Life on Mars

When in 2003 the orbits of Mars and Earth brought them the closest together they had been for 60,000 years, both NASA and the European Space Agency (ESA) sent robotic missions to Mars. The ESA mission was named Mars Express; the NASA mission was named Mars Exploration Rover (MER). NASA already had a satellite, Mars Odyssey, in orbit around Mars. The missions were intended to find evidence of life on Mars, either in the past or the present .

Mars Express was an international collaboration, originally consisting of two orbiters and a lander. The orbiters were ESA’s Mars Express itself and the Japanese spacecraft Nozomi; Beagle 2 was the lander .

Mars Express was launched by a Russian four‑stage Soyuz/Fregat launcher, with the Fregat upper stage separating from the spacecraft after placing it on a Mars‑bound trajectory. Mars Express was mounted on the Fregat upper stage .

The spacecraft used its on‑board means of propulsion solely for orbit corrections and to slow the spacecraft down for Mars orbit insertion. Electrical power was provided by the spacecraft’s solar panels which were deployed shortly after launch. When Mars was at its maximum distance from the sun (aphelion), the solar panels would still be capable of delivering 650 watts which was more than enough to meet the mission’s maximum requirement of 500 watts, equivalent to just five ordinary 100 watt light bulbs!

When the spacecraft’s view of the sun was obscured by Mars during a solar eclipse, a lithium‑ion battery (67.5 amp hours), previously charged up by the solar panels, took over the power supply .

Five of the instruments on Mars Express (HRSC, OMEGA, PFS, ASPERA and SPICAM) were descendants of instruments originally built for the Russian Mars ’96 mission. Each of the seven orbiter instrument teams on Mars Express had Russian coinvestigators who contributed their intellectual expertise to the project .

The Japanese spacecraft Nozomi was intended to go into near equatorial orbit around Mars shortly after Mars Express entered polar orbit. Nozomi had been due to reach the Red Planet in October 1999, but was delayed by a problem with the propulsion system, so the two missions took the opportunity to collaborate .

They shared a common interest in the Martian atmosphere – Nozomi even carried a close relative of ASPERA, the instrument on Mars Express to study interactions between the upper atmosphere and the solar wind .

Measurements recorded simultaneously by both spacecraft from their different vantage points would provide an unprecedented opportunity to study such interactions, so the two missions agreed to a programme of joint investigations and to the exchange of coinvestigators between the instrument teams .

ESA’s Beagle 2 landed on Mars at about thesametime as NASA’s Mars Rover mission. The two space agencies made arrangements to use each other’s orbiters as back‑up for relaying data and other communications from the landers to Earth .

Mars Express also intended to use NASA’s Deep Space Network for communications with Earth during parts of the mission. US scientists played a major role in one of Mars Express’s payload instruments, MARSIS, and participated as co‑investigators in most other instruments .

Mars Express and Beagle 2 marked the beginning of a major European involvement in an international programme to explore Mars over the next two decades. Europe, the US and Japan are planning to send missions, but many more countries will be contributing experiments, hardware and expertise .

The Beagle 2 lander was built by a British team. Being small and light it did not have a propulsion system of its own, and had to be “carried” precisely to its destination. On 19 December 2003 Mars Express was on a collision course with Mars, at which point Beagle 2 separated from it. Mars Express then veered away to avoid crashing onto the planet by firing its thrusters to get away from the collision course and enter into orbit around Mars. This was the first time that an orbiter delivered a lander without its own propulsion onto a planet, and attempted orbit insertion immediately afterwards .

Unfortunately no signal from Beagle 2 was ever received although Mars Express sent back significant pictures and information from orbit. It is thought that the atmospheric conditions at the time Beagle 2 attempted to land resulted in it being destroyed upon impact .

On 24 January 2004 Dr John Murray of the Mars Express team stated:

Scientists are on the threshold of the most exciting discovery about humanity’s place in the Universe since Galileo and Copernicus proved that the Earth goes round the Sun.

