We're closing in on the launch of the Cosmos 1 solar sail, the first free-flying spacecraft to be powered by the momentum of solar photons. Yes, there have been deployment experiments before this, such as the Russian Znamya missions and the Japanese deployment of a thin film just last summer. But Cosmos 1 will be a functioning spacecraft capable of returning data, and its launch thus marks an important first in sail development. The launch window opens on June 21. The spacecraft is to be launched into a near polar and circular 800 kilometer orbit, with sail deployment four days later. Cosmos 1 has been moved from the test facility in Moscow to Severomorsk; the plan calls for it to be launched by a converted Russian ICBM from a submerged submarine. If successful, the mission will be a landmark not only for sail propulsion but also for commercial space development. The vehicle was funded by Cosmos Studios, with donations from members of the Planetary Society, whose latest update on the...

Robert Forward's early work on the beamed-energy lightsail, exemplified by the 1984 paper "Round-trip Interstellar Travel Using Laser-Pushed Lightsails," came to grips with the central challenges of interstellar travel. As described in a recent paper on beamed energy requirements for laser sails, these are: How to reach a nearby star within a human lifetime? How to achieve this with known physics? How to hold down the cost, which also means minimizing the energy requirements? How to return the crew to Earth at the end of their explorations? Forward's methods involved huge laser installations near the Sun, lenses fully 1000-kilometers in diameter in the outer Solar System, and a vast sail constructed in three parts so it could be separated (staged), with the outer ring projecting light back on the inner two for deceleration at destination, using the still powerful laser beam from the Sol system. The method is complicated, ingenious and extraordinarily creative. But can we improve on...

Centauri Dreams first ran across Jordin Kare's remarkable SailBeam concept in a report called "High-Acceleration Micro-Scale Laser Sails for Interstellar Propulsion" that the astrophysicist prepared for NASA's Institute for Advanced Concepts (NIAC). The idea seemed outrageously simple: if you accelerate vast numbers of tiny sails rather than one enormous one, you can bring the same amount of mass to high speeds with a less complex optical system. Using dielectric rather than metal sails, you can accelerate the sails much closer to their power source. The stream of microsails then becomes a source of propulsion as it is vaporized into plasma behind a departing starship. Dana Andrews, who has worked with Kare on magsail concepts, notes that a SailBeam Boosted Magsail (SBBM) solves a key problem of particle beam propulsion. A neutral particle beam will disperse as it travels, but a stream of low-mass microsails is not limited by such diffraction. Andrews' MagOrion concept explored some...

In a paper called "Interstellar Propulsion Opportunities Using Near-Term Technologies," Dana G. Andrews (Andrews Space, Seattle) sees two criteria for an interstellar mission. First, it must return results within the lifetime of its principal investigator or the average colonist. Second, it must find cost-effective ways to generate energy and to convert raw energy into directed momentum. These are steep requirements -- we're talking 15 to 20 percent of the speed of light, or 45,000 to 60,000 kilometers per second. Centauri Dreams questions the first criterion, but the need for efficient and effective propulsion is true no matter how fast a mission we manage to design. Robert Forward's massive Fresnel lenses (1000 kilometers in diameter 15 AU from the laser source) are one of those 'small problems in engineering' that the irrepressible Forward managed to concoct while not violating known physics. And Andrews points to a lightsail alternative -- building solar-pumped or...

Beamed propulsion is the classic solution to the mass ratio problem in interstellar flight. Rather than pushing more and more fuel to get your payload to another star system, you leave the fuel behind. Robert Forward's vast lightsail proposals come immediately to mind, but in 2001 physicist Geoffrey Landis proposed propulsion by particle beam, with energy delivered from the Solar System to the departing spacecraft. The notion is this: a charged particle beam is accelerated and focused, then neutralized in charge to prevent the beam from expanding as it travels due to electrostatic repulsion. When the particles reach their target, they are re-ionized and reflected by a magnetic sail, which Landis originally conceived as 'a large superconducing loop with a diameter of many tens of kilometers.' The particle-beam idea seems to solve two problems with lightsails: First, a light beam provides a relatively inefficient energy source, demanding huge power facilities and thus driving up the...

The Planetary Society offers an update on its Cosmos 1 solar sail with the announcement that the spacecraft launch date has slipped to April. Planetary Society executive director Louis Friedman said all flight components had been tested and a full-mission sequence simulated with the spacecraft's on-board computer. The sails are not yet attached to the spacecraft, but will be folded for attachment within the next two weeks. Cosmos 1 will then undergo vacuum chamber testing to check for leaks in its compressed air and fuel lines before being shipped to the launch area. Launch will be aboard a Volna rocket from a Delta III Russian submarine in the Barents Sea. "There is no way to simulate or adequately test how a sail, which is 30 meters long and 5-millionths of a meter thick, will behave under weightless conditions in a vacuum," writes Friedman. "It could oscillate, bounce around and even rip apart. Or it could spread wide and sail effortlessly on beams of light as we hope it will. Our...

If we're looking for an operational solar sail mission that is within our current capabilities -- as Colin McInnes discusses in the quote from his book in yesterday's entry -- GEOSTORM seems just the ticket, and indeed, McInnes has contributed significantly to its design and orbital dynamics. The mission was first conceived at Goddard Space Flight Center and proposed to the National Oceanic and Atmospheric Administration (NOAA) in the 1990s. NOAA requested a mission concept study from the Jet Propulsion Laboratory in 1996. GEOSTORM is conceived as a warning system for geomagnetic storms, which are the result of violent events that release plasma from the solar corona. Predicting them is important because they can affect satellite communications and damage geostationary spacecraft, as well as wreaking havoc with power grids on Earth. But GEOSTORM is also a mission that could advance the state of the art in solar sails as we look toward future deep space missions, including probes to...

