According to mission rules, this ought to be quite enough hydrogen peroxide, reckoned Kraft, to thrust the capsule into the retrofire attitude, hold it, and then to reenter the atmosphere using either the automatic or the manual control system ."
32.
The Mercury spacecraft did not have an on-board computer, instead relying on all computation for re-entry to be calculated by computers on the ground, with their results ( retrofire times and firing attitude ) then transmitted to the spacecraft by radio while in flight.
33.
Each craft was planned to slow to about 110 m / s ( 4 % of speed before retrofire ) by a main solid fuel retrorocket, which fired for 40 seconds starting at an altitude of 75.3 km above the Moon, and then was jettisoned along with radar unit at 11 km from the surface.
34.
After orbiting the Earth 14 times, the command for retrofire was sent by the " Yuanwang 3 " tracking ship off the coast of Namibia at 18 : 49 UTC . After a successful reentry it landed about 415 km east of its launch pad and 110 km north-west of Wuhai, Inner Mongolia.
35.
The resulting Voskhod was a stripped-down vehicle from which any excess weight had been removed; although a backup retrofire engine was added, since the more powerful Voskhod rocket used to launch the craft would send it to a higher orbit than the Vostok, eliminating the possibility of a natural decay of the orbit and reentry in case of primary retrorocket failure.
36.
At the retrofire event, the pitch horizon scanner malfunctioned once more, forcing Carpenter to manually control his reentry, which caused him to overshoot the planned splashdown point by . ( " The malfunction of the pitch horizon scanner circuit [ a component of the automatic control system ] dictated that the pilot manually control the spacecraft attitudes during this event . " ) The PHS malfunction jerked the spacecraft off in yaw by 25 degrees to the right, accounting for of the overshoot; the delay caused by the automatic sequencer required Carpenter to fire the retrorockets manually.