The European Mars Express spacecraft has determined beyond reasonable doubt that water, the prerequisite for all forms of terrestrial life, still exists on the Red Planet, and that it once flowed in torrents across its surface.

These remarkable revelations about our celestial neighbour provide the most tantalising evidence yet that the miracle of life on earth may not be unique, even within the confines of the solar system.

Wherever water is found on the Blue Planet – from the tundra of Antarctica to the depths of the ocean floor – we know there is life. For life as we know it, we need water. Now we can be certain that this vital commodity is present, and may once have been abundant, on the surface of Mars.

It seems more probable than ever that the planet so long considered barren and inert, may once have supported life.

It would be no exageration to compare such a discovery to the Copernican revolution, which put paid to the notion that the Earth stood at the centre of the Universe, or the voyages of Columbus and Magellan, proving the world to be round. It would mean that life has arisen twice on planets separated by as little as 35 million miles. And if that is so, it is probably common throughout the Universe.

We are not quite there yet. Neither Mars Express, nor NASA’s Spirit and Opportunity rovers, are designed to test the soil and rock for the chemical evidence that would provide definitive proof. Indeed, the European Probe’s results make it more frustrating than ever that Beagle 2, the British lander that was sent to Mars specifically to search for life, remains incommunicado.

The evidence of water, in the form of ice, makes it yet more important that we refuse to give up and dispatch Beagles 3, 4 and 5 to the Red Planet to resume the search.

We should not hold our breath for intelligent Martian life. Anything we find there will be extremely primitive, hardy microorganisms that can cope with extreme cold and harmful ultraviolet rays. These can live under the most unlikely of conditions: the Apollo moon landings turned up microorganisms carried years before as passengers on an unmanned probe.

Martian life could be found in the form of fossils that died out long ago. Or it could survive in certain suitable zones. The search will be a little like opening a window on the Earth billions of years ago.

There are times when science is more like hearing a Beethoven quartet than poring over reams of numbers. Yesterday was one of those occasions.

To look at the pictures from Mars Express’s high‑resolution stereo camera was to see something so supremely beautiful that I had to remind myself it was science, not art. These images would not have looked out of place at the Royal Academy’s Summer Exhibition.

Yet they tell us so much. There can be little doubt that the vast channel of Reull Vallis was carved by flowing water. It has water deposition and erosion: there is no way it could be anything else. When we look at Valles Marineris, it is as if we are gazing on the canyons and mesas that are so familiar to us from the American South West. It is a landscape of desolation and grandeur, but one that might possibly have harboured life.

This voyage of discovery encompasses so many great aspects of human endeavour. Important scientific advances are being made. But it is also advancing the achievement of the human race.

On 27 January 2004 Professor Colin Pillinger, the chief scientist of Beagle 2, was interviewed in The Times. When the loss of Beagle 2 was described as a heroic failure, he said:

“I don’t want to be a heroic failure. We would still like to be a heroic success, and we’ve done enough – if we don’t find it this time – to merit a second chance.”

Mars Express had found direct evidence of water on Mars. When he was asked about it he said:

“None of us thought there wasn’t water on Mars. I’ve seen it in my own Martian meteorites. But this is not a discovery of water. It was a very elegant demonstration of it.”

Professor Pillinger became interested in space years before Sputnik went into orbit in 1957, his mind catapulted starwards by the BBC radio programme Journey into Space.

Professor Pillinger compared the ESA and NASA missions:

Sending up two probes at once doubled NASA’s chances of hitting Mars at the closest it will come to Earth for 60,000 years, but Spirit was a better bet than Beagle even if it had been flying solo. While it had 24 air cushions and retro rockets to break its fall, Beagle had just the two airbags. Pillinger points out that Mars Express, the European spacecraft on which Beagle hitched a ride, could not have carried cargo anything as heavy as that so blame the lightweight European space programme.

