Reply To: T-shirt designers unite and take over

[annodomini2]

Jolly Roger wrote: Here is a site for scifi writers that has some interesting information.

http://www.projectrho.com/rocket/rocket3c2.html#table

It states that we may expect a Hydrogen-Boron rocket engine to have an exhaust velocity of 980 km/sec, thrust of 61 kN and engine mass of 300 metric tons.

We expect an FF engine to have a mass closer to 3 tons, but perhaps the other numbers are in the ballpark. If so, our spacecraft will have a top speed of 980 km/sec or 0.33% of the speed of light. I think that relativistic effects will be minimal.

With a top speed such a small fraction of the speed of light, extra-solar missions will be limited to robots, sleepers or generation ships. However, it should do fine for getting around the solar system, even out to the brown dwarf, Barbarossa, thought by some amateur astronomers to be orbiting the Sun, currently at about 218 AU.

http://www.metaresearch.org/msgboard/topic.asp?TOPIC_ID=770&whichpage=33

The critical factor then is the thrust. At 61 kN, our 100-metric ton ship will have an acceleration of 61 cm/sec^2. It would hit top speed in a few weeks, but it would still take 13 months to accelerate, coast/cruise, and decelerate to Barbarossa. A larger ship, with the 2,000 ton mass of the Space Shuttle, would take 25 months for the same journey.

The brown dwarf Barbarossa is not to be confused with the asteroid of the same name. Barbarossa may be the Dark Star Marduk/Nibiru that author Andy Lloyd is looking for.

http://www.darkstar1.co.uk/solution.html

The maximum speed of the ship is not limited by the exhaust velocity as the action is relative

Due to newtons 1st law:”Every body perseveres in its state of being at rest or of moving uniformly straight forward, except insofar as it is compelled to change its state by force impressed”

There is very little friction in the approximate vacuum of space so relatively no force to slow the ship

Due to Newtons 2nd law: “The change of momentum of a body is proportional to the impulse impressed on the body, and happens along the straight line on which that impulse is impressed”

As the action is relative the force remains constant

And Newtons 3rd law: “For a force there is always an equal and opposite reaction: or the forces of two bodies on each other are always equal and are directed in opposite directions.”

Just because the ejected mass is stationary or moving away from relative to the earth it is still travelling at 980km/sec relative to the ship

If your statement was the case we would never achieve orbit with current technology

The speed limitation is mainly one of fuel, the ship will keep accelerating forever with infinite fuel and time, however as you approach the speed of light the net acceleration drops significantly as the relative mass increases.