89

Reliability. Any rotating station needs non-rotating components: solar panels need to face the Sun, radiators need to be shadowed, docking points need to be non-moving, and so on. Making a rotating joint that can last decades is hard; if the hub of a rotating station seizes up, the resulting accelerations are likely to tear the station apart and kill ...


55

I'll add one or two more items to Mark's excellent list. Stability - large rotating platforms (and they have to be large to produce useful artificial gravity) are subject to all sorts of precession. Cost. The ISS was not cheap. Now imagine just getting maybe 50 ISS' worth of mass into orbit, assembled, and then enough fuel to spin it up.


39

It's a good question, followed by many relevant responses so far. I'll focus on the physiology aspects. Research had been conducted for decades prior to ISS launch on creating artificial gravity through spinning. The short of it is: the human balancing system (inner-ear plus brain) cannot not handle the spinning motion on the scales of what humans could ...


30

There was a proposal to add an experimental rotating habitat: Nautilus-X. One of those wonderfully tortured backronyms: Non-Atmospheric Universal Transport Intended for Lengthy United States Exploration - eXperimental. Its primary purpose was to extend how long humans could live in space not only through artificial gravity, but also storage for consumables, ...


29

A solar sail with an areal density of $1~\mathrm{kg}/\mathrm{km}^2 = 1~\mathrm{mg}/\mathrm{m}^2 =0.001~\mathrm{g}/\mathrm{m}^2$ is impossible by known materials science because graphene has an areal density of $0.77~\mathrm{mg}/\mathrm{m}^2$. Being a single atomic layer of a light atom, graphene is the absolute lower bound for the areal density of pretty ...


20

Direct measurement is difficult; I've seen some optical methods used but can't put a hand on them at the moment. Here are some calculated inner and outer wall temperatures for the Space Shuttle Main Engine, a regeneratively-cooled booster engine. The X axis is axial distance from the throat. I am pleased to see that both metric and English units are provided....


20

There is a extensive summary report on possible improvements of solar sail materials: "Ultra-Thin Solar Sails for Interstellar Travel - Phase I Final Report" December 1999, Dean Spieth, Dr. Robert Zubrin When reading this report one has to keep in mind that they only look for the properties of the sail itself, not taking into account structural ...


16

Though many say that success directly reflects how hard one works or how motivated one is, there is a huge amount of random "luck" involved; being in the right place at the right time, meeting just the right people who may be helpful later, etc. This leads to the following advice. Choose a path that has you doing things that you really enjoy doing: ...


15

It's not painted black. It just happens to be that color. Omitting paint saves weight. On 2017 May 24, Rocketlab itself tweeted: Why a black rocket? Carbon composite materials are black! Paint is heavy & adds another process. Plus, doesn't it look beautiful! #ItsaTest A different question would be why other launchers don't omit paint. I found an ...


15

The other answers good, but I think we miss something. Imagine a spacewalk around a rotating space station. With the current technology, we do need regular spacewalks. Everything dropped doesn't just float around. It is lost for good. The peripheral surfaces are hard to access from the outside - it would need mountain climbing equipment and skills. ...


15

O'Neil cylinders have a very large minimum radius of several kilometers for a reason, or several reasons in fact. One can't just spin up a small station to simulate gravity and expect a person to be comfortable when the acceleration at their feet is so much greater than the acceleration at their head, and it gets worse as soon as they start moving due to ...


13

A few months before Cassini made its mission-ending dive into Saturn's atmosphere, it skirted the region between Saturn's atmosphere and the innermost ring. From NASA Spacecraft Dives Between Saturn and Its Rings, emphasis mine, The gap between the rings and the top of Saturn's atmosphere is about 1,500 miles (2,000 kilometers) wide. The best models for the ...


10

To Study Zero G It's pretty hard to study zero-g if you're not in a zero-g environment. Now the question implies that we could mitigate some of the effects of zero-g, say on the crew's health, by simulating gravity. However, this ignores that the effects of zero-g on crew health is part of the ISS's mission: Research on the ISS improves knowledge about the ...


9

The basic visible design is usually two Y walls, North and South that carry the baulk of the heat generating equipment, payload or platform, though the latter is usually concentrated at the -Z end. at least two floors, one near the -Z end one near the +Z (Earth pointing) end. There could be additional floors at the +Z end for payload equipment that needs a ...


8

For Apollo: more nuts than bolts, but vastly more non-threaded connectors Table I of Apollo Experience Report: Spacecraft Pyrotechnic Systems, NASA Tech Note D-7141, lists all of the pyrotechnics above the Saturn booster (e.g. the CSM, LM, escape tower, etc.). Of the more than 210 pyrotechnic devices, 8 were nuts and 4 were bolts: 4 frangible nuts held the ...


