The computers in the next-generation shuttles have also been entirely revamped. To reduce the huge workforce needed to monitor every tiny event in the mission on the ground, each instrument that measures temperature, pressure, strain or vibration, among other things, in SLI vehicles has its own built-in computer, which doubles as a node on a network extending throughout the RLV. This network is made up of expert systems. These programs can constantly read signals from each computer on the network, isolate problems in real time and predict failures. Coupled with escape systems that today's shuttle lacks, the computers could possibly save the lives of the crew during an accident by signaling when to bail out or even by separating a crew capsule from other parts of the RLV that are in danger. "There are three levels to safety," says Doug Young, Northrop Grumman's space systems director. "The first is to make the vehicle more reliable. The second is to provide the crew with an escape system and the third is to make sure that the crew knows when to get out."
In perhaps the greatest break with the shuttle, the new launcher and orbiter designs are much more appropriately scaled to NASA's real needs—that is, for a slimmed-down and, at times, unmanned reusable launch vehicle. The current shuttle has rarely approached its full payload capacity and often a crew isn't required. SLI concepts contain a smaller orbiter that travels without a crew if the on-board task—such as putting a satellite into orbit or conducting a science experiment remotely—can be automated.
It's the Accounting, Stupid
Whether NASA ever replaces the shuttle with a new vehicle will depend on the agency's ability to improve its woeful budgeting skills. In a report on SLI issued last September, the congressional General Accounting Office chastised NASA for lacking any modern financial controls. It's no surprise, then, that NASA cancelled the shuttle-replacement program not necessarily because it was too expensive but because the agency really had no idea what it would cost. "SLI was deceptively simple," says Kevin Neifert, director for advanced space and launch systems at Boeing's Phantom Works, "but there were very aggressive goals around safety and reliability
and operating costs."
In proposing a shuttle replacement, NASA circumvented a basic rule of business school: "Quality, speed and cost—choose two." Under NASA's benchmarks for the program, which anticipated a new spacecraft within a decade, the agency wanted to guarantee that a crew would not be lost more than once in 10,000 flights—40 to 70 times better than the shuttle's projected performance and 180 times better than what the shuttle has so far achieved. The agency requested an operating cost of only $500 million annually for a fleet of three or four vehicles launching every few weeks. That would be about the price of a single shuttle flight—a great idea but an impossible request. "Even a factor-of-two improvement in cost would be wonderful," said Antonio Elias, general manager for advanced programs at Orbital Sciences, before SLI was cut back. "If NASA could reduce its $3 billion a year [shuttle budget] to $1.5 billion, it would justify the cost" of a new reusable launch vehicle.