sevenperforce

For Venus, just bioengineer some sort of algal colony that takes in sunlight, metabolizes CO2 and produces O2 in a bladder that slowly inflates/grows, and reproduces by budding. Seed the Venusian atmosphere with the stuff.

That's the spaceship end. IDK about the booster end.

Plants grow toward the light, not away from the ground, so gravity won't make much of a difference there. Planted in lower gravity, crops which grow larger and produce more will quickly be selected for, so even if it is not an immediate outcome it will be the eventual outcome.

Bad news: Mars cannot support life in the long-term; its gravity is too weak and it has no magnetic field and so it will steadily lose atmosphere. Good news: Mars has an atmosphere-loss rate on the scale of millions of years. Good news: We can change the climate of Mars on a timescale a thousand times faster than it naturally loses atmosphere. Bad news: A million years divided by a thousand is still a thousand years.

Probably only in a small focus region, though.

I had no idea how big the sunshade was. Holy crap.

How cool will it be if they just fuel it back up and fly it again? And again. And again. And again.

Terraforming: Level 0: We can live in habitats that are open on the bottom. Level 1: Any measurable increase in global air pressure. Level 2: Global air pressure and temperature increase enough to allow SOME sort of Earth life (however modified) to grow outside of constant pressurization. Level 3: It becomes possible for people to move from one enclosure to another with no more hazard than, say, Alaskan snorkeling or Mt. Everest picnicking. Oxygen mask may be required. Level 4: Large-scale food crop growth is possible using only irrigation and perhaps a greenhouse. Level 5: An unprotected human can survive outside, albeit briefly. Level 6: Relax on the green slopes of Olympus Mons, sipping Martian-grown wine under a tall tree and watching the Solset with your partner, your Martian-born children, and your pet cat Fluffy.

Usually around 1800 kg/m3.

World population will flatten because people will start dying. This is no different than how it used to be, of course. In the past, world population grew linearly because we were at the limits of our production capacities and so people on the edges starved to death, or died early due to disease and wars. But we've collared the first and second horses of the apocalypse and slain the fourth. Without disease and wars killing people off, population growth has turned from linear to exponential, and so when the third horse catches up to us, it will be REALLY bad.

At the very least, one should be proficient in at least one programming language before trying to learn create another. C++ is very easy.

Sure. But it takes land to do that. And since it's out in the wild, it also takes pesticides, insecticides, and those are potentially harmful to the environment, and considering how it's a continuous problem, it'd be great if we could just get rid of it forever, right? Well, we can. There's also issues of certain resources being used inefficiently. But all of that can be dealt with if the environment we're growing the crops in is entirely artificial and is a closed system. Sure. I just mean that as long as someone is trying to use their arable land to generate income, growing GMO corn is just about the best per-acre ROI. Mostly because corn is so efficient at converting light into food. This is not necessarily a good thing. It is just a fact. Oh, yes, there are things that can be done. That's the whole point. If we progress with our current system, we will run out of food. If we lower our consumption and change our mechanisms of production, we won't. Until new systems are economically more advantageous than the alternatives, however, they won't be done. If someone could make money off of a vertical farm floating a few miles offshore, then they would have already done so. This is the sort of thing we should be investing in. The consumption/production balance tipping point keeps getting pushed ahead with every advance, but the push-ahead is smaller and smaller each time. Eventually we will reach the point where we say, "We should have been investing in dramatically new systems a decade ago." Unless we start now, that is. Yep. I just hope that the answer isn't, "Oh, hey, let's start growing corn on all the national parks too." Because A, that's horrible, and B, we're only pushing out the inevitable tipping point by a few decades at best, and the problem then will be worse. Beans take carbon dioxide and water, absorb sunlight, produce glucose chains and oxygen.

There may be some high-altitude lichens that could either be bred or genetically engineered to grow at sea level pressures on Mars. Or, I dunno...hydroponic spinach. They have done some research on the effects of low pressure plant growth. Transpiration (the rate at which the plant can exchange carbon dioxide and oxygen with the air) actually goes up, but growth rate goes down.

Anything that turns sunlight, water, and CO2 into calories would be suitable for colonization, if we could find a way to grow it on Mars. Corn has been bred to be the highest-performing crop for our purposes on Earth. It's not actually good for us or our livestock, but it is hardy, weathers temperature variation well, and does a very good job of converting sunlight into calories, which is what we need in order to maximize the immediate profitability of arable land.

Storability is a big mark in favor of certain hypergolics....specifically, the ones always in use. Hypergolics aren't necessarily storable. But we use the ones that are. You could, theoretically, have non-hypergolic props that are readily storable or hypergolic props that are not storable. Also, hypergolics aren't necessarily pressure-fed. You can pressure-feed cryos and you can pump-feed hypergolics. You could have an electric pump for hypergolics as easily as you could have for cryos. Some pump-fed hypergolic engines have pretty respectable specific impulse. The choice between pump-feeding and pressure-feeding is similar to the choice between cryos and hypergolics (weighing reliability and dry mass against performance) but they are separate questions. There are roughly six factors to consider in choosing a propellant combination: Toxicity and handling Bulk density Ignition reliability Storability Thrust Performance When you are dealing with reusable or refuel-able systems then questions like availability (for ISRU) and chemistry (e.g., avoiding coking) also come into play. Propellant Toxicity/handling Density Ignition Storability Thrust Performance Hypergolics Very Bad Good Very good Good Good Bad Kerolox Fair Fair Fair Fair Good Fair Methalox Fair Fair Good Fair Fair Good Hydrolox Bad Bad Good Very bad Bad Very good Solids Good Very good Very good Very good Very good Very bad

That's what I was going to say. Falcon 9 is so much wider.

Because coming up with a brand new language is a lot more work than just taking a ready made language and compiler and work with stuff that's been bugfixed and developed for many years by individuals far more experienced and skilled than you. This.

Right; I was agreeing. The majority, in fact. At least in developed countries. Growing corn is pretty darn energy efficient. We shouldn't punt to this, I don't think.

That's about what my first successful test run was, too. Going to see if I can do some action-group magic with elevators and canards.

People don't realize how limited our resources are. Earth only has enough arable land to produce crops to feed something like 3 billion people at average per capita consumption in developed nations. In other words, to bring Earth's current population to the 21st century, we would need the resources of almost three Earths.

Lightspeed is a hard stop. We will have the technology to terraform Mars trivially before the first manned generation ship reaches Alpha Centauri (and, most likely, finds another Venus or another Mars). RE the OP topic: If we can get Mars to the point that we can move from building to building with no more danger than, say, snorkeling the Great Barrier Reef, and if we can get Mars to the point that we can grow life-sustaining crops in the open air...well, that's terraformed.

Very possible. Let's just build the BFS on Mars and then fly it back. That way we won't need as many launches of the BFR.

Infinite fuel and ignore max temp? I mean....how fast do you want to go? I can do double solar escape velocity within sight of KSC.

Better yet, just launch the launchpads along with the rocket and then you don't ever have to release the launch clamps in the first place! No turnaround required!

Easier to just test as they fly. Entry is always more stressful than ascent, so if there is a problem, it will be more likely to go kablooey after successfully delivering the upper stage. I noticed that they deployed the grid fins almost immediately this time, instead of waiting until just before the entry burn. Neat tracking on the droneship cam!