Author Topic: Breakthrough Starshot  (Read 79021 times)

Offline rweede

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Re: Breakthrough Starshot
« Reply #140 on: 08/29/2016 08:34 am »
Untrue.  Project Longshot, using nuclear pulse propulsion, did not rely on non-existent or impractical technologies.  And it was developed in the 1980s.

Quoting from the Wikipedia article on the subject:
Quote
Similar to Project Daedalus, Longshot was designed with existing technology in mind, although some development would have been required. For example, the Project Longshot concept assumes "a three-order-of-magnitude leap over current propulsion technology".

"Some development" is quite the understatement. We don't have inertial confinement fusion of the kind of efficiency necessary for Longshot, and we don't have ANY machine that can be expect to keep working for 100 years without any kind of human intervention, much less a 300 kw fission reactor at full blast. So I would say Project Longshot very much relied on technology that does not exist even now, 30 years later.

Regarding the technical difficulties, Breakthrough Starshot seems at least as doable ...

Offline Star One

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Breakthrough Starshot
« Reply #141 on: 08/29/2016 06:44 pm »
First of Paul Gilster's reports from the recent Breakthrough Starshot meeting.

http://www.centauri-dreams.org/?p=36265
« Last Edit: 08/29/2016 06:44 pm by Star One »

Offline as58

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Re: Breakthrough Starshot
« Reply #142 on: 08/29/2016 09:06 pm »
Quoting from the Wikipedia article on the subject:
Quote
Similar to Project Daedalus, Longshot was designed with existing technology in mind, although some development would have been required. For example, the Project Longshot concept assumes "a three-order-of-magnitude leap over current propulsion technology".

"Some development" is quite the understatement. We don't have inertial confinement fusion of the kind of efficiency necessary for Longshot, and we don't have ANY machine that can be expect to keep working for 100 years without any kind of human intervention, much less a 300 kw fission reactor at full blast. So I would say Project Longshot very much relied on technology that does not exist even now, 30 years later.

Regarding the technical difficulties, Breakthrough Starshot seems at least as doable ...

Sorry for being off-topic...

Was Longshot even a real project? The document that every website refers to seems to be written by a group of undergraduates at US Naval Academy for some course(s). IMO, it's not even a particularly good undergraduate research report.

Offline Star One

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Re: Breakthrough Starshot
« Reply #143 on: 08/30/2016 07:28 pm »
Breakthrough Starshot report 2.

http://www.centauri-dreams.org/?p=36277

Offline KelvinZero

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Re: Breakthrough Starshot
« Reply #144 on: 08/31/2016 10:49 pm »
(Sorry haven't read the entire thread. If you know it has already been discussed just say so and I will trawl for it. If you know who by that could help locate it maybe.)

Has there been discussion of the vast range of nearer targets this could apply to? Obviously you would not just run it once and there are hundreds of known dwarf planets and a possible new ninth planet in our solar system that are still well out of practical reach. Perhaps such lasers could have duel uses also such as powering thermal or electric propulsion near earth or a probe far from the sun?

Another possible application of this array: space junk removal?

(I know RobotBeat doesn't like the beamed power idea compared to SEP but I can't remember the issue. Sorry RB.)
« Last Edit: 09/01/2016 01:44 am by KelvinZero »

Offline Robotbeat

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Re: Breakthrough Starshot
« Reply #145 on: 09/03/2016 07:14 pm »
(Sorry haven't read the entire thread. If you know it has already been discussed just say so and I will trawl for it. If you know who by that could help locate it maybe.)

Has there been discussion of the vast range of nearer targets this could apply to? Obviously you would not just run it once and there are hundreds of known dwarf planets and a possible new ninth planet in our solar system that are still well out of practical reach. Perhaps such lasers could have duel uses also such as powering thermal or electric propulsion near earth or a probe far from the sun?

Another possible application of this array: space junk removal?

(I know RobotBeat doesn't like the beamed power idea compared to SEP but I can't remember the issue. Sorry RB.)
Of course we can use it for other trips.

