She was struck from the Naval Vessel Register on 22 June 1955. The Navy reactivated the ship, taking custody on 6 July 1956, for service with MSTS to be operated, under charter, by Marine Transport Lines, Incorporated. On 13 March 1958 the Maritime Administration took permanent custody of the ship for lay up in the Maritime Reserve Fleet at Orange. She was struck from the Naval Vessel Register on the same date. On 19 October 1964 the Maritime Commission returned permanent custody of "Mission De Pala" to the Navy for conversion into a missile‑range instrumentation ship. Converted at General Dynamics Quincy Shipbuilding Division, Quincy, Massachusetts she was "jumboized" by having a 72‑foot section added amidships, an extensive array of electronic equipment was installed and a nest of antennas added topside. Essentially the ship was virtually rebuilt in order to prepare her for her new role. While under conversion, she was renamed and redesignated "Johnstown" (AGM-20) on 8 April 1965, but she was renamed "Redstone" on 1 September 1965. Upon completion of conversion, she was accepted on 30 June 1966 by MSTS, for service as USNS "Redstone" (T-AGM-20). Designed for use as a seagoing tracking and communications station for the Apollo program test series and moon shot, into 1969, she continued these duties and played her part in helping fulfill the late President John F. Kennedy's pledge to land a man on the moon before 1970. The ship was removed from service on 6 August 1993. She was struck from the Naval Register on 7 December 1993. On 6 August 1993 the ship was placed in the James River reserve fleet until withdrawn briefly 23 June through 31 August 1994 for stripping before sale and scrapping. After being sold for scrapping the ship finally left the fleet on 30 January 1995.