How Can Astronauts Tell How Fast They’re Going?Let’s use our car again, but this time we’ll get real numbers from the accelerometer in our smartphone. Say we start at a red light and then accelerate at 2 m/s2 (meters per second squared) for five seconds. From the equation above, Δv1 would be 2 x 5 = 10 m/s, so that’s our velocity. Now, after cruising for a while, we accelerate again at 1 m/s2 for five more seconds. Δv2 is then 1 x 5 = 5 m/s. Adding these two changes, our velocity is now 15 m/s. And so on.
The only problem is that inertial measurement isn’t as accurate as the Doppler method over long periods, because small errors will keep accumulating. That means you need to recalibrate your system periodically using some other method.
Optical Navigation
On Earth, people have long navigated by the stars. In the northern hemisphere, just find Polaris. It’s called the North Star because Earth’s axis of rotation points right at it. That’s why it appears stationary, while the other stars seem to revolve around it. If you point a finger at Polaris you’ll be pointing north, and you can use that orientation to go in whatever direction you want.
Now, if you can measure the angle of Polaris above the horizon, you’ll also know your latitude. If the angle is 30 degrees, you’re at latitude 30 degrees. See, it’s easy. And once you can measure position, you just need to do it twice and record the time interval to find your velocity.
But celestial navigation works because we know how the Earth rotates, and that doesn’t help in a spacecraft. Oh well, can we just use the stars like you would use the cows on the side of the road? Nope. The stars are so far away, astronauts would need to travel for many, many generations to detect any shift in their position. Like the airplane flying over the sea, you’d seem to be stationary, even while traveling 25,000 mph.
But we can still use the basic idea. For optical navigation in space, a spacecraft can locate other objects in the solar system. By knowing the precise location of these objects (which change over time) and where they appear relative to the viewer, it’s possible to triangulate a position. And again, by taking multiple position measurements over time, you can calculate a velocity.
In the end, even though spaceships lack speedometers, it’s possible to track their speed indirectly with a little physics. But it’s just another example of how flying in space is really, totally different—and way more complicated—than driving or flying on Earth.
#Astronauts #Fast #Theyredot physics,physics,astronomy,space,spacecraft,moon landing,navigation,acceleration
Let’s use our car again, but this time we’ll get real numbers from the accelerometer in our smartphone. Say we start at a red light and then accelerate at 2 m/s2 (meters per second squared) for five seconds. From the equation above, Δv1 would be 2 x 5 = 10 m/s, so that’s our velocity. Now, after cruising for a while, we accelerate again at 1 m/s2 for five more seconds. Δv2 is then 1 x 5 = 5 m/s. Adding these two changes, our velocity is now 15 m/s. And so on.
The only problem is that inertial measurement isn’t as accurate as the Doppler method over long periods, because small errors will keep accumulating. That means you need to recalibrate your system periodically using some other method.
Optical Navigation
On Earth, people have long navigated by the stars. In the northern hemisphere, just find Polaris. It’s called the North Star because Earth’s axis of rotation points right at it. That’s why it appears stationary, while the other stars seem to revolve around it. If you point a finger at Polaris you’ll be pointing north, and you can use that orientation to go in whatever direction you want.
Now, if you can measure the angle of Polaris above the horizon, you’ll also know your latitude. If the angle is 30 degrees, you’re at latitude 30 degrees. See, it’s easy. And once you can measure position, you just need to do it twice and record the time interval to find your velocity.
But celestial navigation works because we know how the Earth rotates, and that doesn’t help in a spacecraft. Oh well, can we just use the stars like you would use the cows on the side of the road? Nope. The stars are so far away, astronauts would need to travel for many, many generations to detect any shift in their position. Like the airplane flying over the sea, you’d seem to be stationary, even while traveling 25,000 mph.
But we can still use the basic idea. For optical navigation in space, a spacecraft can locate other objects in the solar system. By knowing the precise location of these objects (which change over time) and where they appear relative to the viewer, it’s possible to triangulate a position. And again, by taking multiple position measurements over time, you can calculate a velocity.
In the end, even though spaceships lack speedometers, it’s possible to track their speed indirectly with a little physics. But it’s just another example of how flying in space is really, totally different—and way more complicated—than driving or flying on Earth.






