FourJade - Not Quite a Jool-5 (Contains Images)

[Concentric]

Not feeling up to Tylo? Do the others, instead.

At time of writing, it is 33 days until the Jool transfer window. Jeb has just returned from a testing mission, examining the capabilities of the FourJade ion lander planned to land on Pol and Bop, as well as those of the landerprobes. Soon, the launches shall begin, and the FourJade ship will be assembled in Kerbin orbit. I shall begin this report with an explanation of the FourJade mission.

Our examination of the data from a probe previously sent to Laythe and the Jool system has revealed the startling strength of gravity of Tylo - and more importantly, its lack of atmosphere. Our engineers do not feel sufficiently prepared to construct a safe Tylo lander at this time, and while an indepth, multiprobe examination mission could be sent out, Commander Jebadiah Kerman is of the opinion that it would be a wasted opportunity not to send a mission to land on the other four moons of Jool. As such, we prepare. A transfer ship and lifter have been constructed, prepared to carry three veteran kerbonauts to Jool along with the landers. A Mun lander has been given additional thrust and fuel, rendering it more than capable of hovering on Kerbin: this will land on Vall. So, Laythe, Pol and Bop remained.

Previous testing and improvement connected with the RedKing mission has created a lander that can descend from Kerbin orbit, land on parachutes alone, then ascend back to Kerbin orbit, and from there, even transfer to the Mun. This lander has been slightly tweaked, and is now the FourJade Laythe lander. Its capsule also serves as an ion lander - and this is what Jebadiah has been testing over the last few weeks.

The first liftoff showed a small problem: probe cores had been left off the two lander probes that were also to be tested. Jeb returned, shouted at the engineers for making such an idiotic oversight, and personally supervised the reconstruction. Then, he launched again.

The lander probes had limited power generation and charge storage capabilities - not a great combination with their ion engines, to be sure. As such, coordinating the transfers from Kerbin orbit to Mun and Minmus was difficult and tedious: the cause of sleepless nights for several in mission control. Several times, burns were within minutes of each other, and windows were missed due to an overestimation of how long the probes could fire their engines at full thrust.

The Mun probe in particular had to make some drastic adjustments to its orbit in the hopes of getting into the Mun's sphere of influence. It eventually succeeded, but its inability to run at full thrust for any reasonable length of time - combined with its already low thrust-to-weight ratio - caused a catastrophic failure in landing.

The Minmus probe had its encounter only slightly before Jeb was to encounter Minmus himself, so it got into orbit before him, and landed after.

Minmus' gravity was sufficiently low that the probe could land without serious difficulty, keeping its power usage below its generation capability. It later lifted off and came down hard in the Northern oceans of Kerbin.

Jebadiah himself had a rather easy time with Minmus. He had previously landed on Minmus using an ion lander of lesser specifications, after all: this one had an additional engine, over twice the charge, a little more power generation capability and far, far more xenon. The landing was more of a refresher course, as well as making absolutely certain that FourJade's ion lander would be capable of landing on Pol and Bop.

The return was a two-pass affair: first to bring the apoapsis below one million metres, and second to parachute into the ocean.

There was, however, a slight visual glitch with our monitoring. Somehow, it appeared that the ocean - no, the very planet - had disappeared, leaving only a blue light at the core. We warned Jebadiah that we couldn't reliably monitor this final stage of his landing, but he shrugged it off. "Done this more times than you've had hot dinners, Control: anything that could go wrong here, I'm more than qualified to take care of it." He was correct, as it turned out. Though our monitoring was still unable to detect the planet, Jeb was floating in the ocean, perfectly safe. He directed the recovery team to him with his lander's radio and radar gear, and made it home.

Soon, the components of FourJade will launch to assemble in orbit. Bill, Bob, and Jebadiah are engaged in rigorous training as I write this, preparing for their biggest, longest, most complex mission to date. Little more than a month remains before FourJade is truly underway.

[Concentric]

Docking, am I right?

With roughly ten percent of the outward journey left until the transfer window, Commander Jebadiah has argued that it is probably best to get into orbit and assemble the FourJade mission ship at this time. This has been the work of the last few days. First, the Laythe and Vall components were sent up uncrewed into parking orbits at 120km ASL. Then, the transfer ship followed, and the docking began.

