Space and astronomy news
Is it time for space lasers yet? Almost.
As time passes, ideas that were once confined to the realm of science fiction become more realistic. It’s true of things like using robots to explore other worlds. Space lasers are a well-used element in science fiction, and we’re approaching the time when they could become a reality.
Where would we put them, and what could we use them for?
Continue reading “There are Plenty of Uses for Powerful Lasers in Space. But Where Should We Put Them?”
Back in April, Russian billionaire Yuri Milner and famed cosmologist Stephen Hawking unveiled Project Starshot. As the latest venture by Breakthrough Initiatives, Starshot was conceived with the aims of sending a tiny spacecraft to the neighboring star system Alpha Centauri in the coming decades.
Relying on a sail that would be driven up to relativistic speeds by lasers, this craft would theoretically be capable of making the journey is just 20 years. Naturally, this project has attracted its fair share of detractors. While the idea of sending a star ship to another star system in our lifetime is certainly appealing, it presents numerous challenges.
Not one to shy away from any potential problems, Breakthrough Starshot has begun funding the necessary research to make sure that their concept will work. The results of their first research effort appeared recently in arXiv, in a study titled “The interaction of relativistic spacecrafts with the interstellar medium“.
Assessing the risks of interstellar travel, this paper addresses the greatest threat where relativistic speed is concerned: catastrophic collisions! To put it mildly, space is not exactly an empty medium (despite what the name might suggest). In truth, there are a lot of things out there on the “stellar highway” that can cause a fatal crash.
For instance, within interstellar space, there are clouds of dust particles and even stray atoms of gas that are the result of stellar formations and other processes. Any spacecraft traveling at 20% the speed of light (0.2 c) could easily be damaged or destroyed if it suffered a collision with even the tiniest of this particulate matter.
The research team was led by Dr. Chi Thiem Hoang, a postdoctoral fellow at Canadian Institute for Theoretical Astrophysics (CITA) at the University of Toronto. As Dr. Hoang told Universe Today via email:
“To evaluate the risks, we calculated the energy that each interstellar atom or dust grain transfers to the ship along the path of the projectile in the ship. This acquired energy rapidly heats a spot on the ship surface to high temperature, resulting in damage by reducing the material strength, melting or evaporation.”
In short, the danger of a collision comes not from the physical impact, but from the energy that is generated due to the fact that the spaceship is traveling so fast. However, what they found was that while collisions with tiny dust grains are very likely, collisions with heavier atoms that can do the most damage would be more rare.
Nevertheless, the damage from so many tiny collisions will certainly add up over time. And it would only take one collision with a larger particle to end the mission. As Dr. Hoang explained:
“We found that the ship would be damaged by collision with heavy atoms and dust grains in the interstellar medium. Heavy atoms, mostly iron can damage the surface to a depth of 0.1mm. More importantly, the surface of the ship is eroded gradually by dust grains, to a depth of about 1mm. The ship may be completely destroyed if encountering a very big dust grain larger than 15micron, although it is extremely rare.”
In terms of damage, what they determined was that each iron atom can produce a damage track of 5 nanometer across, whereas a typical dust silicate grain measuring just 0.1. micron across (and containing about one billion iron atoms) could produce a large crater on the ship’s surface.
Over time, the cumulative effect of this damage would pose a major risk for the ship’s survival. As a result, Dr. Hoang and his team recommended that some shielding would need to be mounted on the ship, and that it wouldn’t hurt to “clear the road” a little as well.
“We recommended to protect the ship by putting a shield of about 1 mm thickness made of strong, high melting temperature material like graphite.” he said. “We also suggested to destroy interstellar dust by using part of energy from laser sources.”
Starshot is the latest in a long line of directed energy concepts that owe their existence to Professor Phillip Lubin. A professor from the University of California, Santa Barbara (UCSB), Lubin is also the mind behind the Directed Energy Propulsion for Interstellar Exploraiton (DEEP-IN) project and the Directed Energy Interstellar Study.
