sevenperforce

For a specific set of details, I can tell you the near-optimal ascent profile for a desired orbit.

No. An exciton is when a single excited electron becomes bound to the valence space. Excitonium is when the bound states overall form a condensate relationship within the larger molecular matrix. Remember that total charge is conserved.

2.55 Whoa! Yeah, definitely cut those SRBs way down. And you can absolutely afford lower thrust on the core, so replacing one Vector with a Thud or two is a really good idea.

11,532 Def lower the SRB thrust a touch, if you can. What's your takeoff TWR? If you place Thuds separately, you can use an action group at staging to cut one and realign thrust.

Anything natsec is considered essential. Contractors will be furloughed but anything DoD, Homeland Sec, etc. will be at full capacity.

This is not a candidate for dark matter or black holes or anything like that. This is a condensate state where excited electrons become bound to open spaces in valences of the atoms in the surrounding lattice, rather than just bouncing around. It's another example of matter, energy, and information bleeding into each other, and is weird/counterintuitive like quantum teleportation and particle-wave duality, but it's not a novel type of matter.

I was a fed contractor -- regulatory enforcement in the energy sector -- during the last extended shutdown in 2013. My job was suspended during the shutdown because although I was necessary for ongoing litigation and safety reviews, nothing I was doing couldn't be postponed a few weeks. All long-term projects were put on hold. We stopped new-construction permitting and open cases/court dates were continued. About half of my actual fed-employee coworkers were furloughed; the other half worked in half-day shifts from home in case there was a major accident that required emergency response. Next week, I expect a lot of administrative offices to be closed. Medicare offices will run on a reduced crew...still processing existing applications, for example, but not taking new applications or processing subrogation claims.

How high was booster sep? You may need to lower SRB thrust to get a bit higher before separation. Set the fuel priority drain order on the core to drain the lower tanks before the higher ones. This will push the CoM forward as the tanks drain, aiding passive aero stability and minimizing cosine losses. And this probably goes w/o saying, but are you testing CoM/CoT alignment post-sep? By that, I mean pulling off the SRBs, draining about half the tank fuel, and ensuring good alignment, then getting launch thrust alignment fixed.

There are two main ideas here. The primary idea is that you have your long-term life support systems and extended hab space in orbit permanently. You don't save dV, but you save fuel mass because instead of accelerating a whole extended-stay space station to a high-speed transfer, you're only sending up a small shuttle. The other element is that they are Aldrin Cyclers, not just a single cycler. There are a series of orbits which swing from the Mars SOI to the Earth SOI very fast, then spend a couple of years in an eccentric solar orbit before repeating the same cycle. If you have 3 or 4 of these ships in play, then there will always be a ship approaching for an optimal rapid transit, while the rest are out in the long periods of their orbits. Those long periods are the problem, though. The cyclers will need regular resupply and maintenance; each cycler is only "used" a few times every decade, so it can't really be expected to last very long. Each shuttle ends up needing to do a full resupply, so you don't actually end up saving so much mass. The other problem is that it's not terribly safe. What if the shuttle has a problem, or fails to dock, or something like that? Will the shuttle have enough dV to abort back to where it came from? Probably not. Then the shuttle will also need extended life-support systems, which obviates the need for the cycler. If possible, I would aim for your Ike encounter on the back end of the pass, rather than the front end. If you come out of your aerocapture pass still at escape velocity but get a retrograde Ike swingby, it will likely be able to bend your trajectory into a high Duna orbit. From there it will only take a tiny burn to make the next pass take you back through Ike's SOI to bend you back into Duna's atmosphere for your subsequent easier braking passes. If you have decent passive aerodynamic stability it shouldn't be a problem.

Try mounting the SRBs using Mirror Attach and then translate them both toward the shuttle, so their thrust vector is lifting through the decoupler. To save costs, replace the two Vectors with just one, then add a few Thuds, tied to an action group. The Thuds have a great gimbal range and can be angled a little off-prograde to help maintain a good thrust vector prior to SRB separation. Angle the vector so that when you cut the Thuds, it is going up through the CoM of the stack when the main fuel tank is about half empty.

