Deep Space Radiation Is A Serious Concern If We're Ever Going to Mars, New Study Suggests

A new study examining the long-term effects of exposure to deep space radiation has found some alarming results. 

Apollo astronauts, specifically those who traveled to the Moon, are experiencing higher rates of cardiovascular problems due to their exposure to the levels of galactic cosmic radiation (GCR) associated with space beyond low-Earth orbit (LEO), according to a Florida State University researcher.

Of the Apollo program’s 11 manned flights, 9 traveled beyond LEO to the Moon. These flights exposed the only 24 individuals to ever travel that far to levels of GCR that no other astronaut or cosmonaut has experienced since. The last Apollo mission flew in 1972. Decades later, the effects of radiation exposure can be seen in the form of cardiovascular complications.

Photo credit: NASA

Photo credit: NASA

In a new paper in Scientific Reports, FSU Dean of the College of Human Sciences and Professor Michael Delp, lead author on the study, is the first to examine the mortality of these deep space travelers. The research shows that 43 percent of deceased Apollo astronauts died from cardiovascular-related issues. This number is nearly five times higher than astronauts who have not traveled beyond LEO. 

“Of the 24 men who flew into deep space on the Apollo lunar missions, eight have died and seven were included in the study. The eighth - Edgar Mitchell - died after the data analysis had been completed.” PRESS RELEASE 

Yesterday, spoke with Kathryn Hableton, NASA representative for Human Exploration and Operations Mission Directorate (International Space Station, commercial crew and cargo, Space Launch System, Orion, Asteroid Redirect Mission and Future Human Exploration) regarding the recent study: 

“NASA monitors astronauts for post-mission health problems throughout their lifetime. Medical monitoring programs, as well as prospective studies and medical research, help further understand the effects of radiation on astronauts during long duration spaceflight, including our Journey to Mars. The agency recognizes the importance of this research area and supports a comprehensive program.
With the current limited astronaut data referenced in the study, it is not possible to determine whether cosmic ray radiation affected the Apollo astronauts. Limitations of the study include the small number of astronauts in the Apollo program and lifestyle factors that cannot be quantified - such as family genetics and diet - which are known risk factors for cardiovascular disease.
NASA recommends against drawing definitive conclusions when dealing with a small number of people that excludes other significant factors.”

Read NASA's Challenges of Spaceflight: Dealing with Space Radiation

Image courtesy of NASA

This research is of particular interest now as not only NASA, but commercial companies and other space agencies are preparing to send humans back to the Moon, and eventually to Mars. The European Space Agency (ESA), Roscosmos, and China are all currently in the planning stages for new lunar missions, while Elon Musk is slated to reveal SpaceX’s Mars colonization plans this September.

Delp is currently working with NASA and Apollo astronauts to conduct further research into their cardiovascular health, but the long-term effects of deep space exploration on the human body are still largely a mystery. 

Since Apollo, the International Space Station (ISS) has served as the world’s most valuable resource in studying the health effects of spaceflight. In the 15 years since the orbital laboratory has been in operation, thousands of research hours have contributed to our current understanding of how the hostile, weightless environment of space impacts the human body.

Prolonged exposure to microgravity, radiation, carbon dioxide, and the excessive noise associated with life aboard the ISS have lasting effects even while in low Earth orbit. Musculoskeletal and eyesight deterioration, decreased red blood cell production, the slowing of cardiovascular system functions, and a weakened immune response are all expected after a few months in space. For this reason, NASA set limits years ago to help protect astronauts from radiation exposure and the long-term effects of weightlessness on the human body. 

The average mission duration of a crew member aboard the ISS is about six months. During this time, ISS crews undergo a strict exercise regiment, and a routine series of health checks to deter such risks. 

Image courtesy of NASA

A rare exception to the rule, astronaut Scott Kelly and cosmonaut Mikhail Kornienko returned to Earth earlier this year after completing nearly a year in space. As a contributing effort in NASA’s Journey to Mars, Kelly lived aboard the ISS for a duration of time roughly equivalent to that of a mission to the red planet. While Scott spent a year in space, his twin brother Mark remained on Earth to serve as a controlled comparison model. The two continue to undergo regular medical testing to help NASA better understand the effects of long-duration space travel in preparation for future Mars missions.

Kelly recently added his voice to a number of others at the space agency at a hearing held by the House Subcommittee on Space, urging congress to expand NASA’s ability to provide lifetime healthcare to current and former astronauts. Currently, NASA is only permitted to provide medical care to active astronauts. Those who have hung their spacesuits up for retirement are forced to consult personal physicians who are often unqualified to assess space-related health concerns.