These projects, which are being funded by NASA, seek to harness the technology behind directed-energy propulsion to rapidly send missions to Mars and other locations within the Solar System in the future. Long-term applications include interstellar missions, similar to Starshot.
Other interesting projects overseen by Lubin and the UCSB lab include the Directed Energy System for Targeting of Asteroids and exploRation (DE-STAR). This system calls for the use of lasers to deflect asteroids, comets, and other near-Earth objects (NEO) that pose a credible risk of impact.
In all cases, directed-energy technology is being proposed as the solution to the problems posed by space travel. In the case of Starshot, these include (but are not limited to) inefficiency, mass, and/or the limited speeds of conventional rockets and ion engines.
As Professor Lubin told Universe Today via email, he and his colleagues are in general agreement with the research team and their findings:
“The recent paper by Hoang et al revisits the section (7) in our paper “A Roadmap to Interstellar Flight” that discusses our calculation for the effects of the ISM on the wafer scale spacecraft. Their general conclusion on the effects of the gas and dust collisions were essentially the same as ours, namely that it is an issue, but not a fatal one, if one uses the spacecraft geometry we recommend in our paper, namely orient the spacecraft edge on (like a Frisbee in flight) and then use an edge coating (we use [Beryllium], they use graphite).”
“As for the sail interactions with the ISM we recommend either rotating the sail so it is edge on (lower cross section) or ejecting the sail after the initial few minutes of acceleration as it is no longer needed for acceleration. However. as we desire to use the sail as a reflector for the laser communications we prefer to keep it, though a secondary reflector could be deployed later in the mission if necessary. These detailed questions will be part of the evolving design phase.”
Indeed, there are many safety hazards that have to be accounted for before any mission to interstellar space could be mounted. But as this recent study has shown – with which Professor Lubin agrees – they are not insurmountable, and a mission to Alpha Centauri (or, fingers crossed, Proxima Centauri!) could be performed if the proper precautions are taken.
Who knew the future of space travel would be every bit as cool as we’ve been led to believe – complete with lasers and shielding?
And be sure to enjoy this video from NASA 360, addressing directed-energy propulsion:
Further Reading: arXiv
Setting foot on a distant planet… we’ve all dreamed about it at one time or another. And it has been a staple of science fiction for almost a century. Engage the warp dive, spool up the FLT, open a wormhole, or jump into the cryochamber. Next stop, Alpha Centauri (or some other star)! But when it comes to turning science fiction into science fact, there are certain unfortunate realities we have to contend with. For starters, none of the technology for faster-than-light travel exists!
Second, sending crewed mission to even the nearest planets is a very expensive and time consuming endeavor. But thanks to ongoing developments in the fields of miniaturization, electronics and direct-energy, it might be possible to send tiny spacecraft to distant stars in a single lifetime, which could carry something of humanity along with them. Such is the hope of Professor Philip Lubin and Travis Bradshears, the founders of “Voices of Humanity“.
For people familiar with directed-energy concepts, the name Philip Lubin should definitely ring a bell. A professor from the University of California, Santa Barbara (UCSB), he is also the mind behind the NASA-funded Directed Energy Propulsion for Interstellar Exploraiton (DEEP-IN) project, and the Directed Energy Interstellar Study. These projects seek to use laser arrays and large sails to achieve relativistic flight for the sake of making interstellar missions a reality.
Looking beyond propulsion and into the realm of public participation in space exploration, Prof. Lubin and Bradshears (an engineering and physics student from the University of California, Berkeley) came together to launch Voices of Humanity (VoH) in 2015. Inspired by their work with NASA, this Kickstarter campaign aims to create the world’s first “Space Time Capsule”.
Intrinsic to this is the creation of a Humanity Chip, a custom semiconductor memory device that can be attached to the small, wafer-scale spacecraft that are part of DEEP-IN and other directed-energy concepts. This chip will contain volumes of data, including tweets, media files, and even the digital DNA records of all those who want to take part in the mission. As Professor Lubin told Universe Today in a phone interview:
“We wanted to put on board some part of humanity. We couldn’t shrink ray people down, so Travis and I brainstormed and thought that the next best thing would be to allow people to become digital astronauts. We wanted to pave the way for interstellar missions where we could send the essence of humanity to the stars – “Emissaries of the Earth”, if you will. We wanted to pave the way for that.”
