Starman4308

My guess is because you really don't want an expensive and fragile rocket stage on top of an expensive and not terribly stable barge in the middle of the Atlantic Ocean very long. All it takes is one sudden storm to wreck your booster, your droneship, or both.

When it comes to that offered slot, as with most ridiculous things, I suspect there's something going on I don't know about that makes it non-ridiculous. Anyways, while SpaceX is being held to a higher standard than ULA and the SLS, I don't think it's necessarily an outrageous standard. For all that I groan about continued complaints about the COPVs, I try to remember that many people at NASA were groaning about continued complaints about the SRB field joints... until they failed, and took seven astronauts with them. The ULA standard is debatable. I'd like to see a few more 2-engine Centaur tests, but otherwise the Atlas V-Centaur combination has an almost ridiculous reliability record. The SLS standard is absurd, but I suspect NASA is under political pressure to continue wasting their money on the rocket the Senate designed for them to waste money on. The only real bright side is it probably won't fly enough times to kill astronauts.

"Kraken drive" is a nickname for types of propulsion which rely on glitches or exploits in the code, at least some of which have been fixed. For example, a Kerbal climbing up a ladder into something overhead would produce an upwards force in defiance of the laws of physics, permitting any speed you want so long as you are patient enough.

When it comes to how things are in the code, I believe KSP uses the same universal gravitational constant G as the real universe: it's that the planets really are ridiculously dense. Granted, you could handwave it as a difference in units used, that a "kilogram" in KSP isn't a real-world kilogram. Of course, then you have to explain the density of rocket parts (though some things like liquid fuel and oxidizer are way too dense to have any real-world analogue, so...).

Please note that there is far more for KSP to handle than "thrust and torque". The ships aren't treated as one big piece: it's often hundreds of parts, each with their own masses, aerodynamics, and temperature, connected together with rigid linkages. An engine fired on one end of the craft winds up transmitting force all the way through the rocket to the capsule at the top, and it winds up being a monstrous O(N^2) problem to solve all that self-consistently. No comment on the garbage collection, though you might try looking into MemGraph. Admittedly, if you threw a ridiculous amount of programmer time at the problem, you could move KSP to a language with manual memory management... But not before that manual memory management caused 57,328 bugs to catch.

All of that is, frankly, a trivial O(N) problem with some glitzy graphics thrown on top. The CPU load, like most FPS games, is trivial: it's all the shiny effects that slow you down because of all the scene rendering the GPU has to do. On the server side: Each physics frame, a bullet can ask "in any of the grid cubes I passed through, do any objects have colliders? If so, did I hit them?". This is constant-time per bullet, since it only has to poll nearby objects, and O(N) in the number of bullets. Stuff like bullet drop is almost hilariously simplistic mathematics; unless you're trying for aircraft-simulator levels of aerodynamics, it's a few single-operation multiplies and adds, with nary a single exponential or division to handle. A player/vehicle object needs to respond to any player or environment inputs, but the number of those is small: maybe a few keystrokes from the player, plus mouse input, plus possibly a bullet or explosion. On the client side: The client needs to update the status of nearby objects based on a message packet from the server, respond to player input and send it to the server, and render sounds and graphics. The client does not even need to be informed of the status of every object, just nearby ones. I can't think of anything that, by necessity, absolutely has to be done in more than O(N) time... and N is pretty small, maybe a couple hundred tops. If you double the number of objects, the workload per frame just doubles. KSP's rigid body physics is not an O(N) problem. I suspect it's an O(N^2) problem, where every single part must act on every other part for consistent rigid-body physics that don't break Newton's laws into a million little pieces. This means that if you double the number of parts, the workload per frame quadruples. This is why KSP can be so slow with large part counts: the amount of CPU effort needed is going up far faster than the number of parts on the vessel.

The issue with KSP is lego-style construction with rigid body physics. 500 separate objects flying through the air would be trivial to solve. 500 objects linked by rigid body physics requires a self consistent solution that satisfies all linkage constraints without violating basic physics. I'm still unsure if it's O(n*ln(n)) or O(n^2), but the problem gets harder fast. Unity's rigid body physics solver is almost certainly not the fastest in the world, but it's being stretched far beyond what most games ask of it.

