Sealab
Sealab was a series of three U.S. Navy scientific programs in 1964, 1965, and 1969 that included two underwater laboratories . The program began after the US Navy became aware of George F. Bond's proposals in 1963 for seabed stations.
Sealab I
Sealab I was inhabited by four people for 11 days at the end of July 1964 at a depth of 58.80 m (193 feet) in a helium-oxygen-nitrogen atmosphere below ambient pressure.
Was built Sealab I from mine clearance laboratory of the US Navy (US Navy Mine Defense Laboratory) in Panama City, Florida.
With Sealab I , the problems that arise while staying and performing work tasks under increased pressure should be tested in open sea conditions. The allotted time frame should be compared to that of conventional divers, including donning equipment, descent, work and ascent with decompression breaks. The results should confirm the results of laboratory tests on land.
The US Navy also stated that it wanted to catch up with the research results of Edwin A. Link's man-in-the-sea program and Jacques Cousteau's Conshelf experiments. It was, however, a " friendly competition ", during which both technical and logistical support were exchanged, so that representatives of both Jacques Cousteau and Edwin A. Link were present at Sealab I.
costs
Sealab I project cost US $ 148,000. When converted using the GDP deflator, this corresponds to an amount of US $ 886,000 in 2015.
Specifications
Sealab I consisted of converting two experimental floats for mine clearance. For reasons of symmetry and buoyancy , the tip of one object has been joined to the main part and the tip of the other to form a cylinder. This finally had a length of 12.19 m (40 feet) and a diameter of 2.74 m (9 feet), so a usable area of about 33 m². The thickness of the shell varied from 0.95 cm (3/8 ") in the top of the tip to 1.91 cm (3/4") in the bottom 120 degrees of the barrel.
The inner area was divided into two rooms: a living area, which was under a helium atmosphere, and the work area under constant influx of compressed air . The two rooms were connected by a gas-tight bulkhead . The air area should u. a. serve to simplify communication with the surface, because this way the voice distortion caused by the helium could be avoided.
The time allowed to decompress from a depth of 61 m (200 feet) was 30 hours. The temperature in the habitat was 28.9 ° C (84 ° F) while the humidity was maintained at 72%.
A speech unscrambler was used for communication in order to eliminate the distortion in the helium atmosphere.
Material was transported using an elevator system.
Supply ship YFNB-12
As a supply ship served Light yfNb-12, which was built in 1945 and modified several times. It was 82 m (268 feet) long and housed a deck decompression chamber , compressors, a control room, diesel generators, a submersible decompression chamber, and communication systems. It also had a crane and a winch, which made it ideal for the project. However, it was very susceptible to the effects of waves and thus proved to be inadequate to safely lower the habitat, so the Argus Island research platform anchored on the seabed was used for this purpose .
supply line
A supply line ( umbilical cord ) served as a connection to the surface , containing lines for fresh water, compressed air, helium and samples for atmospheric analysis, as well as cables for electricity, communication, TV, telephone, telex and telegraphy.
chronology
- May 20: Sealab is launched for the first tests
- May 22nd: The habitat is towed to the scene of action ( Stage II ) in front of Panama City in Florida
- May 23: First attempts to lower. Due to a misunderstanding, the habitat sinks uncontrollably to a depth of 18.3 m (60 feet) and runs about half full of water. Therefore she is lifted again and towed back.
- May 26th: The facility is launched one more time
- May 27: Successful lowering and test operation of 30 hours without a crew
- May 28: After successful tests, the habitat is recovered and towed ashore along with the supply ship
- June 6th: Start of transport to Bermuda
- June 12th: Arrival in Argus Island
- July 14th: Ballasting begins to descend to 3000 pounds of negative buoyancy . Water flows into the habitat through an improperly closed valve, which in turn leads to short circuits and various damage to habitat facilities. The mission is canceled and you return to the port.
- July 18: Another attempt at lowering, this time not from the supply ship, but from a permanently installed crane on the Argus Island research platform , with the help of which the habitat successfully touches down on the seabed at a depth of 50 m.
- July 19: Beginning of the 24-hour test phase without a crew
- July 20: The first crew is lowered by a pressure chamber. Beginning of the manned operation
- July 29: The operation is interrupted due to bad weather conditions. Begin recovery at an ascent rate of 0.3 m (1 foot) per 20 minutes. This operation went smoothly to a depth of 33.5 m (110 feet) when it was decided to pause due to heavy swell. The crew transfer to the submersible pressure chamber. After several hours the habitat can be recovered and Sealab is towed ashore.
