Can you build me a Death Star?
Yep! Just tell me where to put it.
Is there anywhere where this is discussed respectably? I wouldn't know where to look for these types of engineering/physics discussions, other than in the lay popular press. I'd be interested in evidence of some type of consensus amongst people who could be reasonably considered 'experts'.
Good question. If I find any reliable resources for this sort of thing in my travels, I'll let you know!
Thanks!
Now, in essence, it's not really that outrageous of a question. The idea of knowing the amount of fuel to get a rocket into orbit (including its fuel) is basically the same maths, right?
Oh, as an aside, I'll give another shout-out to on of my favorite sites for pro-space-development people
www.permanent.com is about harvesting near-Earth asteroids.
It is absolutely the same maths, kinematically speaking. The problem is that the motion often works out in ways that complicate the matter somewhat because there is more than just one force acting on the rocket, leading to extenuating circumstances and additional considerations that make the problem more than simply "I have this acceleration until tf, when I have this acceleration" or in our example, "I start with this energy, so I can go this far." When talking about rockets, for example, rockets have three degrees of freedom, and the condition of airflow around a rocket when moving at monstrous speeds leads to considerable reaction forces. When I was treating the rocket like a particle in a vacuum, my biggest problem was the mass function (something I wouldn't even let myself be bothered to solve for explicitly). In reality, my biggest problem would probably be the turbulent flow. But I'm speaking vaguely on purpose because rocket design and propulsion systems are at the summit, in terms of complexity, in aerospace engineering.
For people who like statistics, your average propulsion systems specialist is likely to make $50,000 more than the average engineer. That's because they're in high demand and there are very few people who go into the specialty because it's such a high-stress, high-complexity discipline.
Several video games I have played (Mass Effect, Freelancer, etc.) show space travel through the use of "gates" in space that the ship would fly through in order to gain the speed necessary to travel between planets or star systems.
Does this sort of idea have any realistic premise? Vague, I know, but I'm not sure of the science behind these types of space travel.
This is a cool question, as a fan of space travel it's something I have often fantasized about. From an engineering perspective, the answer is no: the best we have right now and the current banking of all our knowledge is in objects whose velocities are finite.
If I may be permitted to digress a bit, there are certain fundamentals that have been demonstrated physically that those fiction series represent. Between warpgates that literally teleport those that enter them and other machines that infinitely accelerate their patrons, only the latter has a physical basis (well, as we know it) in mass drivers. Magnetically-accelerated projectiles can, in theory, reach relativistic speeds, although the forces exerted on those projectiles would be astronomical. You could attempt to design for these types of forces, but accelerating to light speed in a short enough time would kill the people doing the accelerating: the human body can only take so much punishment.
If you look to the quantum species of physics, you see that there is a fair bit of research into the behavior of peculiar particles, such as certain particles that can go faster than light and other particles that seem to teleport. As far as practicality goes, even if we could reach parity and beyond, it'd have to take a long time.
Carbon nanostructures are a hot topic in research right now. I am afraid if you want to have accurate, up to date information, you will need to search the research literature on the topic. If you are lucky, you might find a comprehensive review, but these are no compiled very often, so the information might be outdated already.
Because it is such a hot topic, I don't think there is much of a consensus beyond "it might be possible, but we don't really know". Science moves forward by dissent, so a consensus is usually formed after a field has slowed down and the major discoveries have been made and accepted. I don't think this has happened yet on the feasibility of a space elevator based on carbon nanostructures.
Carbon nanostructures have been constructed in labs and are demonstrated to be quite strong.
From what I've heard, a space elevator that was constructed primarily out of these carbon allotropes would be able to resist the forces necessary for operation.
The brits have
Skylon. Allthough it's unmanned initially and not rated for human flight it is a fairly progressed R&D project of a single stage spaceplane that will be able to cut delivery cost from 15k £/kg to 650 £/kg to LEO. It will take a fair amount of innovation to make the program viable, but that was the same reference point when they started the Apollo program 50 years ago.
I could be wrong, but I feel US rocket science is populated by people who regurgitate Von Braun and Kuznetsov's work. There's very little real innovation compared to the amount of funds that has been channeled into rocket science. Do we need the other branches of science to spoonfeed rocket scientists with new research to get new and exiting programs started, or should the rocket scientists challenge(and fund) new research in other fields(like exotic materials) like they did with the Apollo program?
That's an interesting point of view. What makes you think that we're regurgitating the work of Von Braun and Kuznetsov? We've made great strides since them. Speaking overall, that is.
When talking of rockets directly, however, there is more cause for concern. There hasn't been a large national priority on the construction of large-payload rockets, so the technology hasn't advanced much beyond the adjustments necessary for your next deep space mission. Most of the development hasn't been in propulsion, it's been in the design of spacecraft and their component parts, and the application of robotics, which account for most of the technological difference between the rockets of today and that of the 1960's. Nevertheless, the field is advancing on all fronts, but in terms of new technology it's mainly held back because designing a rocket is
not easy. A lot can go wrong. That's why the axioms espoused by many of the great rocket designers from back in the day are still looked to for guidance. Even most of Von Braun's designs were catastrophic failures.
In airplane design, however, America is doing fantastically. Engineers are developing new and better technologies all the time and the United States is handily leading the world when it comes to aeronautical engineering.
If I had to attribute the gully between the relative "success" of these branches to anything, I'd say it was funding that was doing it. There's a lot of government cash that goes into the air force and in all NASA jet design and supersonic flow labs, and private industry is constantly trying to develop new ways to improve their airfleets. This itself is because there are a lot of goals that are easy to identify, and there's a healthy incentive to fulfill them: there is considerable talk about trying to build private jets that can go at supersonic speeds... and don't cause a sonic boom. How it's done is pretty cool, but the status of airplanes as high-technology, high-expense items means that, as long as there exists an absurdly wealthy upper class, the industry will do quite well when it comes to innovation.
As for rockets, well, it's much more difficult to design a rocket than an airplane, and because the number of people who specialize in that field are shrinking the knowledge-base for designing a rocket from scratch is also starting to disappear. There is very, very little incentive to go into rocket design because it's twice as much work for almost a third less of the money.
So what are the chicks like down there?
Not much future here with the space program closing down. I hear China's hiring!
The chicks are fine, and so are the women.
Aerospace engineering is a mixed bag here. The United States is the world leader in terms of both numbers and quality, but our space program definitely isn't what it used to be.
As it happens, the space program is still the top in the world.
I think that is exactly the idea most researches have in mid when they want to make a space elevator cable. But to make such a rope, one needs threads of the appropriate length and getting those is the whole problem.
A space elevator would likely operate pneumatically as opposed to with pulleys and cables. It's more efficient that way.
Seems sort of trivial, but did you build your own amateur rockets ever and launched them just for fun?
Once a soda bottle rocket, but it didn't go far
You can't build your own rockets and launch them if they're bound to go very high at all. The Air Force doesn't like it when you do that. I know around here plenty of aero students have gotten in trouble for launching rockets without a permit.
As I said, it is a hot topic and to get accurate information you need to get to the actual research literature. That paper is just about 3 months old, so any writeup of the topic is unlikely to include it. Apparently they made quite some progress since my last course about nanosystems 3 years ago.
