Testing out new sail applications is part of a European project called RemoveDebris, which focuses on strategies for dealing with the enormous amount of junk that is piling up around the Earth. Run by the Surrey Space Center at the University of Surrey (UK) and the Von Karman Institute of Belgium, the work takes note of the fact that, from flecks of paint to inactive satellites to spent rocket boosters, our planet is orbited by about 7000 tonnes of material. If you want to visualize that amount, it's the equivalent of 583 London buses, according to this SSC news release. You may recall that in the film Gravity, a Space Shuttle is destroyed by space debris. But the issue is hardly confined to Hollywood imaginings. Jason Forshaw is Surrey Space Centre project manager on the RemoveDebris team: "Various orbits around the Earth that are commonly used for satellites and space missions are full of junk, which is a significant danger to our current and future spacecraft. Certain orbits -...

Looking around on the Net for background information about Jordin Kare, who died last week at age 60 (see yesterday's post), I realized how little is available on his SailBeam concept, described yesterday. SailBeam accelerates myriads of micro-sails and turns them into a plasma when they reach a departing starship, giving it the propulsion to reach one-tenth of lightspeed. Think of it as a cross between the 'pellet propulsion' ideas of Cliff Singer and the MagOrion concept explored by Dana Andrews. So I thought this morning to offer you some thoughts about SailBeam and its genesis from the man himself. I interviewed Jordin back in early 2003 in a wide-ranging discussion that took in most aspects of his work. He was an easy interview -- all I had to do was offer the occasional nudge and he would take off. I found him engaging and hugely likeable. What follows is a fraction of the entire interview, the part that focuses primarily on SailBeam and a bit on Kare himself. I've edited it...

Breakthrough Starshot, the ambitious 30-year plan for launching small interstellar craft to a nearby star, depends critically on the sails that will ride a laser beam to 20 percent of lightspeed. In the essay below, James Benford takes a hard look at where we are now in the matter of sail stability, a subject he and brother Gregory have analyzed in their laboratory work. But as Jim points out, there is a great deal we still don't know, emphasizing the need for a dedicated test facility in which deep analysis and experimentation can proceed. The Chairman of the Sail Subcommittee for Breakthrough Starshot, Dr. Benford gives us insight into the magnitude of the challenge, and the possible solutions now being considered. By James Benford Riding on the beam, i.e., stable flight of a sail propelled by beam momentum, is an essential requirement of beam-driven propulsion. It places considerable demand upon the shape of the sail and beam. Some amount of beam jitter, oscillations in the...

No spacecraft has ever flown as close to the Sun as the Parker Solar Probe will. The spacecraft will penetrate the outer solar atmosphere -- the corona -- where its measurements should help us understand the origin and characteristics of the solar wind. To put this in perspective, consider that Mercury is at 0.39 AU. The Helios-B spacecraft, launched in 1976, closed to within 43 million kilometers of the Sun (0.29 AU), the current record for a close pass. The Parker Solar Probe will fly seven times closer, moving within ten solar radii. We need to learn a lot more about this region as we consider various mission concepts for the future. The Parker Solar Probe uses an 11.43 cm carbon-composite shield designed to keep its instrument package at room temperature, or close to it, despite outside temperatures well over 1350° Celsius. The sundiver concept we talked about yesterday -- sometimes called a 'fry-by' -- has the advantage of maximizing the effect of solar photons by unfurling...

We're going to be keeping a close eye on what is now called the Parker Solar Probe as work continues toward a July 2018 launch. This is a mission with serious interstellar implications because it takes us into the realm of so-called 'sundiver' maneuvers in which a solar sail could be brought as close as possible to the Sun (perhaps behind a protective occulter) and then unfurled to get maximum effect. Velocities well beyond Voyager's can grow from this. Throw in the prospect of beamed propulsion and such sails could receive an additional boost. To be sure, the Parker Solar Probe is not a solar sail but an unmanned, instrumented probe designed to explore a region as close as 10 solar radii from the Sun's surface, where temperatures can be expected to reach about 1375° Celsius. But the sundiver implications are there, and we'll gain priceless data about operations in this extreme environment. Why a sundiver? Voyager 1 is exiting the neighborhood of the Solar System at 17.1...

