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Mars Rover Perseverance Discussion Thread


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For anyone with access to a 3D printer who would like to print a terrain model for themselves to go along with the Perseverance Rover's arrival at Mars (whether it be a fireball, a new crater, or a smooth landing...I'm looking forward to the event)...

We have made some printable models using the NASA Mars Trek ...& anyone can also pretty easily make their own custom models as well either directly in the NASA Trek or with a DEM & QGIS...

(I also wrote & included a short 'story' about the Mars atmosphere: sunset & cloud colors and how that relates to space garlic bread, the U2 spy plane, etc...with wording geared to be mostly understandable by younger students, while the links are more detailed & advanced with some nice images/fun videos) 

https://www.thingiverse.com/thing:4747950

Mars Perseverance Rover Target Landing Area 3D printable Terrain Models
bmoT8iK.jpg

Enjoy!

Edited by AloE
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6 hours ago, AloE said:

For anyone with access to a 3D printer who would like to print a terrain model for themselves to go along with the Perseverance Rover's arrival at Mars (whether it be a fireball, a new crater, or a smooth landing...I'm looking forward to the event)...

You know, I think I will print one in red.

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41 minutes ago, StrandedonEarth said:

Blazes straight into the atmosphere at interplanetary transfer velocity

I mean, if they actually enter orbit first then releases landers/rovers that'd actually take more effort than direct landing. It is less dangerous but it's also more propellant.

That being said, Tianwen-1 is trying to do exactly that, but again only because they're taking it safe. Other agencies had done similar before, including NASA back in 1975.

Edited by YNM
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1 hour ago, StrandedonEarth said:

 

I actually came here to ask about this - is the transfer speed lower than the orbital speed?  

 

Why take the risk?  Lower fuel costs? 

 

Edit: oh, and you know we're getting cocky when NASA says 'hold mah beer and watch dis' 

Edited by JoeSchmuckatelli
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1 hour ago, YNM said:

I mean, if they actually enter orbit first then releases landers/rovers that'd actually take more effort than direct landing. It is less dangerous but it's also more propellant.

That being said, Tianwen-1 is trying to do exactly that, but again only because they're taking it safe. Other agencies had done similar before, including NASA back in 1975.

It certainly does help to have an orbiter relaying data for landers, but NASA already has three of those active

 

3 minutes ago, JoeSchmuckatelli said:

I actually came here to ask about this - is the transfer speed lower than the orbital speed?  

 

Why take the risk?  Lower fuel costs? 

.Well, according to this SS subway map I googled, it's 1440m/s for LMO insertion, without any aerobraking. That's a heap'o'propellant. Add on any deorbit burn and possible release mechanism (for orbiter/lander combo). Much less mass to just plow in. In fact, most combos IIRC separate on approach and have the lander enter direct while the orbiter does a capture burn. Again.less props needed, compared to a trivia amount of extra shielding needed to handle the extra speed.

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Just now, StrandedonEarth said:

It certainly does help to have an orbiter relaying data for landers, but NASA already has three of those active

Good point, given they're not exactly in good terms with the major presence there.

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1 hour ago, JoeSchmuckatelli said:

I actually came here to ask about this - is the transfer speed lower than the orbital speed?  

The transfer speed from a solar orbit is faster than orbital speed - but by aerobraking from the Sun you can lose all your velocity all the way down to the surface with just the atmosphere. Entering orbit first requires firing engines, but it helps reduce the intensity of atmospheric entry.

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2 hours ago, cubinator said:

The transfer speed from a solar orbit is faster than orbital speed - but by aerobraking from the Sun you can lose all your velocity all the way down to the surface with just the atmosphere. Entering orbit first requires firing engines, but it helps reduce the intensity of atmospheric entry.

Interestingly, Perseverance's atmospheric entry speed, direct from its transfer orbit, will be on the order of 5 km/s, which is substantially less than atmospheric entry speed from LEO. Of course that doesn't mean Mars atmospheric entry is easy...

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I'm not just here to be pedantic, though...

Does anyone know how they're acquiring the video data from the cameras on the backshell and sky crane? I understand that the video will be stored on Perseverance until they have the bandwidth to downlink it to Earth some weeks or months after landing, but they'd obviously need to stream the video data directly from those cameras to Perseverance during the landing. The backshell and sky crane won't be around anymore once Perseverance is on the surface. 

