Saving money on career mode?

[Colorjuice14]

Would it be cost effective to attach parachutes to engines/tanks you intend to eject in one of your rocket stages and recover them? Or does it give no value since the tanks are empty?

[edorward]

The motors and the tanks are valuable, but the calculus is whether the added cost of parachutes is worth the diminished return you get from recovering away from the KSC times the value of the stage itself. Also - and correct me if I'm wrong, experts - if you aren't actively flying the stage or within physics range and the craft is labeled "flying", the game deletes it. That would make it really hard to recover SRBs, for instance, but you might have a chance to recover your primary first stage if you jettison it very close to your orbital insertion burn.

[Chibbity]

You are correct, anything outside of the active physics bubble that isn't being actively controlled, and isn't on a stable orbital trajectory is assumed to be lost and deleted.

There are a number of mods that address this issue in varying ways.

[MiB]

You should use Stage Recovery Mod. It saves a bit of cash depending on speed and distance from KSC
UPD: here is the link for its page on KSP forum
https://forum.kerbalspaceprogram.com/index.php?/topic/78226-14-stagerecovery-recover-funds-from-dropped-stages-v180-march-11-2018/

[andylaugel]

Automatic deletion of parts on suborbital trajectories shortly after leaving your 2.2 km physics bubble makes that kind of stage recovery unreliable.

It is possible to build a single stage to orbit (SSTO) spacecraft that delivers a payload into orbit, returns to Kerbin's surface, and gets recovered. I recall I did some experiments along those lines a couple years back, and here are the key points I recall:

• Your SSTO will be heavier and more expensive than one or more disposable stages. It needs to put the payload and itself into orbit, and have enough fuel to deorbit itself afterwards. It'll also need a control pod (and any power generation & storage & antennas it needs), parachutes, and so on.
  
• The SSTO's return value is based on how close to KSC it lands. You'll want to learn precision landing to make this cost effective.
  
• Your SSTO will lose value if parts explode on re-entry and/or landing.
  
• Recovering the SSTO requires your real-life time and attention. Ask yourself if this going to be fun for you?
  
• Experiments showed me the net difference in cost is negligible, and which is better for you boils down to your design and piloting skills.

[f_m_85]

Wasn't putting a probe core on top of the tanks a reliable way to prevent deletion, because that way it is considered a craft after decoupling?

[Chibbity]

Originally posted by f_m_85:

Wasn't putting a probe core on top of the tanks a reliable way to prevent deletion, because that way it is considered a craft after decoupling?

No, being debris or a craft isn't the issue.

Anything leaving the active physics bubble inside the atmosphere is deleted. No exceptions.

[nikolai]

Originally posted by MiB:

You should use Stage Recovery Mod. It saves a bit of cash depending on speed and distance from KSC

I would second the Stage Recovery Mod. It works well in real practice, modeling returnabe stages. 2 km/c max air speed plus default limits on touch-down speed (variable 6-12 m/s) work awesomely and suffiently "Kerbalistic".

[nikolai]

Originally posted by Chibbity:

Anything leaving the active physics bubble inside the atmosphere is deleted. No exceptions.

Stage Recovery Mod intercepts the deletion request and performs it's own basic modeling of what's going to happen. Including
1) simulated parachute deployment (definetly works),
2) powered descent (supposed to work with probe + engine + some fuel)
3) heat shield abblator application to prevent burn-out when overspeeding

#1 definetly works even in Real Solar Sustem / Realism Overhaul / RP-0 combinations. Parachutes are what I use for my booster or stage 1 needs.

#2 and #3 anekdotaly supposed to work and I saw them coded in the mod, but most likely only work with stock engines, fuels and heat shields. Have not use that succesfuly (since I mostly play RSS for extra chalenge), but feel free to try lastest builds.

[nikolai]

Another hard-core way of saving stages is using FMRS Mod https://forum.kerbalspaceprogram.com/index.php?/topic/157214-141_-flight-manager-for-reusable-stages-fmrs-now-with-recoverycontroller-integration/

This mod allows to split time in parallel lines, allow you to control all parts of the split aircraft, and then merge the landing outcomes.

Imho, for basic booster stages, esp Solid Rocket Boosters this is just too much work for very little fun. Boosters tend to be rather predictable in low atmosphere and easier to save with Stage Recovery Mod.

At the same time, second stages that travel faster that 2km/s or really-complicated aircraft-like first stages with jet engines is something that might be fun to land with FMRS.