sevenperforce

I doubt it. The Falcon 1 used a gimballed preburner exhaust nozzle for roll control on its single first-stage engine, but per the Falcon 9 User's Guide, second-stage roll control is provided only by cold-gas thrusters. The Merlin 1D Vacuum vents preburner exhaust into the nozzle extension for extra thrust and specific impulse (this takes advantage of the fact that the static pressure in the nozzle is very low even though the axial dynamic pressure is rather high).

Short answer: no. Longer answer: also no. Airbreathing turbine engines are very heavy, so they do not have a high enough thrust-to-weight to take off vertically, not with any appreciable payload. Thus, they need to take off horizontally, which means you're back to air-launch. The thrust-to-weight ratio of a ramjet is a bit better, but then you have to deal with getting up to speed first, which probably means separate rocket engines. And even then your useful envelope is low, and you're accelerating more and more slowly as you climb, when you want to be accelerating faster and faster. Airbreathing engines are good at efficient cruise, bad at continuous acceleration.

It's easy. Collect a lot of hydrogen. Like, a lot. No, you're going to need a lot more than that. Let it condense into a sphere. Wait until its self-gravitation ignites fusion in its core. Wait for the fusion to grow most of the elements you want. Wait for the death of fusion to result in a core-collapse supernova, creating the rest of the elements you want. Send Von Neumann probes around to collect raw materials from the supernova remnant. Wait, what were you saying about Mars?

The other reason to have excess hydrogen in the exhaust is to incorporate unburned propellant, thus providing a heat sink to control the reaction temperature. Even a regeneratively cooled combustion chamber will melt to slag in any extended burn if its reactants are pure-stoichiometric. With other propellant combinations, you can run ox-rich for the same effect if running fuel-rich would result in coking. Of course then you're dealing with hot oxygen, which is kind of like using cocaine to wean someone off of caffeine, but oh well. It should also be noted that changing your mixture ratio during flight can be very beneficial. You can start oxygen-rich for extra thrust and then transition to fuel-rich for better specific impulse as your need for thrust decreases.

Well, in the original one he had the caveat that kerbal cabins had much higher effective kerbal capacity, so that wasn't really a problem. Other possibilities include cargo capacity combined with passenger capacity, seaplane capacity, stuff like that.

Just go ahead and reboot it. He said it was open for someone else to reboot. But you should add some new requirements. Not so much to make it onerous, but perhaps a few other things to optimize for. For example, you could make the cost be dry cost, not fueled cost. You could class by cost rather by range, speed, or crew capacity. You could include supersonic options or wider-ranging executive/express jets.

All right -- here are my entries for Falcon 5R and Falcon Air! Falcon 5R: Falcon Air:

EM-6 addendum (forgot to bring the crew home):

@Bottle Rocketeer 500 Can you clue me in on later missions so I have an idea about what to include with logistics? Are the Kerbonauts going to be doing a Mars flyby? An Ike landing? Are they going straight to the Big Landing? I can send up some cubesats or relays or even an Ike ISRU rig; it all depends on what the mission sequence looks like.

Kerbals have unlocked the secret to the Infinity Torch -- a special module which taps energy from an alternate dimension and allows any engine to perform at 100% thrust with no propellant at all. (This module can be enabled by selecting Alt+F12 and checking "Infinite Fuel"). With this came the rise of torchships -- vehicles capable of performing Brachistochrone trajectories, accelerating constantly from Kerbin's SOI toward their destination and then turning around and accelerating in the opposite direction until they arrive. Space travel has grown exponentially, and it's time for you to make your entry into the interplanetary transport market. The challenge: Build an Executive Torchship transport suitable for Brachistochrone transfers. Fastest possible round-trip time wins. Rules: SSTO, obviously. No need to stage when the rocket equation is broken. Your vehicle must not take damage at any point during the mission. All stock. You need to be able to take off and land in style, on any surface, so it must have separate VTOL landing engines. You need crossrange capability, so your craft must be aerodynamic enough to fly to your landing site using aerodynamic control surfaces before engaging its VTOL engines. This also will allow for a survivable crash-landing if you suffer engine failure. Torch drives can be finicky, so you need to carry at least enough propellant to make your final landing without Infinite Fuel turned on, just in case. Kerbin doesn't yet have inertial dampening technology, so for your executive passengers' comfort you must keep your total gees below 8 at all times. You must carry at least four passengers and at least one pilot; command seats are not allowed. Round-trip mission time is any amount of time during which the vehicle is moving. So you can land at your destination and wait as long as you want for an opportune launch window; it won't count against your mission time. Entry levels (will have separate leaderboards): Torchship Jockey. Take off from Kerbin, land on both the Mun and Minmus, and return to any place on Kerbin (no splashdowns). Torchship Navigator. Take off from Kerbin, land on Duna, and return to Kerbin within sight of the KSC. Torchship Pilot. Take off from Kerbin, land on Eve, and return to a landing on the runway at KSC. Torchship Commander. Take off from Kerbin, land on Laythe, and return to a landing on the helipad on top of the VAB. Torchship Master. Use your torchship for a Grand Tour, landing on every body in KSP other than Jool. I'll put together some cool badges once we have entries and can award them. Good luck!

