IPB

Welcome Guest ( Log In | Register )

MSL reasons for delay
mcaplinger
post Mar 4 2009, 03:33 PM
Post #1


Senior Member
****

Group: Members
Posts: 2547
Joined: 13-September 05
Member No.: 497



I wanted to make sure that everyone interested sees Adrian Brown's articles at http://www.thespacereview.com/article/1319/1 and http://www.thespacereview.com/article/1318/1 about the technical and budgetary problems with MSL that led to the launch slip. While I can't claim to be privy to the budgetary and political issues at the mission level, the technical discussion seems like a fair summary of the situation as I understand it, at least as good a one as can be gathered from public sources.

People in other forums have complained about errors in these articles, but without giving specific examples or providing any factual basis for their objections. I don't find that very useful. If there are real flaws in this account, I'd be quite interested to know what they are.

p.s. I guess we need to change the name of this subforum. sad.gif


--------------------
Disclaimer: This post is based on public information only. Any opinions are my own.
Go to the top of the page
 
+Quote Post
 
Start new topic
Replies
SpaceListener
post Jul 13 2009, 08:22 PM
Post #2


Member
***

Group: Members
Posts: 279
Joined: 19-August 07
Member No.: 3299



dtolman,

I think that this might be a leak news from news media since it has no further detail information about the reason. If NASA informs this, I hope it would be well covered and explained.

About this I have many questions and I am not able to know what is the real reason. It would be to too early to get well acquainted.

I think that NASA must know it perfectly whether if it is or not necessary after studying their cons and pros. The main electrical energy would be based of nuclear and the solar ones would be interpreted as an supplemental and not as critical energy. On the other hand, it would to be insufficient to supply an extra needed energy due to a new requirements, or present instruments that might need an additional not planned electrical energy needs.

An additional battery capacity would be the most sounding acceptable but up to here, it is not worth to further discuss without knowing their cons/pros.
Go to the top of the page
 
+Quote Post
dtolman
post Jul 14 2009, 01:25 PM
Post #3


Member
***

Group: Members
Posts: 129
Joined: 20-April 05
Member No.: 291



SpaceListener,
The main source of this seems to be an article in Nature - http://www.nature.com/news/2009/090710/ful...s.2009.664.html.

I didn't see this in the summary, so it probably bears repeating. From the article (concerning cost and power overruns respectively):
QUOTE
The cause of the latest overrun is problems with motors, gearboxes and avionics controls. After switching from a dry to a wet lubricant, engineers have had trouble verifying the reliability of motors for the rover's robotic arm. Moreover, McCuistion says, a new snag was recently discovered: some of the premier instruments — the Sample Analysis at Mars or SAM instrument set — will suck twice as much power as was expected, and that means the rover needs to carry bigger batteries.


I'm assuming here that the "batteries" are the RTGs. not the L-I kind...is there sufficient P-238 unclaimed to supply larger batteries? as of early 2008, I read reports in the media that the unclaimed supply in the system was measurable counting on one hand (in kilograms). Or maybe they can find a clever way to shutdown systems to allow the SAM to run on the existing power supply.

Hopefully the latter is a viable solution. I doubt they can add kilograms of battery, without cutting weight from somewhere else...
Go to the top of the page
 
+Quote Post
mcaplinger
post Jul 14 2009, 01:53 PM
Post #4


Senior Member
****

Group: Members
Posts: 2547
Joined: 13-September 05
Member No.: 497



QUOTE (dtolman @ Jul 14 2009, 06:25 AM) *
I'm assuming here that the "batteries" are the RTGs. not the L-I kind...I doubt they can add kilograms of battery, without cutting weight from somewhere else...

No, they are talking about the secondary batteries (I forget if they are using Li-ion or something else.) The RTG doesn't provide enough peak power to run the systems directly, so it has to be used to trickle-charge the batteries.

As for mass, I expect that they have enough mass margin to add batteries if there is no operational workaround. At least our cameras are coming in well under on both mass and power relative to predictions (not that we were very big either way.)

And for JPL bashers, note that SAM is provided by GSFC, not JPL.


--------------------
Disclaimer: This post is based on public information only. Any opinions are my own.
Go to the top of the page
 
+Quote Post
dtolman
post Jul 14 2009, 02:17 PM
Post #5


Member
***

Group: Members
Posts: 129
Joined: 20-April 05
Member No.: 291



mcaplinger - thanks for the clarification. It can get confusing trying to parse power supply issues when everything ends up getting called "a battery" in the media.

Also - if anyone is interested - there is related information in this presentation to the NASA Advisory Committee (courtesy naswatch/spaceref):
http://images.spaceref.com/news/2009/PSS.Jun.09.Mars.pdf

The slide of interest from the presentation:
QUOTE
• Rover power system design does not meet present mission requirements, requiring additional battery capacity, and possibly solar array
– Increased energy requirements to keep actuators above safe operating temperature
– Almost double energy requirement to operate/conduct SAM instrument science/sample analysis scenarios
• The SAM instrument has not completed its environmental qualification program, and the wide range
pump has not demonstrated life qualification (hours of operation and start/stop) requirements.


