EVA (Extra Vehicular Activities) Systems patch.
Jan 4, 2023
On March 18, 1965, Alexei Leonov was the first person to go into outer space. He retired from the ship by five meters, using only a five-meter safety rope for movement. If the cable had failed, there would have been a serious problem. There were no other options to return the astronaut to the spaceship.
Cosmonaut in a "horseshoe"
A risky experiment with access to open space showed that it is possible to stay there, but for a long stay overboard, it is necessary to create a special installation that would also be a lifeboat. The designers of plant No. 918 in Tomilin near Moscow (now the Zvezda Research and Production Enterprise) took up its development and created a device for moving and maneuvering an astronaut (UPMK).
Museum NPP "Zvezda" The device for moving and maneuvering the cosmonaut
Made in the shape of a horseshoe, UPMK seemed to hug the astronaut in the space suit. In front and behind were brake and accelerating blocks with 42 solid-fuel engines each. They were supposed to provide movement in a straight line. And changes in orientation in space, in other words, turns, in six degrees of freedom were provided by 14 compressed air nozzles.
It was assumed that with the help of the device, the cosmonaut could not only fly around his ship, but also approach the enemy spacecraft in order to conduct its examination, or, in professional terms, an inspection. It was possible to return "home" without the use of engines - by means of a winch and a super-strong cable.
This project was not destined to come true. For various reasons, it was not possible to test the device in flight.
Edward White's rocket pistol
The world's first apparatus for moving a person in outer space, tested outside the Earth, was a manual maneuvering device (HHMU, Hand-Helded Maneuvering Unit), created under the Gemini program. It ran on compressed oxygen.
Edward White with pistol-type transfer rig
Astronaut Edward White in 1965 tested the device in flight on the Gemini 5 spacecraft. In shape, it resembled a pistol, which you had to keep in your hand all the time. This turned out to be a serious shortcoming of the system, as it significantly limited the astronaut's performance in open space. In addition, the accuracy of movement was determined "by eye". In general, this project was also closed.
The backpack did not live up to expectations
The failure did not stop the Americans, and they created an AMU (Astronaut Maneuvering Unit) installation of a "knapsack" type. The fuel for its engines was 90 percent hydrogen peroxide. The mass of the AMU with the astronaut was about 185kg. Since the Gemini ship was very cramped, the installation was fixed on the outside of the ship's aggregate compartment. To use it, the astronaut, dressed in a spacesuit, had to depressurize the cabin and move along the handrails to the place where the apparatus was attached. After that, it was possible to separate from the ship and maneuver.
Astronaut Maneuvering Unit Backpack
The system was tested in June 1966 during the Gemini 9 flight. Having done all the preliminary procedures, astronaut Eugene Cernan went outside. He was connected to the ship by a safety cable, the length of which reached 43 meters. With great difficulty, he reached the "knapsack" and climbed into it. However, the grueling operation exhausted him. He sweated, the condensate got into his eyes and settled on the glass of the helmet. Eugene stopped seeing anything around. In addition, it turned out that his hands do not reach the control joystick.
As a result, Cernan completed his mission ahead of schedule, got rid of the installation and returned to the spaceship.
Three more devices were not in demand
During the flight of the Skylab orbital station in 1973, the Americans developed and tested three more installations for the flight of an astronaut in outer space. All tests were carried out inside the station, where the volume, unlike the ship, was sufficient.
Astronaut Gerald Carr testing ASMUs inside Skylab Station
The first ASMU was an improved version of the "knapsack" that Eugene Cernan did not submit to on the Gemini 9. The second pistol type HHMU is a modernized analogue of the same jet handle that was tested on the Gemini-5. The third FCMU installation involved the use of pedals connected by a stand to a seat resembling a bicycle saddle.
The astronauts liked the first two samples, while the third turned out to be unsuitable. However, experiments with personal vehicles after these tests subsided again.
Flying shuttle seat
In the early 1980s, the Space Shuttle manned transport system began to operate in the United States, which provided that astronauts would spend a lot of time in outer space. For this program, they developed a "space chair" MMU (Manned Maneuvering Unit, "Manned Maneuvering Unit"). Its 24 engines ran on compressed nitrogen.
Bruce McCandless in free flight in the MMU seat
Astronaut Bruce McCandless became the first tester: in February 1984, for the first time in the world, he retired from a spacecraft (Challenger shuttle) without a safety rope at a distance of 97.5 meters.
Later, the astronauts used this “chair” twice more in outer space. With its help, in April 1984, the SMM satellite was repaired directly in orbit, and in November of the same year, the WestarVI and PalapaВ2 satellites, which had not been able to fly away six months earlier, were caught and placed in the Challenger cargo compartment to return to Earth. from low orbit to geostationary orbit due to a malfunction of the upper stage.
It would seem that success opened bright prospects for the invention. But in January 1986, the unexpected happened: as a result of the explosion of the Challenger's fuel tank, it collapsed on launch and seven astronauts died. After this tragic event, the American leadership changed the focus in its space program, especially where it was about the safety of the astronaut. The concept of using the MMU was abandoned.
