Mercury Redstone 2

Mission dates

Mission:

Mercury-Redstone 2 (MR-2)

COSPAR-ID :

MERCR2

Spacecraft:

Serial number 5

Launcher:

Redstone Mercury MRLV-2

Crew:

1 chimpanzee

Begin:

January 31, 1961, 16:55 UTC

Starting place:

LC-5 , Cape Canaveral

Landing:

January 31, 1961, 17:12 UTC

Landing place:

Atlantic

Flight duration:

16min 39s

Earth orbits:

suborbital flight

Recovery ship:

USS Donner

Apogee :

157 km

Covered track:

679 km

Maximum speed:

9426 km / h

Maximum acceleration:

14.7 g

Team photo

Chimpanzee Ham is greeted on the rescue ship

◄ Before / After ►

Mercury Redstone 1A

Mercury Atlas 2

Mercury-Redstone 2 (MR-2) was the name for a suborbital test flight by NASA as part of the US Mercury program . It was the dress rehearsal for the USA's first manned space flight. The chimpanzee Ham was on board .

situation

By early 1961, NASA had almost achieved its goal of launching an astronaut into space. A flight of the Mercury spaceship was planned for this, which was to be brought to a suborbital trajectory by a Redstone rocket.

Before this first manned space flight, however, a test with a chimpanzee on board was necessary. The preparations and the flight history of this mission MR-2 were identical to the planned flight MR-3, which was to have a person on board for the first time.

The Soviet Union was also working on putting a human into space at the time, but refrained from suborbital flights. With prototypes of the Vostok spaceship , two dogs had already been put into orbit and recovered alive, although there were two failures in December 1960.

preparation

The rocket

A further development of the military Redstone missile, the Redstone Mercury , also called Redstone MRLV , was used for the manned suborbital flights of the Mercury Project .

The single-stage rocket with serial number 2 was brought to Cape Canaveral by air on December 20, 1960.

The spaceship

The Mercury spacecraft with the serial number 5 was manufactured at McDonnell in St. Louis . On September 3, 1960, it was flown to the Marshall Space Flight Center in Huntsville , where compatibility tests with the Redstone rocket were carried out. The capsule was then transported to Cape Canaveral on October 11th.

Compared to its predecessors, the Mercury spaceship with the serial number 5 had some new features:

the life support system
the position control
Braking missiles
Radiotelephony
the demolition security system
a pneumatic landing pad that was supposed to cushion the impact when it splashed down.

Two telemetry transmitters were installed in the capsule, making eight data channels available: three for medical values (pulse, respiratory rate, breathing depth), five for technical values (capsule temperature, internal temperature, pressure, noise, vibration).

The chimpanzee

MR-2 was not the first missile launch with a monkey on board. Test flights with these animals have been carried out in the USA since 1948. In the Mercury program, too, two suborbital flights with rhesus monkeys had previously taken place: Mercury-Little-Joe 2 in December 1959 and Mercury-Little-Joe 1B in January 1960, both from the Wallops Flight Facility .

With MR-2, however, the complete program of a ballistic space flight with an animal on board was to be carried out for the first time. A chimpanzee was chosen because these animals are most similar to humans in terms of their physique and reactions.

At Holloman Air Force Base in New Mexico , the US Air Force had long held chimpanzees for experiments. Six of them (four females and two males) were brought to Cape Canaveral on January 2, 1961, together with their caretakers. There they were kept in two separate groups to prevent infectious diseases from affecting the whole group.

The chimpanzees were trained for several weeks to push certain levers in spaceship dummies. If they reacted correctly, they were rewarded with bananas. If they did not respond in time, they were given light electric shocks.

The day before the flight, two of the six animals were selected: the male Ham as the first choice and the female Minnie as the reserve. The decision was made based on medical examinations and the reaction test. Four hours before the scheduled launch, Ham was fitted with a spacesuit and brought on board the spaceship 90 minutes before the launch.

The name "Ham" was on the one hand the abbreviation for the Holloman Aerospace Medical Center, where the chimpanzees were kept and trained, and on the other hand an allusion to the local laboratory manager, Hamilton Blackshear.

Trajectory

The previous Mercury-Redstone 1A mission had a steep flight path in December 1960 and had been severely deviated from the planned course by high winds. A flatter trajectory with about five minutes of weightlessness was therefore planned for MR-2. It was not intended to orbit the earth.

Re-entry was planned so that delays of around 12g should occur. There were two reasons for this: firstly, delays of 11 to 12 g should also occur in later suborbital flights of the Mercury-Redstone, and secondly, this value was a good mean of two scenarios for manned orbiting the earth with Mercury-Atlas: a normal reentry would take about 8 g bring, in the worst case 16 g.

Salvage

MR-2 was the first flight with a living being that took off from Cape Canaveral. Previous flights with monkeys on board had been operated from the Wallops Flight Facility . Thus, special precautions had to be taken to retrieve the spaceship quickly and safely.

In the event of a false start, amphibious vehicles and helicopters were available near the beach. The support ship USS Opportune was in position near the coast . Six destroyers and a dock landing ship with three helicopters on board crossed in the area of the planned target point . If the capsule should go down far from the target, four P2V reconnaissance aircraft could be activated.

