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Hmmm, thought I "kinda" said that :

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I still want my quarter.

Anyone in my age bracket (40+) surely played Asteriods in the arcades.

That game was a perfect example of how vector math applies to a rocket. Remember when you would run from the little saucer as fast as the ship would fly ? And then when it was safe, you'd have to turn the ship around and apply the thrust just to slow down and gain control.

And that was only on 2 dimensions, imagine trying it in a "3-D" environment 

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ok,ok*gives brett his damn quater*

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Any of the brighter designers would have "retro" (meaning reverse or backwards) rockets or engines already facing the other way!!   

Yes, it's more efficient to use smaller maneouvering thrusters than another "equal and opposite" rocket.

As to mechanical means - an internal "flywheel" type arrangement could be considered, using the torque of a spinning mass to rotate the overall ship.   I think, however, that given the masses involved, thrusters are more efficient.

(Where Andy Libby when we need him?)



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That's the point,,  you don't want 2 at all. You want to use 100% of your engine mass accelerating/decelerating,, any deviation from that adds time to the trip (geometrically I might add).. the shortest possible trip would be accelerating full speed to the 1/2 way point, and then decelerating to a stop.

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I believe you're confusing "mass" with "density"...

Weight is a function of  Mass X Gravity .. on Earth that gravity equals  (32'/sec^2)

Kilograms and Pounds can only be linearally converted on Earth..  

'Kilograms' are units of Mass,, the English-system equivelant is the 'Slug'...

Pounds are units of force (Mass X Gravity),, the Metric-system equivelant is the 'Newton'...

Ever notice that rocket thrust is always given in either 'pounds' or 'newtons',  never 'kilograms' ?

I believe the moon's gravity is 1/6 that of Earth, so here goes the comparison:

An object weighing 6 pounds on Earth weighs 1 pound on the moon.... An object with 6 kilograms of mass on Earth STILL has 6 kilograms of mass on the moon .


Or,,  carried to the extreme.. in zero gravity nothing "weighs" anything,, everything still hass "mass"   

I did say that I could be confused !.....it does explain one thing, though.....it takes less time to get home from the moon than it does to go there......its all downhill(relatively speaking), with only one sixth of the escape velocity required to break free of the moons influence and allow the earths to take over.....5/6ths of the trip back is accelerating.....without further motive force being applied internally at the vehicle........I guess thats why long distance space travel so far, has made use of other celestial bodies and their imparted gravitational influence to the traveller............Americans call it the singshot effect.....in England a slingshot is a catapult .

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We were talking about a Jumbo being moved through space by "the tiniest rocket". This is what I based my comment on. Another "tiny one" would not make that much difference. In fact, depending on the definition of "tiny", it may even have less mass than the thrusters you speak of.

As once a rocket propelled object reaches it's required velocity and remains at that velocity until acted upon by some opposite force (inertia), the extra weight (little as it is) I don't feel would make a difference in this particular scenario.