Muetdhiver

oO I missed that. Clever. I will do an updated dV budget with guesses for LIMA & KILO at 2.5t and 1.2t respectively.

I think that given that we have a nice 80x80 orbit, we could detach MIKE's top tank. Just be aware that MIKE alone has no probe core (saves weight, and we'll have plenty of those on bord anyway). Two questions : 1) I saw that TANGO has a bottom docking port (which is nice). Does it block the spark thrust or not ? 2) It would be nice to have LIMA and KILO masses to get the final dV budget. (And see if we need extra fuel tanks or not)

So I created a pull request. It's a bit of mess because I'm a complete github noob. I'll let you check it MIKE is in 70x120 and has 78 m/s dV of manoeuvre fuel left. => Badge : Jool 5 Badge with a trilobite or caveman instead of the kerbal ?

TBH with MIKE I was only concerned with getting it in orbit. At the moment it is 80x120 but it has a bit of manoeuvre fuel left. 80x80 might be possible. I have an imgur album with the pics. It's my SOP for all missions. I will try to make the pull request as soon as possible. Next step will be adding the fuel with the four tenders I suppose. Who's up ?

I have assembly pictures. Quite a few, since I had to try the assembly 3 darn times before getting it to work XD For the top tank it's a really simple trick : launch the bottom part & park it on the crawlerway. Then launch the upper part (held by clamps). Roll beneath it, couple by detaching the upper part from the clamps. In principle you could build a rather high stack that way, and it's mch easier than docking lateral boosters. The problem it gets all wobbly. And yeah, the side boosters help a lot wrt to rigidity, but detaching them is bug prone. One thing I realised is that only having reliants for the boosters is not that great. My TWR at launch was really poor, and the poodle is only used above 10km. With making history one could make bobcat based 1.875m boosters that would have way more TWR and control authority. The neatest trick in all of this is using fairings truss as structural elements : lightweight and very rigid, they are just perfect. I was able to put more fuel in the boosters that way. It's becoming one of my favorite Caveman part along with the magical 1.25 payload bay. I have started an NCD run a while ago with MH, but between on-pad assembly and the new nav tools, I will certainly go back to it since it opens up new possibilities (I got demotivated upon reaching the "Minmus science farming" stage, as I was not too keen on grinding my way through NCD, but now I could try to go early interplanetary with way less margins, i.e. before Jr ports.)

MIKE test complete ! TBH, this rocket is a pile of junk, and a major pain to assemble.... I seem many flying turds but this one takes the cake. Gravity turn not before 25km, if the boosters undock get messed up, save & load. Aim for Ap 120, or at the very least 110, or you'll fall back down. Just enough fuel to get in LKO with the payload. Complete lemon, but does the job anyway. TBH I would not mind if I could not have to redo it XD how can we do to use my save so that we don't repeat the exercice ? I'll put everything in the repo in any case tomorrow.

I should be able to do a full on-pad assembly test of MIKE along with a launch test. One thing that has been bothering me is the dV budget required on the mothership. I think that adding an extra 3T of fuel fo use in the Jools system is 100% necessary (so that we can deliver 2x TANGO with ease to low Tylo orbit) The way I see it, MIKE should be packing about 3K dV. So, that would mean 2K for the ejection, 200 for the correction burn(s), 200 for high eliptical Jool orbit. That leaves about 600 for use & safety, which is enough for a Tylo intercept. 2x TANGO + 3T of fuel to low Tylo orbit as planned will work fine as a 3T tank should provide in the ballpark of 1600 dV with 2x TANGO attached. My concern is for the delivery of KILO+LIMA to Laythe. A possibility could be to use the reamining MIKE fuel once all the 3xTANGO and the extra 3T of fuel are detached. This is about 9 Tons of payload, so once it's dropped off, we would recover a bit of dV from the reduced dry mass (assuming 200 m/s remaining before drop, we would go back up to about 400). We could also attempt a grav assist from Tylo to boost Pe from low Jool orbit to Laythe orbit (since we have to get close to it anyway), but that will not be an easy task to pull off (esp. in caveman), but it would save about 500 dV. If I see things correctly the most economical (and risky) option is Equip KILO with fuel for the return + a bit of margin, dock it to MIKE after payload delivery (3xTANGO + 3T fuel) at an Ap matching Tylo's orbit. Compute (??)/Devine a grav assist to lift Pe to Laythe orbit. Correct the resulting orvit with MIKE remaining fuel, then enter in Laythe high E orbit. Aerobrake gently over many passes. Done. Less risky : beef up KILO with more fuel. That might require in beefing up MIKE's fuel too... so... not that great. An other potential issue I see with the Mothership is that we'll have FUEL+LIMA+KILO docked inline with Jr ports, that might create issues from Wienerli oscillations during the ejection burn (it was a major problem during my caveman Jool mission, I could not burn higher than 0.2-0.3 TWR) To answer @ManEatingApe questions : I can't move the 3 ports because they are the ports for the 2.5tank that get the thing into orbit. I used good'ol paint to annotate.

