Long-term Laythe - Part 40

Pol Project Proceeds

OK...I did this stuff a few weeks ago, but haven't had time to write it up because of all the end-of-semester work...but now I have time!

At the end of last episode, Thompbles and Kurt had just completed their rover circumnavigation of Pol, and below we see Pol Fido 1 at the place where Thompbles first landed in the rover.

Thompbles: "Road trip over! I think we deserve a rest."
Kurt: "Indeed."
Thompbles: "Do you want to hop the Base over here, or should I handle it?"
Kurt: "I've already plotted the trajectory. Launching now."

Below, the un-crewed Pol Base Lander lifts off from the Base 3 location where Thompbles and Kurt last used it, and tilts over to pick up velocity toward the East. The six Rockomax 48-7S engines really are overkill in Pol's weak gravity, so one must be gentle with the throttle.

The suborbital hop would carry the Base Lander about one third of the way around Pol. Kurt kept the apoapsis to just over 11 kilometers. The whole hop would took about 18 minutes.

The three-part image below shows the Base leaving the Base 3 area, then turned around and crossing over Crossfield Crater, and then firing rockets as it approached it landing target.

When the Base Lander got within two kilometers of the Fido and had slowed to a near stop, I switched over to the rover and then the flag and then back to the Lander to make sure everything was sitting properly on the surface instead of hanging in the air (since I wanted to see where the Fido was while I was landing).

Below: The Base Lander touches down near one of Pol's mysterious spires. This location was designated Base Area 0, since it was Thomples's starting point.

Kurt: "Engines stopped. The Base has landed...like a glove. Propulsion systems are safed."
Thompbles: "OK. I'll drive us over. I'm looking forward to a chance to stretch out."
Kurt: "Readings show propellant levels in the Base are at 40%. Not bad for one landing from orbit and three suborbital hops."

We'll leave Kurt and Thompbles to there well-earned rest while we hop back to Bop to see what our four explorers there have been doing in the meantime.


Back to Bop

After poking and prodding the Kraken corpse for all the SCIENCE they could squeeze from it, Aldner, Nelemy, Hellou, and Emilynn continued their explorations of the dark surface of Bop. To begin, Aldner and Nelemy decided to drive to the North Pole (since there is often interesting terrain to be seen at the poles of moons and planets).

The high latitude meant that the angle of sunlight is very low, making it hard to see surface details in the shadowed areas. It also meant that Aldner had to halt the Fido occasionally to allow its batteries to recharge from the feeble sunlight (the rover also has RTGs that can help recharge the batteries).

The other moons of Jool are usually quite small in Bop's sky except when Tylo makes one of it close swings by (as below).

As our heroes approached the pole, it appeared that there was no strange peak or sinkhole there. The pole was located on a ridge running out from the side of one of Bop's big bumps. The view below shows the Fido approaching the pole area, and also shows a zoomed out overview of the area looking toward the East.

Aldner: "We're here, Little Buddy. The Navicomp says this sharp ridge right in front of us is the pole."
Nelemy: "OK, Dude. I'll make some foot prints and plant a flag."
Aldner: "AND get some surface samples. And be careful not to step right on the pole, or weirdness might happen. I'd hate to have to drive back alone."

Nelemy: "Yeah, this is definitely the pole, Dude. There are strange converging cracks. It almost looks like I can see stars in them."
Aldner: "Do NOT touch them...but see if you can get the flag planted close to the pole."
Nelemy: "Dude, you worry too much."

Nelemy: "Whoa! Ouch. Ouch."
Aldner: "What happened? Where are you?"
Nelemy: "Unh. I'm OK...but when I tried walking around to the other side of the pole, I went sliding down the slope. It was weird, Dude. I just sort of slipped for no reason."
Aldner: "Could be weird gravitational anomalies. Can you climb back up?"
Nelemy: "I've got my footing back. I'll just fly back up with my rocket pack."

Nelemy: "OK, the flag is planted. Get a picture of me hovering by the flag. Dude, the front illuminator on the Fido sure is bright!"
Aldner: "Roger. OK, I got the pic. Don't forget the surface samples. Take one from each quadrant around the flag if you can."

Below: Nelemy returned to the Fido's rear cabin and Aldner started the drive back south. The boys seem pretty pleased with the success of their mission.

