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Hayabusa 2 rovers send new images from Ryugu surface

bbc.co.uk

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Re: Hayabusa 2 rovers send new images from Ryugu surface

#41

Post by withinrafael »

rwmj wrote: post #20
21 wrote: post #18

I'm sure it's a very complicated problem, but I would have expected a 5 year old rover to have a better camera. I am a bit shocked at the potatoness of it.

I'm pretty sure it's not a poor camera because they couldn't afford it. It'll be because of weight considerations. If you have a higher resolution camera, everything has to be bigger and heavier - larger camera, more local storage, more processing power, bigger antenna (these have to be sent using lossless compression for science), etc. Each robot has a mass of 1.1 kg, lighter than my laptop - and it has to do other…

I suspect that too, but am looking for data to support this. We have tiny miracles in our cell phones today, are they really any heavier than what's on that vehicle? (I understand a cell phone camera isn't Space Ready™.) Does it require, perhaps, additional hardware that wouldn't be needed otherwise with today's on-board solution? And what's up with the severe lens distortion?

Cool topic I hope to dig into a bit to get those answers.

Re: Hayabusa 2 rovers send new images from Ryugu surface

#42

Post by ceejayoz »

yazr wrote: post #34

How does one "land" on an asteroid which is spinning too fast ? Is it at all possible to match the spin of a smallish android from orbit ?

Make a sturdy lander and just crash into it.

https://spaceflightnow.com/2018/06/20/asteroid-ryugu-reveale... says Ryugu only rotates once every 7.6 hours.

Re: Hayabusa 2 rovers send new images from Ryugu surface

#43

Post by criddell »

FriedPickles wrote: post #32
criddell wrote: post #31

Earlier quoted context omitted.

You don't happen to know of an animation showing the system in action, do you?

https://youtu.be/b9fITBmQt1Y?t=4m25s I recommend watching the whole video.

That was perfect. Thank you!

Re: Hayabusa 2 rovers send new images from Ryugu surface

#44

Post by Rebelgecko »

withinrafael wrote: post #41
rwmj wrote: post #20

Earlier quoted context omitted.

I'm pretty sure it's not a poor camera because they couldn't afford it. It'll be because of weight considerations. If you have a higher resolution camera, everything has to be bigger and heavier - larger camera, more local storage, more processing power, bigger antenna (these have to be sent using lossless compression for science), etc. Each robot has a mass of 1.1 kg, lighter than my laptop - and it has to do other…

I suspect that too, but am looking for data to support this. We have tiny miracles in our cell phones today, are they really any heavier than what's on that vehicle? (I understand a cell phone camera isn't Space Ready™.) Does it require, perhaps, additional hardware that wouldn't be needed otherwise with today's on-board solution? And what's up with the severe lens distortion? Cool topic I hope to dig into a bit to g…

A few factors I can think of:

The rovers launched in 2014, and they were designed well before that. I wouldn't be surprised if the camera hardware was decided on in 2010

A normal camera in space is going to have problems. I'm not any sort of camera expert, but I can imagine there's a _lot_ of electronics in one. There's the sensor. That sensor may be hooked up to an analog to digital converter, which might be hooked up to a processor that converts whatever the sensor reads into a compressed image. Someone who is familiar with how cameras work can probably think of a dozen bits I'm missing :)

All of those bits of silicon are going to get bombarded with radiation, so they need to be radiation hardened. Smaller transistors are especially susceptible to radiation, so your radiation hardened chips are going to be bigger, more power hungry, and generally not as good as more up to date ones. From looking around online, it looks like the best rad-hard cameras today are only a couple megapixels.

I'm not sure about this case, but often times cameras not a priority for a mission. They're great for generating PR and excitement, but in terms of scientific value there's lots of other instruments that may have higher priority (both in terms of the design, and in terms of available bandwidth for returning data). If the cameras are just there to make sure the rover doesn't crash into something, they're probably using a wide angle lens which helps with navigation but can cause distortions.

