Station Aleph - A first Space Station

[Concentric]

I started Station Aleph a little while back (really just a few days, possibly a week at most), in the middle of the MunTherm mission where I escaped Mun in the wrong direction. While I'd been waiting for that to return for its aerobrake, I had researched the Basic Jet Engine, and the first Docking technology node. After some messing around with SSTO spaceplanes, I decided to make an orbital spacestation. Everyone's doing it, right?

At that time, the only probe core I had was the StayPutnik 1. I put together a structural core with girders, girder-FLT connectors, a reaction wheel, a small fuel tank, an RCS tank, some RCS thrusters, several Z-400s, a few 1x6 SP, eight shielded docking ports and some struts, and put an attempt at an RCS tug on top of it, then strapped it to a big rocket and launched it. At first, I put it into a 100km circular orbit, and deorbited the rocket. This didn't last when it came time to dock other things to it... I didn't check the location before launching following pieces after it, and soon decided it needed to be higher.

The next thing I wanted to put on was the Habitation Module. Oh, that's easy, I thought to myself. Just stick a couple of Hitchhikers together, put an adapter and shielded docking port on each end, connect a couple of rockets radially, lift it to orbit, and it'll be just fine. So, that's what I did. Hitchhikers, adapters, docking ports, batteries, ladders, Hydraulic Detachment Manifolds, fuel tanks, reaction wheels, StayPutniks, Rockomax mini radial rockets facing both up and down, radial launch stage, and away we go. But, as you may have noticed, something was wrong. Something that would seriously hinder my docking chances. I had neglected RCS.

Thinking it salvageable, I decided to go ahead with the mission anyway, planning to use the tug to dock the module. To prepare for this, I tried maneuvering the tug a little, and came up against a small problem. The tug contained the only probe core on the station at that time, so undocking left the station core as debris, which was irritating to redock with even immediately. So I needed to put another probe core on the station. As I also needed to put a tank on there, I chose to kill two birds with one stone, putting a probe core on the tank, so it could maneuver itself with RCS. I put the tank together - two Rockomax-32s sandwiching a large reaction wheel, capped by flat Rockomax-FLT adapters with RCS tanks on. Some static solar panels, some lights, some deployable solar panels, 16 Cylindrified RCS tanks, lots of linear RCS thrusters and some Z-400 batteries. Then a docking port on the bottom, StayPutnik on the top, and docking ports at a measured distance from each other on the tanks, for a binary docking to the station core. Stick a dirty-great rocket under it that had far more fuel than necessary and launch.

At this point, I was looking to set up some rendezvous - first the tank with the core, then the Hab module. But down at a 100km orbit, things looked awkward, and took a long time. So I raised the core to a 200km orbit and called it good. Not long after, the tank was up there too, and my first real orbital docking from separate launches was a binary one that went pretty much perfectly. While I was doing that, Bill Kerman, who'd come up with the tank so I could deorbit its launch stage again, was falling into the atmosphere never to be heard from again. Don't know what he was thinking, he had parachutes after all. You take your eyes off that guy for fifteen minutes and he's off killing himself. (I really should have just matched the tank's orbit instead of doing the docking while Bill was descending. The launch stage fell to the planet, but I forgot Bill's little ship was also on a terminal descent when I switched back to the tank to dock...)

Next came the hard part - the Hab module. It still had its radial bits with the probe cores and little rockets, so that could lift its orbit, get a rendezvous, match orbit and get nice and close. Action groups allowed easy switching between the forward and rear engines to control speed, but it wasn't exactly the most graceful of things. The tug detached, and came down with a case of "Designed by a hack with no rendezvous experience and little probe experience". Terrible to maneuver. Managed to link it onto the Hab module, then decoupled its launcher bits. It was perfectly fine where it was, so I deorbited the unbalanced, terribly planned little rockets and let them burn up in atmosphere.