But if only the dream had come true! The great future that lies beyond Beagle is more glorious than anything the American Rovers can aspire to. While NASA is merely looking for water, a precondition for life, Pillinger sought life itself.

He explained to me how the origins of his quest lay in the 1976Viking mission to the planet, which concluded that there was no life there. NASA turned its back on Mars and scooted off to explore the rest of the universe. But Viking later provided chemists with evidence that some meteorites that had been found in the Antarctic were Martian. It was while Pillinger and other scientists were examining their gas content to see if it matched the Martian atmosphere that they found, to their immense surprise, that there were traces of carbonates in them – evidence of life. Controversial at first, this finding was gradually accepted, the only remaining doubt being the worry that the samples could have been contaminated. It was to banish this doubt that Beagle was sent to conduct the same geochemical experiments on Mars to find the chemical fossils of extraterrestrials.

Had things gone differently, by the middle of next month Pillinger might well have been able to announce that he had found the first proof of extraterrestal life.

NASA’s Mars Odyssey orbiter went into orbit around Mars during 2001, then in 2003 NASA launched another Mars exploration project called MER (Mars Exploration Rover). On 10 June and 7 July 2003 they launched spacecraft toward Mars, each spacecraft carrying a Mars Exploration Rover. Like the ESA Mars Express mission, the rovers were in search of answers about the history of water on Mars and were scheduled to land on 3 January and 24 January PST (4 January and 25 January UTC) .

The first rover landed on 4 January 2004. Called Spirit by NASA, it was a six‑wheeled vehicle about the size of a golf cart and was equipped to play the role of a geological explorer .

Spirit immediately transmitted a range of black and white images, including a sweeping panoramic of the Martian landscape, as well as a bird’s‑eye view of the rover with its solar panels fully deployed .

Mission science manager John Callas said:

“This just keeps getting better and better. The pictures are fantastic.”

The total cost of the MER project was £545 million .

When NASA’s first Mars Exploration rover landed on Mars, Mark Henderson, Science Correspondent of The Times reported:

NASA scientists controlling the Spirit rover, which landed on Mars on Sunday, have chosen its first destination: a 10‑metre‑wide (30ft) crater they have nicknamed “Sleepy Hollow”.

The circular depression, which can be seen clearly in panoramic pictures sent to Earth yesterday, has been singled out as the best place for Spirit to begin its search for evidence that Mars was once wet and habitable. The rover is likely to set off for the crater, named after an American horror story, as soon as it leaves its landing module early next week.

Steve Squyres, the mission’s chief scientist, said the images suggested that a meteor strike had probably created the crater. The impact is likely to have cut through layers of rock, excavating the planetary surface for the rover to explore.

“The science so far has been extremely focused on where to go after the egress,” Dr Squyres said. “It’s a circular depression, 30ft in diameter and about 40ft to 50ft away from the rover.

“It’s a hole in the ground, a window into the interior of Mars. It may have been an impact crater, largely filled with dust. You can see the rock is exposed on the far side.

“It’s a very exciting feature for us. It’s probably where we will go unless we see something better.

“The feature now has a name. We have all not been getting as much sleep as we’d like, so this feature is now named Sleepy Hollow.”

Spirit, which has a daily range of 20m (65ft), will use its rock abrasion tool to grind down the surface of boulders, before testing them with scientific instruments. It aims to establish whether Mars holds sedimentary rocks, which would offer evidence that the planet once flowed with water – a prerequisite for life.

Scientists believe that Gusev Crater, the region in which Spirit landed, might have held an ancient lake, making it a promising site for finding sediments.

Dr Squyres said yesterday that tests on four of the craft’s six key instruments had shown that they had survived Spirit’s hard landing on Mars, in which it bounced up to 14 times before coming to a halt.

His team was relieved that the sensitive Mossbauer spectrometer, which identifies iron isotopes in rocks, was working. Tests on the remaining instruments will begin today. Scientists were hoping last night to receive a colour high‑resolution panoramic picture from the rover, which would be by far the best image of Mars ever captured.

