Mercury-Redstone 4

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Mercury-Redstone 4
Grissom Climbs into Liberty Bell 7 - GPN-2002-000048.jpg
Astronaut Gus Grissom climbs into Liberty Bell 7
Mission typeTest flight
Operator NASA
Mission duration15 minutes, 37 seconds [1]
Range262.50 nautical miles (486.15 km)
Apogee102.76 nautical miles (190.31 km)
Spacecraft properties
Spacecraft Mercury No.11
Manufacturer McDonnell Aircraft
Launch mass2,835 pounds (1,286 kg)
Crew size1
CallsignLiberty Bell 7
Start of mission
Launch dateJuly 21, 1961, 12:20:36 (1961-07-21UTC12:20:36Z) UTC
Rocket Redstone MRLV MR-8
Launch site Cape Canaveral LC-5
End of mission
Recovered by USS Randolph
Landing dateJuly 21, 1961, 12:36:13 (1961-07-21UTC12:36:14Z) UTC
Landing siteNorth Atlantic Ocean
27°32′9″N75°45′57″W / 27.53583°N 75.76583°W / 27.53583; -75.76583
Liberty bell insignia.jpg
Spacecraft name as painted on capsule side, with a "crack"
Grissom prepares to enter Liberty Bell 7 61-MR4-76.jpg
Virgil Ivan "Gus" Grissom
Project Mercury
Crewed missions

Mercury-Redstone 4 was the second United States human spaceflight, on July 21, 1961. The suborbital Project Mercury flight was launched with a Mercury-Redstone Launch Vehicle, MRLV-8. The spacecraft, Mercury capsule #11, was nicknamed the Liberty Bell 7. It was piloted by astronaut Virgil "Gus" Grissom.


The spaceflight lasted 15 minutes 30 seconds, reached an altitude of more than 102.8 nautical miles (190.4 km), and flew 262.5 nautical miles (486.2 km) downrange, landing in the Atlantic Ocean. The flight went as expected until just after splashdown, when the hatch cover, designed to release explosively in the event of an emergency, accidentally blew. Grissom was at risk of drowning, but was recovered safely via a U.S. Navy helicopter. The spacecraft sank into the Atlantic and was not recovered until 1999.


Position Astronaut
Pilot Virgil I. Grissom
First spaceflight

Backup crew

Position Astronaut
Pilot John Glenn

Mission parameters


The Liberty Bell 7 spacecraft, Mercury spacecraft #11, was designated to fly the second crewed suborbital flight in October 1960. It came off McDonnell's St. Louis production line in May 1960. Liberty Bell 7 was the first Mercury operational spacecraft with a centerline window instead of two portholes. It was closer to the final orbital version than was Alan Shepard's Freedom 7 . Dubbed Liberty Bell 7, it featured a white, diagonal, irregular paint stripe starting at the base of the capsule and extending about two-thirds toward the nose, emulating the crack in the famed Liberty Bell in Philadelphia, Pennsylvania.

Explosive hatch

MR-4 Explosive Hatch Diagram. (NASA) Mercury 4 Hatch.png
MR-4 Explosive Hatch Diagram. (NASA)

Liberty Bell 7 also had a new explosive hatch release. This would allow an astronaut to exit the spacecraft quickly in the event of an emergency. Emergency personnel could also trigger the explosive hatch from outside the spacecraft by pulling on an external lanyard. Both the pop-off hatch and the lanyard are standard features of ejection seats used in military aircraft, but in the Mercury design, the pilot still had to exit the craft himself, or be removed by emergency personnel. The original exit procedure was to climb out through the antenna compartment, after removing a small pressure bulkhead. This was a difficult and slow procedure. Removal of an injured or unconscious astronaut through the top hatch would be nearly impossible. The original side hatch was bolted shut with 70 bolts and covered with several spacecraft shingles, making it a slow process to open the original hatch.

McDonnell Aircraft engineers devised two different quick release hatches for the Mercury spacecraft. The first had a latch, and was used on Ham's (a chimpanzee) MR-2 and Shepard's MR-3 missions. The second design was an explosive release hatch. The quick release latching hatch weighed 69  lb (31  kg), too much of a weight addition to use on the orbital version of the spacecraft. The explosive hatch design used the 70 bolts of the original design, but each quarter-inch (6.35 mm) titanium bolt had a 0.06 in (1.5 mm) hole bored into it to provide a weak point. A mild detonating fuse (MDF) was installed in a channel between the inner and outer seal around the periphery of the hatch. When the MDF was ignited, the resulting gas pressure between the inner and outer seal would cause the bolts to fail in tension.

