After an eventful trip filled with spacewalks, live music, and much more, the Polaris Dawn crew has returned to Earth. This happened very early this morning after a scheduled deorbit burn and eventual Earth reentry.
The crew splashed down before teams at SpaceX made contact, opened the hatch, and officially completed this 6-day mission. Leading up to the reentry process there was quite a bit of prep to ensure everything went smoothly.
Dragon Splashes Down
Yesterday SpaceX confirmed that the Polaris Dawn astronauts were set to return to Earth and splash down off the coast of Florida on Sunday, September 15 at 3:36 a.m. ET. The night before on the 14th, the crew completed some of the final operations in preparation for reentry.
Specifically, on the Flight Day 5 Update, SpaceX was quoted saying, “Before settling in for their last sleep period of the mission, the crew took some time to connect with their families and began preparing Dragon’s cabin for reentry and splashdown.”
Looking at an image of the splashdown trajectory and specific landing site, you can see it just west of Florida within the Gulf of Mexico. In relation, SpaceX said, “SpaceX teams recently selected this new splashdown location after nearly two weeks of launch delays due to unfavorable weather forecasts for each of Dragon’s seven return sites off the coast of Florida.”
They went on to say, “This location adds greater geographic diversity for Dragon’s return and helps increase the odds of having acceptable return weather forecasts for missions such as Polaris Dawn” they said.
In other words, leading up to the launch of Polaris Dawn there were quite a few delays not necessarily because of the weather when launching the rocket but instead the future forecasted weather when the capsule would return. This has to do with the fact that the Dragon capsule needs to return when the mission timeline is up and can’t just stay like a capsule docked with the ISS could. Fortunately, the more landing options there are, the better chances that one of them has good weather for a return.
Focusing back on the return, about an hour before splashdown SpaceX tweeted saying, “Dragon’s trunk has been jettisoned and the deorbit burn will begin soon.” Normally, Dragon’s trunk not only carries unpressurized cargo but also supports the spacecraft during ascent. One half of the trunk is covered in solar panels that provide power to Dragon during flight and while on-station. The trunk remains attached to Dragon until shortly before reentry into Earth’s atmosphere.
Around that time they shared a video of Dragon as it was passing over Australia. At this point, the nosecone was still open and preparing to be closed.
At 3:00 a.m. ET, Dragon’s deorbit burn was completed and its nosecone was closed. They included a video of that process where you could see both the trunk closing and the entire capsule turning. The Dragon spacecraft is equipped with 16 Draco thrusters used to orient the spacecraft during the mission, including apogee/perigee maneuvers, orbit adjustment and attitude control. Each Draco thruster is capable of generating 90 pounds of force in the vacuum of space.
At this point, the livestream hosts were quoted saying, “While this has been going on the vehicle has initiated the nitrox suit purge. This helps keep our crew members cool and comfortable during reentry.”
Not long after the reentry process had begun and we got some incredible views of the capsule as it made its way back toward Earth. The drogue parachutes which deploy first use the GPS and deploy when the capsule is around 40km in altitude. Eventually, that process occurred, slowing the dragon and crew significantly. Soon after the four main parachutes deployed and slowly opened up bringing the capsule to a safe speed for splashdown.
Only a few minutes later recovery crews were surrounding the capsule and shining lights on it as it was pitch black. They then connected the spacecraft and lifted it onto the recovery vessel before opening the hatch. At that point SpaceX tweeted saying, “Dragon and the Polaris Dawn crew splash down off the coast of Florida, completing the Polaris Program’s first human spaceflight mission.
In an official statement, SpaceX said, “The Polaris Dawn crew combined their expertise, knowledge, and passion for spaceflight to further human space exploration. This was the first human spaceflight for Mission Pilot Kid Poteet, Mission Specialist Sarah Gillis, and Mission Specialist and Medical Officer Anna Menon. Mission Commander Jared Issacman previously flew to space as commander of Inspiration4. This was also the first time two SpaceX employees will be part of a human spaceflight crew, providing valuable insight to future missions on the road to making life multiplanetary” they said.
