NASA's Return to the Moon

NASA’s Return to the Moon

BY EDWARD S. GOLDSTEIN Images courtesy of NASA

The last time we sent men to the Moon and returned them safely to Earth – back then, our astronaut corps’ makeup dictated only men would undertake these journeys – we left much unfinished exploration business undone.

During the Apollo era, NASA contracted for 15 flight-worthy massive Saturn V launch vehicles. Apollo 11 achieved the first landing with the sixth Saturn V, leaving nine for follow-on landings, three beyond the six missions that were attempted. Had budget cuts not crimped NASA’s plans, we would have mounted the Apollo 18, 19, and 20 missions with the likely landing sites Schroter’s Valley, the Hyginus rille region and Copernicus crater, all in the Moon’s equatorial region, as were the six landings.

An artist’s conception of the next generation of astronauts on the lunar surface. A new, larger manned lunar lander stands in the background.

Now, NASA intends through its Artemis program to land the first woman and the next man near the Moon’s south pole by 2024, initially aiming for a brief visit to the lunar surface leading up to six-and-a-halfday missions, roughly twice the length of the longest Apollo sortie, and subsequently establishing a sustained human presence by 2028. Going back to the Moon has seriously been proposed twice before, by President George H.W. Bush (1989 “Space Exploration Initiative”) and President George W. Bush (2004 “Vision for Space Exploration”) administrations, but failed due to a lack of capability and long-term national commitment. Why might this time be different?

Dr. John Logsdon, the George Washington University space historian whose books have chronicled the space policies of Presidents John F. Kennedy, Richard Nixon, and Ronald Reagan, has a notion why. “I think the fact that we in Apollo used up the easiest exploration destination very early on in the development of the program has led us over the past 50 years to try to re-create the rationales that led us to go to the Moon in the first place: power, prestige, very little science, and now economics,” he said. “They haven’t worked over this half-century since the end of Apollo. We in the U.S. have been aiming in my mind to go back to the Moon since 2004, pretty much consistently. We’ve been building hardware with the SLS [Space Launch System] and Orion [Orion Multi-purpose Crew Exploration Vehicle] ever so slowly, but there is a trajectory to get back to the Moon due to a combination of factors. One, I think, is the very simple reason that it is time to go back. If we are going to have a human spaceflight program, it should go somewhere, not just go around in circles. And the hope is we can finish the exploration of the Moon and find that there are economically valuable resources there, either valuable in terms of future space exploration, and maybe even [back] on Earth. We are not racing anybody; the race has been won. It is an attempt to re-create some of the factors that made Apollo sustainable, not only possible, but sustainable in a very different situation.”

An artist’s conception of the Orion command and service modules in lunar orbit.

Following the Water

Logsdon’s point about lunar resources may be the key to the current drive toward the Moon. We left there in 1972, largely believing that the Moon lacked the abundant, available, and extractable resources needed to sustain lengthy human exploration activity. What changed our perception were subsequent unmanned satellite missions that investigated previously unexplored lunar regions. And in a new refrain upon the famous mid-19th century rallying cry, the belief these days is, “There is water in them thar craters.”

In 1994, the joint NASA-Strategic Defense Initiative Organization Clementine mission used an eliptical polar orbit of the lunar surface to document for the first time the enormous south pole-Aitken impact basin, a hole in the Moon 1,616 miles across and more than 8 miles deep. Clementine’s sensors provided a tantalizing hint that permanently dark areas near the Moon’s south pole may contain frozen water deposited over millions of years by impacting comets. NASA’s Lunar Prospector mission, conducted 1998-1999, ended when the mission’s orbiter was deliberately crashed into a permanently shadowed area of the Shoemaker crater near the lunar south pole, after the presence of water ice was detected. NASA’s followon Lunar Reconnaissance Orbiter (LRO) mission, which involved directly observing a plume of material created by the impact in the Moon’s southern hemisphere Cabeus crater by the Lunar CRater Observation and Sensing Satellite (LCROSS) and a companion rocket stage, helped identify sites close to potential resources with high scientific value, favorable terrain, and the environment necessary for safe future robotic and human lunar missions.