I have been working on the Mothership a bit, and how to place the landers & stuff in a practical way. An other thing I have been thinking about is a contingency plan if things go pear shaped, for example from a surprise encounter with a moon or something else costing quite a bit of DV. What I propose is the following : - make sure that the TANGO design can dock in a way such that it could be used as a backup engine with a 3T tank from a FOXTROT tender. This means that one could reconfigure the mothership to have said backup tank as the core and one of the TANGO lander as engine. - Take an extra 3T of fuel as backup, with a few radial Jr ports (2 or 4) so that we can dock things to it. Here is a the core with dummy landers :

After a few more headaches, I got it working. Moral of the story is that being accurate as caveman is all about being tricky I added it in the repo along with the kerbol system definitions required by it. It's a bit of a mess and not really user friendly. Would require some refactoring and stuff as this is pretty much a pile of tricks glued together. Other requried packages like PyKep, numpy & al would have to be installed to make use of it. As a bonus, here is the first result.

No. Having deltas is the sign that either (or combo of) : 1) There is an error on the times used to compute 2) There is an error on the eccentricity 3) There is an error on the SMA 4) There is an error on the central body standard gravitational parameter Previously I forgot to correct Ap/Pe for kerbol radius, so I got a ~1% error on numbers. At this point I can exclude errors on SMA & e. I also found that the central body grav parameter was a bit off. I computed it again from kerbin speed, and then did further corrections. Speeds at t0 and t1 have now deltas of less than 1 m/s, which is remarquable. I also got the Lamber solver working for a craft-Jool encounter, but there is an issue with times and/or ArgPe because the calculated burn is about 10 m/s off (on a 135 m/s burn). Which is enough for a miss. This is likely linked to some issues I have when the Pe is very close to the ejection burn. The error looks to be of about 3° on ArgPe.

The Deltas are the difference between the predicted value from propagating the orbit, and the actual ingame values. rL is radius at launch. I have since also checked eccentricity, which is also okay, and ArgPe accuracy seems okay at ~0.1° I have a sloppy jool ejections that I will try to salvage with the updated version using Lambert. All will be put in the repo once it's cleaned up a tad.

The NavTool is moving ahead nicely after a few headaches. The error on altitude and speeds are now under control. Under 0.01% which should be good enough. The test was done with a random burn at a random time. The trajectory is build from one data point, two other are used as controls. Once the Keplerian elements are known, I convert them to carthesian ones, and then propagate the orbit to t0 and t1 (times of control points) and compute the altitude and speed, then compare to measures. I have yet to verify the accuracy of the argument of Pe, but it can only be done with a full test with a correction burn and an encounter. I have a porkchop/Lambert solver for the Kerbin-Duna transfer, adaptating it should be rather simple.

I think I have mostly solved the problem of getting the orbital parameters of the transfer orbit from caveman infos. I now have to go from paper to code. I found a way to get the argument of periapsis without rulers. I will do a test with a real transfer as soon as times permits. Thereare a few things I have to sort put w.r.t to the inclination correction burn, but not a showstopper. Getting the side boosters strapped on the mothership is... an interesting exercise...

Graphics mods are fine for me. I am working on the mothership with on pad assembly. 2.5m center core with a poodle on the bottom, a 2.5m drop tank on top and 6 side boosters. If everything works, that should give us a poodle with 12tons of fuel and 10 docking ports. (6 on the sides, 4 in the front, one of which is central.) If we add 3x3 tons of fuel with the tenders, that would be 21tons, likely enough if everything else can stay under 10t. Assuming 10t of payload, that would mean about 3100 DV. I'm also starting on the jool ejection/correction script.

I think the mission plan is sound, and I think the changes are sensible. My only worry is the accuracy/planing of the ejection from Laythe to return kerbin. This will require maths.

Speaking of which : the best part from the MH DLC for caveman is the bobcat engine. It frees quite a few parts from the sparks and nose cones. Like 6 to 8 XD but yeah, tangent appart, launch convenience is super important. Getting the poodle up is going to require on pad assembly though.

