# Intersecting crafts at significant % of light speed

## Main Question or Discussion Point

Hi,

I am currently plotting a piece of writing and wonder if anyone could give me some feedback on the following: -

Space craft 1 is a beam/ sail craft with constant acceleration of 1 G to a speed of 0.2c. It travels along a straight line between Tau Ceti and Sol (circa 12 ly). Ship time for the journey is circa 60 years and observed time circa 61.5 years.

Space craft 2 is a Gravitational craft on an intercept course with space craft 1. It has gravitational shielding and as such is able to accelerate and manoeuvre at high speed without liquefying the occupants. It travels at 0.8 c. For the sake of argument the course it takes is an altitude of a (more or less) isosceles triangle between the three stars. This is a distance of circa 10 ly. Ship time for the journey is circa 12.5 years and observed time circa 21 years.

My back-of-a-fag-packet working is that it would take space craft 1 circa 30 years observed time to reach the mid-point of its journey. Therefore space craft 2 would need to leave circa 10 years after the departure of space craft 1 to intersect it.

Is this all accurate or am I missing a trick somewhere?

Chinspinner

Edited to add: also, can anyone point me in the direction of some decent literature on gravitational shielding?

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PeterDonis
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My back-of-a-fag-packet working is that it would take space craft 1 circa 30 years observed time to reach the mid-point of its journey. Therefore space craft 2 would need to leave circa 10 years after the departure of space craft 1 to intersect it.
This looks about right, yes: about 30 years observed time for #1 to reach the rendezvous, minus about 20 years observed time for #2 to reach the rendezvous, gives about 10 years.

This looks about right, yes: about 30 years observed time for #1 to reach the rendezvous, minus about 20 years observed time for #2 to reach the rendezvous, gives about 10 years.
Thanks very much.