The July meeting of Keighley Astronomical society took place on Thursday 23rd. The guest speaker was Dr Martin Braddock from the Sherwood Observatory group in Nottinghamshire. Dr Braddock had previously visited us but his long awaited returned was delayed due to the covid pandemic. In his introduction to the society members present he outlined his role with the British-Swedish multinational pharmaceutical and biotechnology company ‘Astra Zeneca’.
His presentation was titled ‘Challenges and Opportunities for Agriculture and Human Health with Lunar soil’
What is lunar regolith Mr Braddock asked, and then explained that it is a blanket of unconsolidated, loose, heterogeneous superficial deposits covering solid rock. It includes dust, broken rocks, and other related materials and is present on Earth, the Moon, Mars, some asteroids, and other terrestrial planets and moons.
Regolith covers almost the entire lunar surface, bedrock protruding only on very steep-sided crater walls and the occasional lava channel. This regolith has formed over the last 4.6 billion years from the impact of large and small meteoroids, from the steady bombardment of micrometeoroids and from solar and galactic charged particles breaking down surface rocks. Regolith production by rock erosion can lead to fillet buildup around lunar rocks.
The impact of micrometeoroids, sometimes travelling faster than 96,000 km/h (60,000 mph), generates enough heat to melt or partially vaporize dust particles. This melting and refreezing welds particles together into glassy, jagged-edged agglutinates, reminiscent of tektites found on Earth.
The regolith is generally from 4 to 5 m thick in mare areas and from 10 to 15 m in the older highland regions. Below this true regolith is a region of blocky and fractured bedrock created by larger impacts, which is often referred to as the “megaregolith”.
The density of regolith at the Apollo 15 landing site averages approximately 1.35 g/cm3 for the top 30 cm, and it is approximately 1.85g/cm3 at a depth of 60 cm.
The term lunar soil is often used interchangeably with “lunar regolith” but typically refers to the finer fraction of regolith, that which is composed of grains one centimetre in diameter or less. Some have argued that the term “soil” is not correct in reference to the Moon because soil is defined as having organic content, whereas the Moon has none. However, standard usage among lunar scientists is to ignore that distinction. “Lunar dust” generally connotes even finer materials than lunar soil, the fraction which is less than 30 micrometers in diameter.The average chemical composition of regolith might be estimated from the relative concentration of elements in lunar soil.
The physical and optical properties of lunar regolith are altered through a process known as space weathering, which darkens the regolith over time, causing crater rays to fade and disappear.
During the early phases of the Apollo Moon landing program, Thomas Gold of Cornell Universityraised concern that the thick dust layer at the top of the regolith would not support the weight of the lunar module and that the module might sink beneath the surface. However, Joseph Veverka (also of Cornell) pointed out that Gold had miscalculated the depth of the overlying dust, which was only a couple of centimeters thick. Indeed, the regolith was found to be quite firm by the robotic surveyor spacecraft that preceded Apollo, and during the Apollo landings the astronauts often found it necessary to use a hammer to drive a core sampling tool into it.
We study lunar soil “extraterrestrial photosynthesis” so that humans if they return to the Moon can drew on two simple ingredients. Lunar soil and sunlight, to produce fuel, to grow food and to recycle carbon dioxide back into breathable oxygen on long duration crewed missions to he Moon and Mars.
If we are successful. Projected missions can save cargo weight and vehicle space for crewed missions lasting weeks or even months.
Experiments have yielded some posative results. Bubbles of hydrogen and oxygen gas for example using light and water and turns the liquid into those two gasses. On the Moon the water used would come from Lunar Ice and human breath that would have previously gone through a dehydrating process. The astronauts would use the water for drinking.
Can we grow plants in lunar soil ?
The answer to the first question is a resounding yes. Plants can grow in lunar regolith. They were not as robust as plants grown in Earth soil, or even as those in the control group grown in a lunar simulant made from volcanic ash, but they did indeed grow. By studying how the plants responded in the lunar samples, scientits hope to go on to answer the second question as well, paving the way for future astronauts to someday grow more nutrient-rich plants on the Moon and thrive in deep space.