- August 1st: The crew leaves the pressure chamber
- August 4th: Sealab I is officially ended with a press conference .
result
Sealab I was considered to have been successfully completed and demonstrated that ...
1. ... " Humans can better perform useful work at depths of more than 60 m by being firmly integrated into the underwater environment through a habitat, instead of short, costly advances and a return to surface pressure to meet their living needs " and
2. " No adverse physiological effects from exposure to the experimental conditions to the Aquanauts of the Sealab I project. "
Documented problems
- Due to a misunderstanding during the initial subsidence, the habitat first sinks to a depth of 3 m (10 feet). As the hatches on the underside were open, the increased pressure and the resulting compression of the air in the habitat caused water to flow into the interior. This increased the weight, which led to further sinking. The habitat eventually sank to a depth of 18.3 m (60 feet) and was half full of water. At the time, it had a negative buoyancy of 454 kg (1000 pounds). For future missions it was recommended to close the hatches when lowering, which would have led to a completely different pressure-resistant construction plan.
- During an outboard operation, Sanders W. Manning accidentally hit parts of the Sealab structure with his equipment , whereupon his gas control valve closed. After his oxygen was used up on the way back to the habitat, he passed out in the shark protection cage under the entrance. However, through the use of first aid measures, he was saved and had no other injuries other than profuse bleeding in his eye, so that he could continue his service.
- The Manning accident was u. a. attributed to the fact that after several problem-free days, the Aquanauts had a mentality of unconcern, leading to non-compliance with diving rules such as the buddy system (partner-wise diving), buddy-check (cross -checking of diving equipment by the partner) or failure to inform the surface center led. Following this accident, the original discipline was implemented again.
- When two aquanauts without MK VI devices entered the air-filled area, both suffered a sudden nitrogen anesthesia. In retrospect, this room was also flooded with the helium mixture in order to avoid further accidents of this kind.
- It turned out that structures the size of the Sealab I habitat are very difficult to lower from a ship, because every movement caused by waves and wind is transferred in parallel to the habitat to be lowered. The supply lighter was therefore abandoned and the permanently installed platform Argus Island was used .
- The diving suits, the material of which was compressed by the increased pressure and no longer relaxed as desired, turned out to be inadequate for the planned diving assignments.
- The hose connections (hookah) between the diver and the habitat did not work satisfactorily, so that a revision of the system was recommended for the following projects.
- The breathing gas mixture was maintained at 4% oxygen, 17% nitrogen and 79% helium. However, the aquanauts would have preferred a higher partial pressure of oxygen in order to achieve a higher level of well-being.
Sealab II
Sealab II took place approximately 1 km from the Scripps Institution of Oceanography pier in La Jolla , California at a depth of 62.5 m (205 feet) between August 28 and October 14, 1965 . It was as part of the Office of Naval Research (Office of Naval Research) Man-in-the-Sea series of deep diving system program ( Deep Submergence System Program ) conducted to explore the benefits of stations on the seabed.
During the missions, the Aquanauts made no- stop exits to depths of 81 m (266 feet) and 91 m (330 feet) respectively.
Like Sealab I , the atmosphere within the habitat consisted of a helium-oxygen-nitrogen mixture under ambient pressure.
Three teams each spent 15 days in the facility. The astronaut Scott Carpenter was the only one who lived in Sealab II for 30 days , during which he had a phone call with Gordon Cooper , who was in the Gemini capsule in Earth orbit.
Unlike Sealab I , which took place in the warm waters of Bermuda, it was much cooler in California. The water temperature at the surface was 21.11 ° C (70 ° F), beyond the thermocline at 18.3 m (60 feet) it dropped to 12.8 ° C (55 ° F) while the surrounding water was at depth 205 feet (62.5 m) was less than 48-50 ° F (10 ° C).
specification
The habitat consisted of a steel cylinder 3.66 m (12 feet) in diameter and 17.37 m (57 feet) long, giving it an area of approximately 63.57 m². It was this bar in a position to an internal pressure of about 8.75 (125 psig to withstand) and was in accordance with the ASME Pressure Vessel standards ( ASME boiler code for unfired pressure vessels constructed).
