Spring 2004 Issue

Getting to the High Frontier

 By Tom Webb, WA9AFM

As you may have read in the article “AMSAT OSCAR-E Project, Spring 2004 Status Report,” by Rick Hambly, W2GPS, elsewhere in this issue, Echo is assembled and ready to fly. Building a satellite is just half the project. Once you have the construction finalized, the components integrated, and the vehicle certification complete, then you have to get it into space with a proper orbit. As you will soon see, this can be a very daunting task, including all of the factors that go into launching a satellite into space.

Location, Location, Location

As with real estate, location of a launch site is critical to the success of launch. At present, there are just over a dozen major launch sites around the world (see Table 14.8 of the Radio Amateur’s Satellite Handbook). When a satellite is launched, you want to take advantage of every possible factor to help the launch vehicle achieve escape velocity and reach orbit. To maximize this boost, the ideal launch site would be located on the equator, launching to the east, to take advantage of the Earth’s rotation.

The latitude of a launch site will also determine the inclination of the satellite’s orbit. For example, Kourou, French Guiana is only 5 degrees north of the equator, making it virtually a perfect location for geostationary satellites, which orbit in the equatorial plain—i.e., zero degrees inclination. Likewise, Plesetsk, Russia at 63 degrees north is the best spot to launch satellites destined for high elliptical (Molniya) orbit, typically 63 degrees. Echo will be launched from Baikonur Cosmodrome (a.k.a. Tyuratam), Kazakhstan, which is at 46 degrees north.

Another factor is open, uninhabited space east of the launch site. Although it has no impact on the boost that Mother Earth provides, if the launch isn’t successful, the neighbors might get upset when an Ariane/TitanIII/Dnepr LV comes crashing down in their back yard. Thus, most launch sites are at coastal locations, launching over open water, or in uninhabited areas.

Cape Canaveral is a prime example. At 28 degrees north latitude, an eastward launch carries the vehicle out over the Atlantic Ocean. There is a certain irony attached to Cape Canaveral. When Jules Verne penned his tale “From The Earth To The Moon” in 1866, his launch site was in Florida, as the “optimum location to fire a projectile at the Moon would have to be either 28 degrees north or south latitude.” Verne’s launch “vehicle” was a giant cannon. Considering that it would have generated “G” forces in the thousands, a human passenger would not have survived the launch, but then it did make for a good story.

Vandenberg Air Force Base in California, and thus located on the west coast, looks out over open ocean to the south and is ideal for launches of polar-orbit satellites (weather and special mission), which require a southerly launch.

The main engines of a Dnepr LV fire just as it clears the launch silo. The large, dark cylinder is the gas-generator that ejects the Dnepr from the silo prior to engine start; this is known as “cold launch,” which allows the silo to be reused. (Photo courtesy of Richard Hambly, W2GPS)

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