NASA And SpaceX Miscalculated The Risk Of Space Debris Returning To Atmosphere

NASA illustration (photo: x @nasa)

JAKARTA - NASA and SpaceX are currently under the spotlight after several incidents where debris from an international Space Station (ISS) support mission fell to Earth. In fact, engineers thought that all the disposable hardware would burn out during reentry and did not reach the Earth's surface.

Engineers from Aerospace Corporation, a government-funded research center in El Segundo, California, highlight the urgent need for more research into what happens when a spacecraft re-entrys out of control into the atmosphere. Currently, more objects are being launched into space than ever before, and this trend will continue as companies launch more constellations of satellites and heavier rockets.

The current urgent need is to do more research to really understand this whole process and be ready to accommodate new ingredients as well as a new operational approach that is happening faster, said Marlon Sorge, executive director of the Aerospace's Center for Orbital and Reentry Debris Studies. "Obviously, that's the direction for spaceflight."

Ideally, satellites or rocket bodies at the end of their lifetime can be directed to carry out controlled reentry into the atmosphere over a remote part of the ocean. However, this is often expensive as it requires extra fuel for de-orbit maneuvers, and in many cases, the spacecraft has no rocket booster at all.

In March, a fragment of a battery pack dumped from the space station broke through the roof of a house in Florida, which is a rare example of property damage on land caused by space debris.

In May, a 90-pound chunk of SpaceX Dragon spacecraft leaving the International Space Station crashed on the "glamping" resort property in North Carolina. At the same time, a home owner in a nearby town found pieces of material that also appears to have come from the same Dragon mission.

The incident follows the discovery in April of another nearly 90 pounds of Dragon capsules in an agriculture in the province of Saskatchewan, Canada. NASA and SpaceX later determined that the debris fell from orbit in February, and earlier this month, SpaceX employees came to the farm to take the ruins, according to CBC.

The wreckage from Dragon's spacecraft also crashed in Colorado last year, and a farmer in Australia discovered debris from Dragon capsules on its land in 2022.

Many Unknown

Debris from satellites and non-functional rockets has fallen to Earth since the early days of the space era. The metal fuel tank from the old satellite or rocket body often survives reentry and falls to the ground. Now more rockets and satellites are made of lighter materials, such as composites.

This is a type of material used on SpaceX's part of the Dragon spacecraft that has been found in various parts of the world over the past few years. Engineers are still studying how composites react to extreme conditions during reentry, where they are hit by heat of up to several thousand degrees and aerodynamic forces that can tear up spacecraft.

Not just material that goes into the composite, said Greg Henning, the manager of the debris and disposal department in the aware department of the Aerospace space situation. "This is how the composites are put together. There is always some kind of geometry, like wovenness or something like that, which can be unique from one manufacturer to another, even though the materials are the same."

"The orientation of the spacecraft when it falls into the atmosphere can also affect the possibility of its survival," said Henning.

"Does it rotate? Does it re-enter with a stable configuration? There are a lot of factors that affect what actually happens during the reentry," he told Ars. "This makes it even more complex to know if something will survive or not."

The ruins found in some of Dragon's spacecraft come from the back of the plane, an unstressed circular structure mounted behind the pressure crew's compartment. The crew's capsule has a heat shield to survive the entry and safely return astronauts or cargo to Earth. At the end of each mission, Dragon capsules release the back that is no longer needed before performing de-orbit maneuvers to land at sea with the help of a parachute.

This back then remains in orbit for weeks to months until the weak air drag in low-Earth orbit eventually drags it back into the atmosphere. The trajectories are out of control again and can only be predicted with accuracy for a few hours, even on reentry day, meaning debris could fall in various parts of the planet.

SpaceX and NASA, which oversee the contract for Dragon crew and cargo missions, do not expect any material from the back of Dragon to survive the reentry.

During the initial design, the back of Dragon's spacecraft was evaluated for breakup during reentry and is expected to completely burn out, NASA said in a statement. "Information from the debris recovery provides an opportunity for the team to increase the modeling of debris. NASA and SpaceX will continue to explore additional solutions as we learn from the debris found."

The Earth is a vast area, and nearly three-quarters of these planets are covered in water. It's rare that objects re-entering hit someone's structure or injure someone, and the falling space debris never kills anyone. According to the European Space Agency, the annual risk of someone being injured by space debris is less than 1 in 100 billion.

But without mitigation, that opportunity will only increase as more satellites are launched into space