The Laythe Lander's launch was ordinary, dropping SRBs, LFBs, then drop tanks. Circularising very nearly wiped out the remaining fuel of the lifter stage. It would have perhaps been wiser to put it in a lower orbit, upon later reflection.

The Vall component, too, ascended routinely, as in lifter testing. It had far more fuel left in the lifter stage for rendezvous purposes.

After the uncrewed components were sent up, it was time to launch the main ship. This was fitted with a launch escape system, so it was pronounced safe to send the crew up within. Jeb, Bill and Bob - our most decorated kerbonauts - climbed into the capsule and the launch began.

Everything seemed to be going swimmingly: the LFBs dropped as planned, the thrust-to-weight ratio remained above one... then disaster struck as the SRBs were released:

One of the SRBs failed to clear the engines, and was destroyed while in a critical position, taking three of the five engine clusters with it. Immediately, Jebadiah hammered the Abort Launch button, taking the capsule free of the wildly spinning rocket.

The launch escape system and parachutes operated precisely as in testing, safely depositing the capsule and crew within sight of the launch pad. After some brainstorming and hasty modifications, the launch was ready to go again. Jebadiah was seen dragging Bob to the capsule for the second launch, while Bill, it is presumed, was reassuring him. "Even if the rocket does go wrong again, the escape system's been so thoroughly tested... I'd put my kids in it, Bob. It's perfectly safe."

(A quick note: Bill Kerman has no children, but this is apparently a very reassuring phrase. -Ed.)

A slight rearrangement of engine clusters, and the addition of separatrons to the SRBs ensured that should they be destroyed after being jettisoned, they wouldn't damage the clusters. The launch, therefore, worked perfectly well and put the ship into a slightly lower orbit than the uncrewed components. Next, Control brought the Vall component into an intersecting orbit and docked it to the nose of the ship.

The docking of the Laythe component was more difficult: a critical burn was missed by more than an orbit, and remaining fuel and monopropellant on the lifter ran out far too soon, putting the component in a slightly eccentric orbit. As it is said, if the component would not come to the ship, the ship would have to go to the component. And so, using the remaining fuel in the final lifter stage, it did so. Once orbits were matched and the distance was less than a kilometre, it was time to remove the final lifter stage, as it would be in the way of the docking port. So it deorbited itself, and docking continued.

It is a matter of days before the Jool window. With the FourJade ship completed and crewed in Kerbin orbit, the final stages of planning and calculation for the journey begin now.

[Concentric]

30 days is far too long to expect Jebadiah Kerman to wait in LKO.

Commander Jebadiah Kerman is, at times, an impatient man. It therefore should come as no surprise to anyone that, once the FourJade mission ship was in a 100km circular orbit, he immediately began to plan as early a Jool transfer as he could arrange. Initially, not knowing how long it would take the nuclear engines to burn it, he planned to burn the escape almost immediately - before completing an orbit at 100km circular.

Jeb's first plan - flying in the face of the flight plan

The engines were fired up to estimate the burn time a little over three minutes before the node - but the burn would be almost 15 minutes long. Jeb managed to keep the throttle on full, despite Bill's complaints about "following the flight plan" and "recalculating to take this into account". He burnt fully half of the 1711m/s maneuver, then cut the throttle and did the recalculations himself.

The Laythe lander's nuclear engine also fires: six nuclear engines isn't much thrust for this thing, really.

Jeb's recalculation

Due to fuel cross-feed, the engines burned fuel from the Vall and Laythe landers rather than from the transfer stage. As such, on the orbit between maneuvers, the crew had to perform several fuel transfers. Fuel cross-feed remained active, and Bob made note to disable it after the second fuel transfer after the escape burn - at which point, the Laythe lander's nuclear engine would be disabled.

The second seven minute burn began just before the FourJade ship passed the solar terminator. Control kept a close eye on the ship's periapse, ensuring that it didn't pass below 90km ASL to be absolutely certain that it would not fall into Kerbin's atmosphere. It was determined that had the initial orbit been too much lower, such an incident may have come to pass. The calculations, of course, had not factored in potential atmospheric effects - so this could have changed the trajectory massively.

