The stars are ours! Scientists using an x-ray telescope installed on ISS have demonstrated it is possible to pinpoint the location of a spaceship and thus navigate through space using pulsars.
In the SEXTANT demonstration that occurred over the Veteran’s Day holiday in 2017, the SEXTANT team selected four millisecond pulsar targets — J0218+4232, B1821-24, J0030+0451, and J0437-4715 — and directed NICER to orient itself so it could detect X-rays within their sweeping beams of light. The millisecond pulsars used by SEXTANT are so stable that their pulse arrival times can be predicted to accuracies of microseconds for years into the future.
During the two-day experiment, the payload generated 78 measurements to get timing data, which the SEXTANT experiment fed into its specially developed onboard algorithms to autonomously stitch together a navigational solution that revealed the location of NICER in its orbit around Earth as a space station payload. The team compared that solution against location data gathered by NICER’s onboard GPS receiver. “For the onboard measurements to be meaningful, we needed to develop a model that predicted the arrival times using ground-based observations provided by our collaborators at radio telescopes around the world,” said Paul Ray, a SEXTANT co-investigator with the U. S. Naval Research Laboratory. “The difference between the measurement and the model prediction is what gives us our navigation information.”
The goal was to demonstrate that the system could locate NICER within a 10-mile radius as the space station sped around Earth at slightly more than 17,500 mph. Within eight hours of starting the experiment on November 9, the system converged on a location within the targeted range of 10 miles and remained well below that threshold for the rest of the experiment, Mitchell said. In fact, “a good portion” of the data showed positions that were accurate to within three miles. “This was much faster than the two weeks we allotted for the experiment,” said SEXTANT System Architect Luke Winternitz, who works at Goddard. “We had indications that our system would work, but the weekend experiment finally demonstrated the system’s ability to work autonomously.”
I think everyone who is interested in interstellar space travel has assumed since the discovery of the first pulsars that they would end up serving as the future north star for interstellar travelers. This experiment shows us how it will be done.
Well read science fiction fans should recognized the literary reference in the tagline.
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.
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.