I dislike beamed propulsion when SEP works just as well with a free beamed fusion power source (the Sun). Now interstellar travel is another matter because SEP clearly fails.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Star One

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Re: Breakthrough Starshot
« Reply #146 on: 09/05/2016 04:54 pm »
Another update this time talking sails.

http://www.centauri-dreams.org/?p=36310

Offline Star One

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Re: Breakthrough Starshot
« Reply #147 on: 01/09/2017 07:57 pm »
VLT TO SEARCH FOR PLANETS IN ALPHA CENTAURI SYSTEM

ESO Signs Agreement with Breakthrough Initiatives

ESO has signed an agreement with the Breakthrough Initiatives to adapt the Very Large Telescope instrumentation in Chile to conduct a search for planets in the nearby star system Alpha Centauri. Such planets could be the targets for an eventual launch of miniature space probes by the Breakthrough Starshot initiative.
ESO, represented by the Director General, Tim de Zeeuw, has signed an agreement with the Breakthrough Initiatives, represented by Pete Worden, Chairman of the Breakthrough Prize Foundation and Executive Director of the Breakthrough Initiatives. The agreement provides funds for the VISIR (VLT Imager and Spectrometer for mid-Infrared) instrument, mounted at ESO’s Very Large Telescope (VLT) to be modified in order to greatly enhance its ability to search for potentially habitable planets around Alpha Centauri, the closest stellar system to the Earth. The agreement also provides for telescope time to allow a careful search programme to be conducted in 2019.
The discovery in 2016 of a planet, Proxima b, around Proxima Centauri, the third and faintest star of the Alpha Centauri system, adds even further impetus to this search.
Knowing where the nearest exoplanets are is of paramount interest for Breakthrough Starshot, the research and engineering programme launched in April 2016, which aims to demonstrate proof of concept for ultra-fast light-driven “nanocraft”, laying the foundation for the first launch to Alpha Centauri within a generation.
Detecting a habitable planet is an enormous challenge due to the brightness of the planetary system’s host star, which tends to overwhelm the relatively dim planets. One way to make this easier is to observe in the mid-infrared wavelength range, where the thermal glow from an orbiting planet greatly reduces the brightness gap between it and its host star. But even in the mid-infrared, the star remains millions of times brighter than the planets to be detected, which calls for a dedicated technique to reduce the blinding stellar light.
The existing mid-infrared instrument VISIR on the VLT will provide such performance if it were enhanced to greatly improve the image quality using adaptive optics, and adapted to employ a technique called coronagraphy to reduce the stellar light and thereby reveal the possible signal of potential terrestrial planets. Breakthrough Initiatives will pay for a large fraction of the necessary technologies and development costs for such an experiment, and ESO will provide the required observing capabilities and time.
The new hardware includes an instrument module contracted to Kampf Telescope Optics (KTO), Munich, which will host the wavefront sensor, and a novel detector calibration device. In addition, there are plans for a new coronagraph to be developed jointly by University of Liège (Belgium) and Uppsala University (Sweden).
Detecting and studying potentially habitable planets orbiting other stars will be one of the main scientific goals of the upcoming European Extremely Large Telescope (E-ELT). Although the increased size of the E-ELT will be essential to obtaining an image of a planet at larger distances in the Milky Way, the light collecting power of the VLT is just sufficient to image a planet around the nearest star, Alpha Centauri.
The developments for VISIR will also be beneficial for the future METIS instrument, to be mounted on the E-ELT, as the knowledge gained and proof of concept will be directly transferable. The huge size of the E-ELT should allow METIS to detect and study exoplanets the size of Mars orbiting Alpha Centauri, if they exist, as well as other potentially habitable planets around other nearby stars.
More Information

The Breakthrough Initiatives are a program of scientific and technological exploration founded in 2015 by Internet investor and science philanthropist Yuri Milner to explore the Universe, seek scientific evidence of life beyond Earth, and encourage public debate from a planetary perspective.
Breakthrough Starshot is a $100 million research and engineering program aiming to demonstrate proof of concept for a new technology, enabling ultra-light unmanned space flight at 20% of the speed of light, and to lay the foundations for a flyby mission to Alpha Centauri within a generation.
ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.
Links

