Nibb31

- Comfort is subjective. While some people might be confortable in a spinning habitat, others might get dizzy or nauseous. The same is true for microgravity itself. So whether microgravity or centrifuge-induced is preferable might depend on the individual. Some people might prefer one or the other. - This depends on the structure, obviously. If you design the structure to be able to bear the load that it is designed to bear, then it should be able to bear that load, shouldn't it? One thing is for sure, you wouldn't want one of those silly rotation joints that you see in science fiction movings. It simply adds a whole lot of complexity and possibility for failure. You would rather rotate the entire ship, like in Interstellar. - We don't know. Artificial gravity might even be detrimental compared to microgravity. You might suffer from equilibrium and internal ear problems, causing motion sickness. - The sizes and RPM depend on how much artificial gravity you would need, if you need it. The smaller the vehicle, the faster it has to spin, obviously, and the more negative effects you get due to the Coriolis effect. The truth is, we don't really know the answers to any of these questions, because there has been no proper experimentation in artificial gravity. We can only extrapolate based on what we do know from operating centrifuges in Earth gravity. We don't know whether 0.1G is enough to avoid most microgravity problems, or whether you need 0.3 or simply 1G. We do know that a centrifuge adds a lot of complexity, cost, and risk. We also know that astronauts have been able to live and work in microgravity for extended periods. We also know that we can use medication and exercice to fight most of the detrimental effects of microgravity. So for the moment, nobody is considering artificial gravity as an actual necessity in the foreseeable future.

Soyuz/Shenzhou also happens to be pretty clever design when your vehicle is expendable. It minimizes the weight of the parachutes and heatshield while providing ample interior space, including crew facilities (a toilet!) and bulky mission equipment. It's so good actually that Boeing, Lockheed, Andrews, and Northrop used the same layout for their CEV proposals, not because they copied Soyuz, but because it's a logical way to design a manned spacecraft. General Electric also had a similar proposal for Apollo.

Pegasus is a rocket, not a spaceplane. There can be manned spaceplanes, unmanned spaceplanes, manned rockets, unmanned rockets, manned helicopters, unmanned helicopters. The term "drone" designates an unmanned aerial vehicle, whether it's a helicopter, a plane, a quadcopter, a rocket, or anything else that flies in the air. There are also drone boats, drone tanks, drone submarines, yet they can't be called UAVs (obviously). The term "drone" is just too vague to be meaningful. All rockets since the old V2 can be considered UAVs, since they had their own avionics and guidance systems. All satellites since sputnik can be considered UAVs, since they are unmanned. Even manned rockets like the Saturn V or the old Vostok R7 were never piloted by a human. The distinction makes no sense. All modern launchers are unmanned, they're aerial, and they're vehicles. They fly to orbit to launch payloads on their own, using their own avionics and guidance systems. So they can all be considered "drones".

PR is a secondary goal for a rocket. The primary goal is getting to orbit. If an unpainted tank offers better performance, the PR folks' job is to explain why it's orange and not white.

The energy involved in moving a 36000km conveyor belt at 1500km/h is huge, also starting and stopping it is going to cause tremendous stress on the system. It's amazing how people tend to believe that a space elevator would be cheap. The cost of developing, building and operating one would be far from cheap. The cable cars are always going to need amounts of energy to cover the distance at any reasonable speed while fighting gravity, and energy isn't cheap.

You need at least two landers. One for cargo, habitation, and some sort of rover, the other for the MAV.

Then your question is about SSTO spaceplanes, not UAVs. How the vehicle is controlled is irrelevant. Getting to orbit is about reaching orbital speed, not altitude. To accelerate to 27000 km/h, you need a lot of propellant. Conventional rocket: engines + propellant + payload. The payload fraction is typically less than 0.5% of the gross takeoff weight of the rocket. Space plane: engines + propellant + wings + landing gear + hydraulics + TPS. Without even adding a significant payload, your vehicle is already too heavy to reach orbit. This is why nobody has managed to make an SSTO spaceplane yet.

Please tell me you're joking and you didn't take that IXS Enterprise thing seriously.

Not necessarily, because the cycler needs its own propellant to adjust its orbit on each pass. A cycler between Mars and Earth is effectively in an excentric solar orbit. This orbit will only line up perfectly between both planets on vary rare occasions, so you are going to have to adjust the cycler's orbit on each trip. Those manoeuvers are going to be very expensive in propellant due to the mass of the cycler. And the propellant for those manoeuvers is going to have to come on a supply ship, which in turn is going to need more propellant to carry that propellant. So basically, unless the cost in propellant to adjust the cycler's orbit on each pass is lower than the cost in propellant to simply add a proper hab module to your supply ship, it's not worth it. I suspect it isn't.

The reason for the gull wing was to provide better visibility for ground attacks.

It wouldn't. There would be deniers, studies, reports, more studies, protests, conferences, political debate, and many hard political decisions to make. It would take months or years before we actually reach a consensus that something needs to be done NOW (or 4 years ago). Then you have to make all the tough political decisions about WHAT to do exactly. Even in this thread we can't agree on a common course of action, so imagine what it would be like in an emergency G8 or UN conference. Imagine the problem of evacuating North America, since it's going to be turned into a giant crater. Does the US Congress peacefully and unanimously agree to dissolve the USA, give away their assets (including military stuff) and send everyone abroad? How many countries are going to agree to accept the millions of refugees? Under what conditions? What about land owners, corporations, financial interests, insurance companies? Who defines who the winners and losers are going to be after such a devastating event? If the decision is made to attempt to deflect the asteroid, there are the questions of who is going to pay, which companies get the contracts, who commands the mission, and what happens if it fails. The simple act of nominating a science committee to evaluate solutions will require months of negociation. It might look obvious that we would all unite under the banner of Humanity in times of crisis, but reality is much harsher when it comes to making the political decisions and reaching agreements, especially when there is so much to lose and nobody wants to lose more than the other guy.

