Because I get irritable when I don't get my walking in every day, I made sure when I arrived in Palo Alto to cram as much as I could into the day before Breakthrough Discuss began. That meant heading out from the hotel just after noon and putting in about five miles. Palo Alto is a very walkable place and I found myself ambling up and down shady streets past gardens bright with spring flowers. We had superb weather for the entire conference, but naturally when things got going, both days were crammed with talks and long walks were out of the question. But the day before, as I walked, I pondered the schedule of the conference, wondering how a mission to Alpha Centauri fit into the overall plan. In addition to the $100 million going toward Breakthrough Starshot, Breakthrough Initiatives has also put up $100 million for its SETI project, which has already begun operations at Green Bank (West Virginia) and is slated to operate at the Parkes dish in Australia as well, giving SETI the...

Yesterday's announcement of Breakthrough Starshot brought an email from exoplanet hunter Greg Laughlin (UC-Santa Cruz), whose work has been an inspiration to me since the early days of Centauri Dreams. One of Greg's new projects, working with Anthony Aguirre (Foundational Questions Institute) and several other colleagues, is a website called Metaculus, which bills itself as "a community dedicated to generating accurate predictions about future real-world events by aggregating the collective wisdom, insight, and intelligence of its participants." In other words, this is a kind of prediction market space for science and tech issues. Breakthrough Starshot fits the bill here exactly, because Metaculus is all about the probability of future events, some of which can be predicted to a high degree, while others are purely a matter of calculated odds. The site is open to all and contains the basic information about its methods, and any logged in user can propose a question for consideration....

Here on Centauri Dreams we often discuss interstellar flight in a long-term context. Will humans ever travel to another star? I've stated my view that if this happens, it will probably take several hundred years before we develop the necessary energy resources to make such a mission fit within the constraints of the world's economy. This, of course, assumes the necessary technological development along the way — not only in propulsion but in closed-loop life support — to make such a mission scientifically plausible. I get a lot of pushback on that because nobody wants to wait that long. But overall, I'm an optimist. I think it will happen. Let's attack the question from another direction, though, and leave human passengers for a later date, as Yuri Milner's Breakthrough Initiatives, aided by Stephen Hawking, is doing today in a New York news conference. What if we talk about unmanned missions? What if, in fact, the question is: How soon can we put a scientific payload...

We haven't yet found Planet Nine, but the evidence for its existence is solid enough that we can start thinking about its possibilities as a mission target. That work falls in this essay to Adam Crowl, a Centauri Dreams regular whose comments on articles here began not long after I started the site. An active member of the Project Icarus attempt to re-design the 1970s Project Daedalus starship, Adam is also the author of Crowlspace, where his insights are a frequently consulted resource. Today he harkens back to a 1960s science fiction story that has given him notions about a way not only to reach Planet Nine but to establish orbit around it. by Adam Crowl Fritz Leiber is better known for his fantasy and SF-fantasy, but he could write hard-SF too. A fine example is his 1962 story, "The Snowbank Orbit", the title of which alludes to World War II tales of pilots surviving bailouts without parachutes by plunging into snow-drifts. Five spacecraft, racing towards Uranus at 100 miles per...

Like the Marie Celeste, the Leonora Christine is a storied vessel, at least among science fiction readers. In his 1967 story "To Outlive Eternity," expanded into the novel Tau Zero in 1970, Poul Anderson described the starship Leonora Christine's stunning journey as, unable to shut down its runaway engines, it moved ever closer to the speed of light. Just how a real Leonora Christine might cope with the stresses of a ramjet's flight into the interstellar deep is the subject of Al Jackson's latest, which draws on memories not only of Robert Bussard, who invented the interstellar ramscoop concept, but a young scientist named John Ford Fishback. by A. A. Jackson Project Pluto - a program to develop nuclear-powered ramjet engines - must have been on Robert Bussard's mind one morning at breakfast at Los Alamos. Bussard was a project scientist-engineer on the nuclear thermal rocket program Rover -- Bussard and his coauthor DeLauer have the two definitive monographs on nuclear propulsion...