![‘Witch Hat Atelier’ Creator, Coco Star on How the Anime Exceeded Expectations
As far as contemporary anime is concerned, the “big three” fantasy series have finally been christened, thanks to the wondrous arrival of the last in its holy trinity on Crunchyroll: Bug Films’ absolutely magical adaptation of Kamome Shirahama‘s beloved manga, Witch Hat Atelier. At Anime Expo 2026, io9 got to speak with Shirahama and Coco’s Japanese voice actor, Rena Motomura, about how Bug Films utilized its production delay to deliver an adaptation that honored, and occasionally outshone, the artistry of its source material, what keeps the anime community’s newly adopted daughter so optimistic in an insane world, and whether Pointed Cap witches or Brimmed Caps have the best sense of fashion. Kamome Shirahama’s Brushbuddy. © Isaiah Colbert/io9 Isaiah Colbert, io9: During the anime’s delay, Bug Films announced that certain scenes needed additional time and attention, hoping the anime would be as big as The Lord of the Rings for anime fans. What scenes from this season exceeded your expectations?
Rena Motomura: There are so many scenes that exceeded my expectations. But in episode one, at the end, when Coco’s screaming, “Mom,” and then Qifrey takes her up into the sky as the magic is being triggered, they’re skyward and having that moment together—I saw a bit of it in the teaser—but when I saw it in the anime episode, it made me so emotional. I saw exactly how my sensei’s world was being brought to life in anime form, and how the frames were coming together to tell this story. That’s when I knew with great conviction that we were going to have something really special on our hands.
[embed]https://www.youtube.com/watch?v=ZSGVFk9w5qA[/embed] Kamome Shirahama: This was really talked about a lot, but episode five, for me personally, when I saw it, I was super wowed. It made me really feel like I was watching a film in the theater. [embed]https://www.youtube.com/watch?v=E9URbx38AIY[/embed] io9: Shirahama‑sensei, your live‑tweeting during the broadcast has delighted fans—especially when you pose questions about characters as if you didn’t write them. Which aspects of the anime were your favorites to see realized on screen—and for Motomura‑san, which scenes were the most memorable or rewarding for you to record as Coco?
Shirahama: Yeah, for sure. There’s things that you can see in the anime that the manga doesn’t contain—certain elements that make the world more expansive, more brilliant, more rich, and colored. Those are the things I was looking forward to the most. Motomura: For me, it’s the last scene in the dragon maze when Coco has this realization that her actions have put everyone into danger and she’s tearing up, saying, “I’m really sorry that this happened.” Up until that point, she’s been really cheerful. Really sort of outgoing. But then you realize that deep inside her heart, she’s been carrying a lot of this anxiety and worry that’s just piling up. As I was playing the character through the scene, it reminded me of how, through episodes one to three, there must have been a lot of internal thoughts—a lot of anxiety and worry. And that part I empathize with. I started tearing up doing the scene. And even when I look back on it now, I start tearing up. io9: For many, Coco embodies hope and determination, even when the world around her feels overwhelming or insane. How does each of you interpret the way her character maintains that sense of glowing optimism, and what does she represent to you within the story?
Shirahama: Coco’s greatest motivation is her love for magic. Even when she faces situations that are fearful or scary, she knows that’s not all there is to magic. And she knows that there’s hope. And she holds on to that hope as her core belief. And that’s what moves her forward. Motomura: Coco has this enormous admiration for magic. I think as long as she holds on to that admiration, she’ll be able to keep moving forward. In the story, I believe her existence is like the mast of a ship. She is a very certain presence in the story, and deep inside her heart—at her core—she holds on to this admiration for magic that’s going to carry everything forward.
[embed]https://www.youtube.com/watch?v=jA1sPU4F1n4[/embed] io9: This season introduced a variety of intricate, hand-drawn spells. Of the spells featured so far, which one stands out as your personal favorite, and why? Motomura: For me, it’s the very first spell that Coco came up with for herself—the straight arrow that carries her up into the sky in her time of need as she’s flying upwards. I really felt like this spell was an embodiment of her personality. In this moment, she has nothing. She has no skills, no knowledge, nothing. But she has to do something. So she comes up with this spell to help her get out of a tough situation. The name, too, is super cute. I believe Shirahama-sensei named it 空すっ飛び (sorasuttobi/Skysoaring Seal) in Japanese. Shirahama: For me, it’s the spell that Qifrey casts in episode six when they’re trying to have a picnic in the rain, so he creates this bubble where the rain can’t touch them. I’m so jealous because we get a lot of rain in Japan, and I feel like that would be a great spell to have when you have to walk your dog in the rain.