There were two ways to fire the explosive hatch during recovery. On the inside of the hatch was a knobbed plunger. The pilot could remove a pin and press the plunger with a force of 5 or 6  lbf (25  N). This would detonate the explosive charge, which would shear off the 70 bolts and propel the hatch 25 ft (7.6 m) away in one second. If the pin was left in place, a force of 40 lbf (180 N) was required to detonate the bolts. An outside rescuer could blow open the hatch by removing a small panel near the hatch and pulling a lanyard. The explosive hatch weighed 23 lb (10 kg).


The new trapezoidal window on Liberty Bell 7 replaced the two 10 in (250 mm) side portholes that were on Freedom 7. The Corning Glass Works of Corning, New York designed and developed the multilayered panes that comprised the new window. The outer pane was 0.35 in (8.9 mm) thick Vycor glass. It could withstand temperatures of 1,500 to 1,800 °F (820 to 980 °C). The inner pane was made of three inner glass panels bonded to form a single inner pane. One panel was a 0.17 in (4.3 mm) thick sheet of Vycor, while the others were tempered glass. This new window assembly was as strong as any part of the spacecraft pressure vessel.


The manual controls of Liberty Bell 7 incorporated a new rate stabilization control system. This allowed fine control of spacecraft attitude movements by small turns of the hand controller. Previously a lot of jockeying of the device was needed to maintain the desired attitude. This rate damping, or rate augmentation system, gave finer and easier handling qualities and a redundant means of firing the pitch, yaw, and roll thrusters.

Before the Mercury-Redstone 4 mission, Lewis Research Center and Space Task Group engineers had determined that firing the posigrade rockets into the booster-spacecraft adapter, rather than in the open, developed 78 percent greater thrust. This achieved a greater spacecraft-booster separation through a kind of "pop-gun" effect. By using this technique, the spacecraft separated at velocity of about 28.1 ft/s (8.6 m/s) rather than 15 ft/s (4.6 m/s) using the old procedure. The Mercury-Redstone 4/Liberty Bell 7 mission would take advantage of this new procedure.

Additional hardware changes to Liberty Bell 7 were a redesigned fairing for the spacecraft-Redstone adapter clamp-ring and additional foam padding added to the head area of the contour couch. The fairing changes and additional foam were used to reduce vibrations the pilot experienced during the boost phase of flight. The spacecraft instrument panel was rearranged to provide a better eye scan pattern.

Mission description

In January 1961, NASA's Director of the Space Task Group, Robert Gilruth, told Gus Grissom that he would be the primary pilot for Mercury 4. John Glenn was the backup pilot for the mission.

Redstone launch vehicle MRLV-8 arrived at Cape Canaveral on June 8, 1961. A mission review on July 15, 1961, pronounced Redstone MRLV-8 and Mercury spacecraft #11 ready to go for the Mercury 4 mission.

Also, on July 15, 1961, Gus Grissom announced he would name Mercury 4, Liberty Bell 7. Grissom said the name was an appropriate call-sign for the bell-shaped spacecraft. He also said the name was synonymous with "freedom". As a tribute to the original Liberty Bell, a "crack" was painted on the side of the spacecraft.

The Mercury 4 mission was planned as a repeat of MR-3. It was to reach an apogee of 116 mi (187 km). The planned range was 299 mi (481 km). Grissom would experience a maximum acceleration of 6.33 g (62 m/s2) and deceleration of 10.96 g (107 m/s2).

The launch of Liberty Bell 7 was first planned for July 16. The cloud cover was too thick and the launch was postponed until July 18. On July 18, it was again postponed due to weather. Both times, the pilot had not yet boarded the spacecraft. On July 19, 1961, Grissom was on board when the flight was delayed again due to weather. At that point, it had just 10 minutes 30 seconds to go before launch.

On the morning of July 21, 1961, Gus Grissom entered the Liberty Bell 7 at 8:58 UTC and the 70 hatch bolts were put in place. At 45 minutes prior to the scheduled launch, a pad technician discovered that one of the hatch bolts was misaligned. During a 30-minute hold that was called, McDonnell and NASA Space Task Group engineers decided that the 69 remaining bolts should be sufficient to hold the hatch in place and blow it at the appropriate time. The misaligned bolt was not replaced.

Liberty Bell 7 was launched at 12:20:36 UTC, July 21, 1961.


Launch of Mercury-Redstone 4 at Cape Canaveral Air Force Station Launch Complex 5 Mercury-Redstone 4 Launch MSFC-6414824.jpg
Launch of Mercury-Redstone 4 at Cape Canaveral Air Force Station Launch Complex 5

Grissom later admitted at the postflight debriefing that he was "a bit scared" at liftoff, but he added that he soon gained confidence along with the acceleration increase. Hearing the engine roar at the pedestal, he thought that his elapsed-time clock had started late. Like Shepard, he was amazed at the smooth quality of the liftoff, but then he noticed gradually more severe vibrations. These were never violent enough to impair his vision.