Every day, I was exposed to ten times the radiation of a person on Earth, which will increase my risk of a fatal cancer for the rest of my life.
— Scott Kelly

Many health issues still unanswered, NASA’s current Journey to Mars mission timeline lacks the expediency associated with the Apollo era Cold War rush. After completing its first flight test (EFT-1) last December, the Orion Crew Module will serve as NASA’s new exploration-class vehicle that will ferry astronauts back to the Moon and eventually to the red planet.

EFT-1 was an unpiloted mission that tested many of Orion's capabilities. Among these, the launch abort system, the heat shield's ability to protect the capsule during atmospheric reentry, and parachute deployment were all put under a microscope during and after the craft's 4.5 hour long mission. But EFT-1 had one other crucial purpose: testing radiation levels. 

Orion spent the majority of its mission inside the Van Allen Belts, regions of dense radiation surrounding Earth. Future crewed missions won't spend nearly as much time inside the Van Allen Belts, but long-duration deep space missions will expose crews to more radiation than that experienced by the Apollo astronauts, and NASA is depending on Orion to provide protection.

Soon to serve as Orion's launch vehicle, the Space Launch System (SLS), the agency’s Mars rocket currently under development isn’t actually slated for a trip to Martian orbit until the 2030s. Its first flight, Exploration Mission 1 (EM-1) is currently scheduled for no later than November 2018.

Part of these exploration missions include NASA’s Asteroid Redirect Mission. Targeted for the mid 2020s, NASA hopes to redirect an asteroid into a high lunar orbit - known as cislunar space - and then secure that asteroid to a cislunar orbital habitat, which crews will then occupy periodically for up to 60 days at a time; a time-limit set in order to limit radiation exposure.

Orion will dock with this habitat module, which will serve as a testbed for the technologies that will allow humans to not only survive, but to live and work effectively during the long journey of a martian mission.

Orion docked to Lockheed Martin's Cislunar Habitat module concept.  Image courtesy of  Lockheed Martin .

Orion docked to Lockheed Martin's Cislunar Habitat module concept. Image courtesy of Lockheed Martin.

Deep-space radiation in mind, NASA is considering four companies as part of the agency’s NextSTEP program to design and construct the habitat that will harbor the first humans to return to lunar space since 1972. In interviews with the Observer, representatives from Lockheed Martin and Bigelow Aerospace - two of the companies competing for NASA’s NextSTEP contract - responded to questions about their habitat’s radiation shielding capabilities. 

Lockheed Martin’s Space Exploration Architect Josh Hopkins hopes to utilize the “locker” spaces behind Orion’s seats. Squeezed between the capsule’s seats and heat shield, the crew would surround themselves with consumables from the storage compartment. According to Hopkins, “things like water, food, and plastics tend to be fairly good shielding.”

In a separate interview, Bigelow Aerospace President Robert Bigelow speculated lining the interior circumference of their proposed expandable habitat with water tiles, providing a similar barrier of protection from radiation exposure. 

Bigelow Aerospace sent their first crew-rated module to the ISS earlier this year. The first of its kind, the Bigelow Expandable Activity Module (BEAM) is more fabric than metal, and provides an expandable habitat concept significantly lighter than similarly sized space modules. BEAM will stay docked to the space station for two years while ISS crews routinely test the module’s radiation levels, as well as its resilience to thermal, structural, and mechanical stresses. If it passes, the company hopes to modify its B330 module concept for interplanetary use.

B330 Modular Station concept.  Image courtesy of Bigelow Aerospace.

B330 Modular Station concept. Image courtesy of Bigelow Aerospace.

Those at NASA aren’t the only ones with their eyes on the red planet however. SpaceX CEO Elon Musk has been very outspoken regarding the space company’s goals for martian colonization. SpaceX has already released its “Red Dragon” concept, a crewed Mars lander, that it hopes to test fly as early as 2018.

Aiming for 2022, SpaceX then plans to send what Musk has referred to as the Mars Colonial Transporter, which would be used to send humans to Mars as early as 2024. Way ahead of NASA’s timeline. 

Shrouded in mystery, Musk is expected to reveal his full plan for martian colonization at this year’s International Astronautical Congress, in Guadalajara, Mexico. One question that is now sure to be on everyone’s mind: what about the radiation?