Experiment Operations During Apollo EVAs

Experiment: Miscellaneous Tools and UHT Equipment

includes: Erectable S-Band Antenna, Modularized Equipment Transporter, TV stand, Flag, Universal Handling Tool, Dome Removal Tool, Fuel Transfer Tool, Radioisotope Thermal Generator, Lunar Equipment Conveyor
Acronym: MET, UHT, DRT, FTT, RTG, LEC


The MET was loaded with equipment used during the geology traverse of the second EVA. The CDR works with the core tube and extension handle. The ribbon cable of the LPM is visible to the rear of the MET.(AS-14-68-9404)

The erectable antenna as deployed at the Apollo 14 site. The open MESA is visible on the LM (AS-14-66-9256). The U. S. Flag is visible behind the dish of the antenna. See another view of the flag.

The RTG as deployed for the Apollo 14 ALSEP. The central station is visible in the background (AS-14-679366).

The fuel cask is visible in the upper right portion of this photo after it has been tilted away from the Apollo 12 LM and emptied of its fuel element for the RTG. The FTT and DRT (still attached to the fuel cask dome) are visible on the surface (AS-12-48-7034). See also the fuel cask on the Apollo 16 LM.

PI/Engineer: several
Other Contacts: several

Apollo Flight Nos.: all
Apollo Exp't No. NA

Discipline: general equipment

Weight: variable
Dimensions: variable

Manufacturer: RTG - Atomic Energy Commision; tools - JSC

Description/Purpose:
The Modular Equipment Transporter (MET) was a 2 wheeled, rickshaw type vehicle with pneumatic tires which was used to carry instruments, geological tools, and photographic equipment. It was only used on A-14. It was stored under the MESA in Quad IV. Its mass was 13.6 kg and it was capable of carrying up to 160 kg, but its actual load was much lighter. The crew released the MET by pulling the upper pip-pins and allowing it and the thermal blanket to fall to the surface. The low temperature limit (-56deg C) to which the tires were designed required the use of a special synthetic rubber for both the tires and tubes. The tires inflated as expected, and the MET was loaded with equipment without difficulty. They reported that it performed very satisfactorily. It was more stable than had been expected and could traverse the surface over a range of speeds without loss of control. The tires were smooth and did not kick up much dust. No appreciable soil adhesion was noticed on the tires or other structural components. The only difficulty encountered in pulling the MET was while attempting to climb relatively steep grades. Near cone crater it was easier for both astronauts to carry the MET than for one of them to pull it uphill alone. As it rolled on a level surface or downhill at relatively high speeds, the MET bounced; however, bouncing on the Moon was less than that observed on Earth in lunar-g simulations. Besides carrying more equipment than could be carried by hand, it served as a mobile workbench. Since constant gripping of the handle against the suit pressure would have tired the hand and arm of the crewmen, the handle was designed to permit control of the MET without requiring constant gripping. A triangular shape was used. The base of the triangle was long enough for insertion of the hand but the dimension perpendicular to the base was shorter than the width of the hand. Rotation of the hand toward the shorter dimension applied sufficient pressure for pulling and rotational control.

The erectable S-Band antenna used on A-12-14 was replaced with the antenna on the LRV for the J-class missions. It was also mentioned in the A-11 Lunar Surface Operations Plan for the alternate timeline, but was not emplaced. It was required only if the 210 foot dishes at Goldstone or Parkes (Australia) were not available. The larger antenna allowed better reception and color television. It was stored in Quad I. The A-12 Lunar Surface Operation Plan has 4 pages of activities on the timeline for the CDR. The A-12 crew commented that it was easy to deploy on its tripod but difficult to align. The entire unit tended to move about when the hand crank was used. The alignment sight did not have a sufficient field of view and had to be precisely aligned to contain the Earth's image. One man deployment was satisfactory, but two were needed for alignment. On A-14, the antenna was easily offloaded and presented no problems in deployment except that the netting which formed the dish caught on the feed horn and had to be released manually. The antenna obstructed the work area immediately around the MESA - a longer cable would have allowed deployment at a greater distance from the LM. They agreed that erecting it was a one-man job, but aligning required two. The timeline allowed 17 to 19 minutes for the entire task (depending on the mission), with coordination of two crew members on the alignment. Once set-up, the LMP re-entered the LM and moved the antenna switch on the comm. panel to "lunar stay" and monitored the signal meter. He also turned the LM steerable antenna track mode switch "off."