Grissom's cabin pressure sealed off at the proper altitude, about 27,000 ft (8.2 km), and he felt elated that the environmental control system was in good working order. The cabin and suit temperatures, respectively about 57.5 and 97 °F (14.2 and 36.1 °C) were quite comfortable. Watching his instruments for the pitch rate of the Redstone, Grissom saw it follow directions as programmed, tilting over at about one deg/s.

During a 3 g (29 m/s2) acceleration on the up-leg of his flight, Grissom noticed a sudden change in the color of the horizon from light blue to jet black. His attention was distracted by the noise of the tower-jettison rocket firing on schedule. Grissom felt the separation, and he watched the tower through the window as it drifted off, trailing smoke, to his right. At two minutes and 22 seconds after launch, the Redstone's Rocketdyne engine cut off after building a speed of 6,561 ft/s (2,000 m/s). Grissom had a strong sensation of tumbling during the transition from high to zero acceleration, and, while he had become familiar with this sensation in centrifuge training, for a moment he lost his bearings.

The Redstone coasted for 10 seconds after its engine cut off; then a sharp report signaled that the posigrade rockets were popping the spacecraft loose from the booster. Although Grissom peered out his window throughout his ship's turnaround maneuver, he never caught sight of his booster.

Ballistic flight

With turnaround accomplished, the Air Force jet pilot for the first time became a space pilot, assuming manual-proportional control. A constant urge to look out the window made concentrating on his control tasks difficult. He told Shepard back in Mercury Control that the panorama of Earth's horizon, presenting an 800 mi (1,300 km)[ clarification needed ] arc at peak altitude, was fascinating. His instruments rated a poor second to the spectacle below.

Turning reluctantly to his dials and control stick, Grissom made a pitch movement change, but was past his desired mark. He jockeyed the handcontroller stick for position, trying to damp out all oscillations, then made a yaw movement and went too far in that direction. By the time the proper attitude was attained, the short time allocated for these maneuvers had been used, so he omitted the roll movement altogether. Grissom found the manual controls very sluggish when compared to the Mercury procedures trainer. He then switched to the new rate command control system and found perfect response, although fuel consumption was high.

After the pitch and yaw maneuvers, Grissom made a roll-over movement so he could see the ground from his window. Some land beneath the clouds (later determined to be western Florida around the Apalachicola area) appeared in the hazy distance, but the pilot was unable to identify it. Suddenly Cape Canaveral came into view so clearly that Grissom found it hard to believe that his slant-range was over 150 mi (240 km).[ clarification needed ]

He saw Merritt Island, the Banana River, the Indian River, and what appeared to be a large airport runway. South of Cape Canaveral, he saw what he believed to be West Palm Beach.


With Liberty Bell 7 at an altitude of 118.26 mi (190.32 km), it was now time to position the spacecraft in its reentry attitude. Grissom had initiated the retrorocket sequence and the spacecraft was arcing downward. His pulse reached 171 beats per minute. Retrofire gave him the distinct and peculiar feeling that he had reversed his backward flight through space and was actually moving face forward. As he plummeted downward, he saw what appeared to be two of the spent retrorockets pass across the periscope view after the retrorocket package had been jettisoned.

Pitching the spacecraft over into a reentry attitude of 14 degrees from Earth-vertical, the pilot tried to see the stars out his observation window. Instead the glare of sunlight filled his cabin, making it difficult to read the panel dials, particularly those with blue lights. Grissom thought that he would not have noticed the 0.05 g (0.5 m/s2) light if he had not known it was about to flash on.

Reentry presented no problem. Grissom could not feel the oscillations following the acceleration buildup; he could only read them on the rate indicators. Meanwhile, he continued to report to the Mercury Control Center on his electric current reading, fuel quantity, acceleration, and other instrument indications. Condensation and smoke trailed off the heatshield at about 65,000 ft (20 km) as Liberty Bell 7 plunged back into the atmosphere.

The drogue parachute deployed on schedule at 21,000 ft (6.4 km). Grissom said he saw the deployment and felt some resulting pulsating motion, but not enough to worry him. Main parachute deployment occurred at 12,300 ft (3.7 km), which was about 1,000 ft (300 m) higher than the design nominal altitude. Watching the main chute unfurl, Grissom spotted a 6 in (150 mm) L-shaped tear and another 2 in (51 mm) puncture in the canopy. Although he worried about them, the holes grew no bigger and his rate of descent soon slowed to about 28 ft/s (8.5 m/s). Dumping his peroxide control fuel, the pilot began transmitting his panel readings.


