Explainer: Why Polaris Dawn is a daring, multiple record-breaking spaceflight

Today, 12th September, 2024, two American astronauts have done the unthinkable - flushed out all cabin air from the spacecraft that they call home, donned extravehicular activity suits (temperature, pressure controlled space suits that provide oxygen, communications, data monitoring), opened the protective hatch of their spacecraft, and temporarily exited into the vast nothingness of space. While two astronauts took turns and performed a spacewalk, two others sat inside the capsule, wearing the same suits that their spacewalking counterparts wore, monitoring all the activities that were unfolding.

All this action unfolded 700 kmabove the earth's surface. For those who aren't familiar with the domain of human spaceflight, this feat might sound routine. However, this five-day Polaris Dawn mission is among the gutsiest space ventures thus far of the 21st century. Here's why:

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First private spacewalk

Over the last three decades alone, astronauts have performed nearly 470 spacewalks. In fact, the first spacewalk (floating in space, outside the protective confines of the spacecraft) was performed by Soviet Cosmonaut Alexei Leonov, back in March 1965. However, all these efforts have been undertaken by government-trained astronauts. In the Polaris Dawn mission, all four crew members are private citizens and are undertaking this mission in partnership with the private firm SpaceX. The rocket that flew them to space, the spacecraft that houses them, the spacesuits being used, all of them are privately designed and developed by SpaceX. The crew members are: Jared Isaacman, a billionaire who funded this mission, Scott Poteet, a former US Air Force aviator, SpaceX staffers Anna Menon and Sarah Gillis, both of whom are with ground teams that work with astronauts. Other than Isaacman, all are undertaking their maiden spaceflight.

The furthest human spaceflight in 52 years

Between 1969-72, the American Apollo series of missions attempted multiple crewed Lunar missions, which also included the iconic Apollo-11 moon landing. The moon is four lakh kilometres away from the earth and this is the furthest that humans have gone from the home planet. After the Apollo missions, human spaceflight has been restricted to the International Space Station and its precursors, all of which are positioned 400 km above the earth. Polaris Dawn flew to a maximum altitude of 1400 km, which is the highest that humans have ventured, since the Apollo-era. This is also the furthest that a non-Lunar mission has ever flown and the furthest that women have flown.

A risky flight through earth's radiation belts

TheVan Allen radiation belts are zones of energetic charged particles, primarily originating from the solar wind, that are captured and held around Earth by its magnetic field. These belts extend from 640 km to 58,000 km above the earth. The spacecraft carrying the Polaris Dawn crew, flew into this region. For accomplishing this feat, their craft and on-board systems would be shielded adequately to protect from the risks posed by radiation. It is also crucial that the craft protect its occupants from higher-than-usual doses of radiation. As humans prepare to perform missions to Moon and Mars, plan for long-term bases on other celestial bodies, understanding radiation is crucial.

19 people in space, circling the earth

Right now, there are 19 people who are in space, circling the earth. This is the highest number of people at a time who are in space. This showcases how far humanity has come in its ongoing and never-ending journey to explore the unknown. Usually, there are about 12 people or so in space, on a constant basis, considering that there are two orbiting labs - International Space Station and Chinese Tiangong space station.

At present, there are nine crew members aboard the International Space Station, three aboard the Chinese Space Station, three crew on the Soyuz MS-26 capsule that is flying to the space station, and four members aboard the SpaceX Crew Dragon that is performing the private mission Polaris Dawn.

Notably, unlike the other well-trained, government-representing astronauts, the 'Polaris Dawn' crew undertook their space voyage as a personal risk, with a common determination to push humanity further in an endless journey of space exploration. The EVA suits they've been testing are the first version of what SpaceX intends to use in the long-run for their missions that take humans further into space, to other planets. The Polaris Dawn crew are also performing close to 40 experiments and testing out new technologies that can push the limits of human-led space exploration.