With just a day to go, NASA's InSight spacecraft is aiming for a bull's-eye touchdown on Mars.
"If you were a Martian coming to explore Earth's interior like we are exploring Mars's interior, it wouldn't matter if you put down in the middle of Kansas or the beaches of Oahu", Bruce Banerdt, from NASA's Jet Propulsion Laboratory, said in a statement.
In space, the Mars Reconnaissance Orbiter (MRO) will be tracking InSight's progress down to the surface, however, it is not created to relay those message real-time.
An artist illustration of the InSight lander on Mars. Tricky from the lander's deck. It just takes that smidgen of luck, as well, that the lander experiences nothing unexpected, on the way down. Investigators have their fingers crossed that the device will also detect liquid water sloshing around beneath the surface as well active volcanoes underground.
In recent days, NASA has been commanding the spacecraft to make minor course corrections to ensure InSight enters the Martian atmosphere at the proper angle to within about a quarter of a degree.
To make accurate measurements, those instrumentsshouldn't be disturbed.
The probe will burrow considerably deeper than the 2 metres planned for ESA's ExoMars rover (although the latter is a tad more mobile) and far more than previous NASA landers, which have mainly scratched at the surface.
Earth's overall success rate at Mars is 40 per cent.
Mission scientists can use these to track the lander's position with extreme precision, and so deduce how much Mars wobbles on its axis as it orbits the sun.
The sharpest view of Mars ever taken from Earth Nasa Getty Images
Curiosity, Opportunity and Spirit have already provided scientists with a wealth of data on Mars from samples collected on the planet's surface, revealing the composition of its minerals and showing that the planet might have been capable of supporting life in the distant past.
The instrument, mounted on the deck of the lander, will also give an indication if the core is liquid or solid.
If all goes according to plan, the lander will drop softly onto the red dirt of a flat, boring equatorial plain called Elysium Planitia at about 5 miles per hour (8 km/h) - slightly faster than walking speed.
"It'll be sending back data in real time", Grover says, "and the MarCO spacecraft will be helping with that - relaying the data".
Of 43 other worldwide attempts to send orbiters, probes, landers or rovers to Mars, 25 have not made it. Seismic activity on Mars is thought to come from cracks forming in the crust, with the planet's interior energy thought to be less intense than Earth's. The spacecraft will then send out two signals-one to say it has landed then another to confirm it was a successful touchdown.
Only about 40 percent of the landers and rovers sent to the red planet during the last five decades have ever made it safely down to the surface, and of the global space agencies that have tried, only NASA has succeeded in making a soft landing on Mars.
When it lands six-and-half minutes later, it will be travelling a mere 8kmh.
After that, the spacecraft turns, so its heat shield is pointing in the right direction. Its 77-mile descent to the surface will be slowed by atmospheric friction, a giant parachute and retro rockets.
Here's a minute-by-minute look at the biggest moments of InSight's landing sequence - any of which could doom the robot. At this point, the probe is still traveling faster than the speed of sound, so InSight has a special parachute designed for supersonic speeds. No lander has dug deeper than several inches, and no seismometer has ever worked on Mars. France and Germany have contributed about $180m for SEIS and HP³ respectively.
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