# How tall are the "cliffs of the delta" in the Perseverance rover's landing ellipse?

edit: For all the cliff-doubters in comments, here's a quote of Project Scientist Ken Farley in the new NASA video After the Landing: An Update about NASA’s Perseverance Mars Rover after 01:05:44 (timestamp may degrease after the 31 minutes of leading emptiness is edited out similarly to this)

...and also in the background we believe that we can see the delta; there are features in the back that look like the cliffs of the delta. So when we get those additional images back that Jennifer was mentioning we should know a lot more about that. And we can also see some sand dunes in there...

NASA's Perseverance Rover Landing Ellipse in Jezero Crater shows the 7.7 x 6.6 km ellipse.

The image shows what looks to me like cliffs, and I get that same impression from the screen shot of a NASA animation below as well.

Question: How tall are the steepest features (which look like cliffs to me) within the Perseverance rover's landing ellipse?

Screen shot from Fly Over Mars 2020 Landing Site Jezero Crater in NASA Animation

Cropped from PIA24483:

• There's a pretty decent topographic map here. Perhaps not quite the resolution you're looking for, but it looks like it's maybe ~100m. Feb 14 at 8:18
• From "Sedimentology of the Jezero western fan deposit 1. evidence for a deltaic origin and implications for future exploration":: "Dips range from 0.5-9⁰ and ...." . ( the link didn't work). So these features are certainly no cliffs ! Feb 14 at 16:44
• Regarding your question, can't one consider the part of the delta shown in my answer, as one feature ? You can draw a straight line there on the image from green to white. Feb 15 at 9:05
• The descent stage (flying crane) has good radar altimetry and some crossrange capability, so it should be able to avoid landing (or crashing into) any of the more severe terrain in the landing site. I',m hoping for some very spectacular landscapes even directly after landing and deploy. Feb 15 at 11:51
• @Cornelisinspace No, those are not the cliffs that 'worried' me. THESE are: cdn.cnn.com/cnnnext/dam/assets/… It may just be me being silly, but that angle REALLY looks a bit steeper than "slopes of 30⁰ at most" Mar 6 at 6:45

After carefully cross-referencing the landing ellipse picture with this topographic map provided by ESA, it looks like the cliffs in the center of the ellipse are about 50 meters tall, and no more than 100 meters.

• Would you name that a cliff ? en.wiktionary.org/wiki/cliff#Noun Feb 14 at 12:29
• @Cornelisinspace at least one of the project scientists does (question updated with a quote)
– uhoh
Feb 19 at 2:44

Credit: NASA/JPL/University of Arizona/USGS
Click on the image, and then again for a closer view.

The image above is a part from HiRISE,Digital Terrain Models and shows a colored elevation map of the eastern part of the delta deposit.
(Purple is -2679 m, brown is -2388 m, so a full-scale elevation difference of about 300 m.)
I would say the shaded, south part of the tongue in the middle of the image has one of the steepest slopes, and measured with Mars Trek the smallest horizontal length of the slope there is about 140 m.

Slope of the south part of the tongue, (remarkable detailed) screenshot made with Mars Trek.
The yellow horizontal measured line is 140 m. long.

With the colored bar above it's rather hard to estimate the height but I would guess the slope goes from yellow-brown to reddish-brown.
Then the height could be about 70 m and the steepness of the slope at the south part of this feature would be 27$$^{\circ}$$.