Dr Squyres said that they had received 12 thumbnail pictures showing that Spirit had taken the required photographs, which were being stored in the craft’s memory, awaiting the right opportunity to return them to Earth.

“We have acquired the image, the pictures are taken and on board Spirit, ready to be downlinked,” he said.

Earlier, the team successfully deployed the rover’s high‑gain antenna and pointed it to Earth, which will allow it to talk directly with mission control.

This will cut communication times to nine minutes, compared with more than an hour when signals are relayed through NASA’s twin orbiters, Mars Odyssey and Mars Global Surveyor.

Matt Wallace, deputy surface mission manager, said Spirit had taken pictures of the Sun’s position overhead to point the antenna in the correct direction.

“Just as the ancient mariners used sextants to locate themselves by shooting the Sun, we were successful at shooting the Sun using our pan‑cam,” he said. “It’s been another good day on Mars.”

On 16 January 2004, Mark Henderson reported:

NASA’s Spirit rover took its first spin on Mars yesterday, successfully driving the three metres from its landing platform to the planet’s surface. Engineers played “Who Let the Dogs Out?” on the mission control stereo as pictures showing two parallel tracks in the Martian dirt were beamed back to Earth, confirming that the golf‑cart‑sized robot had completed the most hazardous manoeuvre of its three‑month mission.

The 78‑second journey to the surface ended a 12‑day wait since Spirit’s landing at Gusev Crater on January 4, during which the rover had been unfolding itself, checking its systems and turning 115 degrees to line up with the most favourable exit ramp. It is now parked next to the lander, where it will stay for three days while scientists conduct experiments on nearby soil and rocks.

At the weekend, Spirit will set off on its first long drive, probably towards a crater approximately 250 metres away. If all goes well, the plan is then to turn right at the crater and head for the hills about 3km (1.9 miles) away.

The success, which scientists toasted with champagne, came the day after President Bush announced NASA budget increases of $1 billion (£549 million) a year to support efforts to establish a permanent Moon base and send a manned mission to Mars.

Charles Elachi, director of Nasa’s Jet Propulsion laboratory in Pasadena, California, which built and operates Spirit said: “Less than 24 hours ago, President Bush committed our nation to a sustained mission of space exploration. We at NASA move awfully fast. We have six wheels in the dirt. Mars is our sandbox and we’re ready to play and work.”

Though the first drive took just 78 seconds, at a speed of 4cm per second, Spirit then had to turn its main antenna towards Earth before it could confirm its new position and send back pictures. Scientists at mission control cheered as the good news arrived at 9.50 am GMT.

Russia could send a man to Mars at a tenth of the cost of American plans, according to one of Russia’s top space officials, Leonid Gorshkov, the chief designer of the state‑controlled Energia company, which built the core of the International Space Station and now wants to re‑enter the space race. “Technically, the first flight to Mars could be made in 2014,” Dr Gorshkov said.

Today Spirit’s science team will join European colleagues in an unprecedented experiment when Europe’s Mars Express orbiter flies directly overhead. Spirit will look up into the Martian atmosphere with its panoramic cameras and a thermal emissions spectrometer while Mars Express looks at the same portion from above with its instruments. Data from the spacecraft will be combined to create the most comprehensive picture yet of the atmosphere on Mars.

Spirit’s sister rover, Opportunity, is scheduled to land next Sunday at the Meridiani Planum region of Mars.

On 25 January 2004, a second NASA robotic probe landed on Mars and began to send back pictures. The next day Mark Henderson reported in The Times:

A dark and mysterious side to Mars that has never been seen before was revealed by NASA’s Opportunity rover yesterday in a remarkable series of pictures beamed to Earth within hours of its faultless landing.

The images of Meridiani Planum, where NASA’s second robotic probe touched down at 5.05 am, show a strange plain covered in fine‑grain maroon soil much darker than anything yet observed on Mars, and an outcrop of grey bedrock that could offer clues to the planet’s geological past.

