CAPE CANAVERAL, Fla. -- Three of the six crew members living aboard the International Space Station are scheduled to return to earth on Tuesday after 166 days in space.
Outgoing Expedition 36 space station commander Pavel Vinogradov handed over command of the orbiting outpost to fellow cosmonaut Fyodor Yurchikhin on Monday, paving the way for his crew's planned departure.
Russians Vinogradov and Alexander Misurkin along with American Chris Cassidy are due to board their Soyuz TMA-08M craft at about 4:00 p.m. EDT (GMT +4 hours) on Tuesday in preparation for the craft's hatch closure at 4:20 p.m.
The trio arrived aboard the space station in the same spacecraft on March 28.
They will leave behind Yurchikhin, NASA astronaut Karen Nyberg and Italian astronaut Luca Parmitano who will stay aboard the space station until their departure in November.
Cassidy, along with Luca, performed two spacewalks during his stay to prepare the orbiting outpost for an upcoming Russian research module this December. The second orbital walk in July was cut short when leaking water floated into Luca's helmet.
Based on the Russian mission control timeline, the Soyuz spacecraft will undock from the Poisk docking port at 7:35 p.m., and slowly back straight out to a distance a few hundred feet out before circling around the station and departing.
Vinogradov will then maneuver the Soyuz to a proper attitude to allow a section of the Soyuz to fall away prior to leaving orbit at 10:05 p.m. in what is know as a deorbit burn.
The smaller Soyuz will slam into earth's atmosphere about thirty minutes later.
As a fireball surrounds the crew during re-entry, temperatures of nearly 3,000 degrees Fahrenheit will light up the Soyuz heat shield. The craft's approach has to be so precise or else the Soyuz could either burn up if it's angle is too shallow, or even skip off the atmosphere if it's attitude is too high.
The atmosphere will then help slow the Soyuz during it's decent as three massive parachutes deploy a few minutes prior to landing.
As the red and white parachutes gently lower the craft toward a region near Dzhezkazgen, Kazakhstan, blue skies, light winds and temperatures near 65 degrees F will welcome the crew home after 5 ½ months in earth orbit.
Landing of the Soyuz on the deserts of central Kazakhstan is planned for 10:58:50 p.m., which will be 8:58 a.m. local time on Wednesday, and will be carried live on NASA TV.
Several sections of the United States will be able to view both the space station and the Soyuz craft after the undocking 260 miles above them with the naked eye.
NASA's Web site will allow viewers to look up the information for their hometown and the time the two vehicle will soar overhead.
Two weeks later, a new crew of three will lift-off from Kazakhstan aboard a new Soyuz bound for their new home in space.
(Charles Atkeison reports on aerospace, science and technology. Follow his updates via Twitter @AbsolutSpaceGuy and on Instagram @BlueAngels_7.)