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On 2/11/2021 at 3:15 PM, PakledHostage said:

Interestingly, Perseverance's atmospheric entry speed, direct from its transfer orbit, will be on the order of 5 km/s, which is substantially less than atmospheric entry speed from LEO. Of course that doesn't mean Mars atmospheric entry is easy...

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I'm not just here to be pedantic, though...

Does anyone know how they're acquiring the video data from the cameras on the backshell and sky crane? I understand that the video will be stored on Perseverance until they have the bandwidth to downlink it to Earth some weeks or months after landing, but they'd obviously need to stream the video data directly from those cameras to Perseverance during the landing. The backshell and sky crane won't be around anymore once Perseverance is on the surface. 

This paper describes the various camera systems on Perseverance in great detail. The cameras being used during the EDL stage are all wired into a central data storage unit on the rover via USB & the wires will be cut as each stage separates (ending communication with that camera). The down looking camera on the skycrane will work right up until the rover touches down & the rover tether is cut, so we should get good pictures of what the sky crane landing process really looks like. I guess the risk of interference during landing ruled out using a wireless link for any of these cameras, although if the Mars copter onboard successfully flies it will send images & other data back to the rover via radio.

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I wonder if anyone ever considered landing the sky-crane once it releases the rover and flies some distance away? If it can hover with the lander hanging below, it should have both thrust and control to land itself, right?

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2 minutes ago, Scotius said:

I wonder if anyone ever considered landing the sky-crane once it releases the rover and flies some distance away? If it can hover with the lander hanging below, it should have both thrust and control to land itself, right?

I guess without any instruments on the sky-crane it would be rather moot, and any instruments (and comms you need to get the data from them to Earth!) you might add would be extra mass you would have to give up on the rover instead. You don't need to reserve as much fuel for a ballistic hop away from the rover than you would need for a smooth landing either. So I think any such consideration probably quickly converges on "better value to put every ounce we can on the rover."

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I wouldn't say it would be moot. Sooner or later we will send astronauts to land on Mars. For crewed spaceship sky-crane, parachutes and airbags aren't really an option. Gathering experience with powered landings on Mars, using hardware that completed its main mission and is now expendable would be similar to the way SpaceX used to perfect the recovery of Falcon 9 boosters.

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1 minute ago, Scotius said:

I wouldn't say it would be moot. Sooner or later we will send astronauts to land on Mars. For crewed spaceship sky-crane, parachutes and airbags aren't really an option. Gathering experience with powered landings on Mars, using hardware that completed its main mission and is now expendable would be similar to the way SpaceX used to perfect the recovery of Falcon 9 boosters.

Possibly, but I think there’s limited value in such an endeavour when it lacks the numerous attempts SpaceX could give the booster landing. I get the impression they learned mostly from the changes they made between attempts, and you can’t quickly make changes and try again on Mars. I think you’d really only get a lot of good data if you landed successfully.

I’d love to be proven wrong, though! Maybe that Mars sample return mission can give it a shot?

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1 hour ago, Scotius said:

Sooner or later we will send astronauts to land on Mars.

Yes, it follows the Mobiles' dropship program.
It flies away to not unmask the landed rover before the Martians can react.

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1 hour ago, RyanRising said:

Possibly, but I think there’s limited value in such an endeavour when it lacks the numerous attempts SpaceX could give the booster landing. I get the impression they learned mostly from the changes they made between attempts, and you can’t quickly make changes and try again on Mars. I think you’d really only get a lot of good data if you landed successfully.

I’d love to be proven wrong, though! Maybe that Mars sample return mission can give it a shot?

The actual powered landing on mars can probably be treated as in vacuum. 
Dust in the air from the landing might be an complication , its why they use an sky-crane after all. 

Now  landing the sky-crane has some issues, one is fuel or if the reserves is large enough.  They want the skycrane some distance from the lander then it crash. Safe distance will be shorter if it land but it might well mess up an landing and landing require more dV and fuel.
We have also landed many times under power on mars so its not that much to learn. 
New on this mission is the accuracy they assume for the landing as they have an systems to improve accuracy both during reentry and final approach. 
 

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