History
Many orbital expendable launchers are derivatives of 1950s-era ballistic missiles. Many see this as unfortunate because cost was not a major consideration in their design. A prime example of this is the Titan IV, probably the costliest per-unit launch vehicle in history (perhaps following the Space Shuttle).
On the other hand, a reusable launcher such as the Shuttle requires a heavier structure and a recovery system (wings, thermal protection system, wheels, etc.) that reduce payload capacity. The Shuttle additionally carries a crew (though not inherent to a reusable system) whose weight, supplies and life support systems further decrease payload capacity.
A Shuttle orbiter is a major national asset, and its high cost (far more than a single expendable launch vehicle) and presence of a crew require stringent "man rated" flight safety precautions that increase launch and payload costs. Only five orbiters were built, and the loss of two (Challenger and Columbia) significantly impacted the capacity and viability of the Shuttle program. Each loss also resulted in an extended hiatus in Shuttle flights compared to that following most expendable launch failures, each of which impacted only that model of launcher.
For these reasons it is generally agreed that the Space Shuttle has not delivered on its original promise to reduce the costs of constructing and launching payloads into orbit. The Shuttle was originally intended to replace expendable launchers in the launching of satellites, but after the loss of Challenger the Shuttle was reserved for previously planned missions and those requiring a crew.
Spacecraft launched by the Shuttle included several TDRSS communications relays heavily used by the Shuttle program itself, a series of commercial communication satellites, and the interplanetary probes Magellan, Galileo and Ulysses. Several classified military payloads were also carried.
Read more about this topic: Expendable Launch System
Famous quotes containing the word history:
“No event in American history is more misunderstood than the Vietnam War. It was misreported then, and it is misremembered now.”
—Richard M. Nixon (b. 1913)
“Most events recorded in history are more remarkable than important, like eclipses of the sun and moon, by which all are attracted, but whose effects no one takes the trouble to calculate.”
—Henry David Thoreau (1817–1862)
“The history of this country was made largely by people who wanted to be left alone. Those who could not thrive when left to themselves never felt at ease in America.”
—Eric Hoffer (1902–1983)