The path to the Moon is paved with many challenges. What questions do the next generation of space explorers need to answer?
In the first of this two-part series, I explained why scientists wish to return to the Moon, what scientific questions remain and why it is important to find the answers (Tranfield, 2014). In this follow-up article, I describe some practical but non-trivial challenges to fulfilling a successful mission to the Moon, together with potential leads for solutions. Your students, the next generation of space explorers, can put their minds to work to generate ideas and solutions to these problems.
To the poles? The equator? The near side of the Moon? Its far side? The answer to this depends on which scientific questions are being studied. The Apollo missions all landed on the near side of the Moon, near the equatorw1. Scientists think new destinations should be explored to expand our understanding of the Moon. Destinations of interest include the poles, particularly the South Pole–Aitken Basin, which is the largest, oldest and deepest known crater on the lunar surfacew2, making it an interesting study location for lunar geologists.
Furthermore, NASA’s LCROSS mission in 2009 determined that there is ice at the poles in regions that never receive direct sunlightw3. Any experiments that study lunar ice will need to target the lunar poles. The far side of the Moon would also be an interesting new destination for exploration but it is technically more challenging because there is never a direct line of sight between the far side of the Moon and Earth, which would make mission control and communication more difficult.
Or should both go? Humans can do more science than a robot in the same amount of time. Humans can learn quickly from their environment and apply their knowledge to assess a situation. However, a human mission costs a lot more money and endangers more lives than a robotic mission. Commonly, robotic missions are planned first to perform preliminary scientific studies: they use cameras and scientific instruments to study the area prior to human arrival, and deliver supplies in anticipation of later human missions. After a series of successful robotic missions, human missions are planned to perform more complex tasks, including advanced scientific experiments, habitat construction and exploration.
The unique benefits of human exploration are illustrated by the work of Apollo astronaut Jack Schmidt, the only geologist to have stood on the Moon. Jack Schmidt noticed a uniquely coloured orange rock on the lunar surface and he collected samples. These unplanned samples have proved to be extremely important to our understanding of the history of the Moonw4 and would have been missed completely if it were not for the training and experience of Jack Schmidt.
Lunar samples exist in an environment of minimal air and water and away from contamination sources such as humans, spacecraft and Earth’s atmosphere. Studying samples on the Moon therefore reduces the risk of sample change and contamination during transportation. However, the cost and technological challenge of developing and launching scientific instruments that are small enough and that function in lunar gravity limits what analysis can be performed on the lunar surface.
Therefore, samples that require multiple forms of analysis, or complicated instrumentation, should be tested on Earth. This implies that they must be carefully collected and transported to Earth to minimise changes and contamination. The rock boxes designed for the Apollo missions are a good example of how challenging this task can be. They were designed to keep oxygen and water away from the samples during the journey back to Earth; however, in some cases the abrasive nature of the lunar dust degraded the seals and the samples were exposed to air and humidity. Another consideration will be ice core sampling. Ice cores collected by drilling may be damaged by heat generated during the collection process, and collected ice cores will presumably need to be transported back to Earth in specially designed containers to protect the samples from heat, light, radiation, oxygen and biological contaminates.
The NASA curation facility in Houston, Texas, USA, has established successful procedures for handling soil samples under inert nitrogen gas, which ensures that they are well protected from humidity, biological and gas contamination. Dedicated facilities exist for the investigation of samples, and detailed records document what has been done with each sample. New samples, such as ice cores, will require additional method development to make sure that they are handled in a way that protects their scientific value.
Every mission should be built with the goal of furthering our knowledge and our exploration abilities. However, every mission requires a considerable investment in technology, human time and money. As an example, at its peak, 400 000 people worked on the Apollo programme, which cost US$20 billion in 1970w5 (equivalent to about US$120 billion in 2013 when adjusted for inflation). In contrast, the LCROSS / Lunar Reconnaissance Orbiter (LRO) mission cost US$583 million in 2009 (US$633 million in 2013 dollars)w6. The LCROSS / LRO mission was much cheaper than the Apollo programme, but its scientific value was much smaller and did not involve human exploration. When planning large exploration programmes, a balance must be achieved between robotic and human missions to maximise scientific return at a reasonable cost.
In the political and economic landscape today, very few countries have all the necessary resources and skills to launch their own lunar missions. International co-operation, where countries contribute skills and resources, allows all countries to contribute to a shared mission of long-term space exploration, to the Moon and beyond. It will be a challenge to agree which countries can send astronauts and equipment, and this could be an interesting topic to discuss with your students.
The benefits of returning to the Moon from a scientific and exploratory standpoint are enormous. However, many challenges must be overcome to accomplish those goals. This was achieved during the Apollo era, and there is a growing momentum within the scientific community today to do this again.