When astronaut John Grunsfeld was preparing to fly to the Hubble Space Telescope for its last ever servicing mission in 2009, he got in touch with astronomer Neta Bahcall.

Bahcall and her husband, John Bahcall, had been involved in the Hubble project since well before its launch. On multiple occasions, John Bahcall had saved the telescope from being canned by Congress. He was instrumental in setting up its final servicing mission, but had passed away in 2005, well before it took place.

Grunsfeld told Neta that he had been so inspired by John that he would like to take a token with him when he went to visit Hubble for the final time. She agreed, and sent their wedding rings for a tour around Earth.

ESA

Excerpted from the NaturePodcast. For more Hubble highlights, see Nature's coverage of Hubble's 25th anniversary.