It contained eleven portholes with a diameter of 60 cm (2 feet) each and the same pressure resistance of 8.75 bar.
The habitat had three entrances: the bottom opening about four feet in diameter, an emergency exit about 27 inches in diameter at the other end of the habitat, and a surface entrance also about four feet in diameter about 69 cm (27 in) at the top in the center of the plant. The main access had an entry trunk approximately 8 feet in diameter and approximately 2.5 feet in depth. This apron should compensate for regular changes in the internal pressure as well as expected changes in the ambient pressure due to tidal changes and the associated water level. There was approximately 6 feet of free space under the habitat to allow free movement during entry and exit. The outside area of the main entrance was surrounded by a shark cage to protect divers from sharks . The reason for this was the fact that the aquanauts stepped out of the habitat with their feet first and thus could never be sure what was under their feet.
Sealab II had three internal and one external ballast tanks. The internal tanks filled the top volume of the habitat at full length and approximately 91 cm (3 feet) high. The external tank was located in the center above the habitat, about 8 feet (2,44 m) in diameter and 7 feet (2.13 m) tall, similar to a submarine command post Habitat. It had hatches on both its top and bottom and thus included the surface access already mentioned. On the surface, the tank therefore served as a breakwater for this access. The water ballast system generated the following buoyancy options:
- 26 t positive buoyancy during the towing process on the surface
- 7 t positive buoyancy on the surface (before sinking)
- 4 t negative buoyancy during descent / ascent
- 12 t negative buoyancy on the sea floor
A concrete deck within the habitat and weights on sleds under the habitat served as rigid ballast.
Since the platform on which the habitat was attached, sat leaning on a substrate, the plant received the humorous nickname The Tiltin 'Hilton (English for The crooked Hilton ).
Establishment of the habitat
All mechanical equipment was tested and certified for operation under high ambient pressure. Particular care was taken to ensure that they do not release any toxic substances into the environment. All cavities had either openings for pressure equalization or resistance to the effects of pressure in the habitat. Pressure gauges have been removed as they were only designed for high pressure in normal air. All devices have been tested under appropriate conditions that may include a. included high pressure, increased density, higher specific temperatures, and increased heat conduction. The facility had a toilet, three sinks, a water heater, an emergency tank for drinking water with a capacity of about 568 liters (150 gallons), two showers in the entrance area, two hookah compressors for supplying air to divers via hose from the habitat, and one Fridge-freezer combo with a volume of approximately 142 l (5 cubic feet) each.
Air conditioning
The preparation of the internal atmosphere included the following functions:
- Dehumidification with a capacity of approximately 68 liters (15 gallons) per day
- Air circulation of approximately 33,980 liters (1200 cfm) per minute
- Heating with an output of 25 kilovolt amperes
- Carbon dioxide filter ( scrubber ) with a capacity of about 500 grams per hour through about 75 liters (4600 cubic inches) of lithium hydroxide
- Carbon filter for removing hydrocarbons , odors and aerosols
- Systems for breathing gas analysis and mixing
Use of a trained dolphin
The Sealab II program was the first to use a dolphin named Tuffy to rescue aquanauts. Tuffy was equipped with a special harness and was trained to first come to the habitat following an acoustic signal. There he received a ring to which a rope was attached. The signal has now been turned off while a diver who had lost his way back to the habitat emitted a second signal. So Tuffy should bring the ring to the lost diver, who could find the way to the habitat through the rope.
(see also: United States Navy Marine Mammal Program )
Atmospheric impurities
Before the start of the project, it was assumed that the internal atmosphere would be contaminated. In particular, it was expected that high levels of hydrocarbons would be produced by cooking processes. As a preventive measure, a 25 kg (50 pound) charcoal filter was installed and it was found to be effective. In addition, all frying and deep-frying processes were prohibited.
Later in the mission, the aquanauts regularly complained of headaches. The reason was assumed to be high carbon monoxide concentrations. The following measurements gave values of 20 ppm . To reduce this, four canisters with lithium hydroxide to bind the carbon dioxide contained in the exhaled air were emptied and instead filled with hopcalite , which had already proven its worth in nuclear submarines. However, it was found that the concentration of carbon monoxide had already started to decrease several days before this measure. This decrease curve showed no noticeable change by the hopcalite, so it was concluded that the cause of the increase in carbon monoxide was inadvertently eliminated and unknown mechanisms led to a gradual decrease. In addition, the involvement of hopcalite in the binding of carbon monoxide has been questioned.