Arabidopsis thaliana, native to Eurasia and Africa, is a relative of mustard greens and other cruciferous vegetables like broccoli, cauliflower, and Brussels sprouts. It also plays a key role for scientists: due to its small size and ease of growth, it is one of the most studied plants in the world, used as a model organism for research into all areas of plant biology. As such, scientists already know what its genes look like, how it behaves in different circumstances, even how it grows in space.
To grow the Arabidopsis, the scientists used samples collected on the Apollo 11, 12, and 17 missions, with only a gram of regolith allotted for each plant. The team added water and then seeds to the samples. They then put the trays into terrarium boxes in a clean room. A nutrient solution was added daily.
“After two days, they started to sprout!” said Anna-Lisa Paul, who is also a professor in Horticultural Sciences at the University of Florida, and who is first author on the paper. “Everything sprouted. I can’t tell you how astonished we were! Every plant – whether in a lunar sample or in a control – looked the same up until about day six.”
After day six, however, it was clear that the plants were not as robust as the control group plants growing in volcanic ash, and the plants were growing differently depending on which type of sample they were in. The plants grew more slowly and had stunted roots; additionally, some had stunted leaves and sported reddish pigmentation.
After 20 days, just before the plants started to flower, the team harvested the plants, ground them up, and studied the RNA. In a biological system, genes are decoded in multiple steps. First, the genes, or DNA, are transcribed into RNA. Then the RNA is translated into a protein sequence. These proteins are responsible for carrying out many of the biological processes in a living organism. Sequencing the RNA revealed the patterns of genes that were expressed, which showed that the plants were indeed under stress and had reacted the way researchers have seen Arabidopsis respond to growth in other harsh environments, such as when soil has too much salt or heavy metals.
This research opens the door not only to someday growing plants in habitats on the Moon, but to a wide range of additional questions. Can understanding which genes plants need to adjust to growing in regolith help us understand how to reduce the stressful nature of lunar soil? Are materials from different areas of the Moon more conducive to growing plants than others? Could studying lunar regolith help us understand more about the Mars regolith and potentially growing plants in that material as well? All of these are questions that the team hopes to study next, in support of the future astronauts traveling to the Moon.
“Not only is it pleasing for us to have plants around us, especially as we venture to new destinations in space, but they could provide supplemental nutrition to our diets and enable future human exploration,” said Sharmila Bhattacharya, program scientist with NASA’s Biological and Physical Sciences (BPS) Division. “Plants are what enable us to be explorers.”
This research is part of the Apollo Next Generation Sample Analysis Program, or ANGSA, an effort to study the samples returned from the Apollo Program in advance of the upcoming Artemis missions to the Moon’s South Pole. BPS helped support this work, which also supports other fundamental plant research, including Veggie, PONDS, and Advanced Plant Habitat.
What might lunar soil it do to human beings ?
Future moon missions are at risk because of lunar soil. It seems harmless, but moon dust can actually damage scientific equipment and be harmful to human health: It is like a sticky powder made from shards of glass.
Neil Armstrong first stepped onto the moon 50 years ago, and his footprints in lunar soil will be there for million of years, according to NASA. There is no wind to blow the footprints away. When they returned to Earth, astronauts from the Apollo missions said that moon dust was sticky, abrasive and stinky.
The next astronauts who walk on the moon will have to contend with plenty of obstacles: the perils of space travel, exposure to high levels of radiation, and a lack of air, gravity, food and water. But dust is surprisingly high on the list of problems that need to be addressed for a successful visit to the moon.
Lunar soil causes a range of problems for astronauts and equipment. It can damage machines and scientific instruments. The first instrument placed on the moon, a seismometer on the Apollo 11 mission, quickly failed because dust caused it to overheat. More recently, China’s Yutu rover died in 2014, and moon dust was the likely culprit of the vehicle’s failure.
Apollo astronauts tried to get rid of the pesky moon dust to keep the lunar module clean. After moon walks, they stomped their boots, brushed the dust off with bristle brushes and attempted to remove it with a vacuum cleaner. They wrapped garbage bags around their legs to try to contain the dust. On the Apollo 12 mission, astronaut Pete Conrad even stripped naked and stuffed his space suit into a pouch to keep the dust contained.
