Update 8:19 p.m. EDT: SpaceX stood down from a launch opportunity Tuesday morning and is pivoting to a 24-hour backup window on Wednesday, Aug. 28.
A commercial astronaut mission of historic firsts is set to launch in the predawn hours of Wednesday morning. The four members of the Polaris Dawn flight will climb aboard a SpaceX Crew Dragon to embark on a roughly five-day, free-flying mission orbiting the Earth.
The crew, led by billionaire-entrepreneur Jared Isaacman, will go further than humans have ventured since the conclusion of the Apollo missions more than 50 years ago. They will also conduct the first commercial spacewalk in history.
SpaceX was originally poised to launch the mission Tuesday morning, but opted to delay the mission launch by 24 hours. The rocket was lowered to a horizontal position around 5 p.m. EDT (2100 UTC) on Monday for “additional pre-launch checkouts.”
After 8 p.m. EDT, the company said, “Teams are taking a closer look at a ground-side helium leak on the Quick Disconnect umbilical. Falcon and Dragon remain health and the crew continues to be ready for their multi-day mission to low-Earth orbit.”
While it’s a bummer to not step into a launch attempt tonight, I’m very proud of the team for identifying an issue and then digging in. Nothing is more important than the safety of our astronauts and the reliability of our vehicles and operation. https://t.co/hBOeYOCUm0
— Kiko Dontchev (@TurkeyBeaver) August 27, 2024
Isaacman is joined in the flight by Pilot Scott “Kidd” Poteet; Mission Specialist and Medical Officer Anna Menon; and Mission Specialist Sarah Gillis. Menon and Gillis will become the first SpaceX employees to travel to space.
Liftoff of the Falcon 9 rocket supporting this mission from Launch Complex 39A is set for 3:38 a.m. EDT (0738 UTC). If needed, SpaceX has two additional launch opportunities within the Wednesday window at 5:23 a.m. EDT (0923 UTC) and 7:09 a.m. EDT (1109 UTC).
Spaceflight Now will have live coverage of the mission beginning about 4 hours prior to liftoff.
Menon, who journals often, said she’s looking forward to chronicling this journey for more than just her own memories.
“I strive to capture a number of things. Especially as we get close to flight, this has been really obvious, time is fast, it’s flying and our days are action-packed leading up to the mission, but especially leading up to launch,” Menon told Spaceflight Now in July. “I try to get down the details because I know I will look back one day and it’ll be pretty blurry, I suspect. I try to get down the details so that one day I can step my mind back into it and remember all the nuances of this experience.
“But then I also try to capture my feelings and the experiences I’m feeling with my crew mates and this fantastic team at SpaceX so that I cannot just transport myself back into the technical details, but also the emotions of going through this.”
Polaris Dawn will be the second time Isaacman journeys to space and the second time the CEO of Shift4 Payments serves as a mission commander aboard a Crew Dragon spacecraft. Isaacman will also become the second person to fly aboard a Dragon twice, following Axiom Space astronaut Michael López-Alegría’s second flight on Axiom Mission 3 (Ax-3) earlier this year.
“It takes a massive team effort to bring a mission like Polaris Dawn to life. Together, we’re making incredible progress for the future—both in space and here on Earth,” Isaacman wrote in a social media post following the conclusion of the mission readiness review Monday morning. “We can do both.”
It takes a massive team effort to bring a mission like Polaris Dawn to life. Together, we’re making incredible progress for the future—both in space and here on Earth.
We can do both. https://t.co/iOuBuTFJHG
— Jared Isaacman (@rookisaacman) August 26, 2024
The Falcon 9 rocket supporting the mission, tail number B1083 in the SpaceX fleet, will launch for a fourth time on this flight. It previously supported the Crew-8 mission to the International Space Station as well as sending two batches of SpaceX Starlink internet satellites into low Earth orbit.
With the Crew Dragon spacecraft stacked on top, the launch vehicle stands at 65 m (213.3 feet) tall. Named ‘Resilience,’ the Dragon will be making its third trip to space after launching both the Crew-1 mission and Inspiration4, Isaacman’s first voyage beyond Earth.
Because Resilience will be launched into a 190 x 1,200 km (118 x 746 mi.) orbit at a 51.6 degree inclination, B1083 will land on the SpaceX droneship, ‘A Shortfall of Gravitas,’ about 9.5 minutes after liftoff.
