Rescue Missions or Refuel Missions?

[steedcrugeon]

I'm curious as to the general consensus of the question. As a rule (if you have one) do you try to rescue the crew from a stranded ship or do you attempt to salvage it, and drag it back across the system?

My present situation, which brought about this query, is that I have embarked on my first manned Duna Mission, in a vessel which had sufficient dV to get to Duna orbit and back from LKO. Unfortunately my trajectory was interrupted by the rude arrival of Minmus SOI which then required some 444m/s delta-V to correct. This will result in the vessel having enough fuel to get there but not get back now.

I have a lander arriving separately prior to the main ship (autonomous delivery) so I'm already planning 1 rendezvous, but I'm weighing my options to see whether I leave the original vessel as a temporary station on Duna orbit or bring the whole thing back. This is a science game (I have been playing maybe a month or so now) and haven't realised all the tech yet so no nuclear drives, everything LFO at present.

So to the original question, do you guys and girls tend to bring back everything you can or do you start little 'Stations of Opportunity'?

Gratuitous vessel in question screenshot:

[Magzimum]

I bring back my Kerbals at any cost.

I bring back the science if it is cheaper than launching a new mission. (I play career, so funds are important).

I do not care about the ship.

Often, I construct my ship so that I can disconnect the Kerballed pods/habitats and science from the rest of the ship, so that a rescue vessel can drag home only the important bits.

[steedcrugeon]

@Magzimum oh I definitely meant on the kerbals returning (I'm running USI life support mod and have set them for MIA/KIA should supplies be depleted) I have lost 3 kerbals in the save so far and I'm determined not to lose anymore.

I really like your idea of having detachable hab sections fro separate recovery, I think I'll use that in future mission.

Edited September 5, 2016 by steedcrugeon
typos

[Magzimum]

In addition to the previous comment, I often equip the pods/habitats and science with a heatshield and parachutes, so that it can land itself on Kerbin. The stack looks like this:

• [Kerbals]
• [Science, batteries, parachutes]
• [heatshield]
• [docking port]
• [docking port]
• [ship (fuel, engines, stages, more batteries, solar, etc.)]

This way, if the mission goes according to plan, the important bit can land safely. If the mission goes wrong, I can send a rescue mission. Because I can just dock the top section to the rescue vessel, it keeps the rescue mission very simple.

The same idea makes it possible to recycle the ship too. In the few cases where I went nuts properly Kerbal on a mission, and I built a giant mothership, the same strategy allowed me to dock and undock the top section with the Kerbals and science.

[Sharpy]

That depends on the state of the vessel.

It's rarely the delta-V that gets me. I tend to overengineer my craft in that respect - it seems my unkerbed mission to Eeloo will be actually a science return mission, seeing how I'm hauling the launch stage's Twin Boar to Eeloo along with the probe, with enough delta-V to do the capture burn, while the transfer stage will be used as the landing stage, and possibly launch stage ... how in the world am I going to stick a landing on the nozzle of LV-N?

Anyway, the kerbals either just wait for a rescue from something that happens to pass by, or fix it themselves.

[eddiew]

18 minutes ago, Magzimum said:

• [docking port]
• [docking port]

I think you just changed how I build rockets forever...   Do you just accept that the docking port will burn up on re-entry, and does it ever damage the ship?

As for rescue vs refuel; depends. Most likely the ship will be broken, and most likely it is the engines that broke on landing, so just the crew+data is fine. In the (very unlikely) event I didn't pack enough fuel, then refuel. This has never happened with a manned vessel, but I did have a probe that simply couldn't get home - with the result that after hours of failing to gravity assist my way out of the problem, I took it somewhere else instead  

Spoiler

...thought better of it the next day and ret conned...

 

Edited September 5, 2016 by eddiew

[Magzimum]

26 minutes ago, eddiew said:

I think you just changed how I build rockets forever...   Do you just accept that the docking port will burn up on re-entry, and does it ever damage the ship?

As for rescue vs refuel; depends. Most likely the ship will be broken, and most likely it is the engines that broke on landing, so just the crew+data is fine. In the (very unlikely) event I didn't pack enough fuel, then refuel. This has never happened with a manned vessel, but I did have a probe that simply couldn't get home - with the result that after hours of failing to gravity assist my way out of the problem, I took it somewhere else instead 

Oops, no it does not explode under my ship. I put a decoupler in between. I don't like explosions upon re-entry.

