SpaceX and NASA plan to de-orbit the International Space Station (ISS) using a powerful version of the company's Dragon spacecraft, which will push the orbital outpost onto a precision atmospheric re-entry over an unpopulated ocean region.
Earlier this year, NASA announced that it had awarded SpaceX an $843 million contract to design and build a spacecraft with enough thrust to shift the over 400 ton orbital outpost into a trajectory that would see it fragment and burn up in Earth’s atmosphere. The space station is currently slated for destruction sometime after the year 2030, when it will have reached the end of its three-decade-long operational life.
In a recent NASA press conference, SpaceX outlined its plan to use its existing line of Dragon spacecraft as a basis for its ISS killer. The crewed and cargo versions of the Dragon spacecraft already have a tried and tested track record, having successfully completed a cumulative 42 missions to the ISS following the cargo variant’s maiden flight in December 2010.
With 6x more propellant and 4x the power of today’s Dragon spacecraft, SpaceX was selected to design and develop the U.S. Deorbit Vehicle for a precise, controlled deorbit of the @Space_Station https://t.co/GgtuplTwqQ pic.twitter.com/E23sS7CE4U
— SpaceX (@SpaceX) July 17, 2024
The de-orbit vehicle is set to be around three to four times more powerful than any preceding variant of the Dragon spacecraft, while carrying around six times the amount of usable propellant. The majority of the modifications will be made to the ‘trunk’ section stacked beneath the dragon capsule, which will be fitted with the overhauled propellant tanks, avionics, engines, thermal hardware and power supplies needed to complete the challenging mission.
Alongside the 16 ‘Draco’ thrusters used by the Dragon capsule to control its position in space, the aft-facing section of the trunk will house a further 30 engines, that will burn in groups of 22 - 26 to provide the 10,000 Newtons of thrust needed to shift the ISS.
NASA is planning to launch the modified Dragon roughly 1.5 years prior to the final de-orbit manoeuvres. Once the spacecraft docks with the ISS, the station’s orbit will be allowed to naturally deteriorate until it sinks from its operational height of around 250 km down to an altitude of 220 km above Earth’s surface.
Once the station crosses this threshold, the souped-up Dragon will perform a series of burns designed to push its ward into a final, safe re-entry trajectory, which will see it crash into the atmosphere over an unpopulated ocean region, which has yet to be determined.
“First the vehicle will perform orbit shaping burns to put the station in a low elliptical orbit, and then eventually it will perform a final re-entry burn to lower the perigee to intercept with Earth at the intended location,” explained Sarah Walker, SpaceX’s director of Dragon mission management.
Naturally, the crew will have been evacuated long before this takes place, though they will remain aboard over the course of the first six months following the spaceship’s arrival, as the station drifts inexorably back to Earth. “The thing that I think is most complex and challenging is that this burn must be powerful enough to fly the entire space station, while resisting the torques and forces caused by increasing atmospheric drag on the space station to ensure that it ultimately terminates in the intended location,” continued Walker.
Relatively little of the ISS is expected to survive its encounter with Earth’s atmosphere, including its iconic solar pannels. However, the hardy debris that does endure – which could range in size between a microwave to a small sedan – will likely rain down in a narrow strip of ocean some 2,000 km in length. Sadly, there will only be limited opportunity to save parts of the station for future generations to appreciate.
“There’s some little things up on ISS that I think we’ll probably want to bring home on the last cargo Dragon that comes down,” said Ken Bowersox, associate administrator at NASA’s Space Operations Mission Directorate. “I can’t see us affording any dedicated missions right now, but for example the ships bell, logs, maybe some panels that have patches on them, some display items.”
The Passing of a Giant
In November 1988, a Russian Proton rocket made history when it launched the first Zarya Control Module module of the ISS into orbit. It would take a decade and over 30 missions to complete construction of the orbital outpost, which to this day remains the largest human-made structure ever constructed beyond the atmospheric confines of Earth.
Since the year 2000, the outpost has played host to over 270 astronauts, who have worked off the Earth, for the Earth, completing thousands of research projects that have benefited our species and advanced scientific knowledge in countless ways. It has also served as a valuable olive branch encouraging co-operation between nations some of whome often find themselves as adversaries on the world stage.
The ISS is still in good health, with a half decade of valuable science stretching out ahead of it. However, its operational life is due to come to an end sometime beyond the year 2030, after which the ageing outpost must be disposed of safely, to prevent it from being smashed to pieces by orbital debris, which could pose a threat to future LEO spacecraft.
NASA is holding out hope that new commercial space stations will be ready for use to allow humanity uninterrupted access to near-Earth space by the time that the ISS comes to be decommissioned. The agency is also looking further afield in an attempt to extend our race’s influence to the Moon as part of the Artemis program, before finally moving on to place human boots on the surface of Mars.
For more space news, why not read up on how scientists have mapped the entrance of an ancient tunnel extending below the surface of the Moon, or find out about the brightest object ever observed in the known universe, which shines 500 trillion times brighter than the Sun.
Image credit: SpaceX, NASA
Anthony is a freelance contributor covering science and video gaming news for IGN. He has over eight years experience of covering breaking developments in multiple scientific fields and absolutely no time for your shenanigans. Follow him on Twitter @BeardConGamer