Some years back I had the pleasure of asking Lou Friedman about the solar sail he, Bruce Murray and Carl Sagan championed at the Jet Propulsion Laboratory in the 1970s. NASA had hopes of reaching Halley's Comet with a rendezvous mission in 1986. Halley's closest approach that year would be 0.42 AU, but the comet was on the opposite side of the Sun from the Earth, making ground viewing less than impressive. Although the JPL mission did not fly, the Soviet Vega 1 and Vega 2 conducted flybys and the European Space Agency's Giotto probe, as well as the Japanese Suisei and Sakigake, made up an investigative 'armada.' But the abortive NASA concept has always stuck in my mind because it seemed so far ahead of its time. Friedman acknowledged as much in our short conversation, saying that while the ideas were sound, the solar sail technology wasn't ready for the ambitious uses planned for it. Friedman, of course, would go on to become a founder of The Planetary Society and its long-time...

Deceleration has always been problematic in projected schemes for interstellar travel. A flyby of a star at a substantial percentage of lightspeed yields a fraction of the data that would be obtainable by a probe slowed into orbit in the target system. But how to slow down? In particular, how do you slow down when your method of propulsion is beamed energy? The ideas have flowed over the years, ranging from Philip Norem’s ‘thrustless turning’ -- using interactions between the spacecraft and the interstellar magnetic field -- to Robert Forward’s ‘staged’ sail, in which the sail separates into separate components, with beamed laser light from Earth bouncing off one to the other to slow the payload. Norem’s notion, though, hugely lengthened trip times while taking the spacecraft far beyond the target before turning it back, while staged sails require a pointing accuracy in a laser array that is hard to imagine. Many other options have been advanced, including braking against a stellar...

I like the way Jun Matsumoto approaches his work. A researcher with JAXA (Japan Aerospace Exploration Agency), Matsumoto is deeply involved in the design of the space sail that will pick up where Japan's IKAROS left off. Launched in 2010, the latter was a square sail 14 meters to the side that demonstrated the feasibility of maneuvering a sail on interplanetary trajectories. JAXA has talked ever since about going to Jupiter, but the challenges are formidable, not the least of which is the question of generating enough power to operate over 5 AU from the Sun. Image: A computer rendering shows what JAXA's solar sail may look like as it approaches an asteroid. The probe is at the sail's center. Credit: Japan Aerospace Exploration Agency. But back for a moment to Matsumoto, who has the kind of long-term approach to his work that this site has long championed. I ran into him in an article in the Japan Times that ran last summer (thanks to James Jason Wentworth for the pointer). Matsumoto...

Breakthrough Starshot's four-meter sails are the latest (and best funded) concept in a long series of beamed propulsion ideas. As Jim Benford explains below, the idea of beaming to a sail goes back over fifty years, with numerous papers and the beginnings of laboratory work in the intervening decades. What follows is the first cut at a timeline of this work, one that Jim intends to supplement and re-publish here with full references. Keeping in mind the scope of the timeline as Jim explains it, feel free to suggest any missing references in the comments. Discover Magazine, by the way, has just published a look at the Benfords' work on beamed sails called "Riding on a Beam of Light," now available for subscribers online. by James Benford From recent media pieces following the announcement of Breakthrough: Starshot, I gather that the press is not aware of how much has been done by the propulsion community over the last decades in the areas of photon beam-driven sail system concepts, to...

The Planetary Society's LightSail-A, launched on May 20 of this year, demonstrated sail deployment from a CubeSat despite software problems that plagued the mission. You'll recall that communications were spotty and the upload of a software fix was compromised because of the spacecraft's continued tumbling. After a series of glitches, the craft's sail was deployed on the 7th of June, with LightSail-A entering the atmosphere shortly thereafter, a test flight that did achieve its primary objective, serving as a prototype for the upcoming LightSail-1. Mixing CubeSats with solar sails seems like an excellent idea once we've ironed out the wrinkles in the technology, and as I've speculated before, we may one day see interplanetary missions carried out by small fleets of CubeSats propelled by solar sails. Although the LightSail-A demonstrator mission was in a low orbit, LightSail-1 will deploy its four triangular sails once it reaches an orbital altitude of 800 kilometers. A key reading...

