Jul 19, 2011 09:57 GMT  ·  By
This image shows space shuttle Atlantis pulling away from the ISS for the last time
   This image shows space shuttle Atlantis pulling away from the ISS for the last time

The space shuttle Atlantis undocked from the International Space Station (ISS) earlier today, marking the last time any orbiter does this. The event marked the end of the shuttles' presence in space, as a supporter of the ISS and other project. Atlantis is expected to land on Thursday, July 21.

The spacecraft undocked from the space lab on Tuesday, July 19, at 2:28 am EDT (0628 GMT). The hatches between it and the ISS were closed on Monday, but the STS-135 spent the night inside the shuttle, getting ready for departure.

The four members of the crew now have 2 days of space travel ahead of them, before finally being able to reenter Earth's atmosphere, and land at the Kennedy Space Center (KSC), in Florida, one final time.

During this time, they have a planned heat shield inspection to carry out. The goal is to determine whether Atlantis' ceramic tiles were in any way damaged during the orbiter's stay at the ISS.

After the data are sent back to Mission Control, the astronauts will have to wait for the analysis results. If everything in green-lighted, then Atlantis may reenter the atmosphere on Thursday, Space reports.

The shuttle launched on July 8 on its final mission to the ISS, which also marked the final mission of the American Space Shuttle Program (SSP). After more than 30 years of activity, the most ambitious endeavor in continuous human spaceflight will be no more.

“Atlantis departing for the last time. Thank you for your 12 docked missions to the International Space Station. We'll miss you guys. Godspeed, soft landing,” an Expedition 28 crew member said this morning, as the orbiter was pulling away.

“The International Space Station now enters the era of utilization. Like a proud parent, we anticipate great things to follow from the men and women who build, operate, and live there,” STS-135 Commander Chris Ferguson said.

“From this unique vantage point, we can see a great thing has been accomplished. Farewell ISS, make us proud,” the NASA astronaut went on to say. During this final mission, Atlantis spent 8 days,15 hours and 21 minute docked to the orbital outpost.

“After my shift tomorrow, we'll commend the crew and the mission to the care of the entry team. The emotions feel a bit more intense today than they felt back on flight day two or flight day three,” shuttle flight director Kwatsi Alibaruho said on Monday.

“Personally, I feel a great sense of honor and pride at being able to serve as a shuttle flight director. It's been an extraordinary program. I feel intense gratitude and I'm very humbled by it. My team have been absolutely fantastic, I couldn't be more proud of them,” he added during a briefing.