• [Kerbals]
• [Science, batteries, parachutes]
• [heatshield]
• [decoupler]
• [docking port]
• [docking port]
• [ship]

Other variations are possible too. But the general picture is that the Kerbals and the science can be landed safely on Kerbin (have heatshield and parachutes), and can be transferred between ships through regular docking ports, preferably in such a way that it does not wobble with engines on (so, preferably large docking ports).

Another favorite method is to put the docking port at the top, and put a nosecone directly on top of the docking port:

• [nosecone]
• [docking port (facing towards the nosecone)]
• [Kerbals]
• [Science, batteries, parachutes]
• [heatshield]
• [docking port, facing the heatshield]
• [ship]

This works especially well with the lander cans which do not get more narrow towards the top (thereby forcing you to use smaller docking ports, which will wobble more). The docking ports can act like manual decouplers. The nosecone is discarded anywhere above 50km altitude.

[eddiew]

1 minute ago, Magzimum said:

Oops, no it does not explode under my ship. I put a decoupler in between. I don't like explosions upon re-entry.

Ahh, gotcha   With 2.5m tech, I guess there's also an option for two back-to-back docking ports, which is probably a lot lower profile than that big decoupler ^^ 

[Magzimum]

6 minutes ago, eddiew said:

Ahh, gotcha   With 2.5m tech, I guess there's also an option for two back-to-back docking ports, which is probably a lot lower profile than that big decoupler ^^ 

True. You'd need 3 in total for this to work: one facing up to the heatshield. This acts as a decoupler and will only undock upon re-entry. And two docking ports facing each other below that, for regular docking and undocking.

Personally, I didn't think all of this was rocket science, but I appreciate the positive feedback on my post(s).

I hope it helps @steedcrugeon too!

Edited September 5, 2016 by Magzimum

[steedcrugeon]

@eddiew I have re-purposed/re-tasked probes in the past which had additional dV in much the same way. Enjoyed seeing who you laid it out though, nicely done.  I've adapted this approach now in so much that my autonomous Duna lander delivery vehicle doubles as a SCANSat, if there is sufficient dV after it's rendezvous (extra probes are useful to a point I find).

@Magzimum detachable docking ports through a heatshield, how novel! This will most definitely change how I construct my long range missions, I love the 'stellar Life-boat' kind of philosophy.

[Brainlord Mesomorph]

After the first Mun landings everything I send up is designed to be multi purpose/multi use. So for me always refuel.

that said, if it was designed to be a single purpose disposable vehicle, then just get the crew (and the science)

[Superfluous J]

Anything big enough to leave Kerbin's SOI gets at least one docking port, unless it's the simplest "Apollo Style" mission and those generally have them because I'm leaving an orbiter anyway. For those, I generally tend to try to refuel.

[Magzimum]

Here's a typical lander+mothership design I use. (In this case the mothership is heavily overdimensioned for a Duna-Ike-Mun-Minmus flyby mission, where the lander is only for an Ike landing).

In this case, the mothership had about 3000 dV left when it got back to Kerbin (did I mention it was overdimensioned?), but in case it had gone wrong, that lander could just disconnect, and attach to another rescue vessel with either the lower docking port (large), or the one on top (regular). Likewise, the mothership has additional docking ports, because if you haul 35000 units of fuel, it really does not matter if you add 1 ton worth of docking ports in various sizes. Combining 3 missions makes so much cash I could build this

This mothership is obviously more likely to become a rescue vessel for a less extravagantly fueled mission than to run out of fuel itself.

Edited September 5, 2016 by Magzimum

[Francois424]

I don't like leave "debris" behind, I'll usually evacuate the personnel, and give the "debris" enough fuel to crash it somewhere (say into Jool if in the system).

My stations are meticulously planned, and each panel is installed by experts to make sure of the highest quality possible.
Making makeshift stations seems... unlikely.  But I've still done one or 3, especially in Jool.

Full refueling is performed when the ship is deemed re-usable and will be used for another mission.

