|
Mercury Information
Mercury
Home
Mercury
Goals
Mercury
Overview
Mercury
Spacecraft
Mercury
Flight Summary
Mercury
Unmanned Missions
Mercury
Manned Missions
JSC
Mercury Image Directory
Results
of the First United States Manned Orbital Spaceflight
February 20, 1962
|
Friendship 7 MA-6 (23)
Friendship 7
Pad LC-14
Atlas (6)
Crew:
John H. Glenn, Jr.
Milestones:
8/27/61 - Capsule arrived at Cape Canaveral
2/15/62 - Flight Safety Review
2/20/62 - Launch
Payload: Spacecraft No. 13, Vehicle Number 109-D
Mission Objective:
Place a man into earth orbit, observe his reactions to the space environment and safely return
him to earth to a point where he could be readily found. The Mercury flight plan during the first orbit was to maintain optimum spacecraft attitude for
radar tracking and communication checks.
Orbit:
Altitude: 162.2 x 100 statute miles
Inclination: 32.54
Orbits: 3
Period: 88min 29sec
Duration: 0 Days, 4 hours, 55 min, 23 seconds
Distance: 75,679 statute miles
Velocity: 17,544 mph
Max Q: 982 psf
Max G: 7.7
Launch:
February 20, 1962. 9:47:39 am EST. Cape Canaveral Launch Complex 14. Powered flight
lasted 5 minutes 1 second and was completed normally.
The mercury countdown began on 1/27/62 and was performed in two parts. Precount
checks out the primary spacecraft systems, followed by a 17.5 hour hold for pyrotechnic
checks, electrical connections and peroxide system servicing. Then the countdown began. The launch countdown proceeded to the T-13 minute mark and then was canceled due to
adverse weather conditions. After cancellation, the mission team decided to replace the
carbon dioxide absorber unit and the peroxide system had to be drained and flushed to prevent corrosion. Launch vehicle systems were then revalidated and a leak was discovered
in the inner bulkhead of the fuel tank that required 4-6 days to repair. The launch was rescheduled to 2/13/62 and then to 2/14/62 to all the bulkhead work to complete. The
precount picked up again on 2/13/62, 2/15/62 and 2/16/62 but was canceled each time due
to adverse weather. The launch was then rescheduled for 2/20/62.
|
During the launch countdown on 2/20/62, all systems were energized and final overall
checks were made. the count started at T-390 minutes by installing and connecting the
escape-rocket igniter. The service structure was then cleared and the spacecraft was
powered to verify no inadvertent pyrotechnic ignition. The personnel then returned to the
service structure to prepare for static firing of the reaction control system at T-250 minutes. The spacecraft was then prepared for boarding at T-120 minutes. The hatch was put into
place at T-90 minutes. During installation a bolt was broken, and the hatch had to be
removed to replace the bolt causing a 40 minute hold. From T-90 to T-55 final mechanical
work and spacecraft checks were made and the service was evacuated and moved away
from the launch vehicle. At T-45 minutes, a 15 minute hold was required to add fuel to the
launch vehicle and at T-22 minutes and additional 25 minutes was required for filling the
liquid-oxygen tanks as a result of a minor malfunction in the ground support equipment used to pump liquid oxygen into the launch vehicle. At approximately T-35 minutes, filling of the liquid-oxygen tanks began and final spacecraft and launch vehicle systems checks were
started.
At T-10 minutes the spacecraft went on internal power. At T-6min 30
seconds, a 2 minute hold was required to make a quick check of the network computer at Bermuda. The launch vehicle went on internal power at T-3 minutes. At T-35 seconds the spacecraft umbilical was ejected and at T-0 the main engines started. Liftoff
occurred at T+4 seconds at 9:47:39am EST.
Landing:
February 20, 1962. 14:43:02 am EST. 800 miles southeast of Bermuda.
Recovered by the destroyer USS Noa. Lookouts on the destroyer sighted the main parachute at an altitude of 5,000 ft from a range of 5nm. The Noa had the spacecraft aboard
21 minutes after landing and astronaut John Glenn remained in the spacecraft during pickup.
Original plans had called for egress through the top hatch but Glenn was becoming
uncomfortably warm and it was decided to exit by the easier egress path.
Mission Highlights:
Mission Successful. First American in orbit. Total time weightless 4 hours 48min 27sec.
During the flight only two major problems were encountered: (1) a yaw attitude control jet
apparently clogged at the end of the first orbit, forcing the astronaut to abandon the
automatic control system for the manual-electrical fly-by-wire system; and (2) a faulty switch
in the heat shield circuit indicated that the clamp holding the shield had been prematurely
released- a signal later found to be false. During reentry, however, the retropack was not jettisoned but retained as a safety measure to hold the heat shield in place in the event it had
loosened.
(Reference NASA SP-4001 - Project Mercury: A Chronology)
(Reference NASA - Results of the First US Manned Orbital Space Flight)
(Reference NASA SP-4201 - This New Ocean)
|