What's the use of being "faster" ? Those rocks aren't going anywhere and isn't any particular emergency to get the data. The rover has literally all the time in the world. It doesn't have to return to the base every day to eat or sleep. It doesn't have limited oxygen or EVA time and it doesn't have to return to Earth at the end of the mission. One could argue that the MERs returned more science in 10 years than a manned landing could have returned in 1 month, for a fraction of the cost. If anything, it's faster to send a rover now and have it pick up a rock in 6 months than to wait until we're ready to send a human pick up the same rock in 20 years. Also, we can easily send hundreds of rovers to cover a much wider area over a much longer period. A human expedition would only last a couple of months and cover a limited range around the lander vehicle. In terms of science returns, coverage is more important than speed. Geology certainly isn't a good enough reason to send humans to Mars.

The only point of an Aldrin cycler is that it allows a large habitable area. For anything else, including crew, supplies, propellant, equipment, and spares, you still need to match the orbit of the cycler and leave that orbit when you arrive at your destination, which requires at least the same amount of dV as if you were going direct. The cycler itself also needs to readjust it's trajectory at each end, which is going to cost extra dV, for which the supply ship needs to bring the propellant. All in all, it's not worth it.

In 4 years, there isn't much you can do. If you know the impact area (which isn't realistic) then evacuate as many as possible. On the rest of the planet, build thousands of shelters as deep as you can and brace for the impact. Stockpile supplies, vehicles, communication equipment, breathing equipment, generators, seeds, genetic material, and archives. You would need to design the equipment so that you can pull it out of the bunker and jumpstart something like a Mars colony. Even if only a small percentage of those shelters survives the impact and its aftermath, it would still save orders of magnitude more lives than sending people off into space. We can't even agree on greenhouse gas emissions, and our survival depends on it. It would take more than 4 years to schedule the G8 meetings to discuss the problem. In the given timeframe, there could be no worldwide cooperation. Each nation would have to take it into their own hands.

You need to define drone. The proper name for a drone is a UAV: Unmanned Aerial Vehicle. Other than that, UAVs can be of any type: plane, helicopter, quadcopter, boat, rocket... By the proper definition of drone, an unmanned rocket or spacecraft is already a drone. I think what you're talking about is an unmanned spaceplane or SSTO or both. So please reformulate your question with the proper words.

It isn't NASA's job to lay out its own plans. NASA gets its goals from laws that emanate from the US Congress, which are either followed up or not with funding. If Congress can't get its act together (see what I did there?), it's not NASA's fault.

One of the reasons there are no payloads is because nobody in the science community wants to design a mission that relies on it because it might be cancelled. The reason it might get cancelled is because there aren't any payloads for it. It's a vicious circle.

Never heard of any serious proposal like that in the last 20 years.

It seems big to be just a cargo spacecraft. It looks a lot like a Russian DOS module.

There are some local resources, but you can't "live off the land" like the first American colonists planned to do. You might be able to make bricks and mortar, but anything more complex is going to require multiple extraction, transformation, and manufacturing steps. It will be a long time before you can make spacesuits out of domestically spun fabric, or filters, or rubber seals, or lubricants. Even transforming metallic ore into something that can go through a 3D printer is going to take a pretty large effort.

No, there were quite a few failed colonies in the Americas before Jamestown become sustainable. Most of them were failures because they were unprepared and uneducated. They typically ended up in cannibalism or everyone dead. A one-way trip would have chances of ending up the same way. There are many things that can go wrong: your crops might catch a disease, or provide a lower yield than expected, an ISRU machine might underperform, or a single technical failure on the life support system can kill everyone in minutes. If for some reason all of your EVA suits are damaged or worn, then there is no going outside to fix some essential piece of gear until you get a replacement, and so on... Space is a harsh environment. Anything you send will be designed for a limited lifetime. In those conditions, nothing can be permanent. Your station has to be temporary. Who wants to live permanently in places like Antarctica or the ISS and never come back anyway ?

Not necessarily. What works for one company in its environment might not work for others. With Ariane 6, ESA is trying to cut costs through lower production costs instead of reusability, because they have different requirements. Reusablility is not a Holy Grail. There are several ways to skin a cat. And even if reusability is achieved, we are only looking at a decrease of 10 or 20% in launch costs. It is a great incremental improvement, but it's not a revolution.

I don't think an expedition to Mars is likely in the next 50 years. Beyond that, we're in science fiction territory, so anything goes...

Any evidence or comparisons or examples to back that up, or is it just an empty claim?

ISRU would be great for followup missions. It would take several cargo expeditions to set up and validate the equipment so that humans can rely on it to return. For a "Mars as soon as possible" scenario, the development and validation of the ISRU equipment in addition to a Mars expedition spacecraft would take longer than the simple development of a Mars expedition spacecraft.