OrbitalHub

Credits: NASA/CSA

Canadian astronaut Chris Hadfield will take command of the station during the second half of his third space mission. Hadfield will launch aboard a Soyuz rocket in December 2012, and spend six months on the station as part of the crew of Expedition 34/35. He will return to Earth in a Soyuz capsule in June 2013.

Hadfield is the only Canadian to board the Russian Mir space station, in 1995, during his first space flight, while he served as Mission Specialist 1 on STS-74. He is also the first Canadian mission specialist and the first Canadian to operate the Canadarm in orbit.

His second space flight was onboard STS-100, where he served as Mission Specialist 1. STS-100 was the International Space Station assembly flight 6A, which delivered and installed the Canadarm-2 on the station. During this mission, Hadfield performed two spacewalks.

Chris Hadfield also served as Director of Operations for NASA at the Yuri Gagarin Cosmonaut Training Centre in Star City, Russia; as Chief of Robotics for the NASA Astronaut Office at the Johnson Space Center in Houston, Texas; as Chief of International Space Station Operations; and as the Commander of NEEMO 14, a NASA undersea mission to test exploration concepts living in an underwater facility off the Florida coast.

The official announcement was made by the Canadian Space Agency. Chris Hadfield’s biography is also available here.

NASA and ATK successfully tested a five-segment solid rocket motor. The motor, dubbed DM-2, is the largest and the most powerful solid rocket motor designed for flight. It is designed to generate up to 3.6 million pounds of thrust at launch.

Read more about the DM-2 test…

Credits: CNES

Since the launch of Sputnik-1, on October 4, 1957, some 4,600 launches have placed more than 6,000 satellites in orbits around Earth.

All these activities have created a cloud of particles orbiting the Earth, which is referred to as orbital debris.

The majority of these particles are fragments from explosions and collisions (such as the Chinese Fengyun-1 ASAT test in 2007, and the collision between Iridium 33 and Cosmos 2251 in 2009). Some of them are spent rocket stages and defunct satellites. The total mass in orbit has been estimated to 5,800 tons.

As the ejecta generated in explosions and collisions have a wide range of velocities, the evolution of the particle cloud following the event can evolve in ways that are sometimes hard to predict, as some of the particles can disperse into orbits that are dissimilar to the original orbits.

Credits: NASA

To make things more complicated, the particles comprising the orbital debris environment are quite hard to detect. Some of them are impossible to detect due to technological limitations (present equipment is capable of tracking only objects larger than 1 cm in diameter in low Earth orbit and larger than 50 cm in diameter in geosynchronous orbit) or simply because they have orbits that are out of the range of tracking stations (such as highly elliptical and high inclination orbits with the perigee situated deep in the Southern Hemisphere – the Molniya orbits).

Even if most of the particles orbiting the Earth at velocities in the range of 8-10 km/s (or 28,800-36,000 km/h) are less than 1 cm in size, the kinetic energies associated with impacts at orbital velocities make them a source of great concern.

Just to get a sense of the effects that even small particles with velocities in the order of 10 km/s can have on space structures, if we assume a density of 1 g/cm³, a particle as small as 0.1 mm can cause surface erosion, and a particle 1 mm in size can inflict serious damage. A 3 mm particle moving at 10 km/s has the kinetic energy of a bowling ball moving at 100 km/h. A 1 cm fragment has the kinetic energy of a 180 kg safe. It is easy to visualize the effects of an impact with such an object on an operational satellite or a space station parked in low Earth orbit.

To find out more about orbital debris you can visit the NASA Orbital Debris Program office website.

Flight engineers Douglas Wheelock and Tracy Caldwell Dyson removed the spare pump module from an external stowage platform and installed it on the S1 Truss. The EVA was performed on August 16, 2010, and lasted for 7 hours and 20 minutes.

Read more about Expedition 24…

Flight engineers Douglas Wheelock and Tracy Caldwell Dyson extracted the failed pump from the station truss and prepared the spare pump for future installation. The EVA was performed on August 11, 2010, and lasted for 7 hours and 26 minutes.

Read more about Expedition 24…

Spacewalkers were Douglas Wheelock and Tracy Caldwell Dyson. The astronauts are removing a failed cooling pump unit. During this EVA, they manage to disconnect the electrical and fluid connectors, but did not complete all the planned tasks. The EVA was performed on August 7, 2010, and lasted for 8 hours and 3 minutes.

Read more about Expedition 24…