Where No Man Has Gone Before, Part 2. By Bram Peeters.
Part 2: The 1970's
The Mariner program: Mariner 8 & 9
Mariner 8 and 9 were the third and final pair of Mars missions in NASA's
Mariner series of the 1960s and early 1970s. Both were designed to be the
first Mars orbiters, marking a transition in our exploration of the red
planet from flying by the planet to spending time in orbit around it.
Mariner 8 was to map 70% of the Martian surface and Mariner 9 was to study
temporal changes in the Martian atmosphere and on the Martian surface.
Unfortunately, Mariner 8 failed during launch on May 8, 1971. This forced
Mariner 9 to combine the mission objectives of both.
Mariner 9 was launched successfully on May 30, 1971, and became the first
artificial satellite of Mars when it arrived and went into orbit, where it
functioned in Martian orbit for nearly a year. Mariner 9 completed its final
transmission October 27, 1972.
Upon arrival, Mariner 9 observed that a great dust storm was obscuring the
whole globe of the planet. Ground controllers sent commands to the
spacecraft to wait until the storm had abated, the dust had settled, and the
surface was clearly visible before compiling its global mosaic of
high-quality images of the Martian surface. The storm persisted for a month,
but after the dust cleared, Mariner 9 proceeded to reveal a very different
planet than expected -- one that boasted gigantic volcanoes and a grand
canyon stretching 4,800 kilometers (3,000 miles) across its surface. More
surprisingly, the relics of ancient riverbeds were carved in the landscape
of this seemingly dry and dusty planet. Mariner 9 exceeded all primary
photographic requirements by photomapping 100 percent of the planet's
surface. The spacecraft also provided the first close-up pictures of the two
small, irregular Martian moons: Phobos and Deimos.
Cosmos 419
This launch was intended to be a Mars orbiting mission. It is widely
believed this spacecraft was launched with the primary purpose of overtaking
Mariner 8, which had been launched (unsuccessfully, as it turned out) two
days earlier, and becoming the first Mars orbiter. The spacecraft was
presumably similar to the orbiter section of the later Mars 2 mission, a
cylindrical shaped spacecraft 3 meters high with two solar panels extending
from the sides, two large dish antennae, on top of retro-rockets and fuel
tanks. It carried an instrument to measure solar radiation, which was
supplied by the French.
The spacecraft was successfully put into low Earth parking orbit, but a
failure due to a bad ignition timer setting (the timer, which was supposed
to start ignition 1.5 hours after orbit was erroneously set for 1.5 years)
caused the orbit to decay and the spacecraft re-entered Earth's atmosphere 2
days later on 12 May 1971. The mission was designated Cosmos 419.
Beginning in 1962, the name Cosmos was given to Soviet spacecraft which
remained in Earth orbit, regardless of whether that was their intended final
destination. The designation of this mission as an intended planetary probe
is based on evidence from Soviet and non-Soviet sources and historical
documents. Typically Soviet planetary missions were initially put into an
Earth parking orbit as a launch platform with a rocket engine and attached
probe. The probes were then launched toward their targets with an engine
burn with a duration of roughly 4 minutes. If the engine misfired or the
burn was not completed, the probes would be left in Earth orbit and given a
Cosmos designation.
The Mars probe program: Mars 2 - 7
In 1971, shortly after Cosmos 419 failed to launch, the Soviet Union
successfully sent Mars 2 and Mars 3, nearly a decade after the launch of
Mars 1, all part of the Mars probe program. The Mars 2 and 3 probes each
carried a lander, both arriving on Mars in 1971. The Mars 2 lander entered
Mars' atmosphere at too steep an angle, causing it to crash, and the Mars 3
lander functioned for only 20 seconds after landing. They were the first
human artifacts to touch down on Mars.
In 1973, the Soviet Union sent four more probes to Mars: the Mars 4 and Mars
5 orbiters and the Mars 6 and Mars 7 orbiter/lander combinations. Of the
four, only Mars 5 succeeded; it transmitted 60 images before suffering a
transmitter failure. Mars 6's lander transmitted data during descent but
failed on impact. Mars 4 and 7 both missed the planet.
