do you take extra fuel with you?

[lammatt]

i mean... extra = excessively excessive.

i know i do if the weight is manageable, which usually is for the return capsule... (a 180unit LFO tank with a 909 yields around 2km/s of dV, why not)

i do this because it's more than often i forget to put a parachute on the capsule after it's launched into the skies.

and this extra fuel saved my kerbalnauts hundreds of times because it allows a powered landing.

how about you?

[problemecium]

Nope.

In fact as I get better at the game I've started bringing less fuel than I used to, even less than I once thought was the minimum necessary. This has especially been the case with Monopropellant - turns out for a small lander, the 15 units that come in the lander-can are enough to dock a few times so I needn't add weight with RCS balls.

[KerikBalm]

sussually take a couple hundred m/s extra, I try not to do more - well, for return trips and landers, I'm in the habit of setting up fuel depots and always use orbital rendevous.

[Idrryl]

I always estimate how much I need then make a vehicle with that dV (+/-300m/s). Bringing more fuel means more mass, more mass means bigger rocket, bigger rocket means more boosters, more boosters means more likely to crash

[Godot]

Well, for missions with return (including Mun / Minmus) I calculate so that I have an excess of 1000 - 1500 m/s dV upon return to Kerbin.

Reason is, that I play with Deadly reentry and thos 1000-1500 m/s come in handy to slow me down enough during reentry, that reentry heat doesn´t affect my spaceship (enabling me usually to recover the whole landing module (which has parachutes for this case) instead of just the heat shielded command module.

For other missions (like robotic missions) I calculate between 10-25% more than needed

[CalculusWarrior]

I vary between two extremes for my missions. Either I pack way more than enough fuel (so I'm ditching stages while they're still half-full, etc.), or I run out of fuel leaving LKO. There is no middle ground.

[Frank_G]

As much as needed, as less as possible, when a specific task is planned.

When doing large scale missions like the Jool Grand Tour i pack some reserves for sure, as you never know...

In general i like to achieve my goals with as much optimization as possible. Especially since i started first contract career mode.

[Wanderfound]

With rockets, I aim to have exactly enough fuel. I hate discarding a stage with unburnt fuel in it.

With spaceplanes: as much fuel as I can lift. Ain't no point in getting to orbit if you've got no fuel left to do anything with.

A properly designed spaceplane should be able to hit a 70km circular orbit with its tanks still half-full.

[Fendleton]

For contract work, I have a pair of small spacecraft. One is for rescuing kerbals, the other is for landing on Minmus or the Mun. Both of these are optimised and have only a little more than what is absolutely needed. The lander does a powered landing on kerbin with 5-10 units of fuel left.

Everything else I build has a safety margin.

[TimePeriod]

In general I take an extra 15-30% more fuel then needed.

[montyben101]

Not really, i only take whats necessary, though i hardy ever venture out of the kerbin system and mainly stick to LKO with stations and shuttles

[Ruthgar]

It depends on what I'm doing, in what game mode, and where I'm going. If I'm staying inside Kerbin SOI, I've got a lander setup that can get me to minimus with a transport section that usually has 20-30% fuel/oxidizer that I then dock with a station I have there in min orbit where I move all the extra transport fuel to except for what's needed for the deorbit burn (provided the tanks on the transport ship I have docked to the station aren't full, then the transport section I brought gets docked to the transport ship as an addittional engine/tank) then I proceed to land on Minimus ditching the transport tank after the deorbit burn (if I still have it), land there and do whatever I went there to do. I then launch from Minimus do a low power burn to return to Kerbin via a mun capture transfer, and while I'm there, land on the mun. I then take off go to kerbin orbit, rescue the lost kerbinaut, then do a minor deorbit burn to start aerobraking, and usually have 20-100 M/S of delta/v left for a final braking burn in the last half second to second. So yeah, inside of Kerbin SOI, my lander usually gets back into atmosphere with 1-5% of the total delta/v it had, but have had a few missions where my final deorbit burn after rescuing the lost kerbin has been done using the RCS props.

As far as my interplanetary transports go, I typically try to leave kerbin SOI with 50% or more of the delta/v needed for the round trip and at least one lander full refuel (monop, fuel, and oxidizer) as I've lost count of the number of times I've miscalculated the hoffman transfer burn badly and have needed a 300-500 M/S correction burn (my normal interplanetary hoffman transfers do normally need a plane change & correction burn, but it's usually just in the 10-50 M/S range). I'm really glad I do this even if it takes the extra time to build/fuel the interplanetary transport as on my latest trip to duna and after landing on Duna, I had my 'Apollo 13' incident. I went ahead and did my orbital docking after the lander ascended from Duna in the darkside of Duna. In doing so I had forgotten to take into account the orientation of the transport and wound up crashing the lander at 10-20 M/S as I was doing my rendevous speed kill burn into the rear end of the transport. The resulting explosion completely crippled the transport rendering it incapable of managing a stable straight burn even at just 1% thrust, however, enough tanks did survive so that the lander was able to dock up, detach the ones that would unbalance the thrust of the lander even more (damage to the lander rendered it offbalance, and even with ballasting the contents of the fuel tanks the lander could only maintain 40% thrust while towing the remaining tanks without spinning, it could manage 60% without the tanks sustained, and brief bursts of 100% provided the rcs was on) So I then proceeded to limp my way back to kerbin ditching tanks as they emptied (love love love having built a modular transport ship, next time I need to remember to build more then one of the primary engine stages that has a forward facing docking port) In this case, having way more fuel than I needed made sure I did not need a rescue ship.

