Archives

Sail in View

by Paul Gilster | Jun 10, 2015 | Sail Concepts | 11 Comments

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...

Mission Updates Far and Near

by Paul Gilster | Jun 9, 2015 | Missions | 9 Comments

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...

LightSail Deployment Apparently Successful

by Paul Gilster | Jun 8, 2015 | Sail Concepts | 5 Comments

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...

The View from Outside the Galaxy

by Paul Gilster | Jun 5, 2015 | Deep Sky Astronomy & Telescopes | 17 Comments

The Russian Federal Space Agency (Roscosmos) has recently released a video (viewable here on YouTube) showing how a number of celestial objects might look if they were substantially closer to Earth than they are. The image of the Andromeda galaxy and its trillion stars projected against an apparent Earthscape is below. Unfortunately, this seems to be an astronomical image inserted into a view that purports to show what we would see in visible light. What we would actually see if we were standing in such a location is much different. After all, astronomical images are teased out of lengthy exposures in carefully chosen wavelengths. In reality the Andromeda galaxy is gigantic even when viewed from 2.5 million light years, but I doubt the average person has any idea where it is in the sky. Although considerably wider than the Moon as seen from Earth, M31 is visually faint, a fact that reminds us of the importance of photographs and charged coupled devices (CCDs) in light gathering as we...

Science Fiction: An Updated Solar System

by Paul Gilster | Jun 4, 2015 | Culture and Society | 9 Comments

Having written yesterday about the constellation of missions now returning data from deep space, I found Geoffrey Landis' essay "Spaceflight and Science Fiction" timely. The essay is freely available in the inaugural issue of The Journal of Astrosociology, the publication of the Astrosociology Research Institute (downloadable here). And while it covers some familiar ground -- Jules Verne's moon cannon, Frau im Monde, etc. -- it also highlights Landis' insights into the relationship between the space program and the genre that helped inspire it. My friend Al Jackson has written in various comments here (and in a number of back-channel emails) about Wernher von Braun's ideas and their relation to science fiction. As Landis notes, von Braun was himself a science fiction reader who credited an 1897 novel called Auf Zwei Planeten (Two Planets) by Kurd Lasswitz with inspiring his interest in rocketry. So, by the way, did Walter Hohmann, the German engineer who helped develop the area of...

Mission Data: An Early Summer Harvest

by Paul Gilster | Jun 3, 2015 | Missions | 6 Comments

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...

A Kuiper Belt in the Making

by Paul Gilster | Jun 2, 2015 | Exoplanetary Science | 3 Comments

The Scorpius-Centaurus OB association is a collection of several hundred O and B-class stars some 470 light years from the Sun. Although the stars are not gravitationally bound, they are roughly the same age -- 10 to 20 million years -- their formation triggered by a series of supernovae explosions in large molecular clouds. Now the Gemini Planet Imager on the Gemini South instrument in Chile has uncovered a young planetary system within the association, one with solid similarities to our own Solar System in its infancy. In fact, says lead author Thayne Currie (Subaru Telescope), the ring orbiting the star HD 115600 could be a Solar System clone. “It’s kind of like looking at [our] outer solar system when it was a toddler,” the astronomer adds, noting that the ring is about the same distance from its host star as the Kuiper Belt is from the Sun, receiving about the same amount of light from an F-class star that is about fifty percent more massive than our own G-class Sol. Image: The...

LightSail Reboots: Sail Deployment Soon

by Paul Gilster | Jun 1, 2015 | Sail Concepts | 15 Comments

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....

Transhumanism and Adaptive Radiation

by Paul Gilster | May 29, 2015 | Culture and Society | 36 Comments

Centauri Dreams regular Nick Nielsen here tackles transhumanism, probing its philosophical underpinnings and its practical consequences as civilization spreads outward from the Solar System. In a sense, transhumanism is what humans have always done, the act of transcendence through technology being a continuing theme of our existence. But accelerating technologies demand answers about human freedom in the context of a species that will inevitably bifurcate as it takes to the stars. Think of the 'Cambrian explosion' as a model as we consider what is to come. The author's philosophy often takes him into mathematics (hence a digression on Georg Cantor and set theory), but the prolific Nielsen (Grand Strategy: The View from Oregon and Grand Strategy Annex) always has the long result in mind, a human future that grows and changes with us in a galactic diaspora and beyond. by J. N. Nielsen 0. Introduction: Synchronic and Diachronic Historiography 1. Planetary Constraints upon Civilization...

