Thus it is obvious that there is nothing impossible with regards 
to energies here.   However, the energy required and thus the mass 
carried should depend upon the distance travel. 
	For short trips under 10 light years:
It would not be worth travelling above 0.5c, since accelerating 
and de-accelerating at 1 g requires about 1.47 light years (always 
talking proper distance as measured from earth) for each event.  
Thus as measured 
from earth the trip of 10 light years would take:
	1.47lys (5.8years) X 2  +  7.06lys (14.12years)  = 
10lightyears (25.7 years) (earth time)
                                       				                             
	This trip would have a mass ratio of 10.5 which requires 
10500 tons of H anti H to carry the 1000 tons of cargo.  (if some 
storage method could be employed to contain free electron and 
positrons, the required fuel would be the same as the payload 
(1000tons)!) 
      For a longer trip of 1000 light-years:
We prefer the occupants to have relativistic time dilation.  Thus 
at 0.99c, gamma(v) = 7.1 and at 1g, the trip according to earth 
would take:
 	58lys (116years) * 2 + 884lys( 893 years) = 1116 years
According to the crew the 884 lys would be reduced to 124.5 years 
and the acceleration and de-acceleration would take about 35 years 
each.  A total trip time of 195 years instead of 1116 years.   
This trip would require, as stated earlier 84 million tons of H- 
anti H (14200 tons with e+ e- method).     
The energies are clearly not impossible to obtain (even with 
current technology).  This, all for a rocket, carrying its own 
fuel.  There are other methods employing interstellar hydrogen or 
using stationary lasers which do not require the craft to carry it 
and other far more efficient engine designs (like the very 
theoretical quark / anti quark fuel source, I failed to keep up 
with). 
                 
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