The fully unstowed PLSS antenna physically interfered with the S-band antenna reflector during alignment operations.

The maximum stable downward pitch of the reflector was 60deg. The tripod design limit to terrain slope which could be compensated for by manual adjustment was 5deg. Detailed procedures exist in the Lunar Surface Operations Plans and the Lunar Surface Procedures Documents.

On A-11, the TV system presented no major difficulty except that the cord was continually in the way. At first, the white cord showed up well, but it soon became covered with dust and was therefore difficult to see. The cable had a "set" from being coiled around the reel, and would not lie completely flat. Even when it was flat, however, a foot could still slide under it, and the CDR became entangled several times. The A-14 crew actually pulled the TV camera over one time after tripping on the cable. A TV tripod flew on many, if not all, the Apollo missions. On A-14 & 15 it was stored in the MESA.

The Radioisotope Thermal Generator (RTG) provided power to the ALSEPs and is discussed more under the ALSEP - general section. It was 19.6 kg, 40.6 cm in diameter and 46.0 cm long. The fuel element needed to be placed into the RTG from a fuel cask on the outside of the LM descent stage, where it was stored during flight. This cask rotated to point slightly downward to allow this operation upon pulling a lanyard. The DRT and FTT were used only for opening the fuel cask and transferring the fuel element to the RTG, respectively. Both were then discarded. The DRT had a temperature label on its shaft. The FTT had an engage/disengage knob and a temperature label on its shaft.

On A-12 the fuel element for the RTG would not come out of its cask easily and several minutes were spent working with the delicate element before it was removed satisfactorily. They had to hit the cask with a hammer while pulling on the element to coax it out. The A-17 crew had trouble removing the dome from the fuel cask. The chisel end of the geological hammer was used to pry the dome off the cask. The remainder of the operation went nominally.

Initial power output for A-12 on the lunar surface was 74 W (66.5 W after 4 years), for A-14 was 73 W (68 W after 3 years), for A-15 was 75 W (69.4 W after 3 years), for A-16 was 70.9 W (69.5 W after 2 years), and for A-17 was 77.5 W (76.9 W after 1 year.) The actual rate of decrease in output (primarily the result of changes in the lead telluride material from time, temperature, and pressure) for all five flight RTGs was considerably less than calculated predictions (~ one fourth the design specification rate.)

The U. S. Flag was implanted at all Apollo sites. The flag kit, lunar surface, which had a mass of 1.2 kg for A-17 (not to be confused with a flag kit, standard, that was carried to the surface and returned, which carried small flags for public relations purposes), was unstowed from the MESA, positioned at "1:30" relative to the front of the LM and ~6 meters from it. The lower staff was hammered into the soil, the upper portion was unfolded and then placed on the lower portion. Six to seven minutes were required for one crewman.

The Universal Handling Tool (UHT) was a general purpose device similar to an elongated Allen wrench. Two were included on ALSEP subpackage 2. The insertion end of the UHT was designed to fit both the carry sockets on the ALSEP instruments and structural units and the Boyd bolt fasteners. The head was equipped with a spring-loaded ball lock for positive retention in the carry sockets. A trigger at the handle end was used to release the lock. There were two temperature labels on the handle. The UHT was used to 1) handle and position the ALSEP units, 2) Transport and emplace experiment subsystems, 3) release Boyd bolt fasteners, 4) remove pull-pins and release Deutch fasteners, and 5) actuate the auxiliary "astronaut" switches on the central station.

