A lot of things can go wrong when you’re working on a thirty-year project. Consider the charter of the systems subcommittee of Breakthrough Starshot, whose mission is to “…ensure that Starshot engineering activities can and will result in a 0.2c mission to Alpha Centauri.” In the hands of the capable Kevin Parkin, the subcommittee has oversight over a systems team that will conduct system engineering, modeling and integration activities.
I call Parkin ‘capable’ but, like so many of the people I dealt with at the recent meetings in San Francisco, he strikes me as flat-out brilliant. He’s also a strategic thinker who knows how to communicate. Parkin’s presentation on how to structure a project as complex as Starshot included classic failure modes of past projects, such as team members working with differing assumptions, a focus on details and not on the whole, and a focus on the whole and not on the details. Any one of these can trip you up. Walk a fine line, in other words, and try to avoid duplication of effort through careful information management and sound communications.
As I took notes, I thought of something Greg Benford said in Dining with Dirac, an account of a dinner that included Stephen Hawking and Paul Dirac, not to mention Martin Rees: “This is an evening to keep your mouth shut.” I kept mine shut and applied myself to typing faster.
Pete Klupar would sound some of the same themes that Parkin did as we met at Moffett Field that morning, noting as well that long projects like these can be in danger of ‘loss of memory’ as the original team is gradually replaced over time. And something that came up at various points in the discussion kept haunting me as I prowled the grounds at Moffett during our breaks, trying to get my daily walk in while I put the meetings in perspective. A big project has to avoid getting locked in too early. The basic assumptions have to be looked at before it’s too late to change them. We’ll be talking about that more in coming days.
Image: The advisory committee at work. From left (facing the camera): Robert Fugate (New Mexico Tech), Jeff Kuhn (University of Hawaii), Jim Benford (Microwave Sciences), Claire Max (UC-Santa Cruz). Facing away from the camera from left, Mason Peck (Cornell), Kelvin Long (i4IS), Bruce Draine (Princeton), Kevin Parkin (Parkin Research) and Greg Benford (UC-Irvine). Geoff Landis (not pictured here) joined in for a time online from NASA Glenn.
Shadow of the Airship
I tried to see the big picture of Starshot as I walked on a break that first afternoon, enjoying the Bay area’s benign climate. Moffett Field is the home of the famous ‘Hangar One,’ an airship hangar built during the Depression era to house the USS Macon. From Building 18, where we worked, the steel girders of the stripped hanger dominate the view (its exterior panels were removed in 2011). Walking near it is an experience of immensity, with a floor covering eight acres, so large that fog used to form near the ceiling. It was impossible to approach it without thinking of the engineering that went into dirigibles.
The great age of airships ended with the death of the Hindenburg in 1937, though it had been presaged by the loss of the hydrogen-filled British airship R101 in 1930. Moffett Field is itself named after Rear Admiral William Moffett, who died aboard the USS Akron, a helium-filled airship, in 1933. Theories abound as to the loss of the Hindenburg, but it’s understood that inert helium is by far the safer gas. You could call the use of hydrogen a systems engineering choice, but in this case it was one forced on designers by the US embargo on helium to Germany.
The point is, you have to look for any factor that can take a project down, no matter the expediency of one choice over another. What Breakthrough Starshot wants to do is so breathtaking that it’s necessary to stand back and remember its parameters. A plan over three decades to design, simulate and experiment, creating a prototype of a craft that can reach another star, and then actually build such a craft after new infusions of capital demands unique flexibility and what the meeting was there to consider, a careful plan for the early going.
Image: Hangar One at Moffett Field, now a skeletal reminder of the era of enormous airships. Technological change can be abrupt and disruptive, reinforcing the challenging nature of long-range planning. How to make sensible choices in the early going is a huge question.
To Reach a Star
One choice that team members seemed comfortable with is the choice of a sail to reach the target star, presumably in the Alpha Centauri system, although not necessarily Proxima Centauri b. Aboard the sail would be a small payload, perhaps the size of a smartphone, perhaps even smaller, that is built around what the project is calling a StarChip. We’re talking a payload that is measured in grams rather than kilograms, using breakthroughs in miniaturization to fold in communications, navigation, cameras, power supply and LED-like ‘thrusters.’
