Copyright © by Douglas W. Gage. Published by the Mars Society with permission
PREPARE NOW FOR THE LONG STAY ON MARS
Douglas W. Gage
The long pole challenges for the human exploration of Mars lie in developing the systems, practices, and procedures necessary to support human life and productive activity on the surface of Mars itself for extended periods of time, not in getting humans there and back.
Accepting the basic parameters of Mars Direct and its multifarious Design Reference Mission derivatives, namely near-Hohman transfer orbits, pre-emplacement of assets, and ISRU exploiting (at least) atmospheric CO2, it is clear that humans will spend more time on the surface (nominally 18 months) than in transit to and from Mars (6-7 months each way).
On a per-day basis, an astronaut must and will in fact be significantly safer while on the surface of Mars than while in space – beyond the intrinsic advantages of being on a stable surface with significant gravity and with none of the risks associated with launch and (re)entry, it is feasible, cost-effective, and imperative to reduce surface stay risk through extensive careful planning and preparation, and the commitment of extensive support equipment and supply resources to the enterprise.
It follows that the cost effective exploration program strategy is for fewer crews each staying longer, rather than mimicking the Apollo sequence-of-sorties model. The first stay should be planned as a long stay of 8-10 years on the surface, not just 18 months. A second crew would join the first at the outpost 26 months later. The earth return vehicle need not be pre-emplaced – it can be sent 4-6 years after the first crew has arrived, and return vehicle systems can be tested in an initial unmanned multi-tonne sample return.
The Apollo/Saturn lunar transportation system was developed via an intensive (and expensive) program in less than a decade. Zubrin has argued persuasively that a Mars transportation system must similarly be developed quickly and intensively. But this is not the way to handle the stay on the Martian surface.
A long-term development program comprised of many fairly-independent low-level efforts is needed to effectively exploit numerous technologies and strategies including ISRU, recycling, and automation in order to provide needed shelter (underground, constructed by robots), power generation (nuclear) and distribution, habitat atmosphere and thermal control (active and passive), communications (on Mars and to Earth), transportation (manned and unmanned, ground, airplane, and balloon), food (what to bring, what to grow, what to make), healthcare, and everything else. The validation of systems and procedures will require many years of testing which can be most effectively and cost-effectively done on earth (not on the moon). Many of the capabilities developed by this program will provide direct payoffs on Earth well before humans set foot on Mars.
The critical challenges to this effort will be political and administrative, not technical: how to coordinate a small (compared with rocket development) program, one whose budget would not ordinarily warrant high-level attention, across multiple agencies (NASA, plus DOE and likely DOD, NSF, NOAA) and over a period of decades.
Douglas W. Gage is a retired DARPA program manager and now serves as an independent consultant based in Arlington, VA.