These odd features are ideal for the rover’s mission – the search for evidence that the planet was once wet and suitable for life – and led one scientist to describe the landing site as “the promised land”.

The slabs of protruding rock could contain grey haematite, a form of iron oxide that is normally formed in the presence of water. They are the rover’s most likely first target. Meridiani Planum was chosen for Opportunity’s landing as orbiting spacecraft had picked up traces of the mineral in the region. Steve Squyres, the rover missions’ chief scientist, said that he was flabbergasted by the pictures, which look different from those taken by Opportunity’s twin, Spirit, at Gusev Crater.

“Opportunity has touched down in a bizarre, alien landscape,” he said. “I’m astonished. I’m blown away. It looks like nothing that I’ve ever seen in my life. Holy smokes, I’ve got nothing else to say.”

The rover’s textbook landing brightened the mood at NASA’s jet propulsion laboratory in Pasadena, California, where the team has been working furiously since Wednesday to diagnose and correct a potentially catastrophic fault aboard Spirit, which landed three weeks ago.

Engineers said that they had established the root cause of its problems and had stabilised the robot by switching off a malfuctioning memory system.

Even so, it may be three weeks or more before Spirit can resume scientific investigations, and the memory problem may prevent it from recovering full operational capacity.

Mission control had said that it could take 22 hours for Opportunity to make contact with Earth following its scheduled arrival at 5.05 am, but the rover sent signals within moments of landing. Scientists cheered, and were congratulated by Arnold Schwarzenegger, the Governor of California, and former Vice President Al Gore, who joined the vigil at the laboratory.

Sean O’Keefe, the NASA administrator, saluted his team for landing both rovers successfully, and for beating the “Mars jinx under which two thirds of all missions to the planet have failed. What a night,” he said as he broke open champagne for a second time in three weeks. “No one dared hope that both rover landings would be so successful.”

While Spirit landed on the base petal of its protective pyramidal shell, Opportunity landed on a side petal and had to be flipped into an upright position.

All the airbags that cushioned it on landing appear to have been successfully retracted. One of Spirit’s airbags refused to deflate properly forcing engineers to turn the rover 120 degrees before it could be driven away from the landing module.

British scientists will today begin one of their final attempts to find their missing Beagle 2 lander. The team has not tried to contact the probe for almost two weeks to try to force it into an emergency transmission mode.

On 27 January 2004, Mark Henderson reported in The Times:

NASA’s Opportunity Mars rover has landed in a small crater, to the delight of scientists who hope that it will provide a ready made window into the planet’s geological past.

The shallow crater, about 65ft across, was formed by a meteor impact, which has performed natural excavation work allowing the rover to peer below the Martian surface without having to dig.

Steve Squyres of Cornell University, lead scientist for the Mars rovers, said that the crater was ideal: big enough to be of great scientific interest but not so deep that the six wheeled robot would be stranded. “We have scored a 300 million mile interplanetary hole in one,” he said. The rover will spend at least a week unfolding itself before leaving its landing module.

British scientists have begun a post‑mortem examination into the failure of Beagle 2. Colin Pillinger, the mission’s chief scientist, said yesterday that his team accepted the probable loss.

Direct evidence that Mars was once awash with liquid water has been discovered for the first time, proving that life could once have existed on the planet and may still be there.

NASA scientists announced last night that the Opportunity rover had determined that the rocks of its Meridiani Planum landing site had been soaked in liquid water, the prerequisite of life on Earth.

The startling findings show unequivocally that at least part of the Red Planet has been wet and habitable in the past, with conditions suitable for living organisms to evolve and survive.

Steve Squyres, chief scientist for NASA’s rover mission, said that while the discovery does not prove that life had ever existed on Mars, it shows beyond doubt that it is a real possibility.

“The purpose of going to Mars was to see whether or not it was a habitable environment,” he said. “We believe that this place, in Meridiani Planum, at some point in time was habitable. That doesn’t mean life was there, but it is a place that was habitable at one time.”

