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Loren Pechtel

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Posts posted by Loren Pechtel

  1. 44 minutes ago, Cheif Operations Director said:

    How do you get the CKAN code off of github and also its saying you needs some Microsoft download. I'm on a laptop I can not download a million things. I can download mods off curseforge. Here is how may directory looks

    When programs want Microsoft downloads the space they take is usually pretty small and it's very likely that other programs will also want the same download.  Since CKAN is a .net executable it's probably asking for a version of the runtime you don't have on your system.  The biggest is under 100mb and will be required to run any .net program targeted on the same version.

  2. 1 hour ago, whitespacekilla said:

    SR relies on some big simplifications for retroburn  and touchdown point. For example, if the stage has control and TWR > 1, StageRecovery simply calculates if you have enough fuel, given mass and Isp, to achieve safe landing velocity, basically checking if a totally unconstrained in terms of time/altitude instantaneous suicide burn at the moment the SR code evaluates the stage would be possible. I think @Starwaster is just saying you could extend simplifications all the way to boostback, even as simple as "boostback costs X in delta v", so you just check for that much after the safe landing deltaV. I know there are more accurate simplifications that could be made but that's a simplification off the top of my head. It ignores characteristics of the suborbital flight path entirely by just choosing some common "median" flight path deltaV. Slightly less simple would be plugging the discarded stage's current velocity into some boostback deltaV requirement function (this is exactly what happens with retroburn, albeit a fairly simple function).

    I understand what he's after.  Unfortunately, StageRecovery is lacking one very, very critical piece of information to calculate the boostback--the point at which the burn could have been done.  StageRecovery could backplot the orbit the object is on but it has no way of calculating when the booster came off.  (Note:  I have used StageRecovery on stages discarded on the way down.  Equip your final stage for recovery, carry enough fuel to get down to a safe velocity and then jettison.  Trying to guide your rocket down to a flat spot is quite a pain, trying to land a booster on ground that isn't nearly perfectly flat is even harder.  I've even built rockets deliberately built to land on their side and watched them go for great long slides on nearly flat ground.)

    If that datum could be obtained I don't think calculating boostbacks would be hard.

  3. Very strange indeed--I was totally unable to get the search to cough up that thread.  The thread listed on CKAN for it doesn't exist so I figured it was one that was lost that day.

    As for the bit about the rocket and page 1--don't you remember the day when all the threads on page 1 of the mod forum got nuked?

  4. 1 hour ago, rmaine said:

    Biggest problem I tend to run into (so to speak) is the Mun. It tends to get in the way and I then have to fiddle to avoid it.

    Yup, the Mun is a pain.  Last I knew at least MechJeb does not handle it well at all.  Check your path before the engine lights, make sure it's clear of the Mun's SOI.  Note that you can have an improper shutdown of the burn if the trajectory temporarily passes through the Mun's SOI.  If this happens simply manually burn prograde and watch the trajectory plot, you'll generally get a reasonable intercept, although not quite as clean as if MechJeb had done it.

  5. 2 hours ago, Starwaster said:

    That's the same as saying that it's too late for a reentry burn but SR calculates that and determines if there is a point to continue trying to recover the craft anyway.

    That's the same as saying it's too late for a landing burn but SR calculates that and determines if there is a point to continue trying to recover the craft anyway.

    And it it meets those criteria THEN it goes on to calculate what the distance from the KSC would have been and calculates what the recovery percent is based on the distance.

    Performing one more calculation to see if it would have had enough fuel to close that distance is no more or less difficult than all the other calculations that went into making recovery possible even though the vehicle was already deemed destroyed by KSP when it was (going by your logic) way too late for recovery.

    It's not that simple.

    There's only a tiny window where Stage Recovery would get control too low for a landing burn.  I'm sure it simply assumes there was enough space (as in reality there would have been, it just would have started before SR got control), the error would be tiny.

    Likewise, a retroburn is no problem.  You won't be too far off if you simply figure it at that point.

    Also, the touchdown point is no problem--simply extend the orbit until it hits the ground, that's your touchdown.  (I suspect it does it without regard for terrain, the discrepancy would be tiny.)

    Boostback is quite another matter, though.  It needs to be performed as soon as possible after the stage comes off.  Stage Recovery does not know where this happened.  When SR gets control it's generally too late for a meaningful boostback burn.

