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Mars program
The Mars program was a series of unmanned
spacecraft launched by the Soviet Union between 1960 and 1973. The
spacecraft were intended to explore Mars, and included flyby
probes, landers and orbiters.
Early Mars spacecraft were small, and launched
by Molniya rockets. Starting with two failures in 1969, the heavier
Proton-K rocket was used to launch larger 5 tonne spacecraft,
consisting of an orbiter and a lander to Mars. The orbiter bus
design was likely somewhat rushed into service and
immature,[citation needed] considering that it performed very
reliably in the Venera variant after 1975. This reliability problem
was common to much Soviet space hardware from the late 1960s and
early 1970s and was largely corrected with a deliberate policy,
implemented in the mid-1970s, of consolidating (or "debugging")
existing designs rather than introducing new ones.
In addition to the Mars program, the Soviet
Union also sent a probe to Mars as part of the Zond program; Zond
2, however it failed en route. Two more spacecraft were sent during
the Fobos program. In 1996, Russia launched Mars 96, its first
interplanetary mission since the dissolution of the Soviet Union,
however it failed to depart Earth orbit.
The first Soviet attempts to send a probe to
Mars were the two Mars 1M spacecraft, which each had a mass of
about 650 kg. Both were launched in 1960 and failed to achieve
orbit. The spacecraft were dubbed Marsnik by the Western media.
Mars 1 was launched in 1962 but failed en route
to Mars. Two other Soviet launches at around the same time, Mars
2MV-4 No.1 and Mars 2MV-3 No.1 were 900-kilogram (2,000 lb)
spacecraft, however both failed to leave Earth orbit due to
problems with the upper stages of their carrier rockets.
Mars 2M No.521 and Mars 2M No.522, known in the
West as Mars 1969A and B, were heavier spacecraft with masses of 5
tonnes (4.9 LT; 5.5 ST). They were launched by Proton-K rockets,
and consisted of orbiters and landers similar to late Venera, and
Vega spacecraft.
The Mars 4M spacecraft; Mars 2 and Mars 3
missions consisted of identical spacecraft, each with an orbiter
and an attached lander, which became the first spacecraft to reach
the surface of Mars.
The orbiters' primary scientific objectives were
to image the Martian surface and clouds, determine the temperature
on Mars, study the topography, composition and physical properties
of the surface, measure properties of the atmosphere, monitor the
solar wind and the interplanetary and Martian magnetic fields, and
act as communications relays to send signals from the landers to
Earth.
Launch date/time:
Mars 2: May 19, 1971 at 16:22:44 UTC
Launch mass (including fuel):
Combined: 4650 kg
Orbiter: 3440 kg
Lander: 1210 kg
On-orbit dry mass: 2265 kg
Dimensions: 4.1 meters tall, 2 meters across (5.9 meters across
with solar panels deployed)
Mars 2 released the descent module 4.5 hours
before reaching Mars on November 27, 1971. The descent module
entered the Martian atmosphere at roughly 6.0 km/s at a steeper
angle than planned. The descent system malfunctioned and the lander
crashed at 45°S 30°W, delivering the Soviet Union coat of arms to
the surface. Meanwhile, the orbiter engine performed a burn to put
the spacecraft into a 1380 x 24,940 km, 18 hour orbit about Mars
with an inclination of 48.9 degrees. Scientific instruments were
generally turned on for about 30 minutes near periapsis.
Launch date/time:
Mars 3: May 28, 1971 at 15:26:30 UTC
Launch mass (including fuel):
Combined: 4650 kg
Orbiter: 3440 kg
Lander: 1210 kg
On-orbit dry mass: 2265 kg
Dimensions: 4.1 meters tall, 2 meters across (5.9 meters across
with solar panels deployed)
Mars 3's descent module was released at 09:14 UT
on December 2, 1971, 4 hours 35 minutes before reaching Mars. The
descent module entered the Martian atmosphere at roughly 5.7 km/s.
Through aerodynamic braking, parachutes, and retrorockets, the
lander achieved a soft landing at 45°S 158°W and began operations.
However, after 20 seconds the instruments stopped working for
unknown reasons, perhaps as a result of the massive surface dust
storms raging at the time of landing. Mars 3 lander still managed
to transmit a portion of the first picture of Martian surface.
Meanwhile, the orbiter had suffered from a partial loss of fuel and
did not have enough to put itself into a planned 25 hour orbit. The
engine instead performed a truncated burn to put the spacecraft
into a long 12 day, 19 hour period orbit about Mars with an
inclination thought to be similar to that of Mars 2 (48.9
degrees).
Both landers had a small Mars 'rover' on board,
which would move across the surface on skis while connected to the
lander with a 15-meter umbilical. Two small metal rods were used
for autonomous obstacle avoidance, as radio signals from Earth
would take too long to drive the rovers using remote control. Each
rover had both a densitometer and a dynamic penetrometer, to test
the density and the bearing strength of the soil. Because of the
demise of the landers, neither rover saw action.