This digital archive would be similar to the Golden Record that was placed on the Voyager probes, but would be much more sophisticated. Taking advantage of all the advances made in computing, electronics and data storage in recent decades, it would contain many millions of times the data, but comprise a tiny fraction of the volume.
In fact, as Lupin explained, the state of technology today allows us to create a digital archive that would be about the same size a fingernail, and which would require no more than a single gram of mass to be allocated on a silicon wafer-ship. And while such a device is not the same as sending astronauts on interstellar voyages to explore other planets, it does allow humanity to send something of itself.
“We now have the technology to put a message from everyone on Earth onto a small piece of a tiny spacecraft,” said Lupin. “We want to begin today, and not just for the future, by putting information onto anything that is launched from Earth. We are the point technologically, at this moment, that we could put a small portion of humanity on this spacecraft.”
In essence, human beings would be able to create the interstellar equivalent of a “Baby on Board” sticker, except for humanity instead. This sticker would be no larger than a postage stamp, and could be mounted on every craft to leave Earth in the near future. In essence, all missions departing from Earth could have “Humanity on Board”.
The plan is to launch their first chip – Humanity Chip 1.0 – into Low Earth Orbit (LEO) in 2017. This will be followed by the creation of Humanity Chip 2.0, which take advantage of the developments that will have occurred by next year. Eventually, they hope that Humanity Chips will be a part of missions that increase in distance from Earth, eventually culminating in a mission to interstellar space.
While there are no deep-space missions ready to go just yet, several concepts are on the table for interplanetary missions that will rely on wafer-scale spacecraft (like NASA’s DEEP-IN concept). If their Kickstarter campaign succeeds in raising the $30,000 necessary to create a Humanity Chip, Prof. Lubin and Bradshears also hope to create a “Black Hole Chip”, where participants will be able to record their “less than happy” thoughts as part of the data, which will then be sent off into space forever.
They also have a stretch goal in mind, known as the “Beam Me Up” objective. In the event that their campaign is able to raise $100,000, they will use the funds to create a ground-based laser array that will beam a package of encoded data towards a target destination in space.
As of the penning of this article, Prof. Lubin and Bradshears have raised a total of $5,656 towards their goal of $30,000. The campaign kicked off earlier this month and will remain open for another 22 days. So if you’re interested in contributing to Humanity Chip 1.0, or becoming an “Emissary of the Earth”, there’s still plenty of time.
In addition to his work with NASA, Prof. Lubin is also responsible for the UCSB’s Directed Energy System for Targeting of Asteroids and ExploRation (DE-STAR) project, a proposed system that would use directed energy (i.e. big lasers!) to deflect asteroids, comets, and other near-Earth objects (NEOs) that could pose a risk to planet Earth.
And, in a recent article titled “The Search for Directed Intelligence“- which appeared in the March 2016 issue of REACH – Reviews in Human Space Exploration – Lupin indicated that advances in directed-energy applications might also help in the search for extra-terrestrial intelligence. Essentially, by looking for for sources of directed energy systems, he claims, we might be able to find our way to other civilizations.
It is an exciting age, where advances in telecommunications and electronics are allowing us to overcome the vast distances involved in space travel. In the future, astronauts may rely on robotic explorers and fast-as-light communications to explore distant worlds (a process known as telexploration). And with a digital archive on board, we will be able to send personal greetings to any life that may already exist there.
For those who would say “sharing personal information with extra-terrestrials is a bad idea”, I would remind them that they (probably) don’t have access to Twitter or our financial records. All the same, it might be wise not to include your Social Security (or Social Insurance) number in the recordings, or any other personal data you wouldn’t share with strangers!
