A decoupler too far: Almost lost in space (Lots of words, Lots of pictures)

[Randazzo]

Having begun the first stage of exploring Tylo last night during the same launch window as the Vall ship, the plan was to send a mapping probe "Magellan" to locate a suitable landing site on Tylo that was elevated and contained a pocket of Karbonite. Following this, a vessel carrying the Lander and crew would launch at the next window, "Cortez". The Cortez lander would be equipped with a small Karbonite mining array and a fuel converter to refuel on the surface rather than sending an even more ginormous vessel. As the combined vessel would be prohibitively large (117 tons with fuel), the lander and engine core would be launched separately. Utilizing KAS, struts would be created between the two modules once docked to provide additional strength as a single docking port was suspected to be too flimsy to support a connection between such heavy vehicles. Cortez I and II were prepped and ready, and the De Champlains crew was tapped for this mission as well.

From the very beginning, things began to go wrong. Magellans gigantor solar arrays were mounted in such a way that they extended partially beyond the lower edge of it's main fuel tank, but still well above the engine bell. However when the final orbital stage was jettisoned to free the main LV-N engine on the satellite, the ejection force of the engine fairing was enough to blow off the solar panels as well. Now only able to generate power while the LV-N was running, Magellan was no longer capable of performing it's mission. An emergency vehicle, "Santa Maria", was hastily constructed and given a number of 1x6 solar panels to be attached (again via KAS) to the Magellan, and Bill was sent up to perform the spacewalk. This went swimmingly, and the Magellan was once again equipped with solar panels and able to complete it's task. Bill returned to KSC, and Magellan went out with De Champlain. A polar orbit was established over Tylo, and mapping commenced. The De Champlain's mission was completed while a map was created, and a suitable site was located near the equator.

Cortez I and II were being prepared for the next launch window which was shortly after De Champlain returned. Both vessels were sent into orbit at 150 Km to rendezvous, where another spacewalk was performed after docking to set up the struts. Now stabilized, the final orbital stage still attached to the engine core carried the completed Cortez to a higher orbit for departure. There were no complications at this stage, but there was concern about the stability of the craft during the planned aerobraking node over Jool. As luck would have it, Tylo would be in a position to be encountered directly after aerobraking if done properly. This would remove the step of having to establish a Jool orbit and then transferring. The encounter did not quite turn out as planned however, and a retro burn was required to establish a Jool orbit after all. The weight of this decision would be felt later, but for the moment all seemed well.

Transferring to Tylo and achieving a stable orbit (at 10km to reduce landing Delta V requirements) was significantly more costly than expected, leaving the crew in an all-too-familiar situation of not having enough fuel in the engine core to return home. Despite having marveled at the large Delta V requirements of putting Magellan into orbit, this small detail had slipped quietly out of mind until Cortez arrived. Following my tradition of making happy mistakes, I also realized at this point that somewhere along the planning process, I had gotten my Delta V budgets for landing on Tylo mixed up with Laythe. This resulted in a lander essentially built to land and take off from Laythe, meaning it was going to have a fuel surplus once it returned to orbit. This could either be transferred to the Atomic engines, or the remaining fuel from the core could be transferred to the Lander to give it a large enough budget to return. This decision would be made after the two modules rendezvoused after the landing.

I had read plenty on how challenging Tylo was to land on, but I had also spent some time doing practice runs with powered landings on Kerbin. As challenging as Kerbin landings were, it was nothing compared to Tylo. Not only did the Cortez lander overshoot the chosen LZ, I ultimately ended up landing at the bottom of a crater instead of a high point as desired. The impact was a little harder than it should have been, just barely getting under 10 m/s but miraculously the landing legs didn't break and the engines didn't blow up. If the lander had been built to what I believed was the Tylo Delta V budget, I would have ran out of fuel. As they say, it is better to be lucky than good.

With the terrifying landing over with, the explore contract was completed along with a flag planting contract, pictures were taken, and drilling commenced to begin fuel production. After all of this, the mission was brought to a screeching halt by a decoupler. Intended to blow off the mining array during ascent, it's primary function actually turned out to be preventing the LFO converter from having a fuel path to the tank. No fuel could be created since the converter had nowhere to put it, and this could not be manually bypassed. I -had- actually thought of this and connected it via a fuel line, but this did not work. The crew was stranded, and no happy accident would save them this time.

A rescue plan was immediately thrown together, sending a mobile mining and fuel refining platform to fill the Cortez Lander. Dubbed the "Dominguez", the probe was slapped together in a hurry and launched as soon as possible. Once again, a Tylo encounter was possible after braking, and since I apparently do not learn from my mistakes, I went for it. The resulting encounter was even more ridiculous than the Cortez's attempt. Corrections were made, and orbit was established. This being a one-way trip, fuel was not a major concern, but the lander core was equipped with a docking port for Cortez to take it's remaining Fuel after rescue. Being optimistic, I sent Hans Kerman out to place an LZ flag for the Dominguez to prevent any accidental landing-on-top-of-the-Cortez from occurring. Hans was then moved a safe distance away from the flag.

Given how poorly I performed the first landing, Mechjeb was utilized this time in hopes of a more accurate landing. It was more accurate, but still missed by over a kilometer. The rovers ingenious deployment system of "knock over the lander base" worked perfectly. Hans ran a kilometer and a half to man the mobile platform and siphon off the little fuel remaining in the lander there. Returning to the site of the Cortez, the drills were stripped from it's array and added to the Dominguez rover to speed up the process, and fuel production was begun. All told, it will take a week of Kerbal time to refuel the lander. The mission concluded here for tonight, ascent and rendezvous in very low orbit will be tomorrow nights fare.

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Edited February 18, 2015 by Randazzo

[Wabbit]

Take that, Tylo!

[Sampa]

Wow, I like the landing of the Santa Maria! Talk about pinpoint landing!