Help with upgrade station contract

[Neil Kermstrong]

I got a contract where I need to upgrade my mun space station, and for it I need for it to support 13 kerbals and 4000 total fuel.

The crew capacity is fine, but I have no idea on how to complete the fuel one. 

A fuel tank with almost 3k liquid fuel and 3500 oxidizer has a mass of 36t, I don't have how to launch this thing, its too heavy, and I don't want to launch like 3 or 4 rockets costing >100k each to complete a contract that gives only 288k

[DerekL1963]

1 hour ago, Neil Kermstrong said:

A fuel tank with almost 3k liquid fuel and 3500 oxidizer has a mass of 36t

That's an orange tank, it takes some practice to build a bird that large but it's pretty much straightforward.  The Sandbox is useful for such experiments.

[StrandedonEarth]

18 minutes ago, DerekL1963 said:

That's an orange tank, it takes some practice to build a bird that large but it's pretty much straightforward.  The Sandbox is useful for such experiments.

Yes, what he said, and bear in mind that it only says fuel, so if you launch the orange tank you can empty the oxidizer first. Or use one or more of the LF only (spaceplane) tanks. Eight MK1 LF tanks at 400 each would do, clustered together.

[DerekL1963]

3 minutes ago, StrandedonEarth said:

Yes, what he said, and bear in mind that it only says fuel, so if you launch the orange tank you can empty the oxidizer first.

If it only says fuel...  "Total fuel" might mean something different.

[StrandedonEarth]

43 minutes ago, DerekL1963 said:

If it only says fuel...  "Total fuel" might mean something different.

Can always put 4k of only fuel on the pad and see if it ticks that contract parameter

Edited August 24, 2020 by StrandedonEarth

[Spricigo]

3 hours ago, Neil Kermstrong said:

I don't want to launch like 3 or 4 rockets costing >100k each

You need to cut a lot of dead weight  if they are costing that much.

 

 

[swjr-swis]

6 hours ago, Neil Kermstrong said:

A fuel tank with almost 3k liquid fuel and 3500 oxidizer has a mass of 36t, I don't have how to launch this thing, its too heavy, and I don't want to launch like 3 or 4 rockets costing >100k each to complete a contract that gives only 288k

If you have the tech, use a spaceplane that can return again to get most of the craft cost refunded. It also makes it easier to send up more than one tank if needed.

[s_gamer101]

4 hours ago, swjr-swis said:

It also makes it easier to send up more than one tank if needed.

If you are talking about an SSTO spaceplane, I don‘t think SSTO‘s make things easyer.

[swjr-swis]

1 minute ago, s_gamer101 said:

If you are talking about an SSTO spaceplane, I don‘t think SSTO‘s make things easyer.

Load to runway. Engage SAS, set it to Orbital mode, throttle to full, stage. Plane will take flight hands-free. At 500 m/s, switch to follow prograde. At 22km altitude, action group 1 to switch to closed cycle. Cut throttle when Ap is 72km. Set up the maneuver node and circularize.

For the return, just fire retrograde at the right time (crater rim), point radial out until plane starts wanting to nose down, glide her over the mountains and onto the runway, at a stall speed of 25-30 m/s.

Recover, load with a new payload, rinse and repeat.

Short of letting a mod like MechJeb or kOS handle it, it hardly could be any easier.

[s_gamer101]

I don‘t talk about flying an SSTO, i talk about building one, but you’re right about flying an SSTO. An SSTO that can bring an orange tank to LKO isn‘t that hard to build either but don‘t forget that the station is in a Mun orbit. When you have to add nuclear engines for transfer to an SSTO, the design becomes a lot more complicated.

[Okhin]

You only need Liquid Fuel for those contracts. So don't bother with tanks with LF and Ox. The most efficient fuel tank is the Mk0, but you will need a lot of them clustered to get close to the 4000 LF needed, so I'll suggest the same than @StrandedonEarth, go for MK-1 Fuel tanks. They only have LF in them, so they're a bit smaller and lighter than their LF+Ox counterparts.

Cluster them together (engines plates do marvel for those if you have them, else just radial symmetry them around some parts, or another one of them. Should weight a lot less than a Radial orange tank.

If your space station is small, you can probably even do it in one launch, depending on your unlocked science.

[Neil Kermstrong]

Thank you everyone, I am trying too build a space shuttle to do this contract

[swjr-swis]

4 hours ago, s_gamer101 said:

but don‘t forget that the station is in a Mun orbit. When you have to add nuclear engines for transfer to an SSTO, the design becomes a lot more complicated.

Mun orbit was mentioned and I indeed overlooked that. Still, replace the single orange tank by a smaller set of LF tanks and a small orbital tug and I think it would still fit in the cargo bay... just one more launch, and then from LKO, have the tug do the Munar injection.

[Neil Kermstrong]

15 hours ago, StrandedonEarth said:

Yes, what he said, and bear in mind that it only says fuel, so if you launch the orange tank you can empty the oxidizer first. Or use one or more of the LF only (spaceplane) tanks. Eight MK1 LF tanks at 400 each would do, clustered together.

 

5 hours ago, Okhin said:

You only need Liquid Fuel for those contracts. So don't bother with tanks with LF and Ox. The most efficient fuel tank is the Mk0, but you will need a lot of them clustered to get close to the 4000 LF needed, so I'll suggest the same than @StrandedonEarth, go for MK-1 Fuel tanks. They only have LF in them, so they're a bit smaller and lighter than their LF+Ox counterparts.