  6. 3 hours ago, Capt. Hunt said:

    I'm not worried about what the spent stage actually does while it's still in physics range (as long as it doesn't explode) I know that SR just runs the math and doesn't actually land your rocket anyway.  @Starwaster has the right idea, it just needs to check if it can do it.  If you want it to actually do a correct boostback, you can use FMRS.

    By the time SR gets a look at it it's way too late for a boostback.  If you want anything sane for boostback you need to trigger it when the stage comes off.  (And note that what I was suggesting was simulating the result, not actually flying the booster back.  The game engine can't even handle flying it back other than with one-at-a-time approach like FMRS uses.)

  7. 10 hours ago, Starwaster said:

    Doesn't matter. Not sure why you're thinking there's some difficulty here but there isn't any. The distance from KSC is already being calculated (necessary in order to determine refund amount) and from there it's just a matter of determining if there's enough delta-v to boost back in addition to the checks made for reentry burn and landing.

    It's just math.

    The distance calculation is fine.  The problem is the boostback burn should be done long before Stage Recovery is triggered.  By the time Stage Recovery wakes up it has no idea of when the stage was jettisoned and thus where the boostback could have been done.  (I have successfully used Stage Recovery on boosters that had been used to fly to the Mun.  Landing the rocket intact was asking for trouble if it came down on land but Stage Recovery doesn't worry about little things like tipping over.)

    The only way I see that Stage Recovery could be made to handle it is if it somehow knew what was supposed to be recovered.  My suggestion:  A recovery controller that's attached to the stage.  When a stage is separated so it has no other control point the recovery controller activates.  It looks at the remaining fuel, allocates what it will need for landing after considering chutes, allocates what it will need to get it down to a safe velocity and uses the remainder to get as close to KSC as possible.  Note that this is not always a boostback, such a system would permit stages to be recovered from in orbit.

  8. 23 minutes ago, Starwaster said:

    No, it just tries to land them where they are. It shouldn't be too hard to do a simple check to see if after deducting enough to decelerate to safe speeds and then to land if there also would have been enough to send it back to the launch site...

    Unfortunately, it's not quite that simple as Stage Recovery is triggered when it goes outside physics range, not when it's jettisoned.  Thus the boostback burn will be calculated at the wrong time.

  9. 29 minutes ago, Bakkerbaard said:

    Bit of a daft question, I suspect, but I need to quit KSP before adding or updating mods, right?

    I've been doing so in the few occasions that I added mid-game, but I wouldn't mind skipping the loading process. Because of all the mods... That CKAN gets me...

    Adding a mod with the game running would be harmless--but the mod wouldn't be picked up until you ran the game again.  Updating a mod with the game running would be a very bad idea.  Even if you didn't get file lock error during the copy you would be asking for it.

  10. On 5/17/2018 at 4:33 PM, Drew Kerman said:

    why? The purpose of this mod is to remove the update notices from other mods for people who take manual control over their mod installs. If you have CKAN then you have a way of being notified when a new update is out - just do the update and you'll never be bothered by AVC messages

    Doesn't this mod also remove the actual update check?  They can be slow if a host is acting up.

  11. 8 hours ago, NorthernBruce said:

    @Bakkerbaard

    What's worked for me with big poorly streamlined loads is to fly vertically to about 20K and then start tipping over into a gravity turn. Air effects seem to reduce around that height.

    Yup, this is my experience, also.  Make it as symmetric as feasible, get the COM in line with the rocket and I haven't found anything I can't fly with using a very steep trajectory in MechJeb.  Costs fuel but it gets the job done.

  12. 3 hours ago, Nich said:

    Hi, I am trying to get my RP-0 recovery rocket working.  I have an RD108 core with 2 AJ-10 (MID) engines to decelerate and parachutes for landing and a THOR Avionics for control and 800 electric charge.  The AJ-10s have 1550 dv.  When I fly the rocket by hand everything works.

    When staging I set throttle to 0 and activate the AJ-10s

    Stage recovery says the stage burns up in atmosphere at 3200ish m/s

    Are the AJ-10s not supported?

    Is the TWR to low?  I know I have to start my burn at about 90k when flying manually.

    Am I not allow to mix fuel types?  Do I need to place the AJ-10's first?  How does this work with sub assemblies?

    3200m/s will fry the rocket every time--that's above Kerbin escape velocity.  You'll need to edit the config as you're obviously using a different world.

  13. 4 hours ago, Zafer Altan said:

    I downloaded the mod, and it doesn't work quit well i drop a stage, and it gives me a message that it is recovored but i do not have the button where you can see all your recovored vessels.

