NASA’s Mariner II and its Encounter with Venus

27th August 1962, which is 58 years ago from today, NASA had launched a spacecraft named Mariner II. This mission bears the credit of being the first successful spacecraft of the Mariner series and gave NASA its first planetary encounter. Mariner II flew past Venus in 1962 after an unsuccessful attempt and created a colorful history for the American Space Station. The two Venus Missions Mariner I (the predecessor to Mariner II) and Mariner II are together named as Mariner R Missions. Let us explore more about this historical feat achieved by the curiosity of mankind to know what is beyond Earth.

What we will explore

• Quick Facts About Mariner II
• A Background Check
• Mission Details
• Some Important Instruments of Mariner II
• Objectives of the Mission 
• Results Obtained by Mariner II
• Briefing Up 

Quick Facts About Mariner II

• Second in the Series of Mariner Mission
• Mission Operator: NASA, US
• Predecessor: Mariner I
• Date of Launch: 26 August 1962
• Place of Launch: Cape Canaveral LC-12
• Mission Type: Venus Flyby
• Manufacturer of the SpaceCraft: Jet Propulsion Laboratory
• Rocket used to Launch the SpaceCraft: Atlas LV-3 Agena-B
• Mission Duration: Four Months, Seven Days
• Closest to Venus on 4th December 1962

A Background Check

• Mariner II was a part of the popular Mariner Program operated by the American Space Agency NASA.
• The program worked from 1962 to 1973, launching a series of robotic interplanetary probes.
• The objective of the probes launched was to study the planets Mercury, Mars and Venus.
• Out of ten missions of the Mariner Program, seven were successful and Mariner II was one of them.
• The Mariner Program evolved into other space programs after 1973.
• The total cost of the Mariner Program was $554 million.
• The Predecessor of the Mariner II was Mariner I launched on 22 July 1962 with the same purpose of investigating Venus. The Mission had failed due to a software glitch which led to the malfunction of the instruction guidance system of the spacecraft.
• Sadly the mission had to be aborted by destroying the spacecraft after seconds. The objective of the probe was fulfilled by the successor, Mariner II.
• After its success, Mariner II was rendered defunct after which it occupied heliocentric Orbit.

Mission Details

• Jet Propulsion Laboratory of the California University is credited for designing the elaborate spacecraft Mariner II.
• Total weight of the spacecraft was 203 kilograms out of which only 18 kgs were allotted to equipment to carry out scientific experiments.
• It housed all the important equipment to conduct the scientific experiments, carry communications, data computing, encoding, timing and attitude control.
• An interesting fact is that it used the Sun and the Earth as references for attitude stabilisation.

Some Important Instruments of Mariner II

The Instruments installed in the mast of the spacecraft had a specific purpose. Each played an important role to fulfill the objective of a successful probe.

•  Microwave Radiometer: To measure the absolute temperature of the surface of Venus and its atmospheric details.
• Infrared Radiometer: To measure the temperature of the small surfaces of the planet. It had the capacity to measure temperatures as high as between 200 and approximately 500 K.
• Fluxgate Magnetometer: To measure the changes in the planetary and the interplanetary magnetic fields.
• Ionization Chamber with Geiger-Muller Tubes: To measure cosmic radiation which is of very high energy.
• Particle Detector: The instrument was provided by the University of Lova hence it also goes by the name Lova Detector. Its objective was to measure the low radiations on the surface of venus which included soft x-rays and ultraviolet rays.
• Cosmic Dust Detector: With an objective of measuring the flux of cosmic dust particles in space.
• A Solar Plasma Spectrometer: To measure Solar wind.

Objectives of the Mission ‘Mariner II’

After the failure of Mariner I, NASA took up the challenge to carry out another mission by the name Mariner II. The spacecraft was designed as the exact replica of Mariner I and yes it did fulfill the job which was assigned to it.

As mentioned in the official NASA site “ The objective of the Mariner II mission was to flyby Venus and return data on the planet’s atmosphere, magnetic field, charged particle environment and mass. It also made measurements of the interplanetary medium during its cruise to Venus and after the flyby.”

Results obtained by Mariner II

The Mariner II laid down the fundamentals of what we know today about the Earth’s twin ‘Venus’

• The spacecraft with a glimpse of the planet showed back to Earth that Venus was a very hot planet with an average temperature of 462-degree celsius.
• The Pressure exerted by the atmosphere of Venus was very high, spacecraft which landed on the surface of Venus were crushed in minutes upon arrival.
• Mariner II revealed that because of its slow movement Venus does not generate a magnetic field in spite of having a metal core.
• The spacecraft is also credited with the discovery of the planet’s movement about its axis which is opposite to the movement of Earth and all other planets in the Solar System.
• It also made  discoveries related to Interplanetary Space and NASA quoted, “ the solar wind streams continuously and the cosmic density is much lower than the near-Earth region”
• Earth received Mariner II’s last transmission on 3rd January 1963.

Briefing Up

All the efforts put in by the scientists of the American space Agency bore fruit when Mariner II turned out to be successful and answered the doubts. It gave a kick to a series of other missions to quench the never-ending curiosity of the never-ending space where we belong. Mariner V was the next mission to Venus which beamed colored photographs of the twin planet.