Ecological studies
The Sealab II Environmental Study attempted to grow barley and marigolds from seeds in the Sealab atmosphere . While the barley plants developed healthily, the seeds of the marigolds only produced a single seedling.
costs
The Sealab II program costing 1.4 million US $ and thus was almost ten times as expensive as Sealab I . When converted using the GDP deflator, this corresponds to an amount of US $ 8,230,000 in 2015.
result
The successfully completed Sealab II program confirmed Sealab I's knowledge that people can do useful work under high ambient pressures without harming their health. However, " human performance deterioration which increases with the complexity of the task " was also highlighted.
Sealab III
Upon completion of Sealab II , the habitat was modified to a depth of over 180 m (600 feet) and was named Sealab III . In February 1969 the habitat near San Clemente , California was lowered. While attempting to repair a helium leak, one of the four divers suffered a fatal accident due to the lack of soda lime, which led to all other US Navy programs being discontinued.
Facilities
The supply ship was the 62 m (203 foot) long rocket launcher Elk River, which had been specially modified for deep diving projects. It contained u. a. spacious deck decompression chambers (DDC) in which divers were compressed before transferring to personnel transfer capsules (PTC) that took them to the habitat. On the way back, these PTCs were coupled to the DDC, in which the divers were then decompressed. The PTCs were heated and were 8 feet in diameter.
Berry Cannon's fatal accident
Shortly after Sealab III dropped to the ocean floor on February 15, a leak was discovered in the habitat, releasing 85 m³ (3000 ft³) of breathable gas per hour that had to be pumped up from the surface. The reserves on board the Elk River would therefore be sufficient for about a day before the habitat would begin to fill up with water. Commander Jack Tomsky then decided to compress four divers of the first team to ambient pressure in three hours, five times faster than planned and recommended by medical advisors. These four were divers
- Robert Barth (38), sergeant
- Berry Cannon, 33, engineer
- Richard Blackburn (30)
- John Reaves, 37, photographer
Chronology of February 16
- 17:00 four aquanauts transfer to the personal transfer capsule (PTC)
- 17:25 the PTC is decoupled from the pressure chamber on deck and lifted into the water
- 18:15 the PTC reaches the seabed, 12 m (40 feet) of Sealab III removed
- 18:45 Barth and Cannon get out of the PTC and swim to the habitat
- 7:07 p.m. Cannon returns to the PTC complaining of extreme fatigue and cold as Barth tries to open the hatch to the habitat. However, due to a difference between the interior and ambient pressure, which a weight of 6 t exerts on the hatch and of which Barth has no knowledge, he does not succeed in doing this.
- 19:12 Barth reaches the PTC again
- 20:46 the PTC is raised and coupled to the pressure chamber on deck
Chronology of February 17th
- 02:00 It is decided that Barth and Cannon should be sent to the habitat one more time to close the leak, although Barth complained of pain and difficulty breathing on the first dive and both were tired from the cold and insomnia.
- 03:40 the PTC is decoupled from the pressure chamber on deck
- 04:13 the PTC is launched
- 04:33 the PTC reaches the habitat
- 05:08 Barth and Cannon open the hatch of the PTC and begin to exit
- Shortly thereafter, Cannon ran into problems. Barth tries to drag him into the small air space under the habitat hatch and give him his emergency regulator. Meanwhile, Cannon goes into convulsive convulsions. When all efforts are unsuccessful, Barth begins to drag Cannon back to the PTC, but has to take him off in the meantime because he has to turn back himself to free his tangled supply line. In doing so, he uses up his strength to such an extent that he can only return to the PTC on his own. Blackburn leaves the PTC to rescue Cannon, while Reaves tries to get Barth into the PTC.
- 5:15 am PTC reports to the surface that Cannon is in serious trouble. The PTC is closed and raised to the surface. At the time, Cannon is passed out and is no longer breathing.
- 06:05 the PTC is on board the Elk River and coupled to the pressure chamber. At this point, it is believed that Cannon is no longer alive.
- Investigations later reveal that Cannon died of carbon dioxide poisoning because the soda lime in one of the four Mark IX diving devices at the PTC was not refilled. None of the parties involved was held responsible.