Docking the Hab module itself was another problem... It was a single docking port, next to the tank, but all the thrust to bring it in was on one end with the tug, making the approach awkward at best. Eventually, I decided that if the Hab module won't come to the station, the station would have to go to the Hab. That worked out better, but it really wasn't something I wanted to have to do again, particularly with the Hab module secured by a single docking port - it'd wobble all over the place, and the station might shake itself apart, or something. Then I moved the terrible to maneuver, horribly designed, weak little tug back to one of the endpoints of the station.

Then MunTherm made it home, and I bought Electronics. Then the Seismic Minmus Mission happened, getting me lots of science, with which I got Large Control, Large Electrics and Advanced Flight Control (and Advanced Science Tech, not that that's connected with this). So, bigger, better RCS, a nice shiny new probe core, Z-1k batteries and the Gigantor arrays. Also, the Cupola module, the MK2 Lander can and the inline ASAS. So I could put a Command Module together.

I also noticed, looking at the station, that I may want a little piece of the structure to stick out a little further, in case I want to dock a spaceplane, should I ever advance those enough to achieve orbit by any more than the skin of my teeth (probably need better engines/wings. Or better design, but that's a given.) So, I put together a simple command module, and a little thing that was basically an OKTO probe core, an R10 RCS tank, two Z-200 batteries and a girder-FLT connector on each end, with docking ports. Also some RCS thrusters and a pair of Gigantors. Because, somehow, I needed even more solar panels, despite generating many, many times more electricity than I use on the station, and my habit of putting some kind of solar panel on pretty much everything. This makes sense, as does the Z-1K on the command module. Really.

The command module had an orbital maneuvering stage on the top, and its own RCS tank, some static solar panels, and it could of course dock itself with RCS. Or, rather, Kenlan Kerman could dock it using RCS. Sent them up together, with yet another overpowered rocket, this time hoping that a few separatrons would deorbit it. (They didn't. Tracking Station's Terminate took care of it though.) Docking was easy, particularly when compared to that horrible little tug, and the OKTO on the maneuvering stage could decouple and deorbit, taking the stack decoupler with it away from the Cupola, freeing Kenlan's view. Not that that was particularly great - looking down at the darkside of Kerbin.

After a little thought, trying to figure out what was missing from the station, it hit me. Crew. The Hitchhikers in the Habitation module were completely empty, and I had no real shuttle design, or any such thing for crew transference. Also, that tug really, really had to be replaced. Even if its replacement was untested, quickly obsolete, never/rarely used... it had to go. Built a little thing with an OKTO core, a Z-1k, FL-R25, Inline ASAS, RCS thrusters and of course, solar panels (Ten times the battery it will ever need? Put solar panels on anyway). Docking ports connected it to a Mk1-2 Command pod, which had an FL-R1 under it, then a large reaction wheel, a Mk2 Lander can, a Rockomax X200-8, a flat Rockomax-FLT adapter and another docking port. Four Rockomax 24-77s for maneuvering, RCS thrusters, lights to see where I'm docking, solar panels (it's not an addiction), parachutes and that's a Crewer. Fill it with new recruits - no sense risking the old hands here - stick it on an overpowered rocket (Same one as I used launching the tank, actually. Just without Bill's little bit. Because that worked out so well. If it was over powered there, it can only be more so here.) and up we go.

The Crewer docked fine, the new tug was infinitely easier to control (because it was designed by someone with infinitely more experience in the area. Me, but this time with more than no experience at all. That counts, right?) and the old tug went off to be terminated like a good little drone-thing. EVA was smooth, transferring four kerbals clear across the station to the Hab module, leaving Dozer in the Command Pod to pilot the Crewer on its return journey. I then looked at the Crewer's RCS tank, which was huge and almost full. So I did a little fuel transfer to fill all the RCS tanks on the station from the Crewer, which left it still about half full.

Below are some screenshots of Station Aleph in its "completed" form. Don't think I'll be adding to it, but hey, never know. Depends whether I decide it needs more or a completely new station should be built, when the time comes.

