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

178 Hale, William
Edward Hale The Brick Moon’s inhabitants signal in Morse
code by jumping up and down, while people on Earth throw
them books and other provisions.
and in an instant, with all our friends [those building the
moon and their visiting families], it had been hurled into
the sky!” Later, a German astronomer spots the new moon
in orbit, complete with its marooned and unscheduled
inhabitants—apparently adapting well to their new life.
Hale therefore manages to portray not only the first artificial
satellite but also the first space station. 152
Hale, William (1797–1870)
An English inventor who developed the technique of
spin stabilization. Even following William Congreve’s
work, the accuracy of rockets was not much improved.
The devastating nature of war rockets was not their accuracy
or power but their numbers. During a typical siege,
thousands of them might be fired at the enemy. All over
the world, rocket researchers experimented with ways to
improve accuracy. It was Hale who thought of the idea of
allowing the escaping exhaust gases to strike small vanes
at the bottom of the rocket, causing it to spin like a rifled
bullet in flight. 314
Hall-effect thruster
A small rocket engine that uses a powerful magnetic field
to accelerate a low density plasma and so produce thrust.
A radial magnetic field is set up between two concentric
annular magnet pole pieces. The interior volume surrounded
by the magnet is filled with a low pressure propellant
gas through which a continuous electric discharge
passes between two electrodes. The positive electrode is
upstream of the magnet pole pieces, and the negative
electrode is directly downstream. The axial electric field
developed between the electrodes interacts with the
radial magnetic field to produce, by the so-called Hall
effect, a current in the azimuthal direction. This current,
in turn, reacts against the magnetic field to generate a
force on the propellant in the downstream axial direction.
Although conceived in the United States, the Hall
thruster was developed into an efficient propulsion
device—the SPT (stationary plasma thruster)—in the
Soviet Union. See electromagnetic propulsion.
halo orbit
An orbit in which a spacecraft will remain in the vicinity
of a Lagrangian point, following a circular or elliptical
loop around that point. The first mission to take advantage
of such an orbit was SOHO (Solar and Heliospheric
Observatory).
Ham
A 44-month-old male chimpanzee launched onboard Mercury
Capsule No. 5 at 11:55 A.M. on January 31, 1961, for
a suborbital flight. He was named for the initials of
Holloman Aerospace Medical Center, New Mexico, where
the space chimps lived and trained, and also after the
commander of Holloman Aeromedical Laboratory, Lt. Col.
Hamilton Blackshear. Ham’s mission, known as Mercury-
Redstone 2, was launched from Pad 5/6 at Cape Canaveral.
Because of over-acceleration of the launch vehicle plus
the added energy of the escape rocket, a speed of 9,426
km/hr was reached instead of the 7,081 km/hr planned,
resulting in an apogee of 253 km rather than the intended
185 km. This meant that Ham was weightless for 1.7 minutes
longer than the 4.9 minutes scheduled. He landed 679
km downrange after a 16.5-minute flight. His peak reentry
g was 14.7—almost 3g greater than planned. The capsule
splashed down about 97 km from the nearest recovery vessel.
Tears in the capsule’s landing bag capsized the craft, and
an open cabin pressure relief valve let still more seawater