Why the quality is so poor? Looks like taken from a digital camera from 2000.
bandwidth perhaps?
Japan's zero-gravity space drone sends first pictures from ISS
61–70 of 89 posts
Re: Japan's zero-gravity space drone sends first pictures from ISS
#62Earlier quoted context omitted.
The brake is an internal force though (the force and its reaction both act on the bicycle). The whole unit's only external forces are from the fans so that's all it can use to translate. That and bumping into things.
> That and bumping into things. Come to think of it - in air you're constantly bumping into things - air molecules. I think it could technically be possible to steer in zero-g within an atmosphere by pure rotation (e.g. consider that a fast-spinning object is kind of a (crappy) fan).
And, in fact, that's what this device does.
It uses an array of 12 small rotating fans placed around its surface to push jets of air and move itself from place to place.
Re: Japan's zero-gravity space drone sends first pictures from ISS
#63Earlier quoted context omitted.
> That and bumping into things. Come to think of it - in air you're constantly bumping into things - air molecules. I think it could technically be possible to steer in zero-g within an atmosphere by pure rotation (e.g. consider that a fast-spinning object is kind of a (crappy) fan).
And, in fact, that's what this device does. It uses an array of 12 small rotating fans placed around its surface to push jets of air and move itself from place to place.
Yes, I know.
My point was that in principle, you could abuse reaction wheels to give you translation capability if you're moving through air.
Re: Japan's zero-gravity space drone sends first pictures from ISS
#64and no word on how it moves. even bbc is going downhill :(
Forgive the stupid question: what makes the use of reaction wheels and fans preferred over fans installed at different angles? Energy efficiency or fan reliability perhaps?
You can get really good stability and precision using reaction wheels.
Re: Japan's zero-gravity space drone sends first pictures from ISS
#65Earlier quoted context omitted.
It seems to be rotating via reaction wheels (via this[0]). I haven't yet figured out how it translates, though. EDIT: if you have gravity available, the video on that site illustrates a clever way to use those reaction wheels to move around by tumbling. EDIT2: "for maneuvering around in space there are twelve electric micro-fans or μFans"[1]. The SE thread has a screenshot of a video which shows the placement of thos…
The use of fans is disappointing; that means it can't go outside. My first thought when seeing it is that it'd be great for doing external inspections, and could even have its own private little airlock to get in and out. Maybe they could make a version with ionic thrusters, that stays outside all of the time. It could have a 'nest' where it parks and refuels when not in use.
I wouldn't want to be on the wrong end of a small particle accelerator and I wouldn't want any part of my spaceship in that position either.
Re: Japan's zero-gravity space drone sends first pictures from ISS
#66I can understand how it rotates, but how does it moves? as in going from one module to the next one?
Same way an airplane works - push against the air.
Re: Japan's zero-gravity space drone sends first pictures from ISS
#67NASA is working on a similar (but more capable and larger) robot right now, with plans to open-source all the code. I'm curious what the internals of JAXA's robot look like. That thing is pretty small.
Re: Japan's zero-gravity space drone sends first pictures from ISS
#68Earlier quoted context omitted.
though less technical, "movement" implies "momentum", no? In the person + bike system, the brake action would result in internal forces. I don't see how this system could translate.
Not sure about the movement-momentum question. Thinking about it, the bicycle would only rotate about the center unless it had something to react against, as was pointed out by others.
well, momentum is defined as the product of mass and velocity. movement implies velocity, and we are not talking about massless things here, so yes, movement implies momentum.
Re: Japan's zero-gravity space drone sends first pictures from ISS
#69Earlier quoted context omitted.
They work 8 hours a day including exercise? That seems bizarre to me. I know we don't want them burning out, etc., but if we're sending astronauts up there at great expense I'd think we'd want to ask them to put in a little more than 8 hour days. 16 hours a day plus weekends seems like a ridiculous amount of free time given that there's no commuting, family time (other than calls), yard work, social engagements, etc.
I think you might be grossly underestimating the psychological impact of spending 6 months inside a place the size of an apartment with no day or night cycle, a constant feeling of weightlessness, and no ability to go outside or feel things like wind or rain.
They're stuck inside there anyways. If it were me, I suspect I'd prefer to stay occupied. I'm not saying we should work them to the bone, but 16 hours a day plus weekends just seems like a lot of time to fill when there's limited options anyways.
BTW, I'm being down-voted above for expressing surprise at the claim the crew only works 8 hours daily including 2 hours exercise. But the example crew day shown in the following link suggests (by my reading) that it's more like 11 hours (7:30-7:30 with an hour of lunch):
https://www.quora.com/Whats-the-typical-daily-schedule-in-th...
Re: Japan's zero-gravity space drone sends first pictures from ISS
#70Earlier quoted context omitted.
They work 8 hours a day including exercise? That seems bizarre to me. I know we don't want them burning out, etc., but if we're sending astronauts up there at great expense I'd think we'd want to ask them to put in a little more than 8 hour days. 16 hours a day plus weekends seems like a ridiculous amount of free time given that there's no commuting, family time (other than calls), yard work, social engagements, etc.
I don't think they actually work just eight hours a day. There's a lot of maintenance work to do and it's not like there are many things to do on your free time. Although now that there's the full six-person crew, the schedules are probably less tight.
It sounds like you're agreeing with me...