Martian milestones

It's been an action-packed month for the Red Planet. We chart the course of three exciting missions – two in orbit and one on the surface.

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An image from NASA's Mars Curiosity rover shows the ‘Amargosa Valley’, on the boundary between the plains of Gale Crater and the layered slopes of Mount Sharp.

September has been a month of milestones on Mars, with two new orbiters arriving and NASA’s Curiosity rover finally tackling Mount Sharp, a rugged five-kilometre high mountain it has been heading for since July.

NASA's Mars Curiosity rover imagery shows strata exposed along the margins of the valleys in the ‘Pahrump Hills’ region at the foot of Mt Sharp. The formation is consistent with a water-rich environment. – NASA/JPL-Caltech/MSSS

Maybe the biggest news was India’s successful debut inter-planetary mission when its orbiter Mangalyaan arrived last week.

But the first orbiter to arrive at Mars this month, two days earlier than Mangalyaan, was NASA’s Maven spacecraft. Maven will study the Martian atmosphere – or more precisely lack of it. Its mission is to find how the atmosphere came to be stripped off, turning Mars from a warm, wet planet into a cold, dry one.

An artist’s concept of NASA's Mars Atmosphere and Volatile Evolution (Maven) spacecraft in orbit around the planet. – NASA/Goddard Space Flight Center

Maven stands for Mars Atmosphere and Volatile EvolutioN. Its findings could lead to a breakthrough in our understanding of the planet, 40 years after photographs from NASA’s Mariner 9, the first spacecraft to orbit another planet, proved that Mars once held oceans of water.

The first images from Maven using its Imaging Ultraviolet Spectrograph (IUVS). – NASA

What has never been explained, and Maven may help answer, is the great mystery of what turned Mars into the dry barren desert it is today.

While various surface rovers have been looking for water underground, Maven will look at whether water escaped into space by studying how the upper atmosphere of Mars interacts with the solar winds that eroded the Martian atmosphere.

Meanwhile in India, where once there had been reservations about whether the $74 million mission was worth the money, jubilation broke out over the country’s achievement. Well it might have. No one before – not the Americans, the Europeans or the Russians – succeeded on their first Mars shot.

Indian Prime Minister Narendra Modi said: “If our cricket team wins a tournament the nation celebrates. Our scientists’ achievement is greater.” When an Indian says something is better than cricket, you know he’s serious.

What’s more, the Indian mission cost a fraction of similar voyages (NASA’s recent Maven mission cost $671 million and even the film Gravity cost more, at around $100 million to make). That has led to hopes the country’s space program will pick up business launching other countries’ communications satellites.

An illustration of the Indian orbiter Mangalyaan, which arrived at Mars last week. – ISRO
The first picture from Mangalyaan, taken from a height of about 7300 km, was proudly displayed on the mission’s Facebook page. – ISRO

The Mangalyaan probe will now set about taking pictures of the planet and studying its atmosphere.

In particular, it is trying to detect methane, which could be an indicator of biological activity at or below the surface.

Mangalyaan is now one of five missions circling the planet. Apart from Maven they are Mars Odyssey (US), Mars Reconnaissance Orbiter (US) and Mars Express (Europe).

Down on the planet’s surface, NASA’s Curiosity rover has been making headway, too. It’s currently in the foothills of Mount Sharp at the centre of the Gale Crater.

A self-portrait of NASA's Mars rover Curiosity taken last year. – NASA/JPL-Caltech/MSSS

On Friday 26 September Curiosity drilled its first bore hole since May, extracting a sample from a rock at a location dubbed “Pahrump Hills”. Hopefully the chemistry of the sediment will give scientists insights into the planet’s environmental history.

Specifically, they will be looking for high silicon content in the Pahrump sample which would suggest once-abundant water.

This image from Curiosity’s Mars Hand Lens Imager shows the first sample-collection hole drilled in Mount Sharp, the layered mountain. – NASA/JPL-Caltech/MSSS

Earlier findings prove that the floor of the crater was criss-crossed by rivers and a lake billions of years ago – conditions scientists say could have supported micro-organisms.

The next months are critical for Curiosity as it climbs the rugged forbidding mountain over the so-called Murray Formation, which makes up the base layers of Mount Sharp.

A topographical view of the edge of the Gale Crater. The rover (marked with a star) was on its way to the ‘Pahrump Hills’, part of the ‘Murray Formation’ of layered rocks. – NASA/JPL-Caltech Univ. of Arizona

The higher it gets, the younger the sediments should be, until it comes to a point where Mars’ climate turned from wet to dry, which may help us understand what caused the dramatic transition.

The one-tonne rover has had a tough journey with rough terrain taking its toll on the vehicle’s metal wheels. NASA has had to pick its way carefully, changing course more than once.

Tough terrain has forced NASA scientists to pick their way carefully. The new route provides excellent access to many features in the Murray Formation. – NASA/JPL-Caltech/Univ. of Arizona

“It has been a long but historic journey to this Martian mountain,” said Curiosity Project Scientist John Grotzinger of the California Institute of Technology in Pasadena.

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