A "clunk" confirmed that the landing bag had dropped in preparation for impact. Grissom then removed his oxygen hose and opened his visor, but deliberately left the suit ventilation hose attached. Impact was milder than he had expected, although the spacecraft heeled over in the water until Grissom was lying on his left side. He thought he was facing downward. The spacecraft gradually righted itself, and, as the window cleared the water, Grissom jettisoned the reserve parachute and activated the rescue aids switch. Liberty Bell 7 still appeared to be watertight, although it was rolling badly with the swells.

Preparing for recovery, he disconnected his helmet and checked himself for debarkation. The neck dam did not unroll easily; Grissom tinkered with his suit collar to ensure his buoyancy in the event that he had to get out of the spacecraft quickly. When the recovery helicopters, which had taken to the air at launch time and visually followed the contrails and parachute descent, were still about 2 mi (3.2 km) from the impact point, which was only 3 mi (4.8 km) beyond the bullseye, Lieutenant James L. Lewis, the pilot of the primary recovery helicopter, radioed Grissom to ask if he was ready for pickup. He replied that he wanted them to wait five minutes while he recorded his cockpit panel data. Using a grease pencil with the pressure suit gloves was awkward, and several times the suit ventilation caused the neck dam to balloon, but Grissom simply placed his finger between neck and dam to allow the air to escape.

Hatch blows open

Grissom is hoisted to safety following the sinking of Liberty Bell 7 Grissom lifted from water 61-MR4-82.jpg
Grissom is hoisted to safety following the sinking of Liberty Bell 7

After logging the panel data, Grissom asked the helicopters to begin the approach for pickup. He removed the pin from the hatch-cover detonator and lay back in the couch. "I was lying there, minding my own business," he said afterward, "when I heard a dull thud." The hatch cover blew away, and salt water splashed into the spacecraft as it bobbed in the ocean. The capsule began taking on water and started to sink.

Grissom had difficulty recollecting his actions at this point, but he was certain that he had not touched the hatch-activation plunger. He had earlier unbuckled himself from most of his harness; he now removed his helmet, grasped the instrument panel with his right hand, and climbed though the hatchway.

The copilot of the nearest recovery helicopter said that as he was preparing, per procedure, to cut off the spacecraft's antenna whip with a squib-actuated cutter at the end of a pole, the hatch cover flew off, struck the water about 5 ft (1.5 m) away, then skipped over the waves. Next he saw Grissom climb through the hatch and swim away.

Failed spacecraft recovery

HUS-1 helicopter attempting to recover the Liberty Bell 7 spacecraft. The recovery ship USS Randolph is visible in the distance. Failed Attempt to Recover Liberty Bell 7 - GPN-2002-000047.jpg
HUS-1 helicopter attempting to recover the Liberty Bell 7 spacecraft. The recovery ship USS Randolph is visible in the distance.

Leaving aside the swimming astronaut, Lewis completed his approach to the sinking spacecraft, as both he and Reinhard were intent on spacecraft recovery. This action was a conditioned reflex based on past training experience. While training off the Virginia beaches the helicopter pilots had noted that the astronauts seemed at home in and to enjoy the water. So Reinhard quickly cut the high-frequency antenna as soon as the helicopter reached Liberty Bell 7. Throwing aside the antenna cutting device, Reinhard picked up the shepherd's-hook recovery pole and carefully threaded the crook through the recovery loop on top of the spacecraft. By this time Lewis had lowered the helicopter to assist Reinhard in his task to a point that the helicopter's three wheels were in the water. The capsule sank out of sight, but the pickup pole tangled as the attached cable went taut, indicating to the helicopter pilots that they had made the catch.

Reinhard immediately prepared to pass the floating astronaut the personnel hoist, but at that moment Lewis called a warning that a detector light had flashed on the instrument panel, indicating that metal chips were in the oil sump because of engine strain. Considering the implication of impending engine failure, Lewis told Reinhard to retract the personnel hoist while he called the second helicopter to retrieve Grissom.

Meanwhile, Grissom, having made certain that he was not snared by any lines, noticed that the primary helicopter was having trouble raising the submerged spacecraft. He swam back to the spacecraft to see if he could assist, but found the cable properly attached. When he looked up for the personnel line, he saw the helicopter start to move away.

Suddenly, Grissom realized that he was not riding as high in the water as he had been. All the time he had been in the water he kept feeling air escape through the neck dam. The more air he lost, the less buoyancy he had. Moreover, he had forgotten to secure his suit inlet valve. Swimming was becoming difficult, and now with the second helicopter moving in he found the rotor wash between the two aircraft was making swimming more difficult. Bobbing under the waves, Grissom was scared, angry, and looking for a swimmer from one of the helicopters to help him tread water. Then he caught sight of a familiar face, that of George Cox, aboard the second helicopter. Cox was the copilot who had retrieved both the chimpanzee Ham and Shepard on the first Mercury flight. With his head barely above water, Grissom found the sight of Cox heartening.

