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Mercury-Redstone 3

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Mercury-Redstone 3
Crew
Members1
End of mission

Mercury-Redstone 3 was a U.S. Mercury program manned space mission launched on May 5, 1961 using a Redstone rocket, from Launch Complex 5 (LC-5) at Cape Canaveral, Florida. The Mercury spacecraft was named Freedom 7 which performed a suborbital flight piloted by astronaut Alan Shepard, who became the first American in space. The flight lasted less than 16 minutes and attained an altitude of just over 187 kilometres (116 mi).

Unlike the earlier Soviet Vostok 1 flight, Shepard did not orbit the Earth, but simply went up and down in a ballistic trajectory which required a less-powerful rocket and simpler guidance. He did, however, become the first astronaut to safely return to Earth inside his vehicle. In the Vostok 1 mission, pilot Yuri Gagarin parachuted from his vehicle prior to landing.

Crew

Position Astronaut
Pilot Alan B. Shepard, Jr.
First spaceflight

Backup crew

Position Astronaut
Pilot John H. Glenn, Jr

Mission parameters

  • Mass: 1,295 kg (2,855 lb) (apogee)
  • Maximum Altitude: 187.42 km (116.46 mi)
  • Range: 487.26 km (302.77 mi)
  • Launch Vehicle: Redstone rocket

Mission highlights

The Freedom 7 spacecraft was delivered to Cape Canaveral on December 9, 1960.[1] Freedom 7 was spacecraft #7 and was given special attention at the factory since it was selected for the first manned suborbital flight in October 1960. It was originally expected to be ready for launch almost immediately. However, 21 weeks of unplanned preparation would be needed before it could be launched on its mission. Reaction control system rework was responsible for postponement of the launch until at least March 6, 1961. Damaged and corroded peroxide lines that needed replacement forced a further delay of eight days. The simulated mission test needed to be rerun and structural and equipment defects corrected. The MR-3 mission was finally ready to be launched on May 2, 1961.

Three astronauts were chosen as finalists to fly the MR-3 mission in January, 1961 and on February 22, 1961 their names were announced to the public. The three were Alan Shepard, Gus Grissom and John Glenn. The public was not told who would actually fly the mission until after a May 2, 1961 launch attempt was canceled due to weather.[2] It was then revealed that Shepard was suited up and waited for three hours in Hangar "S" at Cape Canaveral for the launch. The May 2 launch was canceled two hours and 20 minutes before launch due to weather conditions.

In the early morning of May 5, 1961, Shepard donned his pressure suit with the assistance of technician Joe W. Schmitt. A transfer van carried him to the launch pad and he ascended the gantry at 10:15 UTC. At 10:21 UTC he entered Freedom 7 and the gantry crew helped attach the harness and hose connections. He would spend the next four hours in the spacecraft waiting for the launch.

At 9:34 AM EST (14:34 UTC),[3] there were 45 million Americans watching and listening live to their televisions when at about two seconds after liftoff Alan Shepard reported, "Ahh, Roger; lift-off and the clock is started... Yes, sir, reading you loud and clear. This is Freedom 7. The fuel is go; 1.2 g [12 m/s²]; cabin at 14 pounds per square inch (97 kPa); oxygen is go... Freedom 7 is still go!" He was riding on Redstone MRLV-7 and in Mercury spacecraft #7. In all subsequent Mercury flights, the number 7 was appended to the astronaut-chosen spacecraft/mission name and call sign in honor of the fact that there were seven original Mercury astronauts. At T+16 seconds (where T is the time of launch) the pitch program started and the Redstone began a 2 deg/s pitch over, from 90 to 45 degrees. At about T+40 seconds, the pitch program was complete. Max-Q was reached at one minute 24 seconds into the flight when Freedom 7 experienced a maximum dynamic pressure of 2.9 kilopascals (0.42 psi). During ascent the cabin pressure sealed off at 38 kilopascals (5.5 psi) of pure oxygen. At two minutes into the flight, Shepard experienced 6 g (59 m/s²) of acceleration.

Launch of the Mercury-Redstone 3 spacecraft on May 5, 1961, 9:34 a.m. EST, with Alan Shepard on board.

The Redstone's engine shut down on schedule at two minutes, 21.8 seconds. Outside the spacecraft, its shingle temperature reached 220 °F (104 °C). The cabin temperature was 91 °F (33 °C). The temperature inside Shepard's pressure suit was 75 °F (24 °C). Escape tower separation occurred two minutes, 22.2 seconds after launch. This is one second earlier than nominal and there was some indication from the recovered escape tower that the jettison rockets had been fired manually. Shepard said he did not remember pulling the manual "JETT TOWER" override ring.