Flight history

countdown

A split count has been introduced for the countdown . The countdown consists of two halves that are separated by a pause. The day before takeoff, the countdown began at T-640 minutes. At T-390 minutes, the clock was stopped and all systems were put to sleep. The next day the countdown continued with T-390 minutes. This countdown with fixed pauses is still used today in American space travel.

During the morning of January 31, 1961, an overheated repeater caused several interruptions in the countdown. The delays added up to several hours. In order to guarantee a recovery in daylight, the rocket had to be launched by around noon, otherwise the flight would have to be postponed to the following day.

flight

Start of Mercury-Redstone 2

The Redstone rocket took off five minutes to noon. After just one minute, a slight course deviation was registered: the rocket rose 1 ° too steeply, and the difference increased. The acceleration was 17 g.

Two minutes and 17 seconds after take-off, three seconds earlier than planned, the liquid oxygen was used up and the engine switched off. Six minutes of weightlessness began for Ham . The Mercury spacecraft separated from the rocket. A pressure equalization valve opened prematurely and the air escaped from the landing capsule. Within a short time, the pressure dropped to a fifth. However, Ham was in no danger because he was in a separate pressure capsule with its own supply system.

When the rescue rocket was blown off, the brake rockets also came off prematurely, which should later become noticeable with lower air resistance when reentrying. The automatic measures in this flight phase also included a radio message to the rescue fleet. In addition, the spaceship turned into the correct position.

During the entire duration of the flight, Ham had to operate levers with light signals with his left or right hand. In around 60 attempts, he only failed to press the lever in time twice. His reaction time was only slightly longer than during tests on the ground.

Five minutes after take-off, the trajectory reached its highest point at 252 km. Film cameras showed an unexpectedly large amount of dust and foreign bodies floating in the capsule. Apparently not enough attention was paid to cleanliness. Shortly after the apex of the orbit, the periscope, which was on board but was not used, was automatically retracted.

Ditching and salvage

At an altitude of 6,700 meters, the auxiliary parachute opened, slowing the landing capsule to a speed of 111 m / s. The main parachute then unfolded at 3000 meters, reducing the rate of descent to 9 m / s.

The Mercury capsule landed 679 km from Cape Canaveral. A radio transmitter went into operation automatically, and green dye marked the landing site.

The first sighting of the capsule took place about 27 minutes after the waterfall from board a search aircraft. MR-2 swam upright in the ocean. Due to the course deviations during the flight, the distance to the next recovery ship USS Ellison was about 100 km, which meant a delay of about two hours. Therefore helicopters were requested from the Donner .

When the helicopters got to the landing site, the landing capsule was on its side, taking in water. On impact, the heat shield had damaged the bottom of the capsule and tore two holes in the fuselage. In addition, the pressure equalization valve, which had already opened before the ditching, allowed more water to enter. There was a risk that the capsule would sink and Ham drowned.

The helicopter crew managed to transport the Mercury capsule to the USS Donner and set it down on deck. Ham was still alive and in good shape.

Flight data

The trajectory differed significantly from the data calculated in advance. This was due to the following reasons:

During the transition from vertical flight to inclined flight, the Redstone rocket took a steeper path than planned,
the engine developed more thrust, which is why the fuel was used up earlier than planned,
the air resistance was lower because the brake rockets were dropped prematurely.

This led to major deviations in the flight path and watering far away from the planned zone.

	Achieved value	Planned value
Summit height	253 km	185 km
Range	679 km	466 km
Flight duration	16.5 min	14.25 min
Maximum speed	2618 m / s = 9426 km / h	1967 m / s = 7081 km / h
Duration of weightlessness	6 min 36s	4 min 54s
Heavy burden on re-entry	14.7 g	12 g

Significance to the Mercury program

Opinions on the Mercury-Redstone 2 flight were divided. On the one hand, the flight was a success because despite some problems, Ham was shot into space and recovered alive. This proved the feasibility of a suborbital flight with a person on board in principle. On the other hand, the problems that had occurred had to be carefully investigated before a person could take a seat in the Mercury spacecraft on the next flight.

In the case of the spaceship, this mainly affected the impact protection, which had to prevent damage to the capsule when it splashed down. For this purpose, additional drop tests were carried out, also with test persons on board.

More serious were the defects in the Redstone rocket, which had deviated from the planned course on both previous flights. Another unmanned test flight Mercury-Redstone BD had to be inserted on March 24, 1961.

The first American in space was Alan Shepard on May 5, 1961 on board Mercury-Redstone 3 . In the meantime, however, the Soviets had put Yuri Gagarin into orbit on April 12 .

The Mercury capsule from Mercury-Redstone 2 is currently on display at the California Science Center in Los Angeles .

The 2001 feature film Race to Space - Mission into the Unknown sets its fictional plot in the context of this space flight.

Web links

Commons : Mercury-Redstone 2 - collection of pictures, videos and audio files

NASA: MR-2: Ham Paves the Way (Chapter from "This New Ocean")
Report on the recovery on the website of the USS Donner (English)