NASA's spacecraft is about to touch down on Mars – and it's been so long since the last Martian landfall that Mars mania is gripping everybody. But what exactly is NASA doing on the 'red planet' now?
NASA's first robotic lander designed to study the deep interior of Mars is on course for a planned touchdown on the 'red planet' after a six-month voyage through space on Monday.
Travelling 548 million km from Earth, the Mars InSight spacecraft is set to reach its destination on the dusty, rock-strewn surface at about 2000 GMT.
Around 60 percent of 43 attempts to reach Mars with rovers, orbiters and probes by space agencies from around the world have failed since 1960.
'Six and a half minutes of terror'
The high drama of the entry, descent and landing phase, coined "six and a half minutes of terror," begins at 1940 GMT at NASA's Jet Propulsion Laboratory in Pasadena, California, home to mission control for Mars Insight.
The mission control team at NASA's Jet Propulsion Laboratory (JPL) near Los Angeles prepared to conduct a final adjustment to the InSight's flight path on Sunday to manoeuvre the spacecraft closer toward its entry point over Mars.
If all goes according to plan, InSight will streak into the pink Martian sky nearly 24 hours later at 19,800 kph. Its 123 km descent to the surface will be slowed by atmospheric friction, a giant parachute and retro rockets.
But then, the spacecraft's thrusters begin to fire, further slowing down the 365-kilogram (800-pound) spacecraft to a speed of just about 8 kph when it reaches the surface.
When it lands six and a half minutes later, it will be travelling a mere 8 kph.
Goal of the mission
InSight will spend 24 months – about one Martian year – using seismic monitoring and underground temperature readings to unlock mysteries about how Mars formed, and by extension, the origins of the Earth and other rocky planets of the inner solar system.
Concentrating on planetary building blocks, InSight has no life-detecting capability, nor is it a rock-collecting expedition.
Instead, the stationary 360-kilogram lander will use its 1.8-metre robotic arm to place a mechanical mole and seismometer on the ground.
The self-hammering mole will burrow 5 metres down to measure the planet's internal heat, while the ultra-high-tech seismometer listens for possible marsquakes. Nothing like this has been attempted before at our smaller next-door neighbour, nearly 160 million km away.
No experiments have ever been moved robotically from the spacecraft to the actual Martian surface.
No lander has dug deeper than several inches, and no seismometer has ever worked on Mars.
By examining the deepest, darkest interior of Mars – still preserved from its earliest days – scientists hope to create 3D images that could reveal how our solar system's rocky planets formed 4.5 billion years ago and why they turned out so different.
One of the big questions is what made Earth so hospitable to life.
Mars once had flowing rivers and lakes; the deltas and lakebeds are now dry, and the planet cold. Venus is a furnace because of its thick, heat-trapping atmosphere.
By listening for tremors on Mars, whether from quakes or meteor impacts or even volcanic activity, scientists can learn more about its interior and reveal how the planet formed.
The goal is to map the inside of Mars in three dimensions, "so we understand the inside of Mars as well as we have come to understand the outside of Mars," Banerdt told reporters.
The operations of the InSight are based on a carefully orchestrated sequence – already fully pre-programmed onboard the spacecraft.
Since there is no joystick back on Earth for this spacecraft, and no way to intervene if anything goes wrong.
Confirmation of touchdown could take minutes – or hours. At the minimum, there's an eight-minute communication lag between Mars and Earth.
A pair of briefcase-size satellites trailing InSight since liftoff in May will try to relay its radio signals to Earth, with a potential lag time of under nine minutes.
The InSight spacecraft was built near Denver, Colorado by Lockheed Martin.
France's Centre National d'Études Spatiales (CNES) made the Seismic Experiment for Interior Structure (SEIS) instrument, the key element for sensing quakes.
The German Aerospace Center (DLR) provided a self-hammering mole that can burrow 16 feet (five metres) into the surface – further than any instrument before – to measure heat flow.
Spain's Centro de Astrobiologia made the spacecraft's wind sensors.
Other significant contributions to the project came from the Space Research Center of the Polish Academy of Sciences and Astronika in Poland, the Swiss Institute of Technology in Switzerland, and the Imperial College and Oxford University in Britain.
Because it's been so long since NASA's last Martian landfall – the Curiosity rover in 2012 – Mars mania is gripping not only space and science communities, but everyday folks.
Viewing parties are planned coast to coast at museums, planetariums and libraries, as well as in France, where InSight's seismometer was designed and built.
The giant NASDAQ screen in New York's Times Square will start broadcasting NASA Television an hour before InSight's scheduled 2000 GMT touchdown; so will the National Air and Space Museum's Udvar-Hazy Center in Chantilly, Virginia, and the Denver Museum of Nature and Science.
But the real action, at least on Earth, will unfold at NASA's Jet Propulsion Laboratory in Pasadena, California, home to InSight's flight control team. NASA is providing a special 360-degree online broadcast from inside the control center.