not this year

[John FX]

I was just looking at the Apollo Wiki at the Saturn V Instrument Unit, basically the KOS part. There was one on the first stage, another on the second stage and a third for the Lunar insertion stage.

The thing that struck me though was the actual checking and so forth that the real program did is *very* similar to the actual checking and so forth that my KerPollo program does. Stage1 is mostly controlled by timing triggers and an altitude check for pitchover (although this was simply a timed event for Apollo) The centre engine is cutoff and staging happens due to a fuel check on the two first stages exactly like Kerpollo and the program trusts stage 2 to get the craft to an Apoapsis above atmospheric height with minimal position checking (only a check for negative vertical motion) and then uses stage 3 for orbital insertion under finer control. Like Apollo the program then spends a couple of orbits finalising position in readiness for munar insertion. Like Apollo it decides when to burn mostly using positioning relative to Mun and knowing that the burn required is 872.55m/s After burning for Mun there is about 15 units of fuel left. the user then gets control, as with Apollo, to dock the CM with the lander. The program then separates the lander from stage 3 and moves the remnants of stage 3 away from the lander and CM. When I put a KOS unit in each stage I will program the stage 3 unit to perform a burn using the last 15 units of fuel to crash into Mun as Apollo did from 13 onward.

Kerpollo really does fly like the real thing.

I have also decided to mix and match my Apollo missions. KerPollo will have all the Ullage engines like Apollo 11 but a rover like Apollo 15 and it will have deployable experiments like Apollo 17. It also has science like KSP 0.23 hehe.

I will post an updated version here in the thread some time this week it will be Kerpollo 8P (Prototype). It uses a lot of tech from Kerpollo 7 but with some subtle staging differences, slightly improved scripts, and some tweaked parts...

I`ll run a full mission testing all the programs before I do though (launch, orbit, munar burn, CM->lander, munar capture and orbit adjustment, kerbin burn, and land)

[John FX]

Well for the nearly 8000 people who read but don`t post (and the few who do post TYVM)

Some new features for KerPollo 8P (prototype) stage 3 ullage motors for the second burn. Launchpad fuel to enable engine start at 6.4 seconds before liftoff with a gradually increasing throttle. A refined docking sequence for docking the CM to the lander. Numerous tweaks to the orbital maneuver program (read bug mitigation)

I`ve decided not to improve the actual route to Mun. Apollo took a couple of orbits to figure out where it was and exactly when to burn and so KerPollo will do the same. I just watched the Orbital Sciences Cygnus spacecraft launch which will resupply the ISS and even that with modern tech/software will take a couple of orbits to refine its orbit and rendezvous with the ISS.

I decided this looked cool (and low on parts) so I recreated it for KerPollo 8p (too many parts in the Apollo tower) The gallery is actually slightly incorrect for KerPollo 7, it`s under constant improvement and refinement so contents may not match the illustration etc.

If at any point anyone has suggestions for future features please let me know. One thing I am considering is a more realistic rover that folds into a slice of cake shape using Infernal Robotics. It may create room for better A.L.S.E.P.

Any views on that?

EDIT : I have improved the escape tower and brought it closer in line with the real one which had a solid rocket designed to push and tilt the escaping pod a little to the side so the main rocket would not hit it. It gives over 300m lateral movement with enough height that the chutes have enough time to open if the system is activated on the launchpad. I thought this would be the worst case scenario with all that fuel about so you would want to get at least 300m away. Either keep the tower on or stage until it drops.

Edited January 9, 2014 by John FX

[John FX]

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Here are some Telemachus graphs of the launch of KerPollo 8p. This should be useful to anyone wishing to fly the craft by hand.

As you can see, they are very similar to the actual launch profile. The margins are very very tight, a human pilot would have to gain fuel by limiting speed to terminal velocity to allow a margin for error simply to have enough fuel to get to Mun. After the Munar Insertion burn there is about 6.5 liquid fuel left in stage 3...

The second g-force image shows the graph with a throttle back for terminal velocity. I have decided against this now as this is not the way Apollo rolls but it is interesting to see the `cut out` part of the g-force that saves fuel. As someone has in their Sig on the forum, `Apollo tries to punch the sky and kill it` so no throttle back.

I have to travel today but expect a post of the latest build and software tomorrow.

[Rune]

Wow, you keep on putting more work on this... delightfully geeky to read about!

Rune. I'm much more dispersed.