Specialists are now gathering potential photography assignments for NASA’s manned lunar flight Artemis 2, expected to take place in September 2025.
Hidden in them Orion spacecraftthey will be hurled to the moon by NASA Space launch system (SLS) rocket and travels approximately 4,600 miles (7,400 km) beyond the other side of the moon during the almost 10-day trip. To help them prepare for their journey, lunar scientists have started planning photographic, fun ‘Kodak Moments’ for the four-member Artemis 2 crew to take into account when looking outside the window.
Surprisingly, one conceivable task for the astronauts is to monitor flashes of light on the moon’s surface. It turns out that astronauts observed three collision-induced flashes during the Apollo moon landing program meteors. What are the chances that Artemis astronauts would see the same thing?
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Color variations
“We worked with the Artemis 2 crew to identify imaging and observation targets/plans for them during their journey to and from the moon,” said Noah Petro, project scientist for Artemis 3 and is the current project scientist for NASA Lunar Exploration Orbiter mission.
Petro told Space.com that plans are being made to take advantage of the Artemis 2 crew to observe and photograph the moon as regularly as the flight plan allows.
A focus of these preparations is choosing photographic objectives for the period of time during the crew’s closest approach to the moon, Petro says. “At that point, our plan is to have the crew members observe the moon, looking for color variations on its surface, as was observed from orbit by several Apollo crew members.”
Also, the Artemis 2 crew could make observations of surface texture and properties, Petro adds, to validate or refine already existing spacecraft data.
What are the chances?
Observations on Earth indicate that five meteoroids the size of a ping-pong ball hit the moon every hour, said William Cooke, chief of the NASA Meteoroid Environments Office at the Marshall Spaceflight Center in Huntsville, Alabama.
Telescopes located on the NASA In the center, Cooke notes, one hit is observed every two hours in an area of 4 million square kilometers. “Current spacesuits can be pierced by particles 71 times smaller than this,” he says, “so there are more than 10 million dangerous meteoroids hitting the moon every hour.”
But that’s the entire surface of the moon, Cooke quickly adds, and that’s 38 trillion square meters. “Astronauts have a surface area of only one square meter, so the chance of an impact on a moonwalker’s suit is quite small.”
As for the frequency of the collisions, “We normally observe an impact every two hours of observation time,” Cooke says. However, during the Geminids meteor showerrates will increase by a factor of more than 10, from 0.5 per hour to more than 5 per hour, he says.
Pinprick of light
“There are a lot of meteoroids in the Geminid Stream! Apollo 17 was in orbit around the moon during the 1972 Geminids – a perfect time to see impact flashes,” says Cooke. Crew members at other times had to look ten times longer to see a flash, he says.
“Hey, I just saw a flash on the moon’s surface,” Schmitt said over the radio during the Apollo 17 voyage. “It was just north of Grimaldi… you could see if you have anything on your seismometers, although a small impact would probably produce a fair amount of visible light,” the astronaut reported.
“It was a bright little flash right by that crater. See the crater right on the edge of Grimaldi,” Schmitt. “Then there’s another one north of there. A fairly sharp one north of it is where there was just a pinprick of light.”
The obvious, Cooke concludes, is that impact flashes typically last much less than a second, “so you would need a video camera to record them. The chance of catching a flash in a still, short-exposure image is negligible small.”
New large craters
William Bottke is a leading lunar scientist at the Southwest Research Institute in Boulder, Colorado.
If the Artemis 2 lunar astronauts see anything interesting, Bottke advises that they should try to document the location of the site so that follow-up observations can be made.
“Sometimes some flashes are large enough to represent new, large craters on the lunar surface,” Bottke says, and those locations could potentially be observed by NASA’s patrolling Lunar Reconnaissance Orbiter, or by another instrument in the future.
Risk: low but not zero
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The fact that Apollo crews saw these flashes, as did observers on Earth, seems to indicate that this is not rare. So should that be a concern for future permanent crews lurking around on the moon?
The Soil and the moon are both often hit by small impactors and meteoroids, Bottke answers. He points to studies from NASA’s Meteoroid Environment Office on the danger to astronauts from meteoroids and small impacts.
“In general, the risk is considered low but not zero,” Bottke says. “Furthermore, the longer you stay on the moon, the greater the cumulative risk.”
Meteoroid impacts will be a bigger concern for moon bases, Bottke says. “These structures will have to be built with meteoroid impacts in mind. Some type of shielding or strong material will likely be needed when they are built.”
The lunar science community is very interested in what observations Artemis crews might make while on the moon.
“While we don’t expect the crews to photograph flashes,” says NASA’s Petro, “their images and descriptions of the surface and lunar environment will be an important addition to lunar science.”