MARV (sometimes written MaRV) stands for
MAneuvering
Re-entry
Vehicle. Related to the
MIRV (MIRVs can be MARVs), a MARV is an individual
re-entry vehicle which does not follow a strict
ballistic trajectory, but maneuvers or changes direction as it comes down. These can be guided MARVs, which might
navigate using
gyros, or they might simply be RVs with an
asymmetric shape, causing them to spiral or tumble as they come down (sometimes called
c-MaRV by the
BMDO, for crude-MARV).
The primary reason for having MARVs is to defeat ABM systems, whether they use KKV interceptors, directed energy weapons, nuclear-tipped interceptors, etc. MARVs nearly always imply a penalty in accuracy, at least unless navigating RVs are used. These, however, become vulnerable to soft kills from nuclear interceptors or jamming facilities. Note that not all MARVs are intentional. The Iraqi Al-Husayn and SCUD missiles fired at Israel and Saudi Arabia during the 1991 Gulf War nearly all became MARVs when they broke up upon hitting the atmosphere and began to tumble erratically, usually separating into multiple pieces. This was one reason that the Patriot missile defense system failed to perform properly, although many other factors would have been sufficient causes for its failure.