An Eventful Mission
While only 6 days long, the amount of science and different milestones completed was quite impressive. On flight day 4 for example, SpaceX was quoted saying, “After an exciting and historic spacewalk on Thursday, September 12, the crew spent the majority of their Flight Day 4 focused on science and research. Polaris Dawn partnered with 31 institutions from across the world to create a robust and diverse science research portfolio throughout their time in space.”
“A few of the studies the crew has focused on since arriving on-orbit have included assessing the effects of microgravity on the human airway and veinous system in addition to examining how blood flow restriction alters blood flow in space using ultrasound and smart watches.”
“As humans become a spacefaring civilization, having the proper support system in the event of medical emergencies is key. The Polaris Dawn crew tested out Tempus Pro, a commercial off-the-shelf device that can collect and integrate measurements of health – including blood pressure, heart rate, respiration rate, temperature, and more – along with ultrasound imaging capabilities. The crew was able to use it to assess and compare vital sign data collected pre-flight to that collected during their time on-orbit.”
On the fourth day, “the crew also continued to test and demonstrate Starlink aboard Dragon. One of the biggest tests of connectivity includes the ability to quickly share files. Earlier in the week, the crew recorded Mission Specialist Sarah Gillis playing “Rey’s Theme” by John Williams on the violin. Once complete, the crew successfully sent the files down to Earth over Starlink to help create this special music event named “Harmony of Resilience” they said.
This led to the final full day or flight day 5. Here they mentioned that “Throughout the day, the crew continued to test Starlink, including a 40+ minute, uninterrupted video call with SpaceX teams back on Earth, which took place as Dragon orbited across the U.S. Eastern Seaboard, the Atlantic Ocean, and the Cape of Good Hope.” They also mentioned that the “Starlink satellite for the event maintained its laser link during 16 Draco thruster firings.”
Even before all this, not long after launch, the mission took advantage of Falcon 9 and Dragon’s maximum performance, flying higher than any Dragon mission to date and endeavoring to reach the highest Earth orbit ever flown. They confirmed after that the capsule reached 1,408.1 km, the highest Earth orbit ever flown since the Apollo program. Orbiting through portions of the Van Allen radiation belt, Polaris Dawn conducted research with the aim of better understanding the effects of spaceflight and space radiation on human health.
Then we saw arguably the most notable mission milestone with the spacewalk. At approximately 700 kilometers above the Earth, the crew attempted the first-ever commercial extravehicular activity (EVA) with SpaceX-designed extravehicular activity (EVA) spacesuits, upgraded from the current intravehicular (IVA) suit. SpaceX was quoted saying, “Building a base on the Moon and a city on Mars will require thousands of spacesuits; the development of this suit and the execution of the EVA will be important steps toward a scalable design for spacesuits on future long-duration missions.
During the actual spacewalk, SpaceX clarified that there were three main suit mobility tests meant to test overall hand-body control, vertical movement with Skywalker, and foot restraint.
In total, they conducted just about 36 research studies and experiments from 31 partner institutions designed to advance both human health on Earth and during long-duration spaceflight, and tested Starlink laser-based communications in space.
In terms of what to expect in the future, there are very likely more Polaris Dawn missions coming. In reality, this was the first of three missions Issacman paid for. He mentioned that the final mission would be the first crewed launch of Starship. As for the next mission, it’s not fully clear at this point.
Before this first mission, Issacman was quoted saying, “We’re going to learn an awful lot from Polaris Dawn. It has big, very ambitious objectives. We’ll come back with a lot of data, and that’s what will ultimately inform the second mission.”
Considering how well this initial mission went, they definitely will try something new in the future and continue to launch ambitious Polaris Dawn missions. As for a future Polaris Dawn Starship launch, there still is quite a bit of work left as the company works to get approved for a fifth flight. Something we will have to keep an eye on going forward.
Conclusion
After a very busy 6 day mission that featured the first private spacewalk and a high altitude, the Polaris Dawn crew splashed down early this morning. The reentry process went smoothly and now SpaceX will work to gather all the data from the mission and work toward a second Polaris Dawn launch in the future.