Scroll down to read this post.


On February 5, 2023 I will celebrate my 70th birthday. Yay! As I do every year during this birthday month, I run a campaign to raise money to support my work here at Behind The Black. I do not run ads. My only support comes from my readers, which leaves me utterly free to speak my mind openly about space, culture, and politics. Please consider supporting me in this work by giving either a one-time contribution or a regular subscription, in any one of the following ways:


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. Donate through Gabpay, using my email address zimmerman @ nasw dot org.

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

4. 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

More delays for SLS?

According to a report today at Ars Technica, there is an engine issue with the SLS rocket presently being prepared for a February unmanned test flight that could delay the launch for months.

The info is buried at the very bottom of the article:

There’s an issue with an SLS engine controller. This past weekend, rumors emerged about a problem with the controller for one of the four RS-25 engines that power the Space Launch System. NASA has not officially commented, but Aviation Week’s Irene Klotz spoke with Aerojet’s RS-25 program manager, Jeff Zotti. Troubleshooting the problem began on November 22, Aviation Week reported.

Schedule impacts yet to be determined … If necessary, “replacing a line or a component … we’re probably talking about multiple days. Replacing an engine, we’re probably talking about multiple weeks,” Zotti told the publication. “On top of that, we have to assess what that does and how that affects the vehicle and the integration activities that are going on,” he added. All of that must be factored into a potential delay of the launch, presently scheduled for February 12. A summer launch for the SLS now seems far more likely than spring.

Any delay beyond March poses a very serious and complex problem. The solid rocket strap-ons have a one year life expectancy once stacked, and both were initially stacked about a year ago. The February launch pushes that life span somewhat. A longer delay is more than can be waived.

Conscious Choice cover

Now available in hardback and paperback as well as ebook!


From the press release: In this ground-breaking new history of early America, historian Robert Zimmerman not only exposes the lie behind The New York Times 1619 Project that falsely claims slavery is central to the history of the United States, he also provides profound lessons about the nature of human societies, lessons important for Americans today as well as for all future settlers on Mars and elsewhere in space.

Conscious Choice: The origins of slavery in America and why it matters today and for our future in outer space, is a riveting page-turning story that documents how slavery slowly became pervasive in the southern British colonies of North America, colonies founded by a people and culture that not only did not allow slavery but in every way were hostile to the practice.  
Conscious Choice does more however. In telling the tragic history of the Virginia colony and the rise of slavery there, Zimmerman lays out the proper path for creating healthy societies in places like the Moon and Mars.


“Zimmerman’s ground-breaking history provides every future generation the basic framework for establishing new societies on other worlds. We would be wise to heed what he says.” —Robert Zubrin, founder of founder of the Mars Society.


All editions are available at Amazon, Barnes & Noble, and all book vendors, with the ebook priced at $5.99 before discount. The ebook can also be purchased direct from my ebook publisher, ebookit, in which case you don't support the big tech companies and I get a bigger cut much sooner.


Autographed printed copies are also available at discount directly from me (hardback $24.95; paperback $14.95; Shipping cost for either: $5.00). Just email me at zimmerman @ nasw dot org.


  • Robbie

    I wonder if NASA insisted that the Starship launch pad now being constructed at the Cape was out of sight from all SLS press areas. Could be embarrassing to see an in-construction tower in the background of first SLS launch and it’s leaning tower that will be scrapped soon after.

  • Richard M

    Eric Berger actually fielded a question about that three days ago on Twitter. He says his sources indicate that NASA can go as late as July on the SRB stacking. If that’s true, they have a bit of margin to play with. But they really can’t afford too much more in the way of delays. And not just because the weather at the Cape gets dodgier the deeper you get into spring.

  • geoffc

    Man, if state of the art SLS needs weeks to change an engine, clearly Starship/SuperHeavy are going to be impossible. I mean 29/33 engines (SH) or 6 engines (Starship) it would take years to simply install them all.

    If NASA can’t do it, obviously, no one can. Alas.

    I fear for our future.

    (For reference, SpaceX install 29 engines in 14 hours, now not fair, since they did not connect everything, it was for a photo op, but still).

  • Jason Lewis

    SLS = Senate Launch System

  • What goes wrong with the boosters? Some sort of internal chemical reaction that makes them what? Unstable-er? Less efficent? Thanks.

  • Jeff Wright

    Everybody seems to be having engine problems-this a black box…Musk and others need to check for sabotage…these were tested at Stennis.

  • George C

    How old are those engine? Not the design, the actual engines. 30 years? After a full system, full power, full duration test, what could go wrong? Maybe the brand new parts aren’t as good as the old ones?
    Meanwhile Rocket Labs announced yet another fresh designed CH4 O2 engine, with a gas generator cycle that it will start testing next year.

    Ah the tragedy of sunk cost obsession

  • Call Me Ishmael

    “What goes wrong with the boosters?”

    “Solid” propellant isn’t actually all that solid. After a year or so of standing on end, it begins to physically slump.

  • wayne

    “Something Wonderful Will Happen”
    2010 The Year We Make Contact

  • Rocket science is hard. But why do private entities make it look easier, while public entitles make it look difficult?

    That’s almost a rhetorical question.

  • David M. Cook

    I fired an AeroTech “White Lightning” composite motor after 20 or more years of sitting around my garage, and it worked fine! No slumping or surface changes were seen. I‘m sure they have plenty of margin for error here.

  • Ray Van Dune

    Increasing the linear size of a similarly-compounded engine would increase the mass by the cube, so there could be substantial differences in the stability of the two.

  • pzatchok

    Nothing is truly solid.

  • Rod

    Back in the day…in graduate aerospace engineering…I took a class in viscoelasticity. I called it everything you wanted to know about creep. Anyway, one of the example problems dealt with solid rocket propellant deformation. Of course, that dealt with missiles that sat in their silos for extended periods. And the greater the missiles diameter, the quicker the deformation.

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 *