[juanml82]

Well, a ship designed to return just the crew and science will be smaller than a tanker. OTOH, if you're setting up a mining rig in Ike at some point, the tanker can remain in Duna to assist any further missions

[septemberWaves]

I tend to test things extensively so that recovery missions are not necessary; particularly with vessels that I'm going to be posting on the forums. For example, all of my standardised non-recoverable launch systems cannot fail so long as the payload is within the intended range and the staging was set up correctly, and my interplanetary vessels will always have plenty of delta-v for their intended destination and cargo, and often have additional delta-v on top of that in case of any errors. In fact, lately I've been re-engineering some of my interplanetary transports so that the rescue portion of a mission is integrated into the command section of the vehicle in the form of an escape pod system. It does slightly raise the mass, but it ensures that the crew can always get home even if (in some incredibly unusual and unlikely circumstance) the rest of the extensively-tested and highly-redundant vehicle fails.

That being said, my Organa-class transports have an extra emergency feature in that they have the thrust required for a powered landing on Moho (and therefore on at least one celestial body in every planetary system that I know of). In this instance, the vehicle would reach about a meter above the ground and zero out velocity, drop the crew section (since the Organa-class transports have the crew module at the rear and can't stay upright) and then the propulsion and service modules would ascend and travel a few kilometers away from the jettisoned crew module for a safe impact. The crew would then remain on the surface until another transport could be sent to pick them up. However, this sort of rescue situation is unlikely to ever be necessary, because of the amount of testing I put in to ensure that my vehicles work perfectly.

Edited September 5, 2016 by eloquentJane

[nascarlaser1]

If your ship has docking ports, and if unlike me your good with docking, you can dock a rescue ship, then send a second mission to try and recover the actual ship. This way, you've made sure the pilots will live to fly another day, and you also can try to get back the shuttle, but if you fail no one will die in the process (I recommend making the second recovery shuttle unmanned, incase you need to crash it into the sun ).

[steedcrugeon]

12 hours ago, Francois424 said:

I don't like leave "debris" behind, I'll usually evacuate the personnel, and give the "debris" enough fuel to crash it somewhere (say into Jool if in the system).

My stations are meticulously planned, and each panel is installed by experts to make sure of the highest quality possible.
Making makeshift stations seems... unlikely.  But I've still done one or 3, especially in Jool.

I've taken the 'responsible debris management approach' which mean I now plan that anything which achieves orbit can be forcibly deorbited (add probe, and mono prop - I don't have the seperatrons yet but that's the preferred options).

My stations are also planned, I'd like to say meticulously but I just lot them down on paper and do a few calculations to make sure that the payload distribution is relatively even and the CoG when constructed is not in the wrong place.

 

10 hours ago, eloquentJane said:

I tend to test things extensively so that recovery missions are not necessary; particularly with vessels that I'm going to be posting on the forums. For example, all of my standardised non-recoverable launch systems cannot fail so long as the payload is within the intended range and the staging was set up correctly, and my interplanetary vessels will always have plenty of delta-v for their intended destination and cargo, and often have additional delta-v on top of that in case of any errors. In fact, lately I've been re-engineering some of my interplanetary transports so that the rescue portion of a mission is integrated into the command section of the vehicle in the form of an escape pod system. It does slightly raise the mass, but it ensures that the crew can always get home even if (in some incredibly unusual and unlikely circumstance) the rest of the extensively-tested and highly-redundant vehicle fails.

That being said, my Organa-class transports have an extra emergency feature in that they have the thrust required for a powered landing on Moho (and therefore on at least one celestial body in every planetary system that I know of). In this instance, the vehicle would reach about a meter above the ground and zero out velocity, drop the crew section (since the Organa-class transports have the crew module at the rear and can't stay upright) and then the propulsion and service modules would ascend and travel a few kilometers away from the jettisoned crew module for a safe impact. The crew would then remain on the surface until another transport could be sent to pick them up. However, this sort of rescue situation is unlikely to ever be necessary, because of the amount of testing I put in to ensure that my vehicles work perfectly.

I see, this definitive testing is definitely the ideal approach as I, and probably others like me, are less polished and experienced when I discover tools like the transfer window planner and do some kerbal like number crunching to find that our Minmus research vessel has the minimum requirements to deploy to Duna with a launch window only 4 days away events often unfold in interesting fashion, capitalising on the situation so to speak...