    When you recover a vessel you simply get back a percentage (based on distance) of the value of whatever it was made of and any kerbals and science.  There are no "recovered vessels" to examine, same as with the stock game.

  14. 31 minutes ago, BUGescape said:

    Thank you. I did leave 1500m/s dv of fuel and stage them manually: I throttle the engine to 0 and stage, and move my focus to upper stage.

    With this, it should at least have some hint in the stock message, but no, it just says: 'stock module used' :(

    Thank you.

    It works like that before, when I did not implement any sort of recovery tech, some message with pop up like 'stage burn up, did not find a point of control, try to add a probe on it'....

    But this time it just says 'stock module used', 'destroyed xxx km from ksc'...

    SR has long been weak in telling you why it went wrong.  However, from your pics I'm pretty sure it failed to find either parachutes or active engines.  Since I saw no fuel going splat I suspect that's the problem.

    Putting the landing fuel in a separate tank and locking it so it won't be burnt on the way up makes life much simpler.  Simply stage your rocket normally when it runs dry, nothing fancy needed.  (It even works with MechJeb and hands off the keyboard.)

  15. 10 hours ago, BUGescape said:

    Sorry for the album thing...

    So you mean powered recovery is currently unsupported? I run ksp 1.3.1 and stage recovery v1.7.2

    BTW just want an automatically powered recovery experience, but FMRS required manual handling isn't it?

    I can't address currently--I've been waiting on some mods and haven't updated.

    However, I have successfully done powered recovery.  I added a probe core and a small fuel tank that I locked that had enough fuel for about 300m/s.  Booster recovered successfully.  You need a pretty big booster before powered recovery is a better deal than chutes.

    As for your photos:

    After fixing the URLs (you have the first part duplicated) I see a rocket that in the VAB shows as it's going to lithobrake and in flight I see a rocket that did lithobrake.  The list of components isn't quite complete but I see no fuel--and without fuel there can be no powered recovery.

    The safe way to do powered recovery is a locked fuel tank with enough fuel for the landing, but I see nothing in your rocket that looks like this.  The only other way to do it is to jettison it manually at the requisite fuel level (and note that getting this right is hard as it's such a small amount compared to the total it was carrying!)  Note that jettisoning a stage does not shut down it's engines, you must do so manually.  (I've had a MechJeb screwup result in a staged but still burning engine pushing me into space!  Flies fine until you attempt to turn and since it's staged you can't shut it down.)

    I also note the presence of grid fins and landing legs.  You might be including these for thematic reasons but they are not needed for Stage Recovery.

  16. 2 minutes ago, BUGescape said:
    Hi magico13, I got some issues here with stage recovery, could you have a look?
    I tried powered recovery with this vessel:
    Album https://imgur.com/UdRMY4J will appear when post is submitted
     
     

    I tried to recovery first stage, in order to get stage recovery involve I add a booster on top so my focus view can fly far away and let stage recovery kick in. I left 1500m/s dv in first stage.

    Well originally stage recovery says no...it doesn't think it can be recovered, with a short of 200m/s dv. I have control installed, omi antenna, battery, SAS, just don't know why it doesn't calculate for powered recovery.

    During actual fly (Krash test simulation mod), it just says so:

    Album https://imgur.com/i4Fc8ag will appear when post is submitted

    "Stock module used"

    Not sure what it means. For those previous uncontrolled decoupled stages, stage recovery at least gave some hint about what caused the stage destroyed.

    Wondering what is wrong here, can anyone give me some hint?

    Here is the ksp log file. I got a lot of mods installed but I don't think there is any mod interfering the stage recovery. (Krash mod might, but I don't know)

    https://www.dropbox.com/s/feh53k5xxfu3v3m/KSP.log?dl=0

     

    You can do unpowererd recovery even if you don't get far enough away.  I've dropped asparagus stages less than 1000m up, it works (and gets a very nice recovery percentage.)  Note, however, that while Stage Recovery only requires the presence of sufficient chutes you have to be more careful with such low-dropped stages--the chutes must be correctly set up or the stage will execute a lithobraking maneuver before it goes outside physics range.

    Powered recovery is another matter, a dropped stage can't light it's engine while you're controlling the main rocket.  Thus you have to use FMRS.  I've never played with this, I've never built something that was big enough to want powered recovery but dropped low enough that Stage Recovery couldn't handle it.

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