refuel missions are hard

[Perotis]

I cant believe how difficult is is to get a full orange tank to a place like the mun (orbit)

[Guest]

Three Mammoths (2+1 onioned) and a Rhino second stage will get some 190 tons to LKO.  That's plenty for an orange tank and a transfer stage to Mun.  Hell, you could probably do the whole thing with a single Mammoth and some boosters with a Poodle upper.  You only need like, what, 1100m/s to get into orbit around the Mun?  Add another 200~300m/s for safety and rendezvous and call it good.

Edited February 8, 2016 by regex

[Tantalus]

1 hour ago, Perotis said:

I cant believe how difficult is is to get a full orange tank to a place like the mun (orbit)

Why don't you produce your fuel at mun and just carry it up into orbit? I'm even refuelling my LKO station from the mun.

Regards

Tantalus

[Corw]

2 hours ago, Tantalus said:

Why don't you produce your fuel at mun and just carry it up into orbit? I'm even refuelling my LKO station from the mun.

Regards

Tantalus

He may not be in that far into tech tree?

Would be better if you could add more details which part of the mission is hard?

[Tantalus]

46 minutes ago, Corw said:

He may not be in that far into tech tree?

Maybe.

@Perotis if you have trouble to get your payload into LKO at all, you might try to drain a bit of fuel from your payload-tank. About 20% of an orange makes a huge difference at launch. Sure it may require an additional flight, but may reduce frustration. Or you take a look at kerbalx to pick up some inspiration.

Regards

Tantalus

[RizzoTheRat]

How much fuel do you need at the Mun?  This doesn't help if the aim to have a full orange tank there, but I just send extra fuel up with any mission that's going there rather than sending specific fuel missions, so any crewed ship going to the Mun station tends to be packing twice the dV it needs, and any excess fuel is drained off leaving them with the 300 or so it needs to get back home

[Reactordrone]

After noticing that the mainsail had very similar stats to the Proton's first stage engines I made a proton replica yesterday that can easily get 60t into low Munar orbit.

[KerikBalm]

orange tank = 36 tons. I'll add another 4 tons for engines and guidance to get it there... call it 40 tons of payload/dry mass (excluding tanks which I'll factor in later)

We'll be generous and calculate for 1200 m/s from LKO (to not just intercept, but insert into low orbit)

No nukes, just a poodle: 350 Isp

1200= 9.81*350* ln (X/40)

ln (x/40) = 0.35

X/40 = 1.42

X= 56.7

56.7-40 = 16.7 tons of fuel needed to send 40 tons to Low Mun Orbit from LKO... but we're ignoring the tank mass needed to store those 16.7 tons.

That comes out to 1/8th the fuel mass, or another 2.09 tons. Rather than doing more complex math, I'll do 1 more iteration for an approximation...

X/42.1 = 1.42

X= 59.8         59.8-42.1 = 17.7... 1.0 tons more fuel needed.. and the dry mass to add on another 1.1 tons is 0.125 tons more dry mass... I'll stop here.

1x Roxomax x200-32 and 1x rockomax 200-8 with a poodle attached, and another 2 tons for guidance, docking ports, power generation, etc, gets an orange tank to low munar orbit from LKO.

22.5 tons+ 40 tons.... all you need to do is have a launcher that can lift 63 tons to orbit... which is not too hard

[Wonky kergineer]

I'm lacking all of the +500 science upgrades and i find it definitely hard to refuel my Mun OS. What i do is i have a launcher which allows me to achieve LKO with an orange tank plus two X200-32 fuel tanks keeping about 1/3 of it's fuel, and then i launch two more without the x200-32's, then refuel the first one with the other 2, then reach for the Mun. Yeah, it's slow, and yeah, i'm probably wasting a lot of resources, but at the moment that's the best solution i could come up with.

[Tfin]

Yeah... I've currently got a contract to build a station for 5 that has 2000 units of LF aboard. I see no reason to send up liquid fuel without oxidizer, so at 45/55, that's... a lot of fuel. I've only unlocked the smallest docking port, and didn't even have 2.5m engines when I got the contract.

I guess doing it will trigger more fuel-shipping contracts.

[Rarity]

I'm terrible at refueling missions.  My Kerbals pray that their gas light never comes on, lest they have to get out and push.

[Wonky kergineer]

My previous post is no longer valid; Now i can put the orange in orbit with 100% fuel, since i've upgraded my launching pad and have no weight limits.
My launcher is now the orange with a mainsail surrounded by six X200-32 packing skippers, asparagus staged. I'm pretty confident i can now redesign this launcher to take the full orange in Mun orbit, but it will be, as always, trial and error for me.

[Perotis]

I guess I didn't explain my situation.  I'm in career mode and still haven't unlocked all the sciences.  My current mission is trying to rescue a stranded (no fuel and tipped over) mission on the Mun with a couple hundred science on board.  I'm planning on getting the nuclear engines next.  I didn't think this science recovery mission was going to take so many attempts.

 

[Nich]

I forgot what the limit is on a level 2 launch pad but I think its 142 tons. If that's the case I don't think it is possible to get an orange tank into orbit much less to the moon. If I remember correctly 26% payload fraction is really good for a rocket but requires the top tier engines. That would be 36 tons or less is about all you can put on orbit.

I'm with the other guys whenever I send a crew rotation I send the biggest crew rotation vehicle possible with way too much fuel to refuel of the station

Edited February 8, 2016 by Nich

[Chakat Firepaw]

1 hour ago, Perotis said:

I guess I didn't explain my situation.  I'm in career mode and still haven't unlocked all the sciences.  My current mission is trying to rescue a stranded (no fuel and tipped over) mission on the Mun with a couple hundred science on board.  I'm planning on getting the nuclear engines next.  I didn't think this science recovery mission was going to take so many attempts.

Are you trying to do something silly like recover the entire ship?

Just send a small lander with a probe core and an empty crew cabin.  Have your stranded Kerbals carry the science over to the rescue ship when they EVA and abandon the wreck.

[Fearless Son]

1 hour ago, Chakat Firepaw said:

Are you trying to do something silly like recover the entire ship?

Just send a small lander with a probe core and an empty crew cabin.  Have your stranded Kerbals carry the science over to the rescue ship when they EVA and abandon the wreck.

That is what I would do, unless the contract was something like "Recover [Name] Kerman and his/her vessel", which can come up.  But I figured you would need a pretty high reputation and certain necessary technologies for that.  

[Perotis]

3 hours ago, Chakat Firepaw said:

Are you trying to do something silly like recover the entire ship?

Just send a small lander with a probe core and an empty crew cabin.  Have your stranded Kerbals carry the science over to the rescue ship when they EVA and abandon the wreck.

Yea. That's was my next idea.  

[Chakat Firepaw]

On 08/02/2016 at 1:41 PM, Fearless Son said:

That is what I would do, unless the contract was something like "Recover [Name] Kerman and his/her vessel", which can come up.  But I figured you would need a pretty high reputation and certain necessary technologies for that.  

The bit about having to recover the science implies that this is one of his missions that went bad rather than one generated by the contract system.