Breakthrough Initiative
Photos of the VLT
Contacts

Markus Kasper
ESO
Garching bei München, Germany
Tel: +49 89 3200 6359
Email: [email protected]
Breakthrough Initiatives
Email: [email protected]
Janet Wootten
Rubenstein Communications, Inc.
Tel: +1 212 843 8024
Email: [email protected]
Richard Hook
ESO Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email: [email protected]
Connect with ESO on social media

Offline Star One

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Re: Breakthrough Starshot
« Reply #148 on: 04/19/2017 07:09 pm »
BREAKTHROUGH INITIATIVES TO HOST WORLD-RENOWNED SCIENTISTS AND SCHOLARS IN SUMMIT ON LIFE IN THE UNIVERSE AND SPACE EXPLORATION

Second annual “Breakthrough Discuss” conference held April 20-21 and broadcast on Facebook Live

San Francisco – April 18, 2017 – Breakthrough Initiatives today announced its second annual Breakthrough Discuss scientific conference, which will bring together leading astronomers, engineers, astrobiologists and astrophysicists to advance discussion surrounding recent discoveries of potentially habitable planets in nearby star systems. The conference will take place on Thursday, April 20 and Friday, April 21, at Stanford University.
The two days of discussions will focus on newly discovered Earth-like “exoplanets” in the Alpha Centauri and TRAPPIST-1 planetary systems, and new evidence that these planets could be habitable, as well as their potential as targets for novel methods of space exploration.
Guillem Anglada-Escudé, Queen Mary University of London, and Michaël Gillon, University of Liège, will serve as keynote speakers. Sessions will be chaired by Olivier Guyon, University of Arizona, Jill Tarter, former director of the Center for SETI Research, and Avi Loeb, Harvard University. A full overview of the sessions and panels are listed below.
“In the last 10 months, the world of astronomy has been rocked by discoveries of other planetary systems that look remarkably like our own,” said S. Pete Worden, Executive Director of the Breakthrough Initiatives. “The Breakthrough Discuss conference brings together many of the leading minds to advance the conversation on the potential for life on other worlds and to interrogate the conflicting theories and hypotheses prompted by this new data.”
The two-day event will feature three sessions of 19 presentations and 15 panelists. The first will focus on recent observations of nearby planets, including Proxima b, and new techniques for observing them. The second session will examine the possibility of intelligent life in Earth’s cosmic neighborhood, and recent attempts to search for it with Breakthrough Listen. The third session will assess the significance of the newly-discovered exoplanets for the long-term Breakthrough Starshot endeavor, a program spearheaded by Yuri Milner to develop a practical interstellar space probe.
As the closest known exoplanet, Proxima b is the current primary target for Starshot, which aims to develop the technology to send gram-scale spacecraft travelling at 20 percent the speed of light to Alpha Centauri, some 4.367 light years away. Starshot mission leaders Avi Loeb, Philip Lubin and Zac Manchester will be among the distinguished participants at Breakthrough Discuss.
The conference will be broadcast on Facebook Live at www.Facebook.com/BreakthroughPrize. Viewers are encouraged to join in the conversation and submit questions, which have the opportunity to be answered by the panelists in real-time.
Start times for all sessions will also be posted on the Breakthrough Facebook page. For more information on the program, including a detailed schedule, please visit: breakthroughinitiatives.org/Events.
Breakthrough Discuss is hosted by Stanford University’s Department of Physics and the Harvard-Smithsonian Center for Astrophysics and sponsored by the Breakthrough Initiatives.
Breakthrough Discuss is an annual academic conference focused on life in the Universe and novel ideas for space exploration.
Breakthrough Initiatives are a suite of scientific and technological programs exploring the big questions around life in the Universe, such as, Are we alone? What are the nearest habitable planets? And can we become an interstellar civilization?
For more information see breakthroughinitiatives.org


Offline Star One

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Re: Breakthrough Starshot
« Reply #149 on: 04/20/2017 09:23 pm »
BREAKTHROUGH LISTEN INITIATIVE PUBLISHES INITIAL RESULTS

Analysis results of petabytes of data from the first year of Green Bank Telescope observations made public, including the 11 events ranked highest for significance

