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My February birthday fund-raising campaign for Behind the Black it now over. I sincerely and with deep gratitude thank all those who donated. Without your support I could not keep doing this, not so much because of the need for income to pay the bills, but because it tells me that there are people out there who want me to do this work. For those who did not contribute during the campaign, please consider adding your vote of support to Behind the Black, by giving either a one-time contribution or a regular subscription, in any one of the following ways:


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LightSail-2 completes three-plus year mission, burning up in atmosphere

LightSail-2 sail deployed
LightSail-2, shortly after deployment in 2019.

LightSail-2, an experimental solar sail built by the Planetary Society, finally ended its mission this week, with the test sail burning up in the atmosphere upon re-entry.

LightSail 2 was launched aboard a SpaceX Falcon Heavy rocket in June 2019, settling into an initial orbit at an altitude of around 720 km (450 miles). At that height, the Earth’s atmosphere is still thick enough to create drag, which would threaten to eventually pull the spacecraft down.

But that’s where the plucky little satellite’s special ability came in. Although it’s only the size of a shoebox, LightSail 2 unfurled a big reflective sheet, called a solar sail, about the size of a boxing ring. The idea is that photons from sunlight strike this sail and generate tiny amounts of thrust, allowing the craft to change its orbit.

And LightSail 2 demonstrated this concept beautifully. In three and a half years, the spacecraft completed around 18,000 orbits and traveled 8 million km (5 million miles), adjusting its orbit continuously to keep itself aloft. But all good things must come to an end, and sometime on November 17, drag finally won the tug-of-war and pulled the spacecraft back to Earth.

LightSail-2 was the third time a light sail had been flown in space, with the first, Ikaros, deployed by the Japanese in 2010 and flown in solar orbit through 2012. That mission was successful in using sunlight to accelerate the sail. This was followed by LightSail-1 in 2015. That mission has some communications problems, but eventually succeeded in its main engineering mission by testing the sail deployment system.

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.


  • Lee S

    It’s worth saying this mission was funded entirely by private contributions… The planetary society is a worthy cause to join.

    It had huge problems some years ago… I tried very hard to organise a Swedish member group perhaps 20-15 years back, and support was non existent, and although I gave up on that project, it’s obvious that things have been completely turned around under different management.

    Their weekly podcast is almost essential listening for any space fan, and the monthly report from their space advocate in Washington shows exactly where your.dollars are going.

    I’m not a huge fan of lightsailing… That’s another conversation tho…but the Planetary society is worth throwing a few dollars at, after, of course..BTB!

  • Has not the Planetary Society always opposed manned (personned) spaceflight, maintaining that space should be exploration only?

  • Michael McNeil: Yes, the Planetary Society has always been against manned space exploration, though this position might have softened in recent years.

  • Jason Willingham

    The article doesn’t say when, I saw a pretty spectacular meteor at about 5:20 am that day. I’d guess somewhere over BC, Canada. I wonder if that was it, I’d imagine the thin sail could make for a more showy entry?

  • Jason Willingham: It is unlikely what you saw was Lightsail. See the orbital re-entry track here. Though a more precise landing spot is not known, the track never gets farther north than Mexico.

  • Jason Willingham

    Ah, thanks for the link. Then just a well timed albeit spectacular garden variety meteor.

  • Jason Willingham: FYI, you might have seen the asteroid I reference in a post today:

    Astronomers spot asteroid mere hours before it burned up in Earth’s atmosphere

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