The last of the Automated Transfer Vehicle missions is currently underway, bringing supplies to the International Space Station with fabulous style. Due to dock tomorrow, ATV-5 sneaking up on the station looks more like a watercolour than a photograph taken by an astronaut.
ATV-5 during a fly-under just 7 kilometers below the International Space Station on August 8th/9th. Image credit: Alexander Gerst/NASA
ATV-5, otherwise known as Georges Lemaître, is the fifth Automated Transfer Vehicle mission run by the European Space Agency. The ATV is the heavyweight cargo-carrying space tug servicing the ISS. While several other services carry supplies to the space station, the ATV has the largest cargo capacity, and boasts greatest power.
The space tug is strong enough to nudge the station into orbital corrections, helping it maintain its orbit or protecting it from debris. As the station regularly loses about 50 to 100 m altitude each day due to normal drag, visits from the ATV to boost it back up into a higher orbit are a welcome interruption of the slow decay. It's also a great tool for bumping the station out of the path of approaching space junk, avoiding collision with debris.
Although it sounds a bit ridiculous, one of the handiest things about ATV-5 is its flexibility for loading cargo. It can carry a diverse mix of cargo including food, fuel, water, and personal effects, but even more importantly, thanks to a special lift with a rotating platform, it can keep being loaded even after it is balanced atop the Ariane rocket. The capacity for last-minute additions means the packing list doesn't need to be finalized weeks in advance, and can respond to changes in circumstances for the crew.
After being shoved into orbit by an Ariane 5 rocket, ATV-5 has been making a rendezvous trajectory that best resembles one of those trace-the-wire coordination games for small children. It's scheduled to finally dock on August 12th, delivering supplies to the space station. The docking is guided by a high-precision navigation system.
Although astronaut Alexander Gerst will be on-hand to monitor every step of the way, during the ATV-4 mission, the navigation system was so accurate it lined up only 11 millimetres off of dead-center.
ATV-4 was just 11 mm off-center when docking with the ISS on 15 June 2013 Credit: ESA/NASA
Check out the full approach and mission plan in this strangely charming animation:
After unloading, ATV-5 will hang around the station for up to six months acting as storage. Finally, it will be loaded down with waste, then sent back to Earth to burn up in a destructive re-entry as a glorious streak of flame. This will be the shallowest re-entry yet for the ATV series, hopefully producing a blazing counterpoint to ATV-5's previously photogenic posing during the under-fly. Scheduled for a moonless night with an assortment of telescopes to track the burn, the presumably-fabulous observations will also serve a scientific function: this is a test-run for planning out how to eventually de-orbit the space station with minimal fuss when the time comes.
ATV-4, Albert Einstein, was very pretty when it burned up during destructive re-entry on November 2, 2013, but ATV-5 should be even more spectacular. Image credit: ESA
This will be the last mission in the ATV sequence, with the blazing re-entry serving as a swan-song not just for ATV-5, but for the entire series of spacecraft. The European Space Agency had to choose between continuing with a sixth incarnation of the same cocnept, or using the lessons learned to move on and produce something new. They chose to partner up with NASA for the Orion project, taking the technologies they've improved and focusing them towards human spaceflight.