[embed]https://www.youtube.com/watch?v=Yu0qoRHqDt8[/embed] io9: If you had to choose—based on fashion alone, no morals at play—would you see yourselves more as the Pointed Cap witches in Witch Hat Atelier or one of the Brimmed Caps? Motomura: Oh! That’s a very difficult question. But personally, I have a bit of an ambition for the Brimmed Caps because ever since I was a child, I thought those kinds of hats were very cool. And then when I came into the world of Witch Hat Atelier, the fact that they cover their face so they can practice forbidden magic, I was like, “Oh, that is so cool.” I know that, morally speaking, as Coco, it’s a questionable answer. But I really like the Brimmed Caps…just as fashion! Shirahama: (Laughs) I feel like the Brimmed Caps might be more popular in a place like California, where you guys get so much sun. For me, personally, I really like the silhouette of the Pointed Caps, so I prefer those.
Witch Hat Atelier is streaming on Crunchyroll, and season two is in production. io9 is on the ground at Anime Expo 2026. We’ll be bringing you updates on all the biggest panels, screenings, and announcements, plus exclusive one-on-one interviews with the people behind some of the best and most popular anime around. You can check out all of io9’s Anime Expo coverage here. Want more io9 news? Check out when to expect the latest Marvel, Star Wars, and Star Trek releases, what’s next for the DC Universe on film and TV, and everything you need to know about the future of Doctor Who. #Witch #Hat #Atelier #Creator #Coco #Star #Anime #Exceeded #ExpectationsAnime,Anime Expo,Bug Films,Kamome Shirahama,Witch Hat Atelier ‘Witch Hat Atelier’ Creator, Coco Star on How the Anime Exceeded Expectations
As far as contemporary anime is concerned, the “big three” fantasy series have finally been christened, thanks to the wondrous arrival of the last in its holy trinity on Crunchyroll: Bug Films’ absolutely magical adaptation of Kamome Shirahama‘s beloved manga, Witch Hat Atelier. At Anime Expo 2026, io9 got to speak with Shirahama and Coco’s Japanese voice actor, Rena Motomura, about how Bug Films utilized its production delay to deliver an adaptation that honored, and occasionally outshone, the artistry of its source material, what keeps the anime community’s newly adopted daughter so optimistic in an insane world, and whether Pointed Cap witches or Brimmed Caps have the best sense of fashion. Kamome Shirahama’s Brushbuddy. © Isaiah Colbert/io9 Isaiah Colbert, io9: During the anime’s delay, Bug Films announced that certain scenes needed additional time and attention, hoping the anime would be as big as The Lord of the Rings for anime fans. What scenes from this season exceeded your expectations?
Rena Motomura: There are so many scenes that exceeded my expectations. But in episode one, at the end, when Coco’s screaming, “Mom,” and then Qifrey takes her up into the sky as the magic is being triggered, they’re skyward and having that moment together—I saw a bit of it in the teaser—but when I saw it in the anime episode, it made me so emotional. I saw exactly how my sensei’s world was being brought to life in anime form, and how the frames were coming together to tell this story. That’s when I knew with great conviction that we were going to have something really special on our hands.
[embed]https://www.youtube.com/watch?v=ZSGVFk9w5qA[/embed] Kamome Shirahama: This was really talked about a lot, but episode five, for me personally, when I saw it, I was super wowed. It made me really feel like I was watching a film in the theater. [embed]https://www.youtube.com/watch?v=E9URbx38AIY[/embed] io9: Shirahama‑sensei, your live‑tweeting during the broadcast has delighted fans—especially when you pose questions about characters as if you didn’t write them. Which aspects of the anime were your favorites to see realized on screen—and for Motomura‑san, which scenes were the most memorable or rewarding for you to record as Coco?
