This is part of IEEE Spectrum's Special Report: Why Mars? Why Now?
You can’t take much into space. When a rocket is on the launchpad, 99.9 percent of the mass is the fuel and the vehicle itself. That leaves 0.1 percent for everything else—the crew and all their supplies. When considering what to bring, how do we trade off between consumables (needed for survival), spare parts (for safety), and research equipment (which gives the mission value)?
Starting in 2005, NASA asked my group at MIT to develop SpaceNet, software that helps mission planners evaluate these trade-offs. The program manages and models the complex supply chain of vehicles and supplies along with the processes and orbital dynamics required for manned missions, whether they’re to Mars, the International Space Station (ISS), or a lunar outpost. We designed our software to model each step in a mission as well as a whole campaign of missions. SpaceNet allows planners to quantitatively compare different mission architectures to optimize the exploration capability and launch mass. We also want to make supply chains robust so that one failed or delayed mission doesn’t ruin the whole plan.
In 2005, we tested our computer models by participating in the Haughton-Mars Project, in which a small group of researchers live in an Arctic base as if they were on Mars. The experience was enlightening. We found that of the operational inventory (that 0.1 percent of launch mass), two-thirds went to ground vehicles and fuel for powering the base. From this experience, we’ve calculated that each crew member added to a 600-day Mars mission would require sending 13 metric tons more cargo to the Martian surface.
But even if you deliver the right amount of supplies, it matters how they are organized. For example, there are between 15 000 and 20 000 objects on the ISS. If you take the total number of useful crew hours in a year and divide by the total operating budget, you find that the value of 1 hour of an astronaut’s time on the ISS is US $186 000. So 5 minutes spent looking for one hard-to-find item wastes $15 000.
On a Mars mission, time will be even more valuable. Storage should be reconfigurable so that the most needed items are always accessible and everything else is out of the way. We’re now working on an RFID system that tracks the location of each piece of inventory at all times. The ultimate goal is to create smart, self-aware environments that are both safe and effective for exploration far from Earth. We hope that better space logistics will give future astronauts more time to do valuable work.
—As told to Joshua J. Romero
For more articles, go to Special Report: Why Mars? Why Now?
About the Author
Olivier L. de Weck is the leader of the MIT Strategic Engineering Research Group.