IPB

Welcome Guest ( Log In | Register )

Dust Storm- Opportunity EOM, the end of the beginning of a new era in robotic spaceflight
djellison
post Jun 5 2018, 03:05 PM
Post #1


Founder
****

Group: Chairman
Posts: 14431
Joined: 8-February 04
Member No.: 1



Expect a quiet few sols - http://www.lpl.arizona.edu/~lemmon/mars-tau-b.html
SOL TAU
5097 0.65
5098 0.64
5099 0.67
5100 0.64
5101 0.60
5102 0.60
5103 0.61
5104 1.55
5105 ****
5106 2.12

Go to the top of the page
 
+Quote Post
 
Start new topic
Replies
Don1
post Jun 16 2018, 09:20 PM
Post #2


Junior Member
**

Group: Members
Posts: 94
Joined: 11-August 12
Member No.: 6536



I did try to estimate the illumination based on the solar panel output, and I was puzzled by why that was coming out so differently from the estimate based on tau. What bothers me about the 22 Watt-hr quoted for the solar panel production is that seems way too much to just run a clock. Are we certain that number is accurate?

Also, if there was a break in the storm the rover might have gotten half an hour of sun which would charge the battery a little. We don't know how much the panels were producing at the time the tau was measured.

On a different topic, the 8 RHUs are providing 192 Watt-hours of energy in the form of heat. If I remember correctly, sunny day production from the panels is about 600 Watt-hours of electricity. So a big chunk of the energy budget of this "solar" powered rover is actually from nuclear sources, even when it is sunny. That surprised me when I worked out the numbers.
Go to the top of the page
 
+Quote Post
mcaplinger
post Jun 16 2018, 11:38 PM
Post #3


Senior Member
****

Group: Members
Posts: 2502
Joined: 13-September 05
Member No.: 497



QUOTE (Don1 @ Jun 16 2018, 01:20 PM) *
What bothers me about the 22 Watt-hr quoted for the solar panel production is that seems way too much to just run a clock. Are we certain that number is accurate?

No, and it was a bit of an off-the-cuff answer, but barring some additional information from the project it's all we have to go on, and it's not implausible given what details of the design we do know. For example, some types of Q-Tech oscillators really do draw 40 mA just for the oscillator, and then for a complete clock there has to be a counter and maybe some other stuff -- the fault protection paper references a "mission clock FPGA".

I also don't fully understand how the scheduling of transmission and reception periods happens if the mission clock is lost. This seemed to introduce a lot of complexity into the attempted recovery process for Spirit. Presumably without the mission clock there's no way for the rover to figure when 11 LST is (in theory it could do with from solar power production but that would vary a lot based on tau, tilt, dust on the panels, etc.); AFAIK this scenario isn't described in the fault protection paper.


