The American space agency is set to launch its latest mission to Mars.
InSight will be the first probe to focus its investigations predominantly on the interior of the Red Planet. The static lander will put seismometers on the surface - including sensors from the UK - to feel for "Marsquakes".
These tremors should reveal how the underground rock is layered - data that can be compared with Earth to shed further light on the formation of the planets 4.6 billion years ago.
"As seismic waves travel through [Mars] they pick up information along the way; as they travel through different rocks," explained Dr Bruce Banerdt, InSight's principal investigator. "And all those wiggles you see on seismograms - scientists understand how to pull that information out. After we've gotten many, many Marsquakes from different directions, we can put together a three dimensional view of the inside of Mars."
Lift-off on an Atlas rocket from the Vandenberg Air Force Base in California is scheduled for 04:05 local time (12:05 BST) on Saturday, although forecast fog may force a delay.
- Mars mission: Ready to rumble
- Agencies aim to bring back Mars rocks
- Europe's Mars rover takes shape
- Nasa last sent seismometers to the Red Planet on the Viking landers
in the 1970s. But these missions failed to detect ground vibrations
because the instruments were positioned on the body of the probes.
All they recorded was the landers' shaking as the wind whistled by. InSight, by contrast, is going to place its seismometers directly in the Martian dirt.
How many quakes will be detected over the course of a year is uncertain, but estimates suggest perhaps a couple of dozen. They are likely to be small - probably well less than a Magnitude 3, which many people on Earth would sleep through.
However, even these gentler signals will carry sufficient information about the subsurface to allow scientists to construct a model of Mars' depths and composition.
The planet should have a metal core, a dense mantle and a lighter crust - but where precisely the boundaries lie is speculative.
The seismometer experiment is French-led. The European nation has provided the broadband sensors that will detect low-frequency vibrations of the ground, while the UK has contributed a trio of microseismometers, about the size of a pound coin, that will go after the higher frequencies.
A good source of these short period vibrations is likely to be meteorite impacts.