After Aldner and Nelemy headed off to the North Pole, Emilynn and Hellou began a longer drive in the other Fido...which had previously been the Radiographic Fido. That Fido had already jettisoned the bulky X-ray sensor panels to make driving safer. The Fido has extra side-facing lights (originally used for illuminating the Kraken) that will make it easier to spot any interesting rocks on the surface nearby as they drive along.

Emilynn: "You sure you don't want to ride on top? You'd get a better view of the rocks."
Hellou: "No, thanks. I'm content with being strapped into the cabin watching the video feeds."
Emilynn: "OK. Let me know if you want me to stop so you can poke around in the dirt."

Hellou's first target was the lowest point on the surface of Bop. That point is located about 30 degrees South and 104 degrees East of the Kraken site...which sounds longer than it is because the lines of longitude are pretty close together as far north as the Kraken site.

Below: Emilynn drives the Fido down the slope into the low point depression...if you can call such large bounding bounces 'driving'. But even Hellou has gotten used to the long loping leaps of rover driving on Bop, which are actually quite gentle...for the most part.

Below: Hellou gathers surface samples and takes in the scenery at the lowest point they could find (elevation 2,005 meters). There were no mysterious blackout effects like they ran into at the low points on Vall, of course, because all points on Bop are located above the datum.

The Map view below shows the first part of Hellou and Emilynn's trip.

After Hello had sampled the low point extensively, our heroines headed off for their next target: The highest point on Bop. Below, the Fido climbs out of the low point depression heading east-southeast.

This part of the trip would involve driving about 14 degrees further South while moving about 75 degrees further East. I let MechJeb's rover autopilot handle this. The green beam in the image below shows that MechJeb is locked onto the waypoint placed at the high point (which is actually over the horizon with the beam pointing through the top of the mountain).

The image below shows the path from low point to high point. This is not a Map view, but is a far zoomed out normal view. For some reason the white markings on Bop were not showing up in Map view (possible some malfunction caused by Active Texture Compression). The highest point on Bop is part of the north rim of the large impact feature centered at 72°W and 4°S that has white markings on parts of its rim, which Hellou named Orc Crater. (This is not the same large impact feature that was previously explored on the opposite side of Bop...that was Goblin Crater).

Below: Hellou takes samples from the highest point they found on Bop: Elevation 21,743 meters, which she named Orc Peak.

For the final leg of their trip, Emilynn and Hellou headed South from Orc Peak to the equator near the center of Orc Crater. Again, I set a waypoint and let MJ handle this (but I set a low top speed for the drive down the relatively steep slope of Orc Mountain). I burned through this whole trip farily quickly...but I'm sure Emilynn and Hellou took a few weeks to do this with all the stops for surface sampling.

Emilynn: "We've just crossed the equator, Chickadee. And the ground has suddenly changed color."
Hellou: "OK, Emi. Stop here and we'll camp for a while so that I can sample this area well. Maybe I can find out why the center of Orc Crater has this odd coloration."

The map below shows the complete route of Emilynn and Hellou's rover trip from the Kraken Site (K) to the lowest point (L) and highest point (H) on Bop, then to the equator (X) near the center area of Orc Crater.

Hellou spent a lot of time exploring the central area of Orc Crater, but this marked the end of the exploration of Bop, and it was time for our brave kerbals to move on. After making sure that all the surface samples were securely stowed away, Emilynn boosted the Fido back to the orbiting ship (which was easy to do because they were located on the equator).

After rendezvous with the orbiting ship, the Fido still had over 28% of its propellants left. Emilynn docked the Fido to the top of their Vall Orbital Hab module, and then they transferred all the SCIENCE samples over to the main ship. Well...first Hellou insisted on taking a proper shower (exploring for weeks in a Fido is not the most comfortable situation), and THEN they transferred everything over.

Back on Bop, Aldner and Nelemy transferred all the samples from the other Fido to the Bop Lander, and then took off for the orbital station. Launch from the Kraken site put the Lander into a high inclination orbit. The right half of the second image below shows the plane shift burn to match the equatorial orbit of the main ship.

After rendezvousing with the main ship, the Lander had 35% of its propellant remaining (this was after its initial landing from orbit and two suborbital hops). Aldner docked the Bop Lander to the top of their Tylo Orbital Hab.

After transferring all of the samples and SCIENCE to the main ship, the Bop Lander Base and Bop Fido were both fully refueled...and then they were separated and docked to each other. These ships would be left in Bop orbit for potential use by future Bop exploration missions.

