Technology

Fly me to the Moon… a case for manned lunar exploration

The Moon has forever been one of the most fascinating celestial bodies to be observed by all civilisations. It was also the first celestial body to be inspected in detail. When Galileo Galilei first applied a telescope to astronomical observations, he noted [1]: “It is a beautiful and delightful sight to behold the body of the Moon.” Indeed the beauty of the Moon can be seen in Figure 1. Galileo discovered a world much like ours, scattered by valleys, craters and ridges. Since the time of Galileo, mankind’s exploration of the moon has gone a long way. Nowadays, every amateur astronomer can observe the Moon in a greater detail than Galileo could imagine, and lunar orbiters have mapped nearly every square meter of the grey rocky surface of our nearest neighbour in space. Yet, mankind’s attempts at visiting this barren world have been scarce to say at least. Only 12 people, all from one nation, have set foot on the lunar surface. This ought to change, as the technology rapidly develops, and more and more nations are looking forward to restoring human presence on the lunar surface, with the prospect for long-term settlement.

Figure 1: Photograph of the Moon through an amateur telescope. Multiple surface features such as craters and mare are visible. Credits: Karol Masztalerz

Previous lunar exploration

Modern, advanced lunar exploration can be divided into following types:

  1. Orbiters: spacecraft which orbit around the Moon at a constant altitude and observe it from distance
  2. Landers/rovers: robots which land on the lunar surface, and either explore it without moving (landers), or explore it by driving around (rovers)
  3. Manned missions: missions which include sending humans to lunar orbit, and lunar surface, possibly for long-term stays.

The first spacecraft to reach the Moon was Soviet Luna 1. The spacecraft is shown in Figure 2 below.

Figure 2: Replica of Luna 1 probe. Credits: RIA Novosti archive [4]

The extremely basic probe only swung-by the Moon. It flew-by the lunar surface at the distance of about 6000km, and returned a small handful of scientific data [2]. What derived from the Luna programme was a programme to launch lunar orbiters: spacecraft that would spend their time orbiting around the Moon, gathering photographs and other scientific readouts from a safe orbital distance. One of the most modern lunar orbiters is the Lunar Reconnaissance Orbiter, LRO, but even this advanced piece of machinery has severe limitations. LRO can only obtain photographs of the lunar surface with a resolution of 50cm [3], and it can not do any on-site research of, say, lunar rock samples.

One solution for lunar on-site research are lunar landers. In the early days of the space-race, the Soviet  Luna 9 spacecraft soft-landed on the lunar surface. It was a fairly basic lander, as it only contained 2 scientific instruments: a radiation sensor, and a camera. In the modern day, landers have become more advanced, and an example of this is the Chinese Chang’e 3 lander, which carried a plethora of research equipment to the lunar surface, including a rover named Yutu. A photograph of the lander is shown below in Figure 3:

Figure 3: Portion of Chang’e 3 lander on the lunar surface photographed by a camera on-board of the Yutu rover. Rover tracks are visible on the left side of the image. Credits: Chinese Academy of Sciences / Planetary Society [5]

The lander is a stable platform with multiple experiments aboard, and the rover is capable of exploring nearby lunar terrain. But the landers and rovers lack a few critical abilities needed for rapid exploration.

The human spirit:

Humans are inherently curious. Few of us have been to the Moon, but Gene Cernan, an Apollo astronaut who has visited the lunar surface, once said [6] “Curiosity is the essence of human existence and exploration has been a part of humankind for a long time.” This trait, curiosity, is what all rovers, landers and orbiters lack. Ofcourse, these research platforms provide plenty of data. But the largest chunks of data about the Moon were brought about when the American space programme landed Apollo astronauts on the lunar surface. Between 1969 and 1972, NASA has landed 12 humans on the Moon. Not only did these humans conduct pre-planned experiments and gathered samples, but also conducted real-time observations of things that would take months to be noticed by rovers. The longest time humans have spent on the Moon during a single mission was 3 days. In just 3 days astronauts were able to scout several square kilometers of land, gather samples, conduct experiments, and most importantly, be curious. Humans are able to quickly notice patterns and oddities. This is well evidenced by a piece of conversation between astronauts on the Apollo 15 mission [7]:

145:25:00 Schmitt: Okay, we’ve got a large boulder of very intensely fractured rock, right on the rim, right near the Rover.

[Jack is moving toward the boulder.]

145:25:14 Schmitt: It looks like a finely vesicular version of our clinopyroxene gabbro. It’s obviously crystalline and has generally that same appearance. There is, in one spot here, some inclusions of a darker gray rock also intensely fractured. The fracture systems, I think, will show up well in the flightline stereo.

Although this conversation features a lot of geological jargon, the main point is that in just 14 seconds the geologist Harrisson Schmitt is able to notice an interesting boulder, come up to it and investigate it, drawing conclusions about it’s structure. Schmitt and the mentioned boulder are shown in photograph in Figure 4 below.

