The historic mission Polaris Dawn It’s finally a reality! After several days of delay due to the bad weather conditions forecast for the return, the launch took place at 11:23 Italian time on September 10 from the historic ramp 39A of the Kennedy Space Centerfrom which the Apollo missions also departed. The mission will last all 6 days and will involve mission commander Jared Isaacmanil, pilot Kidd Poteet and mission specialists Sarah Gillis and Anna Menon. The main course, which also determines its uniqueness, will take place on the third day of the mission when, at an altitude of about 700 kmtwo of the four crew members will make the first Private Extravehicular Activity (EVA) in History. EVA, commonly referred to as “space walk”will happen thanks to some specially designed suits by Space X for the mission. Elon Musk’s company is in fact the main partner of Polaris Dawn, so much so that both the launch vehicle, the Falcon 9 rocket, and the capsule containing the crew, the Dragon capsule, were supplied by Space X itself.
The mission is rich in records. In addition to carrying out the first private EVA in history and more than 36 experimentsmany of which are related to the effect of radiation on biological tissue within the Earth’s Van Allen belts, the crew will reach an altitude three times that of the International Space Station (ISS), approximately 1400 kilometers. This is about the highest altitude never achieved by any human mission in Earth orbit in history!
How Did the Polaris Dawn Launch Go?
Polaris Dawn was initially scheduled for launch on August 26thbut, due to helium leaks before, and adverse weather conditions expected at the time of re-entry after, the launch could finally take place only on September 10th. The rocket Falcon 9 of Space X left Pad 39A at the Kennedy Space Center in Florida at 11:23 Italian timeThe launch took place when it was still dark in Florida, as a result the Falcon 9’s nine Merlin engines illuminated almost as if by day the entire surrounding area making the launch extremely spectacular, as you can see from the live Youtube broadcast below (at minute 5:45:15).
About two minutes and 40 seconds After launch, the Falcon 9’s main engines shut down, and that was the booster separation from the second stagewhich continued its race towards space. As is now Space X tradition, the booster was not lost in the ocean, but performed a series of ignitions to return gently and independently on the Space X drone ship in the Atlantic Ocean and thus be able to be reused for a future mission. The Polaris Dawn Dragon spacecraft instead separated from the Falcon 9 second stage about 12 minutes after the launch.
What will happen in the next few days
The capsule will settle on aelliptical orbit initial which will take the 4 crew members to a maximum altitude (apogee) of approximately 1,200 kilometers and a minimum altitude (perigee) of approximately 190 km. After a few orbits, Dragon will fire its engines to change its orbit and raise the apogee to about 1,400 kmhigher than any human has flown since the last Apollo mission in 1972.
After the second day of the mission, the Dragon capsule will fire its engines again, this time for lower the apogee at about 700 kmwhere it will remain until the end of the mission, before returning to Earth. It is precisely at this altitude that it will take place, in third daythe most critical part of the mission: the first commercial “spacewalk” in history. The main objective is to testing the new space suit for extravehicular activities designed by SpaceX.
On the fourth day of the mission the crew will carry out a demonstration of the features of the satellite constellation Starlink. An exciting surprise message is expected that the crew intends to transmit to Earth via SpaceX’s mega-constellation of Internet satellites. The fifth day will instead be dedicated to preparing for the return trip home. Return which is scheduled for the sixth day when the capsule is due to return to Earth and splash down off the coast of Florida.
What are the risks of EVA?
There EVA suit It is only visually similar to the black and white one used for activities inside the Dragon, but in reality it hides some completely different technologiessince it must shield the astronauts from the hostile environment of outer space. The suit must in fact shield the astronauts from harmful radiation of cosmic rays and from incredible temperature variations that occur in the transition from direct sunlight to darkness. At the altitude of the ISS, for example, the external environment has a temperature range of -160 to 120 degrees Celsius.
To further complicate the task, the capsule is also Dragon does not have an airlockas a result of the opening of the hatch to perform the EVA, the entire capsule will be exposed to the vacuum of space. This implies that it will not only be astronauts Jared Isaacman and Sarah Gillis having to use special suits to venture into space, but theentire crew of the Dragon capsule (including Air Force Lt. Col. Scott Poteet and Mission Specialist Anna Menon).
Isaacman and Gillis will take turns exiting the Dragon capsule to test the functionality and maneuverability of their suits. In total, the Polaris Dawn EVA will last about two hours from the start of Dragon depressurization until the hatch is closed and the cabin is repressurized.