And, since the main ship still had more fuel than needed, the other Bop Fido was boosted from the Kraken site back to the main ship for refueling and storage in orbit for potential use by future explorers.

With the Bop exploration mission completed, Aldner, Nelemy, Emilynn, and Hellou prepared for their transfer to Pol. Again, the transfer calculators did not seem to do well predicting a transfer window between the two moons (both of which are in inclined elliptical orbits), but the trajectory that was found is shown below, using 89.6 m/s of delta-V.

With only eight of the nuclear engines active (some could not be used because their exhausts would impinge on lower engines), the enlarged Grey Haven Express boosted away from Bop.

Because the intercept with Pol was not optimal, the orbital insertion burn to place the Grey Haven Express into Pol orbit required about 204 m/s of delta-V.

No plane-matching burn was made en route to Pol, so the plane change was taken care of in Pol orbit with a burn of about 27 m/s. After that, smaller burns of 5.8, 6.3, and 14.3 m/s rendezvoused the Gray Haven Express with the orbiting Pol Station.


Participating at Pol

Thompbles: "Pol Base calling Grey Haven Express. Welcome to Pol."
Aldner: "Hey, guys! We've discovered alien lifeforms on Pol."
Thompbles: "No, Aldner. It's just me and Kurt."
Aldner: "Oh. Hey there, Fearless Leader. Imagine finding you here. How's it going?"
Thompbles: "Just fine, Aldner. Are you going to send down a scientist to help us figure out the weird terrain on this moon?"
Aldner: "In a while. But we just found an abandoned ship here in orbit, so we're going to strip it for parts first. We might get a good price for them at Jeb's Junkyard."
Thompbles: "Just be careful with it -- I'm still making payments on that vehicle."

The rearrangement of the vehicles started by separating Tug 5 from the Pol Station...and then separating the Laythe Transfer Hab and Pol Fido 2 from the Double-Tugs (Tugs 4 and 6) of Pol Station.

The section with the Laythe Transfer Hab was then docked to the top of Aldner and Nelemy's hab module to become part of the Grey Haven Express.

The next step was to undock Tug 4 from the Double-Tug, then roll it 45 degrees, and then re-dock it. The same thing was done with Tug 6.

Then the Double-Tug was docked to the bottom of the Grey Haven Express. This was done very carefully and slowly, paying close attention to the alignment, so that both docking ports would connect. This added two more Tugs to the stack, and also tied the rear of the stacks of Tugs together with its Double-Tug Adapter to strengthen the whole stack.

With this, the assimilation of Pol Station was complete. Tug 5, which only has standard docking ports, will be left in Pol orbit for possible use by future explorers. (The reason Tug 5 has only standard docking ports while Tugs 4 and 6 have Senior docking ports is because Tugs 4 and 6 have been back to Kerbin for upgrade and then returned to the Jool system at least once before...while Tug 5 has been attached to Laythe Space Station all these years.)

Later, Emilynn and Hellou transferred over to Pol Fido 2 and separated it from the Grey Haven Express to head down to the surface of Pol.

Part way through the descent burn, an empty X200-8 Fuel Tank that the Fido had been attached to was separated (this was done after the trajectory was already intersecting the surface, so that the tank would not become orbital junk, but before the trajectory was not yet aimed at the Base 0 area, so as not to bomb Thompbles and Kurt with debris).

Again, once the Pol Fido 2 got within two kilometers of the other ships, I brought it to a hover so that I could quickly switch to all the other ships and back to the Pol Fido 2 in order to have all the ships properly on the surface (rather than floating above the surface due to Pol's weird bugs). This allowed Emilynn to set the Pol Fido 2 down very close to the other ships.

The Pol Fido 2 landed with over 76% of its propellants remaining."

Thompbles: "Welcome to Sunny Pol Resort, ladies."
Emilynn: "Howdy, boys. I brought that scientist you ordered."
Hellou: "Oh! You even arranged for a landing site near one of those spire formations you were talking about. Thanks!"
Thompbles: "Well, the surface is thick with those things, so it wasn't hard. Come on over to the Lander and we can go through the samples that we've collected. Almost all of it is dirty ice, so I hope you won't be disappointed."
Hellou: "Dirty ice is what we expected."

Thompbles took Hellou out on EVA to examine the surface.

