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

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An early series of Soviet spacecraft designed to fly
by, orbit, and land on Mars. None of the probes
was completely successful and most were almost total
failures. The Soviet Union also launched several other
spacecraft between 1960 and 1971 that were intended
to explore Mars but, in the wake of their failure, did not
acknowledge their true purpose (see Mars, unmanned
spacecraft). These included Marsnik 1 and 2, Sputnik
22 and 24, Zond 2, Cosmos 419, and Mars 1969 A
and B. Sputnik 22, an intended Mars flyby mission,
was launched at the time of the Cuban missile crisis in
1962. When fragments of the exploded spacecraft
showed up on the U.S. Ballistic Missile Early Warning
System radar in Alaska, there was momentary alarm
that a Soviet nuclear attack might be underway. Cosmos
419 had been intended to overtake Mariner 8,
scheduled for launch two days earlier, and so become
the first spacecraft to orbit Mars. In the event, Mariner
8 also failed, and the race to be first in Mars orbit was
won by Mariner 9. (See table, “Mars Series.”)
Mars 1
A flyby probe. On March 21, 1963, with the spacecraft
106 million km from home, communication was
lost, perhaps due to a malfunction in the probe’s orientation
system. The closest approach to Mars took
place on June 19, at a distance of about 193,000 km,
after which the spacecraft entered solar orbit.
Mars 2
A Mars orbiter and descent probe. Mars 2 released its
descent module—the first attempt to soft-land on the
Red Planet—4.5 hours before entering orbit on November
27, 1971. However, the descent system malfunctioned
and the lander crashed at 45° S, 302° W,
delivering the Soviet Union coat of arms to the surface.
Meanwhile, the orbiter engine performed a burn
to put the spacecraft into a 1,380 × 24,940 km, 18hour
orbit about Mars with an inclination of 48.9°.
Scientific instruments were generally turned on for
about 30 minutes near periapsis (orbital low point),
and data was sent back for several months.
Mars 3
Identical to Mars 2, except the Mars 3 orbiter also carried
a French-built experiment called Spectrum 1,
Mars
which measured solar radio waves in conjunction with
Earth-based receivers to study the cause of solar outbursts.
The descent module was released on December
2, 1971, about 4.5 hours before reaching Mars
and, through a combination of aerobraking, parachutes,
and retro-rockets, successfully soft-landed at
45° S, 158° W. However, 20 seconds later, its instruments
stopped working for unknown reasons. The
orbiter entered an elliptical, 11-day orbit about Mars
from which it sent back data for several months.
Mars 4
An intended Mars orbiter. The probe’s retro-rockets
failed to fire to slow the craft into Mars orbit, and it
flew by at a range of 2,200 km, returning just one
swath of pictures and some radio occultation data.
Mars 5
A Mars probe intended to enter Martian orbit and
comprehensively photograph the planet. The spacecraft
reached Mars on February 12, 1974, and was
inserted into a 1,760 ×32,586 km orbit. However, due
to computer chip failures, the orbiter operated for only
a few days, returning atmospheric data and images of a
small portion of the Martian southern hemisphere.
Mars 6
A Mars probe consisting of a flyby bus and a descent
module. Mars 6 reached Mars on March 12, 1974, and
the descent module separated from the bus, opened
its parachute, and began to fall through the Martian
atmosphere. As the probe descended, it transmitted
data for 150 seconds, representing the first data
returned from the atmosphere of Mars. Unfortunately,
the data were largely unreadable due to a flaw
in a computer chip, and, shortly after the retro-rockets
fired for landing, all contact was lost with the craft.
Mars 6 landed at about 24° S, 25° W in the Margaritifer
Sinus region.
Mars 7
A Mars probe consisting of a flyby bus and a descent
module. Mars 7 reached Mars on March 9, 1974, but
the landing probe separated prematurely and missed
the planet by 1,300 km.