down into the $100,000 range, even the fully expanded system would cost $10 billion. Launch costs were not part of that estimate. If the empty weight was on the order of a few kilograms, then a single Space Shuttle could launch dozens, perhaps hundreds. They were so light that some consideration was given to launching them from the ground using a railgun. Such lightweight designs would have a limited "cone of action", carrying so little rocket propellant that they could only attack targets right in front of them. A larger interceptor with more propellant could attack more targets, so smaller numbers would be needed to provide coverage. In any event, launch costs would be greatly reduced compared to the baseline system that required hundreds of battle stations, each of which weighed and could only be launched one at a time. Starting the next year, Wood had the former Excalibur team begin a more detailed study. By the fall of 1987, he had blueprints of the proposed design, a physical model to show, and computer simulations of the system in action. He also came up with a clever play on the Smart Rocks name, calling the newer, smaller, smarter concept Brilliant Pebbles. In another clever turn of phrase, one skeptical congressman would later refer to them as "loose marbles". Pebbles becomes the Strategic Defense System With Teller's help, Wood was able to brief Abrahamson on the concept in October 1987. Abrahamson was impressed enough to visit Livermore to view the mockups and watch the animated simulation they had created. This led to increased funding for further studies of the concept. In March 1988, Teller and Wood were able to directly brief President Reagan on the concept, taking the model pebble with them and theatrically hiding it under a black cloth when reporters were allowed to take pictures. Teller reiterated that the price for the system would be on the order of $10 billion. In May 1988, Abrahamson initiated the Space Based Element Study in order to refine the design of SDS's Space Based Interceptor (SBI). As part of this study, he had Livermore's work considered as one of the interceptor concepts. This study agreed with the basic concept that all the required sensors could be placed on the missile. While this was going on, the United States Air Force Space Division began a similar study on the baseline Space Based Interceptor.