Shirahama: Yeah, for sure. There’s things that you can see in the anime that the manga doesn’t contain—certain elements that make the world more expansive, more brilliant, more rich, and colored. Those are the things I was looking forward to the most. Motomura: For me, it’s the last scene in the dragon maze when Coco has this realization that her actions have put everyone into danger and she’s tearing up, saying, “I’m really sorry that this happened.” Up until that point, she’s been really cheerful. Really sort of outgoing. But then you realize that deep inside her heart, she’s been carrying a lot of this anxiety and worry that’s just piling up. As I was playing the character through the scene, it reminded me of how, through episodes one to three, there must have been a lot of internal thoughts—a lot of anxiety and worry. And that part I empathize with. I started tearing up doing the scene. And even when I look back on it now, I start tearing up. io9: For many, Coco embodies hope and determination, even when the world around her feels overwhelming or insane. How does each of you interpret the way her character maintains that sense of glowing optimism, and what does she represent to you within the story?
Shirahama: Coco’s greatest motivation is her love for magic. Even when she faces situations that are fearful or scary, she knows that’s not all there is to magic. And she knows that there’s hope. And she holds on to that hope as her core belief. And that’s what moves her forward. Motomura: Coco has this enormous admiration for magic. I think as long as she holds on to that admiration, she’ll be able to keep moving forward. In the story, I believe her existence is like the mast of a ship. She is a very certain presence in the story, and deep inside her heart—at her core—she holds on to this admiration for magic that’s going to carry everything forward.
[embed]https://www.youtube.com/watch?v=jA1sPU4F1n4[/embed] io9: This season introduced a variety of intricate, hand-drawn spells. Of the spells featured so far, which one stands out as your personal favorite, and why? Motomura: For me, it’s the very first spell that Coco came up with for herself—the straight arrow that carries her up into the sky in her time of need as she’s flying upwards. I really felt like this spell was an embodiment of her personality. In this moment, she has nothing. She has no skills, no knowledge, nothing. But she has to do something. So she comes up with this spell to help her get out of a tough situation. The name, too, is super cute. I believe Shirahama-sensei named it 空すっ飛び (sorasuttobi/Skysoaring Seal) in Japanese. Shirahama: For me, it’s the spell that Qifrey casts in episode six when they’re trying to have a picnic in the rain, so he creates this bubble where the rain can’t touch them. I’m so jealous because we get a lot of rain in Japan, and I feel like that would be a great spell to have when you have to walk your dog in the rain.
[embed]https://www.youtube.com/watch?v=Yu0qoRHqDt8[/embed] io9: If you had to choose—based on fashion alone, no morals at play—would you see yourselves more as the Pointed Cap witches in Witch Hat Atelier or one of the Brimmed Caps? Motomura: Oh! That’s a very difficult question. But personally, I have a bit of an ambition for the Brimmed Caps because ever since I was a child, I thought those kinds of hats were very cool. And then when I came into the world of Witch Hat Atelier, the fact that they cover their face so they can practice forbidden magic, I was like, “Oh, that is so cool.” I know that, morally speaking, as Coco, it’s a questionable answer. But I really like the Brimmed Caps…just as fashion! Shirahama: (Laughs) I feel like the Brimmed Caps might be more popular in a place like California, where you guys get so much sun. For me, personally, I really like the silhouette of the Pointed Caps, so I prefer those.
Witch Hat Atelier is streaming on Crunchyroll, and season two is in production. io9 is on the ground at Anime Expo 2026. We’ll be bringing you updates on all the biggest panels, screenings, and announcements, plus exclusive one-on-one interviews with the people behind some of the best and most popular anime around. You can check out all of io9’s Anime Expo coverage here. Want more io9 news? Check out when to expect the latest Marvel, Star Wars, and Star Trek releases, what’s next for the DC Universe on film and TV, and everything you need to know about the future of Doctor Who. #Witch #Hat #Atelier #Creator #Coco #Star #Anime #Exceeded #ExpectationsAnime,Anime Expo,Bug Films,Kamome Shirahama,Witch Hat Atelier](https://gizmodo.com/app/uploads/2026/07/kamome-shirahama-witch-hat-atelier.jpg)
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