There's no way to do it in stock without the debug menu or some weird Kraken drive. Taking the PB-ION engine's 4200 s-1 Isp as reference, you would need a mass ratio of 1.5*10^3162 to reach the speed of light. Most mods aren't going to be able to do it either. To do it on a mass ratio of 1000:1, you would need a specific impulse of 4,427,058 s-1 of specific impulse. This would entail an exhaust velocity of 0.145c.

For reference, this is the Retro Solar Rescue thread: While you can definitely brute-force it with ions and nukes, if time permits, you might also try a Jool slingshot/Oberth maneuver to flip your orbit.

Jet fuel is made to a less exacting specification than RP-1. While theoretically RP-1 can be refined from any oil well, in practice there's only a few suppliers, who start from very high-quality crude oil. While it's not impossible to make a biofuel replacement for RP-1, it would almost certainly be harder to do.

You asked about the Falcon 9, not the Falcon Heavy. Also, the New Glenn still has the advantage for lower orbits, since SpaceX are still using the same payload adapter, limited to 10 tons. All FH does is make it easier to recover boosters after sending heavy payloads to GTO.

Heavier payload capacity. Vastly larger 7m-wide payload fairing. Optional third hydrolox stage for very high-energy ejections: this is useful for things like sending probes out to other planets. Methalox BE-4 engine is likely to be more easily reused than the kerolox Merlin engine; methane is less prone to coking. No hard dependence on a non-renewable resource such as kerosene: it is not hard to synthesize methane once natural gas stocks run out. Easier to ensure fuel purity and quality: kerosene is a very complicated mixture, while methane is a neat substance.

Yes: Goddard fell prey to the pendulum fallacy. Aerodynamics do not actually work that way, unfortunately, or it would've been an elegant design. The key issue is that the engines are falling at the same rate as the rest of the rocket. Scott Manley on the subject: https://www.youtube.com/watch?v=Tx4cjP-GRAY Anyways, on my end, just unlocked early hydrolox engines, and I'm playing with various Centaur-like upper stage designs. I toyed with Vulcan-style reusability, but that drives up cost of a 2-engine Centaur by 45%, mass by 5%, and reduces dV by 7%. Fuel lines are expensive in RP-0, and that's the only way to bypass the heat shield. Given that a lot of these Centaur uppers will be used to eject well past LEO, I decided to just go with an expendable design.

Relative profit is high. Absolute profit is low. Let's say you can get 5000f for suborbital missions that cost 1000f and 10 minutes, or orbital missions for 50000 funds that cost 30000f and 20 minutes. In an hour of gameplay, you can make 24000f, barely more than a single orbital mission. What's limiting and needs to be most heavily optimized for is player time, something that favors absolute profit and low time to completion.

So, what I've done today: I gave up on removing "superfluous" Baby Sergeant stages from my NK-9 based sounding rocket. Sure, I don't need the delta-V... but I do need the mass up there to keep the thing aerodynamically stable. On the unmanned end of things: this is now my second failure to get a radar mapping satellite to the Moon. The contract deadline is generous, but the financial people are getting upset. The first time was a bog-standard rocket failure on a Soyuz-Agena 1. The second launch used the new Soyuz-Agena 1.1, the sole difference being that I'm using the 8D75K versions of the RD-107 and RD-108 engines, which have better performance and reliability... though I'd shell out the extra 100f/engine gladly just for the reliability improvements. The issue this time was an antenna malfunction that left the probe out of contact when it reached the Moon. An attempt was made to set up a kOS script to handle everything, but it failed for an utterly inexplicable reason. The nature of the antenna malfunction? This, we do not speak of. I forgot to add a long-range antenna in the first place. Mariners IV and V conducted flybys of their targets: Mars and Venus. An interesting peculiarity: Mariner IV left its magnetometer offline during much of the approach to conserve electricity, whereas Mariner V, closer to the Sun, did not. Mariner V's night-side transit of Venus happened to leave it in such an orbit that, by expending about half the remaining hydrazine propellant, it could arrange a second flyby of Venus, which will occur in about a year. On the crewed end of things, I am happy to report that there is a crewed end of things. Mercury 7* orbited Earth three times with Natalya Tseydlerina onboard, and Mercury 8, with Yana Gagarina** onboard, launched from Vandenburg into a polar orbit that lasted almost 18 hours. Both are in absolutely perfect conditions from perfectly safe 13G MECO of the Agena E booster and 9G reentries, and are not in the hospital. *After the failed pad abort test, the successful pad abort test, the in-flight abort test, the totally-planned in-flight full-stack abort test, the unmanned test, and the test with Cheese the Space Monkey onboard. **The resemblance to Yuri Gagarin has not escaped me, but Yana was a scientist and I wanted a pilot on the first flight just in case. Yana Gagarina even conducted a short EVA: data from this EVA will be used to scream at design bureaus until they make a better space suit enable more ambitious EVAs in the future that consist of more than clinging to the hatch. At least one more Block 1 Mercury spacecraft is on order, with the goal of rendezvous with an Agena target vehicle. This Agena vehicle will be a modified Agena-A upper stage, with solar panels, more antennae, and helium cold-gas thrusters instead of nitrous oxide thrusters so that RCS exhaust does not damage the Mercury vehicle. After this, however, the Mercury design may either be extended for more ambitious goals, or replaced by a "Gemini" proposal for a 2-seat, more advanced vehicle.