NASA has selected three commercial Moon landing service providers that will deliver science and technology payloads under Commercial Lunar Payload Services (CLPS) as part of the Artemis program. Each commercial lander will carry NASA-provided payloads that will conduct science investigations and demonstrate advanced technologies on the lunar surface, paving the way for NASA astronauts to land on the lunar surface by 2024.

As a result of the LRO/LCROSS missions, “NASA has convincingly confirmed the presence of water ice and characterized its patchy distribution in permanently shadowed regions of the Moon,” said Michael Wargo, then NASA’s chief lunar scientist.

Added LCROSS project scientist and principal investigator Anthony Colaprete, “Seeing mostly pure water ice grains in the plume means water ice was somehow delivered to the Moon in the past, or chemical processes have been causing ice to accumulate in large quantities. Also, the diversity and abundance of certain materials called volatiles in the plume suggest a variety of sources, like comets and asteroids, and an active water cycle within the lunar shadows.”

If there are sufficient quantities of easily recoverable water ice near the Moon’s surface – and it should be noted the details of this proposition remain a big if, with great uncertainty about how much water there is beyond a foot deep below the Moon’s surface – that could be a massive driver for lunar and beyond lunar exploration in the remainder of the 21st century. “If we can get water at the poles of the Moon, you can split water into oxygen and hydrogen and make rocket fuel,” said John Thornton, the CEO of Astrobotics, one of the many commercial space companies seeking to be players in renewed lunar exploration, and which was selected by NASA in May to deliver precursor science and technology payloads to Lacus Mortis crater as part of the Artemis program. “So conceivably the Moon could become a refueling station for spacecraft to go out and refuel and go farther out into the solar system, or maybe just to explore the Moon more thoroughly.” He added, “We know water is there and there are various estimates as to how much water is actually there. In order to determine how much, we need a ground proofing experiment on the Moon’s surface.”

As Logsdon points out, the interest of the commercial space companies is vital to NASA’s current ambitions. “I don’t think there is enough political will to pay to go back to the Moon as a unilateral effort of the U.S. government,” he said. “By default, you are going to have to find partners if the U.S. government wants to do this. I hope it is not an illusion, but the impression [is] that the private sector for its own reasons is interested in going to the Moon, not as a government contractor, but by investing some of their own resources. I think that’s still to be demonstrated, whether the billionaires – the Jeff Bezoses and the Elon Musks – will put significant amounts of their own money into a Moon program. Clearly, other countries are interested in exploring the solar system starting with the Moon, realizing there is no way they can afford it on their own, so the only way to do it is by partnering with a major country, and I think the partner of choice despite all our foibles is the United States.”

Another factor to consider is that the costs of access to space are going down. “I think the big difference between now and a while ago is the technology has advanced considerably and the cost has come down considerably,” noted Thornton. “Now it is possible to buy many of the components we need for a lunar lander off the shelf. They are accessible and ready and the advent of very affordable commercial launch has made the Moon and space more accessible.” And then there is the challenge of using human ingenuity to do something new. “If we are to become true explorers as we once were when we crossed the oceans, and not rely on the resources of Earth, our ability to use the resources on the land is when we can become untethered from Earth and go really, really deep,” said Thornton. Some of the key components are creating fuel, finding sources of water, methane, or other volatiles that you can turn into fuel. Another key one is making parts off the world – such as with 3D printing to build habitats and solar panels generating vast quantities of power – and learning how to deal with the radiation environment.”

An artist’s conception of a manned ascent vehicle separating from a descent vehicle and departing the lunar surface. NASA will seek proposals from industry in support of rapid development of an integrated human lunar landing system, including elements such as a descent element, ascent element, and transfer vehicle.