On the way out, more fuel transfers were performed to replenish the supplies of the Laythe and Vall landers, then fuel cross-feed and the Laythe lander's nuclear engine were disabled. Additionally, the mid-course correction maneuver was adjusted so that a Laythe encounter was predicted - the plan being to aerobrake directly into Laythe orbit. Fine tuning could come later.

Mid-course correction - no radial burns

And now, Jeb, Bill and Bob race outward on a Kerbin escape, with almost 210 days until their next burn. It has been revealed that Bill brought along a pack of cards and considerable innovation in microgravity card games. Perhaps this will prevent Jebadiah's impatience from messing up the flight plan again. Or perhaps one of our kerbonauts will own all the others' possessions by the time they return. We have no way of knowing these things at this time.

[Concentric]

It's astounding. Time is fleeting.

Madness... takes its toll

Finally, after over a year and a half, the FourJade mission ship has arrived at its destination. Just as was predicted at the time of the mid-journey adjustment burn, the ship swept past Jool before heading towards a Laythe encounter. Bob calculated that with only a small retrograde burn at Jool periapse, the ship could lower its Laythe periapse sufficiently in order to aerobrake into orbit directly at Laythe. With the Laythe lander making up such a large proportion of the bulk of the ship (now that the transfer stage's tanks were emptier), this had been determined to be the best staging area for this mission.

Simulations determined that a Laythe periapse of 22km would serve to put the ship into an orbit that could then be further refined.

The approach. Jool, Tylo, Laythe and Vall are all visible in this image

The burn, reducing the Laythe periapse

Somehow, Bill's expertise and Jeb's luck cancelled each other out on the card games on the way out here - Bob had to rely on his so-called "Mission Critical work" things somehow preventing him from playing all the time to avoid losing too much to either of them, the miserable spoilsport sod. Although, that did mean that he was the one behind the simulations and calculations that lead to multiple successful aerobrake passes. Funny how that works. Perhaps, since he loves piloting this transfer stage part, he can continue to do so for the rest of the mission! That'll cheer him up, I'm sure.

Mission Critical work - the only reason this aerobrake worked at all.

... and this one.

Reports were taken down, and Bill made sure to change the crew-report storage while making his EVA high above Laythe. Once the Laythe apoapsis had been reduced below 200km, Bob performed a couple of small burns, raising the periapse and lowering the apoapse until FourJade was in a nice, circular 100km orbit:

Additionally, some kind of interplanetary (or possibly Joolian) space-gremlin has been playing silly buggers with the docking clamps! Fuel Crossfeed keeps being turned on unnecessarily! (Wait, wasn't it supposed to be on? -Bill | NO! I made specific note, you illiterate imbecile! -Bob | Tensions can run high after being crammed into a pod for about two years straight with the same people. -Cmdr. Jebadiah Kerman, MPsych) (The previous is an excerpt from the second crew report performed in Laythe orbit. Bob had to get some space immediately afterwards, so volunteered to take the EVA report in near-Laythe orbit.)

Fuel transfer? What, again?

The Jool system is a marvelously cinematic place. A great many images were taken - and this before visiting the other moons!

Ever notice how, in the moments before sunrise over Laythe/after sunset over Laythe, you can see Kerbol as a shining dot through Laythe's oceans?

Because I did, taking some of these.

Edited July 2, 2014 by Concentric

[Concentric]

Ah, sun, sea, sand and green gas giants.

(You can find the initial, failed attempt at this landing here. It has a pretty explosion in it. The following depicts the second attempt, which was rather more successful.)

Vall and Jool over Laythe.

On this day, the first of FourJade's landings has been successfully performed! Commander Jebadiah Kerman, he of the falsified psychology degree, (We checked. Astrodynamics yes, psychology no.) has touched down upon the beaches of Laythe, planted a flag, and claimed it in the name of all Kerbal-kind! Indigenous creatures, you should have made your flag clearer, because at the very least, this beach is now our property. (On the other hand, our Theoretical Xenobiologists tell me that if Laythe does have intelligent life, it is likely ocean-dwelling, and unlikely to care about the land, so perhaps it doesn't matter.)

First, Jeb transferred to the Laythe lander and undocked it from the transfer stage. Then, a descent trajectory was planned and the corresponding deorbit burn calculated. Then, it was time to burn.

