The Complete Book of Spaceflight: From Apollo 1 to Zero Gravity

SIRTF (Space Infrared Telescope Facility)
The fourth and final element in NASA’s Great Observatories
Program; the other three are the Hubble Space
Telescope, Chandra X-Ray Observatory, and Compton
Gamma-Ray Observatory. SIRTF’s cryogenically cooled
optical system will enable scientists to peer through the
dust clouds that surround many stars and will thus provide
a tool for studying the birth of planets. The observatory
will also help scientists explore the origin and
evolution of objects ranging from the Milky Way to the
outer reaches of the universe. SIRTF is scheduled for
launch in January 2003.
Skylab
See article, pages 378–380.
Skylark
A British sounding rocket program that originated in
1955, when the Ministry of Supply announced that the
Royal Aircraft Establishment and the Rocket Propulsion
Establishment would develop a rocket in time for the
International Geophysical Year in 1957. The first Skylark
was designed for economy, with no guidance system
and with launch towers built from spare parts of army
bridges. Its maiden launch on February 13, 1957, from
Woomera, Australia, was followed by two test flights and
then, in November 1957, the first operational mission
carrying scientific experiments. Over the years different
versions evolved, including a two-stage Skylark in 1960.
The rocket went international, being used by ESRO
(European Space Research Organisation) from 1964 to
1972 and by Germany from 1970. Although the British
Skylark program ended in 1979 after 266 launches and
the rocket is no longer manufactured, enough of Skylark
7s remain in stock for ESA (European Space Agency) to
continue launches of Britain’s most successful rocket into
the early part of the new century.
Skylon
A British design for a space plane intended to improve
upon that of HOTOL. It stems from the work of engineers
at Reaction Engines, a company formed in the early
1990s to continue work on HOTOL after the project was
officially cancelled. Reaction Engines were not allowed
to use the HOTOL RB454 engines, as they were still classified
top secret. A new engine was designed called
SABRE (Synergic Air Breathing Engine), which would
use liquid hydrogen and air until Skylon reached Mach
5.5, then switch to an onboard supply of liquid oxygen
for the final ascent to orbit. Skylon would be constructed
from carbon fiber, with aluminum fuel tanks and a
ceramic aeroshell to protect the craft from the heat of
reentry. A payload bay measuring 12.3 by 4.6 m would
Slayton, Donald Kent “Deke” 377
allow the payload to use standard air transport containers,
increasing ease of use. Skylon could take 12 tons of
payload to an equatorial orbit, or 9.5 tons to the International
Space Station. Unlike other comparable projects,
Skylon is intended to be run by commercial companies
rather than government space agencies, resulting in a
design similar to that of a normal aircraft with a vehicle
turnaround of only two days between flights, rather than
several weeks, as with the Space Shuttle. Operating on a
commercial basis could also reduce the price of launches
from $150 million for a 2- to 3-ton satellite to $10 million
for all cargo. Eventually, costs could fall to allow a
passenger seat to cost only $100,000, opening the way for
regular space tourism. Reaction Engines envisage that by
2025 there could be several companies operating Skylons
from specially constructed equatorial spaceports. In 1997,
Skylon was considered by ESA (European Space Agency)
for the FESTP (Future European Space Transportation
Project). More recently, it has been suggested that Skylon
could win the X-Prize, a sum of $10 million for the first
team to send a passenger into space. Reaction engines
have recently been attempting to put together a consortium
of aerospace companies to fund the Skylon project.
Skynet
A British military satellite communications network
developed with American assistance. With the launch of
Skynet 1A in 1969, Britain became the third entity after
the United States and Intelsat to orbit a geostationary
satellite. Skynet 1B, launched in August 1970, was
stranded in a transfer orbit when its apogee kick motor
failed to fire. Then Skynet 1A failed prematurely, and it
was not until 1974 that the first Skynet 2 was launched.
Unfortunately, this too was stranded in a useless orbit.
Skynet 2B, however, was successfully placed in an orbit
over the Indian Ocean at 42° E and, remarkably, was still
working 20 years later. Skynet 3 was never developed, and
the next launch was the first of the Skynet 4 series in
1988. Skynet 4, with an on-orbit mass of 800 kg, has one
experimental EHF (extremely high frequency) channel,
two UHF (ultrahigh frequency) channels, and four
X-band channels. The fifth and last Skynet 4, which
replaced Skynet 4C, was launched by an Ariane on February
26, 1999. The first Skynet 5 is expected in 2005.
Skyrocket
See Douglas Skyrocket.
Slayton, Donald Kent “Deke” (1924–1993)
One of the original Mercury Seven astronauts selected
in 1959, and the only one not to make a Mercury flight.
He did, however, fly on the Apollo-Soyuz Test Project
(continued on page 381)