Just for kicks, here are those homemade landing legs:

Just for fun, here's the rest of the mission. Back to the upper stage. Our (convenient) loiter is complete, so let's kick on the engine for the transfer burn. And SECO-2 in a good orbit! Payload release. The first time I flew this mission, I was an idiot and actually forgot to put a probe core on the payload. At least this time I remembered. Also remembered to get those solar arrays out before my probe core dies. Now to deorbit the upper stage. A little radial burn changes the argument of periapsis and lowers it to a good disposal orbit. I totally guesstimated the amount of propellant I'd need for circularization, but I figure three donuts should be plenty. The Ant is efficient enough after all. Setting up the circularization node for the relaysat to see when I need to start burning. Throttleup to begin slow circularization. Of course this is probably far higher acceleration than what real-life GEO comsats do. Getting there... And there we go! Tiny inclination correction burn. Setting thrust limiter way down to refine my orbit. Pretty soon... And that's a wrap! The payload was just for kicks, of course; the primary mission was designing and deploying fancy landing legs that would work the way I wanted. With a crane and a custom leg-lifting rover, I believe I would be able to refold the legs and refly, though of course the design would need the upper decoupler replaced with a docking port in order to add another upper stage and payload. But as these things go, it seemed to work pretty well! I will have to remember this design if I ever want to develop a really robust reusable launch system. I've sometimes thought about playing a hard mode career game, and having a reusable launch system with virtually unbreakable legs would enable me to launch payload after payload without ever having to build/recover first stages.

I played around with different hinge designs, specifically to try and get it down to just four hinge assemblies, each holding the corner of a leg (like SpaceX's), but was unsuccessful. Hinges are not my strong suit. Got a better idea? To be fair, my boostback burns are nowhere near as precise as I would like them to be. I had to fly it a half-dozen times to get the boostback right. Landing was a good bit easier, though; I quicksaved once I had a good EDL trajectory, but I didn't end up needing to quickload. I've had a lot of practice with suicide burns. Here's the craft file, though it'll only be up for a couple of months: https://files.fm/u/xepzwm6e

Ever get tired of stock's shoddy landing legs that don't work as advertised? Solution: build your own. Easier said than done. It is easy enough to build a set of legs, but not ones that start folded and then deploy at landing. But I managed! Here it is on the pad. Planning on using an expendable upper stage and sending a relaysat to KTO, but bringing the first stage back with RTLS, SpaceX-style. Detail view of the landing legs on the pad: The legs start folded, held against the side by paired docking ports. I could have done it with decouplers, but I wanted them to be refoldable, at least in theory. The leg itself has a crossbar which is suspended between paired structures coming out of the rocket body to form dual hinges. On the pad, the rocket is held up by double-docking-port clamps, which are themselves held to the pad with launch clamps which will not be used. When the rocket launches, the lower docking ports release by action group. These same docking ports become the locking mechanism for the landing legs later on. I went with five engines because I wanted to do it pure-stock; otherwise I would have tweakscaled down the Vectors and done it with nine engines, just for kicks. Ignition: And clamp release! Very thrusty off the pad, but that's what five vectors will do. Throttling down around Max-Q, mostly to help loft my trajectory a bit. The higher and slower I stage, the better shot I have at getting the boostback burn just right. I turned off fuel flow for the bottom tank, so I don't have to worry about how much fuel I am reserving. Down to fumes, so I cut the outer four engines and throttle the single engine back up in preparation for staging: Staging! Switch view to orbit to point more downrange, then back to the booster for the boostback burn. This is a rapid sequence of events. Set SAS to Orbit-Radial-Out to begin the RCS flip, activated the airbrakes, mashed X to cut throttle, and turned the lower tank fuel flow back on. Single engine back on and burning hard. Switched the navball back to surface so I can see when my surface prograde marker noses back over toward the west: Money shot of the boostback burn, with detail of the lower landing leg locking clamps: The prograde marker is now over on the west side of the navball, so this should be enough for a boostback. Cutting the engines and heading back to the second stage. The second stage has just cleared the atmosphere, so I'm blowing the fairing and nosing down. Burning halfway between Radial-In and Prograde in order to push to orbit as quickly as possible. Throttling down and following the prograde marker would be more efficient, 'tis true, but it's time-consuming and I don't have much time. You can see the first stage is still climbing: Almost to orbit... Made it! Throttled down and switching back to my first stage. Quickly set surface orientation and retrograde. The airbrakes form a nice little landing crosshair. I should come down just off the coast. I won't need an entry burn. Here come the gees! Punching the engine to full throttle just after the accelerometer shows terminal velocity. In pad testing, I used separatrons to force the legs down to snap into place. I thought I might have to do the same, but it turns out that the upward thrust of the landing engine results in enough differential force to pop the legs out, once they are released. I set the docking port release to the Gear action group, just to make it more authentic. Just about to throttle down... The legs cannot be released at a high airspeed, or the airflow holds them up no matter how hard I thrust. Which works well, because I need to drop the gear pretty close to the ground anyway. Gear dropped! At this point, all four separate landing legs are viewed by the game engine as debris. So they are falling separately from the stage. However, the hinge keeps them stuck to the stage, and the gees on the stage itself from the engine lifts it up, causing them to rotate down: Oddly, there's always one leg that rotates slower than the others, but it's never the same one. I guess that makes sense, because they are all separate parts. Punching Z again to make sure I get a good inertial lock on the legs. As soon as the ports touch, it is viewed as a docking event and the game switches views and turns off my engine. So this was a lot of constant Z-mashing. Then I quickly switched SAS to Radial-Out and throttled down to avoid air-launching. I think I kept my TWR above 1:1 the entire way down. A bit of a bounce, Bulgariasat-Style: But I recovered! There she is, standing tall and not at all wobbly. Detail view of the leg locking assembly. And done!