Three posigrade rockets with 400 pounds-force (1,800 N) thrust each fired for one second and separated the spacecraft from the Redstone booster at a rate of 15 feet per second (4.6 m/s) at two minutes, 32.3 seconds after launch. At three minutes the automatic attitude control system (AACS) rotated the spacecraft 180 degrees to a heatshield-forward position. The spacecraft remained in this position for the remainder of the flight. The spacecraft had almost reached apogee in its ballistic flight.

Shepard took manual control of the spacecraft attitude one axis at a time from the automatic attitude control system. The first thing he did was position the spacecraft to its retrofire attitude of 34 degrees pitch (nose of spacecraft pitched down 34 degrees.) He then tested manual control of yaw and roll. When he took control of all three axes, he found that the spacecraft response was about the same as that of the Mercury simulator.

He then made observations outside the spacecraft using the two porthole windows and the periscope. He saw the outlines of the west coast of Florida and the Gulf of Mexico. Lake Okeechobee in central Florida was also visible, but he could not see any city. Andros Island and the Bahamas were also observed in the periscope.

The retrorockets were fired at about T+5 minutes and 15 seconds into the flight, shortly after the spacecraft reached an apogee of 116.5 miles (187.5 kilometres). The three 1,000 pounds-force (4,400 N) thrust retrograde rockets ripple-fired to provide a 510 ft/s (160 m/s) delta-V in the opposite direction of travel. Each retrorocket fired for a total of 10 seconds. They were fired five seconds apart so they overlap in burning (retro #1 fired at 5:14.1, retro #2 fired at 5:18.8 and retro #3 fired at 5:23.6 MET.) The retrorocket firing could be easily heard, but the noise was not as loud as the sound of the jet trainers Shepard had flown. The periscope was retracted at T+5 minutes and 45 seconds and the retropack was jettisoned at about T+6 minutes and 13.6 seconds. After retrofire the nose of the spacecraft was pitched up to a 14 degree from Earth-vertical attitude for reentry. This happened at about T+6 minutes and 20 seconds.

View from inside the capusle

During the descent, Shepard tried to look out the awkwardly-placed porthole windows to observe the stars. He could see nothing, not even the horizon. At about T+7 minutes and 48.2 seconds, the 0.05 g (0.5 m/s²) light came on, an indication that the acceleration buildup was about to start. The Automatic Stabilization & Control System (ASCS) detected the beginning of reentry and initiated a 10 deg/s roll. This maneuver makes the spacecraft more stable during reentry. During reentry a peak of 11.6 g (114 m/s²) was reached.

At 21,000 ft (6.4 km) about T+9 minutes and 38.1 seconds after launch, the drogue parachute came out. At 15,000 ft (4.6 km) a snorkel valve opened to equalize cabin pressure with the outside air. At 10,000 ft (3.0 km), about T+10 minutes and 14.8 seconds into the flight, the antenna canister at the top of the spacecraft jettisoned as planned, pulling out the main parachute. About five seconds later, the beryllium heatshield dropped down 4 feet (1.2 m), extending the landing bag under the spacecraft. Freedom 7 was descending under the parachute at 35 ft/s (11 m/s).

HUS-1 helicopter from Lake Champlain recovering Alan Shepard from the Freedom 7 capsule.

Splashdown occurred at T+15 minutes and 22.0 seconds. Water impact was comparable to landing a jet aircraft on an aircraft carrier. Freedom 7 tilted over on the right side about 60 degrees from an upright position. Shepard checked the spacecraft interior for leaks, but found none. Slowly, Freedom 7 came to an upright position, taking about a minute to do so.

Recovery of Freedom 7 by a HMM-262 Seabat from the USS Lake Champlain

A recovery helicopter that watched Freedom 7 for five minutes of its descent now came overhead and hooked a cable to the top of the spacecraft. The helicopter crew was in radio communications with Shepard. The astronaut indicated he would release the spacecraft hatch when it cleared the water. The helicopter pulled the spacecraft a couple of feet (about 1 m) higher in the water and Shepard released the hatch. A sling was lowered to the astronaut and he was lifted into the helicopter. Both Shepard and the Freedom 7 were then flown to the deck of the nearby recovery carrier, the USS Lake Champlain. They were on board the carrier 11 minutes after landing in the water. The astronaut and spacecraft came through the flight in fine shape.