Today we look beyond Pluto/Charon toward possible ways of getting a payload to another star. Centauri Dreams readers are familiar with the pioneering work of Robert Forward in developing concepts for large-scale laser-beamed missions to Alpha Centauri and other destinations. But what if we go smaller, much smaller? Project Dragonfly, in progress at the Initiative for Interstellar Studies, proposes to explore this space, and as Andreas Hein explains below, it was recently examined in a workshop giving student teams a chance to present their ideas. A familiar figure in these pages, Andreas received his master's degree in aerospace engineering from the Technical University of Munich and is now working on a PhD there in the area of space systems engineering, having conducted part of his research at MIT. by Andreas M. Hein The Project Dragonfly Design Competition, organized by the Initiative for Interstellar Studies (i4is) was concluded on the 3rd of July in the rooms of the British...

Last week we looked at DE-STAR (Directed Energy Solar Targeting of Asteroids and Exploration), an ambitious program for developing modular phased arrays of kilowatt class lasers. The work of Philip Lubin (UC-Santa Barbara), DE-STAR is envisioned as a way to scale up a space-based system for asteroid mitigation. And in a new NIAC grant, Lubin will study an off-shoot called Directed Energy Propulsion for Interstellar Exploration (DEEP-IN) as a way of driving tiny 'wafer' probes on interstellar journeys. Reading about these ideas, Jim Benford responded with the comments below. A plasma physicist and president of Microwave Sciences (Lafayette, CA), Dr. Benford's work on microwave beaming to sailcraft has included laboratory experiments at JPL with brother Greg that I've written about in these pages. Here are his thoughts on DE-STAR's beaming methods and the issues they invoke. by James Benford The calculations presented by the DE-STAR group are basically a revisit of the work of Bob...

The last interstellar concept I can recall with a 20-year timeline to reach Alpha Centauri was Robert Forward's 'Starwisp,' an elegant though ultimately flawed idea. Proposed in 1985, Starwisp would take advantage of a high-power microwave beam that would push its 1000-meter fine carbon mesh to high velocities. As evanescent as a spider web, the craft would use wires spaced the same distance apart as the wavelength of the microwaves that drove it, which is how it could be so lightweight and yet maintain rigidity under the microwave beam. Throw in sensors and circuitry built-into the sail itself and you had no need for a separate probe payload -- Starwisp was its own payload. This was conceived as a flyby mission, in which the microwaves would again bathe the craft as it neared its target, providing just enough energy to drive its communications and sensor array to return data to Earth. What a mission: Starwisp would accelerate at 115 g's, its beam pushing it up to 20 percent of...

The main post for today will be online around 1230 EDT (1630 UTC), but first I have to publish this image from LightSail, along with Jason Davis' description. Nice work! "The Planetary Society's LightSail test mission successfully completed its primary objective of deploying a solar sail in low-Earth orbit, mission managers said today [June 9]. During a ground station pass over Cal Poly San Luis Obispo that began at 1:26 p.m. EDT (17:26 UTC), the final pieces of an image showcasing LightSail's deployed solar sails were received on Earth. The image confirms the sails have unfurled, which was the final milestone of a shakedown mission designed to pave the way for a full-fledged solar sail flight in 2016." A second image may include a view of the Earth, according to Davis. What may happen next is a further tensioning, or 'walking out,' of the sail booms, which should further flatten the sail. Davis notes, too, that the 'fish-eye' lens of the camera produces a bit of distortion in the...

After a nerve-wracking week in which contact was repeatedly lost and then regained, The Planetary Society's LightSail has successfully charged its batteries and deployed its solar sail. Deployment began at 1947 UTC (1547 EDT) June 7, just off the coast of Baja California, with telemetry showing climbing motor counts and power levels consistent with ground testing. In a late afternoon update, Jason Davis also noted that the spacecraft's cameras were on (see Deployment! LightSail Boom Motor Whirrs to Life). If you're following this mission closely, you'll want to know about Ted Molczan's page LightSail-A: Estimated Post-Sail Deployment Orbital Elements, with early predictions on orbital decay with the sails extended. Bonnie Link (hflink.com) produced a map showing Monday's LightSail passes over North America that you can see below. Here the white boxes are UTC times. The green arcs are sunlit, the blue in shadow and thus not visible. Further confirmation of sail deployment came in a...

