Space probes carrying robotic explorers near Mars

CAPE CANAVERAL, FLA. — After hurtling hundreds of millions of kilometres through space since last summer, three robotic explorers are ready to hit the brakes at Mars. The stakes — and anxiety — are sky high.

The United Arab Emirates’ orbiter reaches Mars on Tuesday, followed less than 24 hours later by China’s orbiter-rover combo. NASA’s rover, the cosmic caboose, will arrive on the scene a week later, on Feb. 18, to collect rocks for return to Earth.

Both the UAE and China are newcomers at Mars, where more than half of Earth’s emissaries have failed. China’s first Mars mission, a joint effort with Russia in 2011, never made it past Earth’s orbit.

All three spacecraft rocketed away within days of one another last July, during an Earth-to-Mars launch window that occurs only every two years. That’s why their arrivals are also close together.

Called Amal, or “Hope” in Arabic, the Gulf nation’s spacecraft is seeking an especially high orbit — 22,000 km by 44,000 km high — all the better to monitor the Martian weather.

China’s duo — called Tianwen-1, or “Quest for Heavenly Truth” — will remain paired in orbit until May, when the rover separates to descend to the dusty, ruddy surface. If all goes well, it will be only the second country to land successfully on the red planet.

The U.S. rover Perseverance, by contrast, will dive in straight away for a sky-crane touchdown similar to the Curiosity rover’s grand Martian entrance in 2012.