ANTIMATTER ROCKETS:
IF YOU'RE A SCIENCE FICTION FAN YOU KNOW THAT ANTIMATTER IS A FUEL OF CHOICE
FOR FUTURISTIC ROCKETS.  BUT IT'S NOT JUST FOR STAR TREK ANYMORE.  MANY
PHYSICISTS THINK NASA COULD USE ANTIMATTER TO POWER UP SPACE SHIPS IN REAL
LIFE.  GERALD SMITH AT PENNSYLVANIA STATE UNIVERSITY EXPLAINS JUST WHAT
ANTIMATTER IS.
     SMITH: "all fundamental particles have antiparticles. . .an antiparticle has the opposite electrical
charge as a particle.   however  all other features . . .are the same. "   ANOTHER BIG
DIFFERENCE: ANTIMATTER AND MATTER SELF-DESTRUCT WHEN THEY TOUCH EACH
OTHER. 
     "when an antiproton annihilates with a proton it release more energy per unit of pmass than any
other known interaction in nature."
     SMITH WANTS TO HARNESS THIS ENERGY TO POWER A SPACE SHIP.  BUT MAKING
ANTIMATTER ISN'T SO EASY.  IT'S DONE BY SMASHING ATOMS TOGETHER IN HIGH
POWERED ACCELERATORS, BUT YOU CAN'T EXACTLY BRING YOUR ACCELERATOR
ALONG FOR THE RIDE AS YOU FLY THROUGH THE SOLAR SYSTEM.  ON THE OTHER
HAND, MAKING ANTIMATTER ON EARTH AND PUMPING IT INTO YOUR FUEL TANK
WON'T WORK EITHER--REMEMBER, AS SOON AS THE ANTIMATTER TOUCHES THE SIDES
OF THE TANK, IT WILL SELF-DESTRUCT.  CURRENTLY, SAYS SMITH, SCIENTISTS CAN
KEEP A SINGLE ANTIPARTICLE INTACT BY SUPPORTING IT IN MID-AIR WITH MAGNETIC
WAVES.  NOW SMITH AND HIS COLLEAGUES WANT TO FIND A WAY TO TRAP THE
BILLIONS OF ANTIPARTICLES NEEDED TO POWER UP A ROCKET.  
     "That is the very catalyst that's going to make this program work or not work."
     THEY HAVE THEIR WORK CUT OUT FOR THEM, BUT IF THEY SUCCEED, SMITH
SAYS THEY COULD BUILD A ROCKET THAT WOULD TAKE ONLY 45 DAYS TO GET TO
MARS.