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Perseverance Rover lands on Mars [video]

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Re: Perseverance Rover lands on Mars [video]

#261

Post by zokier »

kibwen wrote: post #145
nothis wrote: post #130

Earlier quoted context omitted.

Anyone know the bandwidth they're working with, at least roughly?

Here's a page with data about the Deep Space Network: https://mars.nasa.gov/msl/mission/communications/#data "The data rate direct-to-Earth [from Mars] varies from about 500 bits per second to 32,000 bits per second"

Clarification, that is for the old Curiosity rover. The page for Perseverance has some additional information

> 160/500 bits per second or faster to/from the Deep Space Network's 112-foot-diameter (34-meter-diameter) antennas or at 800/3000 bits per second or faster to/from the Deep Space Network's 230-foot-diameter (70 meter-diameter)

for high-gain antenna, and

> Approximately 10 bits per second or faster from the Deep Space Network's 112-foot-diameter (34-meter-diameter) antennas or approximately 30 bits per second or faster from the Deep Space Network's 230-foot-diameter (70-meter-diameter) antenna

for the low-gain antenna, which I believe the first two images were sent through

https://mars.nasa.gov/mars2020/spacecraft/rover/communicatio...

Re: Perseverance Rover lands on Mars [video]

#262

Post by Koshkin »

natosaichek wrote: post #217
kharak wrote: post #203

Earlier quoted context omitted.

Thank you for the explanation. That was highly interesting. Does anyone else know if the human eye does perceive color directly? Is this at all technically possible? And if yes, why aren't we doing it with cameras?

What do you mean by "directly"? Color is a human abstraction over the reception intensity of certain wavelengths of light.

What do you mean “abstraction”? The colors that I am seeing look very concrete to me. (Also, the “wavelength theory” of color perception does not explain why TV screens work.)

Re: Perseverance Rover lands on Mars [video]

#263

Post by fckthisguy »

spaetzleesser wrote: post #236
tectonic wrote: post #14

You can also watch an EDL visualization in your browser: https://eyes.nasa.gov/apps/mars2020/#/home And read about how it will use Terrain Relative Navigation to find a safe landing spot: https://www.jpl.nasa.gov/news/a-neil-armstrong-for-mars-land... Perseverance is phenomenally complex, its Sample Caching System alone contains 3,000+ parts and two robotic arms. So exited for all the sciencing this nuclear-powered,…

They should make km the default unit and not miles....

As another commenter said, NASA uses metric.

During the stream, you can hear the various teams giving measurements in metric, whilst the media gave coverage in imperial.

It's a pretty interesting video from that perspective, as you can hear the two "realities" being translated for the intended audience.

Re: Perseverance Rover lands on Mars [video]

#264

Post by fckthisguy »

Daho0n wrote: post #222
gfiorav wrote: post #197

Earlier quoted context omitted.

Waiting for the physicist in the room to point out: there is no such thing as simultaneity! :)

S/he already did. We just don't know yet.

You can just say "they".

(Not trying to be judgy. People just seem to forget about the gender neutral use of "they".)

Re: Perseverance Rover lands on Mars [video]

#266

Post by [deleted] »

WJW wrote: post #131
tectonic wrote: post #14

You can also watch an EDL visualization in your browser: https://eyes.nasa.gov/apps/mars2020/#/home And read about how it will use Terrain Relative Navigation to find a safe landing spot: https://www.jpl.nasa.gov/news/a-neil-armstrong-for-mars-land... Perseverance is phenomenally complex, its Sample Caching System alone contains 3,000+ parts and two robotic arms. So exited for all the sciencing this nuclear-powered,…

> is this what NASA calls 'weights'? Well no, the Cruise Mass Balance Devices are intended to Balance the Mass of the spaceship during Cruise conditions. That these Devices are single-part and constructed out of a single chunk of metal each should not be construed as merely being 'weights'. :)

[deleted]

Re: Perseverance Rover lands on Mars [video]

#267

Post by extropy »

kibwen wrote: post #145
nothis wrote: post #130

Earlier quoted context omitted.

Anyone know the bandwidth they're working with, at least roughly?

Here's a page with data about the Deep Space Network: https://mars.nasa.gov/msl/mission/communications/#data "The data rate direct-to-Earth [from Mars] varies from about 500 bits per second to 32,000 bits per second"

That's rover directly to earth, when reconnaissance orbiter is used to relay it's around 2 mbit to orbiter.

Re: Perseverance Rover lands on Mars [video]

#268

Post by Nekhrimah »

Daho0n wrote: post #210
marcinzm wrote: post #114

Earlier quoted context omitted.

The Space Shuttle was reusable (with massive refurbishing after each flight) but given that'd it cost significantly more than a non-reusable rocket per pound I think the point stands. SpaceX managed to make a financially viable reusable rocket.

They really didn't. SpaceX is not cheaper than the shuttle no matter how many times it gets repeated. That SpaceX fudges the numbers so it is hard to compare doesn't make it true. In reality SpaceX is more expensive than not only the shuttle but also their own projections. Here's a breakdown: https://youtu.be/4TxkE_oYrjU

> Here's a breakdown: https://youtu.be/4TxkE_oYrjU

I watched the first 90 seconds of this. On the cost of re-usability of a falcon 9 point, the figures are shown as from Wikipedia.

So 1) not a primary source. 2) fails to calculate the percentage correctly between $62m and $50m as "around 10%". It's almost 20% on those figures. 3) and most importantly, those numbers are the cost to the customer, not SpaceX's internal cost. As they have no current competition in rocket re-usability, they are able to recoup the R&D cost for developing this technology.

I don't think I'll bother watching the rest of the video.

Re: Perseverance Rover lands on Mars [video]

#269

Post by mulmen »

spaetzleesser wrote: post #236
tectonic wrote: post #14

You can also watch an EDL visualization in your browser: https://eyes.nasa.gov/apps/mars2020/#/home And read about how it will use Terrain Relative Navigation to find a safe landing spot: https://www.jpl.nasa.gov/news/a-neil-armstrong-for-mars-land... Perseverance is phenomenally complex, its Sample Caching System alone contains 3,000+ parts and two robotic arms. So exited for all the sciencing this nuclear-powered,…

They should make km the default unit and not miles....

Ever been on an airplane? Altitude was almost certainly measured in kilofeet.

As noted in other comments, NASA (like the rest of the United States [1]) does use the metric system.

But it doesn’t matter. Nothing about the metric system makes it uniquely suitable to landing on Mars. Or space travel in general. What matters is a consistent standard.

Internally NASA could use Armstrongs. Where 1 is the weight or height of Neil Armstrong at KSC on July 16, 1969 at 13:32:00 UTC. It doesn’t matter. As long as it is consistent.

[1]: https://en.m.wikipedia.org/wiki/Metrication_in_the_United_St...

Re: Perseverance Rover lands on Mars [video]

#270

Post by lathiat »

jamiek88 wrote: post #256
twic wrote: post #216

Earlier quoted context omitted.

> Cruise Mass Balance Devices They put those in to make the probe seem higher-quality. They got the idea from Beats headphones.

Just to set the record a bit straighter and ruin your joke, those pics of beats with weights were knockoff beats from the flea market not real.

Reporting on that: https://gizmodo.com/are-beats-headphones-really-designed-to-...
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