After Low returned to Washington, Administrator Fletcher reported on ASTP flight readiness to President Gerald R. Ford, a leading supporter of the project, and to Senator Proxmire, the major critic. Fletcher's letter to the President was short and cordial. He noted that ASTP was on schedule and expressed his hope that Ford would take an active part in the last Apollo launch. "We believe your personal involvement would further demonstrate this country's commitment to increasing cooperation with other nations."
 Should his schedule preclude attendance at the Apollo launch, Fletcher suggested that the President might want to speak with the crews during the joint phase of the mission.33
In writing to Senator Proxmire, Fletcher forwarded him a full explanation on the Soviets' 5 April Soyuz launch failure. During the course of the May meeting in Moscow, Glynn Lunney and Robert O. Aller, Chet Lee's Deputy, had been given a detailed briefing by Professor Bushuyev on the Soyuz launch abort. Since Proxmire had expressed a desire to be kept informed of all developments possibly affecting the safety of ASTP, Fletcher enclosed a summary of the findings. He told the Senator that NASA had reviewed all the Soviet data in detail and had concluded that the failure would not affect the safety of the Apollo crew.
Professor Bushuyev had told the Americans that several minutes after lift-off, when the central sustainer core of the launch vehicle was supposed to separate from the third stage, a sequencer relay failed and permitted some pyrotechnic latches to fire prematurely. This disabled three other pyrobolts and prevented the complete release of the sustainer core. Since the third-stage engine had been ignited, the pyro failure caused the vehicle to stray from its path. The abort sequence was automatically initiated when the spacecraft reached a 10-degree deviation from the programmed flight path. In quick succession, the third stage engines were shut down, the spacecraft was separated from the lower stage, and the retrorockets were employed to ensure the proper trajectory for landing. At the time of the abort, Soyuz had reached an altitude of 180 kilometers, traveling at about 5.5 kilometers per second. Lazarev and Makarov - veterans of Soyuz 12 - experienced g forces equivalent to nearly 14 times those on earth as they descended. Their landing site was 1,800 kilometers downrange from the launch pad, covered with waist-deep snow.
In his briefing to Lunney and Aller, Bushuyev noted that there were two basic differences in the launch vehicle that failed and the ones assigned to ASTP. A new type of relay was being used, and the pyro lock circuitry had been changed to prevent a premature firing of the explosive bolts. These modifications, which made the asymmetric separation as experienced in the 5 April flight impossible, had been included in a series of launch vehicles prior to the failure. That updated group of boosters had been flown ten times, including the two unmanned ASTP precursor missions and Soyuz 16. NASA was convinced that the aborted April launch did not pose a hazard to the American crew of Apollo-Soyuz. Furthermore, the agency was satisfied that this type of failure would not occur on 15 July. But should something prevent the successful launch of the prime Soyuz, the Soviets would have a second launch vehicle, spacecraft, and crew ready to count down. Despite  Senator Proxmire's concerns, the people at NASA expected to meet the Soviets in orbit.34
33. James C. Fletcher to Gerald R. Ford, 29 May 1975.
34. Fletcher to William
Proxmire, 4 June 1975, with enclosure, "Soyuz Launch Abort of April
5, 1975," 4 pp.; and Chester M. Lee, memo for record, "Information
Regarding Soyuz 18," 18 Apr. 1975.