New Zealand astronomers are among thousands worldwide who are counting down the hours until Nasa's Curiosity probe lands on Mars on Monday.
But before they get too excited about what results may come from the operation, the machine first has to land on the planet, a feat which is incredibly complicated and involves high speeds, soaring temperatures, a parachute and rockets.
In New Zealand, we'll find out if the landing was successful about 5.30pm on Monday.
A group of about 50 people will gather in Christchurch to watch the landing live from Nasa's channel, while astronomer Alan Gilmore will be keeping a close eye on developments from Mt John Observatory, near Lake Tekapo.
About four billion years ago Mars had a similar warm and wet climate as Earth, Gilmore said. It had oceans, but the water had since dried up.
If signs of life were found during the mission, then they would probably date back to three or four billions years ago, Gilmore said.
However, it wasn't impossible that some bacteria may have adapted to the environment and may still exist.
Some areas produce methane gas during Mar's summer, which "could be evidence for microbes hiding under the surface and producing methane, or it could be completely natural," Gilmore said.
"If we could find bacteria of some sort on another planet there would be extreme interest because it might give us some clues to how life actually forms."
Curiosity will canvass Mar's Gale Crater, which was formed 3.5 to 3.8 billion years ago when it was hit by a meteor. It has been targeted because it has many signs that it once held water, a key ingredient for life.
"Gale is special because we can see both clays and sulfate minerals, which formed in water under different conditions," a description on Nasa's website says.
"They also may preserve signs of past life - if it existed, that is! The history of water at Gale, as recorded in its rocks, will give Curiosity lots of clues to study as it pieces together whether Mars ever could have been a habitat for small life forms."
Unlike earlier rover missions to Mars, Curiosity is much larger and carries more equipment, which can gather samples of rocks and soil, process them and distribute them to onboard test chambers.
It will never return to Earth, but will send information back.
There was no clear evidence that there is or was life on Mars, so hopefully this mission will either prove or disprove the theory, Gilmore said.
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