What altitude did a Canberra reach on a rocket motor in 1957?

On 28 August 1957, the Canberra B.2 WK163, fitted with a Napier Double Scorpion rocket motor, achieved an altitude record of 70,310 ft (21,430 m).

On 4 May 1953, the Canberra B.2 WD952, fitted with Rolls-Royce Olympus engines, set a world altitude record flying at 63,668 ft (19,406 m). On 29 August 1955 another altitude record was set, of 65,889 ft (20,083 m). The Canberra was designed without defensive armament, which had historically proven unable to match fighters, and the resulting performance gain let it avoid air-to-air combat entirely.

The RB-57F received a wing with a span of more than 122 ft (37 m), 16 ft (4.9 m) greater than that of the RB-57D. It also carried two removable Pratt & Whitney J60-P-9 turbojets, mounted in pods fitted to the wings outboard of the main engines. The initial batch of 12 aircraft under the First Chip programme was converted from B-57B airframes from the 1952 and 1953 production runs. The next four conversions came from RB-57D airframes taken out of storage. The last three were built from RB-57A airframes.