‘TIL Astronaut Jack Schmidt Discovered He Was Allergic to Moon Dust, Which Is a Thing….’

On August 23 2022, a Reddit account shared a screenshot to r/tumblr which suggested that astronaut Jack Schmidt discovered he was allergic to moon dust during a lunar expedition in 1972:

A long conversation appeared in the screenshot, with several Tumblr commenters discussing the claim that the astronaut was “allergic to moon dust” and speculating on the implications of that purported allergy:

Fact Check

Claim: In 1972, “astronaut Jack Schmidt discovered he was allergic to moon dust, which is a thing millions of other people have probably gone their whole lives never knowing.”

Description: In 1972, ‘astronaut Jack Schmitt discovered he was allergic to moon dust, which is a thing millions of other people have probably gone their whole lives never knowing.’

Rating: Decontextualized

Rating Explanation: Schmitt’s reaction to lunar dust or ‘moon dust’ was reported following a conference in July 2019. While it was initially described as being allergic, it was subsequently clarified that moon dust is inherently abrasive and several astronauts had reactions to the substance.

[u/ironychan] TIL astronaut Jack Schmidt discovered he was allergic to moon dust, which is a thing millions of other people have probably gone their whole lives never knowing.

[u/ironychan] Imagine being one of only twelve guys ever to have the honour of walking on the moon and then when you get there you’re allergic to it.

[u/sanctferum] NASA scientist: you’re back early
Jack Schmidt: moon’s an allergen
NASA scientist: …what?
Jack Schmidt, loading an epipen and climbing back into the shuttle: moon’s an allergen

[u/kesonafyren] if one in twelve humans who have been on the moon was allergic to moon dust, that’s either a one-in-a-million chance or a VERY common allergy

[u/haltraveler] The fact that it’s such a statistically useless sample is DEFINITELY driving a handful of very specialized scientists absolutely crazy

A third comment in the exchange referenced the “moon’s haunted” Twitter snowclone, originating with this tweet:

Search indicated that the Tumblr discussion about astronaut Jack Schmidt’s moon allergy dated back to at least 2020. Tumblr material wasn’t always clearly dated, but it appeared the initial u/ironychan post was from August 2019.

A search restricted to results published in and before August 2019 were sparse, also revealing that the virally popular Tumblr post misspelled the astronaut’s last name (Schmitt); a corrected search with the same chronological parameters had similar results.

An undated page on a NASA.gov sub-site (“The Dangerous Truth Behind Lunar Dust”) mentioned Schmitt’s allergic response, and offered that a sensitivity to moon dust is not unheard of:

During the first lunar missions, NASA discovered the dangerous nature of the moon’s dust. So as we get ready to head back, are we ready to deal with lunar dust?

Historically, some astronauts have had negative reactions to the moon’s dust. In 1972, Apollo 17’s Harrison ‘Jack’ Schmitt experienced a momentary sneezing fit, red eyes, itchy throat and clogged sinuses in response to lunar dust.


“The surface of the moon is dusty – and nasty. The Apollo astronauts quickly learned that the sharp grains of moon dust could tear spacesuits and irritate their lungs, but now it seems the lunar surface is even worse for human health than we thought.”

Broadly, information about Schmitt’s moon dust allergy appeared to originate with his appearance at a conference in 2019. A July 2019 Newsweek.com item quoted Schmitt, who said a flight surgeon also had a severe reaction to lunar dust:

Schmitt was speaking at the Starmus Festival held in Zurich, Switzerland, last month when he started talking about his experience of walking on the Moon. The 84-year-old, who was part of the Apollo 17 mission, landed on the lunar surface on December 11, 1972 … According to the U.K.’s Daily Telegraph, he told the Starmus audience about his experience of inhaling Moon dust: “First time I smelled the dust I had an allergic reaction, the inside of my nose became swollen, you could hear it in my voice. But that gradually went away for me, and by the fourth time I inhaled lunar dust I didn’t notice that.

“Whereas a flight surgeon taking suits out of the Apollo 17 command module, after we had splashed down, he had such a reaction that he had to stop doing what he was doing.”

Schmitt was also quoted in a 2005 Wired.com piece about moon dust (described as glass-like and “abrasive”) and its relevance to possible future lunar missions:

Lunar dust is extremely abrasive — and unavoidable — as astronauts quickly learned during the Apollo missions of the 1960s and ’70s. Within hours, the dust covered the astronauts’ spacesuits and equipment, scratching lenses and corroding seals.

Fortunately for the astronauts, their contact with lunar dust was short enough that it didn’t cause any major problems. But explorers living on a moon base for weeks or even months at a time are not likely to get away so clean.

Under prolonged exposure, the explorers would be at risk for everything from mechanical failures in spacesuits and airlocks to lung disease, said researchers last week at a NASA workshop focused on the issue.

“Dust is the No. 1 environmental problem on the moon,” said Apollo 17 astronaut Harrison Schmitt, who reported having a severe allergic reaction to moon dust during his mission in 1972. “We need to understand what the (biological) effects are, because there’s always the possibility that engineering might fail.”

A slightly longer Tumblr conversation on the same thread included a comment from u/squeeful, once again without any link to additional information:

oh this one i know! he’s not actually allergic and he’s not a statistical outlier. all twelve astronauts reported symptoms after stepping on the moon because lunar soil is fucking nasty to human (and presumably most complex life) biology. moon dust is like inhaling asbestos. it’s very fine, chemically reactive, and will hang around in your lungs for months, like a shitty inhaled cloud of glass. which, as it’s mostly silicon, it kind of is. glass powder that is ripping up your airways and possibly your dna. see again: like asbestos

That assertion was echoed in a July 2019 ScienceTimes.com piece about moon dust, “Last Man to Walk the Moon Warns About Moon Dust Allergy.” It indicated that another individual (the flight surgeon) had a severe reaction, and noted:

The astronaut [Schmitt] suggested that some individuals need to be tested for allergic reactions if they are going to be exposed chronically the moon dust. Learning that NASA is once again sending people to the moon in a few years, it is critical for concerned experts to know that Schmitt suggests avoiding exposure to lunar dust at all costs. If there are many engineering solutions since he flew, the astronaut suggested keeping the dust out of the cabin and the suit as well.

He pointed out that this factor is primarily an engineering problem.

Larry Taylor, the director of Planetary Geosciences Institute stated that the common problem that Apollo Mission astronauts have pointed out is the moon dust. Some astronauts reported that the dust had stayed on their suits even though they have brushed it off. Experts pointed out that moon dust is sharp and abrasive despite looking like pillowy powder with a soft texture. This is because there is no wind or flowing water on the moon that could round the edges of the moon dust particles.

On August 23 2022, a popular Reddit post suggested that Astronaut Jack [Schmitt] “discovered he was allergic to moon dust, which is a thing millions of other people have probably gone their whole lives never knowing.” Schmitt’s reaction to lunar dust (or “moon dust”) entered the news cycle after it came up at a July 2019 conference. Schmitt reported having a reaction, and said another person involved with the mission also reacted to the substance. However, several astronauts and other experts explained that moon dust is inherently abrasive, and added that controlling lunar dust was a common topic when discussing and planning future lunar missions.