It was a worrisome eight days, but LightSail has broken its silence with an evident reboot and return to operations, sending telemetry to ground stations and taking test images. We now have sail deployment possibly as early as Tuesday morning EDT (15:44 UTC), but according to The Planetary Society's Jason Davis, much will depend on today's intensive checkout. Planetary Society CEO Bill Nye issued this statement on the spacecraft's reawakening: "Our LightSail spacecraft has rebooted itself, just as our engineers predicted. Everyone is delighted. We were ready for three more weeks of anxiety. In this meantime, the team has coded a software patch ready to upload. After we are confident in the data packets regarding our orbit, we will make decisions about uploading the patch and deploying our sails— and we'll make that decision very soon. This has been a rollercoaster for us down here on Earth, all the while our capable little spacecraft has been on orbit going about its business....

The Planetary Society's LightSail won't stay in orbit long once its sail deploys, a victim of inexorable atmospheric drag. But we're all lucky that in un-deployed form -- as a CubeSat -- LightSail can maintain its orbit for about six months. Some of that extended period may be necessary given the problem the spacecraft has encountered: After returning a healthy stream of data packets over its first two days of operations, the solar sail mission has fallen silent. Jason Davis continues his reporting on LightSail, with the latest update on the communications problem now online. We learn that the suspected culprit for LightSail's silence is a simple software glitch. Everything else looked good when communications ceased, with power and temperature readings stable. Davis explains that during normal operations, LightSail transmits a telemetry beacon every 15 seconds. The Linux-based flight software writes data on each transmission to a .csv file, a spreadsheet-like record of ongoing...

One of the joys of science fiction is the ability to enter into conjectured worlds at will, tweaking parameters here and there to see what happens. I remember talking a few years ago to Jay Lake, a fine writer especially of short stories who died far too young in 2014. Jay commented that while it was indeed wonderful to move between imagined worlds as a reader, it was even more wondrous to do so as a writer. I've mostly written non-fiction in my career, but the few times I've done short stories, I've experienced a bit of this 'world-building' sense of possibility. Even so, it's always striking how science and technology keep moving in ways that defy our expectations. Take yesterday's launch of The Planetary Society's crowd-funded LightSail, which went aloft thanks to the efforts of a United Launch Alliance Atlas V from Cape Canaveral. LightSail violates expectations on a number of fronts. For one thing, the crowd-funding thing, which is a consequence of an Internet era that science...

Andreas Hein recently wrote up the Project Dragonfly design competition, which has been running as a Kickstarter project. Leveraging advances in miniaturization and focusing on laser-beamed lightsail technologies, Project Dragonfly aims to study the smallest possible spacecraft. From the Kickstarter announcement: Project Dragonfly builds upon the recent trend of miniaturization of space systems. Just a few decades ago, thousands of people were involved in developing the first satellite Sputnik. Today, a handful of university students are able to build a satellite with the same capability as Sputnik, which is much cheaper and weighs hundreds of times less than the first satellite. We simply think further. What could we do with the technologies in about 20-30 years from now? Would it be possible to build spacecraft that can go to the stars but are as small as today's picosatellites or even smaller? You can read about the competition in Andreas' post Project Dragonfly: Design...

by Andreas Hein Centauri Dreams readers most likely know Andreas Hein as the head of Project Hyperion, an effort for Icarus Interstellar to examine the prospects for manned interstellar flight, but he has also written in these pages about the uploading of consciousness. Now working on his PhD at the Technical University of Munich, Andreas today tells us about a new Kickstarter campaign in support of Project Dragonfly. Developing under the auspices of the Initiative for Interstellar Studies (of which Andreas is deputy director), Dragonfly explores interstellar flight at the small scale, and as he explains below, leverages the advances in computing and miniaturization that designers can use to change the paradigm of deep space missions. Humanity has existed for over 200,000 years. It is only about 200 years since we entered the age of industrialization, and in the last 50 years, we have discovered ways of going to the stars [1]. However, the approaches conceived required spaceships the...