Nasa's Mars landing has been hailed as an "extraordinary technological achievement" and something akin to "magic" by Northern Ireland experts.
Its science rover Perseverance, the most advanced astrobiology laboratory ever sent to another planet, streaked through the Martian atmosphere on Thursday and landed safely on the floor of a vast crater.
Its mission is to search for signs of ancient life, and explore and collect samples for future return to Earth from diverse environments on Mars.
Perseverance has since sent back images, which has prompted the space agency to describe it as an "amazing accomplishment".
Professor Michael Burton, director of Armagh Observatory and Planetarium, told the Belfast Telegraph: "Watching the landing, live on NASA TV, of a spacecraft on another planet was an absolutely amazing experience.
"You could feel the tension in the NASA control room, hear the little exclamations from the mission team, as the spacecraft went through an extraordinary sequence of steps to come to a safe landing on Mars, just seven minutes after hitting the top of its atmosphere while moving at a speed of five kilometres every second."
Professor Burton continued: "This was an extraordinary technological achievement. Now, having landed near the delta of an ancient river and lake on Mars, begins the most exciting stage, of searching for evidence of past life that might have once existed on Mars."
Dr Apostolos Christou, a research astronomer at Armagh Observatory and Planetarium, said it was an extremely complex landing operation.
"Although NASA has been responsible for a number of successful landings since 1976, one cannot overemphasise the risk of the undertaking," he explained.
"About half of all landing attempts so far have failed. To succeed, a sequence of actions have to take place, if even one does not or does so too early or too late, your multi-billion dollar spacecraft becomes a useless pile of junk on Mars.
"Making it happen seems to some of us like magic, but in reality it's just what you get with hard work and testing the hardware and the software as if it were on Mars."
After the rover, which blasted off from Earth last July, entered the Martian atmosphere there were "seven minutes of terror" as it made its way to the surface.
It took more than 11 minutes for news of the safe landing to reach Earth, arriving at just before 9pm (GMT) on Thursday.
Steve Jurczyk, Nasa's acting administrator, said: "It's amazing to have Perseverance join Curiosity on Mars and what a credit to the team.
"Just what an amazing team to work through all the adversity and all the challenges that go with landing a rover on Mars, plus the challenges of Covid. And just an amazing accomplishment."
Perseverance's Twitter account also marked its arrival on the red planet, tweeting that it had landed safely, and posting pictures from the rover of its "forever home".
The arrival of this image, and second taken from behind the rover, showing a flat, rocky surface, was met with a second round of cheers as mission control celebrated the achievement.
More images, videos and sounds from the landing are expected to start arriving from the rover over the weekend.
But early indications suggest Perseverance had landed on a relatively flat surface, and not too far from some sand dunes which will have to be navigated in order to reach the delta.
Perseverance will spend the coming years scouring for signs of ancient microbial life in a mission that will bring back samples from Mars to Earth and prepare the way for future human visitors.
The research destination of the rover - a scientific laboratory the size of a car - is Jezero crater, a 28-mile-wide depression containing sediments of an ancient river delta.
Scientists know that 3.5 billion years ago, Jezero was the site of a large lake, complete with its own delta. They believe that while the water may be long gone, somewhere within the crater, or maybe along its 2,000-foot-tall (610 metre) rim, evidence that life once existed there could be waiting.
Perseverance will gather rock and soil samples using its drill, and will store the sample cores in tubes on the Martian surface ready for a return mission to bring around 30 samples to Earth in the early 2030s.
Researchers from the UK will study the samples that are returned from Mars. Selected samples will be collected by drilling down to several centimetres and then sealed in sample tubes and stored on the rover.
When the rover reaches a suitable location, a cache of tubes will be dropped on the surface of Mars to be collected by the Sample Fetch Rover, being developed by Airbus in Stevenage, which will take them to the Nasa Mars Ascent vehicle.
Perseverance also carries the Ingenuity Mars Helicopter, which will fly short distances from the rover in the first attempt at powered, controlled flight on another planet.
A successful flight test could lead to more flying probes on other planets, as well as help astronauts make future expeditions to Mars.