Mercury-Redstone 2

Mercury - Redstone 2 (MR -2) was the name for a suborbital test flight of NASA as part of the U.S. Mercury program. These were at the dress rehearsal for the first manned space flight in the U.S.. On board was the chimpanzee Ham.

• 3.1 countdown
• 3.2 flight
• 3.4 Flight data

Situation

At the beginning of 1961, NASA had almost reached their goal to shoot an astronaut into space. The plan was for a flight of Mercury spacecraft, which was to be brought by a Redstone rocket on a suborbital trajectory.

Before this first manned spaceflight, but a test with a chimpanzee on board was still necessary. The preparations and the flight course of this mission MR-2 were identical to the planned flight MR-3, the first time should have a man on board.

The Soviet Union at this time worked also in bringing a man into space, but abandoned it on suborbital flights. With prototype of the Vostok spaceship two dogs have already been placed into orbit and been rescued alive again, and it came but also to two failures in December 1960.

Preparation

The rocket

For the manned suborbital flights of the Mercury project was a development of the military Redstone rocket used the Mercury Redstone, also called Redstone MRLV.

The single-stage rocket with the serial number 2 was launched on 20 December 1960 to air for Cape Canaveral.

The spacecraft

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

Compared to its predecessors the Mercury spacecraft had installed with the serial number 5 a few innovations:

• The life support system
• The position control
• Braking rockets
• Radio
• The demolition safety system

Two telemetry transmitters were installed in the capsule, who provided eight data channels: three for medicinal values ​​(pulse, respiratory rate, depth), five for technical values ​​(capsule temperature, indoor temperature, pressure, noise, vibration).

The chimpanzee

MR-2 was not the first rocket launch with a monkey on board. Test flights were conducted with these animals in the United States since 1948. Also in the Mercury program were previously two suborbital flights with rhesus monkeys on board instead: Mercury -Little Joe - 2 in December 1959, Mercury -Little Joe 1B in January 1960, both from the Wallops Flight Facility from.

In MR - 2, however, the complete program of a ballistic space flight with an animal on board should be performed for the first time. The choice fell on a chimpanzee, because these animals are most similar in physique and response to man.

On the Holloman Air Force Base in New Mexico has long chimpanzees kept the U.S. Air Force for testing. Of the six animals ( four females and two males ) were housed together with their supervisors to Cape Canaveral on January 2, 1961. There they were kept in two separate groups to avoid contagious diseases known to affect the whole group.

The chimpanzees were several weeks trained to press levers in certain spaceship dummies. They responded correctly, they were rewarded with bananas. Came her response is not timely, they received light electric shocks.

Only the day before the flight were selected from the six animals two: the male Ham as the first choice and the female Minnie as a reserve. The decision was made due to medical examinations and the reaction test. Four hours before the scheduled start Ham was equipped with a space suit and put on board the spaceship 90 minutes before the start.

The name " Ham " was both an abbreviation of the Holloman Aerospace Medical Center, where the chimps had been kept and trained, on the other hand also a nod to the local laboratory director Hamilton Blackshear.

Trajectory

The previous mission Mercury - Redstone 1A had destroyed the planned course in December 1960, a steep trajectory and was due to strong upper-level winds. For MR-2 because of a flatter trajectory was planned with about five minutes of weightlessness. A mission in orbit was not provided.

The reentry was planned so that delays of about 12 g should occur. This has two reasons: first, should in future suborbital flights of the Mercury - Redstone also be delays of 11 to 12 g, secondly, this value was a good means of two scenarios for manned orbits with Mercury - Atlas: a normal re-entry would be about 8 g with itself bring in the worst case, however, 16 g

Salvage

MR-2 was the first flight with a living being, who started from Cape Canaveral. Earlier flights with monkeys on board had been carried out by the Wallops Flight Facility from. Thus, special precautions had to be taken to recover the space ship quickly and safely.

