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[It's finally here!] Apollo Replica "MUNBUG XII" Saturn V, CSM, Lander, Buggy

Mulbin
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Mulbin

Mulbin

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Doesn't the ascent stage have its own fuel supply? That's what it looks like to me.

It had plenty of fuel to get to orbit.

Thinking about it more, you probably have fuel lines connected between the ascent stage and descent stage. I will brb and tell you how much fuel remained in the descent stage.

I don't have a number for you, but I estimate there was maybe 380 units of liquid fuel left after landing. I will have to do another landing and check values again.

Wow... lol I need to rethink my landing technique ;) Yes the fuel lines cross between the modules so once the descent stage runs out it starts taking it from the upper stage. I usually use about 100 of the upper stage fuel too! Will experiment with your landing technique (which is actually much more like Apollo) and see what weight I can cut out (and replace with more MMSEP payloads!!)

Damn... I thought I was done... looks like there will be a Munbug IX after all!

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AncientAstronaut

AncientAstronaut

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Wow... lol I need to rethink my landing technique ;) Yes the fuel lines cross between the modules so once the descent stage runs out it starts taking it from the upper stage. I usually use about 100 of the upper stage fuel too! Will experiment with your landing technique (which is actually much more like Apollo) and see what weight I can cut out (and replace with more MMSEP payloads!!)

Damn... I thought I was done... looks like there will be a Munbug IX after all!

Landing from 2.5 --> 3km is MUCH more realistic to an actual Apollo descent profile. It's also the best way to land. Start from a low periapsis of 3km and just practice killing your vertical speed enough to make sure you don't hit the ground before you kill horizontal velocity. Even MechJeb cannot do this because it's simply the best way to do it if you can pilot.

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wilywampa

wilywampa

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How much ÃŽâ€V are people having left in the third stage after circularizing Kerbin orbit? The best I've been able to do is 854 m/s using MechJeb, which is just a few m/s short of what's needed for TMI. I used 71 km orbit altitude, 8 km turn start altitude, 65 km turn end altitude, and 40% turn shape to get 854 m/s.

Also, I just today realized that Mun is only 12,000 km from Kerbin compared to 384,400 km on average from Earth to Earth's moon. Why such a huge difference?

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Kosmo-not

Kosmo-not

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Wow... lol I need to rethink my landing technique ;) Yes the fuel lines cross between the modules so once the descent stage runs out it starts taking it from the upper stage. I usually use about 100 of the upper stage fuel too! Will experiment with your landing technique (which is actually much more like Apollo) and see what weight I can cut out (and replace with more MMSEP payloads!!)

Damn... I thought I was done... looks like there will be a Munbug IX after all!

You got to my post before I realized I could get the numbers from the descent stage. My old post is updated. It had about a minute of fuel left.

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Bigred2989

Bigred2989

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How much ÃŽâ€V are people having left in the third stage after circularizing Kerbin orbit? The best I've been able to do is 854 m/s using MechJeb, which is just a few m/s short of what's needed for TMI. I used 71 km orbit altitude, 8 km turn start altitude, 65 km turn end altitude, and 40% turn shape to get 854 m/s.

Also, I just today realized that Mun is only 12,000 km from Kerbin compared to 384,400 km on average from Earth to Earth's moon. Why such a huge difference?

Because everything in KSP is only a fraction to scale with real life. Kerbin is a lot smaller than Earth IIRC.

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Mulbin

Mulbin

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How much ÃŽâ€V are people having left in the third stage after circularizing Kerbin orbit? The best I've been able to do is 854 m/s using MechJeb, which is just a few m/s short of what's needed for TMI. I used 71 km orbit altitude, 8 km turn start altitude, 65 km turn end altitude, and 40% turn shape to get 854 m/s.

If you come up a little short on your transfer burn you can afford to transfer a little fuel from the CSM, also the third stage has plenty or RCS you can use to assist. Fuel is very, very tight on the third stage, I generally find I can squeeze just enough out as long as my orbit is dead on 90 degrees... If I have to adjust my normal +/- during transfer it may not make it. Now I have learnt about Kosmo-not's more efficient landing profile I will be shifting fuel from the lander to the third stage on Munbug IX

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Mulbin

Mulbin

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Here is new video of landing the lander on the Mun. I just love the look and feel of it. Landed with 7.37% fuel left in the descent stage.

http://youtu.be/MsES1HxnhLc

Hope you don't mind but I've pinned your video to the main post to help others master the landing.

I just completed a landing with your profile myself... it certainly saves fuel! I have 140 more fuel left than usual! I will likely remove 90-120 and add it to the third stage to make Free return a bit easier.

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Mulbin

Mulbin

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This rocket is amazing, thanks for making this rocket. I really want to try it, and I will soon hopefully.

As long as people want them, i'll make them! Hope your first mission goes well!

What is this engine at the CSM?

It's a skipper. It is attached to struts to push it onto the CSM body.

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Gojira

Gojira

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Okay I'm sorry but you NEED a simplified Soviet flag. It simply doesn't work otherwise.

