[1.12.x] StageRecovery - Recover Funds+ from Dropped Stages

[darthgently]

If I wanted to use SR in the editor as a rough reference for the amount of chute for a craft to parachute down to Laythe or Duna what would be a good rule of thumb?  In other words, if the SR in the editor states that the craft will land at 5m/s, are there factors that others have found I can apply to get an idea of the landing speed on other worlds with atmospheres?

[JedTech]

@linuxgurugamer I've long thought that this mod contains some code that could be really valuable for a stand alone mod. That is a mod that can aid you with knowing if your parachutes will work or not.

As a KSP user, I want to understand how much my parachutes will slow my craft (or stage) down, so that I can design my spacecraft to safely land.


I understand that RealParachutes has a similar feature, but it is not designed for stock parachutes and the stock parachute module. Just something to consider

Edited February 23, 2022 by JedTech

[linuxgurugamer]

On 2/22/2022 at 11:32 PM, JedTech said:

@linuxgurugamer I've long thought that this mod contains some code that could be really valuable for a stand alone mod. That is a mod that can aid you with knowing if your parachutes will work or not.

As a KSP user, I want to understand how much my parachutes will slow my craft (or stage) down, so that I can design my spacecraft to safely land.


I understand that RealParachutes has a similar feature, but it is not designed for stock parachutes and the stock parachute module. Just something to consider

Rather than a complete new mod, possible an option to only be active in the editor and not in flight would do

[eightiesboi]

Hey @linuxgurugamer!

I have a question regarding expectations. I am not reporting a bug. A lifter body with an active probe core and sufficient parachutes (per SR in the VAB) is decoupled with an AP of 200,000m and a PE of 50,000m. There is still fuel in the tanks at the time of recovery, although probably not enough to recover completely without the use of the attached chutes. What should I expect to see when the payload gets out of physics range of the lifter?

1. An attempted powered recovery? (likely unsuccessful, as insufficient fuel remains)
2. An attempted unpowered recovery? (likely successful, as sufficient parachutes exist)
3. Nothing? (No ground intersect, so once out of range, it remains on rails)
4. Something else?

Follow-up question: does SR continue to process for vessels that have been unloaded from prior launches? That is, if I have a lifter that's drifting on rails from a launch of a different (not the current) vessel, will SR process that vessel or is it effectively a ghost ship? If the latter, can I call it and its brethren "The Flying Kutchmen"? 

Thank you so much for the work you do!

PS - I know that FMRS exists and I've benefitted from it many many many times, but I am only curious about SR in this scenario.

 

[linuxgurugamer]

1 hour ago, eightiesboi said:

Hey @linuxgurugamer!

I have a question regarding expectations. I am not reporting a bug. A lifter body with an active probe core and sufficient parachutes (per SR in the VAB) is decoupled with an AP of 200,000m and a PE of 50,000m. There is still fuel in the tanks at the time of recovery, although probably not enough to recover completely without the use of the attached chutes. What should I expect to see when the payload gets out of physics range of the lifter?

1. An attempted powered recovery? (likely unsuccessful, as insufficient fuel remains)
2. An attempted unpowered recovery? (likely successful, as sufficient parachutes exist)
3. Nothing? (No ground intersect, so once out of range, it remains on rails)
4. Something else?

Follow-up question: does SR continue to process for vessels that have been unloaded from prior launches? That is, if I have a lifter that's drifting on rails from a launch of a different (not the current) vessel, will SR process that vessel or is it effectively a ghost ship? If the latter, can I call it and its brethren "The Flying Kutchmen"? 

Thank you so much for the work you do!

PS - I know that FMRS exists and I've benefitted from it many many many times, but I am only curious about SR in this scenario.

 

At what point do you decouple?  On the way up to 200km?  Do you stay with the initial vessel until the lifter body gets down to 50km?

I really don't know, would be interested to hear the results.  You do need to stay with the initial vessel until the lifter body gets recovered or destroyed by the game, though.  On the assumption it's on the way up, I'm not sure what would happen.

[eightiesboi]

2 minutes ago, linuxgurugamer said:

At what point do you decouple?  On the way up to 200km?  Do you stay with the initial vessel until the lifter body gets down to 50km?

