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Apr 4 2005, 02:38 PM
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#1
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Junior Member Group: Members Posts: 90 Joined: 13-January 05 Member No.: 143 |
I just heard that Odyssey went into safe mode on Saturday. I haven't seen any official announcement yet.
One result is that MER is having to replan using direct to earth only. Current estimate is that Odyssey will not be able to support UHF relay until "mid-week at the earliest". |
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Apr 4 2005, 02:55 PM
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#2
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Founder Group: Chairman Posts: 14432 Joined: 8-February 04 Member No.: 1 |
Now that's bad news. I suppose they could bring MGS back into a relay role, but it would take about as long to write and uplink the commands for that as it will to fix odyssey - any URL's with news on this?
Doug |
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Apr 4 2005, 03:25 PM
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#3
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Forum Contributor Group: Members Posts: 1372 Joined: 8-February 04 From: North East Florida, USA. Member No.: 11 |
I was wondering why there were no new images since the 2nd April.
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Guest_Sunspot_* |
Apr 4 2005, 04:03 PM
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#4
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Are they still able to command the rovers in the normal way, just not transmit large amounts of data? I suppose they've put off all driving and science activities until the problem is resolved?
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Apr 4 2005, 04:18 PM
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#5
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Member Group: Members Posts: 578 Joined: 5-November 04 From: Denmark Member No.: 107 |
QUOTE (Sunspot @ Apr 4 2005, 04:03 PM) Are they still able to command the rovers in the normal way, just not transmit large amounts of data? I suppose they've put off all driving and science activities until the problem is resolved? Why should they do that? Just send commands and downlink via direct to Earth sessions. And Why has MGS not been used for relay as much as Odessey? -------------------- "I want to make as many people as possible feel like they are part of this adventure. We are going to give everybody a sense of what exploring the surface of another world is really like"
- Steven Squyres |
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Apr 4 2005, 04:21 PM
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#6
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Founder Group: Chairman Posts: 14432 Joined: 8-February 04 Member No.: 1 |
A typical rover day - roughtly - in local solar time....
10:00 - Wakeup 11:00 - Direct from Earth HGA uplink of days commands 11:30 - 5 min carrier only tone on LGA to confirm handover to new sequence (if driving at the same time, this is called a honk - and no, they've not observed a dopler from the rover driving ) 11:40 - Sometimes a nap for a half an hour, or an hour. 15:00 - Sometimes an Odyssey Pass 16:00 - Sometimes an Odyssey Pass - usually one, sometimes 2 - about 90 mins apart 17:00 - Sleep if deep sleep -thenskip straight thru to the following morning, otherwise 03:00 - 04:00 - same UHF as before, one or two, about 90 mins apart. The bulk of the rovers activities occur between around 11:00 and 15:00. Very VERY little data gets downlinked via DTE on the HGA usually - as it's power inefficient compared to UHF ( on a Whrs / Mbit scale ) I imagine, without UHF passes - they might use an extended HGA pass in the morning and add some DTE after the uplink - and perhaps another short one in the afternoon to downlink housekeeping data for the day, and a very small ammount of science data - probably little more than thumbnails, and reduced navcam frames. Doug |
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Guest_Sunspot_* |
Apr 4 2005, 04:48 PM
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#7
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I think they were planning 2 days of imaging at Viking Crater...did that get all the imaging data down?
The lack of any picture updates, even small thumbnails might imply they've decided to forgo any driving/science at the moment? |
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Apr 4 2005, 04:51 PM
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#8
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Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
QUOTE (dot.dk @ Apr 4 2005, 04:18 PM) QUOTE (Sunspot @ Apr 4 2005, 04:03 PM) Are they still able to command the rovers in the normal way, just not transmit large amounts of data? I suppose they've put off all driving and science activities until the problem is resolved? Why should they do that? Just send commands and downlink via direct to Earth sessions. And Why has MGS not been used for relay as much as Odessey? Because the data volume that MGS can store and relay is a pittance compared to Odyssey. -------------------- |
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Apr 4 2005, 05:01 PM
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#9
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Member Group: Members Posts: 578 Joined: 5-November 04 From: Denmark Member No.: 107 |
Can't wait for relay via MRO then hehe
-------------------- "I want to make as many people as possible feel like they are part of this adventure. We are going to give everybody a sense of what exploring the surface of another world is really like"
- Steven Squyres |
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Apr 4 2005, 06:22 PM
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#10
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Founder Group: Chairman Posts: 14432 Joined: 8-February 04 Member No.: 1 |