If that's accurate: 2 hours, 44 minutes, and 54 seconds to more precision than is really warranted.

I don't think the initial throttle-back had anything to do with drag losses, and had everything to do with avoiding Rapid Unplanned Disassembly events. Even Realism Overhaul doesn't really get structural concerns quite right, but Max Q puts a lot of strain on the structure.

Clarification: New Horizons did use a slingshot, but if they missed their launch window, they could have made a later, direct window that would've taken a few more years to get there. In terms of capabilities, though, the Atlas 551 is known to be able to do a direct Pluto transfer, and there's no reason to think FH can't do the same.

At perigee, almost certainly, thanks to Good Sir Oberth. I'm halfway tempted to change my avatar for that, but I am not, sadly, the Starman.

I have only one complaint: I had to be at work. Even knowing it succeeded, though, watching the launch was a heck of an experience, the very first thing I did when I got home. I'm not super surprised. New Horizons, after all, was capable of going direct to Pluto with no Jovian gravity assist: the only catch was that New Horizons had to be very, very, very light. While Falcon Heavy has the disadvantage of running a low-energy kerolox upper instead of the high-specific-impulse hydrolox upper of the Atlas 551 used for New Horizons, it has the advantage of being much, much larger than the Atlas V.

To be fair, ULA has made good progress on the Vulcan booster, whose engines should be reusable. I'm still a bit resentful of the monopoly they had before SpaceX, but it's made substantial progress away from being a paper tiger. Anyways, kudos to @KSK for summing up my opinion on BFR: hardly a guaranteed success, and it won't be man rated for a while, but huge if it works the way Musk wants.

You might look into the steering manager to tune the "cooked" control. https://ksp-kos.github.io/KOS/structures/misc/steeringmanager.html If I understand the explanations correctly, the easiest thing to do would be to increase PITCHTS, ROLLTS, and YAWTS, making it essentially lazier about applying corrections. I've yet to test it out myself: I looked it up yesterday after my Mercury capsule burned through every last drop of HTP overcorrecting on descent. EDIT: My guess is that the default kOS PID for steering is tuned to stock, where most people use magic torque machines to maintain heading, not RP-0 where 99% of the time, there's not a single solitary reaction wheel onboard.

I don't; it'd be awfully hard to explain to my boss. Anyways, I wonder how many Falcon Heavy cores SpaceX will try to stock up on. I'm under the impression they're so heavily modified from the original F9 design that they're effectively non-interchangeable, so they'd need custom cores, for a rocket whose mission (reusable GTO launches) has been partially usurped by the improved Falcon 9, and which they're trying to make obsolete with the BFR. I'm still heavily skeptical about the BFR: even if it technically works, there's still a gulf between "gets to space" and "gets to space so frequently, with so little post-flight turnaround costs, with such high reliability that it obsoletes rockets with 1/10 its payload".