I really don't know, would be interested to hear the results.  You do need to stay with the initial vessel until the lifter body gets recovered or destroyed by the game, though.  On the assumption it's on the way up, I'm not sure what would happen.

I will try it and report back. My inclination was to decouple just before transition at 70km, but I could try something else if you'd like me to do so. I am going to predict that "#3 - Nothing happens, because there's no ground intersect and the vessel is on rails" will be the winner. I'm not willing to bet money on it though!  

I'm doing my taxes ATM, so I won't get to play around with this until tonight. But I'll post my results this evening. Thank you!

[DeadJohn]

53 minutes ago, eightiesboi said:

I will try it and report back. My inclination was to decouple just before transition at 70km, but I could try something else if you'd like me to do so. I am going to predict that "#3 - Nothing happens, because there's no ground intersect and the vessel is on rails" will be the winner. I'm not willing to bet money on it though!  

I'm doing my taxes ATM, so I won't get to play around with this until tonight. But I'll post my results this evening. Thank you!

It's going to be #3. KSP deletes debris at 25km and that's when SR does its work. If Pe is 50km your dropped stage will keep orbiting forever without any orbital decay.

[caipi]

1 hour ago, DeadJohn said:

It's going to be #3. KSP deletes debris at 25km and that's when SR does its work. If Pe is 50km your dropped stage will keep orbiting forever without any orbital decay.

I agree with @DeadJohn. If it reenters the atmosphere while you are too far away (might be 25 km as DeadJohn says, but I'm not sure about the exact distance), SR does nothing. I had a couple of stages in an atmospheric orbit (PE in atmosphere, AP above atmosphere). I could watch them on the map enter and exit the atmosphere. Nothing happened even when they had fuel and a command node/probe core. So my bet is #3 as well.

[eightiesboi]

On 3/7/2022 at 7:58 AM, eightiesboi said:

Hey @linuxgurugamer!

I have a question regarding expectations. I am not reporting a bug. A lifter body with an active probe core and sufficient parachutes (per SR in the VAB) is decoupled with an AP of 200,000m and a PE of 50,000m. There is still fuel in the tanks at the time of recovery, although probably not enough to recover completely without the use of the attached chutes. What should I expect to see when the payload gets out of physics range of the lifter?

1. An attempted powered recovery? (likely unsuccessful, as insufficient fuel remains)
2. An attempted unpowered recovery? (likely successful, as sufficient parachutes exist)
3. Nothing? (No ground intersect, so once out of range, it remains on rails)
4. Something else?

Ladies and gentlemen, the results of my experiment:

AP/PE (km)	Decouple below 70km?	Result
200/50	Y	#3
200/50	N	#3
200/20	Y	#1 (pass)
200/20	N	#1(?) (fail)

Parameters of experiment: Lifter with probe core, engine, fuel, and parachutes was decoupled from payload either above or below 70km, as noted above. @DeadJohnwas 100% correct; if the lifter's PE was below 25km, when KSP deleted it as it passed through 25km, Stage Recovery processed it. If the lifter's PE was above 50km, it stayed on rails regardless of the parameters of its "orbit". 

One oddity: when I decoupled the lifter from the payload below 70km, SR recovered the lifter without problem and indicated a propulsive recovery. However, when decoupled above 70km, SR did process the lifter when it was deleted from the game but invariably noted it was destroyed due to excessive speed, as shown here: NB: This was later determined to be due to difference in altitude during the decoupling event.

The only difference between successful recovery and failure that I was able to note was that in each incidence where the lifter was decoupled below 70km, recovery was successful. Likewise, in each incidence where decoupling occurred above 70km recovery failed. In my totally inexpert opinion, I would like to note that the velocity indicated (2276 m/s) looks like the orbital velocity at the time the lifter was decoupled. I would speculate that once you've crossed the border from "flying high" to "in space low", the velocity that SR uses to decide if the recovery was successful changes. However, I may be *totally* wrong about this. NB: I was.

@linuxgurugamer, I hope you find my little experiment interesting. If nothing else, it seems to show that if one wants to use Stage Recovery, one must make certain that any craft to be recovered has a PE (on Kerbin, at least) below 25km. It also may help with successful recovery if the decouple event occurs before crossing the border between flying high and in space low. 

Edited March 9, 2022 by eightiesboi
The cats insisted.

