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The countdown is finally upon us for SpaceX’s latest mission: a bold and risky journey into Earth’s Van Allen radiation belts with the goal of completing the first commercial spacewalk.
The mission, called Polaris Dawn, was scheduled to launch at 3:38 a.m. ET on Tuesday, but SpaceX opted for a later launch window of 5:23 a.m. ET because of bad weather at the launch pad. The latest launch opportunity on Tuesday is 7:09 a.m. ET.
SpaceX will broadcast the event live on X, the social media platform formerly known as Twitter that SpaceX CEO Elon Musk purchased in 2022.
This launch attempt comes after several problems hampered the Polaris Dawn crew’s efforts to lift off the ground in late August. First, a problem with ground equipment at the launch site pushed the scheduled date back 24 hours, then weather forecasts forced SpaceX to cancel two more attempts.
Around the same time, a Falcon 9 – the rocket that will power Polaris Dawn’s journey into space – malfunctioned during a routine satellite mission, prompting U.S. regulators to briefly halt the flight of all Falcon 9 rockets. SpaceX received permission to return the Falcon 9 to service on August 30.
Now the company is once again attempting to launch one of its riskiest missions yet. However, weather could still thwart the upcoming launch attempt.
According to a SpaceX post on X, the probability of adverse conditions for a launch on Tuesday is 60% according to the latest forecast.
Further complicating the launch prospects is that SpaceX not only needs clear weather for the mission to launch, but also needs to ensure the seas and winds are calm when the crew returns after their five-day trip from space. The timing of their return could be critical. Because a spacewalk would put a heavy strain on oxygen supplies, the Polaris Dawn mission will only have enough life support to last five or six days in space.
If the weather and forecasts are right and the countdown timer hits zero, SpaceX’s Falcon 9 rocket will roar to life, sending a blinding blaze and a deafening explosion across the launch site at NASA’s Kennedy Space Center in Florida.
The crew will fly strapped into an igloo-shaped SpaceX Crew Dragon capsule atop the rocket, which is about four meters in diameter at its base, as the rocket breaks free from the grip of Earth’s gravity.
After 2½ minutes of burn, the bottom part of the Falcon 9 rocket – called the first stage – has used up most of its fuel. At this point, the first stage will separate from the rocket’s second stage while the top part fires its engine and continues to propel the Crew Dragon spacecraft to higher speeds.
In the meantime, the Falcon 9’s first stage will be guided back to Earth to land on a sea platform where it can be refurbished and reused on future missions. This is a typical SpaceX move that the company says will help reduce the cost of rocket launches.
To reach Earth’s orbit, the Falcon 9 rocket must reach an “orbital velocity” of over 27,358 kilometers per hour. Once the desired speed is reached, the Crew Dragon will detach and must navigate through the vacuum of space using only its onboard engines for the remainder of the mission.
Polaris Dawn is the brainchild of SpaceX and Jared Isaacman, the billionaire founder of financial technology company Shift4 Payments, who made his first foray into space in September 2021 with the Inspiration4 mission.
However, this flight is not a pleasure flight.
Isaacman and his crew members – including his close friend and former U.S. Air Force pilot Scott “Kidd” Poteet and SpaceX engineers Anna Menon and Sarah Gillis – hope to achieve several superlatives on this mission.
First, the SpaceX capsule is designed to take the crew to record altitudes for an Earth orbit, surpassing the milestone set by NASA’s 1966 Gemini 11 mission, which reached 855 miles (1,373 kilometers). If successful, Polaris Dawn would beat that record by about 20 miles (32 kilometers).
The Polaris Dawn space flight would also be the highest human flight since NASA’s Apollo program, which ended in 1972 and took a total of 24 astronauts a quarter of a million miles to the moon instead of stopping in Earth’s orbit.
Polaris Dawn may also mark the greatest distance a woman has ever traveled into space.
At the start of the third day of this mission, the civilian crew will attempt a historic spacewalk at a lower altitude of about 700 kilometers above Earth.
The endeavor will be dangerous because all four crew members and the interior of the Crew Dragon will be exposed to the vacuum of space. Such a situation could make it difficult to reseal the vehicle’s hatch due to the pressure differences. And exposure to the vacuum could cause toxins to be released from the hardware when the cabin is repressurized, although SpaceX says it has taken measures to prevent this from happening.
