Leaving Earth cover

In 2019 I obtained from my former publisher the last 30 copies of the now out-of-print hardback of Leaving Earth. I sold about half of these, and with only a handful left in stock I have raised the price. To get your own autographed copy of this rare collector's item please send a $75 check (includes $5 shipping) payable to Robert Zimmerman to

Behind The Black, c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652

I will likely raise the price again when only ten books are left, so buy them now at this price while you still can!

Also available as an inexpensive ebook!

Leaving Earth: Space Stations, Rival Superpowers, and the Quest for Interplanetary Travel, can be purchased as an ebook everywhere for only $3.99 (before discount) at amazon, Barnes & Noble, all ebook vendors, or direct from my ebook publisher, ebookit.


Winner of the 2003 Eugene M. Emme Award of the American Astronautical Society.

"Leaving Earth is one of the best and certainly the most comprehensive summary of our drive into space that I have ever read. It will be invaluable to future scholars because it will tell them how the next chapter of human history opened." -- Arthur C. Clarke

Astronaut Richard Gordon, 88, has died

R.I.P. Astronaut Richard Gordon, who piloted both a Gemini and an Apollo mission in the 1960s, has passed away at 88.

I described one of Gordon’s spacewalks during his Gemini 11 mission in 1966 as follows:

When he opened the hatch, both he and everything unfastened in the capsule was sucked toward space. Pete Conrad had to grab a leg strap on Gordon’s spacesuit to prevent him from drifting away. Later, Conrad had to pull him back using his umbilical cord. The arduous nature of the work caused both Gordon and his spacesuit to overheat, leading him to terminate the firs spacewalk after only 33 minutes.

On Gordon’s second and last flight on Apollo 12 he remained in orbit while Pete Conrad and Alan Bean went down to the surface, the third and fourth humans to walk on another world.

Pioneer cover

From the press release: From the moment he is handed a possibility of making the first alien contact, Saunders Maxwell decides he will do it, even if doing so takes him through hell and back.

Unfortunately, that is exactly where that journey takes him.

The vision that Zimmerman paints of vibrant human colonies on the Moon, Mars, the asteroids, and beyond, indomitably fighting the harsh lifeless environment of space to build new societies, captures perfectly the emerging space race we see today.

He also captures in Pioneer the heart of the human spirit, willing to push forward no matter the odds, no matter the cost. It is that spirit that will make the exploration of the heavens possible, forever, into the never-ending future.

Available everywhere for $3.99 (before discount) at amazon, Barnes & Noble, all ebook vendors, or direct from the ebook publisher, ebookit.


  • wayne

    Gemini 11
    Universal News 1966

  • Edward

    The main purpose of Project Gemini was to learn all that was needed to perform the Apollo missions, including orbital maneuvering, rendezvous, docking, and working outside the spacecraft. Ed White’s excursion did not require any actual work, so he had an easy time of it (perhaps fooling the planners for future missions), but many important lessons were learned from subsequent spacewalks, because it turns out that it is not as easy to work in zero G as one would think. Everything takes longer than in the movies.

    wayne’s video, above, tells about the one-orbit rendezvous of Gemini 11. The reason it was needed for Apollo is because the LEM Ascent Module coming from the lunar surface was going to rendezvous with the Apollo mother ship shortly after lunar launch. Many rendezvous (this is also the plural) took a couple of days or so, but the Russians are now using a “fast Rendezvous” that takes six hours (about 4 orbits).

    For those who are seriously curious, I came across this article, which uses a little humor and very little math, to explain rendezvous.

    Notice that Gemini 11 and/or its Agena target craft would have had to use a “dog-leg” maneuver to get it into the correct orbital plane for rendezvous.

    As an aside, Figure 9 is the kind of thing that we used in my orbital mechanics class to examine rendezvous (a math intensive calculation, using partial differential equations in three dimensions).

  • Judy

    Sorry for the pedantry, but shouldn’t it be “both a Gemini and an Apollo…”?

  • Judy: No apologies required. Pedantry appreciated! My grammar has been fixed.

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