And who knows? Someday, we may start colonizing other planets by sending our DNA there direct. The truth is always stranger than fiction, after all!
And be sure to check out this video produced by Voices for Humanity:
Further Reading: Voices of Humanity
Finding examples of intelligent life other than our own in the Universe is hard work. Between spending decades listening to space for signs of radio traffic – which is what the good people at the SETI Institute have been doing – and waiting for the day when it is possible to send spacecraft to neighboring star systems, there simply haven’t been a lot of options for finding extra-terrestrials.
But in recent years, efforts have begun to simplify the search for intelligent life. Thanks to the efforts of groups like the Breakthrough Foundation, it may be possible in the coming years to send “nanoscraft” on interstellar voyages using laser-driven propulsion. But just as significant is the fact that developments like these may also make it easier for us to detect extra-terrestrials that are trying to find us.
Not long ago, Breakthrough Initiatives made headlines when they announced that luminaries like Stephen Hawking and Mark Zuckerberg were backing their plan to send a tiny spacecraft to Alpha Centauri. Known as Breakthrough Starshot, this plan involved a refrigerator-sized magnet being towed by a laser sail, which would be pushed by a ground-based laser array to speeds fast enough to reach Alpha Centauri in about 20 years.
In addition to offering a possible interstellar space mission that could reach another star in our lifetime, projects like this have the added benefit of letting us broadcast our presence to the rest of the Universe. Such is the argument put forward by Philip Lubin, a professor at the University of California, Santa Barbara, and the brains behind Starshot.
In a paper titled “The Search for Directed Intelligence” – which appeared recently in arXiv and will be published soon in REACH – Reviews in Human Space Exploration – Lubin explains how systems that are becoming technologically feasible on Earth could allow us to search for similar technology being used elsewhere. In this case, by alien civilizations. As Lubin shared with Universe Today via email:
“In our SETI paper we examine the implications of a civilization having directed energy systems like we are proposing for both our NASA and Starshot programs. In this sense the NASA (DE-STAR) and Starshot arrays represent what other civilizations may possess. In another way, the receive mode (Phased Array Telescope) may be useful to search and study nearby exoplanets.”
DE-STAR, or the Directed Energy System for Targeting of Asteroids and exploRation, is another project being developed by scientists at UCSB. This proposed system will use lasers to target and deflect asteroids, comets, and other Near-Earth Objects (NEOs). Along with the Directed Energy Propulsion for Interstellar Exploration (DEEP-IN), a NASA-backed UCSB project that is based on Lubin’s directed-energy concept, they represent some of the most ambitious directed-energy concepts currently being pursued.
Using these as a template, Lubin believes that other species in the Universe could be using this same kind of directed energy (DE) systems for the same purposes – i.e. propulsion, planetary defense, scanning, power beaming, and communications. And by using a rather modest search strategy, he and colleagues propose observing nearby star and planetary systems to see if there are any signs of civilizations that possess this technology.
This could take the form of “spill-over”, where surveys are able to detect errant flashes of energy. Or they could be from an actual beacon, assuming the extra-terrestrials us DE to communicate. As is stated in the paper authored by Lubin and his colleagues:
“There are a number of reasons a civilization would use directed energy systems of the type discussed here. If other civilizations have an environment like we do they might use DE system for applications such as propulsion, planetary defense against “debris” such as asteroids and comets, illumination or scanning systems to survey their local environment, power beaming across large distances among many others. Surveys that are sensitive to these “utilitarian” applications are a natural byproduct of the “spill over” of these uses, though a systematic beacon would be much easier to detect.”
According to Lubin, this represents a major departure from what projects like SETI have been doing during the last few decades. These efforts, which can be classified as “passive” were understandable in the past, owing to our limited means and the challenges in sending out messages ourselves. For one, the distances involved in interstellar communication are incredibly vast.
Even using DE, which moves at the speed of light, it would still take a message over 4 years to reach the nearest star, 1000 years to reach the Kepler planets, and 2 million years to the nearest galaxy (Andromeda). So aside from the nearest stars, these time scales are far beyond a human lifetime; and by the time the message arrived, far better means of communication would have evolved.