Into Plutonian Depths

by Paul Gilster | May 28, 2015 | Outer Solar System | 11 Comments

The image of Pluto on the right -- an artist's impression, to be sure (credit: NASA, ESA and G. Bacon, STScI) -- suggests Ganymede to me more than Pluto, but we'll have to wait and see what New Horizons turns up as it continues to close on its target. It's worth thinking about how our views of this place have changed over time. The world found by Clyde Tombaugh seemed small enough when he found it, but a fraction of its light was actually coming from its yet smaller moon, which wouldn't be discovered until USNO astronomer James Christy nailed it in 1978. Gregory Benford depicted Pluto with a nitrogen sea in a 2006 novel called The Sunborn, one in which he explored the possibility of life at -185 degrees Celsius, the lifeforms themselves the result of an experiment by heliopause beings who drew energy from magnetic interactions far from the Sun. Even more speculative is Stephen Baxter's story "Goose Summer" (from the Vacuum Diagrams collection of 2001), in which Plutonian life...

LightSail Glitch: Hoping for a Reboot

by Paul Gilster | May 27, 2015 | Sail Concepts | 18 Comments

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...

Exoplanet Exploration Organization Proposed

by Paul Gilster | May 26, 2015 | Exoplanetary Science | 11 Comments

We've recently looked at the role of small spacecraft, inspired in part by The Planetary Society's LightSail, a CubeSat-based sail mission that launched last week. It's interesting in that regard to consider small missions in the exoplanet realm. ExoplanetSat, for example, is a 3-unit CubeSat designed at MIT as a mission to discover Earth-sized exoplanets around nearby stars. Here the beauty of the CubeSat is obvious: The platform is low-cost, the development time is relatively short, and there are frequent launch opportunities. Up to 100 ExoplanetSats are planned. Pulling big benefits from small packages is not new, as the example of the Canadian MOST mission (Microvariability and Oscillations of STars) reminds us. MOST was the first mission dedicated to asteroseismology, to be followed by CoRoT (COnvection ROtation and planetary Transits) and then Kepler. Now we have a proposal for what is being called the United Quest for Exoplanets (UniQuE), which grows out of work performed by...

A Mass-Radius Relationship for ‘Sub-Neptunes’

by Paul Gilster | May 22, 2015 | Exoplanetary Science | 19 Comments

The cascading numbers of exoplanet discoveries raise questions about how to interpret our data. In particular, what do we do about all those transit finds where we can work out a planet's radius and need to determine its mass? Andrew LePage returns to Centauri Dreams with a look at a new attempt to derive the relationship between mass and radius. Getting this right will be useful as we analyze statistical data to understand how planets form and evolve. LePage is the author of an excellent blog on exoplanetary science called Drew ex Machina, and a senior project scientist at Visidyne, Inc. specializing in the processing and analysis of remote sensing data. By Andrew LePage As anyone with even a passing interest in planetary studies can tell you, we are witnessing an age of planetary discovery unrivaled in the long history of astronomy. Over the last two decades, thousands of extrasolar planets have been discovered using a variety of techniques. The most successful of these to date in...

LightSail Aloft!

by Paul Gilster | May 21, 2015 | Sail Concepts | 12 Comments

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...

Enter the ‘Warm Titan’

by Paul Gilster | May 20, 2015 | Astrobiology and SETI | 25 Comments

Our definition of the habitable zone is water-based, focusing on planetary surfaces warm enough that liquid water can exist there. New work by Steven Benner (Foundation for Applied Molecular Evolution) and colleagues considers other kinds of habitable zones, specifically those supporting hydrocarbons, which can be liquids, solids or gases depending on the ambient temperature and pressure. Benner's work focuses on compounds called ethers that can link together to form polyethers, offering life a chance to emerge and adapt in hydrocarbon environments. Out of this comes the notion of 'warm Titans,' moons with hydrocarbon seas that are not made up of methane. We have no such worlds in our Solar System, and they needn't be moons of gas giants to fit the bill. Think of them, as this Astrobio.net news release does, as being oily Earths drenched in hydrocarbons like propane or octane. Although they do not appear in any genetic molecules on Earth, ethers may be the key to fill the function of...

Exoplanets: The Hunt for Circular Orbits

by Paul Gilster | May 19, 2015 | Exoplanetary Science | 8 Comments

If you're looking for planets that may be habitable, eccentric orbits are a problem. Vary the orbit enough and the surface goes through extreme swings in temperature. In our own Solar System, planets tend to follow circular orbits. In fact, Mercury is the planet with the highest degree of eccentricity, while the other seven planets show a modest value of 0.04 (on a scale where 0 is a completely circular orbit -- Mercury's value is 0.21). But much of our work on exoplanets has revealed gas giant planets with a wide range of eccentricities, and we've even found one (HD 80606b) with an eccentricity of 0.927. As far as I know, this is the current record holder. These values have been measured using radial velocity techniques that most readily detect large planets close to their stars, although there is some evidence for high orbital eccentricities for smaller worlds. Get down into the range of Earth and 'super-Earth' planets, however, and the RV signal is tiny. But a new paper from...