Truly magnifique!!

If you afterburn a certain amount of LOX along with your primary fuel in a nuclear thermal rocket engine, your average isp will be lower than if you burned only your primary fuel, but your net dV will be greater than if you merely dumped the LOX separately. If you inject water into nuclear thermal rocket engine exhaust your net dV will be identical to what it would be if you dumped the water separately. However, your thrust will be higher during the H2O injection.

Yeah, a LANTR would be really nice. I would like to see a 2.5-meter LANTR with "wet" and "dry" modes, plus the ability to run only the alternator (since it is, after all, a nuclear reactor), albeit with the need for cooling radiators. The "dry" vacuum TWR wouldn't be as good as the LV-N, but the "wet" TWR would be nearly as high as bipropellant engines, both in-atmosphere and out (albeit at a lower isp....like 500s or so). Then you could use the alternator to power ion engines when you're far from Kerbol. If they introduced "active cooling" tiles, they'd have to be procedural to a degree. You'd lay one down, and then connect other tiles to it, and once you launch, the connected tiles all merge into a single part with a single set of tweakables. Yes, LOX-afterburning in nuclear thermal rockets boosts thrust dramatically but hurts specific impulse. In the real-world, it would be trivial to build an SSTO with lox-afterburning nuclear thermal rocket engines, if it weren't for all the pesky people complaining about dumping nuclear waste into the atmosphere.

How about an "active cooling" tile? Functions like an ablative heat shield, but instead of consuming ablator it consumes other resources from your ship, and you can surface attach it to heat-shield other parts. I'm tired of being stuck with circular heat shields and no heat-resistant structural parts. Like the Convert-O-Trons, it would have toggles to select which resource to use. Different resources would have different heat-sink capabilities. It would have an activate/deactive toggle and a "dump rate" slider at the top, which allows you to choose how rapidly to dump your selected resource (from 0 to 100), and a toggle to choose whether dumping is done manually or automatically. Then you could use it to dump non-essential resources, or you could use it to build a regenerative heat shield.

I usually set up a rover probe core using something like the RoveMax so that "control from here" points me radial, and then I set "hold radial out" on SAS and set the reaction wheels to SAS only. Can do it with other probe cores, or with a command seat probe core, using a vertically-oriented docking port. Doesn't hold me exactly parallel to the ground, but it holds me parallel to the sky, which is close enough.

I think refueling is fine, since there are definitely some inventive things that could be done with it, but I think we should say you need to send it all up in a single launch at no more than 1000 tonnes (or, at the very least, put a hard limit on the number of launches, like 2 or 3). I could also significantly increase my dV out of Kerbin SOI by using a drop-tank spaceplane for the launch. That quick-and-dirty asparagus rocket got about 200 tonnes to LKO, or around 20% of launch mass, but I could easily get over 40% of launch mass to orbit if I used horizontal takeoff and Rapiers. It would be interesting to see what would happen if someone were to do ISRU at Eeloo. Potentially much higher dV, but time spent getting to Eeloo and doing ISRU is time you're not spending on your coast out of Kerbol SOI. Might be wiser to refuel at Minmus, if one were to go that route; you can get there quickly, you don't spend much dV getting off, and you have a good bit of solar power for the ISRU project so that's less mass to worry about.

Wait, weight per vehicle launch is 1000 tonnes? So I can launch, like, fifty ginormous drop-tank spaceplanes, dock them all together, and asparagus-stage the hell out of them? This could become...prodigious.

Here's an LFO-only, direct ascent entry with a launch mass under 1000 tonnes. 2.4e11 meters. Will be hard to beat without gravity assists, nukes, or ions.

Not necessarily the case. I don't mind doing a 4x timewarp and leaving it to blow through a bunch of LF or xenon. A launch mass limit would be a good idea, but it would be somewhat arbitrary. Guess that's not necessarily a problem. The easy limitation would be to have it done in the career version, but it's a substantial investment of time and puts people who usually play sandbox at a disadvantage.

My concern is that this would definitely end up going to whoever's PC is biggest. So are nukes and ions out or not?

Yeah, that's my experience in testing. There's no roll authority at all; those winglets are bound to go shuttlecock. Thrusters are good for initiating pitch, roll, and yaw movements, but I don't think they can be relied upon to continuously fire to oppose aerodynamic forces. I tried modeling a BFR with more lift in the front, by adding some wing strakes up near the nose, and it gave me a pretty balanced entry and descent but its stall speed was so high that it went into a stall and tailspin at the very beginning of the landing approach.