The early discussions have included a sail of about four meters to the side, itself weighing no more than grams. The sail has advantages that place it far above any other propulsion methods available today. Chemical rockets require far too much propellant to even consider a star mission. Fusion is not available. A sail can be placed under a beam of directed energy that drives it, planners hope, to twenty percent of the speed of light. In the initial Starshot concept, that beam of energy comes from a colossal phased array of lasers, to be built in southern latitudes. The Atacama desert of Chile is often mentioned.
A sail pushed to 20 percent of the speed of light could blow past the Alpha Centauri system after about twenty years of flight time, returning data to Earth if a way can be found to do this, presumably through ‘swarm’ technologies that would leverage the fact that Starshot is not one sail but hundreds, perhaps thousands. Multiplying the number of sails offers the kind of redundancy that allows for projected losses through collisions with dust in the interstellar medium. I listened with fascination to Bruce Draine’s thoughts on the ISM. He is, after all, author of Physics of the Interstellar and Intergalactic Medium (Princeton, 2010).
More on that issue later, though the consensus seems to be that sails and payloads can survive the journey, with some losses along the way. As with the entire concept, you can see that there are showstoppers even when we get to the target star. Just how is that data return managed through payloads as tiny as these? Can the beam array also be a receiver? Can the sail itself become an optical element, a receiver as well as a transmitter, on demand?
I’ve gone through the long list of problem areas in these pages before (see Starshot: Concept and Execution). In San Francisco, we also considered the timeline. The systems subcommittee was in place, and separate subcommittees had been formed for both the laser beamer and the sail, with New Mexico Tech’s Robert Fugate in charge ot the former, Jim Benford of the latter. When we weren’t meeting in joint session, I spent my time in the sail committee, wishing I could be in two places at once, but also fascinated by the early plans for simulations and experimental work to follow up what Jim, brother Greg Benford and Chaouki Abdallah had already done on beamed sails some years back. Thanks to them, we already have beamed sail lab data.
Image: Sail pioneers. Jim Benford, right, talks to Greg Matloff. Benford and brother Greg performed early lab work on beamed sails that will now be extended in new directions. Matloff, inspired by Robert Forward, has written numerous papers on sail technologies, beginning with the classic “Solar Sail Starships: The Clipper Ships of the Galaxy” (Journal of the British Interplanetary Society, Vol. 34, pp. 371-380, 1981).
I should also mention that the San Francisco meetings followed two days of Breakthrough Listen discussions, focused on the effort Yuri Milner launched with a $100 million donation to the SETI effort. I wasn’t able to attend these, although we did have a report from members of the SETI community on what they had accomplished. I’ll try to get to that some time this week.
But back to that Starshot timeline. After a discussion of systems drivers — measures of performance, as Pete Klupar explained in his presentation, and tools that show how well a system meets its goals — Klupar projected a roadmap showing a research and development phase lasting roughly eight years, to be followed by a period of ‘sub-scale testing’ that presumably involves construction of a prototype. Construction of the beamer system and sail could, in Klupar’s chart, begin in the early 2030s, with a launch perhaps as early as the mid-2040s. Needless to say, these are estimates and by their nature flexible.
People keep asking me how you can think about building a system that will allow interstellar flight for $100 million, the amount Yuri Milner donated to establish the project. The answer is, you can’t, but the $100 million isn’t for the entire mission. What the systems subcommittee reported on was $100 million for technology analysis and development over a span of five years, to be followed by a prototype that would take the cost up to $1 billion. The lowest estimate I’ve seen for an actual mission with these technologies is $10 billion, leaving future funding issues to be decided, although presumably success in the early going could encourage wealthy philanthropists to repeat Milner’s gesture with money of their own.
I’m running out of time this morning, so I’ll end here. Tomorrow what I want to do is get into the issue of early simulation and testing, as seen through the deliberations of the sail committee. On the final day of our meetings, this time meeting in the hotel rather than at Moffett Field, the sail group began writing a draft of what will become its first RFP — Request for Proposal — a solicitation that involves bidding to fulfill the requirements defined by the committee. More on this, and on how it will affect the first sail experiments, tomorrow.
Oh, to be a mouse in the corner! :)
Quoting from the main article:
“The lowest estimate I’ve seen for an actual mission with these technologies is $10 billion, leaving future funding issues to be decided, although presumably success in the early going could encourage wealthy philanthropists to repeat Milner’s gesture with money of their own.”
