Marusuke's Naruhodo Lab日本語People walked on the Moon over 50 years ago. So why is NASA offering prize money over static electricity now?
That winter zap from a doorknob. Good old static electricity.
On the Moon, though, NASA has put up as much as $150,000 in prizes for ways to prevent the same kind of zap.
But people walked on the Moon more than 50 years ago, with Apollo. So why now?
First guess
“Because your boots rub against the lunar soil as you walk?”
Half right. Rubbing makes charge on a carpet on Earth, too. So why is it a big problem on the Moon?
Answer
Because Apollo walked in sunlight near the equator, while the next astronauts will walk near the Moon's south pole, a place full of shadows.
The Moon has no moisture to carry charge away, and in shadow the escape route through the surrounding plasma also narrows, so a spacesuit can build up a large negative charge.
If that astronaut touches a lander parked in sunlight, a spark could damage the suit or its equipment, so NASA is seeking ways to drain the charge before contact.
Watch the video (7 min 28 sec)
Chapters (18)
- 0:00A doorknob zap, and NASA's $150,000
- 0:12We walked on the Moon 50 years ago. Why now?
- 0:39NASA's call for ideas
- 1:01A walking, high voltage capacitor
- 1:27Rejected: "Because they rub"?
- 1:42Static on Earth
- 2:03Quiz: how many volts on a humid day?
- 2:41The key: the escape route
- 3:14The bathtub analogy
- 3:35Escape routes on the Moon
- 4:24In shadow, the suit goes negative
- 4:51What's different from Apollo?
- 5:10The south pole: a Moon of shadows
- 5:30Touch, and zap
- 5:44What's so bad about a Moon spark?
- 6:10The romance is in the shadows, too
- 6:31What we learned
- 7:03How would you drain the charge?
Full transcript
0:00A doorknob zap, and NASA's $150,000
NaruIn winter, you touch a doorknob, and zap. Good old static electricity.
NaruBut on the Moon, NASA has put up as much as 150,000 dollars in prizes to prevent that same kind of zap.
0:12We walked on the Moon 50 years ago. Why now?
NaruBut people walked on the Moon more than fifty years ago, with Apollo.
NaruSo why now?
DirectorSpace is romance! Go find out!
NaruThe Director says space is romance, so why prize money now, for something as plain as static? He wants me to find out.
NaruThe answer was in the escape route for the charge, and in the shadows of the Moon.
NaruMarusuke's Naruhodo Lab!
0:39NASA's call for ideas
NaruFirst, the news. This is a call for ideas that NASA opened on October 5th.
NaruWhat they want is a way to drain an astronaut's charge safely and quickly, before they touch the lander.
NaruEntries close on January 15th, 2027. The prizes add up to as much as 150,000 dollars.
1:01A walking, high voltage capacitor
NaruAccording to NASA, walking on the lunar surface builds up charge through rubbing. And it gets much worse in shadows and places that never see the Sun.
NaruNASA even writes that an astronaut may become "a walking, high voltage capacitor."
NaruSo what is a capacitor?
NaruIt is a part that stores electric charge. In other words, the astronaut becomes a walking part that stores charge.
1:27Rejected: "Because they rub"?
NaruI've got it! It's because they rub against the lunar soil as they walk. Done!
DirectorRejected!
Naru...He says carpets on Earth rub too. So why is it such a big deal on the Moon?
1:42Static on Earth
NaruOkay, let's start over with static on Earth.
NaruAccording to a US association that works on static control, when two things touch and then separate, charge can move from one to the other.
NaruIn dry winter, the charge that has built up rushes out all at once through a metal doorknob, which conducts electricity easily. That's the zap.
2:03Quiz: how many volts on a humid day?
NaruThat same association's table gives an example of walking across carpet. On a dry day, at 10 to 25 percent humidity, about 35,000 volts.
NaruQuiz time!
NaruSo in the humid example, at 65 to 90 percent humidity, how many volts? A: about 30,000. B: about 10,000. C: about 1,500.
NaruThe answer is C: about 1,500 volts. It's an example listed in a table, without detailed conditions, but that's a lot smaller.
2:41The key: the escape route
NaruCharge is made on humid days too. So why such a big difference?
NaruWhen the air is humid, depending on the material, a thin film of water forms on the surface. Charge can leak away more easily along that water.
NaruHumidity also affects how much charge is made, but this is one of the big reasons static builds up so easily in winter.
NaruSo the key is the escape route for the charge.
NaruSo what are the escape routes like on the Moon? And why are shadows dangerous? Let's take a look.
3:14The bathtub analogy
NaruThink of a bathtub. Water from the faucet is the charge being made. Water going down the drain is the charge escaping. If the drain is narrow, the tub fills up fast.
NaruHere on Earth, we can widen that drain. In the dry season, a humidifier gives the charge more ways out.
3:35Escape routes on the Moon
NaruBut on the Moon, it's not that simple.
NaruThe Moon has almost no atmosphere like Earth's. So you can't count on an escape route through water on a damp surface.
NaruOn top of that, lunar rock and soil conduct electricity very poorly, and even worse as they get colder.
NaruSo the main escape route is the surrounding plasma: tiny particles that carry charge.
NaruSo does charge just keep piling up everywhere on the Moon?
NaruActually, calculations show that where the surrounding plasma reaches you unblocked, the extra charge from walking escapes fairly quickly.
NaruIt depends on conditions, but in sunlight, light knocks electrons loose, so things tend toward plus. In shadow, they tend toward minus.