The flight lasted 15 minutes, 28 seconds and the spacecraft traveled 302 miles (486 kilometres) from its launch point, ascending to 116.5 miles (187.5 kilometres). Freedom 7 landed at these coordinates: 27°14′N 75°53′W / 27.23°N 75.88°W / 27.23; -75.88. It reached a speed of 5,180 mph (8,340 km/h). During the launch phase, Shepard experienced 6.3 g (62 m/s²) and during reentry 11.6 g (114 m/s²).

Following the flight the spacecraft was examined by engineers and found to be in excellent shape, so much so that they decided it could have been safely used again in another launch. The Freedom 7 is now on display in the lobby of the Armel-Leftwich Visitor Center at the U.S. Naval Academy, Annapolis, MD. It was placed there after Shepard's death in 1998.

In June 1961, Laurie Records issued a 45 rpm single featuring William Allen and Orchestra entitled "Space Flight Freedom 7." It consisted of recreations of the tower to astronaut communications spoken over an instrumental backing. The Mercury-Redstone 3 mission was dramatized in the HBO miniseries From the Earth to the Moon episode "Can We Do This?" (starring Ted Levine as Alan Shepard), as well as in Tom Wolfe's book The Right Stuff, and Philip Kaufman's movie The Right Stuff based on the book. (In Kaufman's film, Scott Glenn plays Shepard.)

Flight events

T+ Time Event Description
T+00:00:00 Liftoff Mercury-Redstone lifts off, onboard clock starts.
T+00:00:16 Pitch Program Redstone pitches over 2 deg/s from 90 deg to 45 deg.
T+00:00:40 End Pitch Program Redstone reaches 45 deg pitch.
T+00:01:24 Max Q Maximum dynamic pressure ~575 lbf/ft² (28 kPa).
T+00:02:20 BECO Redstone engine shutdown - Booster Engine Cutoff. Velocity 5,200 mph (2.3 km/s)
T+00:02:22 Tower Jettison Escape Tower Jettison, no longer needed.
T+00:02:24 Spacecraft Separation Posigrade rockets fire for 1 s giving 15 ft/s (4.6 m/s) separation.
T+00:02:35 Turnaround Maneuver Spacecraft (ASCS) system rotates spacecraft 180 degrees, to heat shield forward attitude. Nose is pitched down 34 degrees to retro fire position.
T+00:05:00 Apogee Apogee of about 115 miles (185 kilometres) reached at 150 miles (240 kilometres) downrange from launch site.
T+00:05:15 Retrofire Three retro rockets fire for 10 seconds each. They are started at 5 second intervals, firing overlaps. Delta v of 550 ft/s (170 m/s) is taken off forward velocity.
T+00:05:45 Retract Periscope Periscope is automatically retracted in preparation for reentry.
T+00:06:15 Retro Pack Jettison One minute after retrofire retro pack is jettisoned, leaving heat shield clear.
T+00:06:20 Retro Attitude Maneuver (ASCS) orients spacecraft in 34 degrees nose down pitch, 0 degrees roll, 0 degrees yaw.
T+00:07:15 0.05 g (0.5 m/s²) Maneuver (ASCS) detects beginning of reentry and rolls spacecraft at 10 deg/s to stabilize spacecraft during reentry.
T+00:09:38 Drogue Parachute Deploy Drogue parachute deployed at 22,000 ft (6.7 km) slowing descent to 365 ft/s (111 m/s) and stabilizing spacecraft.
T+00:09:45 Snorkel Deploy Fresh air snorkel deploys at 20,000 ft (6.1 km). (ECS) switches to emergency oxygen rate to cool cabin.
T+00:10:15 Main Parachute Deploy Main parachute deploys at 10,000 ft (3.0 km). Descent rate slows to 30 ft/s (9.1 m/s)
T+00:10:20 Landing Bag Deploy Landing bag deploys, dropping heat shield down 4 ft (1.2 m).
T+00:10:20 Fuel Dump Remaining hydrogen peroxide fuel automatically dumped.
T+00:15:30 Splashdown Spacecraft lands in water about 300 mi (480 km) downrange from launch site.
T+00:15:30 Rescue Aids Deploy Rescue aid package deployed. The package includes green dye marker, recovery radio beacon and whip antenna.
Shepard in Freedom 7 Pilot & craft after recovery
Prep for launch

See also

References

  1. ^ "Chapter 11: Sub-orbital Flights, Section 1" (HTML). This New Ocean: A History of Project Mercury. NASA. 1964. Retrieved 2009-05-06. {{cite web}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  2. ^ "Project Mercury's Target Date Still Tuesday, May 2nd", Lodi News-Sentinel, Apr 29, 1961
  3. ^ "NASA Project Mercury Mission MR-3" (HTML). NASA, Kennedy Space Center. 2000-08-25. Retrieved 2009-05-05. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help)
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