Starfire was built into
what is commonly called an antizipper configuration. That just means
that the top of the booster section has a parachute attachment point and
that the parachute itself is deployed from the aft end of the body tube
instead of the forward end of the booster section. This arrangement helps
avoid "zippering" the body tube with the recovery harness if the parachute
is ever deployed while the rocket is traveling at relatively high speed.
Such as when deployment is well before or well after the rocket reaches
apogee.
If the parachute is
deployed out the front of a body tube while the rocket is traveling at
high speed, then the recovery harness will end up pulling on the lip at
the front edge of the body tube to slow it down. At very high
speeds, that will result in the recovery harness tearing a slot right into
the body tube and down a short length until the body tube has come to a
stop. This tear is what is referred to as "zipper" damage. An
antizipper configuration generally eliminates this failure mode.
However, sometimes, even with an antizipper configuration the end of the
body tube can still get damaged. This can happen on high speed
deployments where the body tube tumbles before the shock cord comes tight.
An antizipper band was added to Starfire in order to help prevent even
minor damage from that kind of scenario.
An antizipper band is a
steel band that is embedded into the lip of the body tube to prevent the
recovery harness from slicing into the body tube. However,
care must also be taken to ensure that this band does not slice the
recovery harness! Therefore, when ever I use an antizipper
band, I also use Kevlar for the recovery harness and embed steel bands
inside that Kevlar as well. That process is
shown here.