The image was marred by specks of debris. But the quick look at the surroundings showed a flat surface with few if any rocks — just what scientists were hoping for.
Much better pictures will arrive in the hours and days ahead.
"What a relief," said JPL's chief engineer, Rob Manning. "This is really fantastic."
He added: "Wow! This never gets old."
Manning said the landing appeared to be flawless.
"This is what we really hoped and imagined in our mind's eye," he said.
"Sometimes things work out in your favour."
The three-legged InSight spacecraft reached the surface after going from 19,800 km/h to zero in six minutes flat as it pierced the Martian atmosphere, using a parachute and braking engines to slow down.
Radio signals confirming the landing took more than eight minutes to cross the nearly 160 million km between Mars and Earth.
It was Nasa's ninth attempt to land at Mars since the 1976 Viking probes. All but one of the previous US touchdowns were successful.
Nasa last landed on Mars in 2012 with the Curiosity rover.
Viewings were held coast to coast in the US at museums, planetariums and libraries, as well as New York's Times Square.
"Landing on Mars is one of the hardest single jobs that people have to do in planetary exploration," InSight's lead scientist, Bruce Banerdt, said before the landing.
"It's such a difficult thing, it's such a dangerous thing that there's always a fairly uncomfortably large chance that something could go wrong."
-AP