QUOTE (dot.dk @ Apr 4 2005, 04:18 PM) downlink via direct to Earth sessions. One 12 minute UHF pass with Odyssey = 184 Mbits Typically done 2 times per sol, call it 300 Mbits. 300 Mbits at 8kbps DTE (on DSN antennae already scheduled for other missions) = 10.4 hrs. The most they could use the DTE for in a sol is a couple of hours, it takes a lot of power, and means that a single sols data would take perhaps 4 sols to downlink - during which time, the flash memory will have filled up - two fold MGS uses the MOC buffer for UHF ops - and so it plays hell with scheduling of MGS ops - has to be planned quite well in advance. Odyssey was doing more than enough for relay ops - so MGS was turned back to mapping ops. They only uplink to MGS about 3 or 4 times a week - and the sequence to include fill-in UHF passes would take a week or so to write - so by the time they've written the sequences, uplinked them....Odyssey will be back on course Doug |
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Apr 4 2005, 06:44 PM
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#11
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Junior Member Group: Members Posts: 90 Joined: 13-January 05 Member No.: 143 |
QUOTE (djellison @ Apr 4 2005, 04:21 PM) The bulk of the rovers activities occur between around 11:00 and 15:00. Very VERY little data gets downlinked via DTE on the HGA usually - as it's power inefficient compared to UHF ( on a Whrs / Mbit scale ) I imagine, without UHF passes - they might use an extended HGA pass in the morning and add some DTE after the uplink - and perhaps another short one in the afternoon to downlink housekeeping data for the day, and a very small ammount of science data - probably little more than thumbnails, and reduced navcam frames. Doug Yes, the plan for the next few sols is to convert the morning 20-minute DTE to a 90-minute DTE. This only gives them 12.7 Mbits of downlink, of which the first 7 is engineering data. It also requires them to plan in restricted mode (relying on the previous morning's knowledge). Since the hope is to get Odyssey relays restarted by the end of Wednesday, it doesn't make sense (yet) to try to get an MGS relay going. And no, I haven't found a URL to confirm this information. |
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Apr 4 2005, 07:10 PM
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#12
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Senior Member Group: Members Posts: 3419 Joined: 9-February 04 From: Minneapolis, MN, USA Member No.: 15 |
QUOTE (djellison @ Apr 4 2005, 12:22 PM) QUOTE (dot.dk @ Apr 4 2005, 04:18 PM) downlink via direct to Earth sessions. One 12 minute UHF pass with Odyssey = 184 Mbits Typically done 2 times per sol, call it 300 Mbits. 300 Mbits at 8kbps DTE (on DSN antennae already scheduled for other missions) = 10.4 hrs. The most they could use the DTE for in a sol is a couple of hours, it takes a lot of power, and means that a single sols data would take perhaps 4 sols to downlink - during which time, the flash memory will have filled up - two fold MGS uses the MOC buffer for UHF ops - and so it plays hell with scheduling of MGS ops - has to be planned quite well in advance. Odyssey was doing more than enough for relay ops - so MGS was turned back to mapping ops. They only uplink to MGS about 3 or 4 times a week - and the sequence to include fill-in UHF passes would take a week or so to write - so by the time they've written the sequences, uplinked them....Odyssey will be back on course Doug Makes you appreciate why Squyres, in one Q&A session, said that his number one priority for "what to do different" on future missions is to have a bigger pipe for getting data back to Earth. Heck -- my cable modem provides me 5 Megabits per *second*. At that rate, I can download 300 Megabits in about one minute. How much coax cable would it take to set up the MERs with RoadRunner service, anyway...? -the other Doug -------------------- “The trouble ain't that there is too many fools, but that the lightning ain't distributed right.” -Mark Twain
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Apr 4 2005, 07:26 PM
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#13
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Member Group: Members Posts: 133 Joined: 29-January 05 Member No.: 161 |
QUOTE (dvandorn @ Apr 4 2005, 07:10 PM) Heck -- my cable modem provides me 5 Megabits per *second*. At that rate, I can download 300 Megabits in about one minute. How much coax cable would it take to set up the MERs with RoadRunner service, anyway...? About three times as much as it needs at conjunction Make sure you get the heavy duty cable, it gets quite hot near the middle or use a longer run and route via Venus. tip: twisted pair would be cheaper and lighter than coax and still work at 5 mb/s but it will need more repeaters to boost the signal. -------------------- |
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Apr 4 2005, 07:28 PM
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#14
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Member Group: Members Posts: 578 Joined: 5-November 04 From: Denmark Member No.: 107 |
IF Odessey is crippled could they use Mars Express as a temporary solution?
I know it has relayed a few pictures, but can it relay as much as Odessey? -------------------- "I want to make as many people as possible feel like they are part of this adventure. We are going to give everybody a sense of what exploring the surface of another world is really like"
- Steven Squyres |
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Apr 4 2005, 07:28 PM
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#15
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Founder Group: Chairman Posts: 14432 Joined: 8-February 04 Member No.: 1 |
I'll hold one end - and you start walking, stop when I give it two tugs so I can tie the next reel on, then get going when I give it three tugs.
That - or wait for MRO- with it's 4mbps downlink I think MEX is about as able as Odyssey - and it would be a nice repayment of the Odyssey-Beagle 2 attempts - if Odyssey takes a few days longer that would be a very good idea - but with MARSIS antenna deployment due soon - would they be up for it? Doug |
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