Soviet response
In the Soviet Union, after Alexei Leonov's spacewalk, it was decided that all work outside the spacecraft would be carried out without separation from the ship's hull. The astronauts had to insure themselves with halyards with carbines.
For the Energia-Buran program, a lot of curious equipment was created, including a completely autonomous version of the Orlan-DMA spacesuit, which worked without being “fastened” with a halyard to the ship’s power supply and communication systems. As with the shuttles, Russian designers assumed that cosmonauts would often be in outer space.
Alexander Serebrov (in a space suit) and Alexander Viktorenko master the "space chair" in training
Unlike the American "armchair" MMU, which ran on nitrogen, the Soviet cosmonaut vehicle (SPK) used compressed air stored in 20-liter cylinders at a pressure of 350 atmospheres, and had two modes. The first - economical - for work near the station. The second - forced - for quick jerks in case of saving a partner.
Tests of the SPK-21KS in open space were carried out in 1990 by cosmonauts Alexander Serebrov and Alexander Viktorenko during an expedition to the Mir orbital complex. On February 1, Serebrov entrenched himself in the SEC, located in the airlock compartment of the Kvant-2 module, then went outside and began to gradually move away from the complex at a distance of up to 33 meters. During the "walk" Serebrov, as expected, was fastened to the station with a safety line with a winch, which allowed him to return to the module in case of failure of the SEC.
On February 5, Alexander Viktorenko continued testing, maneuvering and moving away from Mir by 45 meters.
However, for a number of reasons (including the closure of the Energia-Buran program), the developed tool was not used in the future, and the cosmonauts still continue to work in outer space, insuring themselves with two halyards with carbines.
For security
In Russian times, the NPP "Zvezda" developed a cosmonaut rescue unit (USK) of a knapsack type. It did not serve for maneuvering, had a small supply of fuel and was a means of returning to the station an accidentally unhooked cosmonaut.
Russian safe in the Zvezda Museum
In 2001-2002, Zvezda completed testing and produced three flight models for transportation to the ISS. Delivery was planned to be carried out by one of the shuttles. But after the Columbia disaster in January 2003, shuttle flights were suspended for two years. It fell to the Russian Progress ships to supply the station with cargo. Since there were no other possibilities, every gram sent into space was considered “under a magnifying glass”. The Russian “satchel” was not listed as a priority cargo, and therefore its mission never took place.
One of the USK copies took its place in the museum of the enterprise.
A similar self-rescue unit is also in NASA's arsenal on the ISS. True, according to some experts, it is not easy to work with it: an astronaut in a bulky spacesuit who accidentally broke away from the station and is in a state of stress will have to stabilize, orient his body in space and return “to base” using only a one-handed control panel.
Automatic "safer"
Taking into account the accumulated experience, the specialists of NPP Zvezda began developing a more advanced model several years ago, where all operations for the return of a cosmonaut who has “torn off” from the station will be performed automatically.
American SAFER on an EMU suit
“This device is guaranteed to return the cosmonaut if he retired to a dangerous distance during a spacewalk,” Sergey Pozdnyakov, general director and chief designer of NPP Zvezda, described the novelty. - I pressed the button - and the rescue device returns the astronaut to the station. In this case, seconds count.
The head of the enterprise clarified that there is an idea to integrate the rescue system directly into the Orlan spacesuit, which is used to work in outer space. “He has a tough cuirass that allows him to do this,” Sergey Pozdnyakov is sure.
The trajectory of the return to the station will be provided by radio beacons, and the movement impulse will be set by 16 micromotors operating on compressed air. As it became known to the editors, a prototype of the Russian "seifer" has long been tested on a special stand on an air cushion, the rationality of this concept has been evaluated. All you need is the means to make it.
A satellite from Samara will save the astronaut
A completely different principle for rescuing an astronaut was recently proposed by the designers of the Samara National Research University named after S. P. Korolev. According to their idea, the robotic nanosatellite complex, which can be placed on the outer surface of the Russian orbital station being created, should save the cosmonauts. The complex includes a nanosatellite with a maneuvering unit, a device for its separation from the station, an electromechanical winch with a roll of a heavy-duty cable, a high-precision launch tracking device and an automated control system.
Samara engineers with a prototype nanosatellite rescuer
“Flying up to an astronaut in distress, the nanosatellite will automatically or with the help of the astronaut himself dock with the spacesuit docking device. At the same time, the maneuvering unit compensates for the rotation of the astronaut, after which the winch will turn on, winding the cable, and the astronaut will be delivered to the station, ”said Professor Igor Belokonov, head of the interuniversity department of space research at Samara University.
It is expected that in the near future Samara University will send a proposal to Roscosmos to include this development in the structure of the Russian orbital station.
Author: Igor Marinin
Translation: Roland Berga
The article was published in the Russian Space magazine.
ROSCOSMOS Press Release: https://www.roscosmos.ru/38623/
Images, Text (mentioned), Credits: ROSCOSMOS/NASA/Orbiter.ch Aerospace.
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