Happy launch birthday to our X-ray hunter @ESA_XMM! 🚀 In space since 1999 to study the hot and violent Universe: black holes, exploding stars, gamma-ray bursts and more #OTD https://t.co/3q1eDrs1a3 pic.twitter.com/HMrFfmm5zo

— ESA Science (@esascience) December 10, 2017