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

History of the flight

Countdown

When a countdown Split -Count has been introduced. This is the count of two halves, which are separated by a pause. The day before the start of the countdown began at T -640 minutes. At T -390 minutes, the clock was stopped and brought all systems in an idle state. The next day, the countdown has continued with T -390 minutes. This countdown with fixed breaks is still used today in the American space program.

During the morning of January 31, 1961 caused an overheated converter for multiple interruptions of the countdown. The delays added up to several hours. To a rescue had to guarantee in daylight the rocket be launched until about noon, otherwise the flight would have to be postponed to the following day.

Flight

Five minutes before lunch took off the Redstone rocket. After a minute, a slight price variation has been registered: the rocket rose steeply to 1 °, and the difference widened. The acceleration was 17 g

2 minutes and 17 seconds after the start, three seconds earlier than planned, the liquid oxygen was consumed and the engine switched off. For Ham began six minutes of weightlessness. 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 fifth. However, Ham hovered not in danger because he was in a separate pressure capsule with its own supply system.

When the rescue rocket was blasted off, also the braking rockets came off prematurely, which should make later on re-entry with a lower air resistance is felt. The automatic action in this flight phase included a radio message to the salvage fleet. In addition, the spacecraft turned into the correct position.

During the entire flight duration Ham had to press the lever to light characters with the left or right hand. At about 60 attempts, he missed only twice, in time to press the lever. His reaction time was there only slightly longer than that of testing on the ground.

Five minutes after the start of the trajectory reached its highest point with 252 km. Film cameras showed there is an unexpectedly large amount of dust and debris that floated in the capsule. Obviously had not been careful enough cleanliness. Shortly after the peak of the web was the periscope was not used on board was automatically retracted.

In 6700 meters above sea level, the auxiliary parachute, which slowed the landing capsule to a speed of 111 m / s opened. At 3000 meters then deployed the main parachute at 9 m / s decreased the rate of descent.

The Mercury capsule splashed down 679 km from Cape Canaveral. A radio transmitter continued to operate automatically, also marked green dye the landing site.

The first sighting of the capsule was carried out about 27 minutes after splashdown on board of a search aircraft. MR-2 floated upright in the ocean. Through the course deviations during the flight but the distance was the nearest recovery ship USS Ellison about 100 km, which meant a delay of about two hours. Therefore helicopters were requested by the thunder.

When the helicopter arrived at the landing site, the landing capsule lay on his side and took on water. Upon impact, the heat shield had the capsule base damaged and ripped two holes in the hull. In addition, let the pressure equalization valve, which had opened before the splashdown, penetrate more water. There was a risk that the capsule sank and drowned Ham.

Flight data

The trajectory substantially deviated from the pre-computed data. This had the following reasons:

• During the transition from vertical flight in the helical flight, the Redstone rocket took a steeper path than a planned,
• The engine developed more thrust, so the fuel was consumed earlier than planned,
• The air resistance was lower, because the braking rockets were dropped prematurely.

This led to larger deviations in the flight path and to a splashdown far from the planned zone.

Importance for the Mercury Program

The opinions about the flight Mercury - Redstone 2 were divided. On one hand, the flight was a success because Ham was shot in spite of some problems in space and rescued alive. Thus, the basic feasibility of a suborbital flight with a human on board was proved. On the other hand, the problems encountered had to be carefully examined before the next flight a man in the Mercury spacecraft should take place.

When the spaceship particularly affected the impact protection, which had to prevent damage to the capsule at the splashdown. For this purpose, additional drop tests were carried out with test persons on board.

More serious were the defects of the Redstone rocket, which had deviated from the planned course with two previous flights. It had to be pushed on March 24, 1961, another unmanned test flight Mercury - Redstone BD.

The first American in space ended up being brought on May 5, 1961, Alan Shepard aboard Mercury - Redstone 3 Meanwhile, the Soviets had already on 12 April Yuri Gagarin into orbit.

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

The movie Race to Space - Mission to the Unknown from 2001 puts his fictional plot in the environment of this space flight.