The International Space Station just got a little lighter. Astronauts relieved the space station of about 3,500 pounds of garbage before detaching Cygnus, a cargo spacecraft supplied by Orbital Sciences to aid the ISS.

Cygnus arrived at the station a month earlier, carrying 3,300 pounds of equipment and food. The spacecraft stayed attached to the ISS for a month before it was detached early on the morning of August 15, 2014. Before they detached the commercial cargo craft, astronauts filled it with garbage from the space station, 3,500 pounds in total. They let Cygnus go 260 miles over the continent of Africa, where it will safely burn up and disintegrate upon reentry to Earth.

Orbital Sciences sent Cygnus into space a month ago in July. They were contracted by NASA to make the cargo spacecraft to help repopulate the food supply at the ISS, and bring other supplies such as maintenance equipment for the space station, and science experiments.

One piece of science equipment that Cygnus brought to the space station was a group of nanosatellites that will be released into space starting next week. These tiny satellites will orbit in space, gathering images of the Earth in an attempt to help disaster relief efforts on Earth. These nanosatellites were sent by the Kibo Laboratory in Japan.

This was the second supply mission run by a Cygnus spacecraft under a NASA contract.

"All the best wishes," German spaceman Alexander Gerst told Orbital Science's flight controllers via radio.

The flight controllers on ground will guide the Cygnus spacecraft into a controlled re-entry where it will burn up. The members of the International Space Station are planning to record the way it burns up so that scientists on the ground can study re-entry to learn more for when the International Space Station eventually must come down in a decade or two. The Space Station loses height every day and can only stay in orbit as long as scientists from around the world continue to send cargo spacecraft containing altitude boosts to correct the drop, as well as maintenance equipment to keep it in good shape. The Space Station must eventually come down.

Orbital Science is still contracted for another six cargo missions to the International Space Station using Cygnus spacecraft. They were orignially contracted for eight missions, and have now fulfilled two of them.

The astronauts aboard the ISS face many challenges, like sleeping in space, and dealing with living for so long in a very cramped environment. To learn more about the International Space Station and the astronauts aboard it, check out NASA's website.