The Hubble Space Telescope’s (HST) Servicing Mission 4 (SM4), flown by the Shuttle Atlantis in May 2009, was the last scheduled shuttle mission for HST (launched 11th of May 2009, STS-125). SM4 installed the replacement data-handling unit, repaired the ACS and STIS systems, installed improved nickel hydrogen batteries, and replaced other components including all…