Part Recovery Rates

[Pecan]

This is my first go at a VTOL SSTO for an orange tube (plus ancillaries) - 40t payload. In this version the payload is carried low in the centre to keep the CoM down.

[occ]

So, I observed that landing near Kerbal Space Center nets me between 90%-98% of the cost of my vessel's parts back when recovering, so I decided to run some tests.

• I'm happy to report that you get 100% of your Funds back for parts that are on the Launchpad. This is nice for those time I just want to see how much the vessel weighs, or that my ladders are placed correctly. Great idea, Squad!
  
• Debris that land on the surface of Kerbin without a probe core or command pod [uPDATE: apparently DO return funds depending on distance to KSC as long as they land while in physics range (<2.5km) and don't auto-unload, and you go to the tracking station to recover them. You get no notification of the Funds returned, but your Funds counter will reflect the new amount.] <s>don't net ANY funds. 0%. This is sad considering you can recover science from them. Why not Funds?</s>
  
• Landing as far away as possible from KSC, i.e. the exact opposite side of the planet, nets you only 10% of your money back. Ouch!
  

We have established the percentage of funds recovered for at KSC, near KSC, and on the other side of the planet. But what is the actual rate of percentage loss as recovery sites occur farther and farther away from KSC? What if, for some reason, I recover craft/debris from 50km away? 100? 200? More to the point, are percentage losses plotted linearly, or on some kind of curve? If so, what kind?

- - - Updated - - -

I realize there might not be much data on this subject, but I would be interested in learning more.

[Dr-Drunk]

I wonder but haven't found out yet, do you pay less money if you start with empty tanks? Hmm, time for some experimentation.

Why? Because I usually disable the RCS fuel in the command pod, certainly on rockets that aren't even fitted with RCS ports, the extra weight does make a difference in some cases. (I'm a minimalist)

Yea the fuel cost is deducted if you empty the tanks. Fuel doesn't seem to cost all that much though. On my standerd lifter wich often has about half fuel left on re-entry the recovery comes down to about 400 funds wich for a 2.5m rocket capable of lifting tens of tons into orbit isn't a whole lot.

Pretty much 90% of your returns are on the actual tank itself, not the contents. Maybe someone should mod that to make the fuel cost more. I mean in real rockets it's mostly the cost of fuel that makes launches so expensive.

[merendel]

Pretty much 90% of your returns are on the actual tank itself, not the contents. Maybe someone should mod that to make the fuel cost more. I mean in real rockets it's mostly the cost of fuel that makes launches so expensive.

You have that backwards. fuel costs are very cheep compared to throwing away multi million dollar rocket engines every launch. If the fuel was the bulk of the cost in a space launch there would be little reason for SpaceX's push for reuseable rocket stages. They are hopeing to reduce the cost dramaticly if they can make a launch stage that is easy to recover and refurbish. You may be thinking the fuel cost is high due to how much more expensive shuttle launches were compaired to normal rockets but most of the shuttle expense was all the refurbishment it took after every flight to actualy reuse that deathtrap somewhat safely.

[StrandedonEarth]

in real rockets it's mostly the cost of fuel that makes launches so expensive.

Elon Musk has said that fuel is less than 1% of the cost of a launch. While I imagine LH2 costs more, it's still a minor cost. It's the engines that cost the most.

I have a 160ton-to-orbit lifter (aka Goliath) where the only disposable parts are 36 S1 srb's. The 14orange jumbos and 7 mainsails are recovered along with a metric crapton of 'chutes. It can loiter in orbit until I'm ready to land it.

[magico13]

We have established the percentage of funds recovered for at KSC, near KSC, and on the other side of the planet. But what is the actual rate of percentage loss as recovery sites occur farther and farther away from KSC? What if, for some reason, I recover craft/debris from 50km away? 100? 200? More to the point, are percentage losses plotted linearly, or on some kind of curve? If so, what kind?

- - - Updated - - -

I realize there might not be much data on this subject, but I would be interested in learning more.

It's linear. This is what KCT/StageRecovery use, and without going into too much detail this is also what KSP uses: Mathf.Lerp(0.98f, 0.1f, (float)(distanceFromKSC / maxDist)); The distance is calculated as the Great Circle Distance, with maxDist equal to pi times the radius of the planet.

[tbreimer]

This kind of stinks if you have a spaceplane that just barely doesn't make it to orbit, and it ends up landing on the opposite side of Kerbin.

[Deddly]

2 hours ago, tbreimer said:

This kind of stinks if you have a spaceplane that just barely doesn't make it to orbit, and it ends up landing on the opposite side of Kerbin.

