Neil deGrasse Tyson @neiltyson
FYI: Every 26 months a launch window opens between Earth & Mars, enabling a probe to arrive using minimal fuel, allowing heavier payloads. So anybody going to Mars will leave & arrive at about the same time. In the current window, the UAE, China, & USA all sent probes to Mars. https://t.co/cWQNPNu9HX — PolitiTweet.org