NASA's OSIRIS-REx will release the asteroid sample capsule in September this year, with the goal of landing in the Great Salt Lake Desert, and the team is ready to meet the challenges during its descent and recovery. This September, after traveling a billion miles across the solar system, NASA's OSIRIS-REx spacecraft will make an extraordinary flyby of Earth. As it passes by, it will release a capsule the size of a mini-fridge containing pristine space rock samples collected from asteroids located between the orbits of Earth and Mars.
OSIRIS-REx collected a half-pound sample from the surface of asteroid Bennu in October 2020. The mission's sample return capsule will land with the help of a parachute on September 24, just like the training model shown in the August 30 test at the Department of Defense's Utah Test and Training Range in the desert outside Salt Lake City. Image credit: NASA/KeeganBarber
OSIRIS-REx - Origins, Spectral Interpretation, Resource Identification and Security - Regolith Explorer - is the first U.S. mission to collect samples from an asteroid. Scientists hope that the raw material it collected from the asteroid Bennu in 2020 - about half a pound of debris and dust from the asteroid's surface - will provide a window into when the sun and planets formed 4.5 billion years ago.
Getting Started Challenges and Preparation
Until then, the sample's protective chamber will withstand twice the temperature of lava and the second-fastest speed ever for a man-made object entering Earth's atmosphere. After entering the Earth's atmosphere at about 36 times the speed of sound, the capsule may eventually encounter wind, rain and other weather conditions as it approaches the surface. Whatever the weather, it will land in the Great Salt Lake Desert, an arid land known for its hot summer temperatures and salt flats, remnants of ancient lake beds covered in crusty salt deposits.
While much of the focus will be on the technical aspects of the spacecraft and landing module, teams of scientists and meteorologists will also be closely monitoring weather, which could significantly impact the recovery of the landing module.
OSIRIS-REx is NASA's first asteroid sample return mission. It was launched in September 2016 and embarked on a journey to explore a near-Earth asteroid called Bennu. The exciting finale of the mission will occur on September 24, 2023, when the capsule containing Bennu samples will land in the western Utah desert. Source: NASA
"Seven years ago, before we launched, the capsule had to be designed to account for all the weather conditions we thought Utah would have in September," said Eric Queen, a research engineer on the Entry, Descent and Landing (EDL) team at NASA's Langley Research Center in Hampton, Virginia.
While the rugged capsule is built to be impervious to objects like lightning and ice, "wind is probably our biggest concern every time you land under a parachute," said Mark Johnson, head of EDL analytics at Lockheed Martin in Littleton, Colorado. That's because wind speed and direction could affect where the capsule lands on the 36-mile by 8.5-mile (58 km by 14 km) target at the Department of Defense's Utah Test and Training Range southwest of Salt Lake City.
Desert conditions and restoration planning
Kenneth Getzandanner, head of OSIRIS-REx flight dynamics, said the landing area is considered a "safe, controlled area." "This is also the landing site for the Stardust mission, so there's a legacy."
A recovery team participates in a field exercise in preparation for retrieving the sample return capsule for the NASAOSIRIS-REx mission at the Department of Defense's Utah Test and Training Range. The sample was collected by NASA's OSIRIS-REx spacecraft from the asteroid Bennu in October 2020 and will return to Earth on September 24 for a parachute landing at the Utah Test and Training Range. Image credit: NASA/KeeganBarber
The OSIRIS-REx team also put a lot of thought into the conditions on the ground itself. Late summer is the desert's monsoon season, so heavy rains can saturate the muddy ground. If an off-road vehicle is needed to help the helicopter find and transport the capsule, the wet cement-like mud will make driving difficult.
"By the end of the monsoon season, we should have an idea of how much precipitation we've received and the condition of the salt flats," said Eric Nelson, a U.S. Army meteorologist supporting the mission. "A good indicator is Bonneville Speed Week, which is an annual August racing event." Since everything is going smoothly, "we probably won't run into problems."
In support of the OSIRIS-REx mission, the team will deploy weather balloons in the days leading up to landing. Disposable balloons can reach altitudes of around 60,000 feet (18,288 metres), about twice as high as commercial jets fly. They rise at 18 feet (5.5m) per second, transmitting data on temperature, humidity, pressure and wind before hurtling into the atmosphere. The mission will use these observations to estimate possible landing locations within that range.
A training model of the sample return capsule is seen during a live rehearsal in preparation for retrieving the sample return capsule from NASA's OSIRIS-REx mission, Tuesday, Aug. 29, 2023, at the Department of Defense's Utah Test and Training Range. Image credit: NASA/KeeganBarber
How will delivery take place?
The final leg of the capsule's long journey will begin when it separates from the OSIRIS-REx spacecraft before entering Earth's atmosphere above the West Coast about four hours later. The roughly 100-pound (45-kilogram) capsule traveling at hypersonic speeds will rely on a protected entry system that includes a heat shield made of lightweight ablative material invented at NASA's Ames Research Center in Silicon Valley, California, and designed to withstand extreme temperatures.
Radar and infrared tracking systems will track the capsule during its descent. As it flies east on the morning of September 24, several aircraft, including a high-altitude WB-57 research aircraft at NASA's Johnson Space Center in Houston, will use visual and thermal imaging systems to track its journey.
When the capsule deploys its drogue parachute within the training range, it will be traveling at approximately 1,150 mph (1,850 km/h). The round main parachute will open close to the ground to soften the landing. Unlike other designs, the rounded shape is less likely to be caught by breezes, increasing the capsule's resistance and stability as it descends. This reduces the chance of it being blown off course by the wind, which could make it harder to detect on the ground.
Once landed and recovered by a dedicated team, the samples will be transferred to a special laboratory at Johnson where they will be preserved and studied. The historic landing will also be studied to inform future space deliveries.
"We're not going to predict anything that we wouldn't normally predict, but there's going to be a lot of eyes on our little corner of the desert this fall. It's going to be a little more stressful than usual," Nelson noted.