In other words, the main threat facing the crew of Artemis 2 does not lie in any kind of danger associated with the trip itself whether the flight into outer space, the travel distance, or launching. The threat lies in radiation exposure that will inevitably occur once the astronauts venture outside Earth’s protective magnetosphere, where any strong solar particle event can quickly lead to health consequences.
Indeed, NASA’s approach to protecting against this threat is based on the principle of layers, where layers consist of both passive radiation protection elements and active measures. On the one hand, Orion itself can be considered a protective layer; thanks to the results of radiation measurements taken during Artemis I, NASA scientists got a more accurate picture of those parts of the cabin that are well-shielded by the walls of the spaceship. In particular, there are quite a few such spots, as during an uncrewed flight thousands of passive dosimeters and dozens of active ones were placed inside the ship. And the results clearly show that certain parts of the cabin receive less radiation exposure, which is critical given each additional millirad of protection in space.
According to Stuart George, who works at NASA, the spaceship is a fairly good shelter from a solar storm due to its density. However, it does not mean that astronauts need not pay attention to space weather at all. In particular, during the mission they will wear personal dosimeters, and besides, the six HERA radiation sensors will monitor dose rate changes aboard the spacecraft. Also, both NASA and National Oceanic and Atmospheric Administration (NOAA) specialists will provide the crew with data on solar activity, monitoring sunspots and measuring radiation coming from the Sun. Meanwhile, if necessary, the crew will be notified by alarms and warnings issued inside the spaceship whenever radiation levels exceed certain thresholds.
However, what is key to protecting astronauts from harmful rays? First of all, these are actions that must be performed as soon as possible – moving the crew into well-shielded areas, and also reconfiguring the ship cabin itself. To do this, all stored objects should be moved from the central storage into the place with the weakest protection this procedure, incidentally, is called massing. Astronauts will also have places in Orion cabins with increased protection close to storage compartments and near the toilet. “It’s more like you’re sitting in a bathtub and it’s gradually filling with water.” says George regarding filling the cabin with solar particles.
Radiation protection of astronauts on Artemis 2 also involves overcoming the Van Allen belts and spending several days under the impact of galactic cosmic rays. In addition, in the case of solar particle event radiation levels can increase sharply during this time. According to NASA experts, without taking into account any possible solar particle events, the radiation level during the flight will be almost equivalent to radiation exposure of one month spent on the International Space Station. Therefore, the experience of 1972 can serve as a reference point in terms of potential risk factors. Patricia Reiff told Live Science that back then astronauts would have received “nearly lethal dose” while traveling on Apollo. Given this experience, Artemis astronauts will need additional radiation precautions.