Apollo 15

This is Apollo Control at 198 hours, 37 minutes. We should be acquiring Endeavour shortly on its 62nd revolution of the Moon. We'll stand by live during this pass.

This is Apollo Control at 198 hours, 52 minutes. There will be a change of shift briefing at the end of this shift. It will begin in a few minutes after Loss Of Signal on this revolution. Stand by please.

This is Apollo Control. That - that change of shift briefing should start in approximately an hour, approximately 4:30. We'll continue to stand by live in this pass. The crew busy with orbital science. We're showing cabin temperature in Endeavour of 75 degrees Fahrenheit [23.9°C], cabin pressure of 4.8 pounds per square inch [33.1 kPa].

This is Apollo Control at 199 hours. The Flight Dynamics staff has computed the final update on the LM impact point. The coordinates are 26.362 degrees north latitude, and .253 degrees east longitude. The final aim point was 26.2 degrees north and 1.1 degrees east. The impact point represents about a 13 [nautical] mile [24.1 km] down track miss from the aim point. The impact time, final update on that was 181 hours, 29 minutes, 36.24 seconds.

This is Apollo Control. The suit integrity check, being discussed with Dave Scott, was one that was performed last night prior to jettisoning of the Lunar Module. This check is a routine check of the suit loop, generally performed by pumping the suits up to about 9 pounds per square inch of pressure or perhaps a little bit more and then monitoring the decay rate and also the oxygen flow rates to the suits. On, I believe it was about 2 occasions, Scott reported, and we were able to monitor on the ground, a high flow rate, indicating that a good pressure integrity was not being maintained. After making some adjustments to the suit and particularly after inserting some auxiliary plugs in the fittings which normally, while the suits are being worn in the Lunar Module or on the lunar surface, would have water hose connections to the back packs, but which are connected to nothing when used in the Command Module. The plugs were inserted inside the suits and the subsequent pressure integrity check showed the suits to be good. Throughout the day, we've been working on the problem here on the ground to attempt to understand what had happened and the conversation with Scott was to attempt to gain some additional information. As you heard, both the ground analysis and Dave Scott's analysis is that we do have, at the present, time a good suit circuit - good suit integrity checks, and that the suits and the suit circuits are maintaining pressure as they should. And the implication from the conversations is that a most likely suspect is some dirt in some of the fittings. In Mission Control at the present time, we're completing a shift handover, Flight Director Glynn Lunney and his team of flight controllers will be replacing Gerry Griffin and his team. The spacecraft communicator on this shift is Astronaut Bob Parker.

We have about 30 seconds now until loss of radio contact with Endeavour. Spacecraft completing its 62nd revolution of the Moon and we'll be reacquiring in a little over 45 minutes. There will be a change-of-shift press briefing probably in about five minutes in the MSC News Center. The participants in the briefing will be Flight Director Gerry Griffin, and spacecraft communicator Joe Allen. At 199 hours, 51 minutes; this is Apollo Control.

This is Apollo Control at 200 hours, 35 minutes and we're about 1 minute away from regaining radio contact with Apollo 15. Spacecraft now in it's 63rd revolution of the Moon. While the spacecraft has been behind the Moon, Flight Director Glynn Lunney has completed a status review with his flight controllers. Everything appears to be progressing smoothly at this point. And the Flight Activities Officer [FAO] reports that we should be pretty much back on the normal Flight Plan by the scheduled time for the crew to begin their rest period tonight, which would be at 203 hours, 40 minutes, or a little over 3 hours from now. And leading up to that time, well we'll primarily be completing the configuration of experiments in the SIM bay, getting the spacecraft squared away and ready for the sleep period. We should have acquisition - we do have Acquisition Of Signal now. We'll stand by for a call to the crew.

The ultraviolet photography, which the crew is preparing to perform in about 2 minutes, is done with the Hasselblad electric camera, mounted on a special window bracket. The purpose of the experiment is to obtain ultraviolet photographs of the Earth and the Moon, and these will be used in a study of planetary atmospheres. They'll also be used for investigation of short wavelength radiation from the lunar surface.

