Already this Sunday (September 24), after billions of kilometers traveled through the Solar System, the American probe OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer) will return to Earth. As it passes by our planet, it releases a reentry case containing samples of rocks that represent the original material from which our Solar System formed. The OSIRIS-REx probe took these samples on October 20, 2020, on the planet Bennu, which circles the Sun between the orbits of Earth and Mars. The OSIRIS-REx mission is the first US project to collect samples from an asteroid. Scientists believe that the valuable material will open a window to a view of 4.5 billion years into history, when our Sun and planets were just forming.
Exploded view of the OSIRIS-REx reentry case
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Before the eagerly awaited scientific analysis, the reentry case will have to withstand temperatures twice that of lava. The pod will also become the second-fastest human-made object on record to enter Earth’s atmosphere. As the pod enters the atmosphere at 36 times the speed of sound, it begins to decelerate and its heat shield rapidly heats up. After descending into the lower layers of the atmosphere, the pod will have to deal with the weather at the landing site, be it blue skies or strong winds, rain and other adverse effects. But whatever the weather, the pod will land in the Great Salt Lake Desert, an arid region known for scorching summer heat and a salt-covered surface left over from the presence of an ancient lake.
Most of the focus during the landing will be on the technical aspects of the probe and the landing pod, but the team of scientists and meteorologists will also be closely monitoring the weather, which can significantly affect the recovery of the pod. “Even before we started seven years ago, the housing had to be designed for all the weather conditions we thought we could expect in October in Utah.” recalls Eric Queen, an engineer with the EDL (Entry, Descent and Landing) team at the Langley Research Center in Hampton, Virginia. The case was therefore designed to be impenetrable, for example, to lightning or ice.
“When you’re parachuting, your biggest concern is the wind,” says Mark Johnson, who led landing analysis for Lockheed Martin. The reason is simple—wind speed and direction can affect exactly where in the 58-by-14-kilometer area at the Utah Test and Training Range southwest of Salt Lake City the casing lands. “The landing area is considered a safe and controlled location,” says Kenneth Getzandanner, OSIRIS-REx flight dynamics manager, adding: “It was also the landing area for the Stardust mission, so there is a historical experience here.The team responsible for the OSIRIS-REx mission also had to think a lot about the conditions on the surface itself. Late summer is the usual desert monsoon season, so torrential rains can quickly saturate the clay loam. The resulting mud, resembling wet mortar, greatly impedes the movement of all-terrain vehicles that can be deployed to assist the helicopters in the search and transfer of the case.
Construction of the return case
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Translation: Author
„By the end of the monsoon season, we should know how much rainfall has fallen here and the condition of the salt flats,” said Eric Nelson, a U.S. Army meteorologist who works with mission security, adding: “A good indicator is Bonneville Speed Week, the annual August racing event.” Because these races went off without a hitch, so Nelson can say, “Jwe’re probably fine.To ensure a safe landing of the OSIRIS-REx return pod, weather balloons are launched in the area in the days leading up to the landing. These single-use devices rise to a height of about 18 kilometers, which is approximately twice as high as where commercial airplanes travel. Ascending at 5.5 m/s, the balloons measure temperature, humidity, air pressure and wind, transmitting this data continuously before bursting high in the atmosphere. Ground teams will attempt to model a likely landing area from this data.
OSIRIS-REx Probe Return Case
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Let’s describe how exactly the return of the sample case to Earth will take place. It all starts the moment the pod detaches from the OSIRIS-REx probe. At that time, it will have approximately four hours until it touches the atmosphere over the US West Coast. The roughly 45-kilogram reentry pod traveling at hypersonic speed will rely on a protective system that consists of a heat shield made from a lightweight ablative material developed at the Ames Research Center in California’s Silicon Valley that is designed to withstand extreme temperatures.
Ground and airborne radar and infrared tracking systems will monitor the descent of the pod. Several machines will be used in the event, including the WB-57 high-altitude aircraft in the service of the Johnson center in Houston. Their task will be to track the path of the pod through the atmosphere using their on-board visual and infrared systems. As soon as the pod speed drops to about 1,850 km/h, the stabilization parachute will open above the landing area.
Landing sequence
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The main spherical parachute opens closer to the surface and ensures a soft landing. Unlike other designs, the spherical shape is less susceptible to being affected by wind, which increases the stability of the case’s descent. This reduces the risk of the wind blowing the falling casing out of the marked area where it would be much harder to find.
As soon as the case touches the surface, a specialized team goes to it to ensure that it is picked up. The samples will then go to a specialized laboratory at the Johnson Center, where they will be safely stored and stored. The landing of the OSIRIS-REx mission pod will also be closely analyzed to optimize future similar deliveries of space material. “We’re not predicting anything we wouldn’t normally predict, but there will be a lot of eyes on our little corner of the desert this fall,” and Nelson admits, adding: “This creates a little more pressure than usual.
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2023-09-21 22:11:35
#delivery #material #planet #Bennu #Earth #approaching