This is exactly what I am afraid of. That the space community will once again HOPE that some rich people will step up and fund the Breakthrough Starshot because they will get all excited about flying to the stars just like the space fans do.
Well, it could happen (Mr. Milner is proof of this), but it could also very likely not happen because rich people have this bad habit of not giving their money away unless it will do them lots of good (that’s why they are rich).
So I strongly suggest that some other means of financing be put into place, otherwise we will spend the next fifty years going to meetings discussing even more elaborate interstellar plans and wondering yet again why the non-space types just can’t see how amazing the Universe is and want to explore it like we do.
Remember, the main reason we have not yet sent a probe to Alpha Centauri is not because we lack the technology or the knowledge. We will never leave the Sol system no matter how smart we get otherwise until that key issue is solved.
It wouldn’t surprise me if the DOD fund the expensive laser array, as it has such obvious military applications from planetary defense (Lubin’s idea already presented) to Earth or orbital targets. $10bn for military spending is almost peanuts. DARPA funding might fund any initial R&D, followed by a DOD contract for a deliverable. It seems fairly obvious that any single array need not always be ready for a military use, but rather time could be leased/donated for the short sail acceleration requirements. This is not like many space projects where the hardware must be used designed and used for a designated user only. The Space Shuttle is a good example where both Nasa and the military used part of the fleet for their own purposes (at least initially).
One of favorite methods for orbit debris mitigation is a large ground based laser system.
Orbit deris removal lasers use short pulses to maximize the target temperature. Laser lightsails use cw lasers to minimizes the target temperature.
IMO getting DOD involved is a terrible idea. I think at some point Project Starshot is going to need a very good PR firm (maybe in 5 to 10 years.) Building a powerful laser is going to alarm countries that view the U.S. as a threat to their culture, nationality, economy etc. The entire idea of traveling to the stars may upset various religions (not all of them peaceful.) It may also upset environmentalists worried about the laser array killing birds or just using energy that could go to providing electricity to third world villages. I know I’m rambling here, but there are a lot of medievalists in the world who resent science and fear technological progress. I think all of these issues can be resolved diplomatically, but my point is don’t assume their won’t be objections over the next 50 years to the initiative.
It isn’t clear to me who the funder is regarding the possible objections you raise. Planetary defence from asteroids is a possible use of such powerful lasers, especially space-based ones. However, even this can raise objections in some groups, as Clarke indicates in his novel, The Hammer of God.
Weapons development has always been an issue. If funds are to be sopped up for weapons development, then I would prefer it to be used for dual use technologies rather than single use. For example, I am happier with DOD spending on the X-37B as it is extending space applications development, as well as testing materials to exposure in the space environment and a high power ion drive for manoeuvring. This seems preferable to other areas of defence spending and military procurement.
The military are not famed for their sharing ethic. But let’s hope for an exception. That beamer has to get built somehow.
Paul, was there any quiet discussion, behind the scenes, as to what was going on with the EmDrive or Cannae Drive? Thanks.
Nothing I heard. The sail and beamer concept is what is under study, as we have promising results on that. I didn’t hear anything about these other concepts.
mmm…been thinking, $100 million may be all that is needed. If we where to coat satellites with the very reflective sail material we could use the laser to bring down satellites in a controlled manner for repair and relaunch. All we have to do is slow the craft to below the melting point of the materials used. By carrying out a satellites repair and upgrade process it would reduce the costs to the communication industries considerably. I will stick this in the breakthrough site tomorrow.
During a 28 yr career at LM SSC I have supported a number of programs using ground based, air based or space based high power lasers . The fundamental issue with using high power laser light to accelerate a space sail over long distances will be beam divergence
[see: https://en.wikipedia.org/wiki/Beam_divergence ] [not to mention the MW radiators assuming a 50% efficiency to produce the laser light].
In fact for the GEO orbiting Space Based Solar Power System the most efficient [> 80%] method of power transmission to ground receivers were 5 MHz rf transmitters.
5 MHz?
NASA has a 19 billion annual budget. That budget has orders to look into this project. If it comes in at 10 billion for the greatest trip ever then NASA needs to go away. 10 billion is peanuts to NASA…to DOD it’s a rounding error. Great work Paul..on this Proxima and the signal too.
