Solar Pathfinder Program

[Kolenka]

Jeb has had lunch on the Mun and Minmus. Probes have been sent (and crashed) across most of the Solar System. There are manned station cores around the Mun and Kerbin in preparation for something bigger. It is time for Kerbalkind to enter the Solar System (apologies to Quayle Kerbal).

More detail to follow.

Missions:

Mission 1: Duna Express

[Kolenka]

Mission 1: Duna Express

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Crew Roster (4): Bill, Erler, and Shelfrey (plus a redshirt)

The first mission of the new interplanetary project is an express launch to Duna. The goal of this mission is to demonstrate the first generation technologies required to take Kerbals to other planetary bodies. This includes a first generation planetary lander designed to operate pretty much anywhere, although Eve and Kerbin are one-way trips. Also included is a first generation interplanetary drive with a custom ultra-heavy lifter. Mistakes will be made, but we will learn from them.

First up, the lander: 32t of habitation and fuel, roughly 2500 dV in total (vac). Space for 7 kerbals. All mounted on top of a repurposed launch vehicle used for station crew supply. After doing some early tests of the landing vehicle itself at KSP, it gets launched into orbit.

Once in orbit, we find that we have a bit of dV left in the launcher after reaching a 95km parking orbit. Perfect. We can use that up as part of the docking maneuver.

Second up, the drive section. A monstrous 92t of flying fuel can, with 6 nuclear engines. Without a payload, it has a dV of over 9000. With the lander attached, the dV is still comfortably over 5000. It is expected that later designs will be the workhorse of the Solar Pathfinder program.

The engineers, overworked from the custom launcher required, have failed to provide adequate documentation of the work done here. But they assure me that the documentation will be dredged up. One of the final test launches turned real when the launcher managed to just barely get the payload into a 72k/95k "parking orbit" when the launcher ran out of fuel and was jettisoned. It was decided to bring the periapsis above 80k and make a docking attempt, using the drive section's fuel. The docking attempt was a bit rough, and there were some issues with rotation of the lander and the fuel tanks in the drive section.

At the end of the maneuver, the final mass of the vehicle is just shy of 120t, due to fuel spent by both the lander and drive section tweaking the orbits. And we are left with 4800 dV in the drive section. Thankfully RCS is still half full in both the drive and lander sections. More than enough for this particular mission. The crew is currently in a parking orbit, awaiting word from mission control on the burn to exit orbit and enter a transfer orbit to Duna.

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Engineer's Post-Launch Report: We've already identified a couple issues that we should fix in the second generation lander. The ladder system doesn't get us into the cockpit on its own. This will prevent us from using the first generation lander on higher gravity targets, so we should fix this in the Mk II. We decided that since Duna was the first target, to go ahead with the design flaw unfixed. Once the lander was in orbit, we realized we'd forgotten to place safety lighting on the lander. Not worth aborting the mission for, try to fix in the Mk II. Bob won't be able to sleep without a night light.

The bigger problem we face is that the chutes are not re-packable, and we sent more Kerbals than fit in the detachable crew module. The original re-entry plan called for separation of the crew module from the habitat module. This spells doom for one Kerbal if we proceed with this plan. While the lander's design should survive Kerbin re-entry, it is currently unknown exactly how we expect to proceed. We will need to modify our plans for when we want to use the chutes (2 drogue, 4 radial, 1 cone) during this mission in order to secure the safety of all crew. Fortunately, it will be months before Duna Express reaches it's destination, giving us plenty of time to perform experiments with a second lander on Kerbin to determine the minimum number of chutes we can safely land with on Kerbin, and how much fuel we'll need to perform a safe landing. At the very least, it will give Jeb something to do. It is not recommended to tell the crew at this point in time about the danger. This is a must-fix for the Mk II.

Edited February 4, 2014 by Kolenka

[Kolenka]

Duna Express: Year 6, Day 283

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The crew has completed their Kerbin escape burn. They report that after a long, 6 minute burn, they are on intercept. A second burn will be required to adjust the intercept point to prepare for aerobraking. At this point, it is expected that the interplanetary drive will be a little under half full on return to Kerbin. The engineers will have some time to prep a refueling rig, and additional payloads in addition to the Mk II Lander.

Now that Duna Express is on its way, the engineers got to work on the problem of getting the lander back safely. The first test was an attempt to see if the lander could be brought in using the radial parachute and minimal fuel. During the attempt, the primary chute was deployed, and upon opening, tore the crew capsule away from the rest of the lander, which crashed horribly. No crew lost.

The engineers have put together a procedure to repack the chutes with a little effort. In other words, they finally read the manual on the chutes they installed on the lander. So the second test was a landing with all 7 parachutes. Despite using all the parachutes, the drag chutes deploying tore off the RCS fuel tanks from the lander, along with the radial chutes. Excess fuel had to be burned in order to bring the lander in safely. The tanks will likely need to be topped up before landing by the drive section.

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Engineer's Notes: The re-entry tests prove that the lander will get the crew back in one piece. The chutes are not sufficient to bring in a 32-ton lander on their own however. Further tests might be a good idea to see how the parachutes work with less fuel on board the lander, such as an empty fuel case. Also, we need to look at the Mk II, a refuel rig so we can reuse the drive section for the next mission, and start putting together a science payload for the next mission. Either a rover or some probes.

[Silverchain]

Good luck with everything, parachute landing on Duna is hard - the air is so thin that results are quite variable depending on exactly where you're landing.

[Kolenka]

Good luck with everything, parachute landing on Duna is hard - the air is so thin that results are quite variable depending on exactly where you're landing.

Yeah, I expect a fair amount of fuel used to land, and mostly just using the chutes to slow down a little and save fuel. The real concern was more: what would the chutes do on the return trip, and how much fuel do I need if the chutes aren't enough? The original return plan was apparently to jettison the hitchhiker module to its doom, which isn't gonna work, for obvious reasons.