Posts Tagged ‘spacecraft’

I know that space tracking radar exists, but how far out in space can it see, and where are some of the sites located?

As opposed to close spacecraft near the Earth, is there something we could track a spacecraft with that was much farther away (such as if ET should someday enter our solar system with a huge spaceship)?

Satellites and space-based radar and optical devices? Or earth-based radar and radio stations, or both?

A spacecraft with a mass of 4000kg has 3 thrusters that allow both pushing and pulling. Thrust F = 800u where u is thruster input. How would you design a position controller using feedback from the spacecraft’s position system, which outputs in units of meters? Need to use a PD controller and need a state-space model …

Speed is measured relative to a stationary object. Velocity is determined by calculating the time it takes to travel a known distance from a stationary object. A cars speedometer measures speed relative to the stationary ground it is traveling on. An airplane measures speed by the same thing, by how long it takes to travel between points of a known distance on the ground.

So when it is said that a spacecraft is hurtling at 46,000 miles per hour beyond the orbit of Pluto towards the next star, what is that speed being compared against? In that part of space, there is no stationary object to calculate velocity. Is it still being compared to a stationary object on the surface of the Earth? At that distance, the Earth is traveling through space in orbit around the sun, which is traveling in orbit around the galaxy, which is traveling through space around who knows what.

So, what is the spacecraft traveling at 46,000 miles per hour from or towards that can be measured?

Matter occupies physical "space." Volume is a measure of the amount of space an object occupies. How could the fringes of the universe be expanding into non-space? How can one possibly explain the creation of space by the expansion of the universe? If matter can neither be created nor destroyed, how can space? If a spaceship were able to reach the outside of the universe and actually surpass it completely, venturing beyond the universe into "nothingness," what would happen? Would the spacecraft create more space due to its own gravity or would it simply occupy more space that was already there? Would it be destroyed or create some kind of logical paradox?

As far as I’ve seen, rockets lose their outer thrusters, and then ditch the hydrogen fuel tank when they set in orbit. I’m interested as to how astronauts are able to return back to earth from space stations or other space missions. Is there some kind of return spacecraft that is sent up with ample fuel?