Ten billion dollars is over half of NASA’s annual budget. How is that amount of money “peanuts” to them?
Quite frankly I do not have a lot of confidence in NASA doing anything serious with an interstellar mission. Just look at their track record trying to get humans to Mars, which has been pushed out to some vague time in the 2030s and no doubt will be pushed even further into the future (literally passing the buck).
If their handling of warp drive “research” is any indication – a $50K budget (K, not M) and one guy writing a white paper and doing some ambiguous tests – that further makes me think they will not play a major role if any in Breakthrough Starshot. But hey, prove me wrong here somebody.
Here’s an example of what NASA does with an interstellar probe mission:
http://interstellarexplorer.jhuapl.edu/mission/implementation.html
Paul, I appreciate your reporting from these events. It is great to read about the progress. I hope they keep going. As others mentioned they will need to get much more money in a few years.
Glad to do this, Matt. Fascinating stuff…
There’s something things that I’ve long wondered about Mr Gilster concerning these conferences that you attend several times a year. One of the questions that I have is – what do these various organizations whose conferences that you go to observe, what RELATIONSHIPS do they bear with RESPECT to one another in terms of what they are attempting to do with regards to interstellar travel ?
In other words, when you go to the conference like that you just came back from, do they have a certain viewpoint they advocate and are always pushing as their principal viewpoint and specialization ?
Also to, was the conference of that you just came back from in San Francisco, was that by invitation only? And if it was why is it not open to the public ? After all, ultimately, the public will be the ones who are asked to foot the bill for these expensive and complicated missions. Isn’t a certain amount of transparency in the interest of these organizations to permit others to assess where this is all heading ? I’m not trying to sound really STRIDENT here, but I’ve noticed that there is a considerable amount of exclusivity practiced by some of these groups you report on, giving them sort of loftiness; that they are above the public (except of course other than when they asked to pay for something) and personally I have found it rather irritating that (in some cases) they practice such closed doors type of secrecy.
Am I being out of line here ? I hope not, because that is not what I am striving to do here, but I do think that some of the observations I made are not without merit.
Could you kindly give me a break down as to what organizations are involved in these things, and specifically what they do ? Would you, Sir, put forward a viewpoint such as I have advocated to be more open and transparent by them ? Explaining that for us to be interested in something, we should at least be advised in some cases as to what it is that we are asking to be signing on to. I hope you’re not going to take offense to my bluntness in stating my opinions, but sometimes, in the past I have asked similar questions in a roundabout way, and I’ve never felt that they have been answered. Thank you.
Charlie, Breakthrough Starshot is privately funded and asks for no public money, so how they conduct their meetings is entirely up to them. These are working meetings among scientists, and they are not intended as public discussions. That said, their intention as stated repeatedly is to make their findings available to the public, which is one reason I have been going there. The other meetings you refer to are 100 Year Starship, Icarus Interstellar and Tennessee Valley Interstellar Workshop. All are open to the public, though due to space limitations it’s best to sign up early.
Like I said previously, Starshot is going to need a good PR firm.
Nitpick: Geoff Landis, not Jeff Landis.
Hey, thanks for noting that. Embarrassing — I know Geoff! Fixed the caption just now.
Just for the record, Mountain View is not in San Francisco. It is in Silicon Valley (Santa Clara County). It is part of the San Francisco Bay Area though; San Francisco Bay is the body of water visible from Moffet Field. :) But it would more accurate to say these meetings are in Silicon Valley rathen San Francisco unless you actually say “San Framcisco Bay Area”. :-)
Will keep that in mind. Am just a tourist in those parts, but it sure is beautiful…
I believe the “show-stopper” for such a probe would be whether you can get a signal back to our blue dot. If you can’t do that within certain mass constraints, then it’s not worth thinking about. I’d concentrate on solving the show-stopper issue.
I live in the neighborhood. Moffett Field is certainly an interesting base with lots of history.
I always thought combining the sails used to get all those Starshot probes to the target system as one giant reflector to transmit the data back to Earth as an elegant idea using technology that is already present on the mission.
I agree transmitting back to Earth will be a major challenge for a spacecraft the size of a smart phone. However, it is my understanding that the plan is to launch hundreds or thousands of these miniature craft in succession. So maybe each craft could serve as a repeater to boost the relatively weak signal of the craft ahead of it and thus relay signals back to Earth.
