The Pathfinder Files

[Vagrant203]

I'm going to try something a little different. Most mission reports I've read have focused on a particular expedition or save. The Pathfinder Files will focus on the development and implementation of a specific vessel type, Long Service Vessels. 

So far, I've only developed two versions of this vessel in two separate saves, both bearing the name Pathfinder, thus the name of this thread.

I've mentioned the first in another thread, but there are differences now. I'll now be using "generation" to refer to how many saves have featured LSVs, and letters to refer to the iterations within a save. This is a marked departure from previous terms, which used generation to describe tech level and letters to denote an entirely new ship.

This first post will cover the launches, orbital assembly, and some operation within Kerbin's SoI, of the second generation, model B. The only mods in use at the moment are ReStock, ReStock Plus, and SCANsat.

The first launch conveyed the drive section, command center, and crew quarters. Like the first generation, a Mk1-3 command pod serves as bridge and probe control. A four-seater Hitchhiker pod has also been carried over, supplemented by two Mk1 crew cabins for a total of eight passenger seats serving as habitation. The two additional cabins have been mounted atop structural fuselages, with a service bay and a slanted nose cone atop them for aesthetics. One service bay features an OKTO probe core and an avionics hub, while the other is populated with batteries. Each cabin also has two jr docking ports, mounted radial top and bottom. On the bottom of each fuselage are a 1.25m reaction wheel and a Caravel engine from Restock Plus, a recent acquisition which has fast become a favorite for its balance between Isp and thrust strength. Behind the Hitchhiker is a central Rockomax tank with fuel ducts leading out to two outboard fuel tank stacks, each featuring a Poodle engine for the best Isp. There are more service bays with monoprop tanks, batteries, and one stack of 0.625 reaction wheels. There is also one midsize dock port at the aft, and a jr size on the nose of the bridge.

There are a few peculiarities to this arrangement. Under typical operation, the central tank is drained first, as you would expect. To my surprise, on refueling, the central tank also pulled from the outboard tanks, despite the fuel ducts and spaced decouplers, when using "in." I resorted to using "out" on the tanks to be drained and decoupling them immediately, one by one. In the future I'll try refueling with only the central and delivery tanks selected. ∆v calculation also behaved strangely, flickering between eight hundred some and three thousand. This was likely an odd interaction with MechJeb's "differential throttle" function found under utilities. Shutting off the Caravel engines was an easy fix, giving the accurate reading of three thousand running on Poodles. The Caravels were great for the launch and may be useful, or even necessary, for other high-power situations or simply a shorter burn.

Glamour shot

Service bays opened, angled towards sunlight, best shot to see details

The second launch covers everybody's craving, sweet glorious Science! There's a research lab, Science Jr, goo, thermometer, barometer, and, last but certainly not least, a SCANsat Multispectral Analyzer, which I just love. You can even find [classified data redacted]. The biome feature is neat too, although that function can also be filled by the lab's KerbNet access in case ya didn't know. There's also some more RCS and monoprop (forgot reaction wheels, whoops) and both ends feature a midsize dock, one of which is occupied by the drive section. There are also two radial docks in both mid and jr varieties.

For now, these sections enable Pathfinder to meet specs within my tech level. Once I've unlocked ISRU technology, a pair of engineers will join the crew with a refinery section and a mining drone.

Speaking of drones, the third launch is an RCS tug I've dubbed Retriever, following a theme of dog breed names for kerman's best friend. It features both jr and mid ports and six extending Communotron 16s, providing extended control range and transmission of research when not being used as a tug.

The next launch will be a probe lander and two sample return packages. The probe will have all the experiments the lab section does, excluding the SCANsat and materials bay to save mass and enable a return trip.

Edited March 9, 2020 by Vagrant203
Typo, screenshots

[Vagrant203]

It's been long enough that I'm writing a new post as opposed to editing the beginning operations into the previous.

The tug drone mentioned in the previous post was not very effective in its first iteration. I have yet to design a new one, but I do have the large inline cans of monoprop unlocked now.

I've also managed to unlock nuclear propulsion. This will be heavily relied upon for the C variant of this generation's Pathfinder. The class B will remain within Kerbin's SoI, while the C will be going interplanetary.

Also benefitting from nuclear propulsion is the Bloodhound science lander. So far, the Bloodhound has landed on Minmus, and returned to orbit, three times. With the extra margin of ∆v, it was decided to feature the full complement of unlocked science useful for landers. The inbound trip and the first landing were enough to stock the lab with its data quota, and the other two had their data transferred to a sample return drone.

