OPERATION: Jools Verne

[Randazzo]

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So I'm new here, having just purchased KSP shortly after it went into 0.90. In that time I've put (shamefully) over 100 hours into the game. Tonight I just completed my second visit to Jool but with a far more complicated tour than my initial exploration contract visit which required only a Jool orbit. This mission took place over 2 days (of my time) but took almost 5 years Kerbal time mostly waiting for the right phase angle and transit time. I was tasked with exploring Bop, Tylo, and Pol as well as with retrieving science data from space around Laythe. Atypically, I had the presence of mind to take some screenshots, though I did unfortunately neglect to record most of the probe deliveries out of being too involved with them. Releasing them on flyby and switching over to control the orbital burn and then switching back and adjusting the main vessels escape course back into a reasonable escape vector was a little tasking for me, particularly around Tylo.

The main craft for the mission is the KSS Kerbinia, which has been my "Flagship" as it were for the majority of my interplanetary missions. Unencumbered she boasts just shy of 9,500 Delta V, carries 300 units of monopropellant and a two-kerbal crew. The Kerbinia is designed to be expandable (though not recoverable to Kerbin's surface) and has 4 fore-facing Jr docking ports, 1 belly-mounted standard port, and 1 aft-facing Sr port for accepting fuel and/or engine extension pods. The Jr ports are for accepting small landers or probes, and the standard port can accept most anything (I typically use it to attach small science pods) provided it's mass isn't so high as to cause pitch during burns that cannot be countered by SAS and RCS.

To complete this particular mission, I added an engine and fuel pod with an additional 4 LV-N engines and a large rockomax fuel tank which ultimately brought my total Delta V to roughly 12,000. I know that's quite a lot, but having visited Jool once prior I was aware it is a moon minefield and wanted room for a lot of accidental slingshots. I did use Mechjeb for the porkchop selections and slowing down around Tylo (as well as attempting to land on Tylo), but all other burns and transfers were done manually. Four probes were also attached via the Jr Docking ports for release around each target moon. All of these five extensions were sent up on a single rocket using a quad-adapter at the top to carry the four probes. This actually resulted in shearing off some of the probes solar panels when decoupling since I didn't offset them properly. After docking everything to the Kerbinia, I was ready to set out.

After achieving an intercept course via Mechjeb, I adjusted my course into Jools SOI into a gravity capture around Laythe. This seemed to be a bright idea to me, capture at the innermost moon and work my way out. However, I neglected to consider my ludicrous speed (which I should have recorded, I do believe it was in excess of 8,000 m/s.). Fortunately as many of you know, Laythe has an atmosphere, so I pushed my periapsis down in hopes of an Aerocapture. Those hopes were dashed, and although I did bleed off a significant amount of energy, I was ultimately flung into a Jool encounter. Fortunately it was a fairly reasonable course and I was able to execute a second aerobrake maneuver around Jool itself which resulted in orbit. I plotted a course back into a Laythe encounter from there, and returned to deploy my probe. While it technically was not necessary to complete the contract objective, I brought the darned thing and I intended to deploy it. On my second encounter with Laythe at a far more reasonable speed, I undocked the probe and switched control. A short burn later and the probe was on it's way to the atmosphere for entry. Once the desired course was achieved, I took a gravioli scan from space to complete the objective and with that it was back to the Kerbinia to plot my escape trajectory. I had intended to try and escape directly to Tylo (and thought I had lined up my approach so very carefully). In what really was a brilliant stroke of luck, I indeed managed an encounter with Tylo with minor adjustments to my escape vector. My Laythe probe now had a minute or so before impact, so it was another quick switch to deploy chutes and perform the available experiments.

In control of the Kerbinia once again, I initiated time-warp to start my Tylo maneuver. It was here that the mission hit it's second problematic snag. Though I used maneuver nodes to plot the course, the rogue that is Vall snatched me into it's gravity at 100x time warp and in the moment it took me to return to real-time, my course was too far gone to correct without a tremendous burn. Not only did this incident take me off course from Tylo, I was passing behind Vall and ended up on an extremely elliptical Jool orbit (about 30 days for a complete orbit) and gained energy in the process. No maneuvers I could plan within an acceptable amount of Delta V had any desired effect, so there was little I could do but allow myself to be tossed back into Jool orbit and perform yet another Aerobraking maneuver. I transferred all remaining fuel from my extension tank into the main tank and decoupled it relieving the Kerbinia of it's bulk, and burned my periapsis into the atmosphere of Jool. However, on my journey toward the periapsis, Vall again blindsided me and though the overall effect was less drastic this time, tossed my periapsis out to nearly 1,000 Km. After some creative use of English, I corrected my periapsis into the atmosphere again with a significant burn and this time successfully achieved a much lower orbit then plotted a course back to Tylo which was no doubt inefficient, but kept me well clear of Vall.

Actually reaching Tylo this time, I could not (at least in the time frame I had to make corrections and deploy a probe and then maneuver the probe) create an escape trajectory to Bop or Pol nor could I achieve an orbit for less than 3500 Delta V. I attempted Mechjeb which provided a similar solution, and so resigned myself to simply deploying the Tylo probe while the Kerbinia went back into Jool orbit. The probe itself had 4,100 Delta V which was sufficient only to attain orbit, and then smash itself to bits in a Lithobraking maneuver. I had not done my due diligence on Tylo (My standard probe design has 4,100 by default and slightly less if I tack some parachutes on it.) and did not realize what a feat landing on it's surface was. Landing and Transmitting data would have to be done on another mission.

After making some adjustments to my resulting Jool orbit, I realized I would not be able to attain a Bop or Pol capture without changing my inclination significantly. This took another fairly long burn and left me below my desired safety margin to about 4,100 Delta V. Though it was theoretically enough to complete all objectives and return home, the Kerbinias inability to simply plot a degrading orbit at Kerbin and re-enter requires having enough fuel to match orbit with it's docking station. Even failing that I can send a drone fuel pod as long as I attain a decent orbit, but I'm super paranoid about running out of fuel due to early experiences. Fortunately the rest of the mission went off without a hitch and both Bop and Pol required much less to orbit around than all of my previous encounters in Jool's SOI. I successfully deployed probes to both moons and completed both exploration contracts. Ultimately the mission was largely a success, failing only to land on Tylo and get science data from it's surface.

With all of this done I again used Mechjeb to plot a transfer back to Kerbin (after getting back into a very high Jool orbit) and proceeded to time-warp through the year long journey. Ultimately the Kerbinia returned to it's station with ~900 Delta V to spare. I sent a recovery pod over from my nearby science station to recover the crew and (again cheated and used mechjeb, I was worn out!) re-entered Kerbins atmosphere. Since I was cheating anyway, I had mechjeb land them on the Launch Pad for extra awesome. Both crew members earned 28xp and advanced to level 4, and my most complicated and harrowing mission to date concluded as (mostly) a success.

Edited January 26, 2015 by Randazzo
put the pictures at the top