Kerbals down the Mohole

[Tw1]

Equipment testing

Back in '0.21, I had plans to visit the Mohole. I'd even created and tested a special vehicle- the Mantis Shrimp Climbing Rover- to get me down to the bottom, and out again.

Here it is in a munhole. Traveled up and down many times.

However, nothing came of these plans. Until now.

The Mantis Shrimp- from 0.21 to you!

I'm going to Moho.

I pulled a copy of the Mantis from old 0.21, and began testing on a convenient vertical surface, in simulated mohovian conditions. Issues new and old raised their head, and I applied new, 0.90 techniques to fixing them.

Before long, the rover was behaving itself, well, reasonably.

Switching back to Kerbin gravity makes it not work.

Once I was happy the rover would drive and climb well on Moho, it was time to develop a lander. I followed standard lander guidelines, high rotation power, wide at the base, low CoM, that sort of thing:

The 3.75 m parts made it simpler to build a lander big enough to carry it. Kerbin testing showed the rover could re-dock to the lander if necessary. And also that the ladders worked.

The pod is mounted on a docking port so it can be removed from the rest of the vessel should rescue be necessary.

All systems go. Time to make a rocket!

Edited March 10, 2015 by Tw1

[Kieve]

Haha, awesome. Is that one grapple going to be long enough though? I thought the Mohole was pretty deep.

[Tw1]

Rocket business

If you look at the Lander, you'll notice a lack of central bottom connection nodes. For the Mun mission pictured above, I solved this by having two rocket stacks, with the Lander fitted between then. But I use FAR now (FAR is cool) and want to shield this Lander with a faring.

The simplest solution was to mount the Lander upside down.

I built a nice big rocket to take the 100 ton Lander into orbit.

Decoupling the first set of boosters was always dramatic.

I'm pretty sure that was the decouplers exploding earlier. Otherwise, the rocket was unharmed. It happened every single larch attempt.

However, as it'd been a while since I last made a lifter, I'd forgot FAR reduces the launch delta V, and built the rocket to stock standards. I got into orbit with two core lifter stages still there.

There was a central S3 KS-25x4, but that was crushed by the outer boosters as they decoupled and flipped. Opps...

This seemed a bit wasteful- the upper stage uses a KR-2L, rather than something efficient, and suited to interplanetary travel. My original plan had been to dock the lander to a fuel tanker, but with some revisions, I could send up everything in one hit.

I reverted the flight.

I traded the KR-2L for the big nuclear engine from KSPX.

Here, we have Genely kerman inspecting the discarded stage

The idea was to use perikerb kicks to break up the burn. But this would not go so smoothly.

When the ship reached the burn point, the engines would not fire. The throttle would not budge.

I tried switching back to space centre, rebooting the game, nothing changed it.

I speculated something had gone wrong with the Lv-bb. Tweakscale had changed its size, and that part had had the odd glitch in the past. Nothing like this though.

In an attempt to find a solution, I blasted of the Lv-nb with wack-a-kerbal had my engineer safely remove it.

I then used KAS pipes, (originally intended to connect to a fuel tanker) to link the top tank to the lander's central tank, and activated the lander's engines.

But it was to no avail. The throttle was still stuck, the engines wouldn't fire. She was dead in space.

With reverting no longer an option, the only one thing I could do was schedule a rescue for these guys, and call the back up crew.

Launching this third one gave meed the opportunity to make a few more final changes. I traded the Lv-nb for more fuel, and connected the upper tank to the lander with stock fuel lines. I also added parachutes to the pod, just in case.

This launch went more or less flawlessly, and the B-crew made it safely to a 200 km parking orbit,

The B-crew: Aldner the scientist, Esden the engineer, and Samwise the hobit our pilot.

I checked the throttle many, many times. All systems go. They dropped the last lifter stage, and began perikerb kicks.

Here's Esden inspecting the discarded stage.

So thrilled that his team was called on.

Next, I've got to get them to Moho.

Haha, awesome. Is that one grapple going to be long enough though? I thought the Mohole was pretty deep.

One grapple would be nowhere near long enough. But the grapples are only there for when the rover needs to be held in place. For the rest of the trip, the rover will be pressed to the side using force from two engines.

Edited March 10, 2015 by Tw1

[Tw1]

Interplanetary stuff

Moho, as many who've done it will tell you, is a tricky little ******* to get to.

It takes 2 metric *beep*tons of delta V to get there and back, it's got significant kerbin relative inclination to throw you of, it has a small SOI and moves fast, making getting an encounter tricky. Setting this up was more tricky than it sounds.

I broke the burn up into a few stages, ("periapse kicks"), timing the last one to bring me to periapse right at the time for transfer. But this didn't stop my planned maneuvers from getting all mixed up when 4 times timewarp cased the fuel tank to break off, and I quickloaded to a point earlier in the burn.

Fortunately, I still managed to get a reasonable encounter after cocceterng at the descending node.

Upon arriving in Moho's SOI, I made a correction burn to make sure my trajectory would pass over the pole. Then, I let my kerbals out for a bit.

This is essential when you only have a small pod.

THey hung out above Moho for quite a while. During this time Aldner ran the science experiments on the fuel tank Module, and transfered them to the capsule.

Then It was time for the breaking burn.

Before long, the upper tank was exhausted. I fired the decoupler, the turned, using a small burst of thrust to get out of the way.

Then continued with the burn.

That image was taken from "Landre"'s underside camera. They did say we'd be getting proper vacuum thrust effects a while ago. I hope this hasn't been forgotten.

Then, I performed to smaller burns, one to perfect the polar inclination, and one to prevent crashing into the planet.

And one final one to circularise at 100Km.

In total, the trip cost about 6500 delta V, a little more than I had allowed for. Getting back is gonna be tight.

Now to get them down there.