Cox tossed the "horse-collar" lifeline straight to Grissom, who immediately wrapped himself into the sling backwards. Lack of orthodoxy mattered little to Grissom now, for he was on his way to the safety of the helicopter, even though swells dunked him twice more before he got aboard. His first thought was to get a life preserver on. Grissom had been either swimming or floating for a period of only four or five minutes, "although it seemed like an eternity to me," as he said afterward.

As the first helicopter moved away from Grissom, it struggled to raise the spacecraft high enough to drain the water from the impact bag. At one point the spacecraft was almost clear of the water, but like an anchor it prevented the helicopter from moving forward. The flooded capsule weighed over 5,000 pounds (2,300 kg), 1,000 lb (450 kg) beyond the helicopter's lifting capacity. The pilot, watching his insistent red warning light, decided not to chance losing two craft in one day. He finally cast loose, allowing the spacecraft to sink swiftly. Martin Byrnes, aboard the carrier, suggested that a marker be placed at the point so that the spacecraft might be recovered later. Rear Admiral J. E. Clark advised Byrnes that in that area the depth was about 2,800 fathoms (5.1 km; 16,800 ft; 3.2 mi).


Substantial controversy ensued, as Grissom reported that the hatch had blown prematurely without his authorization. An independent technical review of the incident between August and October 1961 raised doubts regarding the theory that Grissom had blown the hatch and was responsible for the loss of the spacecraft. [2] There is strong evidence that the Astronaut Office did not accept Grissom's guilt in the fact that he was maintained in the prime rotation spot for future flights, commanding the first Gemini flight, and the first planned Apollo flight. [2]

Three Mercury flights later, Astronaut Wally Schirra manually blew Sigma 7's hatch after recovery when his spacecraft was on the deck of the recovery ship, in a deliberate attempt to dispel the rumor that Grissom might have blown the capsule's hatch deliberately. As anticipated, the kickback from the manual trigger left Schirra with a visible injury to his right hand. Grissom was uninjured when he exited the spacecraft, as documented by his postflight physical. This strongly supports his assertion that he did not accidentally hit the trigger, since in that case he would have been even more likely to injure himself than with intentional activation. [3]

In a 1965 interview, Grissom said that he believed the external release lanyard came loose, triggering the hatch release. On the Liberty Bell 7, this release lanyard was held in place by only one screw. This theory was accepted by Guenter Wendt, the Pad Leader for most early American crewed spaceflights. [4]

During a launch simulation on Apollo 1 in 1967, the combination of a cabin fire and an inward-opening hatch contributed to the death of Grissom, as well as that of the astronauts Ed White and Roger B. Chaffee in a launch-pad fire. Use of an explosive hatch had been rejected following the discovery by engineers that, in fact, an explosive egress system on a spacecraft could inadvertently fire without being triggered. Following the Apollo fire, Block II Apollo spacecraft were equipped with rapid-opening systems.

In 2021, analysis of video of the recovery suggested that static electricity may have caused the premature detonation of the hatch bolts. Helicopters are known to build up a charge of static electricity due to the rotors moving through the air. Marine Corps Lt. John Reinhard, the crewman aboard the helicopter who used a set of shears containing explosive charges to snip off the antenna on the floating spacecraft (to allow the helicopter to go lower) reported that “when I touched the antenna there was an arc, and both cutters fired. At the same time, the hatch came off. It could be that some static charge set [the hatch] off.” [5]

Recovery of Liberty Bell 7

Liberty Bell 7 was recovered in 1999 Liberty Bell 7 1999.jpg
Liberty Bell 7 was recovered in 1999
The restored spacecraft is currently displayed at the Cosmosphere in Hutchinson, Kansas. 2006LibertyBell7Display.JPG
The restored spacecraft is currently displayed at the Cosmosphere in Hutchinson, Kansas.

After several unsuccessful attempts in 1992 and 1993, Oceaneering International, Inc. lifted the Liberty Bell 7 off the floor of the Atlantic Ocean and onto the deck of a recovery ship on July 20, 1999, the 30th anniversary of the Apollo 11 lunar landing. [6] The team was led by Curt Newport and financed by the Discovery Channel. The spacecraft was found after a 14-year effort by Newport at a depth of nearly 16,000 ft (4,900 m), [7] 300 nmi (350 mi; 560 km) east-southeast of Cape Canaveral. [8] Among the items found within were part of the flight gear and several Mercury head dimes which were taken to space to be souvenirs of the flight. [6]