Our second report from the recent Tennessee Valley Interstellar Workshop is the work of Cassidy Cobbs and Michel Lamontagne, with an emphasis on the worldship track. Cassidy has an MS from Vanderbilt, where she studied ecology and evolution. She currently works at Memorial Sloan Kettering Cancer Center, doing traditional and next-generation gene and genome sequencing. Her interest in space travel/engineering was enhanced by attending Advanced Space Academy in Huntsville at age 14. Michel Lamontagne is a French-Canadian mechanical engineer, practicing in the fields of heat transfer and ventilation, with a passion for space. An active member of Icarus Interstellar, he tells me he has "been designing spaceships since he was 12 years old, and waiting for reality to catch up!" Photos throughout are from New York photojournalist Joey O'Loughlin, and are used with permission. By Cassidy Cobbs and Michel Lamontagne This year's Tennessee Valley Interstellar Workshop (TVIW-2016) was held in...

I always feel that my day starts right when a story involving the Voyagers crosses my desk. The scope, the sheer audacity of these missions in their day cheers me up, and the fact that they are still communicating with us is a continual cause for celebration. With Voyager 1 now moving beyond the heliosphere, we've got an interstellar craft on our hands, one that's telling us a good deal about the perturbed regions through which it moves. Every day that the Voyagers stay alive is a triumph for an inquisitive and exploring species, and one day we'll be launching their successor, targeting the local interstellar medium with instruments designed for the task. Image: This artist's concept shows NASA's Voyager spacecraft against a backdrop of stars. Credit: NASA/JPL-Caltech. The heliosphere is that 'bubble' blown by the particles of the Sun's solar wind in surrounding interstellar space. As such, it's a moving and malleable thing, flexing, flowing, contracting here, expanding there...

As we close in on perihelion at Comet 67P/Churyumov-Gerasimenko, the Dawn spacecraft continues its operations at Ceres. The contrast between Dawn's arrival at Ceres in March and New Horizons' flyby of Pluto/Charon could not have been more striking. With Dawn's gentle ion push, we watched Ceres gradually grow in the skies ahead, and then settle into focus as the spacecraft began orbital operations. New Horizons was a thrilling, high-velocity fling, with a sudden transition to a backlit Pluto as we settled in to wait for months of data return. Dawn is now heading for its third science orbit, gradually descending through 1900 kilometers toward an eventual 1500 kilometer altitude above the surface -- this is fully three times closer to Ceres than the previous orbit. Again, the gentle nature of ion propulsion is evident, for the spacecraft will reach the new orbit in mid-August, when data operations and imagery again flow. Bear in mind as you think about Pluto and Ceres that the latter is...

With the fanfare of the New Horizons flyby of Pluto/Charon, we learned that public interest in space can be robust, at least to judge from the number of people I spoke to who had never previously seemed aware of the subject. Here's hoping that interest continues to be piqued -- as it should be -- by the ongoing events at Ceres and on Comet 67P/Churyumov-Gerasimenko. With Ceres we have another exploration of a hitherto unknown surface, while the Rosetta spacecraft is watching surface activity on a comet of the kind we've never seen up close. We've already spent a year at the comet since Rosetta's arrival on August 6 of last year, examining the object's frozen ices and dust as they vaporize with increasing warmth from the Sun. The gas and dust 'atmosphere' thus created, called the coma, can produce the kind of spectacular tails we've long associated with comet observations from Earth. Perihelion occurs on August 13, when the comet reaches a distance of 186 million kilometers from the...

Given that the Philae lander has just come to life after seven months without communicating, it's no wonder that the mood among everyone involved with Rosetta's mission to comet 67P/Churyumov-Gerasimenko is exuberant. On the surface of the comet, conditions have been improving for Philae since March, meaning that with higher temperatures and better illumination, it was hoped that the lander might reactivate. That hope was realized on June 13 when Rosetta picked up 330 data packets from an earlier segment of the lander's mission. Stephan Ulamec (DLR), Philae lander project manager, has positive things to say: "We are still examining the housekeeping information at the Lander Control Centre in the DLR German Aerospace Center's establishment in Cologne, but we can already tell that all lander subsystems are working nominally, with no apparent degradation after more than half a year hiding out on the comet's frozen surface." Image: Processed NAVCAM image of Comet 67P/C-G taken on 5 June...

