Launch from the Baikonur Cosmodrome and
landing 300 km north of Dzheskasgan / 30 km southwest of Arkalyk.
The
Soyuz 16 mission was the
final rehearsal and
first manned mission in a program which culminated in the
Apollo-Soyuz (ASTP)
mission seven months later.
Main goals of the mission were check-out of
the
Soyuz space craft's on-board systems which had been
modernized to meet the requirements of the 1975 joint flight in accordance with
the programme of the Soviet-United States experiment; conduct of scientific and
technical investigations.
Early concepts for a joint flight included
docking a
Soyuz craft to the American Skylab space station, or
an Apollo vehicle docking with a
Salyut space station. Once the Americans abandoned
their Skylab station in 1974, the Apollo-
Salyut concept seemed to be the logical choice, but
since the Soviets had started to develop a universal docking adapter for the
mission and feared having to publicly reveal details of their military-focused
Salyut missions, the two powers opted to link a
Soyuz spacecraft with an Apollo
spacecraft.
During the flight, cosmonauts Anatoli
Filipchenko and Nikolai
Rukavishnikov tested the androgynous docking system to be
used for the
ASTP
mission by retracting and extending a simulated 20 kg American docking
ring.
The crew also tested modified environmental systems, new solar
panels and improved control systems, as well as a new radar docking system. The
air pressure was reduced from 760 mm to 540 mm and oxygen raised from 20% to
40% to test reducing the planned transfer time to Apollo from two to one hour.
On December 07, 1974, the docking ring was jettisoned with explosive bolts to
test emergency measures if the capture latches got stuck during the
ASTP
flight.
From launch to landing the flight of
Soyuz was nearly perfect, and the results of the test
of life support, docking, antenna deployment, and ground control systems were
excellent.
The
Soyuz spacecraft is composed of three elements
attached end-to-end - the Orbital Module, the Descent Module and the
Instrumentation/Propulsion Module. The crew occupied the central element, the
Descent Module. The other two modules are jettisoned prior to re-entry. They
burn up in the atmosphere, so only the Descent Module returned to Earth.
The
deorbit burn lasted 188 seconds. Having shed two-thirds of its mass, the
Soyuz reached Entry Interface - a point 400,000 feet
(121.9 kilometers) above the Earth, where friction due to the thickening
atmosphere began to heat its outer surfaces. With only 23 minutes left before
it lands on the grassy plains of central Asia, attention in the module turned
to slowing its rate of descent.
Eight minutes later, the spacecraft was
streaking through the sky at a rate of 755 feet (230 meters) per second. Before
it touched down, its speed slowed to only 5 feet (1.5 meter) per second, and it
lands at an even lower speed than that. Several onboard features ensure that
the vehicle and crew land safely and in relative comfort.
Four parachutes,
deployed 15 minutes before landing, dramatically slowed the vehicle's rate of
descent. Two pilot parachutes were the first to be released, and a drogue chute
attached to the second one followed immediately after. The drogue, measuring 24
square meters (258 square feet) in area, slowed the rate of descent from 755
feet (230 meters) per second to 262 feet (80 meters) per second.
The main
parachute was the last to emerge. It is the largest chute, with a surface area
of 10,764 square feet (1,000 square meters). Its harnesses shifted the
vehicle's attitude to a 30-degree angle relative to the ground, dissipating
heat, and then shifted it again to a straight vertical descent prior to
landing.
The main chute slowed the
Soyuz to a descent rate of only 24 feet (7.3 meters)
per second, which is still too fast for a comfortable landing. One second
before touchdown, two sets of three small engines on the bottom of the vehicle
fired, slowing the vehicle to soften the landing.