Scroll down to read this post.


Please consider supporting my work, as I take no advertisements nor accept any sponsors in order to keep the website clean, easy to read, and to avoid any accusations of conflict of interest. Your support leaves me entirely independent, able to say whatever I think while being free from censorship or reprisals.


You can support me either by giving a one-time contribution or a regular subscription. There are five ways of doing so:


1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.


2. Patreon: Go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation.

3. A Paypal Donation:

4. A Paypal subscription:

5. Donate by check, payable to Robert Zimmerman and mailed to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652

For the 4th time Curiosity’s drill fails to penetrate marker layer

Failed drillhole by Curiosity in marker layer
Click for original image.

For the fourth time this past weekend Curiosity’s drill was unable to penetrate the hard rock of what scientists have labeled “the marker layer”, a distinct feature seen at approximately the same elevation at many places on the flanks of Mount Sharp on Mars.

The image to the right, cropped and reduced to post here, shows that the drill was once again only able to drill a eighth to a quarter inch, not enough to gather samples for testing.

This was our fourth attempt to drill this marker band, and we gave it our best shot from both a geology and engineering perspective. Unfortunately these rocks do not want to cooperate – they’re hard and they weather into resistant and recessive beds which make them very challenging to drill. So the team made the difficult decision to get back on the road, without a drill sample from this location

Overview map
Click for interactive map.

The rover was then programmed to travel about 300 feet south to another spot on the marker layer. This new location is indicated by the blue dot on the map to the right.

Whether the science team will make another attempt to drill into this tough geological layer, indicated by the arrows on the overview map, is not clear at the moment, as the rover is now only a short distance from the southern edge of the layer. From here it could quickly climb up, continuing its journey along its planned route (as indicated by the red dotted line). I suspect, however, if the science team sees a good flat spot conducive to drilling at this location they will try again. The marker layer was one of the mission’s long term major geological targets prior to launch, and to leave it without at least one drill success would be a great disappointment.

The Curiosity team however has generally shown perseverance in these drill efforts. When Curiosity had similar drill issues as it crossed Vera Rubin ridge, the team tried and failed several times to drill, moved on off of the ridge, and then when they had another opportunity to drive downhill again to try again, they did so, finally achieving success. I suspect this determined spirit will compel them to apply the same determination here.

Genesis cover

On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.

The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.

The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.

"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News


  • pzatchok

    I can not wait until we get a real AI tool up there.
    Like a real human.

  • Philip L horner

    That’s not a carbide drill bit?

  • Col Beausabre

    Weighs too much or costs too much…..I know, on a billion dollar mission….

  • Chris

    I seem to remember some experimentation where rocks were made much harder by baking the water out of them. I searched the web looking for data on this but to no avail.

    Ring any bells?

  • pzatchok

    Its not the hardness of the rock.
    I have used a coring drill do drill through large quartz rocks used as aggregate in cement. Took forever but it worked.

    The problem here is that the drill is on a long arm and gets no leverage. In fact I am not even sure if its own weight is allowed to push on the drill head.

  • Star Bird

    They didn.t sharpen it

Readers: the rules for commenting!


No registration is required. I welcome all opinions, even those that strongly criticize my commentary.


However, name-calling and obscenities will not be tolerated. First time offenders who are new to the site will be warned. Second time offenders or first time offenders who have been here awhile will be suspended for a week. After that, I will ban you. Period.


Note also that first time commenters as well as any comment with more than one link will be placed in moderation for my approval. Be patient, I will get to it.

Leave a Reply

Your email address will not be published. Required fields are marked *