--------------------
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
- djellison   Dust Storm- Opportunity EOM   Jun 5 2018, 03:05 PM
- - nprev   Breaking news: As Mars nears one of its closest pe...   Jun 9 2018, 06:38 AM
- - Sean   Oh god.   Jun 9 2018, 11:17 AM
- - fredk   Some details of the storm activity at the MRO MARC...   Jun 9 2018, 02:17 PM
- - James Sorenson   Good luck to Opportunity and to the very talented ...   Jun 9 2018, 06:44 PM
- - Explorer1   Given the length of the mission, it was only a mat...   Jun 9 2018, 07:18 PM
- - marsophile   Once the dust storm per se abates, there may be a ...   Jun 10 2018, 12:46 AM
- - Phil Stooke   "I wonder if there might be some advantage at...   Jun 10 2018, 08:21 PM
- - djellison   When you have skies this dusty - the single best s...   Jun 10 2018, 09:03 PM
- - centsworth_II   Also, with panels flat, a gust of wind from any d...   Jun 10 2018, 09:21 PM
- - djellison   Moreover - it's not dust 'fall' that h...   Jun 10 2018, 09:34 PM
|- - Dalhousie   QUOTE (djellison @ Jun 10 2018, 09:34 PM)...   Jun 10 2018, 11:01 PM
|- - djellison   QUOTE (Dalhousie @ Jun 10 2018, 04:01 PM)...   Jun 11 2018, 12:43 AM
- - pioneer   Will Opportunity get a chance to send back images ...   Jun 10 2018, 10:07 PM
- - djellison   Other than taking occasional tau measurements of t...   Jun 10 2018, 10:13 PM
- - ngunn   I wonder how much tilt you need to shake some dust...   Jun 10 2018, 10:29 PM
- - djellison   The sort of slope that represents a threat to vehi...   Jun 10 2018, 10:38 PM
- - ngunn   Sure, my question was not about managing the situa...   Jun 10 2018, 11:11 PM
|- - djellison   QUOTE (ngunn @ Jun 10 2018, 03:11 PM) If ...   Jun 11 2018, 12:30 AM
|- - RoverDriver   QUOTE (ngunn @ Jun 10 2018, 04:11 PM) ......   Jun 13 2018, 04:21 PM
- - marsophile   Is it still true that the prevailing wind is upslo...   Jun 10 2018, 11:38 PM
- - pioneer   Thanks. I thought I saw an image taken by one of ...   Jun 11 2018, 12:55 AM
- - James Sorenson   Oppy as well as Spirit did take some images of the...   Jun 11 2018, 01:15 AM
- - serpens   Yep. Spirit provided a sequence of images that p...   Jun 11 2018, 03:49 AM
- - djellison   This mosaic is from Opportunity https://www.nasa.g...   Jun 11 2018, 04:23 AM
|- - serpens   QUOTE (djellison @ Jun 11 2018, 04:23 AM)...   Jun 11 2018, 12:15 PM
- - James Sorenson   I am curious if the full frame wide range tau imag...   Jun 11 2018, 04:36 AM
- - Deimos   Hoping to see some new values added to that site s...   Jun 11 2018, 11:49 AM
- - Deimos   I suppose since the news is here, it is on the plo...   Jun 11 2018, 07:32 PM
|- - fredk   QUOTE (Deimos @ Jun 11 2018, 08:32 PM) A ...   Jun 11 2018, 07:47 PM
|- - MoreInput   I just can't believe how fast the tau increase...   Jun 11 2018, 07:49 PM
- - mcaplinger   Has Opportunity ever been in a low-power fault sta...   Jun 11 2018, 09:52 PM
- - serpens   I guess Opportunity would be better placed to come...   Jun 11 2018, 11:28 PM
|- - mcaplinger   QUOTE (serpens @ Jun 11 2018, 03:28 PM) I...   Jun 12 2018, 05:47 AM
- - marsophile   https://mars.nasa.gov/mer/newsroom/pressrel.../200...   Jun 12 2018, 12:33 AM
- - Hungry4info   It's apparently not as bad over Curiosity...   Jun 12 2018, 04:11 AM
|- - MahFL   QUOTE (Hungry4info @ Jun 12 2018, 04:11 A...   Jun 12 2018, 10:39 PM
- - PaulH51   NASA will host a media teleconference at 10:30 a.m...   Jun 12 2018, 09:36 PM
|- - HSchirmer   QUOTE (PaulH51 @ Jun 12 2018, 10:36 PM) N...   Jun 12 2018, 10:09 PM
- - xflare   Has there been any further communication from Oppo...   Jun 12 2018, 11:32 PM
|- - mcaplinger   QUOTE (xflare @ Jun 12 2018, 03:32 PM) Ha...   Jun 13 2018, 12:50 AM
- - RoverDriver   There will be a telecon tomorrow (Wednesday June 1...   Jun 13 2018, 12:46 AM
- - jccwrt   The JPL news story on the dust storm was updated t...   Jun 13 2018, 03:05 AM
|- - mcaplinger   QUOTE (jccwrt @ Jun 12 2018, 07:05 PM) th...   Jun 13 2018, 03:45 AM
- - serpens   Thanks for that link. I guess all that can be don...   Jun 13 2018, 04:15 AM
- - SpaceListener   Are the solar panels able to raise up? I say this ...   Jun 13 2018, 04:31 PM
|- - MahFL   QUOTE (SpaceListener @ Jun 13 2018, 05:31...   Jun 13 2018, 10:48 PM
- - Explorer1   No, those were a one-time use, though good thinki...   Jun 13 2018, 04:35 PM
- - djellison   People should think of their TV screen. It has d...   Jun 13 2018, 05:52 PM
- - Art Martin   The news conference was upbeat. They expect the r...   Jun 13 2018, 06:22 PM
