On 5 May 1989, the Space Shuttle Atlantis released the Magellan probe into low Earth orbit.

A short while later, Magellan’s rockets fired, sending it towards the sun.

Magellan being deployed from the Space Shuttle Atlantis on 5 May 1989. Credit: NASA

Swinging around our star, it arrived at its destination 15 months later: the planet Venus.

Venus is in some respects the most Earth-like planet in the Solar System. It is a similar size to our planet, has a rocky surface and a thick cloudy atmosphere. However, it is much closer to the sun, and thanks to its atmosphere, experiences a powerful greenhouse effect.

The planet Venus, seen by Mariner 10. Credit: NASA (processing by Ricardo Nunes)

Surface temperatures there are well over 400 degrees Celsius, atmospheric pressure is similar to what submersibles experience a kilometre down into Earth’s oceans, and the ‘air’ of Venus’ atmosphere is full of sulphuric acid.

Exploration of Venus’ surface has been in the form of brief snapshots, taken in the few tens of minutes that landers survive the harsh conditions there. All the landers so far have been Soviet; UCL has a number of their photos in its Centre for Planetary Sciences’ image archive (with a selection available online in high resolution).

The surface of Venus seen by the Venera 13 probe. Credit: UCL RPIF

Observing Venus from space is less challenging – and less rushed.

Between 1990 and 1994, Magellan was able to study the planet’s surface at leisure from its position high above the atmosphere. Because of the thick clouds, its images had to be produced by radar rather than optical photography, so they are not in colour. But they are extremely sharp.

Here is one of these images, held in UCL’s archives:

One of Magellan’s radar images of Venus’ surface. (The image is squint in the original!). Credit: UCL RPIF

Most of the highly processed images from Magellan are produced by multiple passes of the spacecraft over the planet’s surface, building up a complete image of the surface. This particular picture, however, is incomplete, revealing how Magellan’s images are put together. The black stripes show the gaps between the strips observed during different orbits of the planet.

Also in UCL’s archives are some of the planning documents NASA produced as part of the mission, including this full map of the planet’s surface:

Planning chart for the Magellan mission. Click here for labelled image showing the location of the above radar map. Credit: UCL RPIF

 Links

• Centre for Planetary Sciences
• UCL Regional Planetary Image Facility
• Snapshots from Space History (online exhibition of images from the Centre for Planetary Sciences)
• UCL Physics & Astronomy
• UCL Earth Sciences
• UCL Museums & Collections

NASA’s New Horizons probe is flying past Pluto today, after years of travel. It is the first ever probe to visit the Pluto system. Here, Minna Orvokki Nygren (UCL Science & Technology Studies) describes a unique art-science collaboration commissioned by UCL & Birkbeck’s Centre for Planetary Sciences to celebrate the event.

Pluto and its moon Charon, seen by New Horizons last week. Photo: NASA

Pluto and Charon – A Planetary Waltz was composed in collaboration between composers Catherine Kontz and Minna Orvokki Nygren. The work was commissioned by the Centre for Planetary Sciences UCL/Birkbeck (CPS) and it received its premiere on the 24th of June 2015 at An Evening with the Planets event at the UCL by pianists Valentina Pravodelov and Kerry Yong.

The main organiser of the event, Professor Steve Miller’s support and enthusiasm towards the project were crucial in realising this new work.

The piece was inspired by two photographic plates that led to the discovery of Pluto in 1930 by amateur astronomer Clyde W. Tombaugh.

The discovery images of Pluto

These plates were used to devise the overall form for the musical work. The distance the bodies travelled across the sky and their relation to other bodies was reflected in the music. When seemingly further away from other celestial bodies, the warped “waltz” of Pluto and Charon, written in 5/4 time, takes over with its prominent bass line and thick chords.

A key aspect of the composition is its gestural dimension which the pianists take on during performance, such as switching seats with each other as in an “orbital ballet,” or the use of custom planetary mallets applied to the piano interior marking off specific movements in the piece.

Other features, such as the size, temperature, consistency and albedo of the bodies were also part of the compositional process. The dwarf planet Pluto being approximately twice the size of Charon is given a more powerful and majestic voice in the work, while its counterpart Charon’s music is lighter, slower and mysterious. The Kuiper belt’s chilly conditions are reflected in the piece by combining extremely high and low pitches of the piano, and giving them an ethereal resonance through the use of distinct pedalling.

• Listen to the music here

An illustrated score of Pluto and Charon was created to give the audience an opportunity to follow the movement of the bodies and the musical piece.

Illustrations from the score (© Minna Nygren, all rights reserved)

Related links

• Catherine Kontz
• Minna Orvokki Nygren