mars

Yesterday we had a look at the track of the Curiosity rover in Google Earth. We noticed that there is some very high resolution imagery of the area. We have previously experimented with getting Mars imagery into Google Earth but did not find any imagery with such high resolution. So we decided to have another look.

It appears that there are multiple orbiters each with multiple imaging systems and each camera is managed by a different organisation. The imagery we looked at previously is from the THEMIS instrument on the orbiter Mars Global Surveyor. It appears that the highest resolution imagery comes form the HiRISE instrument on the same orbiter. We found that it is possible to access the imagery at this website which also allows access to imagery from three other instruments, CTX, MOC and CRISM.

We looked for an image in the location of Curiosity and chose this one. The image is compressed using jp2, similar to Sentinel imagery. We used a tool called Irfanview to convert it to jpg. Since it is quite a large image, we chose to crop it to the location we are interested in. We then placed the image in Google Earth using an image overlay and matched it to the imagery already available.

The image was captured on March 30th, 2016. So, we used Fernando Nogal’s KML track for curiosity that we looked at yesterday to determine where Curiosity was on that date. And sure enough, we can actually see Curiosity!

Curiosity as seen in HiRISE imagery.

This suggests that it may be possible to identify the final resting place of the Schiaparelli lander, which is currently believed to have crash landed, once imagery of its expected landing zone becomes available.

To see the image in Google Earth download this KML file.

With the recent attempted landing on Mars we thought it might be a good time to discuss another Mars inhabitant, NASA’s Curiosity rover.

GEB reader Fernando Nogal let us know about a KML file he maintains which tracks the path of Curiosity on Mars. It can be found in this thread on unmannedspaceflight.com.

Google Mars has a built-in layer showing the locations of various landers and rovers on Mars, including Curiosity and its track. However, the track displayed for Curiosity does not match up with Fernando’s version. A look at the terrain in the imagery shows that Fernando’s version is the more accurate one, as you can clearly see that Curiosity followed certain terrain features to avoid driving over obstacles. This is with the “Rovers and Landers” layer turned on, which includes some HiRISE/CTX imagery. With it turned off, the default Google Mars imagery appears to be out of alignment with both tracks.

We have not been able to identify the source of the Google Mars track, but while trying to find out more about it, we discovered this map which shows yet another version of the track, which is ever further out of alignment.

So what is going on? Our guess is that this is because Mars does not have a GPS system in place and the less accurate tracks are being determined by dead reckoning using Curiosity’s data about the directions and distances it drives whereas Fernando’s track is based on identifying features in the imagery the rover sends back.

If any of our readers knows more about this or where the Google Mars track is sourced from, please let us know in the comments.

Regarding yesterday’s landing attempt, as of this writing it appears that the orbiter managed a successful orbit insertion but the lander’s status is uncertain.

We also came across this interesting article about historical maps of Mars and how our knowledge of the red planet has improved over time. A number of the historical maps can be found in the layer “Mars Gallery->Historic Maps”. It is interesting that older maps had South at the top. Google Earth has a similar layer called “Rumsey Historical Maps” found in the “Gallery” layer that features historical maps of Earth.