# Tag Info

4

No. The prelaunch timeline for the crew was closely scheduled. Shuttle crews were awakened ~ 5 hours prior to the scheduled liftoff time and ate a meal shortly after they woke up and got dressed. Depending on the scheduled liftoff time, the crew may have been sleep shifting for a week or so prior to launch day. Source - SCOM, page 5.1-1 Normal Procedures ...

1

Your question is underspecified, but you might find something like TransHab (or other inflatable spacecraft designs) to fit the bill. There's already one such module attached to the ISS, so the principle appears to be entirely sound and practical. From this older NASA page on TransHab, you can see that the membranes are made from layers of nextel ceramic ...

0

Modern PHP runs on a Virtual Machine: A guaranteed environment that will exist regardless of underlying operating system or hardware. That is, core library functions that depend on features of an OS are not part of the VM, such as getting the PID of a child process after performing a pcntl_fork() in a Posix environment. Rather, language constructs like ...

5

Developing software for space applications is quite different from "regular" software development, especially when we're considering human spaceflight. If you want to develop critical software (i.e. software that, in case of a failure, can lead to loss of life, mission, and/or facilities) for ESA, you need to comply with the applicable standards defined by ...

4

Let's have a look on a 1998 paper on real time systems from CMU (Carnegy-Mellon Univeristy). Typical examples of real-time systems include Air Traffic Control Systems, Networked Multimedia Systems, Command Control Systems etc. In a Real-Time System the correctness of the system behavior depends not only on the logical results of the computations, but ...

3

What exactly makes PHP CLI fundamentally unsuitable to power all the math on board a space craft? ... What, exactly, is it about this that is so "crazy"? You seem to be taking the unsuitability of PHP as a given premise here. Why is that? PHP has two major deficiencies that are relevant here. One is that it's not very performant; the ...

2

One mission profile thought up for the VASIMR involves initially travelling closer to the sun to take advantage of the stronger solar flux to run the engine at high power, releasing a payload on a long coasting trajectory and slowing the launching vehicle back down to return to Earth. The idea is still a little half-baked at present (the engine performance ...

0

Amount of fuel/propellant needed to get the ship up to 0.05C (and then back down to stationary) for a 4.7ly trip. Russel Borogrove covered this nicely above. The answer is unambiguously "too much". When your required delta-V exceeds your exhaust velocity, your mass ratio shoots up exponentially. 0.05c is pretty gosh-darn fast... about the speed that fusion ...

3

Yes, ion engines are somewhat of a false economy in the sense that they rely on electrical power on top of their mass and their propellant (e.g. Xenon). So, compared to a chemical rocket engine where engine mass, thrust, specific impulse, plus propellant (and the mass of the tanks to store it) is about everything you need to plan an hypothetical spaceship, ...

4

Are you burning the hydrogen in a fuel cell to get the power for an ion drive? I don't think that's wise. You'd get more delta/v using the hydrogen and oxygen in a conventional rocket. A nuclear reactor fuel mass I don't think would be prohibitive. According to this site, generating 200 MW for a year would require about 5 tons of fuel. You're bringing ...

2

A spherical spinning station faces a number of problems. First, different latitudes will have different amounts of centrifugal "gravity" (due to different radii to the central axis), which is fine under some scenarios but not at all helpful if you only care about the parts that are at your target acceleration and maybe a bit at free-fall in the middle (which ...

2

As such, what I'm looking for is the derived equation from the rocket equation, where I can enter the target deltaV and the specific impulse of the engine, and the equation will spit out the fuel mass required per kg of payload. This may actually be within my ability to solve... but I've never been confident in rearranging formulae. Here’s the rocket ...

1

AU or any other space distance measure would not be good. As an example, once you reach Sun escape velocity you would be able to travel many AU for free outside the solar system without expending any further mass. It would be more meaningful Kg of fuel per Kg of payload per dV (delta velocity). dV is the actual measure of "distance" between orbits so to ...

2

It’s completely impractical to get to even .05c with either chemical or ion rockets. Here’s the rocket equation, rearranged to “mass fraction form”: $$M_f = 1 - \frac{m_1}{m_0} = 1-e^{-\Delta V / v_\text{e}}$$ where $M_f$ is the propellant mass fraction (the part of the initial total mass that is turned into rocket exhaust). The delta-v term is 15,000,...

0

There has been a lot of work on space nuclear reactors, though I don't believe any have used Thorium. It can probably be compared to these older reactors. Notable uses for nuclear fission reactors include: - Providing power in the outer planets and beyond where there's not enough sunlight - In those situations, having hundreds of kilowatts for radio ...

3

Yes. They have little in common, beyond both resulting in a mismatch between vestibular data input to the brain and what’s actually going on, resulting in symptoms that impair performance. In SAS, our best theory is that the shift from 1G to microgravity environment essentially results in a dropoff from baseline vestibular input that the brain seeks to ...

8

One could determine the planned locations of the crew during any given time by referring to the Flight Plan. For the reboost event described in the earlier answer https://space.stackexchange.com/a/39552/6944, we can look at where they were: At the initiation of the reboost, the shuttle commander would have been in the Orbiter, presumably with another ...

4

As noted in the comments, the priority needs for humans are air, water, sensible temperature and food. The survival time without food is weeks So at first guess the worst case survival plan with the astronauts is to make sure the suit can provide air and water, and adjust the temperature to minimize calorie consumption and then just wait and let body go ...

Top 50 recent answers are included