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Mir:  The Russian space station "Mir" (Russian for "peace") was launched back in 1986; it has been in orbit ever since.  Several pieces, called "modules", have been added over the years, and it now consists of several modules docked together.

Mir has been occupied almost continuously since 1986.  Russian astronauts (called cosmonauts by the Russians) travel to and from Mir in small capsules, and often stay at Mir for months at a time.  There are usually two or three cosmonauts on Mir at any one time; their food and supplies are sent up to them in unpiloted capsules.  The record for the longest time in space is held by a Russian who spent 14 months (over a year!) on Mir without returning to Earth.  As part of the US-Russian program, a few US astronauts will also be spending months at a time on Mir (STS-81 will bring on these astronauts home.)

Shuttle-Mir Rendezvous and Docking:  Each time the space shuttle flies to Mir, the US (from Mission Control in Houston) and the Russians (from their own Mission Control in Kaliningrad, Russia) collaborate to plan the intricate rendezvous of the space shuttle with the orbiting Mir; the Shuttle must dock with Mir while the two are both traveling 17,500 miles per hour around the earth!

Mir is orbiting the Earth continuously. Its orbit is nearly a circle, about 250 miles above the surface of the Earth; the circle lies in a plane that makes an angle with the Earth's equator of 51.6 degrees (this angle is called the angle of inclination).  The shuttle must launch so that its orbit is in this same plane.  We will talk more about the implications of this for KidSat in chapter 6.

Once the Shuttle is launched into this plane, it must still catch up with Mir.  The shuttle's orbit height can be changed after launch by (briefly) firing its OMS engines.  In fact, the Shuttle actually launches into an orbit that is lower than Mir's orbit.  In doing so, it goes around the Earth faster than Mir does, and therefore slowly catches up to Mir; when it's nearly caught up, its orbit is raised to match Mir's. Mission Control plans the Shuttle's orbit so that it will catch Mir on the third or fourth day of the shuttle flight.

07/10/96
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