James Garvin, NASA’s lead scientist for Mars exploration, said, “NASA launched the Mars Exploration Rover mission specifically to check whether at least one part of Mars ever had a persistently wet environment that could possibly have been hospitable to life. Today we have strong evidence for an exciting answer – ‘yes’.”

Observations from orbit, most recently from the European Mars Express spacecraft, have shown that frozen water exists at the Red Planet’s poles. Probes have also photographed geological features such as canyons and dried‑up beds that appear to have been carved by rivers, oceans and lakes.

Water, however, must exist in its liquid form to sustain life, and no direct evidence of this had been found before Opportunity’s investigations.

The conclusion that the rocks of Meridiani Planum, where Opportunity landed on January 25, were once underwater follows three weeks of meticulous experiments. “We’ve been attacking it with every piece of our hardware and the puzzle pieces have been falling into place,” Dr Squyres said.

Four separate pieces of evidence have combined to build a compelling picture. The alpha particle X‑ray spectrometer has found high concentrations of sulphate salts, which have to be dissolved in water to accumulate. The Mossbauer spectrometer has also found a mineral called jarosite, which is formed in the presence of water.

Physical features of the rock have provided important clues. Round particles known as “spherules”, which Dr Squyres likened to “blueberries in a muffin”, appear to have been formed by dissolved minerals. Holes known as “vugs” have been left by crystals of salt, laid down in briny water.

Some of the key discoveries came from analysis of a rock nicknamed El Capitan, after a rock formation in Yosemite National Park in California.

“Put the story together, and it is hard to avoid the conclusion that this stuff was deposited in liquid water,” Dr Squyres said.

Ed Weiler, NASA’s associate administrator for space science, said, “Opportunity has landed in an area of Mars where liquid water once drenched the surface. This area would have been a good, habitable environment.”

Scientists will have to wait, however, to find out whether this environment actually supported life. Neither Opportunity nor her sister rover, Spirit, carries the instruments needed to search for traces of living organisms. Britain’s Beagle 2 Mars probe, which was lost last year, did carry two experiments that would have been able to detect life.

The old theory about Canals on Mars was based on an optical illusion. Mark Henderson reported:

The question of whether water and life ever existed on Mars dates from the 17th century, when the Dutch astronomer Christiaan Huygens first identified light patches at the poles that appeared to be ice caps.

The notion, however, did not capture the public imagination until the 1890s, with the publication of three books by the American Percival Lowell.

Inspired by the work of the Italian astronomer Giovanni Schiaparelli, who in 1877 had seen a criss‑cross network of straight channels, or canali, on the Martian surface, Lowell built an observatory in Flagstaff, Arizona, from which to examine the planet more closely.

Having mistranslated canali as “canals”, Lowell concluded that the lines were evidence of a vast irrigation system built by an intelligent civilization. By 1910, his theory was complete: Mars was drying out and dying through lack of water, accounting for its red hue and necessitating the irrigations.

The hypothesis eventually foundered on the discovery that Schiaparelli’s canali did not exist: they were optical illusions produced by the telescopes of the period. But the idea that Mars could be wet and inhabited stuck, inspiring hundreds of science fiction novels and films.

In the 1960s and 1970s, a series of Martian flypasts by NASA’s Mariner Spacecraft dispelled any possibility that Mars was at all Earth‑like, showing that carbon dioxide, rather than water and oxygen, was the main component of its atmosphere and ice caps. The Viking landings of 1976went further, finding no conclusive evidence of either water or life, although some investigators still contend that the results of one of the spacecraft’s experiments turned up positive for the existence of micro‑organisms.

The result was a 20‑year hiatus in Mars exploration as space scientists, largely convinced that the planet was barren, turned their attention and dollars elsewhere.

All that changed, however, on August 6, 1996, with the discovery of the Martian meteorite ALH84001, which contained mineral deposits that some scientists interpreted as fossilised microbes.

Interest in Mars was revived overnight.