In a summer already packed with interesting missions, we also have the unusual phenomenon of spacecraft ‘waking up’ after unexpected periods of dormancy. The European Space Agency’s Philae lander, which shut down on November 15, 2014 after operating on comet 67P/Churyumov-Gerasimenko for about sixty hours, came out of its hibernation on June 13. ESA reports more than 300 data packets have been received and are being analyzed. Image: Twitter lit up with news of Philae’s reappearance. Be sure to track @ESA_Rosetta to keep up with the latest. This first contact since November lasted for 85 seconds, and according to reports from ESA, made it apparent that the lander had been retrieving data during the time of communications blackout. This ESA update notes that there are more than 8000 data packets in Philae’s memory that can be accessed (we hope) on the next contact, giving us information about the lander’s most recent activity as the comet and orbiting Rosetta continue toward...

The Planetary Society's Emily Lakdawalla tells us (via Twitter) that she has a history with jigsaw puzzles, one that finally paid off in the image below. You're looking at her work on a partially de-scrambled image from LightSail, fragmentary because the entire image was not downloaded during a Cal Poly (San Luis Obispo) overflight on the afternoon of the 8th. The complete image should be downloaded later today, and perhaps shown at an upcoming press conference with LightSail engineering team leaders scheduled for Wednesday June 10 at 1730 UTC (1330 EDT). At any rate, LightSail's deployed sails are in view. Bill Nye, CEO of The Planetary Society, was on National Public Radio yesterday (audio here) in a brief spot in which he described the unfurling of the solar sail as a 'sail Mary pass,' a longshot required by circumstance as the spacecraft continued to tumble. If the phrase 'sail Mary pass' is inscrutable to you, you may not be familiar with American football, where 'hail Mary...

What a time for space missions, with data returning from far places and a nail-biter close at hand. On the latter, be advised that the LightSail mission team has decided to divide sail deployment into two operations, one of them starting today as the CubeSat's solar panels are released and an imaging session verifies the craft is ready for sail deployment. The actual deployment will then follow on Friday, and is currently scheduled for 1647 UTC (1247 EDT). From Jason Davis: The first indication the sail sequence has started should come from the spacecraft's automated telemetry signals, which include a motor revolution count for the boom system. The next few orbits will be used to check LightSail's health and status, transfer imagery from the cameras to flight computer, and begin sending home to Earth.The last contact of the day comes during a Cal Poly ground pass at 4:16 p.m. EDT (20:16 UTC). By then, the team hopes to at least part of a sail image on the ground. If not, the next...

Not long ago I looked at the future of the Voyager spacecraft and noted a possibility once suggested by Carl Sagan. Give the Voyagers one last 'empty the tank' burn and both could be put on a trajectory that would take them near, if not through, another star's system (see Voyager to a Star). It would be little more than a symbolic act, for even with heroic measures to conserve power, neither Voyager will be able to communicate past the mid-2020s. With a little luck, perhaps 2030. So we would be sending two spacecraft off to a star as a final act, turning them into markers, or monuments, that show humans are capable of producing something that will eventually reach (or come close to) another stellar system. Given their current trajectories, each Voyager passes interestingly close to another star in about 40,000 years, or roughly the amount of time since the extinction of homo neanderthalensis. The mere act of relating objects created by our species and launched in 1977 to time frames...

While we wait for the Dawn spacecraft to come back around the lit side of Ceres as it continues a long period of orbital adjustment, let's check in on two other spacecraft with the potential for a big science return. New Horizons performed a 93-second thruster burn on March 10 that was the farthest burn from Earth of any spacecraft in history. We're now in the approach phase to Pluto/Charon and this was the first maneuver of that phase, designed to slow the spacecraft by a mere 1.14 meters per second. The New Horizons team describes this as 'a tap on the brakes' considering that the probe is moving at 14.5 kilometers per second. As this New Horizons news update informs us, yesterday's burn delayed arrival time at Pluto/Charon by 14 minutes, 30 seconds as the spacecraft's course was adjusted. New Horizons is now 149 million kilometers from Pluto -- in other words, 1 astronomical unit, or AU, meaning the spacecraft is the same distance from its target as the Earth is from the Sun. It...