8

I can't tell you a specific job, but I can help you narrow it down quite a bit. The best way to start answering this question is to go look at the job openings that Space-X currently has listed, and what the requirements are for those jobs. https://www.spacex.com/careers/ You can also go to third party websites like indeed.com that list the same jobs, but ...


7

Opinion-based, but I'll give it a shot. In the timeframe of one year, it's not possible to develop any new launch technology of consequence; we have to rely on existing launchers, with a couple of possible exceptions for launchers that are well in development. SpaceX has the best track record for high production rates and rapid scaling, so if I were in ...


6

To add yet another facet to a question which has provoked such excellent answers: WEIGHT A space station that is not spinning weighs nothing, however massive it is. To a first approximation, it could be held together with string. A space station which provides a 1g centripetal force means that the floor under your feet weighs 1 ton per ton. Which is a lot of ...


5

It's nuts to the shuttle, 16 to 9 Launchpad to stack connections 4 bolts with frangible nuts held each Solid Rocket Booster (SRB) to the pad. Each solid rocket booster has four hold-down posts that fit into corresponding support posts on the mobile launcher platform. Hold-down bolts hold the SRB and launcher platform posts together. Each bolt has a nut at ...


5

As an employee of SpaceX for many years, I can tell you that military experience is not something that goes very far in who they hire. Also, I can't think of anyone I knew there who had an electrical engineering degree. Your best shot at landing an engineering role at SpaceX is to get a mechanical engineering degree and have a strong interest in rocket ...


5

I would suggest the first thing is just to spend time reading about it as an interested layperson. Histories of rocketry, Hayne's manuals, payload user's guides and Wikipedia articles about specific rockets and systems, go to YouTube and find Scott Manley, Everyday Astronaut, and Curious Droid. How do the engines actually work, what kinds of fuels are used, ...


4

I'm no rocket scientist, but here's a skeleton of a checklist of systems to learn about. This is a wiki so I hope those skilled in the art will feel free to adjust/improve/rewrite. Tsiolkovsky rocket equation (informs about rocket sizing and fuel requirements for desired delta-V) guidance (information on position and velocity; where am I and where am I ...


4

Rocket designing is a complex task, and so is learning about it. I doubt that a checklist of any kind can be efficient. You need to find your own path of learning that best suits you. A good approach is to start playing with various rocket designs in safety of computer simulations. One particularly good and engaging "simulator" is called Kerbal ...


4

If I were you, I would do anything to do with repairing stuff. Airplane mechanic, ordinance technician, etc. There's a huge amount of demand for that kind of person. If that isn't your thing, you could try to work at one of the various command centers, such as the C-SPOC (Space Track). Just take a look at the Air Force careers website, start picking ...


4

Even small, relatively cheap steps haven't been taken to space Leaving aside the idea that there's such a thing as "cheap" in space: Sept. 14, 1966 - Gemini XI Artificial Gravity Experiment Gemini XI separated from the Agena with their spacecraft pointed nose-down toward the Earth. Conrad and Gordon maneuvered their craft to keep the tether taut ...


4

Yes, Venera-4 had a radiator-cooler in the center of its dish. From https://www.laspace.ru/projects/planets/venera-4/ Передача информации со скоростью 64 бита в секунду осуществлялась через параболическую остронаправленную антенну (ОНА) диаметром ~2,3 метра. ОНА состояла из жесткой центральной части, в которую был встроен радиатор–охладитель, и раскрываемой ...


4

It actually takes less pumping power to fill a tank from the bottom. Just like the pressure experienced by a diver depends on their depth, the pressure at the bottom of a vessel (whether a tank or a vertical pipeline) depends only on the column depth of the liquid within that vessel. The pressure in a line going to the top of the tank will be equal to the ...


3

Like most large asteroids, Vesta is held together by its own gravity, even if it's not held strongly enough to put it into hydrostatic equilibrium. As a result, if Vesta spun fast enough that it could provide a spin gravity at any point in its interior higher than its surface gravity, the centripetal acceleration provided by its own gravity would not be ...


3

Could you make a nuclear thermal rocket using water as a reaction mass? Sure! People have looked at that, as it would be nice to be able to refuel rockets in space from things you find (see Nuclear thermal rockets using indigenous extraterrestrial propellants) Could you launch from Earth with such a rocket? Well, maybe. Would it be worth it? Maybe not. Lets ...


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