In the latest of new ideas for sending humans to the moon and beyond, John Shannon, NASA’s shuttle program manager, made his pitch to the Augustine panel: to use the space shuttle system’s orange fuel tank and twin solid-rocket boosters, but instead of carrying the shuttle, it would lift a cargo container, and the Orion capsule.
The panel, which is charged with reviewing the future of U.S. human spaceflight, has already heard numerous alternative ideas from private companies arguing that their launch vehicles would be cheaper and more reliable than the Ares rockets currently being developed by NASA as the successor to the space shuttle. The rockets are part of the Constellation program which outlines plans to send humans back to the moon by 2020, and then to Mars and beyond, but have been highly criticized for being too costly and behind schedule.
According to the Associated Press, Shannon says his idea is not a break from NASA and that he likes the current design for returning to the moon, but he worries that the cost will be an issue. “I don’t care what launcher we use, I just want to go to the moon.”
Shannon’s plan, called the Shuttle-Derived Heavy Lift Launch Vehicle, would save money and time by using already existing hardware like the shuttle’s engine and boosters, and flight software and avionics. It would also use the existing launch pad structures at Kennedy Space Center and launch and ground control software, and thus could launch a year earlier than Ares.
The plan would use the same new Orion crew capsule being designed for Constellation, but require building a large cargo container. The drawback is that the vehicle would not be as powerful as the Ares rockets and could not carry as many astronauts. (View the PDF of Shannon’s presentation, which includes the technical details.)
Shannon’s idea was well received by the panel. According to the Associated Press, Norman Augustine, the panel chairman, says the presentation was “terrific, very well done.”
However, Shannon is not the only one to have thought of a shuttle-derived launch vehicle, and his idea actually builds on the U.S. government’s original concept called the Shuttle-C, a launch vehicle concept researched and partially developed from 1984 to 1995 to replace the space shuttle. It called for using a unmanned cargo carrier in place of the orbiter, was compatible with existing shuttle infrastructure, and would also be a heavy-lifter. But neither NASA or the Department of Defense, who were sharing the costs, committed to the project and it eventually scraped.
In addition, when the Soviet Union lost the race to the moon with America, it decided to build its own vehicle for space travel, one that could allow it to eventually colonize the moon and travel to Mars. Called the Energia-Buran Reusable Space System (MKS), it used a manned vehicle that was aerodynamically just like the shuttle and carried a cargo container, but because of lack of engineering experience used parallel liquid propellant boosters, and a different engine. Like Shannon’s design, the launcher had to distinct roles: it could be used as either a vehicle to carry just cargo or an orbiter to take manned missions to space. It had two successful flights between 1987 and 1988, but was terminated in 1993.
Yet, there are important technical concerns with Shannon’s design to consider. One of the main criteria for the shuttle’s successor is to improve the safety and reliability of the vehicle. The shuttle’s external fuel tank is known to shed material causing damage to other parts of the vehicle, particularly to the critical heat shield, or thermal protection system. In addition, it is safer to have the crew as far away from the fuel, a source of combustion, as possible–the reason Ares engineers have designed the crew on top, propellant on bottom. Plus, the old parts would eventually have to be replaced, so do we spend the money for something new now or later?
The committee’s report, which is critical to NASA’s future, isn’t due until the end of August, in the meantime NASA will continue building the Ares rockets.