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Perseverance Launch & Cruise
pioneer
post Aug 14 2020, 01:08 AM
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QUOTE (nprev @ Aug 9 2020, 06:28 AM) *
Per this page, each sample is max 15g & there are a max of 30 samples, so 450g...just shy of 1 pound in imperial units (454g).


Thanks
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Explorer1
post Aug 14 2020, 01:38 AM
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QUOTE (pioneer @ Aug 13 2020, 08:05 PM) *
Does anyone know how Ingenuity will avoid having its landing legs land on a large rock and tilting it over? From what I understand, it doesn't have a hazard detection system. I'm guessing it will somehow know where it lifted off from and return there after the flight?


Pages 16 and 17 of this 2018 paper give a good description of the plan:
QUOTE
After landing, the rover will begin traversing to the closest ROI. On the way to the ROI, using orbital data, the rover could be directed to areas that likely meet the requirements for deploying the helicopter and flying the technology demonstration sorties. These areas would have to have low slopes and sufficient surface texture for accurate tracking by the demonstrator’s navigation filter during flight and few rocks higher than 5 cm to interfere with its landing. The rover would need to image the area being considered at higher resolution than from orbit using stereo rover Navigation camera images to determine if it meets the requirements.
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atomoid
post Aug 14 2020, 10:43 PM
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With tip-prevention by careful reconnaissance to plan avoidance of such features in the flight plan seems effective enough given the other risks, in the NASA article it also states "If Ingenuity survives the cold Martian nights during its preflight checkout, the team will proceed with testing" a choice of words that didn't exactly fill me with confidence, but from the paper linked by Explorer1 shows in page 15-16 section 'H' seems the batteries should have more than adequate capacity to provide the 21Wh needed to keep above -15C at night, but does anyone know if the CO2 insulation was ever replaced by aerogel?
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pioneer
post Aug 14 2020, 11:14 PM
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TCM-1 was supposed to be today, but I heard it was delayed according to Reddit due to the accuracy of the launch. I haven't heard anything official from JPL or NASA though.
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Marvin
post Aug 15 2020, 03:19 AM
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TCM-1 was completed today:

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My first planned Trajectory Correction Maneuver was a success. I do TCMs on my journey to stay on target for a Feb. 18, 2021 date with Mars. I left Earth over 2 weeks ago and already put on 27+ million miles. Only ~265 million more to go!


https://twitter.com/NASAPersevere/status/1294450300095471616
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pioneer
post Nov 12 2020, 10:43 PM
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Perseverance is now fewer than 100 days away from landing on Mars.
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Explorer1
post Nov 19 2020, 12:23 AM
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In addition to an EDL microphone recording of the heating system, one of the hazcams took some images during the cruise of some insulation and a cable:

https://www.jpl.nasa.gov/news/news.php?feature=7789

I am wondering about the lighting though: is that sunlight coming through the aeroshell, or something internal?
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antipode
post Nov 19 2020, 02:38 AM
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I thought these cruise shots were illuminated by an LED, but I could be wrong.

P
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rlorenz
post Nov 24 2020, 05:21 PM
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QUOTE (Explorer1 @ Nov 18 2020, 07:23 PM) *
In addition to an EDL microphone recording of the heating system


This may be of interest re: sound propagation in the Mars atmosphere
http://www-mars.lmd.jussieu.fr/granada2017...granada2017.pdf
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djellison
post Nov 24 2020, 07:20 PM
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QUOTE (antipode @ Nov 18 2020, 06:38 PM) *
I thought these cruise shots were illuminated by an LED, but I could be wrong.

P


There's no LED illumination out the back of the rover. That illumination is coming through gaps in the backshell
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vjkane
post Nov 25 2020, 12:50 AM
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QUOTE (djellison @ Nov 24 2020, 11:20 AM) *
There's no LED illumination out the back of the rover. That illumination is coming through gaps in the backshell

Obviously this isn't true, but I would have thought that gaps would allow super heated gasses to enter the backshell during entry.


--------------------
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rlorenz
post Nov 25 2020, 04:04 AM
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QUOTE (vjkane @ Nov 24 2020, 07:50 PM) *
Obviously this isn't true, but I would have thought that gaps would allow super heated gasses to enter the backshell during entry.


It's perhaps surprising, but there is a vent hole in the backshell - you have to let the air escape during launch to avoid a pressure differential that could cause structural failure. The same hole (the ~30cm dark circle you can see on backshell images, but there is some sort of wire mesh/filter, so the effective area is only 600cm2 or so) allows the aeroshell to repressurize during entry/descent, but this is slower. Attention is paid to avoid sensitive items being exposed to that repressurization flow, but it is relatively slow (effectively it just sips at the wake, it isnt exposed to the dynamic pressure on the heat shield).

I managed to put together some info on this sort of venting in a recent paper (email me if you can't access)
https://arc.aiaa.org/doi/abs/10.2514/1.A34861
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