First Lunar Surface Radiation Measurements Reveal Long-Term Mission Risk

A small German instrument sent to the Moon on China's Chang'e 4 robotic spacecraft has taken the very first measurements of space radiation as it exists on the lunar surface. The findings come from the DRL German Aerospace Center, which reports that the human body will struggle to deal with this surface radiation over any long duration without adequate protection. Compared to being on the ground, the cosmic radiation on the Moon's surface is around 200 times greater, according to the measurements.

China's Chang'e 4 lunar lander arrived on the Moon's surface in January 2019, bringing, among other things, the Lunar Lander Neutron and Dosimetry (LND) instrument from Germany. In the months since its arrival, the LND has taken measurements of the space radiation found on the Moon's surface, providing unprecedented data that will be vitally important for future lunar missions — particularly ones that will involve long stays on the celestial body.

Space radiation is, of course, a major risk to the human body, which is not equipped to deal with exposure to such levels of radiation. This poses a big problem for space agencies and private companies that plan to send astronauts to the Moon for extended exploration missions, ones that could put them at greater risk of developing cancer and other diseases associated with radiation exposure.

To provide a frame of reference for the measurements taken, DLR Institute of Aerospace Medicine's Dr. Thomas Berger said:

The radiation exposure we have measured is a good measure of the radiation inside an astronaut suit. The measurements result in an equivalent dose rate – the biologically weighted radiation dose per unit of time – of about 60 microsieverts per hour. For comparison: on a long-haul flight from Frankfurt to New York, the dose rate is about five to ten times lower, on the ground a good 200 times. A long stay on the moon is therefore a high burden on the human body.

Key to future lunar missions is the fact that the Moon doesn't have an atmosphere or a magnetic field, which means it is subjected to high amounts of space radiation. With this data, space agencies will be able to leverage computer models to determine the likely radiation exposure for any given mission concept, helping experts develop suitable protective equipment to safeguard astronaut health.