Thompbles: "The tan/yellowish surface layer is thin, covering much cleaner ice."
Hellou: "The surface layer is probably what got left behind as the ice slowly sublimated over time. The material looks like it might be a mix of organics and sulfur compounds, but chemical analysis will tell."
Thompbles: "The subsurface ice is quite porous. You can see in the trench we dug here."
Hellou: "Probably there were more volatile ices mixed in with the water ice, and those have already evaporated away. What about the spires?"
Thompbles: "They are also ice, but denser solid ice."
Hellou: "Hmm. The spires could have been cryovolcanic inclusions. As the more porus surface ice sublimated away, the ice in the spires was uncovered. It's just sublimating away more slowly...the top parts are narrower because they have been exposed longer."

Thompbles: "Has there been enough time for this much surface ice to have sublimated away?"
Hellou: "Could be...depends on the age of Pol, and the luminosity history of Kerbol. Some scientists even speculate that Pol may have been in an eccentric orbit around Kerbol before being captured by Jool, in which case it could have spent time closer to Kerbol or it could be from deeper in space...or both. Have you sampled the highest and lowest points on the moon yet?"
Thompbles: "No, but those are both south of here. I can drive you there if you wish."

So Thompbles, the most experienced Pol driver, took Hellou south to sample the extreme elevations of the moon. Emilynn stayed behind with Kurt, who taught her the techniques of driving on Pol (which she learned quickly, because they were similar to driving on Bop...only at even lower gravity).

Driving southeast across Siebold Planitia was easy, with its rolling terrain. I was trepidatious at first, expecting to run into buggy explosion-inducing terrain.....but everything went fine.

The image below shows a high overview of the area containing the lowest point on Pol (the dark depression), and the view Thompbles and Hellou saw as they approached the depression.

The lowest elevation found was 85 meters. The surface in that area was considerably darker than the normal surface coloring of Pol. Thompbles named the place Walker Depression after Walker Kerman, the first kerbal test pilot to fly the K-15 suborbital rocket plane out of Kermin's atmosphere.

Below is the Map view showing the first leg of Thompbles and Hellou's drive. They next headed further south where you can see the large mountains at the bottom of the map.

After traversing more of the Siebold Planitia (happily without mysterious explosions), they climbed the rim of a large crater structure (kind of an overlapping double crater), which Thompbles named Armstrong Crater, after Armstrong Kerman, another kerbal test pilot from the K-15 program. The high overview shows the rover's path from Walker Depression (and then, in a different color, where they went next).

Thompbles hung mostly to the inner wall of the north rim of Armstrong Crater when crossing toward the tall peak.

Below: When climbing the side of the tall mountain, they came across one of the somewhat rare round boulders that can be found on Pol. Hellou had Thompbles stop for samples.

The high point had several close-together ridges. Often, the other ridges looked to be higher...but when they drove over to check, they turned out not to be. The highest point they could find was 4,883 meters, which Thompbles named Armstrong Peak. Hellou planted the flag and sampled the surface.

After exploring Armstrong Peak, Thompbles and Hellou headed north, back toward base camp. Because of the overlapping double-crater terrain, this involved going down a steep slope, traversing a narrow flat area (below), and then driving up the even steeper north rim of Armstrong Crater.

Below: The leap over the north rim...followed by a very steep descent on the other side. It got a bit hairy, but Thompbles managed it OK (if things got too steep, there was always the option of firing the rocket engines and hopping out to the flatter plains...but this wasn't necessary).

Then our intrepid explorers left the southern mountains behind them and headed mostly north toward Pol Base at Area 0.

Finally, Thompbles and Hellou return to base camp. The four kerbals spent several more weeks exploring Pol. When Hellou wasn't having somebody drive her around to collect samples, Kurt and Emilynn were doing rover races ...er...I mean they were gathering additional data about rover behavior on low gravity airless surfaces. And the videos they made were quite popular back on Kerbin.

That's it for this episode...except to mention that Aldner and Nelemy were entertaining themselves up in Pol orbit, getting the Grey Haven Express ready for its return trip to Kerbin. Because of the staggered arrangement of the nuclear Tug motors, they would be using four of the tugs (eight engines) for the return trip, so engines were disabled and propellants were moved around accordingly.

Next Episode: The boys of the original Laythe Expediton Crew (plus the two Vall girls) will be heading back toward Kerbin. And the New Laythe Crew (whom I've mostly been ignoring...but I'm sure they have been doing useful things) will get their Mallard Seaplane to play with.