Human beings' first commercial spacewalk, extravehicular space suit faces test
2024-08-21
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Image caption: The picture shows a SpaceX extravehicular space suit being tested. (Source: US media)
Image caption: The picture shows a simulated image of the "Polaris Dawn" astronauts going out of the cabin for a spacewalk. (Source: US media)
Our special correspondent Chen Yang
The first commercial spacewalk by humans, promoted by SpaceX, is about to kick off on August 26. Not only the items to be tested in this mission are attracting much attention, but also the special extravehicular space suits worn by American astronauts. As the development of the new generation of extravehicular space suits developed by NASA for the Artemis manned lunar landing program is seriously lagging behind, the extravehicular space suits developed by SpaceX may become a substitute solution.
Arrived at the farthest place from Earth in more than 50 years
CNN reported on the 19th that SpaceX has determined the execution schedule for its first commercial spacewalk mission. It is expected that on August 26, SpaceX's manned "Dragon" spacecraft will carry four astronauts on a space trip code-named "Polaris Dawn". They will complete a series of tests in an orbit about 1,400 kilometers from the earth in five days.
According to the US CNBC website, the "Polaris Dawn" mission was originally announced in 2022 and was mainly initiated by US billionaire Jared Isaacman to "break through SpaceX's technological limits and pave the way for long-term human presence in space". This mission will include the first commercial spacewalk, a research program on human health in space, tests to equip spacecraft with "Starlink" Internet communications, and reaching a high orbit of more than 1,400 kilometers above the earth - the farthest orbit humans have been from the earth since the Apollo era. SpaceX CEO Musk said on the 19th that "this will be an epic feat". He described this mission as an "early pioneer in the interstellar era". If the project goes well, hundreds of people will be sent to Earth orbit, the moon, and even Mars in the future based on related technologies.
It is worth noting that this will also be the farthest mission from the Earth since the end of the Apollo manned lunar landing program. In comparison, the International Space Station's daily orbital altitude is about 400 kilometers. During the flight of Polaris Dawn, the manned Dragon spacecraft will pass through the Van Allen radiation belt, which is full of high-energy particles captured by the Earth's magnetic field, which poses a severe test to the spacecraft's radiation resistance.
Isaacman introduced that according to the flight plan for the first day, the spacecraft will look for the time with the least risk of passing through micrometeorite orbital debris after takeoff, and will conduct extensive checks on the performance of the manned Dragon spacecraft before entering the Van Allen radiation belt. "Before rising to an altitude of 1,400 kilometers, it is really important to confirm that there is no fault in the spacecraft."
The second day will focus on about 40 space science and experiments. In particular, with the help of the cosmic radiation environment in high orbit, the astronauts will collect medical data to better understand how the radiation environment affects the human body. They will also conduct a series of other health studies, including measuring bubbles in the blood to study decompression sickness. At the same time, when astronauts are in a microgravity environment, the cerebrospinal fluid pressure in the body will change. The cerebrospinal fluid is directly connected to important nerves around the brain, spine and eyes. Its pressure changes sometimes lead to disturbing symptoms such as blurred vision, namely "space flight-related neuro-ocular syndrome". For this reason, astronauts use some non-invasive technologies to measure its pressure during this mission.
The most critical part of the third day's mission is the spacewalk, which is expected to last two hours. Isaacman said he understands the risk of spacewalking "means he and his companions will be surrounded by death", but they have been training for a long time.
Next-generation extravehicular space suit put to the test
CNN said that the core of the "Polaris Dawn" mission is the spacewalk. For many years, extravehicular activities have been one of the routine tasks of NASA astronauts when the International Space Station needs external maintenance, but no private enterprise has ever attempted such a spacewalk before. According to the plan, Isaacman and Gillis on the manned "Dragon" spacecraft will be responsible for this spacewalk, while Poteet and Menon will stay in the spacecraft for support. Isaacman revealed that since there are many cameras inside and outside the spacecraft, the entire process of the spacewalk will be broadcast live.
"We don't have an airlock on this mission," Gillis told CNN. An airlock is a special decompression chamber on the International Space Station that astronauts use for spacewalks. According to Gillis, the Polaris Dawn mission will take "a very new and different approach" to the pre-breathing process, which involves "slowly reducing the cabin pressure and increasing the oxygen concentration."
During this mission, the special extravehicular space suit developed by SpaceX will also be put to the test for the first time. Unlike the intravehicular space suits that the company has used many times before, the development of extravehicular space suits is very difficult because astronauts need to withstand the radiation brought by high-energy particles in space, extreme temperature changes, and the impact of micrometeorites while ensuring a certain degree of freedom of movement.
Isaacman said that the extravehicular space suit equipped this time is the result of SpaceX's hundreds of hours of testing of different materials. Compared with the old extravehicular space suit currently used in the International Space Station, the new extravehicular space suit released by SpaceX in May is lighter, more flexible and more modern, "thanks to a series of advances in material manufacturing, joint design, enhanced redundancy and integration of the helmet visor head-up display (HUD)".
The main part of the space suit borrows the new thermal management fabrics and flame-retardant materials used on the Falcon rocket and the Dragon spacecraft. The joints of the fingers, shoulders and elbows move more smoothly and have less restricted range of motion. The polycarbonate helmet uses 3D printing technology, and the mask is equipped with anti-glare and anti-fog coatings. When astronauts walk in space, the built-in head-up display in the helmet will provide real-time pressure, temperature and relative humidity readings.
Unlike the old-style extravehicular space suits used on the International Space Station, the space suits used on the Polaris Dawn mission are not equipped with bulky life support systems, but instead receive oxygen support through long hoses connected to the spacecraft. However, this also means that astronauts participating in this mission will find it difficult to walk around as freely as their counterparts on the International Space Station.
Whether it can be selected by NASA is of great concern
CNBC website said that it took SpaceX only two and a half years to develop this new extravehicular space suit. SpaceX said that the space suit was fully tested in high radiation and extreme cold environments, and was even taken to the White Sands Missile Range in New Mexico to simulate whether it could withstand the impact and avoid holes when it was hit by a micrometeorite flying at a speed of 17,000 miles per hour.
SpaceX emphasized that the extravehicular spacesuit is designed with scalability in mind and will allow for individual customization to fit "different human body shapes," so that hundreds or thousands of spacesuits can be provided in the future for people working on the moon, Mars, and in low-Earth orbit.
CNN mentioned that since the old-style extravehicular space suits currently in use were manufactured in the 1980s, NASA has been developing a new generation of extravehicular space suits since the beginning of the 21st century, but progress has always been slow. Therefore, whether the extravehicular space suits developed by SpaceX will be selected by NASA in the future has also attracted great attention from all walks of life. ▲
