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MSL Cruise Phase
nprev
post Nov 26 2011, 03:50 PM
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Okay, we're off and running! Please post all comments relating to MSL's transit to Mars here.


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Ron Hobbs
post Nov 30 2011, 08:17 PM
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From what I thought was a very informative article in the January 2011 issue of Aerospace America from the AIAA:

"Things begin to happen fast at backshell and parachute separation, but the first thing the sky crane and Curiosity do is nothing." ohmy.gif "The contraption is programmed to free-fall for 1 sec to be well clear of the ... parachute canopy, risers, and backshell."

"Next (after MLE ignition) the vehicle maneuvers laterally to prevent having the backshell and parachute collide in midair or land on top of each other - the worst of luck 150 million miles from Earth."

This may have changed, although some kind of collision avoidance must still be included.

Ron
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djellison
post Nov 30 2011, 10:33 PM
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Ron - as far as I know, that article has it about right. (Apart from semantics of MLE fire up.... they're just warming up at 1% before the drop)

http://trs-new.jpl.nasa.gov/dspace/handle/2014/41629 was our go-to document for EDL

QUOTE
At initiation of BSS, separation nuts are fired to release the PDV from the backshell. For one second, the PDV freefalls out of the backshell to provide sufficient separation to avoid inadvertent recontact when maneuvering begins. Once this one-second freefall is complete, the eight MLEs are throttled up from their 1% near-shutdown condition and the PDV begins a 2.2 second period during which any residual attitude rates from the BSS event are removed and the PDV assumes a pre-defined attitude for the beginning of powered descent...
...During Powered Approach, the PDV follows a 3-D polynomial trajectory which was computed at BSS. As the PDV follows the polynomial, horizontal velocity is smoothly brought to zero while vertical velocity is simultaneously brought to 20 m/s. The end point of the trajectory is about 100 m above the surface and 300 m perpendicular to the plane of the entry trajectory. Since the PDV is actively slowing, the parachute and backshell will actually travel past the PDV and reach the surface ahead of the PDV. The 300 m divert distance is adequate to ensure the PDV does not land on the parachute or backshell. Once the endpoint of the Powered Approach trajectory is reached, the Constant Velocity Accordion begins


So there isn't a discreet avoidance maneuver as there was with PHX ( although PHX didn't actually need it's after all ) - but avoidance is part of the mix of the trajectory design from BSS to the CVP