The bullets above make it sound more serious (at least to me), than the Nature summary. Does anyone have any idea if the problem is that they can't run the SAM with other operations running, or if they can't even draw enough power to run the SAM even by itself?
Go to the top of the page
 
+Quote Post
mcaplinger
post Jul 14 2009, 02:26 PM
Post #6


Senior Member
****

Group: Members
Posts: 2547
Joined: 13-September 05
Member No.: 497



QUOTE (dtolman @ Jul 14 2009, 06:17 AM) *
Does anyone have any idea if the problem is that they can't run the SAM with other operations running, or if they can't even draw enough power to run the SAM even by itself?

Almost certainly the first one. These are total energy problems, not instantaneous power problems. As such there are most likely operational workarounds, though they may not be very attractive.


--------------------
Disclaimer: This post is based on public information only. Any opinions are my own.
Go to the top of the page
 
+Quote Post

Posts in this topic
- mcaplinger   MSL reasons for delay   Mar 4 2009, 03:33 PM
- - djellison   Thanks for linking to these Mike - they're ver...   Mar 4 2009, 03:41 PM
|- - ElkGroveDan   QUOTE (djellison @ Mar 4 2009, 07:41 AM) ...   Mar 4 2009, 04:49 PM
|- - algorimancer   QUOTE (djellison @ Mar 4 2009, 09:41 AM) ...   Mar 5 2009, 08:16 PM
|- - mcaplinger   QUOTE (algorimancer @ Mar 5 2009, 12:16 P...   Mar 5 2009, 09:34 PM
||- - ElkGroveDan   QUOTE (mcaplinger @ Mar 5 2009, 01:34 PM)...   Mar 5 2009, 10:36 PM
|||- - mcaplinger   Forgive me if I lose patience with armchair engine...   Mar 5 2009, 11:20 PM
||- - algorimancer   QUOTE (mcaplinger @ Mar 5 2009, 03:34 PM)...   Mar 6 2009, 01:41 PM
|- - jmcdesign   "In retrospect they might simply have placed ...   Mar 6 2009, 04:23 PM
- - dvandorn   Yeah -- I've been meaning to ask when Phoenix ...   Mar 4 2009, 06:24 PM
|- - tedstryk   I was thinking (and still think) that it would be ...   Mar 4 2009, 08:58 PM
|- - ugordan   QUOTE (dvandorn @ Mar 4 2009, 07:24 PM) I...   Mar 4 2009, 09:04 PM
- - monitorlizard   I had also seen the Adrian Brown essays. In his r...   Mar 5 2009, 03:58 PM
- - stevesliva   You're forgiven. It is armchair-knee-jerk refl...   Mar 6 2009, 12:06 AM
|- - centsworth_II   QUOTE (stevesliva @ Mar 5 2009, 07:06 PM)...   Mar 6 2009, 02:14 AM
|- - mcaplinger   QUOTE (centsworth_II @ Mar 5 2009, 06:14 ...   Mar 6 2009, 03:43 AM
- - djellison   You're thinking of the Stardust Navcam. That...   Mar 6 2009, 12:18 AM
- - stevesliva   To be clear, I did not mean to imply MSSS had some...   Mar 6 2009, 12:35 AM
- - lyford   "Less moving parts!?!?!" Th...   Mar 6 2009, 01:53 AM
- - dvandorn   Let's face it, guys -- anything that has movin...   Mar 6 2009, 03:27 AM
- - djellison   Of course, we have ChemCam as an ultra high res im...   Mar 6 2009, 04:41 PM
- - Cruzeiro do Sul   One question about the RTG in MSL: in front of the...   May 6 2009, 12:45 PM
|- - SpaceListener   QUOTE (Cruzeiro do Sul @ May 6 2009, 06:4...   May 8 2009, 12:42 AM
- - monitorlizard   http://mars.jpl.nasa.gov/msl/mission/technology/po...   May 8 2009, 09:56 AM
|- - Cruzeiro do Sul   5% is a small amount of lost, so we can hope that ...   May 11 2009, 02:34 PM
- - climber   You'll be interested in this .pdf presentation...   Jul 11 2009, 10:38 AM
- - SpaceListener   And hope that these probably existence of solar pa...   Jul 11 2009, 03:06 PM
|- - centsworth_II   QUOTE (SpaceListener @ Jul 11 2009, 10:06...   Jul 11 2009, 03:48 PM
||- - mcaplinger   QUOTE (centsworth_II @ Jul 11 2009, 07:48...   Jul 13 2009, 08:24 PM
||- - helvick   This isn't completely true - vertically placed...   Jul 13 2009, 09:51 PM
