Mars Rover Landing - 3 DAYS LEFT

[Winston]

All of the content from the additional cameras included this time recording the 'chute deployment pointing upward and the landing looking downward will only be uplinked eventually if the rover lands successfully. They will not be live nor will be the audio from the microphone.

Mars Rover Landing - 3 DAYS LEFT



Nice comparison of Pathfinder rover Sojourner vs Perseverance:

Mars 2020 rover: How far we've come



The Sojourner computer specs in that video are slightly incorrect although it's correct about the CPU being the same type as in the Tandy 100. Only CPU main memory RAM was 64K:

A Description of the Rover Sojourner

https://mars.nasa.gov/MPF/rover/descrip.html
Control is provided by an integrated set of computing and power distribution electronics. The computer is an 80C85 rated at 100Kips which uses, in a 16Kbyte page swapping fashion, 176Kbytes of PROM and 576Kbytes of RAM. The computer performs I/O to some 70 sensor channels and services such devices as the cameras, modem, motors and experiment electronics.

It's so difficult to find any decent material on Sojourner that isn't behind a paywall. This one is a crappy OCR text scan from a document:

https://trs.jpl.nasa.gov/bitstream/handle/2014/22611/97-1122.pdf
At bootup or upon reset the computer begins execution from the radhard PROM. The programming stored in PROM loads programs into the radhard RAM from non-volatile RAM. Program execution proceeds from the RAM: As commands are executed, other programming in non-volatile RAM is required and then swapped into the RAM for execution. To prevent excessive thrashing, some programs are executed from non-volatile RAM.

Sojourner Picture and Video Files

https://mars.nasa.gov/MPF/rovercom/pix.html
Six wheels on the ground: NASA's Mars rovers

https://trs.jpl.nasa.gov/bitstream/handle/2014/45159/10-4139_A1b.pdf

 

[Marc_G]

I've had 3pm-5pm Thursday cleared on my calendar once touchdown time was published following launch.

Relieved it is a daytime landing; was up into the wee hours for Curiosity's landing.

The pucker factor on these complex chute/thruster/skycrane landings is just incredible.

 

[Hobie1dog]

We only get to see it if it is successful

 

[Marc_G]

Well, I will be following it down until it lands or until we lose the signal. I like how "recent" landings have incorporated more low bandwidth telemetry tones to allow the engineers to know the status continually so that if it does fail, there's a good chance of understanding what happened.

Seven minutes of terror, indeed!

 

[Winston]

Pending live videos, some today:

Engineering & Tech Overview – NASA Perseverance Mars Rover



Science Overview – NASA Perseverance Mars Rover



Searching for Life on Mars - NASA Press Conference



NASA Previews Perseverance Mars Rover Landing



Mission Control Live: NASA Lands Perseverance Mars Rover (360 video)

 

[Winston]

Discussion of the tech that most concerns me (Terrain Relative Navigation - TRN) starts 23:42 and a great question on that is at 1:03:52. His hover time question was never answered. What is very interesting is that it is the only question they seemed to be annoyed about indicating to me that that's a worry item for them, too. TRN enables the landing in a very hazardous area and if it doesn't work as planned... As the questioner states, it's considered a "tech demonstrator" system just like the helicopter, but unlike the helicopter it is mission critical.

 

[Marc_G]

Festivities continue with the Perseverance edition Mars donut!

https://www.cnn.com/2021/02/16/world/krispy-kreme-mars-doughnut-scn-trnd/index.html

 

[pollux]

I've had 3pm-5pm Wednesday cleared on my calendar once touchdown time was published following launch.

What happens on Wednesday? What am I missing?

 

[Marc_G]

What happens on Wednesday? What am I missing?

The Perseverance Rover touches down on Thursday (sorry, Wednesday was a typo) at 3:55 pm eastern time. At least, that's the plan. One way or another it will be on Mars then.

