Science News: Small satellites called CubeSats are cheap to build and easy to launch, but they have one big problem. They can either move fast or move far, not both. Small satellites called CubeSats are cheap to build and easy to launch, but they have one big problem. They can either move fast or move far, not both, because chemical thrusters and electric thrusters need different fuels. Now, engineers at MIT have... [5189 chars]