Here is project manager Pete Theisinger's briefing to reporters in the last hour, describing what has happened:
"At yesterday's press conference, we reported to you that we had had some communications issues with the rover, which we thought at the time was due to weather at the Canberra station and (Deep Space Network) configuration issues.
"We now know we have had a very serious anomaly on the vehicle, and our ability to determine exactly what has happened has been limited by our inability to receive telemetry from the vehicle, basically the last 12 hours or so.
"Let me kind of describe what the sequence of events have been.
"Yesterday afternoon, local solar time on Mars, actually about 1 o'clock, we sent to the vehicle at a command rate of 31.25 bits per second a sequence. We activated that sequence by command and we received a beacon response that indicated that we vehicle had received that sequence and that it was activating that sequence.
"After that time, a scheduled high-gain antenna pass at 2 o'clock in the afternoon, roughly, local solar time on Mars, did not occur.
"The 4:30 p.m. afternoon Mars Odyssey afternoon pass did not occur in the sense there was no indication by Odyssey that they received a UHF transmission.
"Last night, we had about a 1:30-2 a.m. Mars Global Surveyor pass and it was anomalous in the sense that Mars Global Surveyor believes it saw UHF transmission in its receiver telemetry but there was no data in the packets and the period of time that it believed it saw UHF telemetry was very, very short -- about two-and-a-half minutes compared to 12- or 13-minute overflight.
"The 4 a.m. Odyssey pass received no data, and this morning we did not have a direct-to-Earth link session -- we did not receive data on the normal direct-to-Earth session, nor did we receive data on what would have been a fault session at 11 a.m., which is where the spacecraft has entered fault mode, knows that, and chooses to communicate with us at a different time.
"The team has been meeting this morning and through the night working on a set of postulated fault scenarios. There is no one single fault that explains all the observables -- that we know of at the present time that we can conceive.
"We have been working on fault scenarios, we have been developing to-do lists. We have run yesterday's sequences through the test-bed (on Earth) with no anomalous results. So that is kind of our current state of knowledge."
At the end of the news conference, mission manager Jennifer Trosper came into the room and delivered an update to deputy project manager Richard Cook sitting at the briefing desk.
"If the spacecraft believes it's in a fault mode, its command rate should be 7.8 bits per second. We sent a beep today, this morning, about the time that we came down here to talk to you at 7.8. We sent a command that says if you get this send us a beep. And I'm told from Richard that Jennifer came down here to tell us that they think they got it," Theisinger said.
"That would tell us that the spacecraft thinks it's in the fault side of the tree some how for some reason. That would mean that we've got positive power, some elements of the software is working, once again the X-band system is working, the SSPA, the multi-space transponder, all that stuff is working so that would be more information -- good news. We need to confirm that. Data off the DSN sometimes needs double-checking. We'll let you know if that's for sure."
