Thursday 21 / November / 2024
Florida: In the early hours of August 27, 2024, the Polaris Dawn mission was delayed due to an apparent helium leak in ground equipment at the launch site, Complex 39A at NASA’s Kennedy Space Centre in Florida. A new launch date was set for Wednesday, August 28, at the original time of 3:38 a.m. US Eastern Time [9:38 a.m. Central European Summer Time /CEST].
If it succeeds, Polaris Dawn will be the first non-government mission to perform a spacewalk. But not only that — it'll do that about 700 kilometres (435 miles) above Earth. The highest ever.
To compare: the International Space Station (ISS) orbits Earth at about 400 kilometres, where the radiation is less intense.
It will also orbit Earth through regions of a highly-charged belt of radiation. There are two of these "Van Allen Belts", an inner and an outer one.
Astronauts tend to avoid the hazardous Van Allen Belts, but they will have to travel through them if humans want to fly to Mars and survive. This privately-funded mission could be a first step toward that goal.
The four astronauts on the Polaris Dawn mission will test new spacesuits, designed by Elon Musk's company, SpaceX, to see how well they protect them against the Van Allen Belt radiation.
SpaceX is also providing the spacecraft — a Falcon 9 rocket and Dragon capsule for the crew — to reach an altitude beyond the current record of 1,373 kilometers, set by NASA's Gemini 11 mission in 1966.
The Polaris Dawn crew consists of Jared Isaacman, Mission Commander, Scott Poteet, Mission Pilot, Sarah Gillis, Mission Specialist, Anna Menon, Mission Specialist and Medical Officer.
Polaris Dawn, the first of a three-part programme, is Isaacman's idea.
Isaacman is a billionaire entrepreneur, who made his money in digital payments and military defense. He previously financed and flew on SpaceX's Inspiration4 mission, the first civilian mission to orbit Earth.
Why are the Van Allen Belts dangerous for humans?
The Van Allen Belts consist of charged particles locked in place by Earth's magnetosphere, which includes its magnetic field.
Earth's magnetosphere traps high-energy radiation particles and protects our planet from solar storms and other threats to daily life from space.
While the outer belt holds high-energy particles from the sun, the inner belt is formed by cosmic rays that interact with Earth's atmosphere.
They were discovered by American physicist James Van Allen in 1958.
The Van Allen Belts range from about 680 kilometres above Earth's surface to what some estimates suggest is about 40,000 kilometers from the surface of the planet. And there's a gap between the first and second belt.
The inner "proton" zone is centered at about 3,000 kilometers from Earth's surface and the outer "electron" zone is centered about 15-20,000 kilometres from Earth's surface.
The Polaris Dawn spacewalk will expose the crew to higher levels of radiation than on the ISS. They hope to collect data on the effects of that radiation as a key scientific experiment.
In 2025, NASA plans to send astronauts beyond the Van Allen Belts to land on the south pole of the moon, and eventually on to Mars. Any data provided by Polaris Dawn will feed into those future missions.
Planned health research on Polaris Dawn
Polaris intends to use data from the mission to create research Biobanks to study the effects of space travel on human biology.
It will investigate the effects of space travel on eyesight and brain structure — a major health risk in space, known as Spaceflight Associated Neuro-ocular Syndrome (SANS).
The team also hopes to contribute to studies into decompression sickness (DCS), another health risk during spaceflight. DCS occurs when nitrogen gas bubbles (or gas emboli) damage human tissue.