4:24In shadow, the suit goes negative
NaruBut inside the south pole's craters, in shadows, and on the night side, even the plasma escape route gets narrow.
NaruThe drain gets narrow. According to NASA, in shadow, electrons keep coming in, but positive particles have trouble reaching you, and there's no sunlight to knock electrons back out. So a spacesuit can build up a large negative charge.
4:51What's different from Apollo?
NaruNow, back to our first question. People walked on the Moon more than fifty years ago. What is different from Apollo?
NaruAll six Apollo landing sites were near the equator. They landed in the lunar morning and worked in daylight that lasted for days.
5:10The south pole: a Moon of shadows
NaruBut this time, the candidate landing sites are near the lunar south pole. The Sun just circles near the horizon, shadows are long, and some places never see sunlight at all.
NaruApollo walked on a sunlit Moon. From now on, astronauts will walk on a Moon full of shadows. The places they go are completely different.
5:30Touch, and zap
NaruAn astronaut who has walked through shadow and built up a large negative charge touches a lander parked in the sunlight, which is slightly positive...
NaruJust like the doorknob: zap. A spark could jump.
5:44What's so bad about a Moon spark?
NaruSo what is so bad about a spark on the Moon?
NaruAccording to NASA, a spark could damage vital layers of the spacesuit and break the suit's electronics.
NaruIt could threaten the oxygen-rich environment inside the suit, and give the astronaut a dangerous shock.
NaruA spark, right on the suit that keeps them alive. That's why NASA is offering prize money for a way to drain the charge before they touch.
6:10The romance is in the shadows, too
DirectorSo where's the romance?
NaruOh, there's romance, too.
NaruIn some places near the lunar south pole that never see sunlight, evidence of water ice has been found.
NaruThe ice evidence is found where the Sun never shines, and that's also where static can build up. The romance and the challenge were both in the shadows.
6:31What we learned
NaruSo the reason the Moon zap is a big deal now is that people are about to walk the shadowy south pole. The moment an astronaut charged up in shadow touches a sunlit lander, a spark could jump on the life-saving spacesuit.
NaruWith static, look not just at how much charge is made, but at its escape route. On Earth or on the Moon, it was the same. Naruhodo!
Director...I see. Space really is romance.
NaruAnd the Director approved it!
7:03How would you drain the charge?
NaruIf it were you, how would you drain an astronaut's charge on the Moon? Share your ideas in the comments.
NaruThis has been Marusuke's Naruhodo Lab!
NaruIf you went "naruhodo!", please hit like and subscribe!
See it in pictures
More details
Why is static electricity on Earth worse in winter?
When two things touch and separate, charge can move from one to the other. That is static electricity.
In a table from the ESD Association, a US association working on static control, walking across carpet is listed at about 35,000 volts at 10–25% humidity and about 1,500 volts at 65–90% humidity. (These are typical examples from a table, and the detailed conditions are not given, so they can't be treated as a strict measure of the effect of humidity alone.)
Charge is made on humid days too. When humidity is high, depending on the material, a thin film of water forms on surfaces, and charge leaks away more easily along it. That is one big reason static builds up in winter (humidity also affects how much charge is made).
Where does charge go on the Moon?
The Moon has almost no atmosphere like Earth's, so you can't count on moisture to carry charge away. Lunar rock and soil conduct electricity very poorly, and even worse as they get colder.
The main escape route is the surrounding plasma (tiny charged particles). Calculations show that where the plasma reaches you unblocked, the charge from walking escapes fairly quickly.
It depends on conditions, but sunlit places tend to lean positive, because sunlight knocks electrons out, and shadowed places tend to lean negative. Inside polar craters, in shadows, and on the night side, the plasma escape route narrows too.
What's different from Apollo?
All six Apollo landing sites (1969–1972) were near the equator. Astronauts landed in the lunar morning and worked in daylight that lasted for days.
This time, the candidate landing sites are near the lunar south pole. The Sun just circles near the horizon, shadows are long, and some places never see sunlight.
What's so bad about a spark on the Moon?
According to NASA, a spacesuit picks up charge from walking and from the surrounding plasma. NASA even says an astronaut may become “a walking, high voltage capacitor” (a capacitor is a part that stores electric charge).
A spark at the moment of contact could damage vital suit layers and electronics, threaten the oxygen-rich environment inside the suit, and give the astronaut a dangerous shock.
What is NASA looking for?
Since October 5, 2026, NASA has been seeking ways to drain an astronaut's charge safely and quickly before they touch the lander. Prizes total up to $150,000, and entries close January 15, 2027.
Where's the romance?
In some places near the lunar south pole that never see sunlight, evidence of water ice has been found. The evidence of ice and the static puzzle were both in the shadows.
TakeawayWith static, look not only at how much charge is made, but also at where it can escape. On Earth and on the Moon alike.
How we checked
- NASA, "Lunar Grounding Challenge" (open from October 5, 2026)
- ESD Association, "Fundamentals of Electrostatic Discharge, Part One: An Introduction to ESD"
- Jackson et al., "The Discharging of Roving Objects in the Lunar Polar Regions" (NASA technical report)
- NASA, "The Lunar South Pole Region"
- NASA, "Why the Lunar South Polar Region?"
- NASA Scientific Visualization Studio, "From Apollo Sites To The South Pole"
People and several AIs checked the video script against the text of the sources above and fixed misleading wording (October 14, 2026). Numbers are as of that date. AI wrote this page from that script and those sources, and a person checked it before publishing. If you spot a mistake, please email marusukelab@gmail.com.