On the moon, dust is much more than a housekeeping chore. It is a dangerous feature of the landscape. In our brief visits during the Apollo era, it scratched astronauts’ visors and weakened the seals on their pressure suits.
Astronauts who have been to the moon say it smelled like gunpowder or some kind of combustion. In addition to damaging their spacesuits, the dust made their eyes water and throats sore, according to The New York Times. Lunar soil could be toxic to humans. Apollo 17’s Harrison Schmitt — the last person to set foot on the moon — described experiencing symptoms similar to hay fever after his moon walk. While it was only a mild allergic reaction, he was only there for 22 hours. Now NASA is preparing for much longer visits, which would expose astronauts and their gear to the abrasive dust for much longer.
A 2018 study suggests that prolonged exposure to lunar dust could put astronauts at risk for developing serious illnesses. The experiment published in GeoHealth by Stony Brook University exposed human lung cells and mouse brain cells to simulated lunar soil. They found that when inhaled, the dust damaged the cells at a DNA level. The researchers warn that prolonged exposure to lunar dust could impair airway and lung function, and lead to bronchitis, inflammation in the lungs and increased cancer risk.
The success of future moon missions will depend, in part, on finding solutions for dealing with the moon’s soil. According to Discover Magazine, researchers have proposed a special vacuum that uses magnets to catch the dust particles.
There aren’t many solutions yet, but Popular Science reports that nine different institutions are now studying moon rock samples to learn about the moon’s geology and chemistry. The samples have been sealed and stored for 50 years, and they are now being released for analysis with the latest technologies. Observations made on those samples will help guide future plans for visiting the moon.
Are we going back to the Moon ?
The first Nasa mission since 1972 to put humans on the Moon’s surface has been pushed back by one year to 2025.
Few observers expected Nasa to make the previous 2024 date, because of a funding shortfall and a lawsuit over the landing vehicle.
But the space agency’s chief Bill Nelson confirmed the delay in a press conference on Tuesday.
Under its Artemis programme, Nasa will send the first woman and the 13th man to the lunar surface.
A US federal judge recently upheld a decision by the agency to award the contract to build a lunar landing vehicle for this mission to Elon Musk’s company SpaceX.
Amazon founder Jeff Bezos had contested the decision, in part because he said the contract was supposed to have been awarded to more than one bidder. However, a funding shortfall from Congress meant this wasn’t possible, according to a rationale published by Nasa at the time of the contract announcement.
Mr Nelson partially blamed the landing mission’s delay on the lawsuit.
“Returning to the Moon as quickly and safely as possible is an agency priority. However, with the recent lawsuit and other factors, the first human landing under Artemis is likely no earlier than 2025,” he said.
However, commentators had been saying since last year that the lander cash problem alone made the 2024 date untenable.
Mr Bezos’ firm Blue Origin had partnered with three other aerospace companies to vie for the prestigious lander contract.
The judgment last week means that a version of SpaceX’s Starship – currently undergoing testing at a site in southern Texas – will be the vehicle used to carry people down to the lunar surface on that mission.
The first mission under the Artemis programme is set to fly in February next year. Nasa will launch the Orion spacecraft on the powerful Space Launch System (SLS) rocket without people aboard.
During this mission, Orion will fly around the Moon on a voyage lasting three weeks in order to test its systems.
The first flight with astronauts – Artemis-2 – will now follow in 2024, Mr Nelson said. It will also fly around the Moon.
Artemis-3 will be the first mission to return to the surface of the Moon since Apollo 17 in 1972. It is set to land at the lunar south pole, which is thought to hold vast stores of water-ice in craters that never see sunlight.
The ice in these craters could be used to make rocket fuel on the Moon, bringing down the cost of lunar exploration because it would not need to be shipped from Earth.
The programme will also see the first person of colour land on the Moon, though it is unclear whether this will happen during Artemis-3 or a later mission.
Monthly meetings at Keighley astronomical society now take a short summer break but resume in September.