About halfway into the roughly five and a half minute burn, Vall could be seen rising over Laythe

Jeb took reports in Laythe's upper atmosphere, before atmospheric effects built to the point that he might have difficulty holding onto the ladder.

Shortly after atmospheric effects ceased to be visible, the lander began to pass over the island that had been selected as a landing site. Thus, drogue 'chutes were deployed. The other parachutes were also deployed as the lander decelerated. At roughly 3000m ASL, Jeb took more reports, as he was clearly no longer in the upper atmosphere of Laythe.

The lander came down over a beach, a little over a kilometre above sea level. The thicker atmosphere and length of time slowed the lander below 10m/s before the landing legs touched the ground, depositing the lander safely on the reasonably flat surface. Jeb repacked the capsule's parachutes, extended the solar panels and lowered the ladders.

Then it was time to repair the broken landing legs. The I-beam structural support gear held up perfectly, keeping the engines clear of the ground just as it had in testing, but the LT-2 landing legs themselves had suffered damage.

Finally, Commander Jebadiah Kerman planted the flag, and got a nice picture with it, the lander, and Vall. A wonderful success.

[Concentric]

You can tell by the way I make my pun: Vall's like hall, and unlike pal.

This was a day of many transfers. First, Bill transferred to the Vall lander can and undocked from the main FourJade ship. Then, using the three ion probes docked to the Vall lander, he transferred to Vall orbit. Additionally, Bob began the FourJade ship's journey to get a Tylo flyby, but the tale of Bob will not appear in this entry. Jeb wasn't entirely idle, either - he went for a short night swim between two long runs (with some stopping).

That's a long run just to pick up a little ocean water... Perhaps I'll bring an amphibious rover, or a space-seaplane the next time I come to Laythe...

So, on to the main subject of this entry: Bill's excellent adventure. First, an escape burn was planned that just barely escaped Laythe's SOI. If the escape was directly prograde, the resulting Jool orbit would take Bill out past Tylo without a hope of a Vall encounter, so its position had to be somewhat fiddled with.

First, the monopropellant in the small tanks that were blocking the ion engines had to be used up, so they could be staged away. Then, it was time for a series of burns on the trio of ion engines. Low power generation (a total of 11 RTGs and 3 OX-STAT panels) meant that they couldn't thrust at full power for very long, though they could keep up one-third throttle indefinitely. As such, it took three burns to escape.

The trajectory at Vall was coming in retrograde, so Bill set up a maneuver in Jool orbit to move it through the moon to the other side. The above map image is about two thirds of the way through that burn, which was again slow due to power constraints. Jebadiah reached the ocean while Bill was waiting for his encounter.

Bill took reports in Vall orbit, even as the engines continued to fire. The thrust on three ion engines just isn't enough to shake loose the powerful grip of a Kerbonaut. Of course, he'd have to be a fool to try it with more potent engines... and the FourJade mission's selection process suffered no fools.

Once orbit was obtained, it was time to adjust inclination and lower the apoapse. It was around this time that Jeb got back to the Laythe lander, too.

After a few passes and some more report-taking, the Vall lander and its attached ion probes were in a nice, equatorial, circular orbit at 50km ASL. Then, it was time to detach the probes.

First, some of the xenon in the probes was reshuffled, as they were to serve slightly different purposes. From the probe that was to remain in Vall orbit and dock to the ascent stage after the landing, one of its radial xenon tanks was emptied into the axial tank core of each of the other probes, and the remaining one emptied into its own axial tank. Then, they were detached and renamed.

A deorbit maneuver was set up to take the lander into one of the lower, flatter-looking blue sections of Vall. Our engineers were reasonably confident that the lander would be able to handle this perfectly, and in the case that things went slightly wrong, the ascent stage had just as much thrust, and could be activated without decoupling from the descent stage if required.

The Vall landing was shortly after sunrise, and as Laythe was setting behind Jool. Vall so far appears as though it might be tidally locked with Jool - while Bill waited for the sun to get into a more favourable position for a photo-opportunity, Jool appeared to be constantly looming on the horizon (or possibly rising extremely slowly).