Spacecoach on the Stage

by Paul Gilster | May 18, 2015 | Advanced Rocketry | 32 Comments

I'm glad to see that Brian McConnell will be speaking at the International Space Development Conference in Toronto this week. McConnell, you'll recall, has been working with Centauri Dreams regular Alex Tolley on a model the duo call 'Spacecoach.' It's a crewed spacecraft using solar electric propulsion, one built around the idea of water as propellant. The beauty of the concept is that we normally treat water as 'dead weight' in spacecraft life support systems. It has a single use, critical but heavy and demanding a high toll in propellant. The spacecoach, on the other hand, can use the water it carries for radiation shielding and climate control within the vessel, while crew comfort is drastically enhanced in an environment where water is plentiful and space agriculture a serious option. Along with numerous other benefits that Brian discusses in his recent article A Stagecoach to the Stars, mission costs are sharply reduced by constructing a spaceship that is mostly water....

Doppler Worlds and M-Dwarf Planets

by Paul Gilster | May 15, 2015 | Exoplanetary Science | 14 Comments

Finding small and possibly habitable worlds around M-dwarfs has already proven controversial, as we've seen in recent work on Gliese 581. The existence of Gl 581d, for example, is contested in some circles, but as Guillem Anglada-Escudé argues below, sound methodology turns up a robust signal for the world. Read on to learn why as he discusses the early successes of the Doppler technique and its relevance for future work. Dr. Anglada-Escudé is a physicist and astronomer who did his PhD work at the University of Barcelona on the Gaia/ESA mission, working on the mission simulator and data reduction prototype. His first serious observational venture, using astrometric techniques to detect exoplanets, was with Alan Boss and Alycia Weinberger during a postdoctoral period at the Carnegie Institution for Science. He began working on high-resolution spectroscopy for planet searches around M-stars during that time in collaboration with exoplanet pioneer R. Paul Butler. In a...

Sea Salt in Europa’s Dark Materials?

by Paul Gilster | May 14, 2015 | Outer Solar System | 16 Comments

'Europa in a can' may be the clue to what's happening on Jupiter's most intriguing moon. Created by JPL's Kevin Hand and Robert Carlson, 'Europa in a can' is the nickname for a laboratory setup that mimics conditions on the surface of Europa. It's a micro-environment of extremes, as you would imagine. The temperature in the vacuum chamber is minus 173 degrees Celsius. Moreover, materials within are bombarded with an electron beam that simulates the effects of Jupiter's magnetic field. Ions and electrons strike Europa in a constant bath of radiation. What Hand and Carlson are trying to understand is the nature of the dark material that coats Europa's long fractures and much of the other terrain that is thought to be geologically young. The association with younger terrain would implicate materials that have welled up from within the moon, providing an interesting glimpse of what is assumed to be Europa's ocean. Previous studies have suggested that these discolorations could be...

SETI and Stellar Drift

by Paul Gilster | May 13, 2015 | Astrobiology and SETI | 23 Comments

It was natural enough that Richard Carrigan would come up with the model for what he called ‘Fermi bubbles,’ which I invoked in Monday’s post. A long-time researcher of the infrared sky, Carrigan (Fermi National Accelerator Laboratory, now retired) had mined data from the Infrared Astronomical Satellite (IRAS) in 2009 to mount a search for interesting sources that could be Dyson spheres, entire stars enclosed by a swarm of power stations, or conceivably wrapped entirely by a sphere of material presumably mined from the planetary population of the system. Carrigan’s work on infrared sources goes back well over a decade, involving not only data mining but theorizing about the nature of truly advanced civilizations. If we were to find a civilization transforming a galaxy by gradually building Dyson spheres to exploit all the energies of its stars, we would be witnessing the transformation from Kardashev Type II (a culture that uses all the power of its star) to Type III (a culture that...

« Older Entries

Next Entries »

Charter

In Centauri Dreams, Paul Gilster looks at peer-reviewed research on deep space exploration, with an eye toward interstellar possibilities. For many years this site coordinated its efforts with the Tau Zero Foundation. It now serves as an independent forum for deep space news and ideas. In the logo above, the leftmost star is Alpha Centauri, a triple system closer than any other star, and a primary target for early interstellar probes. To its right is Beta Centauri (not a part of the Alpha Centauri system), with Beta, Gamma, Delta and Epsilon Crucis, stars in the Southern Cross, visible at the far right (image courtesy of Marco Lorenzi).

Now Reading

On Comments

If you'd like to submit a comment for possible publication on Centauri Dreams, I will be glad to consider it. The primary criterion is that comments contribute meaningfully to the debate. Among other criteria for selection: Comments must be on topic, directly related to the post in question, must use appropriate language, and must not be abusive to others. Civility counts. In addition, a valid email address is required for a comment to be considered. Centauri Dreams is emphatically not a soapbox for political or religious views submitted by individuals or organizations. A long form of the policy can be viewed on the Administrative page. The short form is this: If your comment is not on topic and respectful to others, I'm probably not going to run it.

Follow by E-Mail

Advanced Propulsion Research