Now’s the last chance to send your name to one of Jupiter’s moons on NASA’s Europa Clipper

NASA’s campaign to gather names for a sort of “message in a bottle” that will fly with its upcoming Europa Clipper mission closes after this weekend, so if you were hoping to participate but haven’t yet made your submission, you’d better hurry up and do so. The signatures will accompany a poem written for Europa by US Poet Laureate Ada Limón, which will be engraved in Limón’s handwriting on a metal plate attached to the spacecraft. Europa, one of Jupiter’s largest moons, is thought to have a deep saltwater ocean beneath its icy crust — and there, the conditions could be suitable for microbial life.

To enter the Message in a Bottle campaign, you just need to go to and fill out a short signup form. The deadline is tomorrow, December 31. So far, more than 2.4 million people have added their names. According to NASA, the names of everyone who participated will be stenciled in tiny, tiny letters onto microchips using an electron beam that can create lines of text smaller than 1/1000th the width of a human hair. These microchips will be affixed to the plate containing the poem.

The Europa Clipper spacecraft is scheduled to launch in October 2024, and it’ll be another six years from then before it reaches Jupiter’s orbit. Once there, it’ll investigate Europa’s potential habitability through a series of close flybys. Europa is one of an estimated 95 moons circling Jupiter and among the longest known to humanity.