That third screenshot is Dozer undocking for his return flight. I put the lights on, because Station Aleph was on the night side of Kerbin at the time. Then I turned them off, because even though there're enough batteries on that thing to have all bulbs on full glare for several orbits even without all the solar panels everywhere, I wasn't docking right then, so there wasn't any point beyond a screenshot. Descent was pretty textbook - get away from the station, out of its orbit, periapsis down to thirty-something kilometers, then a retro burn once there on the day side. Use RCS if needed, slow to 150m/s, deploy chutes. What could go wrong?

That. That could go wrong. Chutes could rip the ship apart when they fully deploy, because you deployed at 3000m ASL over the highlands, and full deployment was 500m AGL - which here is about 1900m ASL. Still moving pretty fast. Very, very lucky no one was in that lander can that is not in the picture, because it smashed into the ground and exploded by the time I thought to take a screeenshot. In retrospect, perhaps those four chutes should have been on that, rather than on the RCS tank. The two chutes on the Command Pod were a good placement though, so Dozer survived. Four chutes on a little under half-empty FL-R1 slows a fall much more than two on a Mk1-2 pod, so the pod slid off and touched down first.

The tank made it safely too. So a minor redesign, shifting those four chutes to the lander can should mean that the return journey is survivable for a full Crewer - or at least, its occupants. I hope.

Anyway, Station Aleph is now in orbit, and basically complete. I think I learned a bit about docking from this, which should come in handy for the future, particularly when I decide to go interplanetary.

[Concentric]

I decided that Station Aleph needed some way to get the Kerbals back down without sending something up to get them. This will also mean that future missions do not need to be able to return to Kerbin on their own: if they rendezvous with Station Aleph, all science and Kerbals can be transferred to the return modules and safely returned to Kerbin, leaving the ship up in orbit.

The first version had far too much monopropellant - it probably accounted for over half the weight of the thing, which had landing legs, batteries, parachutes and a Mk1 lander can. Testing a single one was fine, it wasn't all that heavy alone, but five at once was suddenly something that my extremely poorly designed lifter was unable to handle. Also, I'm pretty sure it could have returned to Kerbin from Minmus orbit. So I cut it down to size, removing the Cylindrified tanks and replacing them with Roundified ones. This also gave me a little room on those two sides to put lights and move the batteries. Then I stacked five of the modules up and built a new, vastly overpowered launcher.

There it is on the pad, and here launching:

Two layers of asparagus, and I still had enough fuel to probably take these to the moon. Dropped the last two tanks when they were about 1/3 full and adjusted my inclination.

I still had a full tank, pretty much, but I didn't really need much of it to get a rendezvous, and docking wasn't hard at all (Not pictured - the former attempt, where I didn't have that big R1 and large reaction wheel, so deorbiting the last of the lifter section ended up torching the station. Reloaded from quicksave - which was in the middle of testing the current deorbiter version. Returned that hard, killed Bill - see here.)

Had a bunch of monopropellant in the R1, so I filled up the tanks of the returner modules. If I'd disabled those tanks on launch, this wouldn't have been necessary, but there you go. Afterwards, I deorbited the lifter (this time on RCS, so no torching. Still had an almost full liquid fuel tank...)

And here're a couple of pictures of the station in its current state:

Edited February 23, 2014 by Concentric

[Silverchain]

I like the big stack of lander cans, and it's a good looking station in a functional sort of way. Compact.

[Concentric]

As those who thoroughly read the "What did you do today" thread in General KSP Discussion will know, I have recently been working on making a spaceplane that docks with Station Aleph. And today, I succeeded, not once, but twice. And all without Advanced Aerodynamics and High Altitude Flight and their dependent nodes (I wanted to prove to myself that turbojets, structural wings and similar things are nonvital). This also marks the first mission in which Station Aleph has been used, as the spaceplanes needed to refuel a little before returning.