As for the landing itself, the descent trajectory could probably have been a touch more efficient, as the descent stage was used in its entirety. However, only the tiniest of bursts of the ascent stage's fuel was needed to perform a safe touchdown. Though no calculations have been run on it, here at Mission Control, I have confidence that the ascent stage can attain an orbit - and that should be enough to dock with the ion probe waiting for it with an engine and 619 xenon.

This image is actually rather reminiscent of the archive's first screenshot: a landing on Minmus with Kerbin in the background, flag-kerbonaut-lander from left to right and the sun somewhere behind the camera. It's even also on a low, flat(ish), blue-coloured area.

And that's Vall, folks.

[Concentric]

Or, Of Bob and the Meaning of Near

First things first: Bob getting the reports not already planned to be grabbed by another - specifically, the Space Near Jool and both sets of Tylo space reports. Also, the Bop and Pol probes went for their landings. Bop's got that obnoxiously high no-warp altitude that makes landing there slow and irritating, but the experience of landing something there may prove valuable.

The only remaining Kerbonaut in the main capsule, Bob knew that he would not get the chance to perform any landings when roles were assigned. However, he had other jobs to do. It was decided that the best way to get the ship close to Jool would be to perform a gravity assist downwards at Tylo, and then later perform one upwards to get out of such a close, atmosphere-scraping orbit. These would give Bob the opportunity to visit Tylo and take reports there - something unique that Bill and Jeb hadn't done.

His Laythe escape burn was not all that long after Bill's on his journey to Vall: it had been noted that Bill could have had a Tylo encounter if he stopped his burn to Vall partway. Unfortunately, he did not immediately get such an encounter, and so another burn maneuver had to be planned in Jool orbit.

After the burn, Bob thought that his projected Jool periapse was low... but perhaps not low enough. With no idea how close he needed to get for the research department to consider it "near", so he planned a burn at Tylo periapse to make use of the Oberth effect and bring his orbit closer to Jool's atmosphere.

He took reports high over Tylo, made his burn, and noted that the flyby had not passed close enough to Tylo to be called "near". Then, he escaped Tylo and began to approach Jool more closely.

As he reached his periapse, the spedometer on the navball began to malfunction. Somehow, despite Jool supposedly being a gas giant (and thus not having a surface) the navball had automatically changed to measuring speed in surface mode. Not sure why that happened. According to tracking station data, Jool's atmosphere wouldn't start for a little way yet, but Bob's flight took him closer than was expected.

After the flyby near Jool, a series of maneuvers was planned to get a closer Tylo flyby.

Sure, a Vall intercept after the Tylo flyby, why not?

Looks almost like an eye of some sort...

A burn was planned at Tylo periapse to bring the Jool one up somewhat.

The earliest point at which Bob attempted to make reports for space near Tylo. The maneuver is the above-mentioned burn.

And another burn, to move the orbit a little.

---

Of course, Bob's orbital movements were not the only goings on. In the Vall entry, we saw a pair of probes marked for Bop and Pol landings. While Bob was doing all this, the probes were also moving.

First, they had to leave Vall's orbit. Then, the Bop probe began to match Bop's inclination.

Got distracted while waiting for the burn to complete and overshot it somewhat.

The Pol probe had less of an inclination burn, but needed a longer injection.

Arrivals occurred after Bob had completed his second Tylo flyby, and it was straightforward to achieve orbit.

While the Bop probe was first to arrive and first to get orbit, the Pol probe performed its landing first. It was a straight, vertical landing from 25km orbit, which on Pol is not too difficult with a light landing probe. It's an inefficient way, but it was functional, and it's not as though an ion engine with ~800 remaining xenon on a very light probe adds up to a delta-v deficit.

I heard Pol had spiky bits... was I wrong, or just in a different place?

Then, Bop. Also, the most annoying thing.

That there made Bop much more tiresome to land on than Pol.

Particularly when landing so far below it.

[Concentric]

And with this, all that remains is to gather up and go home. Wow.

The Pol/Bop lander of the FourJade mission is a reasonably powerful ion lander with three ion engines and twelve radial xenon tanks that also serves as the capsule for the Laythe lander. As such, the last two landings in this mission are Jeb's to perform, as he's already in the lander for it. First, of course, getting off Laythe.

