On 2 July, Senator Proxmire voiced another objection to the joint flight. He made public the testimony of a top Central Intelligence Agency official who raised questions about the ability of the Soviets to control two space shots at one time - ASTP and Soyuz 18/Salyut 4, which had been  launched on 24 May 1975. Proxmire had part of Carl Ducket's testimony declassified so he could release it to the press. The Senator's news release read in part:
During hearings before the HUD and Independent Agencies Subcommittee on June 4, the CIA Deputy Director for Science and Technology, Carl Ducket, stated, "I do not think they (the USSR) are in good shape to handle two missions at once from the command point of view."
. . .
"This warning from the nation's top scientific intelligence expert should not be taken lightly," the Senator said.
The Soviet Union has announced that the two Russian cosmonauts already in space in the Salyut space lab will not be brought back to Earth before the July 15th launch of the joint US-USSR space mission.
In view of the potential hazards that already exist during the joint mission, the added complexity of having two space missions going at once should be avoided at all costs.
Soviet communications capabilities and central management facilities are greatly inferior to those of the U.S. Having two missions in space at once, including one involving two spacecraft of different nations, is complex enough to warrant concern that the ASTP mission may not get the full support it needs to be successful.
Particularly troublesome is the potential for inadequate command and control should one or the other mission encounter difficulty.53
Proxmire urged NASA to postpone the ASTP launch until the Soviets brought Soyuz 18 home. He said that it would be "a simple matter to de-orbit the two cosmonauts. . . . Then the joint mission could proceed without concern over this particular problem."54 Administrator Fletcher responded on 3 July to Proxmire's request to postpone the launch.55 "Although the Soviets have not made any official announcements with respect to their plans for the Salyut mission," Fletcher told the Senator, the Soviet press on 27 June had quoted Leonov as saying that the Salyut mission would continue during ASTP. Since the final full-scale simulation for ASTP had involved the two countries' control centers, Glynn Lunney had used that occasion to discuss the multiple flight control matter with Bushuyev.
The Professor indicated that there had been no final decision on the length of the Soyuz 18/Salyut 4 mission.56 During their conversation, Bushuyev assured Lunney that should the two missions overlap, the Soviets would use two separate ground control teams and control centers for the two missions. ASTP would be directed from the center at Kaliningrad, while Soyuz 18/Salyut 4 would be conducted by the center that had been used prior to Soyuz 12. The Professor also told his American counterpart that the  ASTP mission had been assigned priority if the two sets of space vehicles should pass simultaneously within the same zone of coverage of a U.S.S.R. tracking station. This, of course, would be highly unlikely because ASTP and Salyut had distinctly separate flight paths. In fact, NASA's tracking specialists had made independent calculations that indicated that the two Soviet missions would be in communication with the same U.S.S.R. ground station only twice during the ASTP flight and then only for intervals of about 0.5 and 1.5 minutes. Administrator Fletcher told Proxmire that based upon the data available and the nature of the two missions, "NASA has concluded that the Soyuz 18/Salyut 4 mission does not constitute a hazard to ASTP and that there is no reason to delay the launch of ASTP if the Salyut mission is still in operation."57
Senator Proxmire, however, would not let the issue die. After inserting anti-ASTP articles in the Congressional Record on 11 July, he leveled another blast at the joint flight on the 14th, the eve of the launch.58 Citing CIA data, the Wisconsin senator noted that:
the Soviets have encountered severe problems in space and their technology is inferior to that of the U.S. in almost every category.
- the Soyuz rendezvous and docking system has failed almost half the time
- the current level of Soviet preparation still is below that of the US
- the threat of a minor fire poses a moderate risk to the ASTP while a major fire is much less likely
- Soviet communications are not up to the quality of US communications
- Cosmonaut training and ground control crew proficiency are inferior to that of US counterparts.
- There has been some technology flow to the Soviet Union as a result of the ASTP. Future joint missions would pose more of a potential for technology drain
- the primary advantage to the USSR from the ASTP has been in observing US management and program operational techniques
- the Soviet lunar program has produced a string of failures.
In summary, the US has a significant technological lead over the USSR in the following areas: communications, management and quality control, handling of emergency situations, launch coordination and procedures, computerized functions, capability for inflight mission changes, space medicine, and crew training.59
Looking back on the Senator's remarks, American ASTP Commander Tom Stafford said that this was the first time that Proxmire had been worried about aerospace safety. Stafford had seen the Soviet flight hardware and had worked with the Soviet crews. And he was ready to fly. Stafford believed that Proxmire was simply opposed to space flight in general.  Whatever the sources of his concern, NASA did not share them. Nearly everyone was ready for the launch, and the space agency personnel had said so at the Headquarters Flight Readiness Review on 12 June.60
53. News release, issued by the office of Senator William Proxmire, Wisconsin, 2 July 1975.
55. Proxmire to Fletcher, 2 July 1975.
56. Fletcher to Proxmire, 3 July 1975.
57. Ibid.; and Thomas O'Toole, "U.S.-Soviet Flight Delay Is Rejected," Washington Post, 3 July 1975.
58. "Apollo-Soyuz Flight," Congressional Record, 11 July, S12417. Proxmire inserted Thomas O'Toole, "Apollo-Soyuz: Another Wheat Deal," Washington Post, 11 July 1975, and Tom Braden, "The Space Link-Up," Washington Post, 5 July 1975.
59. News release, issued by the office of Senator William Proxmire, Wisconsin, 14 July 1975.
60. Interview, Thomas P.
Stafford-Ezell, 6 Apr. 1976.