This Day in Space: 9 September

Launching a few weeks after its twin Viking 1, Viking 2 followed suit and flew as an orbiter-lander pair entering Mars orbit. The landers then separated from the orbiters and descended to the planet’s surface.

9 September 1975 – NASA’s Viking 2 spacecraft launched from Cape Canaveral, Florida, bound for Mars.  Carried aloft by a Titan-Centaur rocket, Viking 2 comprised an orbiter and a lander segment, same as its sister craft, Viking 1.

The trip to Mars took just shy of a year, arriving on 3 September 1976.  The lander segment touched down in Utopia Planitia, which is the largest known impact basin in the Solar System, covering a large swathe of Mars’ northern hemisphere.

The orbiter, meanwhile, sent back over 16,000 images of Mars and one of its two moons, Deimos, over a period of 22 months, before it had to be deactivated following a malfunction in its propulsion system.

Viking 2 lander operated for over three years, concluding on 11 April 1980 when its radioisotope thermoelectric-charged batteries failed.

The twin Viking missions brought us the first images from the surface of Mars, and provided the first direct measurements of the planet’s surface soil composition, as well as testing for signs which could indicate the presence of organic life.

This rocky panoramic scene is the second picture of the Martian surface that was taken by Viking Lander 2 shortly after touchdown on September 3, 1976, at 3:58 PM PDT (Earth received time)

This Day in Space: 6 August

6 August 2014 – One year ago today ESA’s Rosetta spacecraft rendezvoused with comet 67P/Churyumov–Gerasimenko out between the orbits of Mars and Jupiter, over 400 million kilometres from Earth.

As the comet’s gravity is so minimal – if you were standing on 67P’s surface you could easily throw a ball upwards faster than its escape velocity, IE it would never come back down again! – Rosetta couldn’t just insert into a normal elliptical orbit, but instead had to perform a series of triangular-shaped orbits, making periodic engine burns to gradually work its way down to an orbital height of around 30 kilometres a month later.

Artist impression of ESA’s Rosetta approaching comet 67P/Churyumov-Gerasimenko.
The comet image was taken on 2 August 2014 by the spacecraft’s navigation camera at a distance of about 500 km.
The spacecraft and comet are not to scale.

Image source: http://www.esa.int/spaceinimages/Images/2014/08/Rosetta_arrives_at_comet

This Day in Space: 5 August

5 August 2011 – NASA’s Juno spacecraft blasted off from Cape Canaveral aboard an Atlas V rocket, beginning a five-year journey to the Solar System’s largest planet, Jupiter.  The 3.6-tonne spacecraft is scheduled to arrive in July 2016.

The name ‘Juno’ isn’t an acronym or a reference to the Ellen Page/Michael Cera comedy movie.  In Roman mythology Juno was the wife of Jupiter:  When Jupiter drew a veil of clouds around himself to hide his mischief, Juno was able to peer through the clouds and reveal Jupiter’s true nature.  Similarly, the Juno spacecraft will look deep into Jupiter’s obscuring cloud cover – http://www.nasa.gov/mission_pages/juno/news/juno20110805.html.

The god Jupiter drew a veil of clouds around himself to hide his mischief, and his wife, the goddess Juno, was able to peer through the clouds and reveal Jupiter’s true nature.

The Juno spacecraft, safely enclosed in the payload fairing at the top of an Atlas V rocket, begins its journey to Jupiter with a spectacular midday launch.

Jupiter and Io photographed by the Voyager 2 probe on 9 July 1979.

1979: Voyager 2 made its closest approach to Jupiter on this day, passing within 570,000km of the giant planet’s upper atmosphere.

The twin Voyager spacecraft made numerous discoveries in the Jovian system, including active volcanoes on the moon Io (the first discovered beyond Earth), faint rings encircling the planet and previously unknown moons.

Wikipedia
NASA Voyager homepage
JPL Voyager homepage