I'm a database newb, so please forgive the following, potential stupid,
question.

We have research trips that we participate in, collecting data every few
minutes.  That part of the database is fairly simple.  One thing that we
would like to keep track of is who was on the trip.  There is a pool of
about 10 people who can go, with some trips having 1 person, and some
trips having 5.  

Some options I've considered.  

In the "trip" table, which contains meta-data about the trip, have 5
columns called P1, P2, ..., P5, putting one persons name in each (or null
if there was no Px).

In the "trip" table having 10 columns, 1 for each member of the pool,
simply putting a Y/N in their column for each trip.

Both of those "solutions" have problems.  What if we take 6 people on a
trip?  What if the pool of 10 grows to 12 and/or people leave and we hire
new people?

Is there a better (ie more flexible) method for storing data like this?

Thanks!
Bruce