to determine if any damage occurs during flight. Upon landing, the vehicle's on-board computer could download the vehicle's health status to a ground controller's laptop computer, recommend specific maintenance points or tell the launch site it's ready for the next launch. Oxygen-air-breathing propulsion The Advanced Space Transportation Program is developing technologies for air-breathing rocket engines that could help make future space transportation like today's air travel. In late 1996, the Marshall Center began testing these radical rocket engines. Powered by engines that "breathe" oxygen from the air, the spacecraft would be completely reusable, take off and land at airport runways, and be ready to fly again within days. An air-breathing engine – or rocket-based, combined cycle engine – gets its initial take-off power from specially designed rockets, called air-augmented rockets, that boost performance about 15 percent over conventional rockets. When the vehicle's velocity reaches twice the speed of sound, the rockets are turned off and the engine relies totally on oxygen in the atmosphere to burn the fuel. Once the vehicle's speed increases to about 10 times the speed of sound, the engine converts to a conventional rocket-powered system to propel the vehicle into orbit. Testing of the engine continues at General Applied Sciences Laboratory facilities on Long Island, N.Y. Other advancements Along with air-breathing propulsion, there is also magnetic levitation, highly integrated airframe structures that morph in flight, and intelligent vehicle health management systems are some of the other technologies being considered for a third generation RLV. The ASTP is also investigating technologies for a fourth generation reusable launch vehicles that could be operational in the 2040 time-frame. The goal is to make space travel safer by a factor of 20,000 and more affordable by a factor of 1,000, compared to present day systems. Routine passenger space travel is envisioned for this fourth generation RLV. Accessible outer space As access to outer space improves and becomes routine, this will enable new markets to open up. This includes space-based adventure tourism and travel, along with space-based business parks. Other types of benefits to commerce and the global population includes solar electric power beamed from space to Earth, space-based hospitals for treatment of chronic pain and disabilities, mining asteroids for high-value minerals, and a worldwide, two-hour express package delivery system. Beyond Earth's orbit The ASTP is developing technologies to decrease the trip times and reduce the weight of the propulsion systems