Shpaget

1U cubesat!* *May violate mass guidelines. Four years to build the big yeeter? Good luck, I suppose.

Oh, I parsed "text" as "sequence of written letters as opposed to voice", and not "SMS". In that case, apparently you can send SMS through email: https://www.digitaltrends.com/mobile/how-to-send-a-text-from-your-email-account/ So the above would still do the job, it would only be a matter of inputting their phone numbers instead of email address. I'm not in USofA, so can't test.

So we just need to send an atmospheric probe to the nearest exoplanet and calibrate the models. They should get on to it, if they want to reach the destination before Webb runs out of propellant. /jk, ofc On a serious note, I find it mind boggling that they manage to capture any data whatsoever regarding atmosphere on planets so far away.

At work we have [email protected] address that forwards the email to everybody in the list (BCC to hide individual addresses). Perhaps something along those lines?

Yeah, I'm gonna say you don't really understand what energy density means. What's with the engine melting fixation? Magnets are, despite what some may say, in fact, not magic.

Are we talking about lifting gas or actual fuel? Why would the answer be any different than for any other aircraft? Jet A-1.

Orbital period at Earth surface is about one and a half hours. You can safely ignore it.

Such a planet can not form naturally, so your handwavium shell would need to be built before the spin up. In any case, if you match your spacecraft speed so it's zero relative to the surface, and fly on a tangential path with periapsis at the height of the docking port, you're good to go. Then again, a civilization that can shrink wrap a planet in unobtanium and spin it up, probably won't have much trouble just brute forcing the approach. For the curious visitors who don't have such capability, landing on the poles would be much easier.

A Mars cycler could be significantly bigger than bare bones, simce you only need to push it once. Once it's cycling you shuttle people and cargo on minimal crafts, but the cycler itself could be massive.

Science, recreation, communication (directional antennas), and, of course, docking.

Power transfer is fairly trivial, sliding or rolling contacts should have no problem with this. Trains do it all the time. Liquids (and non air gasses) are a bit tricky. Freely rotating fittings, aka rotary units, are available. If center of rotation needs to be clear of obstruction (at least occasionally) perhaps storage tanks on both sides and an automatic coupling / decoupling system? Air goes through the same hole people do.

Maximum number. That's why they don't bother with puny slow light speed coms and go with the good old FTL that any high school slime mold can make in less time than it takes to emerge from their fourth cacoon. My point is, presuming FTL coms is somehow possible (yeah I know all about the paradoxes, bear with me), they may consider it so basic that they don't even consider using radio since that's as obsolete as carrier pidgeons.

Betterment of everybody involved, I would hope.

What if it's an obvously poor choice? That is, from a standpoint of a civilistion that uses some trivial FTL method of communication which we haven't stumbled upon?

Why would you bother with their small fighters when you can just mount an engine to the nearest rock and rearrange their tectonic plates?

This. Put it in a tube and it's a ducted fan. Add a few more similar, a few a bit different ones and some sprinklers and you get yourself a jet engine. Then research a bit about existing and proposed air breathing engines and their role in getting to orbit.

TV's on in the background. The movie Absolute Zero is on. I've already seen this absolute dumpster fire of bad science, but I missed this little gem. For those of you lucky enough to not be introduced to this disaster of a movie with absolute zero real science, long story short, Earth's magnetic poles are shifting (over the period of couple of hours) which naturally causes the temperature in Miamy, FL to instantly drop to absolute zero. Anyway I just so happened to look at the screen when one of the scientists gives somebody a hand held compass, points to the S marking on it and instructs them to enter the bunker when the dial reaches the S mark. Movie scripts should be peer reviewed.

Launch cadence, presumably. Fast outer door means less air to pump before next launch, and since they dream about launching every couple of hours, this would help.

Can't help but think about all the dv wasted.

Is SpaceX pushing the sales of SS, or is this sat so big that FH is not enough and there is actual need for the SS capacity? Or is SX already offering SS at cost below F9/FH?

They seem to be perfectly happy with mechanical double door solution. They even claim that no air gets into the main chamber before the inner doors shut.

Usually I would agree, but nations have poured billions into this exact problem.

The fact that it doesn't exist, along side the cost of current suits, should tell you that it's not possible with current tech.

Gesundheit! What about that Tesla car?

Helicopter blades are constrained by the speed of sound. You don't want the tips to be faster, since a lot of aerodynamics bresk down above Mach 1.