_and_SEALAB_III_drawing_1968.jpg)
costs
The Sealab III program should cost 10 million US $ and so would be more than seven times as expensive as Sealab II and more than 67 as expensive as time Sealab I have been. When converted using the GDP deflator, this corresponds to an amount of more than US $ 50 million in 2015.
Criticism by Bill Bunton
Bill Bunton, who was designated as the Aquanaut for Team 4, later blamed several points for the failure. He criticized the fact that several experienced personalities had been exchanged for regular officers. George F. Bond was still a senior medical officer and principal investigator, but he was deprived of his previous competencies. In addition, divers with insufficient or no deep diving experience were selected as crew. The depth, which was three times that of Sealab II , also caused discomfort. The confirmed 610 feet (186 m) are simply " too deep, too early ". Forty-five divers would complete dozen of specialized tasks in the water during which they would be dependent on numerous private subcontractors. The project conjures up a disaster. Technology would rank higher than human control. A month before the start of the program, valves are clogged, lines and equipment are defective. An aquanaut almost drowned in the pool during a training dive. The personnel transfer capsule (PTC) fell into water with the hatch open, deliveries were delayed, the habitat was flooded, cables were incorrectly wound on their drums. The PTC ran after a test at 168 m (550 feet) full of water, repairs were delayed, test procedures and deliveries of new equipment were repeatedly delayed. For these reasons, Lieutenant Laurence Bussey, originally intended to be the photographer for the first team, left hastily the day before the mission began. Shortly before the program started, Scott Carpenter threatened to leave and only stayed out of loyalty to the other divers.
Sealab III as classified by the US Navy
John Craven, a former U.S. Navy scientist and director of a Sealab secret program , told the Associated Press in 2002 :
SeaLab III's true purpose was to test a system that would allow divers to exit a submarine, walk on the sea floor and retrieve objects. To that end, it succeeded. The notion that SeaLab had failed turned out to be a perfect cover to establish a major program of submarine intelligence using that technology. To do that, we couldn't announce to people that SeaLab was successful.
The real intent of Sealab III was to test a system that would allow divers to disembark from submarines, move around the sea floor, and recover objects. In this regard Sealab III was a success. The assessment that Sealab III had failed turned out to be the perfect cover for starting an undersea espionage program using technology (from Sealab). To this end, we could not finally announce that Sealab had been a success.
The use of the submersible USS Halibut , for example , in which Soviet test missiles were secretly recovered in the Sea of Okhotsk and a communication cable laid under water was tapped, was based on the relevant findings of the Sealab program.
Web links
- Information on Argus Island on SOFAR Bermuda
Individual evidence
- ↑ a b Sealab I Project Group: Project Sealab Summary Report: An Experimental Eleven-Day Undersea Saturation Dive at 193 Feet . ONR Report ACR-108. Office of Naval Research. Dep. of the Navy, Washington, DC June 14, 1965.
- ↑ a b c d e f Bill Bunton and Mary Heglar: San Diego Magazine: "Death of an Aquanaut", excerpt from "Target: The Awa Maru". June 29, 2007, accessed December 21, 2016 .
- ↑ MeasuringWorth.com: Compute the Relative Value of 148,000 US Dollars 1964-2015. (No longer available online.) Archived from the original on October 17, 2017 ; accessed on December 21, 2016 (English). Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ a b c d e f D.C. Pauli & GF Clapper: Project Sealab Report: An Experimental 45-Day Undersea Saturation Dive at 205 Feet . Ed .: Office of Naval Research, Department of the Navy. ONR Report ACR-124. Washington, DC March 8, 1967.
- ^ Office of Naval Research: Sealab. Archived from the original on April 10, 2015 ; accessed on December 27, 2016 (English).
- ↑ a b Seth Hettena: Midland Daily News: New Light Emerges About Navy's Sealab. March 27, 2002, accessed January 5, 2017 .
- ^ MeasuringWorth.com: Compute the Relative Value of 1,400,000 US Dollars 1965-2015. (No longer available online.) Archived from the original on July 31, 2017 ; accessed on December 21, 2016 (English). Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ USNUM Curator: United States Naval Undersea Museum: Sealab II End Bell. September 19, 2016, accessed December 21, 2016 .
- ↑ MeasuringWorth.com: Compute the Relative Value of 10,000,000 US Dollars 1969-2015. (No longer available online.) Archived from the original on July 31, 2017 ; accessed on December 21, 2016 (English). Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