San Francisco – April 20, 2017 – Breakthrough Listen – the initiative to find signs of intelligent life in the universe – has released its 11 events ranked highest for significance as well as summary data analysis results. It is considered unlikely that any of these signals originate from artificial extraterrestrial sources, but the search continues. Further, Listen has submitted for publication (available April 20) in a leading astrophysics journal the analysis of 692 stars, comprising all spectral types, observed during its first year of observations with the Green Bank Telescope.
Breakthrough Listen has so far acquired several petabytes of data using the Green Bank Radio Telescope (GBT) in West Virginia, Lick Observatory’s Automated Planet Finder on Mt. Hamilton in California, and the Parkes Radio Telescope in Australia. The Breakthrough Listen science team at the University of California, Berkeley’s SETI Research Center (BSRC) designed and built an analysis pipeline that scans through billions of radio channels in a search for unique signals that might indicate the presence of technology developed by civilizations outside our Solar System.
Initial results from deploying this pipeline on the first year of Breakthrough Listen data taken with the “L-band” receiver at GBT (covering frequencies from 1.1 – 1.9 GHz) have been submitted for publication in one of the world’s leading astronomy journals. Snapshot data has been released for the 11 highest ranked events that rose above the pipeline’s threshold for significance, as well as summary results from the complete analysis. Data is available at breakthroughinitiatives.org/OpenDataSearch, and BSRC Director Andrew Siemion will be on Facebook Live presenting the results at 3:10pm PT this Thursday, April 20 at the Breakthrough Discuss conference.
“With the submission of this paper, the first scientific results from Breakthrough Listen are now available for the world to review,” said Dr. Siemion. Although the search has not yet detected a convincing signal from extraterrestrial intelligence, these are early days. The work that has been completed so far provides a launch pad for deeper and more comprehensive analysis to come.”
The software used for the analysis in these papers has been made available in a github repository1, along with associated documentation2. This enables programmers and machine learning experts (even those with no prior astronomy knowledge) to join the search for artificial signals, by developing increasingly sophisticated algorithms to comb through the datasets that continue to flow not just from GBT, but from the other participating telescopes.
Data Analysis

The basics of searching for signatures of extraterrestrial technology3 are quite simple. Artificial signals can be distinguished from natural processes through features like narrow bandwidth; irregular spectral behavior, pulsing, or modulation patterns; as well as broad-band signals with unusual characteristics. However, human technology emits signals (known as radio frequency interference) similar to the ones being searched for. This means that algorithms must be designed to ensure that signals are coming from a fixed point relative to the stars or other targets being observed, and not from local interferers (including Earth-orbiting satellites).
The Berkeley SETI Research Center Breakthrough Listen science team examined data on 692 stars from the primary target list from GBT, consisting of three five-minute observations per star, interspersed with five-minute observations of a set of secondary targets. By performing an analysis of thresholded frequency channels, as well as a Doppler drift search (for details see: github.com/UCBerkeleySETI/breakthrough/blob/master/GBT/README.md) the pipeline identified channels where radio emission was seen for each target (referred to as “hits”). The pipeline produced millions of hits for the sample as a whole, of which the vast majority are almost certainly radio frequency interference from human technology. Eleven events rose above the pipeline threshold for significance, but further detailed analysis indicates that it is unlikely that any of these signals originate from artificial extraterrestrial sources.
For each star sample, the team searched through the entire database of events, looking for radio channels where events occurred only at one or a small handful of positions on the sky. While these stars have unique radio “fingerprints”, this is by no means convincing evidence that they host planets inhabited by extraterrestrial civilizations. However, the search for signals that are localized on the sky and appear unusual in some way provides an excellent way to select promising targets for follow-up observations.
The BSRC team continues to develop more and more sophisticated algorithms, and plans to release updated analyses of Listen data approximately once every six months. The Berkeley team also seeks continued and expanded engagement with signal processing and machine learning experts to help mine the Breakthrough Listen dataset in the search for evidence of signals from extraterrestrial civilizations.
Project Leadership

http://breakthroughinitiatives.org/News/10

Offline Star One

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Re: Breakthrough Starshot
« Reply #150 on: 04/24/2017 06:42 pm »
Round up of news from the recent Breakthrough conference.

http://www.centauri-dreams.org/?p=37548

Offline Chris Bergin

Re: Breakthrough Starshot
« Reply #151 on: 07/26/2017 03:07 pm »
Presser from their publicity arm:

In Quest to Reach Alpha Centauri, Breakthrough Starshot

Launches World’s Smallest Spacecraft

 

First Prototype ‘Sprites’ – Precursors to Eventual ‘StarChip’ Probes – Achieve Low Earth Orbit

San Francisco – July 26, 2017 – Breakthrough Starshot, a multi-faceted program to develop and launch practical interstellar space missions, successfully flew its first spacecraft -- the smallest ever launched.

