The deleted tweets added to the secrecy that has surrounded China’s far side landing, a historic first for space exploration, after the space agency didn’t specify a date or time for the landing, or make it possible for people around the world to watch along live. Even scientists at centers that cooperated with the mission were guessing what was happening today.

The secrecy around the landing led some to draw a contrast with NASA, which this week pulled off a fly-by of an object some four billion miles from the Sun, and in November offered a live broadcast of the landing of its Mars InSight rover.

It’s too soon to know what the deleted tweets mean—it’s possible the rover has landed but that China wants to unveil the news in a carefully crafted official announcement before it’s tweeted widely. Twitter is, after all, blocked in the country.

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