- - mcaplinger   The good news from the press conference is that th...   Jun 13 2018, 11:24 PM
|- - marsophile   QUOTE (mcaplinger @ Jun 13 2018, 03:24 PM...   Jun 14 2018, 03:17 AM
- - PaulH51   ICYMI : Here is a link to the YouTube recording of...   Jun 14 2018, 12:35 AM
- - serpens   The extent of this dust storm seems to be emulatin...   Jun 14 2018, 02:13 AM
- - jccwrt   Another potential alternative is the 1977 dust sto...   Jun 14 2018, 02:55 AM
- - elakdawalla   Because a lot of questions being asked here were a...   Jun 14 2018, 03:27 AM
|- - mcaplinger   QUOTE (elakdawalla @ Jun 13 2018, 07:27 P...   Jun 14 2018, 04:09 AM
|- - elakdawalla   QUOTE (mcaplinger @ Jun 13 2018, 09:09 PM...   Jun 14 2018, 04:36 PM
- - Explorer1   The main thought I keeping coming back to is that ...   Jun 14 2018, 04:33 AM
|- - mcaplinger   QUOTE (Explorer1 @ Jun 13 2018, 08:33 PM)...   Jun 14 2018, 03:11 PM
|- - Gerald   QUOTE (mcaplinger @ Jun 14 2018, 05:11 PM...   Jun 14 2018, 05:30 PM
- - mcaplinger   https://trs.jpl.nasa.gov/handle/2014/43244 "T...   Jun 14 2018, 03:05 PM
- - Deimos   Not strictly true, at least if you're referrin...   Jun 14 2018, 05:59 PM
- - marsophile   New MARCI weather report: http://www.msss.com/mss...   Jun 14 2018, 08:02 PM
- - Steve G   To add a layman's context to the amount of sun...   Jun 15 2018, 03:19 AM
- - serpens   There are a lot of variables to consider there Ste...   Jun 15 2018, 06:38 AM
- - Don1   OK, so according to the source linked below, a sun...   Jun 15 2018, 09:02 AM
- - Gerald   If I understand it correctly, tau measurements are...   Jun 15 2018, 12:03 PM
- - Deimos   Exactly! The Sun itself was fainter than a ful...   Jun 15 2018, 01:46 PM
|- - mcaplinger   QUOTE (Deimos @ Jun 15 2018, 05:46 AM) So...   Jun 15 2018, 02:26 PM
|- - fredk   QUOTE (Deimos @ Jun 15 2018, 02:46 PM) Th...   Jun 15 2018, 04:37 PM
- - hendric   On the 22 WH just to keep the clock alive, maybe t...   Jun 15 2018, 07:19 PM
|- - mcaplinger   QUOTE (hendric @ Jun 15 2018, 11:19 AM) O...   Jun 15 2018, 10:26 PM
||- - hendric   QUOTE (mcaplinger @ Jun 15 2018, 05:26 PM...   Jun 17 2018, 02:31 PM
||- - mcaplinger   QUOTE (hendric @ Jun 17 2018, 06:31 AM) w...   Jun 17 2018, 03:36 PM
|- - marsophile   QUOTE (hendric @ Jun 15 2018, 11:19 AM) O...   Jun 16 2018, 02:58 AM
|- - mcaplinger   QUOTE (marsophile @ Jun 15 2018, 06:58 PM...   Jun 16 2018, 04:01 PM
- - Roby72   just as a reminder how Mars looked in 2001 fully i...   Jun 15 2018, 09:56 PM
- - siravan   Regarding tau and the efficiency of solar panels, ...   Jun 15 2018, 10:10 PM
- - serpens   As siravan noted the spectrum at the surface would...   Jun 16 2018, 01:13 AM
|- - Deimos   QUOTE (serpens @ Jun 16 2018, 01:13 AM) T...   Jun 16 2018, 01:30 PM
|- - fredk   QUOTE (Deimos @ Jun 16 2018, 02:30 PM) If...   Jun 16 2018, 11:30 PM
- - Don1   I did try to estimate the illumination based on th...   Jun 16 2018, 09:20 PM
|- - mcaplinger   QUOTE (Don1 @ Jun 16 2018, 01:20 PM) What...   Jun 16 2018, 11:38 PM
|- - MahFL   QUOTE (mcaplinger @ Jun 16 2018, 11:38 PM...   Jun 17 2018, 08:44 AM
|- - mcaplinger   QUOTE (MahFL @ Jun 17 2018, 12:44 AM) The...   Jun 17 2018, 02:21 PM
- - Don1   QUOTE (mcaplinger @ Jun 16 2018, 04:38 PM...   Jun 17 2018, 09:05 AM
- - serpens   While the GaInP top cell is the limiting (short ci...   Jun 17 2018, 12:48 PM
- - fredk   I guess the question is: how does the rover decide...   Jun 17 2018, 02:34 PM
|- - mcaplinger   QUOTE (fredk @ Jun 17 2018, 06:34 AM) Mor...   Jun 17 2018, 03:41 PM
||- - marsophile   QUOTE (mcaplinger @ Jun 17 2018, 07:41 AM...   Jun 17 2018, 06:57 PM
||- - mcaplinger   QUOTE (marsophile @ Jun 17 2018, 10:57 AM...   Jun 18 2018, 12:11 AM
|- - djellison   QUOTE (fredk @ Jun 17 2018, 06:34 AM) I g...   Jun 17 2018, 11:42 PM
- - scalbers   How severe is this dust storm compared with others...   Jun 17 2018, 07:55 PM
|- - mcaplinger   QUOTE (scalbers @ Jun 17 2018, 11:55 AM) ...   Jun 17 2018, 08:11 PM
|- - serpens   QUOTE (scalbers @ Jun 17 2018, 08:55 PM) ...   Jun 18 2018, 12:19 AM
- - fredk   From the latest MRO weather report: QUOTE By the e...   Jun 20 2018, 05:35 PM
- - mcaplinger   http://www.planetary.org/explore/space-top...mer-u...   Jun 20 2018, 09:57 PM
- - djellison   "The Martian dust storm has grown in size and...   Jun 20 2018, 10:31 PM
- - JRehling   Christopher Go is the ace of [superior planet] ast...   Jun 21 2018, 03:29 AM
5 Pages V   1 2 3 > » 


Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 19th March 2024 - 03:13 AM
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.