[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Engineering Newsletter

Ram mass?

Ram Scoop collector
1000 km diameter scoop 200 tons. The speed of light is 300,000 kilometers
per second Assuming your moving at 1/3rd the speed of light (100,000
kilometer per second, or 1E10 cm/sec) with a scoop area of 1000 km
(pi*R^2=pi(50,000,000cm)^2 = 7.854E15 cm^2). You'd be scooping up the mass
in 7.854 E25 cubic centimeters of space.
A big question is the composition of interstellar space. A classic
assumption is that there is nothing but about 1 atom of hydrogen in a cubic
centimeter of space. More recently, people guess it might be less than .054
atoms per cubic centimeter or as many as 10. Even more recently than that
(say the last few months) it has been proposed that there may be a lot of
long-chain carbon molecules in space. Perhaps 60-200 atoms / molecules.
These small, dark, heavy molecules might be the missing 90-99% of the mass
of the galaxy (euphemistically called "dark matter").
So far, no one really knows. This is unfortunate, because the composition
of the interstellar medium makes a hell of a difference in the design of a
RAIR-based starship. Since we don't know one way or the other, let's assume
one atom per cubic centimeter at a proton mass of 1.673 E-27 Kg. At 0.333c,
using the above design figures, our 1000 km in diameter scoop, scoops up a
ram flow of 131.4 grams per second.

473 kilos per hour
4.14 million kilos per year.

Given a ship weighing hundreds of times that.  This isn't going to slow us
down much.

Of course the mass of inter stellar medium is hotly debated.  Some give
numbers 100 times heavyer, but others think its much less.


Kelly Starks                       Internet: kgstar@most.magec.com
Sr. Systems Engineer
Magnavox Electronic Systems Company
(Magnavox URL: http://www.magec.com/external.html)