After fixing the fuel imbalance in the droptanks, it was time for liftoff. Due to the way in which I fixed said imbalance, the droptanks were dropped in threes rather than all at once. The Laythe lander drops those tanks and its outermost engines quickly - they are rather small and providing fuel to six aerospikes simultaneously at the start of the launch on an atmospheric planet, after all.

A brief glimpse of the sun as it rises over Laythe and sets under Jool

Once out of the atmosphere, the engines are switched to conserve fuel: the nuclear engine will provide plenty of thrust to circularise the orbit, and the outer tanks will be dropped once the total liquid fuel reaches 180 - just enough to fit in the central tank. These outer tanks are linked to the central one, sharing fuel equally, so it is necessary to use the resource window to know when to drop them.

They are dropped before the periapse leaves the atmosphere, though after it appears. Due to the lower difference in inclination, and the fact that it is easier to change inclination at a greater altitude in the gravity well, Commander Jebadiah Kerman will first head to Pol.

With the right escape, it is possible to get a Tylo gravity assist after almost a full orbit, and then make an adjustment at the descending node to get close to Pol after another few orbits.

By dragging the maneuver node through the Tylo escape, you can force an additional orbit projection of your current trajectory.

I think I've said this before, but the Jool system really is very cinematic. Definitely a place every player should try to visit at least once.

With a small adjustment before Tylo, and one afterwards, Jeb calculated that he can get to Pol for slightly less delta-v. At this point, I hadn't quite thought about just how far 4800 xenon could get a landercan (or even that that was how much was on the lander). Also, the use of the LV-N's higher thrust to reduce burn times was also attractive, so fuel-saving was not entirely unimportant.

Ran into an unusual bug, not sure how it happened. Somehow, every maneuver node I placed after the Tylo assist had a delta-v over 3000m/s before I had even tried to plot a burn there. In fact, the one I placed there earlier also developed this, when I was reasonably certain it said 25m/s the previous time I had checked. So I remembered the rough location and plotted it again after the gravity assist. It was an orbit or two later, and the Pol periapse was not for 33 days. Bob had a Tylo encounter in this time, so I decided to use it to boost the main ship's periapse close to Vall, and also reduce inclination somewhat.

Then Jeb performed his burn for the encounter, putting his Pol periapse at around 50km. The ion lander can redock with the nuclear probe for further journeys, so getting a nice circular orbit at a memorable altitude will help with that.

Jeb neglected to take down reports on the way in, only realising it as he was landing. Also, due to the way that the Laythe lander was constructed, it was a decoupling, not an undocking, that was performed in Pol orbit.

The Pol landing probe was on the day side of Pol again, so Jeb decided to come down close to it. This site was chosen for a number of reasons: it was there, there would be sunlight for the solar panels, and a lack of landing lights made the ability to see the lander's shadow an extremely valuable tool. Additionally, Mission Control wanted a picture of him standing with the landing probe on an alien surface. This probably didn't factor into his decision in the slightest.

The landing ended up being straight down, and was extremely smooth and gentle. Three ion engines is more than enough thrust for such a small lander in Pol's gravity.

Near-Pol-space reports were taken in the final stages of Jeb's descent, then surface reports and a surface sample as he planted the flag. Then it was time to make the trek to the probe. The landing was not all that close to the probe's location, but Commander Jebadiah is fond of walking on alien land. He is unlikely to reveal the reason behind his decision to land where he did.

(What actually happened as to the landing: the decision to take a picture by the probe was made on impulse after Jeb got out. A spacewalk on Pol also seemed interesting, so I combined the two. I didn't intend to land right on top of the probe, anyway, but when I saw it was only 6km, I decided it was worth a visit.)

Somehow, our guidance software became confused as to the actual location of the probe, placing it far above the surface even though it had already landed. Checking in with the probe itself, Control managed to correct its position, and Jeb approached it.

Bigger than it first seems...

Then, when Jeb returned to the lander, a similar event occurred, fixed in the same way by switching focus to the lander's transponder and allowing Jeb to narrow down its location more accurately. Then, it was time to lift off again.

Here you can see the orbital nuclear drive probe as Jeb approaches.

Docking was not difficult, and it happened that once the lander had reached the rendezvous height, it was no longer "near" Pol. Jeb took down the last of the Pol reports immediately.