[DeadJohn]

10 hours ago, eightiesboi said:

One oddity: when I decoupled the lifter from the payload below 70km, SR recovered the lifter without problem and indicated a propulsive recovery. However, when decoupled above 70km, SR did process the lifter when it was deleted from the game but invariably noted it was destroyed due to excessive speed, as shown here:

That's an interesting observation.

You were on a 200/20km orbit when you decoupled below 70km. The lifter was still in physics range while in atmosphere. Drag would have cause the lifter's orbit to decay and reduce Ap to something less than 200km. Maybe that was just enough to reduce reentry speed below your Stage Recovery heat settings?

200/20 sounds like too high an orbit for SR to recover with default settings, but all of my recent KSP has been with the JNSQ planet pack so I'm not sure about stock.

 

[eightiesboi]

Just now, DeadJohn said:

That's an interesting observation.

You were on a 200/20km orbit when you decoupled below 70km. The lifter was still in physics range while in atmosphere. Drag would have cause the lifter's orbit to decay and reduce Ap to something less than 200km. Maybe that was just enough to reduce reentry speed below your Stage Recovery heat settings?

200/20 sounds like too high an orbit for SR to recover with default settings, but all of my recent KSP has been with the JNSQ planet pack so I'm not sure about stock.

 

Well, to be fair to by rigidly controlled and fully scientific experiment, my AP was rarely at 200km at the time of decoupling. I was mostly testing for PE, not AP, so the AP varied from a low of 84 to a high of 180 (after decoupling, I targeted the lifter and noted the AP/PE after it left physics range). 200 was the final AP for the payload. However, AP didn't seem to matter at all. The only difference I experienced (again, in my peer-reviewed and journal-ready) experiment was as reported: decoupling events below 70km resulted in success, above resulted in failure with orbital speeds reported in the dialog. 

I am *not* suggesting that anything is wrong with SR, nor that my observations should be taken without a ton of salt. The only thing I *did* do (without being sarcastic) is run the test multiple times, so I am relatively sure that what I observed, on my rig with my modified install, was an accurate representation of how SR works (again though--on my rig with my modded install).

[linuxgurugamer]

6 hours ago, eightiesboi said:

(again, in my peer-reviewed and journal-ready)

Really? 

 

[eightiesboi]

Just now, linuxgurugamer said:

Really? 

 

As long as my cats count as peer reviewers. 

[danielboro]

16 hours ago, eightiesboi said:

Well, to be fair to by rigidly controlled and fully scientific experiment, my AP was rarely at 200km at the time of decoupling. I was mostly testing for PE, not AP, so the AP varied from a low of 84 to a high of 180 (after decoupling, I targeted the lifter and noted the AP/PE after it left physics range). 200 was the final AP for the payload. However, AP didn't seem to matter at all. The only difference I experienced (again, in my peer-reviewed and journal-ready) experiment was as reported: decoupling events below 70km resulted in success, above resulted in failure with orbital speeds reported in the dialog. 

I am *not* suggesting that anything is wrong with SR, nor that my observations should be taken without a ton of salt. The only thing I *did* do (without being sarcastic) is run the test multiple times, so I am relatively sure that what I observed, on my rig with my modified install, was an accurate representation of how SR works (again though--on my rig with my modded install).

no acceleration?
if you wer under constant acceleration then decoupling early will result in less speed and more time for drag.
if 0G all the way ther is still bigger drag the erlier you decouple (large rocket 0 fuel pointy part not look forward)

[darthgently]

On 3/7/2022 at 11:08 PM, eightiesboi said:

One oddity: when I decoupled the lifter from the payload below 70km, SR recovered the lifter without problem and indicated a propulsive recovery. However, when decoupled above 70km, SR did process the lifter when it was deleted from the game but invariably noted it was destroyed due to excessive speed, as shown here:

Given AP and orbital velocity would degrade after decouple while in atmosphere, it would be falling from a lower height at a slower speed on re-entry, so the oddity is in the right direction.  How truly odd it is probably depends on how big a difference in velocity was assumed by SR in the two cases and how realistic that difference was.   But 9.8ish m/s^2 adds up quite a bit so a small difference in AP can make a big difference in vertical speed once you are on the other side of the hill

[eightiesboi]

Spoiler

I was fast asleep, dreaming of Duna, and the giant worms that produce the spice. One swallowed me whole, and I felt a huge weight on my chest, crushing the life out of me. With my last breath, I gasped, "desert power" and startled awake. "That's nice," said my cat, who was sitting on my chest, "but you failed to take into account the altitude of the decoupling event. Also, I'm hungry."