"In order to advance solar sailing, proponents need to step back from their enthusiasm which can give the mistaken impression that it is an elegant idea which should be funded for the sake of aesthetics. A cold look at the strengths and weaknesses of the technology is required in order to build a convincing case for support. In particular, it is the weaknesses of solar sailing, either real of perceived, which need to be addressed. While the obvious advantage of potentially unlimited velocity change is perhaps the greatest benefit, it is useless if the first operational solar sails fail to deploy. Historical problems with the deployment of even modest space structures can unfortunately taint solar sailing by association. Similarly, competition from solar-electric propulsion is still a threat, although the new institutional approach to advanced technologies provides a welcome opportunity for exploitation. Given these factors, it seems that what is required is a small, low-cost and...

New Scientist is covering Gregory and James Benford's intriguing sail concept that would get a spacecraft up to 60 kilometers per second. That's faster than any spacecraft we've ever launched; by comparison, the fastest vehicle out there is Voyager 1, now pushing toward the heliopause at some 17.5 kilometers per second. The brothers Benford (Gregory from the University of California -- Irvine and James of Microwave Sciences in Lafayette, CA), talk about beamed microwaves driving a sail design with a difference. At play here is an effect James Benford discovered when testing a thin, carbon-mesh sail with beamed microwaves. The forces exerted on the sail turned out to be stronger than expected, because the heat from the microwave beam was causing outgassing from material in the sail itself. It was the push from these unexpected gas molecules that gave the sail the extra push. You can read the New Scientist story here. I haven't talked to James Benford since 2003, but even then he was...

Interstellar propulsion studies were upstaged in 2004 as we followed planetary exploration: the progress of the Spirit and Opportunity Mars rovers, the Cassini Saturn orbiter and the upcoming Huygens descent onto Titan. But the year was not without significant interstellar news, even though it received little media attention. In separate tests in Ohio and Virginia, two NASA contractors successfully tested solar sail deployments on sails of their own design. In July, L'Garde (Tustin CA) deployed a solar sail nearly 33 feet in length along one side; a separate design created by Able Engineering of Goleta was tested in April and May. The engineering and analysis that went into these tests will help us get sails into space for testing even as we await the launch of the private Cosmos 1 sail sponsored by the Planetary Society. Image: A four-quadrant solar sail system sits fully deployed in a 100-foot-diameter vacuum chamber at NASA's Glenn Research Center Plum Brook Station in Sandusky,...

The Planetary Society has announced that its Cosmos 1 solar sail is to be launched on March 1, 2005. A letter to members from executive director Louis Friedman, who worked on NASA sail designs for an aborted Halley's comet mission in the 1970s, called Cosmos 1 'the world's first solar sail spacecraft.' And indeed it is, if by 'spacecraft' we mean 'free-flying vehicle.' The first Russian Znamya experiments with sail deployment are over a decade old, and involved a 20-meter spinning sail-mirror. Although Znamya was intended to demonstrate the practicality of beaming solar energy to polar and subarctic settlements, the design pointed to a larger concept. When I talked to him last year at JPL, NASA sail expert 'Hoppy' Price showed me a photograph of the deployed sail-mirror, which had problems. "...there are these wrinkles in the sail, so it didn't really work quite the way it was supposed to work," Price said. "And it was a lot heavier than what we'd like to build. But the more we study...

The Planetary Society has struck two agreements with US government agencies to track its Cosmos 1 solar sail. Although ground stations near Moscow will provide the bulk of the tracking, the National Oceanic and Atmospheric Administration (NOAA) will also monitor the mission from its National Environmental Satellite Data Information Service site in Alaska. The US Air Force, meanwhile, will provide images of the deployed sail from the Air Force Maui Optical and Supercomputing site at Haleakala, Hawaii. Other tracking will be provided by the University of California's Berkeley Space Science Laboratory ground station and a ground station in the Czech Republic. Funded by The Planetary Society and Cosmos Studios, the spacecraft was built in Russia by NPO Lavochkin and the Space Research Institute. Planetary Society executive director Louis Friedman has announced that all electronic systems aboard the spacecraft have been flight-qualified and the components have been shipped to the NPO...

Getting a spacecraft to Mars and back in 90 days is one result of developing magnetized-beam plasma propulsion. Mag-beam is the idea of Robert Winglee, whose earlier work on mini-magnetospheric plasma propulsion (M2P2) used the solar wind to push against a plasma bubble created around a spacecraft. Instead of the solar wind, mag-beam uses a plasma beam sent from a space-based station. Its magnetized ions would push against a magnetic sail at speeds that could vary with the size of the beam. "Winglee estimates that a control nozzle 32 meters wide would generate a plasma beam capable of propelling a spacecraft at 11.7 kilometers per second. That translates to more than 26,000 miles an hour or more than 625,000 miles a day," according to this press release from the University of Washington, where Winglee is a space sciences professor. Image: In this artist's conception, a plasma station (lower left) applies a magnetized beam of ionized plasma to a spacecraft bound for Jupiter. Credit:...