The Lunar Equipment Conveyor (LEC) was a device which the crew used during EVA to transfer equipment to or from the ascent stage. It could also be used as a safety tether when going down the ladder or as an aid in ascending the ladder. Initially, a pulley-like double strap conveyor was used to raise and lower equipment. It was a thin, 60 foot continuous loop of 1 inch wide strap which looped through a support in the ascent stage and back to the man on the surface. The end of the loop was closed by two hooks, attached together, which provided a way to secure equipment to the LEC for transfer. The person on the surface could transfer items to the ascent stage by pulling the top strap which caused equipment hooked to the lower strap to go into the ascent stage. Although the concept was simple, the actual operation required significant time and effort - more if caution was not observed in keeping the straps untangled or if the proper procedures were not used. Up to five minutes plus a rest period was required. The A-11 crew found that, when the strap became coated with dust, the dust fell on the suit of the surface crew member and was also deposited in the LM cabin. The dust ultimately seemed to bind the pulley so that considerable force was required to operate it. A one-strap conveyor was used for A-12, but the crew reported that this also collected dust and deposited it in the cabin. In lieu of a conveyor, the A-14 crew reported that stability and mobility on the ladder, maintained by using one hand for support, was adequate to allow carrying equipment up the ladder. The A-15 crew agreed, and suggested a wrist strap attached to the item be used to leave both hands free while climbing the ladder. On A-16 and 17, sample bags and other items were easily hand-carried up the ladder, alleviating the dust problem. The conveyor was modified to a single short strap which retained the equipment transfer bag and was easily hoisted by one hand.

Unloading from the LM:
The UHT, FTT, and DRT were part of the ALSEP package and were removed with the two subpallets.

Transporting by foot or MET:
None of this equipment was placed on the MET. Carrying the S-band antenna was not a problem.

Loading/unloading tools/exp'ts on LRV: There was a tool carrier on the back of the LRV.

Site selection:
The RTG had to be 3 to 4 m from and +/- 20deg east of the central station to minimize the thermal load on it. A level site was desired for thermal view factors.

Deploying experiment: NA

Check-out of experiment: NA

Operation of experiment: NA

Repairs to experiment: NA

Recovery/take-down of experiment: NA

Stowing experiment for return: NA

Loading/unloading samples on LRV: NA

Loading of exp't/samples into the LM: NA

Stowing of package once in the LM: NA

Sampling operations - soil, rocks: NA

Trenching: NA

Raking: NA

Drilling: NA

Coring: NA

Navigating/recognizing landmarks:
The A-14 crew was never far enough from the LM, even with the aid of the MET, to be concerned about return to it. Their maximum distance was 1.4 km. At worst, they could follow its tracks back.

Were there any hazards in the experiment?
i.e. hazardous materials (explosive, radioactive, toxic), sharp objects, high voltages, massive, bulky, tripping hazards, temperatures?
All the ALSEPS had SNAP-27 RTG's to generate power. The fuel capsules for these were kept in a separate cask for safety (they were at 500deg C and radioactive) until the astronaut on the surface removed it and placed it into the thermocouple assembly with the FTT. The cask was mounted outside the descent stage of the LM. The A-12 crew commented that the fuel cask guard was not needed and commented that heat radiating from the fuel element was noticeable through the gloves and during the walk to the deployment site, but was never objectionable.

Was lighting a problem? NA

Were the results visible to the crew? NA

Would you recommend any design changes? No comments by crew.

Were any special tools required? NA

Was the orientation of the experiment (i.e. horizontal/vertical) important? Difficult?
The RTG was to be deployed on a horizontal (+/- 10deg) site, but no provisions were provided to level it.

Was the experiment successful? NA

Were there related experiments on other flights? NA

Where was it stored during flight? NA

Were there any problems photographing the experiment? No.

What pre-launch and cruise req'ts were there?
power, thermal, late access, early recovery?

What was different between training and actual EVA? No comments by crew.

What problems were due to the suit rather than the experiment? No comments by crew.

Any experiences inside the LM of interest from the experiment/operations viewpoint?
When the hot-fire tests of the RCS on A-14 were performed before lift-off, the erectable S-band antenna blew over.

References:

Final Apollo 12 Lunar Surface Operations Plan, JSC, October 23, 1969.

Apollo 14 Final Lunar Surface Procedures, JSC, December 31, 1970

Apollo 11 Final Lunar Surface Operations Plan, JSC, June 27, 1969

Apollo Program Summary Report, section 4.8.1 Modular Equipment Transporter, JCS-09423, April, 1975.

Apollo Program Summary Report, section 6.1.2.7 Lunar Surface Operations, JCS-09423, April, 1975.

Apollo 14 Technical Crew Debriefing, 17 February 1971, in JSC History Office.

Apollo 15 Technical Crew Debriefing, 14 August 1971, in JSC History Office.

ALSEP Termination Report, NASA Reference Publication 1036, April, 1979.

Apollo Stowage List - Apollo 17, MSC, 12 December 1972.