MSL Approach Phase Options

[Syrinx]

we're talking about delayed return of the full EDL data set as the worst-case scenario in this situation, correct?

Not sure what you mean by "full data set" but Theisinger said the EDL pics would be stored and beamed back to Earth from the ground up, meaning LIFO style. The first EDL pics beamed back will be the ones taken closest to the ground and it would take 2-3 days to get all the pics.

[djellison]

Oh - the MARDI dataset is 1600 x 1200 x approx 500 images and will take several weeks to download in full. A thumbnail preview and a few full resolution frames will be available in a couple of sols - but it'll take several weeks. Pete certainly didn't say it would be take 2-3 days to get 'all the pics'

What nprev is talking about is the live 8kbps telemetry that Odyssey was to bent-pipe relay straight to the ground. If ODY is not in place, this will now not be on the ground until MRO dumps it, which will take about 4-5 hours. it wont be lost, we'll just get it later.

We'll also probably have an MODY pass at L+2hrs or so anyway.

[Lightning]

This means in case ODY can not be present at the right time, there is no backup to support MRO to get the data ?
And it then should be impossible to know what has happenned during EDL until 4 hours after landing ?

[djellison]

There would be DTE tones until the Earth sets ( after chute deploy ) and MRO relay later. That would be it.

We would probably see an ODY pass at landing +2hrs that would tell us everything is fine. Infact, we'd get that data back before the 8kbps data transmitted during EDL.

[SFJCody]

You know I can't tell you how much fun it is to come by here (I wish I had more time!!!). I get a huge kick from the thoughtful discussions of risk, and the fun walks through memory lane (like the link that SFJCody left on Post#169 to a 1997 bulletin board about the weirdness of Pathfinder's landing system and even a discussion about my old web page on EDL I created back then - what a hoot!)

Awesome to know, thanks! I just recently noticed that someone has uploaded CNN's coverage of the Pathfinder landing to youtube.

http://www.youtube.com/watch?v=zUaalbRC7KA

http://www.youtube.com/watch?v=7Au-S-tjyiU

[MarsEngineer]

Awesome to know, thanks! I just recently noticed that someone has uploaded CNN's coverage of the Pathfinder landing to youtube.

http://www.youtube.com/watch?v=zUaalbRC7KA

http://www.youtube.com/watch?v=7Au-S-tjyiU

Thank you SFJCody! You made my day. I had never seen the CNN coverage of Pathfinder coverage - at least if I did, I do not recall seeing it. (Yikes! I sounded like a DJ! But I am relieved to see that I have not aged a day! Not). There were moments that I had long forgotten. Those were happy moments. With a little luck we will have another one of those highly addicting moments.


I just spent the bulk of the day discussing MSL contingency procedures we have been developing for what we would do if we lost the signal(s) during EDL and immediately thereafter (of course we are considering ODY's targeting situation that Pete talked about - but I am not concerned by it). We have generic contingencies for the rover, but we needed a special one for the EDL - Sol 0 day. There are a lot of nerve-wracking ways for the signals to cease flowing and yet still allow us to recover the rover later on. So spent half the day reviewing and refining the plan.

It is amazing how much time we spend on the "negative" (i.e. things that can go wrong). It can easily get us down, but we have to do this in order to find and "mitigate" all of the risks that we face. We do this so that we can get that rush when everything works right and pages of new science text books flow down to us. Years of work trying to find all of the ways it won't work only to have what works left over.

-Rob

Comments are those of the author and do not represent the views of NASA/JPL/Caltech.

[jmknapp]

There were moments that I had long forgotten. Those were happy moments.

I watched that too--it was hard to miss your smile after talking about all the pyrotechnics that went off on the 4th of July:



It was an amazing thing--if I recall correctly I was at someone's house for a party and the TV was on around midnight or the wee hours (ET), showing (practically) live pictures from Mars--mindblowing.

[atomoid]

Just for clarity's sake, we're talking about delayed return of the full EDL data set as the worst-case scenario in this situation, correct? ...

...but it sounds like MSL has to transmit after touchdown in order to send its EDL after ODY comes into view, so i'll have to keep chewing my fingernails over worst case scenario being EDL failure and total loss of data with no chance to analyze and learn... so after fingernails gone, proceed to toenails.. no?

[brellis]

Wouldn't some limited direct transmit get recorded from Earth?

[djellison]

...but it sounds like MSL has to transmit after touchdown in order to send its EDL after ODY comes into view, so i'll have to keep chewing my fingernails over worst case scenario being EDL failure and total loss of data with no chance to analyze and learn... so after fingernails gone, proceed to toenails.. no?

No. MRO will still be in place to listen to and record all of the realtime EDL telemetry that Odyssey would have been relaying in realtime. If Odyssey is not there, we will still get everything MSL will transmit - simply delayed by a few hours as MRO downlinks and the ground team process and decode that recording.

Wouldn't some limited direct transmit get recorded from Earth?

As the press kit describes, there are direct to earth X-band tones, just like Pathfinder and MER. However - the Earth sets behind the vehicle somewhere between chute deployment and heatshield deployment, so they will be lost at that time.

[malgar]

As the press kit describes, there are direct to earth X-band tones.

How is the planned sequence of X-band tones?

The first one is after parachute deployment, and then? Is it a continuos stream of tones or just "bips" after every important step of the landing?
Btw, my personal Human-band tones would be the cheers from mission control room Which steps of the landing do you think will be celebrated?

[Astro0]

There are tones from Cruise stage sep all the way through each phase of EDL.

I certainly recommend that everyone take time to read back through this and all the other relevant MSL threads.
A lot of what is being asked is already answered there.

There's also answers to be found by Googling the question or checking the MSL EDL Press Kit.

[climber]

As I red somewhere, if ODY isn't in the right position, the "7 minutes or Terror" will last much longer

[MahFL]

There seems to be a glaring error in the press kit, it refers to a post launch briefing, after the landing.

[Explorer1]

Well, technically it is 'post-launch', right, so not really a typo?