[Rus-Evo]

Its too hard to get transfers correct when you are basically eyeballing the angles and comparing to the diagram for the burn, so yeah MOAR fuel to get you through.

[Landge]

I send fuel out ahead of any kerbal crewed missions that are beyond Kerbin's SOI. Just incase I want to make multiple landings on another planet or moon(s). Once more biomes are added to the rest of the game you'll be glad you have that extra fuel waiting in orbit.

Edited July 27, 2014 by Landge

[Madrias]

I'd rather have 6 tons too much than 6 units too few. Sure, I spend more getting it up there, but at the end of the day, what matters is that things got where they needed to go, and I had plenty of spare fuel for doing stupid stuff like not using perfect efficiency. After all, I suck with rockets, but until I get spaceplanes, I have to do things this way. Once I've got planes, all those extra fuel cans end up being dumped on stations with docking ports attached, so after I have docking ports and spaceplanes, I never worry about that 'half empty fuel can' left 'floating in orbit' because I'll just pick it up, give it a shove, dock it with the station, and once it's empty, hook it to the belly-port and carry it down for a nice, safe landing.

[magnemoe]

It depend a lot of the mission, milk runs like returning to Minmus with a kethane miner has tend to run with low margins, more so if I have the fallback to dock with station if I'm to low to land.

Going to Moho and 1 km/s spare is far below the safety margin, that is an mission who return should have 10 km/s and additional safety features like dumping stuff

Jool is 2 Km/s, however 2.5 is a minimum and that is Laythe orbit after direct aerobrake.

Now LKO is 4.5 km/s however in 0.24 I use a lot of SRB and they are less effective than shown in mechjeb dV view

[Moar Boosters]

Generally yes. Any excuse to build my rockets bigger.

[cantab]

For me it varies. "Custom" ships tend to run pretty slim margins, but often I using modular ships with standard transfer stages so there's loads of excess dV. Of course for an interplanetary trip I have the option of using that to force an "express" transfer, for example I'm planning on making Kerbin-Jool in 140 (Earth) days.

[SciMan]

Depends on what you mean by "extra" fuel, but I generally do take more fuel than strictly needed.

Any landers must be able to make orbit after landing, and then re-dock with the transfer stage if its an interplanetary mission.

The transfer stage + lander is not required to be able to get back to Kerbin on internal fuel supplies alone.

That's what the fuel tankers I always send with my interplanetary missions are for. While I planned on using that fuel to begin with, it is technically extra in that it's not part of the main mission spacecraft.

Even if the tankers don't count as extra, I usually end up with plenty of left-over fuel.

That's probably because I design my ships to be capable of doing the mission without any aerobraking and still having at least 1 km/s delta-v left over. When piloting them, I use aerobraking and aerocapture as much as possible.

Nothing says "Plan B" like having 2 or 3 km/s delta-v worth of fudge factor. That's useful because I never plan out what inclination I'll end up in. I adjust that once I get to the target.

Edited July 27, 2014 by SciMan

[Alshain]

When designing electronic circuit boards, the general rule of thumb is to add 20% storage (memory, flash, etc) than what you need. I use the same rule of thumb for upper stages, stages getting to Kerbin orbit I do not.

[Mister Kerman]

This one is tough for me. I have to play it by feel since I just play stock KSP. I always go with "more is better" approach over the "skin of my ass" method. I'm just more comfortable with muscling through space with plenty of gas... If space ships were cars I guess I drive a Hummer.

Edited July 27, 2014 by Mister Kerman

[plaiddragon]

My rockets launch stages often can get into interstellar space I bring WAY too much fuel XD

[KerbMav]

Using KER and trying to bring just enough with a buffer - launch stages usually are not empty when they get dropped back to Kerbin though, my ascent profile seems to be quite inconsistant from launch to launch.

[rdfox]

When I design my ships, I tend to plan for about 110% of the delta-V required for the actual mission profile. I then get as close as I can to that number (without going below 110%) using the standard parts; this usually has me in the range of 115%, though on some of my high-Isp, low-thrust transfer stages, I've had it be a case of, "well, I can either have 90% of the required delta-V, or 200% of it, and NOTHING in-between... guess I'll go 200%."