Last night my wife and I unexpectedly observed an Iridium flare from
my back yard, which I estimated reached a maximum magnitude of about
-6. When I later checked this out on Heavens Above, it appears to
match a predicted pass for the Iridium 64 satellite.

We've both seen many of these events in the past, and this one seemed
pretty typical at first. However, a short time later (maybe 15 to 30
seconds?), we noticed a second satellite flare in the same location in
the sky. This flare was almost a carbon copy of the first (it
appeared and disappeared in the same places, and lasted about the same
amount of time), except that this one was significantly dimmer (about
magnitude -1).

The similarities between the two events suggest that they are related
in some way. Was the second event a different Iridium satellite (a
replacement sharing the same orbit), a piece of debris from Iridium 64
(seems unlikely), or a totally unrelated satellite (also seems
unlikely)?

I've never heard of a similar double-event, and am curious if anyone
can shed any light on the matter.

Thanks.