alpha
beta
preliminary
searching
wild-cat
advanced
analytic
avant-garde
examinational
examinatorial
examining
explorational
explorative
fact-finding
feeling
groping
heuristic
inaugural
indagative
inspectional
inspectorial
investigational
investigative
investigatory
original
preceding
tentative
testing
trying
zetetic
archaeological
deep space
experimental
ill-fated
in-depth
intensive
interplanetary
lengthy
long-range
piratical
recon
round-the-world
six-month
two-hour
two-week
uneventful
unman
upcoming
oratory