 

[Marc_G]

Nice article here on the various orbiters that will monitor the landing attempt:

https://www.space.com/perseverance-mars-rover-landing-orbiters-watching-from-space

 

[Marc_G]

My palms are all sweaty already; I'm having some landing anxiety flashes.

I almost had to pick up my son at 3:45 today at school due to iStep testing, but it got rescheduled again due to weather issues. I had prepped him that I would be in the parking lot with my computer up tethered to my phone, and he could expect to sit in the car with me until it was over.

 

[Marc_G]

Roku channel feed sucks; seems about 30 seconds behind realtime nasa.gov feed. Switched my TV to the computer feed.

 

[Winston]

As I watch with the 11 minute signal delay from Mars, I realize it has already either landed or crashed. Weird to think of that.

 

[Marc_G]

yup

 

[Alan R]

As I watch with the 11 minute signal delay from Mars, I realize it has already either landed or crashed. Weird to think of that.

this was my question as i'm watching...(5 min away) ... it's already landed or crashed right?
Is it only 11 min? I thought it was closer to 20

 

[David J]

Touchdown!

 

[Sooner Boomer]

AMAZING!

 

[Marc_G]

this was my question as i'm watching...(5 min away) ... it's already landed or crashed right?.
Is it only 11 min? I thought it was closer to 20

Distance in light minutes to Mars ranges from 3 at the closest approach to about 20 when it's on the other side of the sun from us

 

[Alan R]

Distance in light minutes to Mars ranges from 3 at the closest approach to about 20 when it's on the other side of the sun from us

never thought it would be that large of a range. But i can picture it in my head now. wow. Thanks for the update.

 

[Winston]

Incredibly impressive accomplishment. SO many things had to go perfectly. 158 pyro events during EDL.

I was listening in on the post-landing JPL "clean" feed [no commentary, just tech comm] on YouTube while doing other things and was hearing interesting stuff and then all of the various JPL feeds on YouTube died. Crap...

That feed:

 

[Winston]

Post-landing briefing. Listed as starting at 5:30 EST, but on the NASA page they wisely say "No Earlier Than 5:30."

 

[Marc_G]

Ah, NET 5:30. I was starting to get concerned. Thanks.

 

[NOLA_BAR]

I wish there was a way they could get a camera to the surface before the landing to video the sky crane maneuver.

 

[Winston]

Also:

Friday, Feb. 19 at 1 p.m. EST (1800 GMT): Perseverance rover update.
Monday, Feb. 22 at 2 p.m. EST (1900 GMT): Perseverance rover update.

 

[Marc_G]

Briefing started. I want one of those Perserverence logo masks!

 

[Winston]

Made these up from various video screen captures and added annotations:

Based upon the assumption of hitting the center of the ellipse:

 

[MClark]

From the first pictures I think it landed at Black Rock.

M

 

[Alan R]

seems odd they would have the sharp edge of a lava flow running through the center of the landing site. what if it hit that edge? why not move the center of the landing circle out a bit from that cliff
confirmed location looks like a nice spot that should have been dead center

 

[Hobie1dog]

128 Million miles from Earth to Mars and we have communication with a craft we made and guided there. That folks is why there are non-believers that we can do it. But my best friend and I were talking last night and with 8.2 Billion people on the planet, 8.19 Billion walk around and conduct themselves like they have a 8th grade education. Only a few select group of people have scientific backgrounds and keep building the knowledge base very, very slowly. Technology will keep advancing, people......not so much. Congrats to all the people who made this happen.

 

[NOLA_BAR]

seems odd they would have the sharp edge of a lava flow running through the center of the landing site. what if it hit that edge? why not move the center of the landing circle out a bit from that cliff
confirmed location looks like a nice spot that should have been dead center

What you are looking at is actually sediments from a river delta. It formed from a breach in the crater to the upper left of the image. This is the main, or one of the main mission targets, and is thought to have formed about 3.5 billion years ago.

But, yes it does look kinda risky for a landing site. I’ve read that they are much more accurate at landing now, using an onboard terrain navigation system. Curiosity could not have landed here, the landing ellipse was too large.