The following is a summary of my notes from a Spirit rover update teleconference today. I hope it is of interest to some of you. For those with snide comments, please take them to the next thread down the hall, as I'm not in the mood.
David Erbas-White
notes from teleconference.:
Here are some items of information from Spirit rover update teleconference with JPL this afternoon. The information was provided directly by Dr. Mark Adler, Spirit mission manager, who fully answered all questions posed by those present.
Please be aware that the following is from my notes, and may not be complete. If you have further questions on Spirit, pose them, as they may jog my memory further ().
Sol 20 (Martian day 20) has been completed with Spirit, and many positive steps were made. JPL tried to establish communication with the rover and query it for its 'health' status, and this succeeded. The 'status frame' is a few thousand bits of information, that were transmitted via the low-gain antenna to earth, and were repeated over a twenty-minute period. The bit rate for this transfer is 120 bits per second.
This is not full health status, but a partial status, as they don't want to do too much until more diagnostic work is done. It is expected that about 73 megabits of information (containing much more in-depth health status) has been transmitted to Mars Odyssey, which will retransmit the information to earth. Some of this information has already been received, and it is being evaluated.
JPL does not currently have complete control of the vehicle. It is apparent (this is an assumption) that the rover has been continuously on for the last few days, which has led to a very rapid depletion of the batteries. They have been so far unsuccessful in getting the rover to 'sleep' so that it can conserve battery power. It is estimated that IF the present drain rate continues, there is 3-4 days of power left, HOWEVER there are positive indications that show that they are getting slightly more control over this problem, and all efforts are being made to proceed.
The rover goes completely to sleep 3-4 times each 'sol', and does a cold-boot each time it wakes up (not a warm boot). What is currently happening appears to be that during the power-down sequence, something is going wrong, and the system resets itself during that power-down sequence, so it is in somewhat of an endless loop. There is some amount of 'watchdog timer' circuitry in place, so it is not a completely continuous reboot/reset sequence, but it does this at intervals. At last report, they were able to get somewhat farther in the shutdown sequence than had previously been done, so they ARE making progress at solving the problems.
The major concern at this point is that they must maintain some battery power in order to keep the heaters running during the Martian night. The heaters prevent certain critical elements from getting too cold, which will cause failure of the vehicle. There is little to no redundancy in many of these areas, and it is unknown as to whether or not the rover would experience critical failure after (for example) the first night without the heaters, or whether this would occur over subsequent days. Thus, the major thrust is to find and fix the problem before battery drain becomes critical.
The upcoming landing of Opportunity presents a problem for the team in that there are both human and equipment logistical problems, such as communications, etc. The team will be switching priorities to Opportunity to assure a safe landing, then will get it as quickly as possible into a 'safe' mode and shut it down, and then switch priority back to Spirit. This is because of the (remote) possibility that the problem in Spirit is systemic, so that if it might affect Opportunity, they want to fix it on Spirit before any problems arise on Opportunity.
At this time Opportunity is fully on target, no further trajectory corrections are anticipated, but it has been programmed to open its chute at a slightly lower altitude than Spirit due to data returned during Spirit's entry into the Mars atmosphere.
The Mars Odyssey spacecraft has been re-programmed to NOT contact Spirit at this time (as it normally would) because this action would 'wake up' Spirit if they manage to get it to sleep, and they need to fully charge the batteries before resuming normal operations.
The high-gain antenna appears to be working properly, and it is not seen as any source of the current problems with Spirit. The initial current anomalies that were measured appear to be due to contaminants (most likely Martian dust) in certain areas of the mechanism, that cleared up after first run-through of full operational travel. At this point in time there is no anticipation of problems with the high-gain antenna itself, but until the power issues are resolved, it will not be used (due to power required for the antenna to track Earth).
There does not appear to be ANY correlation with the problems to the past coronal mass ejection event, and Opportunity did not appear to be affected either. The computers on board the rover are not expected to be affected by any static discharge in the Martian soil, as they are very well isolated in their own Faraday cage in the rover.
It is not currently known if the problem with powering-down the rover is hardware or software related, the anomaly team is seeking to resolve this issue.
It is not anticipated that winds at the site are any problem for the rover. The landing site can reach peak winds of 50 MPH, but has been generally in the 20-30 MPH range since landing. Even winds of
100-200MPH would not be an issue for the rover because of the much lower pressure of the Martian atmosphere.Although there has been a great deal of information gathered by the rover, and the science team has reams of data to go through, at this point they have not reached mission success objectives, so all efforts are being put forth to revive/repair the rover.