Neutral Buoyancy Simulator - Second Tank

Second Tank

After the utility of the technique had been demonstrated, in January 1966, workers repurposed a larger explosive forming tank for neutral buoyancy testing. The larger pool was 25 feet (7.6 m) diameter, 15 feet (4.6 m) deep. A 10 feet (3.0 m) tall 35 feet (11 m) diameter damaged Saturn V corrugated section with a conical roof atop enclosed the now-heated facility with adequate lighting and more room for larger hardware than the initial tank.

The budget for the second tank was especially tight. It included a swimming pool filter from Sears and a tap into an adjacent steam line for water heat. Algae engaged chemists for nearly a year to find an appropriate balance of chemicals for the unique arrangement.

Initial tests again focused on S-IVB workshop: airlock ingress and egress, and S-IVB hatch cover removal.

The second tank saw astronaut training in pressure suits beginning with the Navy Mark IV. The MSFC Manufacturing Engineering (ME) lab developed a constant pressure valve which "made it possible to maintain neutral buoyancy at any depth." Divers first tried the Mark IV in the tank in July 1966, and Alan Bean spent two hours "executing typical astronaut activities" in the tank on September 6, 1966. Bean was "quite enthusiastic and outspoken about neutral buoyancy as one of the mandatory methods of simulation for all the S-IVB Workshop experiments," according to Manufacturing Engineering director W. R. Kuers. Stocks, the controller for that exercise, reported Bean's dive began with a leaky glove followed by his Mark IV suit tearing under the arm and requiring diver-assisted evacuation. Bean proceeded with exercises in regular scuba gear.

By early 1967, the schedule for the simulator was full. Though Alan Bean had visited and consulted on the project, the intent of the simulator was not astronaut training but to verify that "the MSFC developed hardware is safe, simple to handle, accessible, and trouble-free," wrote F. Belew in his March 13 report to von Braun. Focus at this time was largely on early development of procedures for the Apollo Applications Program. Due in large part to Bean's enthusiasm for the project, the Manned Spacecraft Center coordinated with MSFC to provide two astronauts on an as-needed basis, medical support, crew quarters, and safety consultations for simulations.

In the same report, Belew said that people found it necessary to use both hands for most tasks - one to do the work and the other to provide leverage for the work. He also outlined plans for a third tank to be installed in building 4706.