After Liberty Bell 7 was secured on the deck of the recovery ship, the "Ocean Project", experts removed and disposed of an explosive device (SOFAR bomb) that was supposed to detonate in the event of the spacecraft's sinking, but which failed to explode. [9] The spacecraft was then placed in a container filled with seawater to prevent further corrosion. The Cosmosphere, in Hutchinson, Kansas, disassembled and cleaned the spacecraft, [10] and it was released for a national tour through September 15, 2006. The spacecraft was then returned to the Cosmosphere where it is on permanent display. In 2016, it was temporarily lent to The Children's Museum of Indianapolis. [11]

Dramatization in film

Philip Kaufman's 1983 film The Right Stuff includes a dramatization of the Liberty Bell 7 mission in which Fred Ward played Gus Grissom. [12] Additional fictional representations also occur in HBO's 1998 From the Earth to the Moon with Mark Rolston as Gus Grissom and 2016's Hidden Figures movie with Devin McGee as Gus Grissom.


T+ TimeEventDescription
T+00:00:00LiftoffMercury-Redstone lifts off, onboard clock starts.
T+00:00:16Pitch ProgramRedstone pitches over 2 deg/s from 90 deg to 45 deg.
T+00:00:40End Pitch ProgramRedstone reaches 45 deg pitch.
T+00:01:24Max QMaximum dynamic pressure ~575 lbf/ft² (28 kPa).
T+00:02:20BECORedstone engine shutdown - Booster Engine Cutoff. Velocity 5,200 mph (2.3 km/s)
T+00:02:22Tower JettisonEscape Tower Jettison, no longer needed.
T+00:02:24Spacecraft SeparationPosigrade rockets fire for 1 s giving 15 ft/s (4.6 m/s) separation.
T+00:02:35Turnaround ManeuverSpacecraft (ASCS Automatic Stabilization and Control System) system rotates spacecraft 180 deg, to heat shield forward attitude. Nose is pitched down 34 deg to retro fire position.
T+00:05:00ApogeeApogee of about 115 mi (185 km) reached at 150 mi (240 km) downrange from launch site.
T+00:05:15RetrofireThree retro rockets fire for 10 s each. They are started at 5 s intervals, firing overlaps. Delta-V of 550 ft/s (170 m/s) is taken off forward velocity.
T+00:05:45Retract PeriscopePeriscope is automatically retracted in preparation for reentry.
T+00:06:15Retro Pack JettisonOne minute after retrofire retro pack is jettisoned, leaving heatshield clear.
T+00:06:20Retro Attitude Maneuver(ASCS) orients spacecraft in 34 deg nose down pitch, 0 deg roll, 0 deg yaw.
T+00:07:15.05 g Maneuver(ASCS) detects beginning of reentry and rolls spacecraft at 10 deg/s to stabilize spacecraft during reentry.
T+00:09:38Drogue Parachute DeployDrogue parachute deployed at 22,000 ft (6.7 km) slowing descent to 365 ft/s (111 m/s) and stabilizing spacecraft.
T+00:09:45Snorkel DeployFresh air snorkel deploys at 20,000 ft (6.1 km). (ECS) switches to emergency oxygen rate to cool cabin.
T+00:10:15Main Parachute DeployMain parachute deploys at 10,000 ft (3.0 km). Descent rate slows to 30 ft/s (9.1 m/s)
T+00:10:20Landing Bag DeployLanding Bag Deploys, dropping heat shield down 4 ft (1.2 m).
T+00:10:20Fuel DumpRemaining hydrogen peroxide fuel automatically dumped.
T+00:15:30SplashdownSpacecraft lands in water about 300 mi (480 km) downrange from launch site.
T+00:15:30Rescue Aids DeployRescue aid package deployed. The package includes green dye marker, recovery radio beacon and whip antenna.

See also


  1. "Results Of The Second U.S. Manned Suborbital Spaceflight July 21, 1961 (NASA)". NASA. 1961.
  2. 1 2 Ben Evans (April 2, 2010). Escaping the Bonds of Earth: The Fifties and the Sixties. Springer Science & Business Media. pp. 107–. ISBN   978-0-387-79094-7.
  3. French, F.; Burgess, C. (2007). Into That Silent Sea: Trailblazers of the Space Era, 1961-1965, Lincoln: University of Nebraska Press ( ISBN   978-0-8032-1146-9), 93
  4. John Bisney; J. L. Pickering (April 25, 2016). Spaceshots and Snapshots of Projects Mercury and Gemini: A Rare Photographic History. University of New Mexico Press. pp. 15–. ISBN   978-0-8263-5263-7.
  5. "Did static electricity — not Gus Grissom — blow the hatch of the Liberty Bell 7 spacecraft?". July 21, 2021. Retrieved July 23, 2021.
  6. 1 2 Joseph A. Angelo (May 14, 2014). Human Spaceflight. Infobase Publishing. pp. 87–. ISBN   978-1-4381-0891-9.
  7. Ocean News & Technology. Technology Systems Corporation.
  8. Air & Space Smithsonian. Smithsonian Institution. 2000.
  9. Materials Performance. National Association of Corrosion Engineers. July 1999.
  10. Robert Greenberger (October 1, 2003). Gus Grissom: The Tragedy of Apollo 1. The Rosen Publishing Group. pp. 54–. ISBN   978-0-8239-4458-3.
  11. "The Liberty Bell 7 Recovery". Blacksburg, Virginia: UXB. 2011. Archived from the original on June 19, 2012. Retrieved March 18, 2013.
  12. Emmis Communications (October 2000). Indianapolis Monthly. Emmis Communications. pp. 102–. ISSN   0899-0328.

