The Hubble Space Telescope's Advanced Camera for Surveys (ACS) went into "safe mode" January 27. The space-based telescope's instrument has operated on backup electronics since June 30, 2006, and now doesn't work. The problem calls into question whether NASA's upcoming servicing mission 4, planned for September 2008, will be a "go." Not going ahead with the servicing mission would a disappointment, considering the bounty of awe-inspiring images Hubble has already given us.