Instrument and Mechanical Status Approaching Sol 2000 |
Instrument and Mechanical Status Approaching Sol 2000 |
Jul 1 2009, 07:11 PM
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#1
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Junior Member Group: Members Posts: 90 Joined: 23-February 09 From: Edmonton, Alberta Member No.: 4611 |
I've just finished re-reading Roving Mars for the 3rd or 4th time and it's still a brilliant insight on to all the hard work and crazy things that went wrong and right to get the girls to Mars and then their story for the first sols on Mars. It's fun to read about the debate on how long to keep Oppy in Eagle (6 or 10 days... they chose 6 since 10 was 1/4 of the science mission available after standup and the worries about cracking the beam splitter on miniTES with deep sleep. How dust would kill them both by sol 200...
I thought is might be a good idea to take an inventory of the girls as Spirit approaches 2000 sols (1953 at time of post) To take a quote from one of my favorite movies "Let's look at this thing from a... um, from a standpoint of status. What do we got on the spacecraft that's good?" (Gene Kranz/Ed Harris Apollo 13) (we have an amazing amount that IS) MI - seems pretty good on both rovers. Little or no dust contamination RAT - Main grinding tool unusable on both. Brushes? APXS - ??? miniTES - OK on Spirit, unusable on Oppy due to dust contamination of mirror in periscope (currently trying to clear by leaving open to elements) Mossbauer - Approaching half life of radiation source so sensing takes twice as long (?) IDD - Spirit OK, Oppy has shoulder seizure, stuck heater switch Pancam - Both OK Navcam - Spirit OK, Oppy seems to have some dust FHaz Cam - Both a bit dusty (?) Rhaz Cam - Both a bit dusty (?) Wheels - Spirit RF seized, Oppy RF elevated currents moderated by rest and backward driving. Power- Spirit ~900whr Oppy ~450whr Please correct mistakes and update as you can... oh..btw as of this post Spirit is stuck at Troy. I'm betting we'll be roving again by 2000 |
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Jul 1 2009, 07:36 PM
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#2
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Senior Member Group: Members Posts: 2920 Joined: 14-February 06 From: Very close to the Pyrénées Mountains (France) Member No.: 682 |
Good idea JayB.
Sundial - Still OK on both -------------------- |
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Jul 1 2009, 07:57 PM
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#3
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Senior Member Group: Members Posts: 1887 Joined: 20-November 04 From: Iowa Member No.: 110 |
QUOTE Mossbauer - Approaching half life of radiation source so sensing takes twice as long (?) The half life is 271 days, it now takes a couple of weeks to do what initially took part of a sol. |
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Jul 1 2009, 08:32 PM
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#4
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Founder Group: Chairman Posts: 14432 Joined: 8-February 04 Member No.: 1 |
Spirit RAT is just brushing. Oppy RAT as far as I know, can still drill (given that it's spent it's life drilling into cottage cheese rather than basalt)
All Haz, Nav and Pan have dust - Oppy Pancam is probably the worst. And, one issue we don't often mention. Spirit X-Band channel clashes with MRO. |
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Jul 1 2009, 09:13 PM
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#5
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Member Group: Members Posts: 813 Joined: 8-February 04 From: Arabia Terra Member No.: 12 |
The half life is 271 days, it now takes a couple of weeks to do what initially took part of a sol. Imagine the status updates in a couple of years! August 2011: Continued mossbauer integration. September 2011: Continued mossbauer integration. October 2011: Continued mossbauer integration... |
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Jul 1 2009, 10:44 PM
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#6
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Junior Member Group: Members Posts: 90 Joined: 23-February 09 From: Edmonton, Alberta Member No.: 4611 |
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Jul 2 2009, 06:01 AM
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#7
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Senior Member Group: Moderator Posts: 4279 Joined: 19-April 05 From: .br at .es Member No.: 253 |
Both Spirit and MRO X-band links with the DSN are at the same frequency. The reason was that it was never thought to have both machines alive at the same time.
Another issue with Opportunity is the RF wheel steering actuator which is stuck. |
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Jul 2 2009, 06:13 AM
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#8
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Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
One articulating component we don't hear much about is the HGA; I assume that no news is good news for both MERs!
-------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Jul 2 2009, 11:21 AM
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#9
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Member Group: Admin Posts: 976 Joined: 29-September 06 From: Pasadena, CA - USA Member No.: 1200 |
One articulating component we don't hear much about is the HGA; I assume that no news is good news for both MERs! That is correct. I never heard of any issues with that. One problem we have on Spirit, is the IMU (Inertial Measurement Unit). The IMU has gyros and accelerometers. There seems to be about 4 degrees difference between the gyros and the accelerometer data. It seems that the accelerometers are OK ut gyros are off. Also, amazingly enough in spite of the loss of azimuth actuator on Opportunity we can still use all the instruments and do all the observations, including MI mosaics. The IDD can reach only a narrow strip in front of the rovers but we are getting good at positioning the rover accurately enough to get to the science targets. Regarding the RAT: Spirit: grinding bit are worn out, we can only do brushing Opportunity: grinding bits are still OK, brush is bent and therefore it does not clean very well. This is an excellent summary! Paolo -------------------- Disclaimer: all opinions, ideas and information included here are my own,and should not be intended to represent opinion or policy of my employer.
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Jul 2 2009, 02:54 PM
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#10
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Junior Member Group: Members Posts: 90 Joined: 23-February 09 From: Edmonton, Alberta Member No.: 4611 |
Both Spirit and MRO X-band links with the DSN are at the same frequency. The reason was that it was never thought to have both machines alive at the same time. My knowledge of radio communications can be seen here _> . <_ however, I have to ask why they would choose exactly the same freq even given the thought that the rovers wouldn't last. Is the useful X band that tight? Are future missions (ie: MSL) planning for mission overlap? I'd hope given the longevity of some missions (Happy 5th in orbit Cassini!) that there would be a general goal of avoiding such problems |
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Jul 2 2009, 02:56 PM
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#11
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Senior Member Group: Admin Posts: 4763 Joined: 15-March 05 From: Glendale, AZ Member No.: 197 |
You left off:
Rover DRIVERS - Older but wiser, still functioning within normal parameters. Various components subject to balky performance and occasional mood swings, however these conditions were present at launch and deemed to fall within established tolerances. -------------------- If Occam had heard my theory, things would be very different now.
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Jul 2 2009, 03:03 PM
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#12
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Forum Contributor Group: Members Posts: 1372 Joined: 8-February 04 From: North East Florida, USA. Member No.: 11 |
Jay, I would imagine cost was involved.
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Jul 2 2009, 04:07 PM
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Senior Member Group: Members Posts: 4246 Joined: 17-January 05 Member No.: 152 |
Brilliant, Dan!
APXS - ??? The APXS uses curium-244 sources, which have a half-life of just over 18 years. So they should be fine for a few more sols. One other moving part no-one has mentioned is in the Mossbauer. It works by modulating the signal with a periodic Doppler shift, by vibrating the source. It must be working since they're still using it. |
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Jul 2 2009, 04:11 PM
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#14
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Member Group: Members Posts: 293 Joined: 22-September 08 From: Spain Member No.: 4350 |
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Jul 2 2009, 04:27 PM
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#15
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Junior Member Group: Members Posts: 90 Joined: 23-February 09 From: Edmonton, Alberta Member No.: 4611 |
One other moving part no-one has mentioned is in the Mossbauer. It works by modulating the signal with a periodic Doppler shift, by vibrating the source. It must be working since they're still using it. Wasn't it this vibrating mechanism on both these that had an anomaly during cruise which mysteriously fixed itself on landing? |
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