Free Astronomy Magazine March-April 2021

but then requires that missions be absolutely ready when the window opens for launch – else risking a mis- sion delay of 26 months, the time between these ideal Earth-Mars launch windows. The first arrival this month was the United Arab Emirates’ “Hope” or- biter, which launched on July 19, 2020 and entered orbit on February 9, 2021. With a mission to study the Martian atmosphere and climate, the UAE has established itself as a nation with the technical know- how to be among the few “first- firsts,” having their first Mars mis- sion work successfully the first time. The second mission is China’s Tian- wen-1, launched on July 23, 2020 and in orbit as of February 10, 2021, with a planned lander descent to the Martian surface set for May of 45 MARCH-APRIL 2021 MARS ROVERS S cientific equipment on Persever- ance, with international collabo- rations labeled. [NASA/JPL]