|- - djellison   QUOTE (SpaceListener @ Jul 11 2009, 04:06...   Jul 11 2009, 04:45 PM
||- - centsworth_II   QUOTE (djellison @ Jul 11 2009, 11:45 AM)...   Jul 11 2009, 06:44 PM
|- - dtolman   QUOTE (SpaceListener @ Jul 11 2009, 10:06...   Jul 13 2009, 07:48 PM
- - dtolman   Isn't it a little late in the game to figure o...   Jul 13 2009, 07:55 PM
|- - SFJCody   I hope there's a TV documentary crew following...   Jul 13 2009, 08:06 PM
- - SpaceListener   dtolman, I think that this might be a leak news f...   Jul 13 2009, 08:22 PM
|- - dtolman   SpaceListener, The main source of this seems to be...   Jul 14 2009, 01:25 PM
|- - mcaplinger   QUOTE (dtolman @ Jul 14 2009, 06:25 AM) I...   Jul 14 2009, 01:53 PM
|- - dtolman   mcaplinger - thanks for the clarification. It can ...   Jul 14 2009, 02:17 PM
|- - mcaplinger   QUOTE (dtolman @ Jul 14 2009, 06:17 AM) D...   Jul 14 2009, 02:26 PM
- - Enceladus75   I think MSL was just too big a leap, technology wi...   Jul 16 2009, 01:52 AM
- - BrianL   I would say that Spirit and Oppy were a much bigge...   Jul 16 2009, 02:37 AM
- - dvandorn   Brian? Read "Roving Mars" by Steve Squy...   Jul 16 2009, 02:55 AM
|- - mcaplinger   QUOTE (dvandorn @ Jul 15 2009, 07:55 PM) ...   Jul 16 2009, 03:42 AM
- - nprev   To be fair (and not to stray OT), major projects o...   Jul 16 2009, 04:19 AM
- - dvandorn   Very true, Nick. Especially for revolutionary pro...   Jul 16 2009, 04:40 AM
|- - MahFL   Often a low estimate is the only way to get a proj...   Jul 16 2009, 12:45 PM
|- - stevesliva   QUOTE (MahFL @ Jul 16 2009, 08:45 AM) Loo...   Jul 16 2009, 03:29 PM
|- - tedstryk   The problem is that MSL is so much larger in terms...   Jul 16 2009, 06:50 PM
|- - mcaplinger   QUOTE (tedstryk @ Jul 16 2009, 10:50 AM) ...   Jul 17 2009, 01:59 AM
|- - tedstryk   Right, but that means that x percent overrun is tw...   Jul 17 2009, 03:28 AM
- - BrianL   I wasn't suggesting the MERs had an easy road....   Jul 16 2009, 12:50 PM
- - climber   I agree Ted, but if the beast works, who knows wha...   Jul 16 2009, 07:10 PM
|- - SFJCody   I guess another reason MSL has to be such a big ve...   Jul 16 2009, 07:26 PM
- - imipak   QUOTE (Kierkegaard @ 19th century)"Life ...   Jul 16 2009, 08:49 PM
- - centsworth_II   This is the kind of torturous process that leads t...   Jul 16 2009, 08:55 PM
- - peter59   http://news.bbc.co.uk/2/hi/science/nature/8168954....   Jul 27 2009, 08:17 AM
|- - tedstryk   QUOTE (peter59 @ Jul 27 2009, 09:17 AM) h...   Aug 20 2009, 05:45 PM
- - mcaplinger   Hadn't seen anyone discussing the MSL status r...   Oct 16 2009, 11:02 PM
|- - Oersted   Yes, thx so much for digging up this info, I avidl...   Oct 18 2009, 10:13 PM
- - James Sorenson   Ohhh Thanks for pointing that out!, I had not ...   Oct 17 2009, 01:34 AM
- - peter59   More problems, greater costs. This is starting to ...   Oct 21 2009, 01:39 PM
|- - MahFL   Ahh crap, how unlucky, lets hope things turn out o...   Oct 21 2009, 08:20 PM
- - djellison   Given the litigious nature of US law and pending c...   Oct 22 2009, 07:15 AM
- - nprev   (sorry...we need a "deeply-embarrassed-'c...   Oct 22 2009, 07:25 AM
- - Holder of the Two Leashes   Guess I should've added a few "if"s ...   Oct 22 2009, 02:11 PM
- - djellison   As a guidance - if you have to prefix your post wi...   Oct 23 2009, 06:23 PM
- - climber   MSL Readiness to proceed review: http://nasawatch....   Nov 18 2009, 11:06 PM
|- - Greg Hullender   QUOTE (climber @ Nov 18 2009, 03:06 PM) M...   Nov 18 2009, 11:16 PM
- - elakdawalla   I split out some posts about delivery of component...   Jun 12 2010, 02:00 AM


Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 31st October 2024 - 11:25 PM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member.