Recovery Transponder Fitting strategy: does it ever pay? (answer: no)

[numerobis]

I eagerly picked up recovery transponder fitting, because I often land a few km from KSC. I'm confused though by the numbers I'm seeing: launch costs are up 6%, so when I launch, my rocket (or more likely my plane) costs 6% more than normal. Fine. Recovery is up, so when I recover, I report 100% recovery when landing on the KSC grounds, as opposed to 96-98% in my normal landings. But it seems to be reporting that e.g. my radial air scoops recover at 1,000 Roots -- even though, with the 6% extra cost, they cost me 1,060 Roots to launch.

So whereas each scoop before was costing me 20-40, now they cost me 60. It's break-even when I land my scoops at a distance with 94% recovery. But there's parts that I don't recover (the fuel, for example), despite having paid for transponders (flammable transponders?) which means I only gain from the strategy if I land fairly far from KSC, where I'd normally get 90% recovery or so -- and that's with an almost fully-reusable spacecraft.

With the strategy at lower settings, the transponder cost goes up, and the benefit goes down, so that at low levels you lose no matter what. And if you're dropping a first stage, I have trouble making things end up in our favour ever.

Am I misreading what's going on, or is this a seemed-like-a-good-idea strategy?

Edit: consensus seems to be NO, recovery transponder almost never pays.

Edited November 19, 2014 by numerobis

[Taki117]

I think this is a "Seemed like a good idea" strategy, if you use mods like Debrefund it should take that recovery into account.

[tsotha]

Isn't this one of those strategies that only really works when you max it out?

[RainDreamer]

I thought that strategy is actually for those that either can't or not bothered to land close to KSC? It is even said to be used for recovering stuff half way around the planet in the description.

If you can land close to KSC reliably, something to reduce launch cost seems better.

[AlexinTokyo]

I use this strategy on my career mode for two reasons:

1. It means I can miss KSC by quite a large margin and still get OK fund recovery. Since I use the Trajectories mod, this isn't much of a benefit for equatorial orbits, because I can pretty much pinpoint the landing site, but it's nice for saving time with inclined orbits which don't pass directly over KSC every revolution.

2. TNSTAAFL. Because of the 6% difference between launch cost and recovery value there are no longer any free parts (launch clamps, for example, cost nothing unless you use this strategy), and testing parts or vehicles on the pad also has some cost, which provides an incentive to optimise testing programs.

The real advantage of this strat is for people who can't, or won't land at KSC. If you land somewhere you'd normally get 15% value for recovered parts, this strat will literally double the amount returned.

[Claw]

Personally I also agree that this strategy doesn't really make sense. You will literally never benefit from it. Ever. Well, maybe not quite "ever," but you'd be hard pressed to get an advantage. Even if you land at the far side of the planet, recovery value is 50%. Practically speaking, you really only benefit from recovering craft that are extremely fuel efficient, and they need to be about 1/5 of the way around the planet or further. Anything recovered closer to the launch pad suffers more loss of funds.

And if you launch, realize you need to change something and recover, you lost the 6% investment (you can never recover for more than 100%, even if it costs 106% to launch). While as AlexinTokyo points out, that would be akin to losing funds on a scrubbed launch, that doesn't make sense to me from a voluntary strategy standpoint. I would think that if it's a fund penalty you want, there are probably better ways to get it.

Cheers,

~Claw

[KerikBalm]

Hmmm, I didn't realize that you don't get the added cost back when you use this strategy.

I thought recovery would be equal to: (Base part & resource cost)*(launch cost modifier) * (Max: [1, recovery%/100%])

Recovery amount needs to be multiplied by the launch cost modifier.

Even then... I use a lot of SSTOs that launch payloads that are never intended to return.

Even if I could get 100% recovery (as opposed to 100/106) instead of 98% on the launcher, if the payload costs as much as the launcher, and it costs 6% more, then I've lost money.

Its also no good for staged designs: if the final stage is 10% of the cost of your entire rocket, getting a 15% recovery bonus on 10% of your rocket cost does not offset a 6% higher cost on the entire thing.

[numerobis]

I thought the same as KerikBalm until I noticed funds falling while I was testing my plane.

If the final stage is less than 40% the price of your entire craft, you lose, guaranteed: if x is the cost fraction of your return stage, you need .15*x > .06, which means x > .06/.15 = 40%.

If you have any aim whatsoever, you can land in an area with better than 85% cost recovery. Land in an area with 90% cost recovery normally (100% with the strategy) and it pays off only at .1*x > .06 = 60% of the launch cost needing to be recovered.

At low levels, you lose no matter what: the transponders cost 9.8% and recovery improves 5.5% (if you land far), so it only pays off if you return .055*x > .098 = 178% of your spacecraft has to get recovered. Which would be a neat trick.

[KerikBalm]

Seems to me that the way to fix this, is to have it only add X% to the cost of "command modules" - ie probe cores and capsules.

- or just a fixed cost (ie, 500 funds per launch)

Basing it on the cost of the entire rocket just makes it a losing proposition in almost every reasonable scenario