By Ahmad A. Malik
When Apollo 11 landed in Mare Tranquillitatis in July 1969, Neil Armstrong and Buzz Aldrin left the lunar module and conducted the first ever extra-vehicular activity—EVA in NASA parlance—on the surface of the Moon. They spent two and a half hours collecting 47 pounds of moon rocks to bring back to Earth.
Armstrong and Aldrin may have made their spacewalk look almost routine to viewers 238,900 miles away, and the samples they collected may have seemed random. But the excursion was actually a carefully choreographed scientific exercise that required months of preparation and research to determine which samples the astronauts should bring back.
A similar challenge was the mission of the RIS4E field crew team in Hawaii, and it’s why NASA sent an active astronaut, Rick Mastracchio, along with field volcanologist Dean Eppler and planetary geologist Debra Hurwitz to envision and simulate an EVA on Mars.
Using the geological instruments from four field teams on the RIS4E study, the crew team aims to marry the science and instrumentation into a deliverable plan for future astronauts on planetary surfaces. Their focus is on efficiency—improving the procedures used by the Apollo astronauts in analyzing and collecting samples.
“When you’re a field geologist, the thing you’re interested in is called geologic mapping,” said Eppler, the crew team leader, who is based at NASA’s Johnson Space Flight Center in Houston. In other words: “Where are the rocks?”
The crew team used a suite of tools designed by geologists at NASA’s Goddard Space Flight Center in Maryland and at Stony Brook University in New York, which include X-ray diffraction, X-ray fluorescence, thermal imaging, and radiometry carefully designed to map out the topography of landscapes for the field team in real time.
“My role in this particular excursion is a crew member, basically functioning as an astronaut exploring the surface of another planet,” said Hurwitz, a self-funded participant in the field study who works at Johnson Space Flight Center. “We are trying to figure out how to best use instruments to analyze rocks in situ”—in their original place—“and get as much geochemistry information as we can, so we can change how we analyze the rocks in the field and collect the right samples.”
The purpose of the whole field team is not only to test the instruments, but also to determine whether or not they can provide actionable information to the astronauts and scientists.
“The question comes down to: do I need it, does it make my job easier, does it inform me?” Eppler said. “Or does it make my job harder and provide me with information I don’t need in the field? Those are the kinds of questions that are going around, but none of those questions have been evaluated – until now.”
Careful thought goes into what samples astronauts will return from these planetary surfaces. In Apollo 11, the astronauts wound up with cargo space to spare—more than the mission planners anticipated—so Armstrong decided to bag as many lunar rock samples as he could, rather than waste the space on the trip home. A key goal of RIS4E is maximizing the efficiency of exploration.
“If you want to go on a vacation and you have an SUV of a certain volume and a certain carrying capacity, you can’t put a grand piano there, no matter how much you like to practice on vacation – it just isn’t going with you,” Eppler said. “By the same token, going to a planet and coming back, you’re constrained in how much you can bring and bring back, and anything we can do to manage that in an intelligent fashion gets you where you want to go.”
In the field, the crew simulated experiments with the four instrument teams, managing and budgeting their time as if they were on another planet. Because Mastracchio and his crewmates aren’t trained to use the instruments, they would announce they were “leaving the rover,” start the timer and call on each instrument team to take their measurements or conduct their experiments. “Houston, I’m going out for an EVA. You let us know if you have a problem with that,” Mastracchio joked at one point.
The crew also collected samples they deemed worthy to return to the laboratory. After the four teams concluded their experiments, the crew headed back to the imaginary rover and the timer stopped.
So what did they learn after several days in the field?
“One of the major findings we had is that some of these instruments were really good for field use, and some of them are not so good for field use,” said Eppler. “Some were very utilitarian in the field. While I wouldn’t want to drag [large instruments] around and set them up, they’re obviously something you’d want to put on the top of a rover. But also, that doesn’t mean they’re not useful in a laboratory setting.”
The other finding: “Two crew members are better than one, and three are even better.”