Experiment Operation During Apollo IVA at 0-g

Experiment: Electrophoresis or Electrophoretic Separation

Acronym: None

PI/Engineer: R. N. Griffin/GE, L. R. McCreight/GE
Other Contacts: E. C. McKannan/MSFC, A. C. Krupnick/MSFC

Apollo Flight Nos.: 14
Apollo Exp't No. none

Discipline: materials science - organics/proteins (2680)

Weight: 2.3 kg
Dimensions: 10 x 12.7 x 18 cm

Manufacturer: Marshall SFC (Possibly with General Electric)

Description/Purpose:
Many organic molecules, when placed in water solutions, will migrate if an electric field is applied. Molecules of different substances move at different speeds; thus, they will separate. Gravity and thermal convection tend to diminish this separation if solution density changes upon concentration of these species. A small unit was used to demonstrate the separations obtained with 3 sample mixtures having widely different molecular weights: 1) a mix of red and blue organic dyes, 2) human hemoglobin, and 3) DNA from salmon sperm.

The experiment consisted of 4 sub-systems. First, a metal case for safety and containment with a window ~5 x 7.6 cm. Second, a pump to circulate the electrolytic fluid (that which flowed over the electrodes - not the fluid in which the separation occurred since it was a static separation), a fluorescent light for viewing the action in the tubes, and a voltage doubler/rectifier. Third, the electrophoresis cells were in a polycarbonate block, 12.7 x 7.6 x 1.27 cm with 3 holes drilled through the long dimension to provide the 0.63 cm diameter test tubes. The fluid in the cells did not flow and was enclosed at the ends by cellulose membranes with a pore size of 4 to 5 microns. Hence, the electrodes at each end of the tubes were separated from the specimens in their solution. The 4th subsystem provided circulation of electrolyte through the six electrode compartments. In operation, the electrodes were continuously flushed by the flowing electrolyte which had the same composition as the solvent, which maintained constant pH in the electrode compartments by being interchanged between the anode and cathode ends. It also removed gaseous products from the vicinity of the electrodes.

Unloading from the LM: NA

Transporting by foot or MET: NA

Loading/unloading tools/exp'ts on LRV: NA

Site Selection: NA

Deploying experiment: No comments by crew.

Check-out of experiment: No comments by crew.

Operation of experiment:
The unit had two switches on it: one for power (on/off) and one to control the lighting (off/white/UV). Samples were released into the tubes by operating a slide valve. Data on the progress of electrophoresis was collected by taking a sequence of photographs at intervals of 2.5 to 5 minutes of the action in the tubes through the window of the case with a 70 mm Hasselblad. The total time required to demonstrate the separations was 57 minutes. The color bands were so faint that they were difficult to see by eye. The crew was doubtful as to whether they would show up on film, but they did. The other two experiments did not appear to work at all according to the crew debriefs.

Post-mission review of the filmed data reveals that the red and blue organic dyes separated better and sharper than on Earth, as expected; however, separation of the hemoglobin and DNA could not be detected. Post-flight examination of the apparatus indicated that the samples were not released effectively (due to injection problems caused by the slide valve) to permit good separation, causing the dyes to streak. The hemoglobin and DNA samples did not separate because they contained bacteria that consumed the organic molecules prior to activation of the apparatus.

Repairs to experiment: None attempted.

Recovery/take-down of experiment:
The apparatus was returned after 60 days of quarantine at the lunar receiving lab. The photos were obtained shortly after splashdown.

Stowing experiment for return: No comments by crew.

Loading/unloading samples: The samples were injected into the tubes through a slide valve. It did not operate properly and the samples were placed in a region of maximum electro- osmotic shear, which degraded the separation.

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

Navigating/recognizing landmarks: NA

Were there any hazards in the experiment?
i.e. hazardous materials (explosive, radioactive, toxic), sharp objects, high voltages, massive, bulky, tripping hazards, temperatures?
The electrical system produced 270 VDC for the electrodes for separation. The crew was protected from this.

Was lighting a problem? No

Were the results visible to the crew? Yes

Would you recommend any design changes?
The slide valve, allowing for the release of the samples, did not fully open due to misalignment between the cell block and the case. This was corrected for A-16. A means of measuring the distance of the camera to the experiment might have helped the focus. A tripod was added to the A-16 unit to allow the camera to be held more steadily and at a fixed distance and two M-21 Hasselblad lens extension tubes were included to take close-up pictures with the correct range and focus. The window was enlarged so that the electrodes could also be seen. Time, temperature and current measurement capabilities were also added and were visible in the window for A-16. Markings 1 cm apart were added to the tubes for aid in measurements. The anode was identified by yellow paint. Nondegradable samples (polystyrene spheres) were used for A-16.

Were any special tools required?
Camera for filming.

Was the orientation of the experiment (i.e. horizontal/vertical) important? Difficult? No

Was the experiment successful?
The red and blue dyes did separate, but the DNA and hemoglobin was not verified to be separated. Bacterial contamination followed by digestion of the material was suspected. Nevertheless, the dye separation successfully demonstrated the process.

Were there related experiments on other flights?
Apollo16 Electrophoresis Experiment, Skylab, Shuttle middeck (EOS), Spacelab(?)

Where was it stored during flight?
CM aft bulkhead locker A8.

Were there any problems photographing the experiment?
No, but some of the photos were out of focus. The experiment was performed on trans-Earth coast with live color television during a press conference. It was also filmed.

What pre-launch and cruise req'ts were there?
The photos were recovered upon splashdown. The apparatus itself had to go through the Lunar Receiving Lab (LRL) quarantine. The unit might have performed better if last minute loading of the electrolytic fluids and samples, to minimize the opportunity for bacterial growth, had been possible.

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

What problems were due to the suit rather than the experiment?
NA

Any experiences inside the LM of interest from the experiment/operations viewpoint?
No comments by crew.

References:

A-14 Mission Report

A-16 Mission Report

NASA TM X-64611, Electrophoresis Separation in Space - Apollo 14, 1971

Apollo Program Summary Report, section 3.6 Inflight Demonstrations, JCS-09423, April, 1975.

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

Apollo Stowage List - Apollo 14, MSC, 9 February 1971