On June 23, a number of prototype “Sprites” – the world’s smallest fully functional space probes, built on a single circuit board -- achieved Low Earth Orbit, piggybacking on OHB System AG’s ‘Max Valier’ and ‘Venta’ satellites. The 3.5-by-3.5 centimeter chips weigh just four grams but contain solar panels, computers, sensors, and radios. These vehicles are the next step of a revolution in spacecraft miniaturization that can contribute to the development of centimeter- and gram-scale “StarChips” envisioned by the Breakthrough Starshot project.

The Sprite is the brainchild of Breakthrough Starshot’s Zac Manchester, whose 2011 Kickstarter campaign, “KickSat,” raised the first funds to develop the concept. The Sprites were constructed by researchers at Cornell University and transported into space as secondary payloads by the Max Valier and Venta satellites, the latter built by the Bremen-based OHB System AG, whose generous assistance made the mission possible.

The Sprites remain attached to the satellites.  Communications received from the mission show the Sprite system performing as designed.  The spacecraft are in radio communication with ground stations in California and New York, as well as with amateur radio enthusiasts around the world.  This mission is designed to test how well the Sprites' electronics perform in orbit, and demonstrates their novel radio communication architecture.

Breakthrough Initiatives – including most notably, Breakthrough Starshot and Breakthrough Listen -- are a set of long-term astronomical programs exploring the Universe, seeking scientific evidence of life beyond Earth, and encouraging public debate from a planetary perspective.

 

Breakthrough Starshot, announced on April 12, 2016, by Yuri Milner and Stephen Hawking, is a $100 million research and engineering program aiming to demonstrate proof of concept for light-propelled spacecraft that could fly at 20 percent of light speed and, in just over 20 years after their launch, capture images and other measurements of the exoplanet Proxima b and other planets in our nearest star system, Alpha Centauri.

Breakthrough Starshot | Project Leadership

•       Pete Worden, Executive Director, Breakthrough Initiatives

•       Avi Loeb, Chairman, Breakthrough Starshot Advisory Committee; Harvard University

•       Harry Atwater, Caltech

•       Jim Benford, Microwave Sciences

•       Steven Chu, Nobel Prize winner, Stanford University.

•       Bruce Draine, Princeton University

•       Ann Druyan, Cosmos Studios

•       Freeman Dyson, Princeton Institute of Advanced Study

•       Lou Friedman, Planetary Society, JPL

•       Robert Fugate, Arctelum, LLC, New Mexico Tech

•       Giancarlo Genta, Polytechnic University of Turin

•       Olivier Guyon, University of Arizona

•       Mae Jemison, 100 Year Starship

•       Pete Klupar, Director of Engineering, Breakthrough Starshot

•       Lawrence Krauss, Arizona State University

•       Geoff Landis, SA Glenn Research Center

•       Kelvin Long, Journal of the British Interplanetary Society

•       Philip Lubin, University of California, Santa Barbara

•       Greg Matloff, New York City College of Technology

•       Claire Max, University of California, Santa Cruz

•       Kaya Nobuyuki, Kobe University

•       Kevin Parkin, Parkin Research

•       Mason Peck, Cornell University

•       Saul Perlmutter, Nobel Prize winner, Breakthrough Prize winner, UC Berkeley and Lawrence Berkeley National Laboratory

•       Martin Rees, Astronomer Royal

•       Roald Sagdeev, University of Maryland

•       Ed Turner, Princeton University, NAOJ
« Last Edit: 07/26/2017 03:11 pm by Chris Bergin »
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Offline Chris Bergin

Re: Breakthrough Starshot
« Reply #152 on: 07/26/2017 03:10 pm »
Another e-mail...