I think the spacecraft design of this project is flawed. A laser solar sail propulsion system is good. I don’t think there is enough room for a scientific instruments payload that can get a reasonable amount of data from Proxima Centauri no matter what the break through. Interstellar travel should not have a higher value than information. Quantity of probes sacrificing quality and amount of information is what this project looks like to me.
For that reason I think ten million dollars is better spent on a building larger spacecraft with more remote sensing capabilities or even a near Earth space telescope with star shade or interferometer telescope with direct imaging capability of Earth sized exoplanets, polarimetry and infra-red spectroscopy etc. One might get more useful scientific information that way.
The concept for StarShot would be to use the phased laser array as a detector for laser communication from the wafersat back to Earth.
The Brashears et al. study from Philip Lubin’s group (I’ll try to link the PDF below, though it might be automatically removed) shows that a 2 g wafer sat on a 1 m diameter laser sail can send nearly 370 bits/s within a 1-Watt burst from Alpha Centauri back to earth. With 5 mW of on board power (from a tiny RTG), the average data rate back to Earth via these periodic bursts would be 2 bps.
If the sail itself could be used as a modulated mirror to reflect the driving laser light back, then the data return rate could be much, much greater.
Ref:
Brashears, T., Lubin, P., Hughes, G. B., McDonough, K., Arias, S., Lang, A., … & Zhang, Q. (2015, September). Directed energy interstellar propulsion of wafersats. In SPIE Optical Engineering+ Applications (pp. 961609-961609). International Society for Optics and Photonics.
Chicago
http://www.deepspace.ucsb.edu/wp-content/uploads/2015/11/Brashears-etal-SPIE-2015-Interstellar-WaferSats-v07b-comments-removed.pdf
Excuse me, I meant 10 billion dollars
Understand that Geoffrey, and agree with you 100%. Proxima isn’t worth the effort of a starshot at this point. Building the next couple of generations of telescopes which could much better remotely study the Proxima system as well as the 500+ stars within a 10 parsec radius of Sol is much more worthwhile. Frankly, even if it is possible to accelerate a probe to 0.2 c, I just don’t see the point of a flyby which covers an AU every 40 minutes. Think how little we knew about Mars in 1964, despite decades of observations with various large instruments from opposition distances of only 0.5 AU.
Proxima Centauri b is very much worth the effort. Sending spaceships to PCb is how we will learn to fly. It would be worth sending spacecraft there even if we know everything. Telescopes are improving, no doubt we will see a lot from the space telescopes, but I am sure there will be more to learn.
A key part of what we get out of going is just in the going there. Proxima is the first step in what will hopefully be many longer journeys.
https://arxiv.org/abs/0809.3535
The beryllium hollow-body solar sail: exploration of the Sun’s gravitational focus and the inner Oort Cloud
Gregory L. Matloff, Roman Ya. Kezerashvili, Claudio Maccone, Les Johnson
(Submitted on 20 Sep 2008)
Spacecraft kinematics, peak perihelion temperature and space environment effects during solar-radiation-pressure acceleration for a beryllium hollow-body interstellar solar sail inflated with hydrogen fill gas are investigated.
We demonstrate that diffusion is alleviated by an on-board fill gas reserve and electrostatic pressure can be alleviated by increasing perihelion distance. For a 0.1 AU perihelion, a 937 m radius sail with a sail mass of 150 kg and a payload mass of 150 kg, perihelion sail temperature is about 1000 K, peak acceleration is about 0.6 g, and solar-system exit velocity is about 400 km/s. After sail deployments, the craft reaches the 200 AU heliopause in 2.5 years, the Sun’s inner gravitational focus at 550 AU in about 6.5 years and 2,550 AU in 30 years.
The Be hollow-body sail could be applied in the post 2040 time frame to verify general relativity predictions regarding the Sun’s inner gravitational focus and to explore particles and fields in the Sun’s inner Oort Comet Cloud.
Subjects: Space Physics (physics.space-ph); General Physics (physics.gen-ph)
Cite as: arXiv:0809.3535 [physics.space-ph]
(or arXiv:0809.3535v1 [physics.space-ph] for this version)
Submission history
From: Roman Kezerashvili [view email]
[v1] Sat, 20 Sep 2008 22:18:17 GMT (9kb)
https://arxiv.org/pdf/0809.3535v1.pdf
I wrote I like the laser sail propulsion. The problem is with the scientific instruments payload size with the Breakthrough Star shot probe is limited to a cell phone therefore the remote sensing capability must be less than with a larger spacecraft.
