SpaceX's Polaris Dawn mission, which took billionaire Jared Isaacman and three other crew members into space in a Crew Dragon, made headlines for featuring the first private spacewalk. While the flight was hailed as historic for that reason, Isaacman said the trip was not just for fun, but also to contribute to science.
Research in the Polaris program, which is scheduled to include three flights, focuses particularly on human health and the effects of space travel on the body. The current mission is being studied by the Baylor College of Medicine, with astronauts donating blood and undergoing extensive biomedical testing before and after the flight.
What sets the Polaris Dawn mission apart, however, is its altitude: 870 miles above the Earth's surface, to be exact. That's far higher than the International Space Station's usual altitude (around 250 miles), and means Polaris Dawn is the farthest mission from Earth humans have experienced since the Apollo missions.
The effects of space travel on the body
At this altitude, the spacecraft passed through Earth's inner Van Allen Belt, a region of charged particles that protects the planet from dangerous radiation. Crew members are equipped with sensors that measure their cumulative radiation exposure during the mission, and there is a sensor inside the spacecraft that detects the different types of radiation in the environment.
“It is an opportunity to see what kind of [radiation] “The radiation we're exposed to as they move further and further away from the Earth's surface,” explained Jimmy Wu, deputy director of the Translational Research Institute for Space Health at Baylor. “That's something we don't have a lot of data on because we're limited to the number of people who have been that far away. So understanding that is critical.”
Short and sweet
From a health researcher's perspective, more data is always welcome, whether it comes from a space mission or a private mission. Although the Polaris Dawn mission is much shorter than a typical astronaut deployment on the International Space Station, at five days rather than six months or more, it still offers the opportunity for a different kind of research.
If you want to study the long-term health effects of spaceflight, such as loss of muscle and bone mass, you need a longer duration mission. However, for certain effects of spaceflight, the body adjusts to a baseline state within a few days or hours, and these are ideal research topics for short missions.
Astronauts can experience space sickness when entering or exiting a microgravity environment. It is not yet known why some people suffer more than others, especially in the first few days of a space flight.
“It is an opportunity to see what kind of [radiation] Exposure we face as they move further and further away from the Earth’s surface”
While space sickness seems to be more of a nuisance than a major problem, Wu points out that impairment immediately after a takeoff or landing can be a major problem.
“You're going to the moon. There's no welcoming committee to take care of you after you land,” he said. “What would happen if there was an incident during landing and you had to eject? Would you be able to do that if you've lost your sense of direction and up and down?”
Another important area of health research is the relationship between different factors in spaceflight and how they affect each other. It's not just about understanding the effects of microgravity, radiation exposure, or isolation and confinement – it's about understanding the cumulative stresses that spaceflight imposes on the body.
The vastness of humanity
While proponents of space tourism argue that it improves access to space and even democratizes it, that's hard to accept when the only people going into space are billionaires like Isaacman and their friends.
But it is also true that the astronauts currently flying on space missions are not representative of the general population. This is partly necessary—it is only common sense to select astronauts who are healthy enough to withstand the physical challenges of space travel—but it is also partly a legacy of racism, sexism, and questions about who is considered worthy of becoming an astronaut.
Efforts are underway to make the international astronaut corps more diverse, and the European Space Agency recently selected its first disabled astronaut for training. However, people who take part in space missions still represent only a very small proportion of humanity, and so the only data we have on the health consequences of spaceflight relate to this small group.
“I think it's really important to understand the full range of humanity so that we understand the full range of human achievements in spaceflight, not just the people who were our early pioneers,” Wu said.
Although commercial astronauts have so far been primarily, though not exclusively, white men, they represent a broader range of ages and backgrounds than is typical for professional astronauts. And future commercial missions could help expand the data pool on human health in space. The Polaris Dawn crew, for example, is made up of an equal number of men and women, allowing for comparisons between the sexes.
TRISH is setting up a database that will collect biomedical data from both Polaris Dawn and future commercial space missions. The goal is to collect data from a broader range of people, not just well-trained, young astronauts with no health problems, to see how people with underlying conditions such as diabetes or cardiovascular disease fare on space missions.
“We need to start collecting this data because we don’t know how this [conditions] behave in space,” Wu explained.
An impact on the earth
One experiment on the Polaris Dawn mission that could have a huge impact seems simple enough at first glance: testing a miniaturized ultrasound scanner that the crew can use to scan themselves and collect medical data. Researchers are studying not only the performance of the device, but also how best to train the crew to use it.
“We need to start collecting this data because we don’t know how this [conditions] would behave in space”
While adapting hardware for space presents its own challenges, preparing to use a portable medical scanner, especially for those who are not trained medical professionals, is all about training and procedure.
“There's a line of research on this: How can we provide them with pre-flight training before the mission starts so they understand at least some of the basics?” Wu explained. “And then can we provide them with just-in-time training? So can we give them a refresher while they're preparing for the actual activity?”
Finding the best way to teach laypeople how to use diagnostic equipment and making those devices as small and robust as possible will not only prove useful in space. It could also be invaluable here on Earth, for example in rural areas or regions where people don't have access to doctors.
“We're talking about the concepts of health equity and how we can provide care to underserved, resource-poor environments,” Wu said. “If you can keep someone healthy in the isolation of space, you should be able to do it anywhere on Earth.”