Editing Viking program (section)

===Payload===
[[File:Viking2lander1.jpg|thumb|right|Image from Mars taken by the ''Viking 2'' lander]]

==== Communications ====
Communications were accomplished through a 20-watt S-band transmitter using two [[traveling-wave tube]]s. A two-axis steerable high-gain parabolic antenna was mounted on a boom near one edge of the lander base. An [[omnidirectional antenna|omnidirectional]] low-gain S-band antenna also extended from the base. Both these antennae allowed for communication directly with the Earth, permitting Viking 1 to continue to work long after both orbiters had failed. A [[UHF]] {{Nowrap|(381 MHz)}} antenna provided a one-way relay to the orbiter using a 30&nbsp;watt relay radio. Data storage was on a 40-Mbit tape recorder, and the lander computer had a 6000-[[Word (data type)|word]] memory for command instructions.

==== Instruments ====
The lander carried instruments to achieve the primary scientific objectives of the lander mission: to study the [[biology]], chemical composition ([[organic compound|organic]] and [[inorganic]]), [[meteorology]], [[seismology]], [[magnetism|magnetic]] properties, appearance, and physical properties of the Martian surface and atmosphere. Two 360-degree cylindrical scan cameras were mounted near one long side of the base. From the center of this side extended the sampler arm, with a collector head, [[Sensor#Thermal|temperature sensor]], and [[magnet]] on the end. A [[Climate of Mars|meteorology]] boom, holding temperature, wind direction, and wind velocity sensors extended out and up from the top of one of the lander legs. A [[seismometer]], magnet and camera [[test target]]s, and magnifying [[mirror]] are mounted opposite the cameras, near the high-gain antenna. An interior environmentally controlled compartment held the [[biology]] experiment and the [[gas chromatography|gas chromatograph]] mass spectrometer. The [[X-ray]] [[fluorescence]] spectrometer was also mounted within the structure. A [[pressure]] sensor was attached under the lander body. The scientific [[Payload (air and space craft)|payload]] had a total mass of approximately {{convert|91|kg|abbr=on}}.