We can make a spectrometer that will fits into a cell phone now days but I can’t imagine it would be up to scientific standards for useful information due to the small size of the lens, short focal length etc.
Also an infra red spectrometer and microwave radiometer can’t be put into a cell phone. The microwave radiometer needs a radar dish at least a half a meter in size and the infra red spectrometer needs to be larger also since it has to be able to differentiate between many different frequencies of infra red and a black body from of distance of tens of thousands of kilometers.
I just don’t see an instrument payload the size of a cell phone being capable of getting any useful information from an exoplanet that we cant already achieve with near Earth based measurements. Consequently, I think the plans need to be redesigned for a larger single craft with room for a useful scientific remote sensing payload instead of the novelty of a having thousand cell phones sent to the next solar system.
Here is a job for Breakthrough Starshot, one where many little probes “seeding” the galaxy is the ideal format. This of course assumes that no one else will be around to mind us dropping our DNA upon other worlds and no one else has come up with the same idea to spread their seeds around the Universe.
“The Genesis Project”— Scientists Propose Transplanting Earth Life to Alien Planets
September 02, 2016
Scientists are exploring are proposing transplanting life to planets outside our solar system that are not permanently inhabitable. a Genesis mission could be achieved within a few decades with the aid of interstellar unmanned micro-spacecraft that could be accelerated and slowed down passively.
On arrival, an automated gene laboratory on board the probe would synthesize a selection of single-cell organisms with the aim of establishing an ecosphere of unicellular organisms on the target planet. This could subsequently develop autonomously into complex life forms.
In recent years, the search for exoplanets has identified very different types. “It is therefore certain that we will discover a large number of exoplanets that are inhabitable intermittently but not permanently. Life would, indeed, be possible on these planets, but it would not have the time to grow and develop independently,” says Claudius Gros from the Institute of Theoretical Physics at Goethe University Frankfurt.
“In this way, we could jump the approximately four billion years that had been necessary on Earth to reach the Precambrian stage of development out of which the animal world developed about 500 million years ago,” explains Gros. In order not to endanger any life that might already be present, Genesis probes would only head for uninhabited exoplanets.
The mission’s actual duration played no role in the Genesis project, since the time scales for the subsequent geo-evolutionary development of the target planet lies in the range between a few tens of millions and a hundred million years.
Full article here:
http://www.dailygalaxy.com/my_weblog/2016/09/the-genesis-project-scientists-propose-transplanting-earth-life-to-alien-planets.html
The paper:
Developing Ecospheres on Transiently Habitable Planets: The Genesis Project
Claudius Gros
(Submitted on 22 Aug 2016 (v1), last revised 1 Sep 2016 (this version, v2))
It is often presumed, that life evolves relatively fast on planets with clement conditions, at least in its basic forms, and that extended periods of habitability are subsequently needed for the evolution of higher life forms. Many planets are however expected to be only transiently habitable.
On a large set of otherwise suitable planets life will therefore just not have the time to develop on its own to a complexity level as it did arise on earth with the cambrian explosion.
The equivalent of a cambrian explosion may however have the chance to unfold on transiently habitable planets if it would be possible to fast forward evolution by 3-4 billion years (with respect to terrestrial timescales).
We argue here, that this is indeed possible when seeding the candidate planet with the microbial lifeforms, bacteria and unicellular eukaryotes alike, characterizing earth before the cambrian explosion. An interstellar mission of this kind, denoted the `Genesis project’, could be carried out by a relatively low-cost robotic microcraft equipped with a on-board gene laboratory for the in situ synthesis of the microbes.
We review here our current understanding of the processes determining the timescales shaping the geo-evolution of an earth-like planet, the prospect of finding Genesis candidate planets and selected issues regarding the mission layout. Discussing the ethical aspects connected with a Genesis mission, which would be expressively not for human benefit, we will also touch the risk that a biosphere incompatibility may arise in the wake of an eventual manned exploration of a second earth.
