Nasa’s Orion spacecraft ‘safe for lunar astronauts exposed to harmful radiation’

Radiation exposure on future Artemis missions to the moon is unlikely to exceed the Nasa limits, experts say.

An artist’s impression of the Orion spacecraft

The shielded areas in Nasa’s lunar spacecraft can protect astronauts travelling to the moon against the harmful effects of space radiation, research suggests.

Chronic exposure to radiation can cause delayed medical problems such as cancer and premature ageing, which may happen over a long period of time.

While the Earth’s atmosphere protects all living beings against cosmic radiation, astronauts venturing deep into space can be exposed to doses equivalent to having 150 to 6,000 chest X-rays.

The Orion spacecraft was designed to help mitigate the effects of cosmic radiation but to find out more, Nasa sent two mannequin astronauts – named Helga and Zohar – on a trip around the moon in 2022 as part of the Artemis I mission.

Artemis I Launch — Nasa’s Space Launch System rocket carrying the Orion spacecraft at the Kennedy Space Centre in Florida (NASA/Keegan Barber/PA)

The dummy crew on Orion were fitted with nearly 6,000 sensors that measured radiation exposure as they ventured into space for 25 days, each occupying a passenger seat.

Early results, published in the journal Nature, suggest the areas in the capsule that are most shielded – such as the central part of the crew module – provide four times more protection than the least-shielded parts.

Within these heavily protected areas, the radiation exposure from large solar particle events remained below 150 millisieverts, which is a safe level for avoiding acute radiation sickness, scientists said.

While travelling through the inner Van Allen belts, the trapped particles that surround the Earth like enormous doughnuts where radiation levels are up to 700 times higher than on our planet, the Orion spacecraft performed a 90-degree turn that reduced exposure by 50%, the experts said.

Radiation dummies Helga and Zohar sat on the passenger seats below on the Orion capsule — Radiation dummies Helga and Zohar sat on the passenger seats on the Orion capsule (Nasa/PA)

Based on their findings, the scientific team at the European Space Agency’s German Aerospace Centre said radiation exposure on future Artemis missions to the moon is unlikely to exceed the Nasa limits for astronauts.

Sergi Vaquer Araujo, lead for the Space Medicine Team at ESA, said: “The Artemis I mission marks a crucial step in advancing our understanding of how space radiation impacts the safety of future crewed missions to the moon.

“With radiation monitors placed throughout the Orion capsule, we are gaining valuable insights into how space radiation interacts with the spacecraft’s shielding, the types of radiation that penetrate to reach the human body, and which areas inside Orion offer the most protection.

“This knowledge is invaluable, as it will allow us to accurately estimate radiation exposure for ESA astronauts before they journey into deep space, ensuring their safety on missions to the moon and beyond.”

Scientists are still going through all the data gathered from Zohar and Helga.

As Zohar flew wearing a specially designed vest that protects against radiation, the team is keen to learn more about the impact it may have had.

The researchers are also looking at data from the mission to understand more about how space radiation could affect the more sensitive areas of the body such as lungs, stomach, uterus and bone marrow.