Houston's Manned Spacecraft Center and at KSC in Florida. Once these were available for use, the crew had difficulty finding enough time to do everything, even with the help of the backup and support crews; the crew often worked 12 or 14 hours per day. After the CM was completed and shipped to KSC, the focus of the crew's training shifted to Florida, though they went to Houston for planning and technical meetings. Rather than return to their Houston homes for the weekend, they often had to remain at KSC in order to participate in training or spacecraft testing. According to former astronaut Tom Jones in a 2018 article, Schirra, "with indisputable evidence of the risks his crew would be taking, now had immense leverage with management at NASA and North American, and he used it. In conference rooms or on the spacecraft assembly line, Schirra got his way." The Apollo 7 crew spent five hours in training for every hour they could expect to remain aboard if the mission went its full eleven days. In addition, they attended technical briefings and pilots' meetings, and studied on their own. They undertook launch pad evacuation training, water egress training to exit the vehicle after splashdown, and learned to use firefighting equipment. They trained on the Apollo Guidance Computer at MIT. Each crew member spent 160 hours in CM simulations, in some of which Mission Control in Houston participated live. The "plugs out" test—the test that had killed the Apollo1 crew—was conducted with the prime crew in the spacecraft, but with the hatch open. One reason the Apollo1 crew had died was because it was impossible to open the inward-opening hatch before the fire raced through the cabin; this was changed for Apollo7. Command modules similar to that used on Apollo7 were subjected to tests in the run-up to the mission. A three-astronaut crew (Joseph P. Kerwin, Vance D. Brand and Joe H. Engle) was inside a CM that was placed in a vacuum chamber at the Manned Spaceflight Center in Houston for eight days in June 1968 to test spacecraft systems. Another crew (James Lovell, Stuart Roosa and Charles M. Duke) spent 48 hours at sea aboard a CM lowered into the Gulf of Mexico from a naval vessel in April 1968, to test how systems would respond to seawater. Further tests were conducted the following month in a tank at