The frustrating communications blackout that can occur when a spacecraft reenters the atmosphere caused some tense moments in the earlier years of the space ageâ€”perhaps most memorably during the crippled Apollo 13 mission. But the phenomenon could also affect communications with new aircraft and weapons systems being contemplated now by the U.S. Air Force, which hopes to find ways to pierce the blackout.
Source: Piercing the Plasma: Ideas to Beat the Communications Blackout of Reentry
The 2006 conference revealed no lack of possible solutions. Ideas include designing the configuration of the craft so as to minimize the resulting plasmasonic sheath; building an â€œair spikeâ€ at the front of the leading edge that would protrude outside the plasma; finding frequency bands that might not be affected by the ionization; simply bullying through it with an enormously powerful transmitter; and using electrophilic injection, which means dispersing a deionizing substance, most likely water, into the plasma sheath to disrupt it. More exotic ideas involve employing high-powered lasers or ejecting a series of tiny relay devices, akin to messages in a bottle.