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

Trump administration asks Senate to remove SLS requirement for Europa Clipper

The Trump administration has requested the Senate to change the language in its NASA spending bill to remove its requirement that Europa Clipper be launched on SLS.

NASA wants the option to launch the Europa probe using commercial rockets, such as SpaceX’s Falcon Heavy. It also says that there are technical reasons that make using SLS problematic, and worse, the agency simply does not have enough SLS rockets to fly its planned (but unfunded) manned Artemis missions and also launch Europa Clipper.

The House has already removed that requirement in its version of the bill. The Senate has not, probably because the chairman of the Senate Appropriations Committee, Richard Shelby (R-Alabama), is a big fan of SLS (much of it built in his state), and has acted for years to pump money into that project.

If the requirement is not removed, Europa Clipper’s launch will likely be delayed by several years, and cost $1.5 billion more.

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.


  • pzatchok

    This idea will also soon pass.

    One can not live without the other.

  • Edward

    From the article:

    The letter also noted the “under-funding” of NASA’s low Earth orbit (LEO) commercialization efforts, which received only $15 million in the Senate bill versus the $150 million in the agency’s request. That reduced funding, the letter warned, “risks leaving the Nation without a presence in LEO when the International Space Station is eventually retired.”

    That is a scary thought. For a leader in space, this country’s leaders sure aren’t enthusiastic about it. This would make it the third time that our manned presence in space was either non-existent or depended upon others. Between Skylab and the Space Shuttle, we did nothing except a political rendezvous with our rival country, the Apollo-Soyuz “experiment.” From 2011 to this year, we were entirely dependent upon the same rivals for transport to the ISS, which we supposedly lead. Now we soon may not have any space station at all.

    For the past decade, or so, we had expected Bigelow to start a business with their expandable space habitats, but there is serious concern that they will not restart their aerospace business after the Wuhan Flu/Plague Scare From Hell is over. Axiom and Ixion are working on their own versions of space habitats, but they are the ones depending upon NASA’s underfunded commercialization budget to get this done in the 2020s, hopefully before ISS is decommissioned, otherwise we would be left in the blind.

    It looks like Sierra Nevada wants to get into the space habitat business, too.
    From the Dream Chaser article, above:

    Janet Kavandi, the company’s new executive vice president for space systems, showed an illustration of a space station incorporating inflatable modules the company has been developing as part of NASA’s Next Space Technologies for Exploration Partnerships program.

    This is a bit exciting. Now that there are doubts as to whether Bigelow will come back, there seems to be another company preparing to take over this product. How quickly they can do it is a good question.

    I don’t think that SpaceX is the be-all end-all for space exploration (despite its official name), but I do think it will be an important part for the next couple of decades, or so. I expect SpaceX to adapt a version of its manned Starship into a space station. SpaceX will be eager to verify that Starship is capable of long duration missions, and a space station is an excellent way to do this. This would also give a destination, other than the ISS, to Dragon, Starliner, Starship, and other commercial manned spacecraft, such as the crewed version of Dream Chaser. An interesting side effect to using Starship as a space station is its ability for reentry back to Earth in order to perform overhauls.

    I think SpaceX would support other commercial manned space companies to use its space station. Dragon is a short-term objective that helps them with their long term goal of reaching Mars. Starliner and a crewed Dream Chaser are not really the competition for SpaceX’s long-term goal. Having more people on their space station could only help them develop the methods and hardware that they will need for their longer duration Mars missions.

    Those NASA plans foresee a gradual transition by the agency from the ISS to commercial platforms. Lindsey said he expected the ISS to operate to 2028 or 2030, by which time commercial successors like that proposed by SNC will be in place to handle research activities currently done on the ISS.

    The timing of those successors depends upon the funding from Congress. I don’t think that SpaceX wants to be part of a long-term LEO space station solution, but Sierra Nevada wants to join Axiom and Ixion as commercial space station providers.

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