“The @PolarisProgram mission readiness review just finished and we are currently go for launch in just over 24 hours,” SpaceX founder Elon Musk wrote in a social media post. “Crew safety is absolutely paramount and this mission carries more risk than usual, as it will be the furthest humans have traveled from Earth since Apollo and the first commercial spacewalk!”
“If any concerns arise, the launch will be postponed until those concerns are addressed.”
The @PolarisProgram mission readiness review just finished and we are currently go for launch in just over 24 hours.
Crew safety is absolutely paramount and this mission carries more risk than usual, as it will be the furthest humans have traveled from Earth since Apollo and the… https://t.co/4TEwupwldQ
— Elon Musk (@elonmusk) August 26, 2024
Record distance
During the first day of the flight, the rocket will raise its apogee — the highest point in the orbit — to 1,400 km (870 mi.). At that distance, the Polaris Dawn crew will have flown further from Earth than any humans since the end of the Apollo 17 mission in 1972.
“When you’re going into this environment, you’re dealing with totally different realities than, for example, when you would go to the space station,” Isaacman said in a prelaunch briefing. “It’s a lot of energy going into the vehicle, it’s a lot of energy to take out of the vehicle when you’re coming back home. It’s a different radiation environment. It’s a different micrometeorite orbital debris environment.
“So, we stand to learn quite a bit from that in terms of human health, science and research. If we get to Mars someday, we’d love to be able to come back and be healthy enough to tell people about it.”
The distance will also give Gillis and Menon the distinction of the women who have traveled the furthest from Earth to date. NASA astronaut Christina Koch will break that record when the Artemis 2 mission launches for a journey around the Moon no earlier than September 2025.
Gillis joined SpaceX as it was refining its human spaceflight program leading up to the Demo-2 mission in May 2020, crewed by former NASA astronauts Robert Behnken and Doug Hurley. She said being a part of the mission to prepare Dragon to endure the impacts of the van Allen Radiation Belts and for the first commercial spacewalk has been a great, full-circle moment.
“And so it’s been so cool over the last two years to to almost start that process again, like it’s a different, different development program where we’re adding an entire nitrogen repress system into the spacecraft. We have to make sure there are the right mobility aids to support a crew member performing the EVA,” Gillis said. “It’s been really, really cool and really special for me, given my context on why the Dragon is the way it is, but now getting to actually help develop a brand new spacesuit and test how it integrates into the spacecraft and how it actually can support a spacewalk.
“So that’s been something that’s really, really cool for me to participate in in the last two years.”
Spacewalking on Skywalker
The mission highlight for many people, both within SpaceX and the Polaris Program and beyond, will be the spacewalk happening on the third day of flight.
Because the Crew Dragon doesn’t have an airlock, the entire vehicle will be brought down to vacuum during the spacewalk. Isaacman and Walker will physically exit the Dragon capsule, one at a time, with the support of a hand-and-foot-rail system, called ‘Skywalker.’
The homage to the ‘Star Wars’ franchise follows the naming of the rocket itself, the Falcon 9, which is a hat tip to the Millennium Falcon, seen throughout the films.
Much of the training over the past two-and-a-half years has been working on the prebreathe protocols to purge nitrogen from their systems. The process will start about an hour after they arrive on orbit and continue slowly over a couple of days before flight day three rolls around.
“This prebreathe is really designed to help mitigate the risk of decompression sickness when we actually go to vacuum in the spacesuits,” Gillis said. “Over the course of about 45 hours, we’ll actually slowly drop the cabin pressure and raise the oxygen concentration to help mitigate the risk.”
The entire spacewalk will last around two hours and SpaceX intends to livestream the event using the various cameras placed around the Dragon spacecraft. Speaking as someone who trains astronauts on working with the capsule and the spacesuits, Gillis said she’s eager to field test them herself on orbit.
“I think most interestingly is what is that actually like in space? It’s end to end. You know, we started from design concept through to actually experiencing that on orbit. And so I’m really, really interested to see what we learn from doing the EVA, what ways we need to modify our training for the for future spacewalks,” Gillis said. “But it should be really interesting to see that that full design evolution come come together.”
Poteet said the training that he and his crew mates experienced from the teams at SpaceX gives him great confidence in the mission that lies ahead.
“Spending thousands of hours in the simulator is what helped build our confidence for dealing with any scenario that Melissa decided to throw at us,” Poteet said, referring to one of the SpaceX trainers. “It was very challenging… but experiencing those and trying to identify what is wrong and then how do we work together to solve those issues certainly built our confidence to be able to handle those very low probability (scenarios) on orbit.”
source: spaceflightnow.com