Feb. 10 (UPI) -- A Chinese Mars spacecraft, Tianwen-1, successfully reached orbit at the Red Planet on Wednesday morning, as the second of three nations' Mars missions that launched in July.
The Tianwen-1 spacecraft fired its thrusters for orbital insertion a little after 7 a.m. EST, according to Chinese state media, but few details were announced.
Tianwen-1 is an orbiter that will study the Martian atmosphere, and it carries a rover that China plans to send to the planet's surface in May.
China's arrival at Mars follows a successful United Arab Emirates mission, the Hope probe, which arrived there Tuesday morning and also achieved a successful orbit.
NASA's Mars rover, Perseverance, is planned to arrive at Mars on Feb. 18.
Aerospace scientists and Mars experts around the world are watching the Chinese mission for new information about the planet, said Jeremy Riousset, assistant professor of planetary sciences and aerospace at Florida Institute of Technology in Melbourne, Fla.
"All three missions are of great interest," Riousset said. "For the Chinese mission, they remain quite secretive, so it's a little more difficult to assess their chances of success."
Achieving a good orbit around Mars is extremely difficult, Riousset said, but landing a rover on Mars will be even more difficult. Part of the challenge is that everything must happen robotically because of an 11-minute delay in communications with Mars.
Achieving a good orbit at Mars is "never something that's going to be low-risk or easy" said Zachary Putnam, assistant professor of aerospace at the University of Illinois at Urbana-Champaign.
That's partly because of the long distance involved between Earth and Mars, and the delay to relay corrections in case anything goes wrong.
But Putnam said technology for achieving good orbit has evolved, and China may take advantage of such innovations.
"The basic idea is, such a spacecraft uses sensors and star charts to know where it is, and it pretty accurately knows how fast it's going," Putnam said. "So as it approaches Mars, it should know where we'd like it to be and what speed it should reach to make a good orbit."
The Chinese probe conducted an orbital correction Friday evening, according to the China National Space Administration. That correction placed it in the right position to enter the Red Planet's gravity well.
The administration also published a black-and-white picture of Mars taken by Tianwen 1 when the probe was about 1.3 million miles from the planet.
The Chinese probe was launched on a Long March 5 rocket July 23 from the Wenchang Space Launch Center in Hainan province.