Al Worden's last comments referred to the Mass Spectrometer boom. He reported that it required about seven or eight cycles to get the - of the switch to get the boom to retract fully from it's extended position. That boom extends out about 24 feet [7.3 metres] from the Service Module. And we have previously noticed some problems in retracting the boom. It appears that these problems, usually a slow or a balky retract, occur when the retraction is attempted in darkness leading to the suspicion that perhaps a cable is stiffening up and causing the thing to be balky to retract. We don't appear to have the problem when it is retracted in full sunlight. This last retraction attempt was done at sunrise, which would go along with the theory. At that point, it would still be cold, would not have had a chance to warm up from direct exposure to the Sun. The instrument itself is continuing to function very well - the Mass Spectrometer - and we're getting very good data from it; the problem being in the - in the boom mechanism that extends and retracts it. And, insofar as possible, we will attempt to do the retractions while the boom is in sunlight.

This is Apollo Control. The crew has now completed the photography of the terminator using the electric Hasselblad camera and also the Mapping Camera in the Scientific Instrument Module bay. We're standing by now for them to begin a procedure which we hope will possibly solve the problem with the Laser Altimeter. About 35 or 40 minutes ago, we asked the crew to...

What Al Worden is doing is cycling the switch on the Laser Altimeter on and then off. And it'll do this 20 times. The hope is that in cycling the switch it will cause a particular circuit in the laser altimeter to fail. This circuit is used to discharge high voltage from some of the components and in discharging the voltage, it's thought that perhaps we're introducing some noise into the altimeter which is in turn causing the intermittent flow of data from that particular instrument.

Al Worden has completed cycling the switch on the Laser Altimeter; and the Orbital Science Officer reports, from the telemetry, it appears that the procedure did no good, that the Laser Altimeter is still not functioning properly.

This is Apollo Control. We're now about 1 minute, 15 seconds from losing radio contact with Endeavour. On the next revolution, the crew will be eating and then we plan to put them to bed.

And we've had Loss Of Signal now. We'll hear from the crew again in about 45 minutes. At that time, they'll be at the beginning of their 64th revolution of the Moon. At the present time, the spacecraft is in an orbit 66.8 by 51.8 nautical miles [123.7 by 95.9 km]. At 201 hours, 49 minutes; this is Apollo Control.

This is Apollo Control. We'll be back in radio contact with Endeavour in about one minute. The spacecraft now on its 64th revolution of the Moon and the orbit at the present time is 66.8 by 51.8 nautical miles [123.7 by 95.9 km]. On this pass, the principal activity will be to get everything set for the crew to begin their rest period. They have an eat period scheduled and we'll be getting the regular pre-sleep status report from them. We do have an update on the numbers for the total sample collected on the lunar surface. The gross weight of the samples - the weight of the rocks and soil plus the containers - is 226 pounds [102.5 kilogram] and our best estimate at the present time as to the net weight of the samples alone is 175 to 180 pounds [79 to 82 kilograms]. INCO says we have Acquisition of Signal now on the spacecraft.

This is Apollo Control. We've had Loss of Signal now with the spacecraft. Just before going around the corner, Dave Scott reported that they had, again, the problem that they'd experienced earlier in the flight, and had very quickly gotten it under control. That was a water leakage, coming from a diaphragm in the Lower Equipment Bay where the crew inject chlorine into their potable water system to maintain the purity of that system and the water there. And what, apparently, is happening is that a nut is working its way loose and allowing water to seep out from around the diaphragm, and the procedure to prevent the leak - or to stop it - is simply to take a Allen head wrench that the crewmen have onboard, and tighten the nut down. And Scott reported they had done this. We would not expect to have any further conversations with the crew. They're now or will shortly be in their rest period. We'll be reacquiring in about 45 minutes. Prior to beginning the rest period, we received a crew status report. Scott reported that they'd all been eating their meals as scheduled and have been consuming plenty of water. And he said that everyone is in fine shape and ready for the EVA. At 203 hours, 47 minutes; this is Apollo Control, Houston.