According to the Apollo Program Summary Report, page 6-14:

In zero gravity, when the food packages were rehydrated with water containing gas bubbles, the bubbles could not be removed from the food. The hydrogen gas separator used on lunar flights did not successfully remove the gas from the water on every occasion. Gas bubbles in the food and water contributed to intestinal problems experienced by the crewmen during the last two missions.

Are gas bubbles still a problem in space food? What measures are taken to abate the problem?


  • 1
    $\begingroup$ A slightly related tweet from Chris Hadfield implicates that it still is a problem. $\endgroup$
    – DarkDust
    Nov 8, 2018 at 9:43
  • 3
    $\begingroup$ Hydrogen bubbles in water from the fuel cells for electricity were a problem during the missions Apollo and Space Shuttle. But the ISS does not use liquid oxygen and hydrogen to produce electricity by fuel cells. Solar panels are used instead. $\endgroup$
    – Uwe
    Nov 8, 2018 at 15:15

1 Answer 1


This was still a problem in the early Space Shuttle program. An anomaly report from the second shuttle flight describes it:

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The 1982 press reference manual describes the H2 separator and shows a single H2 separator in the fuel cell product water line.

Potable water is generated by the three fuel cells at a maximum of 11.34 kilograms (25 lbs) per hour. The hydrogen- enriched water from the fuel cell passes through a hydrogen (H2) separator, where 95 percent of the excess hydrogen is removed. The H2 separator consists of a matrix of silver palladium tubes which have an affinity for H2. The H2 is dumped overboard through a vacuum vent.

enter image description here

In the 1988 revision of the press reference manual, a second H2 separator had been added (emphasis mine).

The hydrogen-enriched water from the fuel cell power plants that flows through the single water relief panel to potable tank A passes through two hydrogen separators, where 85 percent of the excess hydrogen is removed. The hydrogen separators consist of a matrix of silver palladium tubes, which have an affinity for hydrogen. The hydrogen is dumped overboard through a vacuum vent.

I note that the claimed percentage removal has been reduced as well.


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