I find few things more fascinating than remote fixes to distant spacecraft. We've used them surprisingly often, an outstanding case in point being the Galileo mission to Jupiter, launched in 1989. The failure of the craft's high-gain antenna demanded that controllers maximize what they had left, using the low-gain antenna along with data compression and receiver upgrades on Earth to perform outstanding science. Galileo's four-track tape recorder, critical for storing data for later playback, also caused problems that required study and intervention from the ground. But as we saw yesterday, Galileo was hardly the first spacecraft to run into difficulties. The K2 mission, reviving Kepler by using sophisticated computer algorithms and photon pressure from the Sun, is a story in progress, with the discovery of super-Earth HIP 116454 b its first success. Or think all the way back to Mariner 10, launched in 1973 and afflicted with problems including flaking paint that caused its...

The interstellar mission that Dana Andrews describes in his recent paper -- discussed here over the past two posts -- intrigues me because I'm often asked what the first possible interstellar mission might be. Sure, we can launch a flyby Voyager-class probe to Alpha Centauri if we're willing to tolerate seventy-five thousand years in cruise, but what would we accept by way of acceptable cruise times? The lifetime of a human being? Multiple generations? And if we had to launch as soon as possible, what would the mission parameters be? The mission that Andrews conceives grows out of questions like these. I can say upfront that this isn't a mission I would want to fly on. For one thing, it's a generation ship, so entire lives will be spent in cramped quarters, and the prospect of being overtaken by a later, faster ship is always there. But that's not the point. 18th Century voyagers with a yen for the unknown could have waited for the age of steamships, but how could they have...

If our exoplanet hunters eventually discover an Earth-class planet in the habitable zone of its star -- a world, moreover, with interesting biosignatures -- interest in sending a robotic probe and perhaps a human follow-up mission would be intense. In fact, I'm always surprised to get press questions whenever an interesting exoplanet is found, asking what it would take to get there. The interest is gratifying but I always find myself having to describe just how tough a challenge a robotic interstellar mission would be, much less a crewed one. But we should keep thinking along these lines because the odds are that exoplanetary science may well uncover a truly Earth-like world long before we are in any position to make the journey. I would expect public fascination with such a discovery to be strong. Dana Andrews (Andrews Space, now retired) has been pondering these matters and recently forwarded a paper he presented at the International Astronautical Congress meeting in Toronto in...

In mid-June, NASA announced the award of two contracts with Deep Space Industries in conjunction with the agency's plans to work with private industry in the exploration and harvesting of asteroids. One of these contracts caught my eye immediately. It involves small payloads that can ride along to supplement asteroid missions, and it's in the hands of NASA's former Chief Technologist, Mason Peck, a Cornell University aerospace engineer. Peck's work at Cornell's Space Systems Design Studio has led to the development of Sprites, fully functional spacecraft each weighing less than a penny. You can think of a Sprite as a spacecraft on a chip without any constraints from onboard fuel. You can see where this fits in with the current theme of building smaller spacecraft and sending them in swarms to investigate a particular target. You may have already run into KickSat, a citizen science project involving hundreds of proof-of-concept spacecraft in low Earth orbit for assessment of their...

When Carl Sagan and Iosif S. Shklovskii discussed travel to another galaxy in Intelligent Life in the Universe (Holden-Day, 1966), they considered the problem from the standpoint of the technologies then under discussion by theorists like Robert Forward and Robert Bussard. As I mentioned yesterday, the authors found hibernation interesting, drawing on the ideas of the Swedish biologist Carl-Göran Hedén, with whom Sagan was then in contact. But it was time dilation that took center stage in their book, and that required stunning velocities. To reach M31, the Andromeda galaxy, in a human lifetime would require a velocity of 0.99999 c. Behind the relativistic spacecraft on Earth, millions of years would have passed, but the same crew that departed would reach their destination. Here is Sagan discussing the matter. And a brief note: Sagan's practice was to interleave his own material with that of Shklovskii, so that while the names of both authors are on the title page, it's easy...