Planet Mappers: Mars FAQ

Got a question? We just might have an answer for you below.

We are working to collect the most frequently asked questions from the forum, blog comments, and your emails all in one place so it is easier for you to find answers and see what others are wondering about.

Got a question? We just might have an answer for you below.

We are working to collect the most frequently asked questions from the forum, blog comments, and your emails all in one place so it is easier for you to find answers and see what others are wondering about.

Why am I identifying craters?

Craters can tell planetary scientists a lot about a surface, such as its age, how thick the soil, what kinds of erosion processes are occurring, and what kinds of material may be on or just under the surface.

To study all these things, we need to know where impact craters are, how many there are, and different things about them. This gives us the basic task: Find craters!


What is Planet Mappers: Mars edition currently studying?

Screen Shot 2015-06-10 at 6.15.03 PM

Planet Mappers: Mars image

Planet Mappers: Mars is packed with two very different data sets that allow you to help with two different science projects. In one data set, you’ll explore diverse landscapes as you hunt down elusive craters on a hunt for those places on Mars where the surface is changing under the force of erosion. Surface materials (translation: dirt) in these regions have spent less time being exposed to the harsh rays of space; high-energy from the Sun and from powerful events throughout our universe can break down fragile molecules, such as large organic molecules. The 2020 rover is being designed to look for these molecules, and you can add to the dataset used to pick its landing site by mapping out craters in areas of interest.

In the second data set, you’ll map the much more desolate slopes of Elysium Mons and its network related smaller volcanoes.  The density of craters in these regions is a direct indicator of how long it has been since the lava last flowed. To quote Robbins, “This work has implications not only for Mars’ heat budget, but also life because active volcanism can provide not only a heat source, but also a chemical gradient that life could take advantage of.” Put simply, we’re asking you to help us answer, when did Mars last have volcanism, and potentially, when were the conditions in these regions last right for life.

What are the specifications of the cameras that took these images?

Weekly Space Hangout Crew Member Bill Wink has kindly gathered all of this data for us over on this page – Mars Mapper Data.


Why do some of the images have long shadows and others hardly have any?

One of the early science questions we’re trying to answer is, what are the effects of sun angle on crater identification? To study this, we need to try to identify craters in the same area at different sun angles. The higher the sun is overhead (high sun angle), the shorter the shadows are going to be. The lower the sun is on the horizon (low sun angle), the longer the shadows are going to be.

For more information, see our Lighting Effects Guide.

dunes as seen in Planet Mappers: Mars ed.

dunes as seen in Planet Mappers: Mars ed.

I keep seeing awesome stuff like dunes and boulder fields. Why aren’t I marking them?

It turns out those are all really awesome things, but they don’t help with the specific science we’re working on. One of our rules here at CosmoQuest is that we only ask you to do tasks that our science team can turn into useful science. Currently, we don’t have scientists seeking additional data, and we don’t want to waste your time asking you to map things we don’t need mapped. (Also, dunes annoyingly move, so that’s also a thing.)


Screen Shot 2015-06-10 at 10.20.36 PMI think I’ve found something weird or interesting. What do I do?

If you want to call attention to a feature, click on the picture icon, and send us a link to the image at 

How do I know if I’m doing anything right? Why can’t I go back and change things?

We make it so that you can’t go back and change your markings once you’ve submitted an image – you’d be spending all your time fine-tuning past results and not moving on to new ones.

The point of crowd-sourcing like this is to have tens of thousands of people looking at everything to get a consensus result, and your marking that may have been 1 pixel off from the average isn’t going to prevent us from getting good science in the long run. In fact, the analysis of Moon Mappers results from our first year show that to be the case!

We also periodically check how every user is doing. At random intervals, a standardized image will appear for you to do. It won’t be marked in any special way, but CosmoQuest Moon Mapper scientists have already identified the craters in it. Once you’ve completed that image and submitted it, we check how you did against the experts.

When we check, we look at how well the crater centers and diameters compare. We then assign a score. We’ll show you both the score and the way the experts identified craters in that image. If the score is low, we’ll ask you to do a second standardized image – we all have bad days. If the second one is low, we’ll ask you to annotate some images where we guide you through.

I don’t see any craters. Seriously, many images in a row – NO CRATERS.

Yup. we know. Pamela got annoyed by this one afternoon. There was this whole, “I JUST WANT TO MARK SOMETHING” thing going on. But, this is Mars. It’s is a world with wind, ice, and a constantly changing surface. This means that while craters are constantly being formed, they are (perhaps even faster) constantly getting erased. This means the more interesting parts of Mars – the active parts we most want to send a rover to, are the parts with no craters. So, when you hit a no-crater image, just go ahead and enjoy the scene and then click that big blue “I’m done” button.

Back to Mapping Mars.