Re: Hayabusa 2 rovers send new images from Ryugu surface

#45

Post by tmd »

withinrafael wrote: post #41
rwmj wrote: post #20

Earlier quoted context omitted.

I'm pretty sure it's not a poor camera because they couldn't afford it. It'll be because of weight considerations. If you have a higher resolution camera, everything has to be bigger and heavier - larger camera, more local storage, more processing power, bigger antenna (these have to be sent using lossless compression for science), etc. Each robot has a mass of 1.1 kg, lighter than my laptop - and it has to do other…

I suspect that too, but am looking for data to support this. We have tiny miracles in our cell phones today, are they really any heavier than what's on that vehicle? (I understand a cell phone camera isn't Space Ready™.) Does it require, perhaps, additional hardware that wouldn't be needed otherwise with today's on-board solution? And what's up with the severe lens distortion? Cool topic I hope to dig into a bit to g…

Also not an expert on the topic but here are some examples of space-ready cameras with pictures and specs: http://www.msss.com/space-cameras/

Obviously radiation, extreme temperatures, vibration, and vacuum are at least some of the problems. They explicitly state that lens have no moving parts, I’m not sure why that is an issue and how can they focus without moving parts - maybe they’re just permanently focused on infinity and hence close objects are blurrier?

Lens distortion might be just normal with uncorrected very wide angle lens which you want to make framing/steering easier. Otherwise you might need a separate camera just to help you aim the first one.

Re: Hayabusa 2 rovers send new images from Ryugu surface

#46

Post by 24gttghh »

maxxxxx wrote: post #15
z2 wrote: post #9

Earlier quoted context omitted.

Consider literal competitions--it was similarly appalling to watch recent Olympics in the US. 95% or more of the coverage was of Americans winning. If a particular day had fewer wins, they would replay earlier footage rather than dare show any other country succeeding at non-American dominant areas. One saving grace is that the NBC app had all the footage they didn't deem worthy of broadcasting.

I can't watch the Olympics on US TV. Hours of stories about the upbringing of the US athletes interviewing moms and grandparents. Then a little actual sport if you are lucky. And certainly nothing where there isn't a US athlete/team at the front. It's unbearable.

In Maine we get the French-Language version of CBC, and they had near-constant coverage of more than just Canada. Even though I barely understand more than a few dozen words in French, it was better than watching NBC.

Re: Hayabusa 2 rovers send new images from Ryugu surface

#48

Post by tychomaz »

yazr wrote: post #34

How does one "land" on an asteroid which is spinning too fast ? Is it at all possible to match the spin of a smallish android from orbit ?

They have an open websocket to an Asteroid Landing five-layer Neural Network. The lander sends images back in real time and the earth-borne NN sends it telemetry adjustments in BSON.

Re: Hayabusa 2 rovers send new images from Ryugu surface

#49

Post by tychomaz »

joering2 wrote: post #2

Just came back from Europe. Everyone knows about this and all media reported on it. Surprisingly so little is said in American media. Its not new that Americans do not like other nations succeed in space! If these were US-based rovers, each network will give it 10 minutes cover. Same sad story about Chinese Moon landing. Most American friends laughed at me when I told them China landed rover on moon. Some even questi…

The Chinese moon CGI looked totally real.

Re: Hayabusa 2 rovers send new images from Ryugu surface

#50

Post by maxxxxx »

mc32 wrote: post #35
sandworm101 wrote: post #28

Earlier quoted context omitted.

Movement along the surface via friction (wheels, crawling, snaking etc) is not considered feasible. The surface is probably too loose to provide much traction, but more importantly the low gravity means the vehicle will certainly become caked in dust very quickly. Hopping means you don't disturb the surface, and if you do you probably fly clear of the resulting dust cloud.

Makes sense. Now that yoo bring up dust, how does erosion occur in space, or how would dust form other than perhaps through temperature fluctuations?

I am not an expert but I suppose it gets bombarded by a lot small particles all the time. Over a few million/billion years that adds up.
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