The Mars 2 and 3 orbiters sent back a large
volume of data covering the period from December 1971 to March
1972, although transmissions continued through August. It was
announced that Mars 2 and 3 had completed their missions by August
22, 1972, after 362 orbits completed by Mars 2 and 20 orbits by
Mars 3. The probes sent back a total of 60 pictures. The images and
data enabled creation of surface relief maps, and gave information
on the Martian gravity and magnetic fields.
Kosmos 419 was launched on May 5, 1971. It
consisted of only an orbiter, and was intended to become the first
spacecraft to enter areocentric orbit, thereby beating the American
Mariner 8 and Mariner 9 spacecraft.
The Mars 4 and Mars 5 orbiters, launched in
1973, were designed to orbit Mars and return information on the
composition, structure, and properties of the Martian atmosphere
and surface. The spacecraft were also designed to act as
communications links to the Mars 6 and 7 landers. Like earlier
heavy spacecraft, they were launched by Proton-K rockets.
Launch date/time:
Mars 4: July 21, 1973 at 19:30:59 UTC
On-orbit mass:
Dry: 2270 kg
Fully-fuelled: 3440 kg
The Mars 4 orbiter reached Mars on February 10,
1974. Due to a flaw in the computer chip which resulted in
degradation of the chip during the voyage to Mars, the
retro-rockets designed to slow the craft into Mars orbit did not
fire , and Mars 4 flew by the planet at a range of 2200 km. It
returned one swath of pictures and some radio occultation data
which constituted the first detection of the nightside ionosphere
on Mars. It continued to return interplanetary data from solar
orbit after the flyby.
Launch date/time:
Mars 5: July 25, 1973 at 18:55:48 UTC
On-orbit mass:
Dry: 2270 kg
Fully-fuelled: 3440 kg
Mars 5 reached Mars on February 12, 1974 at
15:45 UT and was inserted into an elliptical 1755 by 32,555 km, 24
h 53 min orbit with an inclination of 35.3 degrees. Nearly
synchronized with the rotation of the planet, its two
phototelevision cameras could be commanded to take 12 pictures
during each close approach. The Vega camera used a wide area 52mm
lens with color filters, the Zulfar camera used a telescopic 350mm
lens and long-pass orange filter. Images were transmitted in a
rapid 220-line mode, and then selected pictures were retransmitted
at 880 or 1760 line resolution. Mars 5 collected data for 22 orbits
until a loss of pressurization in the transmitter housing ended the
mission. About 60 images were returned over a nine day period
showing swaths of the area south of Valles Marineris, from 5°N
330°W to 20°S 130°W.
The 1973 Mars launch window was
inefficient[clarification needed] and thus the Proton could not
deliver sufficient mass to the necessary trajectory to reach Mars,
as had been possible in 1971. To resolve this problem, two landers
were launched with orbiter type buses, but without fuel to enter
orbit. The Mars 4 and 5 orbiters, which had been launched
separately, were used to relay communications, and to complete
mission objectives which would have been completed by orbiters
launched with the Mars 6 and 7 spacecraft had they been flown.
Mars 6 successfully lifted off on August 5,
1973, into an intermediate Earth orbit on a Proton SL-12/D-1-e
booster and then launched into a Mars transfer trajectory. Total
fueled launch mass of the lander and bus was 3260 kg. It reached
Mars on March 12, 1974. The descent module separated from the bus
at a distance of 48,000 km from Mars. The bus continued on into a
heliocentric orbit after passing within 1600 km of Mars. The
descent module entered the atmosphere at 09:05:53 UT at a speed of
5.6 km/s. The parachute opened at 09:08:32 UT after the module had
slowed its speed to 600 m/s by aerobraking. During this time the
craft was collecting data and transmitting it directly to the bus
for immediate relay to Earth. Contact with the descent module was
lost at 09:11:05 UT in "direct proximity to the surface", probably
either when the retrorockets fired or when it hit the surface at an
estimated 61 m/s. Mars 6 landed at 23.90°S 19.42°W in the
Margaritifer Terra region of Mars. The landed mass was 635 kg. The
descent module transmitted 224 seconds of data before transmissions
ceased, the first data returned from the atmosphere of Mars. Much
of the data was unreadable due to a flaw in a computer chip which
led to degradation of the system during its journey to Mars.
Mars 7 successfully lifted off on August 9,
1973, into an intermediate Earth orbit on a Proton SL-12/D-1-e
booster and then launched into a Mars transfer trajectory. Total
fueled launch mass of the lander and bus was 3260 kg. It reached
Mars on March 9, 1974. Due to a problem in the operation of one of
the on-board systems (attitude control or retro-rockets) the
landing probe separated prematurely (4 hours before encounter) and
missed the planet by 1300 km. The early separation was probably due
to a computer chip error which resulted from degradation of the
systems during the trip to Mars. The intended landing site was 50°S
28°W. The lander and bus continued on into heliocentric orbits.