Enough TLA's smile.gif

Thanks John - the heavy lifting was Bohemian Grey - I just pointed them in the right direction. The BSS is the moment I'm most proud of...and showing it to the EDL team for the first time one the highlights of my short time at JPL so far. It involved a spontaneous high-five across a conference room table smile.gif
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Posts in this topic
- nprev   MSL Cruise Phase   Nov 26 2011, 03:50 PM
- - Oersted   The live footage of the first couple of kilomete...   Nov 26 2011, 03:52 PM
- - climber   Oppy, here I come ! Waiting for post launch co...   Nov 26 2011, 04:07 PM
|- - Oersted   QUOTE (climber @ Nov 26 2011, 05:07 PM) O...   Nov 26 2011, 04:34 PM
|- - climber   QUOTE (Oersted @ Nov 26 2011, 05:34 PM) W...   Nov 26 2011, 04:48 PM
- - nprev   Yeah, that was indeed a beautiful sight to behold,...   Nov 26 2011, 04:08 PM
- - vikingmars   ... and we just had champagne at home near Paris t...   Nov 26 2011, 04:14 PM
- - DEChengst   They just started showing the title card for the p...   Nov 26 2011, 05:34 PM
|- - sgendreau   EDIT2: Not much news. No news is good news for ...   Nov 26 2011, 06:01 PM
- - dmg   Anyone know why the telemetry pickup from the laun...   Nov 26 2011, 07:07 PM
- - MarsEngineer   No news is good news indeed! We are watching...   Nov 26 2011, 09:51 PM
|- - Pando   QUOTE (MarsEngineer @ Nov 26 2011, 02:51 ...   Nov 26 2011, 11:16 PM
|- - Oersted   QUOTE (MarsEngineer @ Nov 26 2011, 10:51 ...   Nov 27 2011, 12:20 AM
- - climber   Tanks Rob, I was browsing like mad to get any news...   Nov 26 2011, 10:11 PM
- - MERovingian   Bravo to all the teams involved, JPL, ULA, NASA, K...   Nov 26 2011, 10:52 PM
- - nprev   Rob, thanks very much for taking the trouble durin...   Nov 27 2011, 12:01 AM
- - Explorer1   Actually the last EDL was in 2008 with the Phoenix...   Nov 27 2011, 12:01 AM
- - Oersted   I uploaded footage of the launch and spacecraft se...   Nov 27 2011, 12:44 AM
|- - Syrinx   Thank you sir for the videos. I was unable to wat...   Nov 27 2011, 02:02 AM
- - tanjent   I'm having some trouble with "data dropou...   Nov 27 2011, 03:34 AM
|- - kwan3217   (Full inline quote removed- Mod) The apogee for a...   Nov 27 2011, 02:23 PM
|- - scalbers   QUOTE (kwan3217 @ Nov 27 2011, 03:23 PM) ...   Nov 27 2011, 04:08 PM
|- - kwan3217   (Full inline quote removed- Mod) The guys at JPL ...   Nov 28 2011, 08:58 PM
- - john_s   I was watching those numbers too. The apogee shou...   Nov 27 2011, 03:54 AM
- - tanjent   OK - I bet it actually finds the perigee by lookin...   Nov 27 2011, 04:04 AM
|- - MahFL   The separation video was just awesome, although I ...   Nov 27 2011, 04:49 AM
|- - OKB001   QUOTE (MahFL @ Nov 26 2011, 08:49 PM) The...   Nov 27 2011, 05:59 AM
- - tanjent   Well, the altitude should be directly observable b...   Nov 27 2011, 02:50 PM
- - Astro0   A little late to the party I guess. My weekend was...   Nov 27 2011, 10:05 PM
|- - MarsEngineer   QUOTE (Astro0 @ Nov 27 2011, 02:05 PM) A ...   Nov 28 2011, 12:36 AM
- - Oersted   Oh, a rainbow to boot! Lovely panorama and tha...   Nov 27 2011, 10:30 PM
- - MarsEngineer   Hi all, Please take a look at the observations ma...   Nov 28 2011, 12:54 AM
- - nprev   ...words utterly fail me. Just remarkable. Many t...   Nov 28 2011, 12:59 AM
- - eoincampbell   WOW! Thanks for sharing another "Heimdall...   Nov 28 2011, 03:05 AM
- - tanjent   Quote: http://www.facebook.com/BrisbanePlanetarium...   Nov 28 2011, 08:36 AM
- - Oersted   That is an amazing timelapse! http://www.yout...   Nov 28 2011, 01:12 PM
- - Oersted   On my youtube page of MSL launch movies I am getti...   Nov 28 2011, 03:10 PM
|- - Greg Hullender   QUOTE (Oersted @ Nov 28 2011, 07:10 AM) ...   Nov 28 2011, 03:57 PM
- - Roby72   Here you could see Curiosity 10 hours 30 minutes a...   Nov 28 2011, 09:51 PM
- - Bobby   Question? Is there a site either through JPL or a...   Nov 29 2011, 12:40 AM
- - punkboi   http://space.jpl.nasa.gov/ MSL's position sho...   Nov 29 2011, 12:49 AM
- - Astro0   As usual, Eyes on the Solar System can take us all...   Nov 30 2011, 04:12 AM
- - Explorer1   Is the cruise stage's spin in real-time? Great...   Nov 30 2011, 05:57 AM
|- - MahFL   Don't forget, the whole Rover is spinning....l...   Nov 30 2011, 12:08 PM
- - MahFL   I am not sure how accurate the model is but it loo...   Nov 30 2011, 12:13 PM
- - ilbasso   Should we bring her back for repairs?   Nov 30 2011, 12:18 PM
|- - MahFL   I just read that the hand lens imager can take pic...   Nov 30 2011, 01:52 PM
|- - eoincampbell   QUOTE (MahFL @ Nov 30 2011, 05:52 AM) ......   Nov 30 2011, 04:19 PM
