in the boost phase. Against a short-range rocket, this period would be too short for a pebble to reach it. To make it effective in this "Protection Against Limited missile Strikes" concept, or PALS, the pebbles should be able to continue tracking the missiles after their motors had burned out. This would either require a dramatic increase in the capability of the pebble's seekers, or require a network of low-orbit satellites to provide this same information. Following Cooper's lead, Monahan began the Mid-and-Terminal Tiers Review (MATTR) in early 1990. Before this was complete, Cooper was appointed as the director of the SDIO on 10 July 1990, and Monahan retired. Within SDIO at least, PALS was now the mainline concept. In order to fill the need for a ground-based interceptor to back up the pebbles, the Army began development of the High Endoatmospheric Defense Interceptor (HEDI), essentially a short-range, mobile version of ERIS. A new lightweight interceptor, LEAP, would arm both ERIS and the Navy's Standard Missile. As work continued, the Gulf War broke out and Cooper's scenario of United States troops being attacked by short range missiles came true; the nightly news carried vivid images of Scud missiles being attacked by Patriot missiles. Bush praised Patriot, claiming that 42 launches had resulted in 41 intercepts. Congress, formerly skeptical of SDI, suddenly had a very different opinion of the matter, especially with the realignment of the concept towards the PALS concept which would have been helping deal with missiles like Scud. On 29 January 1991, Bush used the State of the Union speech to announce that SDI was being refocussed to the new "Global PALS", or GPALS, concept: This change in posture meant the system no longer had to deal with a large-scale attack, only small ones. Once again the number of pebbles was reduced, this time to between 750 and 1,000. Missile Defense Act of 1991 The new GPALS concept was fully described in a May 1991 report published by the SDIO. It consisted of four parts: a ground-based missile system to protect the United States, a ground- and sea-based system to defend overseas United States forces and allies, Brilliant Pebbles in space, and a command and control system tying them all together. Brilliant Pebbles was seen as both a system for providing early detection of launches, as well as being able to attack any missile with a range greater