I wanted to share the latest development in the  Breakthrough Starshot project -- news breaking today re: their successful launch of the world’s smallest spacecraft probes (“Sprites”), which have achieved low Earth orbit. [See full press release with graphics below.]


"Breakthrough Starshot, the $100 million initiative aiming to send robotic missions to nearby stars by the mid-21st century, has achieved what might prove to be a “Sputnik moment” in successfully lofting its first spacecraft—the smallest ever launched and operated in orbit…

Before they ever reach the stars, [Sprite developer Zac] Manchester says, the Sprites are more likely to first form three-dimensional antennas in deep space to monitor space weather that could threaten Earthly power-grids and orbiting spacecraft. He believes larger interplanetary probes could deploy swarms of Sprites to pepper promising asteroids, moons and planets with sensors seeking out mineral deposits or signs of extraterrestrial life…

 

According to [Breakthrough Initiatives Executive Director Pete] Worden, that would be a powerful new paradigm for space science. “Eventually, every mission that NASA does may carry these sorts of nanocraft to perform various measurements,” he says. “If you’re looking for evidence of life on Mars or anywhere else, for instance, you can afford to use hundreds or thousands of these things—it doesn’t matter that a lot of them might not work perfectly. It’s a revolutionary capability that will open up all sorts of opportunities for exploration.”

 

Please share with your readers, and let me know if you have further questions.
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Offline Star One

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Re: Breakthrough Starshot
« Reply #153 on: 04/01/2018 08:27 pm »

Offline freddo411

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Re: Breakthrough Starshot
« Reply #154 on: 05/12/2020 05:31 am »
Interesting new paper discussing new optimizations for constructing solar or laser driven sails in space.    Re Breakthrough Starshot...

Quote
...Surprisingly, regardless of the material choice, the optimal structures turn out to be simply one-dimensional subwavelength gratings, exhibiting nearly 50% improvement in acceleration distance performance compared to prior studies. ...

https://arxiv.org/abs/2005.04840

Offline Star One

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Re: Breakthrough Starshot
« Reply #155 on: 05/23/2020 08:23 am »
A Starshot Communication Downlink

Breakthrough Starshot is an initiative to propel a sailcraft to Alpha Centauri within the next generation. As the sailcraft transits Alpha Centauri at 0.2 c, it looks for signs of life by imaging planets and gathering other scientific data. After the transit, the 4.1-meter diameter sailcraft downlinks its data to an Earth-based receiver. The present work estimates the raw data rate of a 1.02 {\mu}m, 100 Watt laser that is received at 1.25 {\mu}m by a 30-meter telescope. The telescope receives 288 signal photons per second (-133 dBm) from the sailcraft after accounting for optical gains (+296 dBi), conventional losses (-476 dB), relativistic effects (-3.5 dB), and link margin (-3.0 dB). For this photon-starved Poisson channel with 0.1 nm equivalent noise bandwidth, 90% detector quantum efficiency, 1024-ary PPM modulation, and 10^-3 raw bit error rate, the raw data rate is 260 bit/s (hard-decision) to 1.5 kbit/s (ideal) raw data rate, which is 8-50 Gbit/year. This rate is slowed by noise, especially starlight from Alpha Centauri A scattered into the detector by the atmosphere and receiver optics as sailcraft nears the star. Because this is a flyby mission (the sailcraft does not stop in the Centauri system), the proper motion of Alpha Centauri relative to Earth carries it away from the sailcraft after transit, and the noise subsides over days to weeks. The downlink can resume as soon as a day after transit, starting at 7-22 bit/s and reaching nearly full speed after 4 months. By using a coronagraph on the receiving telescope, full-rate downlink speed could be reached much sooner.

https://arxiv.org/abs/2005.08940

Offline daedalus1

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Re: Breakthrough Starshot
« Reply #156 on: 05/23/2020 08:39 am »
How is the 100 watts for the laser generated? Most of the transmission will be far from the star.
« Last Edit: 05/23/2020 08:40 am by daedalus1 »

Offline ncb1397

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Re: Breakthrough Starshot
« Reply #157 on: 05/23/2020 06:05 pm »
How is the 100 watts for the laser generated? Most of the transmission will be far from the star.