[septemberWaves]

3 hours ago, steedcrugeon said:

II see, this definitive testing is definitely the ideal approach as I, and probably others like me, are less polished and experienced when I discover tools like the transfer window planner and do some kerbal like number crunching to find that our Minmus research vessel has the minimum requirements to deploy to Duna with a launch window only 4 days away events often unfold in interesting fashion, capitalising on the situation so to speak...

Generally I ensure that all of my large vessels ("large" meaning anything over 75 tonnes) with a destination outside of Kerbin's SOI have at least 1km/s more delta-v than they need. That way, if I make a mistake or slightly miss a transfer window, a 400m/s correction burn isn't out of the question (though I believe the worst one I've had was only about 250m/s).

[Kamuchi]

Recovering stranded ships has always been the stuff I`ve had the most fun with due to that it`s all unplanned, unpredictable and goes as it goes unlike anything else you do in ksp  

[DunaRocketeer]

I either have an on board mining/storing/refining capability, or the destination base has the same capability. This is necessary since most of my vehicles are not capable of returning without a refuel.

[suicidejunkie]

There is a third category when you have KAS; repair missions.

After a hard landing, a design flaw discovered in the field, or a launch fumble, the vehicle in question can sometimes be repaired independently by the engineer, but often requires spare parts to be shipped in.  This is not a rescue mission, just a mail-order shipment.

 

Refueling is always a semi-planned thing for me; if fuel is low, then I will make a small detour to tank up at the local station and then carry on.  My ships all have dV to spare.

The only time I've ever made an emergency delivery it was more a matter of delivering oxygen and water than fuel, and what fuel was needed was because of the 800m/s emergency burn to make it to Minmus before the Ox/H2O hit zero (and the subsequent need to stop at the end before going to Kerbol orbit).

 

Real rescue missions have been relatively rare, although I'm discounting a few that might typically be considered rescue missions...

For example, Valentina's 3-parts-left capsule getting piggybacked on the top of the mun miner after she used the other 90% of the vehicle as a crumple zone when she ran out of fuel doing a suicide burn...  the original plan was to use the miner's fuel to get her back home, and it was a minor tweak to the plan to use the miner's engines as well.

[Terwin]

I have had a number of refuel missions, but surprisingly few rescue missions(I blame F9)

Last night I had my Ike fuel station launch and grab my Duna Scansat to top off it's tanks(taking them both back to Ike as I think it will take a second trip and I have already finished scanning Duna, so no need to keep that orbit)

Last weekend, I discovered that my Moho fuel station did not have enough d-v to capture at Moho, so I diverted it to Eve where it is awaiting the Gilly fuel station's arrival(not enough fuel to get to Gilly), unless my manned mission get there first, in which case it may be fueled with ore harvested from Ike so it can land and refuel on Gilly before heading to Moho where it will act as an autonomous mining/refueling station.

 

I have had a number of early-career missions which required a tanker deliver the fuel needed to get home.

 

On occasion, I have had vessels end up on their sides, but I always restored an earlier game unless I could get it back into orbit from that position.

(much more often I misjudge something and there is not enough left to rescue, and for those I always restore an earlier game, as I do not let my Kerbals stay dead)

[Corona688]

I've been getting better at hauling entire ships...  A fuel plant on minmus filling autonomous orange tanks lets me get away with more dv.  whoops, the mun rescue doesn't have enough fuel?  send Tanker #3 that way and do a rendezvous.  I've also got little robots to grab and reposition things so the real lander can pick them up more easily.  Sometimes used in pairs even, rough grab, reposition, fine grab.

What's hurting right now is the lack of an orange-tank equivalent for pure LFO.  Trying to make do with mk2 fuselages.

Edited September 9, 2016 by Corona688

[Hodari]

Why choose one or the other?  The true Kerbal way is to send a rescue mission, then send a refuel mission since the rescue craft also ran out of fuel, then send a second refuel mission since the first refueler also didn't have enough fuel and had to take some of the fuel that it was originally bringing to refuel the other vessels with and use that fuel instead just to get there...and finally send another rescue mission to bring back the crews of the refuelers.