The Mars 4NM and Mars 5NM projects would have
seen heavier spacecraft launched by N1 rockets. They would have
deployed Marsokhod rovers onto the surface, and conducted sample
return missions. The N1 failed on all four of its test flights, and
was never used to launch any Mars spacecraft..
Mars-2 and Mars-3
The Mars program was a series of Mars unmanned
landers and orbiters launched by the Soviet Union in the early
1970s.
The Mars 2 and Mars 3 missions consisted of
identical spacecraft, each with an orbiter and an attached lander;
they were the first human artifacts to impact the surface of Mars.
They were launched by Proton K heavy launch vehicle with a Block D
upper stage.
Launch Date/Time:
Mars 2: 1971-05-19 at 16:22:44 UTC
Launch mass (including fuel):
Combined: 4650 kg
Orbiter: 3440 kg
Lander: 1210 kg
On-orbit dry mass: 2265 kg
Dimensions: 4.1 meters tall, 2 meters across (5.9 meters across
with solar panels deployed)
The orbiter engine performed a burn to put the
spacecraft into a 1380 x 24,940 km, 18 hour orbit about Mars with
an inclination of 48.9 degrees. Scientific instruments were
generally turned on for about 30 minutes near periapsis
The orbiter primary scientific objectives were
to image the Martian surface and clouds, determine the temperature
on Mars, study the topography, composition and physical properties
of the surface, measure properties of the atmosphere, monitor the
solar wind and the interplanetary and Martian magnetic fields, and
act as communications relays to send signals from the landers to
Earth.
The Mars 2 orbiter sent back a large volume of
data covering the period from December 1971 to March 1972, although
transmissions continued through August. It was announced that Mars
2 had completed their mission by 22 August 1972, after 362 orbits.
The probe, combined with Mars 3, sent back a total of 60 pictures.
The images and data revealed mountains as high as 22 km, atomic
hydrogen and oxygen in the upper atmosphere, surface temperatures
ranging from -110 °C to +13 °C, surface pressures of 5.5 to 6 mbar
(0.55 to 0.6 kPa), water vapor concentrations 5000 times less than
in Earth's atmosphere, the base of the ionosphere starting at 80 to
110 km altitude, and grains from dust storms as high as 7 km in the
atmosphere. The images and data enabled creation of surface relief
maps, and gave information on Martian gravity and magnetic
fields.
The lander crashed on the Martian surface and was lost.
The Mars 2 descent module was mounted on the
bus/orbiter opposite the propulsion system. It consisted of a
spherical 1.2 m diameter landing capsule, a 2.9 m diameter conical
aerodynamic braking shield, a parachute system and
retro-rockets.
The entire descent module had a fueled mass of 1210 kg, the
spherical landing capsule accounting for 358 kg of this. An
automatic control system consisting of gas micro-engines and
pressurized nitrogen containers provided attitude control. Four
"gunpowder" engines were mounted to the outer edge of the cone to
control pitch and yaw.
The main and auxiliary parachutes, the engine to initiate the
landing, and the radar altimeter were mounted on the top section of
the lander. Foam was used to absorb shock within the descent
module. The landing capsule had four triangular petals which would
open after landing, righting the spacecraft and exposing the
instrumentation.
The lander was equipped with two television cameras with a 360
degree view of the surface as well as a mass spectrometer to study
atmospheric composition; temperature, pressure, and wind sensors;
and devices to measure mechanical and chemical properties of the
surface, including a mechanical scoop to search for organic
materials and signs of life. It also contained a pennant with the
Soviet coat of arms.
Four aerials protruded from the top of the
sphere to provide communications with the orbiter via an onboard
radio system. The equipment was powered by batteries which were
charged by the orbiter prior to separation. Temperature control was
maintained through thermal insulation and a system of radiators.
The landing capsule was sterilized before launch to prevent
contamination of the martian environment.
The descent module separated from the orbiter on
27 November 1971 about 4.5 hours before reaching Mars. After
entering the atmosphere at approximately 6 km/s, the descent system
on the module malfunctioned, possibly because the angle of entry
was too steep. The descent sequence did not operate as planned and
the parachute did not deploy. Mars 2 was the first manmade object
to reach the surface of Mars. The landing site is unknown.
Mars 2 lander had a small 4.5 kg Mars 'rover' on
board, which would move across the surface on skis while connected
to the lander with a 15-meter umbilical. Two small metal rods were
used for autonomous obstacle avoidance, as radio signals from Earth
would take too long to drive the rovers using remote control. The
rover carried a dynamic penetrometer and a radiation
densitometer.
The main PROP-M frame was a squat box with a
small protrusion at the center. The frame was supported on two wide
flat skis, one extending down from each side elevating the frame
slightly above the surface. At the front of the box were obstacle
detection bars.
The rover was planned to be placed on the
surface after landing by a manipulator arm and to move in the field
of view of the television cameras and stop to make measurements
every 1.5 meters. The traces of movement in the martian soil would
also be recorded to determine material properties.
Because of the demise of the lander, the rover
never saw action.
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