Yesterday’s New York Times had an op-ed by planetary scientist Carolyn Porco about space exploration. Unlike many planetary scientists, who are skeptical at best about the Vision for Space Exploration out of concerns that the program will suck up more money from science programs, Porco is supportive of the effort. Much of that support stems from the belief that the development of a Saturn 5-class launch vehicle, the Ares 5, could pay dividends for robotic space exploration as well, enabling larger spacecraft and/or shorter travel times. “The termination of the Saturn V program also had a stifling effect on the robotic exploration of other planets. In essence, we lost the ability to deliver larger, and in some cases faster, payloads elsewhere in the solar system.”
This argument isn’t used often, although it’s not completely novel: at the AAAS conference in San Francisco this past weekend, NASA Ames director Pete Worden noted that the Ares 5 would enable the development of much larger space telescopes than can be launched today on existing vehicles. One factor that isn’t discussed, though, is just how cost-effective such an approach is. The Ares 5 is unlikely to be a cheap vehicle: each launch is likely going to cost several hundred million dollars, and perhaps up to a billion dollars each, depending on its flight rate and final design. Will space science missions be able to afford that expensive a launcher. Porco, in her op-ed, notes that reduced flight times could save money: “In space, as on Earth, time is money, and the money saved could have been spent elsewhere.” However, mission operations, particularly in cruise modes when there is little going on, is only a small fraction of overall mission costs. And missions that are so big that they need an Ares 5-class launcher will likely also be very expensive, and therefore difficult to fund. Is there really that big of an opportunity for alternative uses for Ares 5?