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

366 Schirra, Walter (“Wally”) Marty, Jr.
on the first/second stage adapter ring were fired for
4 seconds. As well as maintaining the positive motion
of the rocket, this forced the second-stage fuel to the
bottom of its tanks in order to feed the engines—a socalled
ullage maneuver—and was the cue for the five J-
2 second-stage engines to ignite. Thirty seconds later,
the first/second-stage adapter ring fell away, and six
seconds after that, the escape tower was jettisoned.
The second-stage engines burned for 365 seconds
before the next separation took place. Four solidfueled
retro-rockets on the second stage fired to keep
the second and third stages from colliding. Then the
second stage began its drop into the Atlantic about
4,000 km from the launch site. At this point, the Saturn
V was traveling about 25,300 km/hr at an altitude
of 185 km. Two solid-fueled motors on the third-stage
aft skirt were fired briefly to settle the fuel, and, simultaneously,
the S-IVB third-stage J-2 engine fired up for
a burn of 142 seconds. This initial S-IVB burn carried
Apollo into a 190-km orbit at a speed of 28,200
km/hr. During two or three checkout orbits, the S-IVB
attitude control motors could be fired in sequence to
make any necessary on-orbit corrections. Following
these checkout orbits, the ullage motors were fired for
77 seconds to settle the fuel and provide forward
spacecraft momentum. Then the third-stage J-2
engine reignited for 345 seconds to achieve a speed of
40,000 km/hr and to place Apollo on a lunar trajectory.
The third stage separated from the CSM/LM
combination, and the third-stage ullage motors fired
for 280 seconds to move the S-IVB clear of Apollo.
Finally, the J-2 fired for the last time, using up its
remaining fuel and, depending on the mission profile,
sending the spent third stage toward either deep space
Schirra, Walter (“Wally”) Marty, Jr. (1935–)
(continued from page 362)
Flying an F3D night fighter, Schirra was the first to fire a
Sidewinder at a drone target—with almost disastrous
results. The missile went out of control and started to
loop around to chase the plane; Schirra’s response was to
make an even faster loop to stay on its tail. He flew the
Mercury capsule Sigma 7 to become the third American
in space, commanded Gemini 7, which made the first
space rendezvous, and commanded Apollo 7. 262
Schmidlap, Johann (sixteenth century)
A German fireworks maker and perhaps the first, in 1591,
to experiment with staging—a technique for lifting fire-
or a collision with the Moon. These intentional lunar
impacts were to enable seismometers placed on the
lunar surface by previous Apollo missions to detect
the resulting “moonquakes” and to tell scientists
about the Moon’s internal structure.
Although a two-stage version of the Saturn V was
used to place Skylab in orbit, the rocket was effectively
retired at the end of the Apollo program. During
its development, the Saturn V was expected to
become a workhorse booster of a planned Apollo
Applications space science program that would follow
the lunar landing missions, but this program never
materialized. In December 1976, NASA released components
of two remaining vehicles along with test articles,
which eventually enabled the completion of
three Saturn V displays.
Overall length: 110.8 m (Apollo), 101.7 m (Skylab)
Payload: 129,300 kg (LEO), 48,500 kg (Moon)
First stage (S-IC)
Size: 42 m (length); 10 m (diameter); 19.2 m
(fin-span)
Propellants: RP-1 and LOX
Total thrust: 33,360,000 N (Apollo); 34,300,000
N (Skylab)
Second stage (S-II)
Size: 24.8 m (length); 10 m (diameter)
Propellants: liquid hydrogen and LOX
Total thrust: 5,170,000 N (Apollo); 5,000,000 N
(Skylab)
Third stage (S-IVB)
Size: 17.9 m (length); 6.6 m (diameter)
Thrust: 1,030,000 N
works to higher altitudes. A large skyrocket (first stage)
carried a smaller skyrocket (second stage). When the large
rocket burned out, the smaller one continued to a higher
altitude before showering the sky with glowing cinders.
Although Schmidlap appears to have been the first to fly
staged rockets, priority for the idea may go to Conrad
Haas.
Schmiedl, Friedrich (1902–1994)
An Austrian civil engineer who, beginning in 1918, carried
out numerous experiments with solid-fueled rockets.
In February 1931, he began a postal service using remotecontrolled
rockets that landed by parachute to carry mail
between neighboring towns, primarily Schöckel and