AThe sun itself gives of an almost incomprehensible amount of radiation, heat and energy, enough to span the 93,000,000 mile (149,668,992 km) distance between it and the Earth, which receives all its heat, light and energy over that tremendous distance. As the ship approached the sun, the radiation become much more intense, enough to disrupt (or perhaps absorb) all radio signals being sent back to Earth. Icarus II enters the dead zone a week earlier than the crew had calculated. The Icarus I also encountered the dead zone during it's mission seven years ago.
AThe flashing images were of the Icarus I crew members. While searching Icarus I, Searle comes across the photo of the crew members wearing Hawaiian shirts (similar to the photo of the Icarus II crew members, who were wearing Santa hats).The similar photos of the two crews hint that what kept the Icarus I from accomplishing its mission is what is happening to the crew of the Icarus II.