Just as Curiosity was looking like getting-up steam and heading through the Murray Buttes, an anomoly occurs and forces MSL to enter "safe mode". As
the U.S. Geological Survey, Astrogeological Science Center blog post by MSL Co-Investigator, Ken Herkenhoff states:
Early on Sol 1389, the rover experienced a "safe mode event" (SME), apparently due to a software problem that is still not fully understood. So the
3-sol plan did not execute but the rover and all subsystems are healthy. Science planning has been suspended while critical engineering data are
returned to Earth and studied by software experts at JPL. I'm SOWG Chair again today, with not much to do because of the anomaly, but I'm anxiously
following the tactical team's progress in recovering from safe mode.
Now, an SME for a rover or any other space craft is not hugely unusual. The vehicles have in-built mechanisms to properly handle anomolous events that
cause software problems and ensure a safe management of the problem, whatever it may be.
What is strange about this latest SME aboard Curiosity is that even Science Operations Working Group (SOWG) Chair Ken Herkenhoff does not have a clear
understanding of the problem. His use of the wording "apparently due to a software problem that is still not fully understood" implies that the MSL
team believe there is a software problem, and that it is not very well understood.
The hypothecated problem, to my understanding (the one being offered by the investigation team) is of a software mismatch between what the MastCam
readings are and what the internal on-board data predicts it should be. That is the unofficial, official theory at the moment. We have had similar
exploration of theories regading MSL safe mode events. One that comes to mind is when Curiosity's laser pointed at a distant object resulted in vastly
differing distance conclusions than the software model predicted. That was more-or-less resolved by ... ignoring the anomolous data.
So Curiosity became way-laid just as we were becoming excited. As ever, we take a look around.
Here is one picture taken moments before the SME:
Here is the same image:
Our attention was immediately drawn to rock to the left. We took a closer look and were a bit surprised:
Here is the annotated image:
We note two things about the rock/area of the rock:
1. there is an object directly in front of the rock, and
2. there appears to be a face in the rock.
The object of interest in front of the rock has the shape somewhat similar to a hand-held devivce of some sort, perhaps a razor or laser measuring
device. There appears t be a wire leading from the object of interest toward the base of the rock. Lastly, and this is crusial, if you look closely,
there appears, emphasis upon the word "appears", to be a line of something (we postulate a laser or energy ray) exiting from the closest end of the
object of interest. If we follow the direction of the "ray" we note that it directly crosses the path of MSL.
If Curiosity has crossed this ray, we may have an explanation for the SME. We are unsure of what the ray is, as obviously different energy types have
different affects upon metal structures, computer parts, and specifically upon data. It is possible that the "ray", which we think hit one or two
rover wheels (the closest and its opposite on the other side of the vehicle) or steering mechanisms sent an alpha particle pulse into MSL proper,
causing a DRAM failure (this is discussed
in detail, vis-a-vis DRAM problems in
general. Curiosity has multiple RAM types to handle mission needs:
The computer contains special memory to tolerate the extreme radiation environment from space and to safeguard against power-off cycles so the
programs and data will remain and will not accidentally erase when the rover shuts down at night. On-board memory includes 256MB of DRAM and 2 GB of
Flash Memory both with error detection and correction and 256kB of EEPROM. This onboard memory is roughly 8 times as capable as the one onboard the
Mars Exploration Rovers.
Apart from the energy beam zapper device thing sitting on the ground next to the rock,
if we take a look at the rock we get a surprise: what looks like a face. That may be simply pareidolia, but hey, what can we say. If you see it you
see it and cannot be un-seen.
Hopefully the MSL team can get Curiosity up and running soon, and maybe even taker a look at the device closely, and maybe even locate another one
like it, or somehow connected to it.
edit on 9-7-2016 by Babushka because: spelling