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Splashdown Method of landing a spacecraft by parachute in a body of water

Splashdown is the method of landing a spacecraft by parachute in a body of water. It was used by crewed American spacecraft prior to the Space Shuttle program, by SpaceX Dragon and Dragon 2 capsules, and is planned for use by the upcoming Orion Multipurpose Crew Vehicle. It is also possible for the Russian Soyuz spacecraft to land in water, though this is only a contingency. The only example of an unintentional crewed splashdown in Soviet history is the Soyuz 23 landing.

<i>The Right Stuff</i> (film) 1983 film by Philip Kaufman

The Right Stuff is a 1983 American epic historical drama film written for the screen and directed by Philip Kaufman. It is based on the 1979 book of the same name by Tom Wolfe. It follows the Navy, Marine, and Air Force test pilots who were involved in aeronautical research at Edwards Air Force Base, California, as well as the Mercury Seven, the seven military pilots who were selected to be the astronauts for Project Mercury, the first human spaceflight by the United States. The film stars Sam Shepard, Ed Harris, Scott Glenn, Fred Ward, Dennis Quaid, and Barbara Hershey. Levon Helm narrates and plays Air Force test pilot Jack Ridley.

Gemini 3 1965 American crewed space mission

Gemini 3 was the first crewed mission in NASA's Gemini program. On March 23, 1965, astronauts Gus Grissom and John Young flew three low Earth orbits in their spacecraft, which they nicknamed Molly Brown. This was the ninth crewed US spaceflight, and the 17th world human spaceflight including eight Soviet flights. It was also the final crewed flight controlled from Cape Kennedy Air Force Station in Florida, before mission control functions were shifted to a new control center located at the newly opened Manned Spacecraft Center in Houston, Texas.

Mercury-Redstone 3 First United States human spaceflight, on May 5, 1961

Mercury-Redstone 3, or Freedom 7, was the first United States human spaceflight, on May 5, 1961, piloted by astronaut Alan Shepard. It was the first crewed flight of Project Mercury. The project had the ultimate objective of putting an astronaut into orbit around the Earth and return him safely. Shepard's mission was a 15-minute suborbital flight with the primary objective of demonstrating his ability to withstand the high g-forces of launch and atmospheric re-entry.

Mercury-Atlas 6 First American orbital spaceflight

Mercury-Atlas 6 (MA-6) was the first American orbital spaceflight, which took place on February 20, 1962. Piloted by astronaut John Glenn and operated by NASA as part of Project Mercury, it was the fifth human spaceflight, preceded by Soviet orbital flights Vostok 1 and 2 and American sub-orbital flights Mercury-Redstone 3 and 4.

Mercury-Atlas 7 1962 crewed spaceflight within NASAs Project Mercury

Mercury-Atlas 7, launched May 24, 1962, was the fourth crewed flight of Project Mercury. The spacecraft, named Aurora 7, was piloted by astronaut Scott Carpenter. He was the sixth human to fly in space. The mission used Mercury spacecraft No. 18 and Atlas launch vehicle No. 107-D.

Mercury-Atlas 8 Manned NASA spacecraft

Mercury-Atlas 8 (MA-8) was the fifth United States crewed space mission, part of NASA's Mercury program. Astronaut Walter M. Schirra Jr., orbited the Earth six times in the Sigma 7 spacecraft on October 3, 1962, in a nine-hour flight focused mainly on technical evaluation rather than on scientific experimentation. This was the longest U.S. crewed orbital flight yet achieved in the Space Race, though well behind the several-day record set by the Soviet Vostok 3 earlier in the year. It confirmed the Mercury spacecraft's durability ahead of the one-day Mercury-Atlas 9 mission that followed in 1963.