So, the first successful plane was a quick modification of one of my earliest spaceplane designs, the unimaginatively named Spaceplane0 and its descendants, Spaceplane1, Spaceplane2 and Spaceplane3. (Also similar was Probeplane, but no-one cares about Probeplane.) Keeping in theme, I named it Spaceplane4 - my other spaceplane designs had largely taken names from their design philosophies, rather than from being my first spaceplane that was in fact a spaceplane rather than just a plane. I took Spaceplane3, removed the Z-200 batteries, replaced them with circular intakes, then put on a Z-400, a docking port and two Cylindrified monopropellant tanks and called it good. Or at least, good enough to test, and to learn a few of the secrets that lay within that black magic box called "beginner's luck", which could then be applied to a new design.

So, of course, it succeeded beyond my expectations. I really didn't expect Spaceplane4 to actually get so far as to dock with Station Aleph, but there you go. Refuelling was routine, I took very little fuel from the tank - just enough, I thought, to deorbit - and took quite a bit of monopropellant, roughly half-filling the spaceplane's tanks there. Turned out I took much more monopropellant, and about half the fuel and oxidiser than the amount I needed, but landing wasn't too difficult.

Feel the burn...

---

Next came Spaceplane5, so called because of how heavily it was based on Spaceplane4. Oh, the wings were changed, the cockpit switched, the battery swapped out, the docking port moved, the intakes shifted... Okay, perhaps it wasn't based that heavily on Spaceplane4. But it had the same fueltanks with the same load, the same landing gear, same engines, same reaction wheels, and sort of the same ejection system. I did add a ROUND-8, a Roundified and an additional circular intake onto the cockpit, though.

The ascent profile was about as is normal for my spaceplanes, though it certainly took off at a lower speed than I was expecting. Probably all that extra lift... Anyway, jets on, full throttle all the way, pitch up, take off, pitch up until prograde is at about 30 degrees, then keep pitching up to keep it there until IntakeAir is at about 0.10, which should happen around 400m/s, 20km ASL. Then activate rockets, and wait until IntakeAir is roughly 0.05, or about that time you fear asymmetrical flameout due to oxygen starvation, and deactivate jets.

Cruised up to orbit, pitching down whenever time to apoapsis rose above 45 seconds until pitch was horizontal, then remained level until apoapsis height was 75km, cut throttle and waited to reach 70km ASL. Then pitched to apoapsis' prograde and began an all RCS circularisation, which went rather well, I felt.

I extended my solar panels, then set up an encounter on RCS and fired rockets to reduce relative speed and match orbits. Docking was a little awkward, but much better than with Spaceplane4.

And here are a few pictures of the spaceplane docked to the station.

A spot of refuelling - this time without taking so much monopropellant - and it was time for Bill to return to Kerbin. After clearing the station on RCS, I fired the rocket retrograde with all the fuel, which was more than enough to deorbit. Perhaps if I had fired a little less, I would have come down in a more suitable location, but I wasn't thinking, and it was on the dark side, so I decided to hope I got a good spot.

Flame On!

I didn't. Instead, my return was over the ocean, which wasn't a place I had tested landings at all. Not liking my chances, I decided to glide and hope I reached land. Unfortunately, I was coming down at the beginning of one of the longer stretches of ocean along the equator, so no luck.

That picture was from a little way into what ended up being a half-hour glide. To me it was considerably less due to the power of Physics Warp, but Bill felt every second, I'm sure. Eventually, I realised that this glide wasn't going to get me to any land, so I decided to give the water landing a shot. Of course, I neglected to notice the fact that I was still at Physics Warp x4, so I oversteered, overcorrected, stalled, and ended up plummeting out of control.

Bill was lucky I had installed that ejection system. Though I don't think that landing upside-down in the middle of an ocean that he had just spent the last half hour trying to glide over was the most dignified of returns, it was a safe one. I'm sure Bill is happy to have survived a return from Station Aleph this time (though, wasn't he piloting Spaceplane4 too? Bill, your dedication to this station is remarkable).