Cluster them together (engines plates do marvel for those if you have them, else just radial symmetry them around some parts, or another one of them. Should weight a lot less than a Radial orange tank.

If your space station is small, you can probably even do it in one launch, depending on your unlocked science.

Well I know about that but if I only put LF it will have almost no use

[Superfluous J]

1 hour ago, Neil Kermstrong said:

Well I know about that but if I only put LF it will have almost no use

Well, it will complete the contract...

Frankly, I use the existence of fuel in a station or base contract as a red flag to avoid said contract like the plague.

[s_gamer101]

I‘ve never had trouble with such contracts. I once had a Mun station expansion contract like this too, and I sent a jumbo tank with a not even so big rocket. The transfer stage had a tank that was half as big as a jumbo tank and a skipper engine and I don‘t remember the other stages

[Neil Kermstrong]

22 minutes ago, s_gamer101 said:

I‘ve never had trouble with such contracts. I once had a Mun station expansion contract like this too, and I sent a jumbo tank with a not even so big rocket. The transfer stage had a tank that was half as big as a jumbo tank and a skipper engine and I don‘t remember the other stages

Well, the rocket I was using to expand my station was too big and I had some problems handling it (Even when the part I wanted to dock weighted like 12t) 

I don't even want to imagine how hard it would be to send an entire fuel tank, that weights 36t to the station.

However, I just rememberd i have almost 1k of fuel in my station (because of the fuel tanks I used to dock each part of it) so maybe if I managed to send the jumbo successfully, and docked with some fuel from the last stage it would complete the contract

 

Also, I have managed to build a shuttle but for some reason it can't go straight up, every time I launch it the shuttle just points to the ground moments after I launch

[Okhin]

2 hours ago, Neil Kermstrong said:

 

Well I know about that but if I only put LF it will have almost no use

Wrong. You can use it as a refuel point for LF only engines Ie: nukes)

[Neil Kermstrong]

4 minutes ago, Okhin said:

Wrong. You can use it as a refuel point for LF only engines Ie: nukes)

wait nuclear engines don't use oxidizer? 

[swjr-swis]

9 minutes ago, Neil Kermstrong said:

I have managed to build a shuttle but for some reason it can't go straight up, every time I launch it the shuttle just points to the ground moments after I launch

Well, shuttle-style vehicles are genuinely difficult to get right. Rockets and spaceplanes tend to be easy in comparison, because their thrust almost naturally aligns with the center of mass of the vehicle. With shuttles, you have to design it to specifically ensure the thrust aligns, and stays that way even while the fuel is being expended. If you're going into it eyes open good for you, but be aware that It's a very real challenge.

If you're set on a vertical launch and are not particularly attached to a shuttle, I'd suggest a more traditional rocket would be easier.

2 minutes ago, Neil Kermstrong said:

wait nuclear engines don't use oxidizer?

They used to when they were first instroduced, but they were changed to LF-only. Have been for a good while now.

[Okhin]

2 minutes ago, Neil Kermstrong said:

wait nuclear engines don't use oxidizer? 

Nope. They do not. That's what make them interesting (that and their good ISP)

[Neil Kermstrong]

2 minutes ago, Okhin said:

Nope. They do not. That's what make them interesting (that and their good ISP)

 

5 minutes ago, swjr-swis said:

Well, shuttle-style vehicles are genuinely difficult to get right. Rockets and spaceplanes tend to be easy in comparison, because their thrust almost naturally aligns with the center of mass of the vehicle. With shuttles, you have to design it to specifically ensure the thrust aligns, and stays that way even while the fuel is being expended. If you're going into it eyes open good for you, but be aware that It's a very real challenge.

If you're set on a vertical launch and are not particularly attached to a shuttle, I'd suggest a more traditional rocket would be easier.

They used to when they were first instroduced, but they were changed to LF-only. Have been for a good while now.

Oh well, guess I know what is my next tech-tree unlock then 

6 minutes ago, swjr-swis said:

Well, shuttle-style vehicles are genuinely difficult to get right. Rockets and spaceplanes tend to be easy in comparison, because their thrust almost naturally aligns with the center of mass of the vehicle. With shuttles, you have to design it to specifically ensure the thrust aligns, and stays that way even while the fuel is being expended. If you're going into it eyes open good for you, but be aware that It's a very real challenge.

I have only launched normal rockets since I started playing this game so now I want to try and build a functional shuttle, it's mainly because I love planes and rockets, but a space shuttle is literally what would come if a rocket and a plane had a baby

[swjr-swis]

12 minutes ago, Neil Kermstrong said:

I have only launched normal rockets since I started playing this game so now I want to try and build a functional shuttle, it's mainly because I love planes and rockets, but a space shuttle is literally what would come if a rocket and a plane had a baby

It's a nice challenge to tackle, very worth the effort. If you want to shop around for some design ideas and concepts, there's a long-running thread in the challenge forum specifically about shuttle missions.

[Neil Kermstrong]

3 minutes ago, swjr-swis said:

It's a nice challenge to tackle, very worth the effort. If you want to shop around for some design ideas and concepts, there's a long-running thread in the challenge forum specifically about shuttle missions.

I'll check it then. Thanks!

[DerekL1963]

2 hours ago, Neil Kermstrong said:

I don't even want to imagine how hard it would be to send an entire fuel tank, that weights 36t to the station.

It's no different than sending a 3.6t payload to the station...  You just need a bigger booster, transfer stage, etc...  Just takes practice and experience.