Comments: Astrophysics and Space Science (in press)
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Space Physics (physics.space-ph); Populations and Evolution (q-bio.PE)
Cite as: arXiv:1608.06087 [astro-ph.EP]
(or arXiv:1608.06087v2 [astro-ph.EP] for this version)
Submission history
From: Claudius Gros [view email]
[v1] Mon, 22 Aug 2016 08:49:44 GMT (334kb,D)
[v2] Thu, 1 Sep 2016 12:25:55 GMT (334kb,D)
https://arxiv.org/pdf/1608.06087v2.pdf
Talk is cheap, and so are white papers. Of course it is always nice to see someone, especially those other than just the science fiction realm, thinking outside the box.
How can we get to Proxima Centauri b?
There’s an exoplanet as close to us as one can get. So how will we get there?
By Corey S Powell | Published: Thursday, September 01, 2016
Sometimes it takes a while for the meaning of a new scientific discovery to really sink in. In the case of the planet Proxima Centauri b, announced last week, it may take decades or even centuries to fully grasp the importance of what we have found. You see, this is not just any planet: It is similar to Earth in mass, and it orbits its star in the “habitable zone,” where temperatures could potentially allow the existence of Earthlike bodies of liquid water. Proxima Centauri is not just any star, either: It is the very nearest one after the Sun, and it is a small red orb whose feeble light makes it relatively easy to study the planet close beside it.
The science at stake here is enormous. Proxima Centauri b will surely become the archetype for understanding more distant Earth-size, and possibly Earth-like, planets all across our galaxy. The effort needed to study it will be enormous, too, however. At present the planet cannot even be glimpsed directly through the mightiest telescopes on Earth. Nevertheless, the race is on–a thrilling but maddeningly slow-motion race to bring Proxima Centauri into view, to figure out if it could (or does!) support life, even to visit it with an interstellar probe.
That last goal is the most ambitious; some might call it the most absurd. But the discovery of Proxima Centauri b comes at a propitious time, just as a group of physicists and engineers have been thinking very realistically about how to send a space probe to another star, and to do it within a single human lifetime.
The resulting Breakthrough Starshot concept would use an array of extremely high-power lasers to shoot a beam at a huge, extremely thin reflective sail. Energy from the beam would accelerate the sail (and a miniature probe attached to it) to 1/5 the speed of light, more than 1,000 times faster than anything humans have yet achieved.
Full article here:
http://www.astronomy.com/news/2016/09/how-can-we-get-to-proxima-centauri-b
To quote:
I worked with Philip Lubin of the University of California at Santa Barbara to develop a popular-level summary of how the Starshot would work. You can read about it here. If you want to dig into the more technical details of the project, Lubin also has a much longer paper posted online.
This proposal envisions technology beyond what is available today, but there are no science-fiction elements in it. No warp drive, no wormholes. It is a straight extrapolation from things we know and do right now, just executed on a vastly greater scale—which is broadly similar to where the idea of going to the moon was around 1950. [Destination Moon, anybody? Great film, highly recommended.]
In other words, we don’t know how to build a Starshot yet, but at least we know where to start. If we invested seriously in the project—on the order of $20 billion total, more than the Large Hadron Collider but far less than the International Space Station—and got started right away, Lubin and other researchers guesstimate that we could have the technology ready in three decades. I’ll be more conservative and add another two decades to allow for all the full suite of components: In addition to the phased laser array you need the the energy-collecting sails, the probes themselves, and a “mothership” to carry them into orbit before interstellar launch. Just this week, a group of Starshot planners met at Moffett Field in California to hash out some of the details.
And…
If you tally my numbers, you’ll see that I envision the first probes reaching Proxima Centauri in about 135 years (and then you have to allow another 4.3 years for their signal to get back home). Using much more aggressive assumptions, Lubin suggests that we could get start receiving our first up-close reports on Proxima Centauri b around 2070. Either way it is a very long wait time to make sense of a new discovery, and that assumes both a sustained, focused effort and the successful resolution of a vast number of technical challenges.
Fortunately, this race passes a lot of milestones that are much closer and easier to reach. Even in its early stages, laser-sail technology would be useful for high-speed exploration through the solar system, or for deflecting and maneuvering asteroids. More to the point, there is a whole other race to Proxima Centauri–one that does not require high-power lasers and interstellar travel, one that is underway right now. I’ll talk more about that in my next post.