Figure 4: Astronaut Harrisson Schmitt (left) investigating a large, fractured boulder on the lunar surface. Credits: NASA [8]

Such research of boulders with remotely-controlled rovers would take days (and a static lander would not even be able to approach the boulder), because a rover’s driving path towards the boulder must be carefully planned, and the drive is painfully slow. Tasks that are trivial to humans are extremely complex for robots. Human curiosity combined with our swiftness makes research very rapid, compared to clumsy robots. This is best evidenced by the fact that one of the most advanced lunar rovers to date, Chang’e 3 Yutu rover, has become stuck in the lunar soil after driving for just 115 meters [9]. For humans, a 115 meter walk is just a short stroll, with no larger issues. And even if an astronaut were somehow to get stuck, our dexterity makes it possible for us to stand up easily (as this has occurred numerous times during Apollo missions, when astronauts have tripped on the lunar surface).

Issues with putting humans on the Moon

Naturally, manned missions are more expensive: humans need life support systems, food, water, oxygen and living space. They must also be protected from radiation, vacuum and other dangers. This means that manned missions are harder and more expensive to conduct. Yet, nowadays is the perfect time to act. Humans have advanced technology that enables us to survive for long periods in space, as evidenced by the research aboard the International Space Station. Many technological challenges such as radiation protection and supply shortage stand in our way to conquering the Moon, but if mankind could land 12 people on the Moon more than 50 years ago, surely if all effort is put together, humans should be able to settle on the lunar surface in a permanent base, allowing for extensive, rapid exploration of our nearest neighbour.

Vague plans

Manned lunar missions have been announced and cancelled for many years.
From the cancellation of Apollo 18 and further Apollo missions, caused by political factors and loss of public interest, to constant delays in NASA Artemis programme, or unfulfilled promises of Roscosmos to establish lunar bases. Technology is obviously not a barrier: humanity has developed so far compared to what was available 50 years ago when Apollo missions have occured. Perhaps the problem is in our faulty human nature. We have lost the curiosity, the sudden, inexplicable need to explore and push our boundaries. We have replaced it with stagnacy and comfort. Quoting the famous astronomer, Carl Sagan, who once said [10]: “These days, there seems to be nowhere left to explore. Victims of their very success, the explorers now, pretty much, stay home. Maybe it’s a little early- maybe the time is not quite yet- but those other worlds, promising untold opportunities, beckon.” However, the time to explore and push boundaries of human understanding is now.

Summary

Now, more than ever, humanity is in the right place to put people on the Moon with a long-term presence. The scientific gains from long-term presence on the Moon are immeasurable, but include gaining experience needed to settle humans on Mars, rapid development of technology for spaceflight, massive economical boost and incentive to the private spaceflight sector, and plenty of lunar research that awaits the future astronauts. And the Moon is only the starting point to further exploration of our solar system. As Carl Sagan said [10], “Those other worlds, promising untold opportunities, beckon.”

This article has been written by Karol Masztalerz of the University of Manchester, Faculty of Science and Engineering, as a part of Science Embassy project.

References

[1] Galileo Galilei, The Starry Messenger, Venice 1610: “From Doubt to Astonishment”

[2] National Aeronautics and Space Administration. (2019). Luna 1. Retrieved October 20, 2020, from Nasa.gov website: https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1959-012A

[3] Robinson, M., Brylow, Tschimmel, Humm, Lawrence, Thomas, … Hiesinger, H. (2010). Lunar Reconnaissance Orbiter Camera (LROC) Instrument Overview. Space Sci Rev, 150, 81–124. https://doi.org/10.1007/s11214-010-9634-2

[4] RIA Novosti archive (n.d.), “Interplanetary station Luna 1”, retrieved October 20, 2020 from: https://commons.wikimedia.org/wiki/File:RIAN_archive_510848_Interplanetary_station_Luna_1_-_blacked.jpg

[5] Planetary Society. (n.d.). Yutu image of Chang’e 3 lander, lunar day 3 (right eye). Retrieved October 20, 2020, from The Planetary Society website: https://www.planetary.org/space-images/yutu-image-of-change-3-lander-lunar-day-3-right-eye

[6] Cernan G. (May 2010). Senate Commerce Science & Transportation Hearing on future of Human Space Flight, Retrieved October 20, 2020 from: https://www.c-span.org/video/?c4530961/user-clip-12-2010-hearing-future-human-space-flight-apollo-astronauts

[7] National Aeronautics and Space Administration. (2014, June 17). Orange Soil. Retrieved October 20, 2020, from www.hq.nasa.gov website: https://www.hq.nasa.gov/alsj/a17/a17.sta4.html

[8] National Aeronautics and Space Administration. (2015, July 8). Apollo 17 Extravehicular Activity. Retrieved October 20, 2020, from https://www.nasa.gov/multimedia/imagegallery/image_feature_2129.html

[9] China Daily/Xinhua. (2019, February 13). China’s Chang’e 4 probe switches back to dormant mode. Retrieved October 20, 2020, from global.chinadaily.com.cn website: https://global.chinadaily.com.cn/a/201902/13/WS5c63d6a7a3106c65c34e924f.html

[10] Sagan, C. (1994). Pale blue dot : a vision of the human future in space. New York: Random House.


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