A series of maneuvers was planned, several days apart, to bring Jeb from Pol to Bop. Control also confirmed that Bob would have no encounters while Jeb was performing these. Bob didn't seem too interested in what Control had to say, instead requesting the transmission of sheet music for the ukelele he had constructed by taking apart leftover flags. He's certainly improved musically, but I suppose a long time alone without much to do but practise can do that.

The burns were rather short, using the LV-N. Jeb took reports immediately after entering Bop's SoI, just to be absolutely certain that he didn't forget them for this moon.

This time, it was an undocking, and not a decoupling that left the drive probe in a 100km orbit as the lander descended. Jeb descended rapidly towards Bop's surface, nowhere near the probe lander (which was just about on the night side).

After boosting the deceleration burn with some monopropellant, the very last bit of the landing was simple enough, though Jeb did suddenly realise he had no near-Bop-space reports and launched for a small suborbital hop to get them. The landing also ran into a strange error in the spedometer: it failed to automatically change to surface mode, even after the landing:

Surface reports, a sample and a flag, and the FourJade mission has only one task remaining: the return. Jeb is on Bop, Bob is in the main ship/return vehicle and Bill is still on Vall with three units of fuel missing from his ascent stage - will it have enough? Find out next time!

Edited July 10, 2014 by Concentric

[Concentric]

It's been a while since the return journey started, let me look at my notes...

Now that the mission is over and Jeb, Bill and Bob have returned, Gene's been bugging them to finish writing up their report. There's a new Space Program starting up that's taken over the centre and is looking to hire them - it even pays cash money! Unfortunately, all the research breakthroughs and milestones will be lost, but the experienced engineers should mean it won't be too difficult to discover them all over again. All that is needed is Bill, Bob and Jeb's piloting skill and experience - but they can't be hired until they've signed off the FourJade report!

So, where last we left off, Bob was in Jool orbit, Jeb was on Bop, and Bill was on Vall. We'll cover Jeb first.

Jeb lifted off and docked with his orbital drive rather simply. He then plotted his Bop escape and inclination adjustment.

The LV-N ran out of fuel part-way through the inclination burn, so Jeb undocked, turned around and fired up his central ion engine. The burn was slow, but steady. He next burned to reduce orbit and get an intersection with the adjusted orbit of the transfer ship.

Docking was a little fiddly, but it worked out fine.

Jeb transferred all the science over, but suddenly realised that he had deleted the Bob-surface crew report when moving monopropellant from the orbital drive. Too late to go back and get it...

---

Next, Bill.

Bill launched his ascent stage into Vall orbit and arranged an intercept with the ion transfer probe. Docking with it was straightforward, and it would provide the delta-v to dock with the transfer ship.

He boosted his escape burn slightly with remaining ascent stage fuel.

He docked to the rear of the ship and transferred over with the science.

The last of the fuel was drained into the tanks of the transfer ship. It was only a drop in the bucket, but Bill wanted to do it.

---

Finally, Bob.

With a couple of burns, Bob adjusted his orbit so that it was circular, equatorial and just above Vall - easy to find and rendezvous with. Then, with some waiting, Jeb docked, and after that Bill.

Immediately, there was a window for a Tylo flyby to escape that would need minimal adjustment outside of Jool's orbit to get a Kerbin intercept. The combined cost of these burns was 1437.5m/s

And after that burn, another maneuver was plotted at the orbit-height of Duna to lower the Kerbin periapse into the atmosphere.

Let's do the time warp again!

The Kerbonauts burned the final adjustment, bringing the periapse low enough to return to land by aerobraking.

With the periapse so low, it was decided that all that mattered was the safe return of the capsule and crew. Everything else was undocked and decoupled.

The landing was at 9.8m/s, too fast for the emergency ion engines, which provided a touch of lithobraking. The xenon supply went entirely unused on this mission. Jeb, Bill and Bob were recovered after their five-year mission to Jool, having completed all mission objectives and only lost a single report. The science return (despite no equipment being brought) was over 4.4 thousand. The brave, successful kerbonauts left together, and went to accept their First Contract.

And with that, the FourJade mission is complete, and I am unlikely to start up my 0.23.5 copy again. It was fun, and more complex than any other mission I've done. Jool and its moon-system is beautiful and full of photo-opportunities, and I'd recommend that every player visit at least once.