As @darthgentlyand others have mentioned, I was sloppy in my little experiment. I performed it again this morning, making two changes: first, I flew to 66km and made sure I had an AP close to 200km and a PE below 20km (specifically, 198 and 14). Then I quicksaved the game. I then ran multiple tests, decoupling each 1000m (starting at 67,000) up to 74km, checking the SR recovery process each time. And, each time I ran the test, the lifter was successfully recovered.

And so, the "oddity" I noted was due to failure to control for a variable on my part. My cats are ashamed of me, and they've stated it will take many bribes of treats to ever publish in their journal again. 

Everything else I said, however, matches. If you want to use SR to recover a vessel, you must make sure that the PE for the vessel to be recovered is below the point at which KSP deletes it (just under 25km on Kerbin in stock solar system). 

One other thing:

On 3/7/2022 at 9:30 AM, linuxgurugamer said:

You do need to stay with the initial vessel until the lifter body gets recovered or destroyed by the game, though.  

I tried one other little experiment. After getting the payload in stable orbit, but before the lifter was recovered, I switched back to the Space Center, then went to the Tracking Station. I watched the lifter make several orbits, going all the way down to 14km and back up to 198km. Then I switched back to the payload. If the lifter was below the 25km line and thus deleted by KSP, SR *did* process the vessel correctly. So it would seem that you don't have to stay with the vessel after a decoupling event; if you leave Flight, it will be immune from deletion while it proceeds on rails, but when you return to Flight, it correctly gets deleted and SR does work. 

@linuxgurugamerand @magico13make great code. But I think we all know that. 

Edited March 9, 2022 by eightiesboi
I wrote "feet" LOL

[Starwaster]

On 3/8/2022 at 4:24 PM, eightiesboi said:

As long as my cats count as peer reviewers. 

I just have to post this....

[darthgently]

Edited March 11, 2022 by darthgently

[Aelfhe1m]

48 minutes ago, darthgently said:

https://imgur.com/a/RuvmaUS

(I still haven't figured out how to get imgur hosted images to display as an image and not just a link, srry!)

You need the image URL rather than the album. Easiest quickest way I've found in Chrome is to right click the image in the Imgur album page and "Open image in new tab" then copy the URL from that tab. There should be similar options in other browsers.

After that the "Insert image from URL" button should accept that URL for inserting into the post.

[Poppa Wheelie]

It can be done in Chrome with even fewer steps, as follows:

• Right click the image in the Imgur album
• Select "Copy Image Address"
• Inside your forum post, right click and select "Paste"

As I did here:

[Sarah Lafayette]

The mod is currently in 1.12.2 on CKAN.     Will it be updated to 1.12.3? 

Works in 1.12.3 
(changed the version in the version file to be safe, not sure if that's necessary. ) 


 

Edited May 23, 2022 by Sarah Lafayette

[linuxgurugamer]

On 5/5/2022 at 3:14 AM, Sarah Lafayette said:

The mod is currently in 1.12.2 on CKAN.     Will it be updated to 1.12.3? 

Works in 1.12.3 
(changed the version in the version file to be safe, not sure if that's necessary. ) 


 

Not necessary, doesn't hurt

[DeadJohn]

@linuxgurugamer Do you know if powered recovery only works with stock fuels, or does it work with some modded fuel types?

I searched the thread for "lh2" or "hydrogen" and surprisingly had zero hits. I'll probably test Skyhawk Science System with SR, I'm just looking for existing info to inform my test process.

[Aelfhe1m]

@DeadJohn Stage recovery's powered recovery should work with any fuel. Very exotic engines that don't use "ModuleEngine" or "ModuleEngineFX" and SRB's (propellant name like *solidfuel*) should be the only exceptions.

[Ivy]

Is there a setting to disable the in-game notification for stage alerts? It doesn't pop up, but it does spam up the notification log pretty severely. The toolbar button already has all the stage recovery information for the flight, which is enough for me personally.