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Mars probe set for risky landing Mars probe set for risky landing
(10 minutes later)
An American spacecraft is about to attempt a perilous landing on the surface of Mars.An American spacecraft is about to attempt a perilous landing on the surface of Mars.
Nasa's Phoenix lander is due to touch down on Monday in the far north of the Red Planet, after a 423-million-mile journey from Earth.Nasa's Phoenix lander is due to touch down on Monday in the far north of the Red Planet, after a 423-million-mile journey from Earth.
The probe is equipped with a robotic arm to dig for water ice thought to be buried beneath the surface.The probe is equipped with a robotic arm to dig for water ice thought to be buried beneath the surface.
Scientists say the mission should give the clearest indication yet of whether Mars could once have harboured life.Scientists say the mission should give the clearest indication yet of whether Mars could once have harboured life.
The final seven minutes of the probe's ten-month journey is regarded as the riskiest part of the mission.The final seven minutes of the probe's ten-month journey is regarded as the riskiest part of the mission.
The main goal of the mission is to get below the surface of Mars to where we are almost certain there is water Dr Tom Pike The main goal of the mission is to get below the surface of Mars to where we are almost certain there is water Dr Tom Pike class="" href="/1/hi/sci/tech/7408033.stm">Phoenix Diary: Mission to Mars
After it enters the top of the Martian atmosphere at nearly 5.7km/s (13,000 mph), the probe must perform a series of manoeuvres to come safely to rest.After it enters the top of the Martian atmosphere at nearly 5.7km/s (13,000 mph), the probe must perform a series of manoeuvres to come safely to rest.
It will release a parachute, use pulsed thrusters to slow to a fast walking speed, then come to a halt on three legs.It will release a parachute, use pulsed thrusters to slow to a fast walking speed, then come to a halt on three legs.
If all goes to plan, the Phoenix lander will reach the surface of Mars at 0053 BST (1953 EDT) on 26 May.If all goes to plan, the Phoenix lander will reach the surface of Mars at 0053 BST (1953 EDT) on 26 May.
Nasa controllers will know in about 15 minutes whether the attempt has been successful.Nasa controllers will know in about 15 minutes whether the attempt has been successful.
Phoenix will land further north than previous missionsPhoenix will land further north than previous missions
David Catling from the University of Bristol is a co-investigator on the mission. He said the landing phase would be one of the most exciting and tense parts of the journey, with so much riding on Phoenix's safe descent.David Catling from the University of Bristol is a co-investigator on the mission. He said the landing phase would be one of the most exciting and tense parts of the journey, with so much riding on Phoenix's safe descent.
"Everyone involved is on tenterhooks and eager to start this unique exploration," he said."Everyone involved is on tenterhooks and eager to start this unique exploration," he said.
If all goes to plan, Phoenix will begin a three-month mission to search for ice beneath the Martian surface.If all goes to plan, Phoenix will begin a three-month mission to search for ice beneath the Martian surface.
It will use a robotic arm to dig through the protective topsoil layer and lift samples of both soil and ice to its deck for scientific analysis.It will use a robotic arm to dig through the protective topsoil layer and lift samples of both soil and ice to its deck for scientific analysis.
Building blocksBuilding blocks
Dr Tom Pike of Imperial College, London, is part of the British team involved in the project.Dr Tom Pike of Imperial College, London, is part of the British team involved in the project.
"The main goal of the mission is to get below the surface of Mars to where we are almost certain there is water," he told BBC News."The main goal of the mission is to get below the surface of Mars to where we are almost certain there is water," he told BBC News.
"The orbiters that are around Mars have already surveyed in great detail the area in which we are landing and we know that there is ice - solid water - 10cm, or maybe even less, below the surface."The orbiters that are around Mars have already surveyed in great detail the area in which we are landing and we know that there is ice - solid water - 10cm, or maybe even less, below the surface.
"Water, of course, is of critical importance because it is one of the building blocks - one of the essential habitats we need - for life.""Water, of course, is of critical importance because it is one of the building blocks - one of the essential habitats we need - for life."
Landing on Mars is a notoriously tricky business. Of the 11 missions that have tried to land probes on Mars since 1971 - only five have succeeded.Landing on Mars is a notoriously tricky business. Of the 11 missions that have tried to land probes on Mars since 1971 - only five have succeeded.
Phoenix carries seven science instrumentsPhoenix carries seven science instruments
Phoenix is an apt name for the current mission, as it rose from the ashes of two previous failures.Phoenix is an apt name for the current mission, as it rose from the ashes of two previous failures.
In September 1999, the Mars Climate Orbiter spacecraft crashed into the Red Planet following a navigation error caused when technicians mixed up "English" (imperial) and metric units.In September 1999, the Mars Climate Orbiter spacecraft crashed into the Red Planet following a navigation error caused when technicians mixed up "English" (imperial) and metric units.
A few months later, another Nasa spacecraft, the Mars Polar Lander (MPL), was lost near the planet's South Pole.A few months later, another Nasa spacecraft, the Mars Polar Lander (MPL), was lost near the planet's South Pole.
Phoenix uses hardware from an identical twin of MPL, the Mars Surveyor 2001 Lander, which was cancelled following the two consecutive failures.Phoenix uses hardware from an identical twin of MPL, the Mars Surveyor 2001 Lander, which was cancelled following the two consecutive failures.
The probe was launched on 4 August 2007 on a Delta II rocket from Cape Canaveral Air Force Station in Florida.The probe was launched on 4 August 2007 on a Delta II rocket from Cape Canaveral Air Force Station in Florida.