Said sample return had managed to pass beyond transmission range at apoapsis after leaving Minmus SoI. Some confusion regarding control points burned enough of the return's ∆v that this had effectively stranded it for the moment. However, I sent a Mk1-3 pod with nuke engines to guide it home, manned by everyone's trusty pilots Jeb and Val. Mission Control got tired of the sibling squabbles early on, but they remained mission effective and brought home 723 points of Science! and some strays they picked up on the way back, and managed not to ruin the vacation of the three tourists they brought along for the ride, probably due in large part to being in a separate pod.

Spoiler

I typed this post on my phone whilst waiting for the last launch of the post to load. If you read this post and saw the blank instead of the actual amount of retrieved Science!, that's why.

 

Edited March 10, 2020 by Vagrant203

[Vagrant203]

It is with great pleasure that I announce that this space program has successfully researched ISRU technology. The final stretch of research was made possible by data retrieved by a Mun lander, which bore a pilot, scientist, and a tourist. A 250-scale refinery has been delivered to the Pathfinder 2b in Minmus orbit, and will soon be followed by another small section dedicated to solar panels and thermal control systems, with a few high-capacity batteries for good measure, along with a drill lander with a probe core and seating for an engineer.

 

Spoiler

This spoiler was supposed to be at the bottom, but I can't delete it or click and drag it on my phone.

I managed to install Stockalike Station Parts Redux, without IVAs.

Model 2c is already on the drawing board, retaining the functionality of 2b including the refinery. In addition, there will be a centrifugal habitat section to help the crew maintain some level of adaptation to gravity.

Edited March 11, 2020 by Vagrant203

[Vagrant203]

*long exasperated drawn out sigh*

Another save has suffered the damned "Value cannot be null" death. Therefore, this post marks a transition to generation 3 and perhaps a bit of a hiatus for the Pathfinder Files.

[Vagrant203]

Whilst unlocking a few nodes of research, I've found a part provided by Stockalike Stations that provides a probe control point, in Advanced Flight Control. This would provide the first step of Pathfinder 3a, with the next being to unlock docking nodes through Miniaturization. It's likely I will also wait for Heavy Rocketry and Fuel Systems before deploying the first section.

[Vagrant203]

I'll post some screenshots later, but Pathfinder 3a's command/propulsion module has been launched. 3a is an attempt to fill the same roles with simpler technology.

This model utilizes fixed small solar panels, jr-sized docking ports, and perhaps the biggest difference lies in the fuel tanking and mounting. Other LSVs have utilized the spaced decouplers and 2.5m fuel tanks. This version has side mounted FL-T800 tanks and a central 1.875 half-tank.

The downsizing has led me to consider other methods of cutting down on mass and cost. Generation 3 will explore the use of a four-kerb crew and will also forgo adding a research lab to the vessel, as well as swapping to the lighter refinery once unlocked. More research will be devoted to communication so that experimental data can be transmitted back home and the crew can immediately rerun the experiment to store the results in "hardcopy." 

Edited March 12, 2020 by Vagrant203

[Vagrant203]

Because I have a new computer, Pathfinder is now generation 4.

[Vagrant203]

LSV4a is go!

This marks the first LSV I've designed with the REMEMBER modpack (although I left out KCT because *fart noise*.) 

Obligatory glamour shot

Better details

Stats and other technical details

There's a "Pier" station core beneath all that, crewed by two pilots for the probe control goodness. I've included storage for all three resources added through USI-LS, a small greenhouse and two recyclers. The engines are, as you may have guessed, good old Poodles. There's a central FL-T800 and two outboard, as well as two outboard tank adapters going from 1.25m to 1.875m. There's a midsize docking port on the central tank as well.

[Vagrant203]

LSV4a has been decommissioned due to inadequate life support reserves. LSV4b was short-lived as well, with only a scant 1500 ∆v once it had been joined by an ISRU refinery, despite using the largest 2.5m tank and four of the largest 1.875m tanks. 

4c is being brainstormed, likely going back to a smaller form factor for all parts, even the refinery despite the hit to efficiency. I have definitively settled on excluding the research lab and trimming the crew to four, two pilots and one each in science and engineering specializations.

[Vagrant203]

It has once again been quite a while. I've been playing other games, but have recently returned to KSP with a pure science playthrough. With this new save comes a new generation of Long Service Vessels. Details and screenshots of LSV5e to follow.