Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Hayabusa 2 rovers send new images from Ryugu surface

bbc.co.uk

Post reply on HN
Print view View original

21–30 of 60 posts

Re: Hayabusa 2 rovers send new images from Ryugu surface

#21

Post by cheeko1234 »

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.

Hayabusa2 carries multiple science payloads for remote sensing, sampling, and four small rovers that will investigate the asteroid surface by hopping and then on top of all that it will bring back samples in 2020!

All of that for less than $150 million! From a research data point of view, even having a color camera was overkill. Reminds me of Carl Sagan having to convince NASA to take the pale blue dot picture since it doesn’t have any significant value in the field of astronomy.

Re: Hayabusa 2 rovers send new images from Ryugu surface

#22

Post by mc32 »

cheeko1234 wrote: post #19

"Gravity on the surface of Ryugu is very weak, so a rover propelled by normal wheels or crawlers would float upwards as soon as it started to move," officials with the Japan Aerospace Exploration Agency (JAXA) wrote in a description of MINERVA-II1A and MINERVA-II1B. So, the robots — each of which measures 7 inches wide by 2.8 inches tall (18 by 7 centimeters) and weighs 2.4 lbs. (1.1 kilograms) — hop instead. They do…

Wonder if they could use some sort of rather slow mechanical deformation to provide movement with pump mechanisms. I guess that still would rely on significant gravity or other anchoring ti avoid slippage.

Re: Hayabusa 2 rovers send new images from Ryugu surface

#23

Post by cheeko1234 »

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…

Yup, am surprised at how many people at NASA have no clue this is going on. I expected at least a retweet or a mention from NASA.

Re: Hayabusa 2 rovers send new images from Ryugu surface

#24

Post by GlenTheMachine »

mc32 wrote: post #22
cheeko1234 wrote: post #19

"Gravity on the surface of Ryugu is very weak, so a rover propelled by normal wheels or crawlers would float upwards as soon as it started to move," officials with the Japan Aerospace Exploration Agency (JAXA) wrote in a description of MINERVA-II1A and MINERVA-II1B. So, the robots — each of which measures 7 inches wide by 2.8 inches tall (18 by 7 centimeters) and weighs 2.4 lbs. (1.1 kilograms) — hop instead. They do…

Wonder if they could use some sort of rather slow mechanical deformation to provide movement with pump mechanisms. I guess that still would rely on significant gravity or other anchoring ti avoid slippage.

Problem with that is you're relying on the surface properties of the material you're pushing against. If it's too soft, you get no motion. If it's too hard you get too much. The nice thing about using internal reaction wheels is that the torque you get is entirely independent of the surface you're resting on.

Re: Hayabusa 2 rovers send new images from Ryugu surface

#25

Post by arkh »

cheeko1234 wrote: post #21
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.

Hayabusa2 carries multiple science payloads for remote sensing, sampling, and four small rovers that will investigate the asteroid surface by hopping and then on top of all that it will bring back samples in 2020! All of that for less than $150 million! From a research data point of view, even having a color camera was overkill. Reminds me of Carl Sagan having to convince NASA to take the pale blue dot picture since…

> since it doesn’t have any significant value in the field of astronomy.

PR has some value: more people will want to try and join the field and more funding could be secured.

Re: Hayabusa 2 rovers send new images from Ryugu surface

#26

Post by mc32 »

GlenTheMachine wrote: post #24
mc32 wrote: post #22

Earlier quoted context omitted.

Wonder if they could use some sort of rather slow mechanical deformation to provide movement with pump mechanisms. I guess that still would rely on significant gravity or other anchoring ti avoid slippage.

Problem with that is you're relying on the surface properties of the material you're pushing against. If it's too soft, you get no motion. If it's too hard you get too much. The nice thing about using internal reaction wheels is that the torque you get is entirely independent of the surface you're resting on.

Oh those are very observations. Thanks for pointung them out.

Re: Hayabusa 2 rovers send new images from Ryugu surface

#27

Post by cheeko1234 »

arkh wrote: post #25
cheeko1234 wrote: post #21

Earlier quoted context omitted.

Hayabusa2 carries multiple science payloads for remote sensing, sampling, and four small rovers that will investigate the asteroid surface by hopping and then on top of all that it will bring back samples in 2020! All of that for less than $150 million! From a research data point of view, even having a color camera was overkill. Reminds me of Carl Sagan having to convince NASA to take the pale blue dot picture since…

> since it doesn’t have any significant value in the field of astronomy. PR has some value: more people will want to try and join the field and more funding could be secured.

NASA is not allowed PR as a federal agency. Imagine how far ads, sponsoring games/events, etc, would get NASA in terms of PR. Compare that to the military:

https://www.cheatsheet.com/money-career/amount-money-militar...

https://taskandpurpose.com/us-military-combat-trainer-kick-a...

Not only that, NASA's education department was as close to PR as we had and...

https://www.forbes.com/sites/startswithabang/2017/05/25/trum...

Re: Hayabusa 2 rovers send new images from Ryugu surface

#28

Post by sandworm101 »

mc32 wrote: post #22
cheeko1234 wrote: post #19

"Gravity on the surface of Ryugu is very weak, so a rover propelled by normal wheels or crawlers would float upwards as soon as it started to move," officials with the Japan Aerospace Exploration Agency (JAXA) wrote in a description of MINERVA-II1A and MINERVA-II1B. So, the robots — each of which measures 7 inches wide by 2.8 inches tall (18 by 7 centimeters) and weighs 2.4 lbs. (1.1 kilograms) — hop instead. They do…

Wonder if they could use some sort of rather slow mechanical deformation to provide movement with pump mechanisms. I guess that still would rely on significant gravity or other anchoring ti avoid slippage.

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.

Re: Hayabusa 2 rovers send new images from Ryugu surface

#29

Post by magicnubs »

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…

And the things only weigh 2 pounds. All added weight has to count on these.
Post reply on HN