|- - Deimos   http://msl-scicorner.jpl.nasa.gov/Instruments/MAHL...   Nov 30 2011, 04:50 PM
- - pospa   Also VERY cool would be any MAHLI picture from ins...   Nov 30 2011, 02:22 PM
- - climber   You can even dream of a shot of Spacecraft separat...   Nov 30 2011, 03:05 PM
- - ElkGroveDan   The next images we'll see from MSL will likely...   Nov 30 2011, 03:46 PM
- - djellison   QUOTE (pospa @ Nov 30 2011, 06:22 AM) Als...   Nov 30 2011, 04:40 PM
|- - MarsEngineer   QUOTE (djellison @ Nov 30 2011, 08:40 AM)...   Nov 30 2011, 04:57 PM
- - john_s   I love the idea of the rover doing an "arms-l...   Nov 30 2011, 05:21 PM
- - djellison   It took all the way until working on the MSL anima...   Nov 30 2011, 05:23 PM
- - climber   I noticed on a previous video that legs extended a...   Nov 30 2011, 06:18 PM
- - djellison   Actually - the descent stage thrusters do start be...   Nov 30 2011, 07:25 PM
- - john_s   That "hard drop", with the rover falling...   Nov 30 2011, 07:38 PM
|- - climber   I read, where?, that, as soon as released, Curiosi...   Nov 30 2011, 07:53 PM
- - Ron Hobbs   From what I thought was a very informative article...   Nov 30 2011, 08:17 PM
|- - djellison   Ron - as far as I know, that article has it about ...   Nov 30 2011, 10:33 PM
|- - MahFL   Well I should have known better the tragectory man...   Dec 1 2011, 12:23 AM
- - Syrinx   http://www.sciencedaily.com/releases/2011/...11201...   Dec 2 2011, 07:42 AM
- - stevesliva   Seems to be regurgitating the same source: http://...   Dec 2 2011, 07:56 AM
|- - MahFL   The Eyes on the Solar System make my IE 8 crash af...   Dec 2 2011, 03:10 PM
|- - djellison   QUOTE (MahFL @ Dec 2 2011, 07:10 AM) The ...   Dec 2 2011, 06:52 PM
- - B Bernatchez   No problems for me (that wouldn't be fixed by ...   Dec 2 2011, 05:42 PM
- - Mars Attack   I'm a bit concerned about the reported reset o...   Dec 4 2011, 02:57 PM
|- - stevesliva   QUOTE (Mars Attack @ Dec 4 2011, 10:57 AM...   Dec 4 2011, 04:55 PM
||- - Mars Attack   QUOTE (stevesliva @ Dec 4 2011, 04:55 PM)...   Dec 4 2011, 05:20 PM
|- - Paolo   QUOTE (Mars Attack @ Dec 4 2011, 03:57 PM...   Dec 4 2011, 07:04 PM
- - ElkGroveDan   There is extra fuel aboard and my understanding is...   Dec 4 2011, 03:42 PM
|- - centsworth_II   QUOTE (ElkGroveDan @ Dec 4 2011, 10:42 AM...   Dec 4 2011, 07:18 PM
- - Hiwayman   Sorry for this being posted in the wrong forum, bu...   Dec 4 2011, 03:56 PM
|- - Oersted   QUOTE (Hiwayman @ Dec 4 2011, 04:56 PM) S...   Dec 4 2011, 08:43 PM
- - elakdawalla   Someone else pointed this out to me on the Atlas f...   Dec 4 2011, 04:19 PM
|- - Hiwayman   QUOTE (elakdawalla @ Dec 4 2011, 09:19 AM...   Dec 4 2011, 04:28 PM
|- - climber   QUOTE (elakdawalla @ Dec 4 2011, 05:19 PM...   Dec 4 2011, 06:52 PM
- - djellison   From http://trs-new.jpl.nasa.gov/dspace/handle/201...   Dec 4 2011, 08:23 PM
- - nprev   Yeah, it really was a sweet launch...and major kud...   Dec 4 2011, 08:49 PM
- - Mars Attack   Mr. Doug Djellison, any chance that you could expa...   Dec 4 2011, 11:00 PM
- - djellison   We hope to - but it's entirely a matter of bud...   Dec 4 2011, 11:12 PM
|- - climber   QUOTE (djellison @ Dec 5 2011, 12:12 AM) ...   Dec 5 2011, 11:38 AM
- - punkboi   You can now view MSL's current position in spa...   Dec 7 2011, 05:57 AM
- - Syrinx   http://space.jpl.nasa.gov/cgi-bin/wspace?t...=1...   Dec 7 2011, 07:56 AM
- - Lucas   For the impatient among us... http://space.jpl...   Dec 7 2011, 02:56 PM
- - pospa   T +18 days - MSL has about 9% of its cruise done a...   Dec 14 2011, 02:32 PM
- - punkboi   Where is Curiosity now? There's now a dedicate...   Dec 14 2011, 10:27 PM
- - Lunik9   New sunspot 1387 erupted during the late hours of ...   Dec 26 2011, 09:28 AM
- - Explorer1   How large would an event have to be to seriously i...   Dec 26 2011, 11:40 PM
|- - centsworth_II   According to Curiosity and the Solar Storm, CMEs p...   Dec 27 2011, 08:05 AM
- - pospa   TCM-1 scheduled for Jan 11th, dv 5,5 m/s. Then eq...   Jan 6 2012, 11:03 PM
- - pospa   TCM-1 completed successfully. Rob Manning describ...   Jan 13 2012, 10:01 AM
- - Phil Stooke   "By the time a CME reaches the Earth-Mars exp...   Jan 13 2012, 12:12 PM
- - climber   According to AW&ST next trajectory correction ...   Jan 31 2012, 06:53 PM
- - pospa   Not sure if mentioned here before, but radio amate...   Feb 6 2012, 09:53 AM
- - MahFL   Software fix for Star Tracker problem. Tracker   Feb 10 2012, 01:37 PM
- - Mars Attack   The computer that received the software fix, is i...   Mar 1 2012, 03:36 PM
- - MahFL   QUOTE (Mars Attack @ Mar 1 2012, 03:36 PM...   Mar 2 2012, 12:20 AM
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