Breakthrough starshot has an article on the power system:
Quote
Battery design is one of the most challenging aspects of the mission. Currently under consideration for the energy source onboard are plutonium-238, which is in common use, or Americium-241. 150mg has been allocated for the mass of the battery. This includes the mass of the radioisotope and the ultra-capacitor. As the isotope decays it will charge the ultra-capacitor. Then, at the appropriate time, the StarChip components will be switched on and begin to operate.
https://breakthroughinitiatives.org/forum/16?page=4

Although this would suggest the power source only generates .02 watts. So, you could run your 100 watt laser for 100 minutes per year. At a data rate of 1500 bits per second, that is only about a megabyte per year. Probably should add photo compression to the research list.
« Last Edit: 05/23/2020 06:19 pm by ncb1397 »

Offline freddo411

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Re: Breakthrough Starshot
« Reply #158 on: 05/23/2020 06:24 pm »
A Starshot Communication Downlink

Breakthrough Starshot is an initiative to propel a sailcraft to Alpha Centauri within the next generation. As the sailcraft transits Alpha Centauri at 0.2 c, it looks for signs of life by imaging planets and gathering other scientific data. After the transit, the 4.1-meter diameter sailcraft downlinks its data to an Earth-based receiver. The present work estimates the raw data rate of a 1.02 {\mu}m, 100 Watt laser that is received at 1.25 {\mu}m by a 30-meter telescope. The telescope receives 288 signal photons per second (-133 dBm) from the sailcraft after accounting for optical gains (+296 dBi), conventional losses (-476 dB), relativistic effects (-3.5 dB), and link margin (-3.0 dB). For this photon-starved Poisson channel with 0.1 nm equivalent noise bandwidth, 90% detector quantum efficiency, 1024-ary PPM modulation, and 10^-3 raw bit error rate, the raw data rate is 260 bit/s (hard-decision) to 1.5 kbit/s (ideal) raw data rate, which is 8-50 Gbit/year. This rate is slowed by noise, especially starlight from Alpha Centauri A scattered into the detector by the atmosphere and receiver optics as sailcraft nears the star. Because this is a flyby mission (the sailcraft does not stop in the Centauri system), the proper motion of Alpha Centauri relative to Earth carries it away from the sailcraft after transit, and the noise subsides over days to weeks. The downlink can resume as soon as a day after transit, starting at 7-22 bit/s and reaching nearly full speed after 4 months. By using a coronagraph on the receiving telescope, full-rate downlink speed could be reached much sooner.

https://arxiv.org/abs/2005.08940

Thanks for sharing this. 

This is the most amazing part of the starshot engineering to me, and I've got an astrophysics degree.    To imagine a chip sized spacecraft being able to send a signal over 4 light years distance is beyond incredible !

288 signal photons per second ... Crazy low!

Offline freddo411

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Re: Breakthrough Starshot
« Reply #159 on: 05/23/2020 06:29 pm »
How is the 100 watts for the laser generated? Most of the transmission will be far from the star.

Breakthrough starshot has an article on the power system:
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Battery design is one of the most challenging aspects of the mission. Currently under consideration for the energy source onboard are plutonium-238, which is in common use, or Americium-241. 150mg has been allocated for the mass of the battery. This includes the mass of the radioisotope and the ultra-capacitor. As the isotope decays it will charge the ultra-capacitor. Then, at the appropriate time, the StarChip components will be switched on and begin to operate.
https://breakthroughinitiatives.org/forum/16?page=4

Although this would suggest the power source only generates .02 watts. So, you could run your 100 watt laser for 100 minutes per year. At a data rate of 1500 bits per second, that is only about a megabyte per year. Probably should add photo compression to the research list.

Great link.

I think you buried the lede.   From the Intro...
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It may be possible to coat the lightsail with a thin film of photovoltaic material, which was demonstrated on the IKAROS mission. This could be extremely useful during approach to the host star. The photovoltaics will be able to supply significant energy when they are within 2AU of the target star. Even with just 10% efficient photovoltaics, the energy supplied would be nearly 2kW at 1AU. This is more than 100,000 times the power of the radioactive energy source, and could conceivably allow much higher data rates for laser communication. This is one option that will be explored.

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