farmerben

Well a Kardeshev 3 civilization has multiple Dyson Spheres and laser highways between certain stars. Would we be able to detect that? A small sample of Dyson Spheres could easily be mistaken for more distant galaxies behind the object galaxy. If the average of the galaxy was redder, we would just assume it is farther away. Right? I think it was Euclid who wanted to send signals to Mars by shaping Siberian forests into Pythagorean triplet triangles (3-4-5, etc). But if you arranged stars in triangles it would only be an appropriate signal in two directions polar to the galaxy.

Yes we could easily feed the population without pesticide, but you wouldn't have all the same fruits available all the time at your local grocery store.

Still the Appalachians were high altitude unlike the shallow seas at the Illinois and Wyoming basins. The Appalachian coal is in thinner seams of anthracite coal, whereas the latter two basins are bituminous and much thicker.

If you could safely and repeatable quench a superconducting solenoid, you could drive a current of protons at high energy. Perhaps for propulsion, or proton boron fusion.

It's entirely possible for a Kardeshev type 3 civilization that controls basically one whole galaxy would prioritize a super SETI program. It could be humans and our robots occupying most of the Milky Way. Maybe we still have loads of underutilized resources and go into decline anyway. The idea of colonizing other galaxies seems not just impractical, but unnecessary. But it would be nice to know if we are alone in the universe or not. It would take an insane array of lasers to send messages to another galaxy. Even then the signals take hundreds of millions of years to arrive. And we're more interested in receiving signals, than in sending them. There is no reason to assume that a Kardeshev 3 civilization would be visible at intergalactic distances. But it's possible they want to be. If so, what messages could they possibly send?

Arianne6, falcon heavy, the space shuttle, etc have two side boosters. The Soyuz had four and was the workhorse of global spaceflight for quite a while. KSP easily lets me have 6 or 8 side boosters using the same tech as I would need to do 2 or 4. So why don't we see more side boosters in real life? What are the best decoupling mechanisms?

I suppose its possible for an ISRU project to generate excess O2. In which case we would be looking for uses for it. Most other gasses are lighter and thus better for propulsion. In the case of Mars it might be possible to build an SSTO that runs on carbon monoxide and oxygen.

A Roman mile is 1000 double paces of a Roman soldier.

I hope we don't build another station for several decades. There are more important objectives like the Moon and Mars. But... eventually there will be another station. What should be the priorities of the next station? Centrifugal habitats for 1/3 and 1/6 g. Repositionable to the Moon, Mars or Venus. Inflatable and huge in size. ...

https://www.nasa.gov/smallsat-institute/sst-soa/deorbit-systems/ " In addition to drag sails, an electromagnetic tether has proven to be an effective deorbit method. This technology uses a conductive tether to generate an electromagnetic force as the tether system moves relative to Earth’s magnetic field. Tethers Unlimited (now Amergint Technologies) developed terminator tape that uses a burn-wire release mechanism to actuate the ejection of the terminator’s cover, deploying a 70 m long conductive tape at the conclusion of the small spacecraft mission. There are currently two main modules. The first, NSTT for NanoSats has a mass of 0.808 kg. The second, CSTT, is made for CubeSats and has a mass of just 0.083 kg."

What I'm hearing is that you need to nearly match the orbit of each piece of junk you want to catch. Nets are not going to work at high velocity. Now there is a graveyard orbit just above geostationary orbit. This junk is all moving with roughly the same velocity including direction. It's too far out to easily deorbit, (easier to crash into the Moon in fact) Out there a net that collects debris and keeps it concentrated makes some sense.

im not downloading but id love to see some screenshots

I wasn't specific enough. The cannons are in orbit. They don't need high muzzle velocity, because you get around 14 km/s relative by counter orbiting the target. Any hit is likely to shatter the target, but all the fragments will be going the same direction which happens to be the direction you need to deorbit.

I can at least imagine this. A time stopped bubble in an otherwise normal universe. Other alternatives are difficult to imagine.

What are some of the proposed methods for clearing orbital debris? My favorite idea is a cannon that shoots blocks ice H20 or dry ice CO2. With this the projectiles evaporate. Whereas using metal bullets limits the angles where you can safely use it without orbiting your projectiles. You need a cannon going in each direction, clockwise and counterclockwise as viewed from north pole. Use a cannon going opposite direction to the target. The cannons themselves need not be very powerful in terms of projectile speed. We try to intersect space junk near it's apogee and shoot it with a block of ice. Relative velocities will be in excess of 14km/s. The target could shatter, but all the small fragments will deorbit faster. Everything will be reduced to a lower perigee, I think. A miss is expensive in terms of payload cost, but not dangerous because it will ablate away into gas on its own. What else? Giant nets, magnets, radioactive tracers... Use tritium ice so at least you can easily track your projectile and tell how it disintegrates.

30 years and what do we have to show for it? We can't even breed mice in zero-G. Has there been any great discovery from this program?

According to wikipedia the altitude of ISS decays by 2km per month. There is still some air up there at 420km. So we have 13 years to wait before it de-orbits itself. Supposing we want it over the pacific ocean, we could wait till the last minute and do it on the cheap.

How many tons of fuel would it require to move the ISS into a lunar orbit?

That's way more practical than any asteroid mining mission I've heard.

In my model it's not like Back to the Future, where you disappear if you prevent your own birth. Einstein has a model where you can be your own grandpa. Your grandparents might not meet each other and have you, but they are likely to have other kids. Why be selfish? You're not allowed to become a serial killer who goes back a forth fixing your own screw ups, because hand waving argument. WWII might happen anyway. The Soviets and the Japanese were committed expansionists. It would just be different. I'll stick with my plan to save Abraham Lincoln, as I'm most confident he could improve things slightly compared to what actually happened. Orson Scott Card has an interesting story called Pastwatch: The Redemption of Christopher Columbus. In which by empowering the Native Americans just prior to Columbus' arrival, it is possible to avoid ecological devastation in our near future. A very good read. I also thought about saving the life of Jesus. We get way more parables and teachings. But a few things would be different.

My thought was to save Abraham Lincoln. Reconstruction would have gone much better. Our political landscape today would be quite different. Suppose Alexander lived to conquer all of India and beyond. Indian religion, philosophy, and mathematics would have permeated the western world early and completely.

In a way I'll be glad when we don't have a space station or a low orbit shuttle. The priorities are the Moon and Mars. Lets go already. No more distractions.

It is cliche to say that a time traveler could go back in time and kill Hitler thus stopping WWII. Let's juxtapose the question. If you could save the life of someone in order to change history for the better, who would you save?

Scott says the problem of space debris is more severe in higher orbits. Micrometeors and such a likely to break off pieces of the station compounding the problem. Too bad we can't push it past Earth's sphere of influence into it's own solar orbit.

Obviously it does better by not carrying oxidizer. Surely that's cheaper.