NASA Chief Scientist Waleed Abdalati recently visited our lunar simulation laboratory at the University of Colorado at Boulder, where students are investigating next-generation materials to be deployed as sensors on the Moon’s surface. Following the tour, Dr. Abdalati, who was director of the university’s Earth Science and Observation Center before moving on to NASA in January, asked the intriguing question, “What would you do next to move NASA’s human exploration forward beyond LEO [low Earth orbit]?” We believe that journeys outside the near-Earth environs should begin to advance the U.S. space program beyond the artificial separation between science and human exploration and instead build on this symbiotic relationship. By necessity, exploration of surfaces must involve geology, engineering science, chemistry, physics and astronomy.
There are some intriguing opportunities that could allow NASA to begin these joint science and human explorations during this decade using rockets and capsules already in development. One particularly exciting and innovative scenario uses the Orion Multi-Purpose Crew Vehicle for pioneering explorations of the Moon’s hemisphere that faces away from Earth, known as the lunar farside. Orion could be launched this decade on a human-rated rocket to carry a crew of four to the Moon-Earth second Lagrange point (which balances Earth and lunar gravitational forces), a location where Orion “hovers” above the farside but with Earth also in direct line of sight. This would be a first, placing humans farther than they have ever traveled from our home world (15 percent more distant than the Moon).
Preceding the Orion launch, an unmanned lander and rover would be sent to the Moon, touching down in the South Pole-Aitken Basin, one of deepest, oldest and largest impact basins in the inner solar system — a top priority for scientific investigation in the recent National Research Council (NRC) Planetary Sciences Decadal Survey. The scientist-astronauts would teleoperate the rover from Orion, gaining much-needed experience in human-assisted robotic geological exploration that will be required for missions to asteroids and to Mars. The rover would also deploy the first low frequency radio array on the radio-quiet farside; it would answer two of the top priority questions of the NRC Astrophysics Decadal Survey: “What were the first objects to light up the universe, and when did they do it?” The samples gathered by the rover would be launched back above the Moon where Orion would rendezvous with this payload. Thus, on this first mission beyond LEO in over 40 years and the first human/robot exploration of the lunar farside, astronauts would return with a treasure trove of the oldest known rock samples that may hold the key to understanding the Earth-Moon formation.
A subsequent Orion mission could involve an Apollo-style sortie to the lunar surface using an affordable two-person lander, possibly developed and deployed with international collaboration. But didn’t we already do this in the 1960s? The difference is that new, remote-sensing observations of the Moon by spacecraft such as NASA’s Lunar Reconnaissance Orbiter (LRO) have revealed much more interesting and scientifically valuable locations to explore. For example, LRO recently found a lava tube at the bottom of a lunar crater. Astronauts could land in this crater and explore, using a human/robot tandem, geological features never before seen on an extraterrestrial body. Ancient lunar volcanism is important to understanding both the Earth’s and the Moon’s evolution. Equally valuable is that these lava tubes would be ideal sites to house and shield astronauts from solar and galactic radiation while they learn to live and work on another nearby world before much longer and more dangerous missions to asteroids and to Mars. Imagine real-time, high-definition video coming back to Earth as the astronauts explore these dark, expansive caverns cut millions of years ago by flowing volcanic magma. This is the ultimate in reality television!
Another intriguing and important location for a sortie mission would be the lunar poles, where permanently shadowed craters are now known to house substantial amounts of water ice. Exploring these craters, which are possibly the coldest regions in the solar system, with robots and learning how to mine water ice would be firsts in the space program.
With the valuable lessons learned from these orbit and surface explorations of the Moon, we might begin to move more sure-footedly into the solar system. Using these lunar missions, we would hope to learn more about the space radiation environment beyond LEO and develop and test shielding for spacecraft that will be a prerequisite for venturing beyond the Moon. The next missions could involve longer, six- to nine-month operations to near-Earth objects, such as the recently discovered trojan asteroids that share Earth’s orbit. Not only would such a mission allow significant scientific research but it also would validate the technologies and techniques required when approaching the moons of Mars and other planets. Then, with risks reduced, a human orbital mission around Mars may be possible.
This steppingstone approach to human exploration of the solar system, beginning with the Moon-Earth environment, is safe but also extremely interesting from a science perspective. Joint science and human explorations, making use of new capabilities for telerobotics, are an exciting vision for NASA’s near future.
Jack Burns is a professor and vice president emeritus at the University of Colorado, Boulder; he also directs the NASA Lunar Science Institute’s Lunar University Network for Astrophysics Research (LUNAR) center. Scott D. Norris is a sitting member of the LUNAR steering committee and a senior manager for independent research and development at Lockheed Martin Space Systems’ Human Space Flight line of business.