Also, so now I'm in a 70km orbit, do I need to either a) calculate partial dV of a stage or B) transfer fuel from the CSM to the J4-b (and how much should I transfer? I still have 49.64 LF in the radial tanks in the J-IVb).

Edited by Gojira
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Mulbin

Mulbin

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Okay I'm sorry but you NEED a simplified Soviet flag. It simply doesn't work otherwise.

I've already made a soviet flag...

screenshot18_zps277306c2.jpg

You can download it here

http://www./view/zd4i9suxx98p4fj/KSSR.png

Also, so now I'm in a 70km orbit, do I need to either a) calculate partial dV of a stage or B) transfer fuel from the CSM to the J4-b (and how much should I transfer? I still have 49.64 LF in the radial tanks in the J-IVb).

You've ended with quite low fuel.. I usually have 90 - 95 LF in each radial tank after orbit insertion. So you are between 320 and 360 fuel short... you will need to transfer half of your CSM fuel to make the transfer to the Mun. Which may mean you won't make it home! Of course if you use the new landing profile then you will have a little left in the lander ascent stage to transfer back across. Or you could abandon hope of FRT and just go for a standard Mun intercept (which takes less fuel)... or complete the FRT with the CSM/LEM after ditching the third stage.

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Gojira

Gojira

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I've already made a soviet flag...

[iG]http://i1024.photobucket.com/albums/y302/bloobot/screenshot18_zps277306c2.jpg

You can download it here

http://www./view/zd4i9suxx98p4fj/KSSR.png

You've ended with quite low fuel.. I usually have 90 - 95 LF in each radial tank after orbit insertion. So you are between 320 and 360 fuel short... you will need to transfer half of your CSM fuel to make the transfer to the Mun. Which may mean you won't make it home! Of course if you use the new landing profile then you will have a little left in the lander ascent stage to transfer back across. Or you could abandon hope of FRT and just go for a standard Mun intercept (which takes less fuel)... or complete the FRT with the CSM/LEM after ditching the third stage.

I screwed up bad with orbital insertion. With the two gimbals off on the first stage it likes rolling as well as going to the 90 degree heading... So is there a more efficient ascent profile? Because the one you provide isn't working for me.

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Gojira

Gojira

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I've already made a soviet flag...

screenshot18_zps277306c2.jpg

You can download it here

http://www./view/zd4i9suxx98p4fj/KSSR.png

You've ended with quite low fuel.. I usually have 90 - 95 LF in each radial tank after orbit insertion. So you are between 320 and 360 fuel short... you will need to transfer half of your CSM fuel to make the transfer to the Mun. Which may mean you won't make it home! Of course if you use the new landing profile then you will have a little left in the lander ascent stage to transfer back across. Or you could abandon hope of FRT and just go for a standard Mun intercept (which takes less fuel)... or complete the FRT with the CSM/LEM after ditching the third stage.

I screwed up bad with orbital insertion. With the two gimbals off it likes rolling as well as going to the 90 degree heading... So is there a more efficient ascent profile? Or could you do the minor update to Munbug IX (if it's minor, of course)?

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Mulbin

Mulbin

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I screwed up bad with orbital insertion. With the two gimbals off it likes rolling as well as going to the 90 degree heading... So is there a more efficient ascent profile? Or could you do the minor update to Munbug IX (if it's minor, of course)?

I generally start my turn at 8km, pitching over to 15-20 degrees from vertical and follow the prograde marker roughly down to 45 degrees... After your AP hits 35km you can start to drop below 45 degrees. I usually turn to zero degrees (horizon) when my AP hits about 55km and is about 1 - 1 1/2 minutes away. I usually have an AP of about 65km when I hit the third stage.

When I get round to updating Munbug I won't be adding any extra fuel, just moving a little from the lander to the third stage.

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Mulbin

Mulbin

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Well. . . what else can I say. . . if it's by Mulbin. . . you know it's gonna be both eye-candy AND a pleasure to fly. :)

thanks... glad you are enjoying it! Already got a change list building up for Munbug IX

In other news - The Munbug Series craft have just hit 5000 downloads!

Edited by Mulbin
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Mulbin

Mulbin

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Mulbin my Hero one question: do you have any advice for archiving a free return trajectory? i have difficultys to do so ... any help would be awesoe :)

I usually set it up on a maneuver node - Assuming you are orbiting Kerbin at aprox 71km, It should take no more than 878m/s DV

Adjust it by setting the node up to give predicted burn of 878m/s, prograde... then move the position of the entire node (i.e. altering the time of ignition) until the flight path is the right shape. You may also need to add a little Normal +/- to correct the attitude.

If you have achieved Kerbin Orbit efficiently you should have between 90-100 liquid fuel in each of the third stage radial tanks which is just enough... if you are short then take a little from the CSM. Munbug IX will have a bit more fuel in the third stage... just tested it and achieved FRT with fuel to spare.

Edited by Mulbin
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