Second, there is also the issue of the targets being in motion over the vast timescales involved. All stars have a transverse velocity relative to our line of sight, which means that any star system or planet targeted with a burst of laser communication would have moved by the time the beam arrived. So by adopting a pro-active approach, which involves looking for specific kinds of behavior, we could bolster our efforts to find intelligent life on distant exoplanets.
But of course, there are still many challenges that need to be overcome, not the least of which are technical. But more than that, there is also the fact that what we are looking for may not exist. As Lubin and his colleagues state in one section of the paper: “What is an assumption, of course, is that electromagnetic communications has any relevance on times scales that are millions of years and in particular that electromagnetic communications (which includes beacons) should have anything to do with wavelengths near human vision.”
In other words, assuming that aliens are using technology similar to our own is potentially anthropocentric. However, when it comes to space exploration and finding other intelligent species, we have to work with what we have and what we know. And as it stands, humanity is the only example of a space-faring civilization known to us. As such, we can hardly be faulted for projecting ourselves out there.
Here’s hoping ET is out there, and relies on energy beaming to get things done. And, fingers crossed, here’s hoping they aren’t too shy about being noticed!
Further Reading: arXiv
The uncanny — but unrelated — combination of today’s close flyby of Asteroid 2012 DA14 and the meteor that created an airburst event over Russia has many wondering how we could deal with future potential threats to Earth from space. A group of researchers are hoping to aim a laser-blasting vaporizer in its direction and blow it away.
Dubbed DE-STAR, or Directed Energy Solar Targeting of Asteroids and exploRation, the theoretical orbital system is designed to convert the sun’s energy into laser blasts that would annihilate any cosmic intruders bearing down on Earth.
Although the system sounds like a plot from a science fiction movie, the researchers — led by scientists at two California universities — maintain that it is built on sound principles.
“This system is not some far-out idea from Star Trek,” stated Gary Hughes, a researcher and professor from California Polytechnic State University, San Luis Obispo, in a press release.
“All the components of this system pretty much exist today. Maybe not quite at the scale that we’d need – scaling up would be the challenge – but the basic elements are all there and ready to go. We just need to put them into a larger system to be effective, and once the system is there, it can do so many things.”
Construction details were not clear in a press release advertising DE-STAR, but the researchers describe astonishing results from even a modest-sized version of the system.
DE-STAR was modeled at several different sizes. At 328 feet (100 meters) in diameter, which is double the International Space Station’s size, it could “start nudging comets or asteroids out of their orbits,” Hughes stated.
A 6.2 mile (10-kilometer) DE-STAR version could send 1.4 megatons of energy daily to the marauding asteroid, providing enough juice every year to kill a space rock as big as 1,640 feet (500 meters) across. (That’s more than 10 times the size of 2012 DA14, which came within 17,200 miles of Earth Feb. 15.)
“Our proposal assumes a combination of baseline technology –– where we are today –– and where we almost certainly will be in the future, without asking for any miracles,” added Philip Lubin, who is with the University of California, Santa Barbara.
Besides asteroid annihilation, DE-STAR could give a fuel boost to long-distance space travellers.
A proposed DE-STAR 6 (size not disclosed) is advertised as able to push “a 10-ton spacecraft at near the speed of light, allowing interstellar exploration to become a reality without waiting for science fiction technology such as ‘warp drive’ to come along.”
The press release did not reveal a budget for any version of the DE-STAR, how it would be constructed, or how quickly the system could begin fencing with asteroids.
Researchers emphasized, however, that system proposals such as theirs must be taken seriously to ward off incoming space rocks.
“We have to come to grips with discussing these issues in a logical and rational way,” stated Lubin.
“We need to be proactive rather than reactive in dealing with threats. Duck and cover is not an option. We can actually do something about it and it’s credible to do something. So let’s begin along this path. Let’s start small and work our way up. There is no need to break the bank to start.”
Source: UCSB