Indeed, the commercial potential of space is a big driver for the Trump administration, whose Dec. 11, 2017 Space Policy Directive 1 switched course from the president’s reported desire to have NASA achieve the goal of landing humans on Mars by the end of his potential second term, to the charge that NASA “Lead an innovative and sustainable program of exploration with commercial and international partners to enable human expansion across the solar system and to bring back to Earth new knowledge and opportunities. Beginning with missions beyond low-Earth orbit, the United States will lead the return of humans to the Moon for long-term exploration and utilization, followed by human missions to Mars and other destinations.”

Following the directive’s issuance, NASA planned for a 2028 Moon landing that would be abetted by a waystation in a stable eliptical lunar orbit called the “Lunar Gateway.” The Gateway is expected to contain a small habitation module that the Orion crew module could dock with after launching from Earth on the SLS or other commercial launcher, and a power and propulsion element. From the Gateway, a lunar lander will descend to a lower orbit and then touch down and ascend from the Moon’s surface. In May, NASA selected Maxar Technologies to receive a $375 million contract to build Gateway’s power and propulsion element with a launch date of 2022 and flight demonstration lasting as long as one year.

Since Space Directive 1 was issued, the administration’s impatience with NASA’s initial 2028 schedule led Vice President Mike Pence, in his role as chairman of the National Space Council, to push in March for the new landing goal of 2024, raising eyebrows with his critique of the SLS’s slow pace of development, hinting at a possible turn to commercial launch providers. But when the administration announced the Artemis program in May, the $1.6 billion funding boost it asked lawmakers to provide NASA in fiscal year 2020 still contained additional funds for SLS development, along with $1 billion targeted for the lunar landers. Because NASA will not have enough core SLS systems, commercial launch vehicles will be required to get the landers to the Lunar Gateway.

Planning for Renewed Surface Operations

NASA is now gearing up for the accelerated schedule with an increased sense of urgency. “We are going to return humans near the Moon on Orion with a mission to go around the Moon coming up shortly in early 2020,” noted Dr. Greg Chavers, the Marshall Space Flight Center formulation lead for the Human Landing System. Chavers added, “Our sequence is first orbiting the Moon, getting humans to the Lunar Gateway and they will get in the lander at the Gateway and go from there to the surface. After the first landing mission we plan for missions in 2025, 2026, 2027, and 2028, one each year, building capability through the whole decade up to some kind of habitation or pressurized mobility system sometime in the late 2020s.” Chavers said the details haven’t yet been worked out as to whether the Gateway itself will be a refueling depot or the landers will be fueled near the Gateway, “but the end goal is to have the lander to be refueled and parked at the Gateway waiting for the crews to come back each year as they use the system to go to the surface.”

Like the International Space Station (ISS) the Lunar Gateway will be an international cooperative program.

Potential landing sites are in the vicinity of Shackleton crater, an impact crater whose peaks along its rim are exposed to almost continual sunlight, while the interior has not seen sunlight for more than 3 billion years. “The goal is to get to a site that has a lot of light, so we can follow up with missions for those stations, where you have lunar resources, where you would have access to solar power, even before the astronauts get there and after they leave, and you come back for the next mission,” said Chavers. He noted that after the first mission conducted totally in sunlight, follow up missions will require the development of technology “to allow humans to stay through the [10-plus hours] eclipse of the local terrain to make it more survivable at night. That will require systems on the surface to provide power for the crew.”

An artist’s concepton of the Lunar Gateway. The Lunar Gateway is envisioned as a waystation in orbit around the Moon, from which astronauts will travel down to the lunar surface and return. It will also be a jumping-off point for missions heading farther out in the solar system, such as to Mars.

Chavers said the second major consideration in a landing site “is to set up near a location where there are lots of volatiles, potential water ice that may be in a permanently shadowed region. We don’t want to put the crew in a permanently shadowed region,” where the ambient termperature is 25 degrees Kelvin, 80 degrees colder than on Pluto. “We want the surface station to be set up near there.” Among the new capabilities NASA hopes to have on the Moon to assist the astronauts, said Chavers, are “unpressurized rovers that will allow astronauts to get several kilometers away from the landing site.” He adds the agency is looking into pressurized rovers as well, which “can be autonomous, allowing the crew to get out of the lander and into the pressurized rover and have more volume, living space, and roving capability. When the crew is not there, the pressurized rover can rove on the lunar surface and perform science experiments between crewed missions. It’s not something we will have for the initial sortie, but for some of the longer range missions.”