Gordon Cooper American astronaut

Leroy Gordon "Gordo" Cooper Jr. was an American aerospace engineer, test pilot, United States Air Force pilot, and the youngest of the seven original astronauts in Project Mercury, the first human space program of the United States. Cooper learned to fly as a child, and after service in the United States Marine Corps during World War II, he was commissioned into the United States Air Force in 1949. After service as a fighter pilot, he qualified as a test pilot in 1956, and was selected as an astronaut in 1959.

Gemini 4 Second crewed space flight in NASAs Project Gemini

Gemini 4 was the second crewed spaceflight in NASA's Project Gemini, occurring in June 1965. It was the tenth crewed American spaceflight. Astronauts James McDivitt and Ed White circled the Earth 66 times in four days, making it the first US flight to approach the five-day flight of the Soviet Vostok 5. The highlight of the mission was the first space walk by an American, during which White floated free outside the spacecraft, tethered to it, for approximately 20 minutes.

Mercury-Atlas 5

Mercury-Atlas 5 was an American spaceflight of the Mercury program. It was launched on November 29, 1961, with Enos, a chimpanzee, aboard. The craft orbited the Earth twice and splashed down about 200 miles (320 km) south of Bermuda, and Enos became the first primate from the United States and the third great ape to orbit the Earth.

Mercury Seven Group of seven Mercury astronauts

The Mercury Seven were the group of seven astronauts selected to fly spacecraft for Project Mercury. They are also referred to as the Original Seven and Astronaut Group 1. Their names were publicly announced by NASA on April 9, 1959. These seven original American astronauts were Scott Carpenter, Gordon Cooper, John Glenn, Gus Grissom, Wally Schirra, Alan Shepard, and Deke Slayton. The Mercury Seven created a new profession in the United States, and established the image of the American astronaut for decades to come.

Mercury-Redstone 1A

Mercury-Redstone 1A (MR-1A) was launched on December 19, 1960 from LC-5 at Cape Canaveral, Florida. The mission objectives of this uncrewed suborbital flight were to qualify the spacecraft for space flight and qualify the system for an upcoming primate suborbital flight. The spacecraft tested its instrumentation, posigrade rockets, retrorockets and recovery system. The mission was completely successful. The Mercury capsule reached an altitude of 130 miles (210 km) and a range of 235 miles (378 km). The launch vehicle reached a slightly higher velocity than expected - 4,909 miles per hour (7,900 km/h). The Mercury spacecraft was recovered from the Atlantic Ocean by recovery helicopters about 15 minutes after landing. Serial numbers: Mercury Spacecraft #2 was reflown on MR-1A, together with the escape tower from Capsule #8 and the antenna fairing from Capsule #10. Redstone MRLV-3 was used. The flight time was 15 minutes and 45 seconds.

Mercury-Redstone 2 1961 American space flight

Mercury-Redstone 2 (MR-2) was the test flight of the Mercury-Redstone Launch Vehicle just prior to the first manned American space mission in Project Mercury. Carrying a chimpanzee named Ham on a suborbital flight, Mercury spacecraft Number 5 was launched at 16:55 UTC on January 31, 1961 from LC-5 at Cape Canaveral, Florida. The capsule and Ham landed safely in the Atlantic Ocean 16 minutes and 39 seconds after launch.

Project Gemini 1961–1966 United States human spaceflight program, aimed at development of advanced spaceflight techniques

Project Gemini was NASA's second human spaceflight program. Conducted between projects Mercury and Apollo, Gemini started in 1961 and concluded in 1966. The Gemini spacecraft carried a two-astronaut crew. Ten Gemini crews and 16 individual astronauts flew low Earth orbit (LEO) missions during 1965 and 1966.

Space capsule Type of spacecraft

A space capsule is an often-crewed spacecraft that uses a blunt-body reentry capsule to reenter the Earth's atmosphere without wings. Capsules are distinguished from satellites primarily by the ability to survive reentry and return a payload to the Earth's surface from orbit. Capsule-based crewed spacecraft such as Soyuz or Orion are often supported by a service or adapter module, and sometimes augmented with an extra module for extended space operations. Capsules make up the majority of crewed spacecraft designs, although one crewed spaceplane, the Space Shuttle, has flown in orbit.

<i>The Right Stuff</i> (book) Book by Tom Wolfe

The Right Stuff is a 1979 book by Tom Wolfe about the pilots engaged in U.S. postwar research with experimental rocket-powered, high-speed aircraft as well as documenting the stories of the first Project Mercury astronauts selected for the NASA space program. The Right Stuff is based on extensive research by Wolfe, who interviewed test pilots, the astronauts and their wives, among others. The story contrasts the "Mercury Seven" and their families with other test pilots such as Chuck Yeager, who was considered by many contemporaries as the best of them all, but who was never selected as an astronaut.


PD-icon.svg This article incorporates  public domain material from websites or documents ofthe National Aeronautics and Space Administration .