I think that @IncongruousGoat has already done a nifty Tylo lander with a mass ~2 tons. There was also a staged spaceplane proposal for Laythe. For option B it will require the orbital parameters of Jool. This is easy to get (measuring tools, epoch 0) so long as we work with coplanar trajectories (no need of knowing An/Dn). Alternatively I have already the parameters in a python dict from previous works with pykep. I have to get a look at the Lambert solver. If I am Correct, this is easier than it looks, since we get speed, altitude (kerbol) and time in game without upgrades. As long as the trajectories are coplanar I'm quite sure this is enough.

I think we can avoid the extra DV by either : Do an encounter over multiple with a Pe correction at Ap to catch up Jool after a number of orbits. (This can be very accurate if done down to the second). Or go the extra mile. Launch as best as possible, correct inclination at mid transfer. Then solve the craft orbit, Jool's orbit and the Lambert problem for the encounter and calculate the correction burn. Correct. Encounter. option B is harder but would also be rather kickass IMO. I have an ESA package reconfigured for KSP (I use it for multiple grav assists planning, but it can surely do simple Lambert just fine). Just need to whip up some code to do it I suppose. If interest is there I could try to do it when times permits and do some tests with probes. But not before two weeks.

I would just like to point out a few things : 1) Tylo parking orbit. While it's great for a regular jool5, rendez-vous are tricky like @ManEatingApe said. Even more so in caveman with the lack of approach indicators. I worry a bit about doing multiple warps and correction burns with the guy on the ladder. That might prove costly for the RCS fuel. 2) a single kerbal because two is going to be herding cats. 3) ideally the capture should be done as a reverse assist with Tylo. Though without patched comics it's going to be "interesting". I won't be able to do much testing for the coming two weeks but I'll follow closely.

Primitive tech means no facility upgrades, so only T5 and lower. No patched comics nor manoeuvre nodes either. @IncongruousGoat nice testing. On my side I tried tricks like using landing legs (does not work), pistons and hinges to pin the kerbal still before warping, but it does not help in any way.

For the rules I think no DLC is a good idea since not everyone has them. github is also a nice idea and the rules generally suit me. I would advise againt grindy stuff, this is not the goal here. One thing that we might want to consider (if enough are interested) is doing some streaming for stuff like transfer/capture and then the different landing. It would be nice, even if it'll just be watchin and chating As for the mothership, I tend to guestimate the landers mass & stuff, eyeball the hardware and then iterate.

I have made bit of work on a return vehicle based on the Laythe lander from IncongruousGoat. 1) I fixed the ascent stability and found a nice way to boost overall DV from the launch. Simply put, my craft was too light and made the rockets to top over. Which is a classical problem. What I did is put an FLT400 on top with the nose cone, which is then ditched in space. 2) The lower stage plus top tank is nearly enough (or likely enough with a really good turn) to get in orbit. In short : the craft gets in LKO with a fully filled FLT400, which is neat. 3) The capsule does just fine on rentry, tested with AP = 1000km, kerbal was fine. I assume we'll do a personal chute landing soviet style to land => we'll have to level up the dude. Also, I had a look for the mother ship. If we can keep the overall landers + return stage masses at 9tons, a transfer stage like this would work : The poodle + tank is for sure possible with on pad assembly. maybe even a bigger tank. The four drop tanks can each be done with a regular lauch, which is not too crazy. The two FLT800 are the payload mass (9tons). It has TWR of ~1 which makes ejection not too painfull. 2400 DV can be pushed a tad by droping the side tanks first. That's enough for ejection and an eliptical jool capture. What do you guys thing about something like this ? If anyone has a idea to minimize kerbal drif with warp, it would be a godsend !

Indeed. Experience with on pad assembly, for example would be really neat. (I can do some half backed stuff, but it was not very good TBH XD) Also, we will need a way to navigate the jool system in our terms, i.e. avoiding crapy encounters.

Damn that's clever. I tried to use the fairings, either as a structural tube replacement with the pop-can design, or as an envellope around it, but I did not think about the interstage nodes + offsets, so it failed (can't "open" a fairing with a hinge or piston). The radiators will be a nightmare on ascent though. I will try doing a pop-can design out of it to trim down drag. Also, it will need a Jr port somewhere to glue it with the other parts. It would also be nice if it can deal with the return Kerbin re-entry.

That is a neat design. 2Tons is more than okay and using bagette is a great choice since they have the best wet over dry ratio. I tried tons of laythe/return vehicle to little avail. It seems that there are two issues : 1) For some reason the node with the hinge attached to is considered "nacked", creating tons of drag and rocket flipping issues. 2) KSP sees airflow in the "closed" structural element, making Jeb lose the ladder and then burn. My guess is that since it closes with the hinge, in ksp logic it's still open on one end. I have a few tricks up on my sleve to test out. For example, if the kerbal is on a ladder attached to a radiator, does the radiator cool the kerbal ?