Another consideration is the spacesuits the astronauts will use. Chavers noted suits already in development need to be tweaked with reduced mass and more flexibility in the lower torso. “On Apollo, the astronauts hopped, but we don’t want to go back and hop.” He added, “We are driving toward suits that can be reused and be long duration as well.” The lunar suits will first be tested on the International Space Station.

The Science Imperative

Science was not the primary rationale for the first voyages to the Moon, nor will it be for our return to the Moon. But to space veterans like Dr. James Garvin, chief scientist at NASA’s Goddard Space Flight Center, we may be vastly underestimating the Moon’s scientific value.

“The idea that the Moon is ‘been there, done that’ is as crazy as saying six one-tothree-day field trips to Africa is going to tell you the history of the planet Earth,” said Garvin. “It’s that dumb. If you are optimizing only one target, the Moon would be a fantastic place to go. We’re not done.”

Garvin added, “The Moon is Mother Nature’s best naturally controlled experiment that’s both accessible and meaningful to all of us here on Earth, and of course, inextricably linked to Earth’s history, the motion of the oceans, and even to some, the history of life. The Moon offers us the only really accessible laboratory to look at all the processes that affect solid planets, the rocky planets particularly, but also the rocky icy outer planetary satellites, all in one place.”

What makes the Moon unique, stated Garvin, is what it is not. “If you could design a world that is a laboratory for studying phenomena, the Moon is great because it is not complicated by mass gushings of water and oceans, complications by all kinds of life processes, and massive tectonics in the outer crust the way our Earth works. All of that stuff on the Moon is simplified. And it is a planetoid where there is a water cycle, a very different one from Earth; it’s the kind you’d expect on a small body, main-belt asteroids or otherwise. You can study what’s out there by going to the Moon.”

Whatever we learn about water on the Moon, said Garvin, could be profound. “It could be 2-to 3-billion-year-old water ice particles. Those are little time capsules of part of the solar system’s history that we aren’t going to be able to find anywhere else. If we find it in places that is more prevalent than not, and we protect it and store it and study it before we bring it home, that could be huge for science. We don’t have the old ice here on Earth. It’s all been recycled. And on Mars, there may be some insulated, deep [water], but most of it is in the modern cycle. So the Moon may be a way of getting some of the oldest water in our solar system, which would be incredibly valuable scientifically to understand how everything works.”

There are also implications for the science of astrobiology. “On the Moon, you can ask questions about the astrobiology of deep space without having to worry about mucking up what might be an extant biological system, as we could have on

Mars or in the oceans of Europa,” said Garvin. “Going to the Moon, we can bring testbed biology experiments with us and watch them react to deep space, evaluate how they react, test them in the Lunar Gateway or Space Station, wherever. And of course, the far side of the Moon can be an exquisite location for radio astronomy undisturbed by all the ‘noise’ our modern civilization generates.”

Onward to Mars

Of course, looming in the background of any discussion about returning to the Moon is what that will mean for the holy grail of human space exploration: Mars. “The Moon means everything when it comes to exploring Mars,” asserted Garvin. “While we all want to leap to Mars more than anything, that’s a big leap. Great leaps are super. People are good at them. But to have confidence in the engineering solutions that let us send women and men to places that are not close by, that are in a non human-friendly environment, we need practice. I really believe that. So the trick is going to be to open the lunar frontier. Use it. Learn from it and then do Mars.”

An artist’s conception of the Orion spacecraft configured for deep space missions, such as to Mars, as shown in this image.

For those of us who were among the estimated 600 million people on Earth who watched Neil Armstrong and Buzz Aldrin take humankind’s first steps on the Moon, it can seem excruciatingly frustrating that we may not live to see the first explorers set foot on Mars. But if the planners of the next lunar adventure are on the mark, the sequel to the Moon, episode 1, may be rewarding in its own right.