NASA plans to destroy the International Space Station. But here are the risks

NOTasa has announced plans for the International Space Station (ISS) to be officially decommissioned in 2031. After dozens of launches since 1998 have put the station in orbit, bringing it down will be a feat in itself – the risks are serious if things go wrong .

Nasa’s plans for the decommissioning operation will culminate in a fiery plunge into the middle of the Pacific Ocean – a place called Nemo tipalso known as the “spacecraft graveyard”, the furthest point from all civilization.

Finding Point Nemo will be the final step in a complex, multi-stage mission to transfer ISS operations to new commercial space stations and return the remaining structure safely to Earth.

Initially commissioned for a 15-year lifespan, the ISS has outlived all expectations. It’s already been in service for 21 years, and NASA has given the go-ahead for another decade, doubling its planned total time in orbit.

Objective of the ISS

The ISS has enabled a giant leap for science and collaboration across humanity, involving five different space agencies (United States, Russia, Europe, Canada and Japan). Modules and parts of the ISS were built incrementally by many different countries, only coming into contact for the first time in space.

The monumental conglomerate structure now spans the length of a football field and is the largest man-made object in space. It is visible to the naked eye from Earth as it completes its 16 daily orbits, passing 400 km above the Earth’s surface.

Research into the so-called microgravity environment from the ISS has resulted in breakthroughs in drug discovery, vaccine development and medical treatments over the past decade. The ISS also helps to monitor Earth’s ecosystems and natural disasters in real time. It is used to test future spacecraft technologies and to study the health effects of long-term spaceflight for the possibility of future human exploration of the solar system.

Despite the acceleration of onboard research, NASA has noticed signs of a slowdown in infrastructure and components. For each orbit around the Earth, the ISS is burned by solar radiation on one side and freezes on the other. These thermal extremes cause cyclical expansion and contraction that wears down the material. Space radiation chars the transparent glass on the solar cells that are used to power the station, and repeated docking and unhooking causes the structure to gradually degrade, eventually leading to its demise.

The increase in flying space junk also poses the risk of unforeseen and catastrophic destruction. In 2016, a speck of paint peeled off a window, and last year the ISS crew went on standby for evacuation when Russia wiped out a dead satellite with a missile, causing thousands of debris. pass in front of the station at 5 km per second. Despite this, NASA believes there is “strong confidence” in the station through the end of 2030.

The dismantling operation

While Nasa has pledged to maintain the station until 2030, its partner organizations have yet to formally sign on, meaning the final decision to deorbit will depend as much on politics as engineering.

If unforeseen degradation or damage occurs before official dismantling, a free-falling ISS presents serious dangers. In fact, it wouldn’t be the first space station fall from the sky. In 1979, Nasa’s Skylab station was not refueled in time and collapsed, spiraling out of control, leaving pieces of the station strewn across Australia. Although no one was hurt, this led to reforms and “design for death” guidelines.

The design for death is a important principle for the engineering of satellites and other space infrastructures in orbit. Objects that fall freely from orbit must disintegrate into small pieces to ensure that they pose no danger to people on the ground.

The ISS is too big to satisfy the design principle for vanishing, that’s why we need special ops for deorbit. Experts believe that if it were to collapse out of control in a metropolitan area, the worst-case scenario could be on the the scale of a “9/11 event”. However, this is highly unlikely.

As part of the planned and controlled de-orbit operation of the ISS, newly constructed modules will first detach from the main structure and remain in orbit to eventually recombine as parts of future space stations. The ISS will then be slowed down slightly by onboard thrusters, which will gradually lower its altitude in orbit over the course of a few months.

The remaining descent will be faster, but controlled by a series of spacecraft sent to tether and steer the structure as it begins to plunge towards Earth. Upon re-entering the atmosphere, the majority of the structure will burn up, but the remaining mass is expected to remain on a targeted course to its deep sea resting place.

A Russian space station has already been safely shot down in the same waybut the ISS is about four times larger, so an operation on this scale remains untested.

New era

Before its complete de-orbit in 2031, the ISS will first experience a transition phase to support the crucial scientific research currently being carried out and to form the basis of new industries in space.

Jeff Bazos’ Blue Origin recently announced plans to replace the ISS with the private space station. Other key players include Northropp Grumman and Axiom Space (in partnership with SpaceX) which have a contract to start building modules from the existing ISS as soon as 2024.

There are also plans for a Russian space station which will likely include modules detached from the existing ISS. Meanwhile China launched the first module from their independent Tiangong space station last year, and plan to complete its expansion in the coming months.

Currently, NASA and its partner agencies oversee the use of their jointly owned infrastructure and are consulted on operations due to their governance expertise. However, the times are changing and NASA is now buying seats on SpaceX-owned spacecraft. In the end, NASA will become just another customer of commercial operators.

This article was republished from The conversation. Read the original article here.


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