Monday, October 5, 2015

KSP: Keystone Crew Delivery Vehicle.

So, as much as I like to cobble and tinker with Kerbal Space Program, there is a method to my madness as I juggle parts around. One of the things that I like about the program is that it lets you address the same type of issues that the National Aeronautics and Space Administration, the Russian Federal Space Agency, and the Chinese National Space Agency have to deal with each day. While the US arguably has the most advanced space program currently going, I am much more drawn towards the Soviet/Russian Soyuz program and its overall engineering philosophy. I am also a longtime fan of the KSP mod Home Grown Rockets. I have flown a great many missions with the Kerbal "Soy Juice" command capsules fitted with "onion" pods, and have built several large and complex space stations around the craft's abilities.

Something to note, the Soyuez works on a very dependable, but disposable working principle. When launched, the craft itself is composed of three parts, the "Orbiter Module", the "Reentry Capsule" and the "Service Module". of the three components, only the Reentry calsuel comes back to earth, and even that is a rough entry. The whole craft is a one-time use, and can carry only three people.

If you're interested in some more details on the craft and it's functions, I highly recommend the ESA's videos on the Soyuz Launch, Docking, and recovery.

In the late 80s, and through the first decade of this century, the RFSA was heavily invested in research into a replacement for the Soyuz craft, with a heavy emphasis on reusability, as well as a less violent reentry back to earth. One of the more prominent designs to come out of the project was the Kliper. Using lessons learned from both Soviet/Russian space experience, and a new partnership with the European Space Agency, the Kliper was seen as a larger, more effective means to move men and equipment into orbit around the space station, and also take on additional missions like satellite position, orbital repairs, and other scientific research.Funding, however, was the undoing of the design, and the ship is still stuck in the design phase with no funding for advanced development.

I was drawn to the kliper design because it uses a classic rocket to reach orbit, but also uses airfoil/glider design to return to each in a much more complete way than any of the Russian predecessors. Also, by using a glider, rather than a bell (the shape of the reentry module on the Soyuez), the return is actually far less traumatic and more controlled.

Early Kliper concepts made the craft out to be a super compact space shuttle, complete with landing gear. Later designs, however, incorporated lessons learned from Russian experience in hard landings (Landings on ground, rather than water) and created a much lighter craft that could glide to a safe speed, and then deploy a large parachute for the final stage of the decent.

Again, the major design point here is the complete reusability of the entire craft. Rather than having to rebuild a completely new vessel  each time, the kliper can be inspected, refueled, and set atop a new rocket. The advanced computers, avionics, radars and instruments are preserved for another mission.

I have dabbled in a fully functional, rocket launched space-plane before, but never liked the results. The parts available in KSP were just limiting enough that I wasn't able to build something that both worked and didn't look unbelievably ridiculous.

My most recent project, however, took some of my lessons learned, and a new take on design philosophy,

My goal, I reminded myself, was not to build a passenger-capable version of the X-15, and while the klipper was not actually within my grasps, a controlled reentry and parachute landing by a lifting body craft was. At the end of the day, I wanted something that could carry at least 3 crew, reach orbit, and return with most (or all) of the instrumentation, control systems, and air-frame intact.

There really wasn't any debate on what from factor to start with. The Mk 3  (space shuttle) set was too large. If I went that route, I'd be looking at rebuilding a full shuttle, which is what I specifically didn't want to do. Alternately, the Mk 1 command pod was too small (crew of 1) and had no lifting body abilities. In point of fact, the Mk 1 would be a step backwards in every sense of the word. So, that left us with the Mk 2 series of parts.

The Keystone CDV (Crew Delivery Vehicle)

I drew my name from the Soyuz, which is Russian for "union". "keystone seemed to work for what I was looking for.

Vessel information
Weight: 8.0 T
Length (nose to docking ring): 7.4m
Width: 2.7m
Delta V: 919 (atmo) / 1160 (Vac)
Crew: 0 (Drone control unit)
Passengers: 4
4x 24-77 "Twitch" Liquid Fuel Engine

The Keystone is capable of transferring 4 passengers into high Kerbin orbit, but does not have the thrust (by itself) to transit outside of orbit and move to another body (Mun or Luna, for example). Its primary mission is the reployment and return of crews to other orbital facilities, or waiting orbital craft deployed in unmanned launches.

The walk-around:
As you can see in the nose detail, the ship uses multiple Place-Anywhere 7 Linear RCS Port thrusters for orbital maneuvering.

I'm using a Mk 16-XL parachute for the nosecone and final recovery system, and the front quarter of the craft is the fuel tank, one of the MK2-to-1.25M Adapter tanks, And that mounts to a MK2 drone core control unit. 

The Mk2 Cargo Bay (CRG-04) is actually serving as a support bay/module for this vehicle. It does not have cargo carrying capabilities.
The bay contains, and Advanced Inline StabilizerFL-R25 RCS Fuel TankZ-1k_Rechargeable_Battery_Bank, and 5 x OX-STAT Photovoltaic Panels. Communications are handled by a single Communotron 16 mounted on a Cubic Octagonal Strut, whcih is attached by the center of the Z-1K. Thefuel for the main engines is conveyed by two FTX-2 External Fuel Ducts.

The rear aspect of the Keystone shows a good perspective of the crew compartment, the docking rink, and the flight controls surfaces, as well as the 4 engines. 

The 4 passengers are carried in a Mk2 Crew Cabin, as I said before. Maneuvering and attitude control is handled by a combination of the Reaction wheel, the RCS system, and the four A.I.R.B.R.A.K.E.S.

The Docking port is projected out past the ends of the A.I.R.B.R.A.K.E.S. by an (emptyFL-T100_Fuel_Tank that is used here for a structural tunnel and mount for the 4 main engines. During initial trials, I mounted the docking port to the back end of the hull directly, and the engines to  Cubic Octagonal Struts, but it was quickly realized that during landing, the engines were being destroyed by the otherwise slow impact, the docking port was rated for that type of impact so I let it be the "bumper" for the ship on landing.

This slightly enlarged image gives you a good view of all the critical systems with the control flaps extended into full break mode.

Craft file: Note, this includes the 3 stage launch vehicle. The launch system is a stock reproduction (in concept) of the Soyuz rocket.

1 comment:

  1. I enjoyed the article, good work! (There were a few typos in there, but that was all I saw wrong, keep it up!)