It makes a lot of sense though. Just imagine how much it would cost to recover something that large from half way around the planet. You could always launch a refueller plane and go get it yourself

[jclovis3]

I just tested with two spots on the runway and found you also get 100% in both spots, but right in front of the SPH, you get less. Go figure.

[Deddly]

3 hours ago, jclovis3 said:

I just tested with two spots on the runway and found you also get 100% in both spots, but right in front of the SPH, you get less. Go figure.

Yeah that always bugged me, lol

[Corona688]

On 7/17/2014 at 7:57 PM, Mischief said:

The trick is a new sort of ssto- carry it all to orbit, put a probe on it with a engine just to de-orbit the whole lifter assembly with chutes.

PROFIT!

I built that once, but running the math, it actually cost more to run than my expendable boosters.  The culprit was fuel.  Taking an entire twin-boar into orbit and back isn't cheap.

[suicidejunkie]

On 5/14/2018 at 2:23 PM, Corona688 said:

I built that once, but running the math, it actually cost more to run than my expendable boosters.  The culprit was fuel.  Taking an entire twin-boar into orbit and back isn't cheap.

If fuel cost is an issue, fill the tanks with LFO mined from Minmus before you land.  (LKO gas station doesn't care which way you go after you leave)

[Corona688]

10 minutes ago, suicidejunkie said:

If fuel cost is an issue, fill the tanks with LFO mined from Minmus before you land.  (LKO gas station doesn't care which way you go after you leave)

I was using those lifters to send empty tanks to Minmus, so, catch-22.

Besides - they could hardly land if they were full.  They'd plummet like rocks.

Edited May 16, 2018 by Corona688

[blakemw]

On 5/14/2018 at 9:23 PM, Corona688 said:

I built that once, but running the math, it actually cost more to run than my expendable boosters.  The culprit was fuel.  Taking an entire twin-boar into orbit and back isn't cheap.

That's not my experience. I've generally found that disposable rockets are around 20-30% more expensive than recoverable Twin-Boar SSTO.

 

The cheapest an Orange tank has been put in orbit with a fully disposable launcher is just shy of $30000 (it was mostly kickbacks, with a Poodle core), whereas a Twin-Boar SSTO which cheats a little with SRBs to get moving can do it for around $20000 if the core is recovered at 90% (the cheating is because a full Orange Tank is too heavy for a single Twin-Boar to comfortably lift, a couple of Thumpers or 4 Hammers greatly reduce gravity losses early in the launch and dramatically improve the economics for this particular payload, a SSTO wont tend to be economical if the launchpad TWR is less than 1.4 because too much LF/Ox is wasted fighting gravity). Even if ONLY the Twin-Boar is recovered (everything else is shattered on impact with ground/water) a Twin-Boar SSTO can still be slightly cheaper than the best disposable rockets.

It is important to get a high recovery %age though, if the booster is going to be dropped a quarter of the way around Kerbin you may as well just use Kickbacks.

[suicidejunkie]

23 hours ago, Corona688 said:

I was using those lifters to send empty tanks to Minmus, so, catch-22.

Besides - they could hardly land if they were full.  They'd plummet like rocks.

In that case, why use a booster?

Skipper + Popsicle + nose = SSTO, and then you've got a tank in orbit with no waste. 

If you support it with a single launch clamp on the west side and a small angle tweak in the VAB, then it doesn't even need steering since it will auto-gravity-turn; just use throttle control to make orbit.

[Corona688]

2 hours ago, suicidejunkie said:

In that case, why use a booster?

Skipper + Popsicle + nose = SSTO, and then you've got a tank in orbit with no waste.

Popsicle?

[Pthigrivi]

On 1/7/2015 at 2:24 PM, magico13 said:

It's linear. This is what KCT/StageRecovery use, and without going into too much detail this is also what KSP uses: Mathf.Lerp(0.98f, 0.1f, (float)(distanceFromKSC / maxDist)); The distance is calculated as the Great Circle Distance, with maxDist equal to pi times the radius of the planet.

Is anyone clever enough to produce a map of this?

[Gargamel]

8 hours ago, Pthigrivi said:

Is anyone clever enough to produce a map of this?

I'm assuming it would just look like a target with KSP at the bullseye. 

[Pthigrivi]

6 hours ago, Gargamel said:

I'm assuming it would just look like a target with KSP at the bullseye. 

Yeah I guess it would be interesting to see it scaled and mapped spherically with what percentage returns one could expect depending on where you landed.

[suicidejunkie]

20 hours ago, Corona688 said:

Popsicle?

The big orange tanks.  Rockomax-64s IIRC

[KerikBalm]

Has anyone tested if you get 100% recovery if you land at an alternate launch site? What is the recovery rate at the Dessert Airfield?