It's a RTLS, though, so it all balances out.

Already factored that in. At the equator the ground's speed is 464 m/s due east; at 28 degrees N latitude (Cape Canaveral) it is 409 m/s due east.

Speed shown in the stream start relative to the ground, but the speed tracking algorithm changes to orbital speed gradually during ascent, because there is a smooth transition from zero to orbital speeds. This can be seen in cases where the speed of stage 2 is tracked; the final velocity is correct for the orbit rather than being reduced by 409 m/s.

Comms? Instruments? Gotta be more specific.

@Bottle Rocketeer 500 What does the EM-7 Logistics Module entail? Is it just a refueling mission? Something that docks onto the DST?

Eh, I seriously doubt anyone would worry that the US Government is secretly disguising its nukes as rockets. Anything substantially heavier than iron is only formed in trace amounts during core-collapse supernovae or, very rarely, in neutron-star collisions.

In all honesty, they should vary the mass ratio and volumetric ratios of the tanks at each diameter. Mk3-sized tanks are probably hydrolox, so they should have poor volumetric ratio and good mass ratio. Mk2-sized tanks are probably methalox, so they should have medium volumetric ratio and medium mass ratio. Mk1-sized tanks are probably kerolox, so they should great volumetric ratio and poor mass ratio. The smallest tanks are probably hypergolic and should have absolutely fantastic volumetric ratio and really really poor mass ratio. It's more realistic but doesn't require anything extra from players.

Since I use the Oscar-B and Round-8 fuel tanks primarily for small probes, landers, and service modules, my head-canon says they are probably hypergolics, which have a high density.

At T+2:28, MECO, altitude is 61.1 km. At T+2:32, staging, altitude is 65.2 km. Thus, the average vertical component of velocity is 1.025 km/s. Since staging velocity is about 1.63 km/s, this means the horizontal component of velocity is roughly 1.27 km/s. However, Cape Canaveral is comoving underneath at a nice steady clip of 409 m/s, meaning that the Falcon 9 first stage only needs to kill about 860 m/s of downrange velocity to essentially "stop". In certain cases, there may be a need for both boosters to land on an ASDS. In such cases, the core will be going so fast that it will almost certainly be expended. So they will probably need one more ASDS for the Atlantic. I don't anticipate another one for the Pacific.

Distilled water is just fine to drink, though in the long run it can deplete the minerals in your body. Deionized water, on the other hand, is much less safe. In small quantities it is fine, but if you drink enough of it, you can end up dehydrating yourself because the semimpermeable membranes in your cells will leak water in an attempt to equalize the ionic balance.

I want to know this too. I also want to know if we can use reverse thrust.

Nice! By the way, here's EM-6.

All right, we've made it to EM-6. Time to design the Deep Space Transport, a hab and propulsion module to take Kerbonauts beyond the Kerbin SOI and into interplanetary space! It's a little longer than I wanted, but as you can see, it's got six cupolas, a mobile processing lab, and a 4-kerbal can, for a total of 12 seats. Two spare docking ports in addition to the one on the nose. The propulsion module is beefy, with a fair bit of bipropellant, a tweakscaled-up xenon tank, and a large monoprop tank. More radiators, both fixed and deployable, and two very very long solar array arms. I'll get to those later. As you can see, fuel loading is low, both to comply with challenge requirements and because the SLS Block 1B couldn't throw a full one all the way to cismunar space anyway. The fairing is much longer than I'd like, but oh well. Nice clean booster separation. Burning for orbit. Core burnout with a disposal periapsis. Fairing jettison. Like I said, this was too long for my tastes, but there's really no way to make it much more compact than this. EUS ignition to circularize. Circularized! Now came the fun bit. Remember those long solar arrays? They each contain probe cores, reaction wheels, and RCS tanks+blocks...so all I had to do was decouple them and then recouple them. Easy, right? First one done! Second one swung a bit far out... Steady as she goes... There we are! Solar arrays deployed! A beautiful sight. Turned on the radiators, because why not? Trans-munar injection burn, started. Firing up the EUS again. Full throttle. Had to autostrut the solar arrays to keep them from bending over like twigs. Halfway through the burn. Really cut it close with my periapsis, though I suppose that's good for Old Oberth. Finishing it out. Not bad! And a disposal orbit for the EUS to boot. Separation. Engines fired up. Burning all engines for capture. Nice shot. Plotting how I'm gonna catch up with the DSG. Shutting down the main engines. Intercept maneuver near apoapse on ions alone. This solar array is fantastic. Inclination canceled, primary intercept set up. Time to match velocities and complete the rendezvous. Doing all this on ions. Approach... Nearly there! Aaaand now the Deep Space Transport (albeit not-very-fueled) is docked to the Deep Space Gateway with Orion attached. Where do we go from here?

But still, divide by 3.6. There are 3600 seconds in an hour and 1000 meters in a km, so there are 3.6 km/hr in a single m/s.

Very, very low. Earth has a high proportion of heavy elements because we got smashed into by Theia and we have a very high amount of geothermal activity, forcing heavy elements up into the crust. There wouldn't be enough in asteroids to mine.