4. Joann Evans (Space travel hazzard),
Once past the local E/M-L2 mutual gravity-well or nullification zone,
there really isn't all that much gravity influencing the continual
acceleration upon a bone-less body. Once past the grand nullification
zone that's situated between us and Sirius is where the real speed can
be obtained, up to perhaps 10%'c' seems doable, or at least until you
run yourself into a speck of sand or just overheat from the ISM
friction of Vt/slug factor of perhaps as great as 1e9 atoms/m3 or even
as little as 1e6 atoms/m3 is somewhat testy if having to displace your
large craft and yourself within through that nasty muck at 3e6 m/s
without becoming a comet that's losing it's cool.

Perhaps evolving into having an exoskeletal body is best for such space
travels.
~

Life upon Venus offers energy to burn within a Township, Bridge and
ET/UFO Park-n-Ride Tarmac:
http://guthvenus.tripod.com/gv-town.htm
The ESA Russian/China LSE-CM/ISS (Lunar Space Elevator) as situated
within ME-L1/EM-L2
http://guthvenus.tripod.com/lunar-space-elevator.htm
Venus ETs, Earthly ETs plus another updated topic list; Brad Guth /
GASA-IEIS
http://guthvenus.tripod.com/gv-topics.htm

BTW; I've realized that other life must have been possible upon Venus,
at least as of nearly 6 years ago when I'd first interpreted upon one
of many radar images upon what looks quite community like, although
there's also somewhat other interesting natural aspects of such images
that doesn't quite jive with the purely hot and nasty sort of world as
having been painted by our MI5/NSA~NASA rusemasters.