On B: I would consult in the Interstellar mod's thread. On A, they are very different parameters. As @MaxwellsDemon said, loosely speaking, you can consider specific impulse as the "efficiency" of an engine. One of the most fundamental concepts in rocket science: to go further, you need more fuel, then you need more fuel to carry that more fuel. The mathematical expression of this comes out in Tsiolkovsky's rocket equation: dV = Ve * ln(mw/md) = Gm * Isp * ln(mw/md). dV is delta-V, or your craft's capacity to change its speed. Ve is exhaust velocity. This is equal to Gm * Isp. Gm is Earth's surface gravitational acceleration, about 9.81 m/sec^2. Isp is specific impulse. Why we list specific impulse instead of exhaust velocity largely comes down to historical reasons. ln is just the natural logarithm operator. mw is the stage's "wet" mass. This includes not just the stage, but also any payload. md is stage's "dry" mass, once it has been depleted of fuel. In short, to increase a stage's delta-V, you can either improve specific impulse, or add more fuel. Specific impulse is dictated by the engine. Adding more fuel helps... up to a limit. First off, fuel tanks are not massless. In KSP, fuel tank wet/dry ratios are about 9:1 IIRC. That means the cap on your ln(mw/md) term per stage would be ln(9/1) = 2.197, and that's if your ship is nothing but fuel tanks. Second, thrust. A ship that is all fuel tanks has no engine to propel itself. To get a rocket off Kerbin, you need a TWR (Thrust to Weight Ratio) of > 1.0, preferably around 1.4. Even in space, if your TWR is 0.01, you will get awfully bored maneuvering. This brings us to Newton's Second Law of Motion: an object at rest tends to stay at rest unless acted upon by an external force. The mathematical expression becomes F = ma; force (in Newtons) is equal to mass (in kilograms) times acceleration (in m/sec^2). For rocketry, it is convenient to rearrange this to a = F/m; acceleration is force divided by mass. Gravitational acceleration at Kerbin's/Earth's surface is about 9.81 m/sec^2. Thus, to reach a target of 1.4 TWR, your rocket must accelerate at 1.4 * 9.81 m/sec^2 = 13.734 m/sec^2. This means that at launch, for every kilogram of rocket, you need 13.734 N of thrust. Since masses in KSP are measured in tons (1000 kg), and thrusts in kilonewtons (1000 N), you would thus need 13.734 kN of thrust per ton of rocket. Convenient how SI units work, eh? This, generally speaking, leads to the following design choices in rockets. For launch vehicles, you often choose engines which produce a lot of thrust per kilogram, and which don't lose too much specific impulse at sea level. Having a very high sea-level Isp isn't too important: the bigger factor is just reducing the number of expensive first-stage engines onboard while still reaching ~1.4 TWR at launch. For orbital maneuvers, you often choose engines with a high specific impulse, so as to efficiently use your fuel, and reduce the overall mass, so the rest of your rocket can be lighter. Thrust is often not hugely important unless landing on a moon/planet; I've worked with as low as 0.07 Kerbin TWR.

Technical point of order: that would be atmospheric entry, not re-entry. I mean, unless the lander has been to Mars before. Otherwise, beautiful little craft. On my end, real progress has been made on the Mercury programme. After identifying and fixing key flaws from the first pad abort test, we have completed: Another pad abort and launch abort test. A second full-stack launch abort test that was always intended as a launch abort test: the loss of performance in the E1 engine was definitely planned from the start. The full up unmanned test has been largely positive. Key flaws identified: lack of any prograde/retrograde translational authority, a defect in the reentry program that failed to turn on RCS (thankfully the spacecraft is dynamically stable!), and a need for mission planning to select a landing site that is not the side of a mountain in Papau New Guinea. Four mass demonstrator missions have been completed on my new Agena series of rockets, all of which share a common upper-stage engine, the XLR81-BA-13, with 15 restarts, storable propellants, 291 s-1 of Isp, and no ullage requirement. The lightest, the 32.3 ton Agena-A, uses an NK-9 first stage and brings 500 kg to LEO; this rocket took two attempts due to first-stage failure. To avoid contaminating the Atlantic Ocean with the second-stage hypergolic propellants, mission control pitched the first rocket up to 60 degrees. The Agena B lofts about 950 kg to LEO on an H-1 engine, and was launched out of Vandenburg to clear up KSC VAB production lines. The heaviest of this new series, the Agena E, was selected for the Mercury program, running an E-1 engine, lifts 2.1 tons to LEO, and stretches the Agena upper stage to its outermost limit. The Agena B was since used to loft a radar mapping satellite to LEO. There is also now a tundra-orbit satellite renamed "Tenacity". After a loss-of-performance in the core RD-108, halving its thrust and specific impulse, the communication relay nevertheless reached a tundra orbit, albeit a more elliptical one than intended. Mariner III was launched towards Mars. Mariner IV was launched towards Mars. Intercept is expected in about 113 days.