The news that The Planetary Society is readying the first of its Lightsail spacecraft for a May launch stirs memories of Cordwainer Smith (Paul Linebarger) and mainframe computers. Smith wrote his haunting science fiction in the days when computers filled entire rooms, and the pilot who flies a solar sail thousands of kilometers wide in “The Lady Who Sailed the Soul” is there because, as a technician tells her, “…a sailor takes a lot less weight than a machine. There is no all-purpose computer built that weighs as little as a hundred and fifty pounds. You do. You go simply because you are expendable.”
Despite the anachronisms, Smith’s short stories (collected in The Rediscovery of Man) are as mesmerizing as ever. As computers were big in those days, so have been our sail designs, from Smith’s behemoth (towing 26,000 adiabatic pods containing frozen human settlers) to Robert Forward’s beamed-laser sails. Given the need for harnessing the momentum of photons, all this makes sense, but we’re learning how many interesting things we can do with much smaller sails, like NASA’s NanoSail-D, an experiment in sail deployment and de-orbiting payloads that was a scant 10-meters square. LightSail, in sail terms, is still quite small, with a combined area of 32 square meters.
Both NanoSail-D and LightSail take advantage of the wild card technology of recent times, the CubeSat, which allows sails to be packed into containers no larger than a loaf of bread. Each of the mylar sails aboard the LightSail mission — there are four of them — is about 4.5 microns thick, deploying from four metallic booms that gradually unwind to unfold the triangular sail panels. The craft will use three electromagnetic torque rods to interact with the Earth’s magnetic field to maintain proper orientation. After sail deployment, ground-based lasers will measure the solar photon effect.
Image: LightSail-1 fully deployed. The mission is a precursor to a later LightSail mission to test true solar sailing in a much higher orbit. Credit: Josh Spradling/The Planetary Society.
The Planetary Society is calling this mission a ‘shakedown cruise,’ one that will allow scientists to test out the basic functions of the mission in preparation for the launch of a second LightSail in 2016 aboard a SpaceX Falcon Heavy. A four-week checkout period will be followed by sail deployment, after which, because of its low orbit, the craft will be pulled within days back into the atmosphere. Even so, we should get interesting views of the deployment through LightSail’s two inward-facing cameras, offering time-lapse imagery of the sail’s brief period of operations.
In Jason Davis’ recent article on LightSail, he notes a fact that many of us vividly recall. It will be ten years this June since the Russian Volna rocket carrying The Planetary Society’s Cosmos 1 failed in its attempt to lift the sail to orbit. That left the Japanese space agency JAXA to win the honor of achieving the world’s first operational solar sail when it launched IKAROS in 2010. But interest in small sail technology remains intense, with NASA planning both NEA Scout and Lunar Flashlight for launch in 2018. Both are CubeSat-based, though with larger sails than LightSail. For more on sail projects now in development, see A Near-Term Sail Niche. Note as well that The Planetary Society has created a new website for the two LightSail missions.
But even 85-square meter sails like NEA Scout and Lunar Flashlight are tiny compared to the 1000-kilometer lightsail Robert Forward envisioned for a manned mission to Epsilon Eridani. Can we really do worthwhile science with sails this small? The answer is a resounding yes. By reducing payload mass and maximizing the power of miniaturization, CubeSats give us options like ‘swarm’ missions to the outer Solar System that could be enabled by sail technologies. This could be a low-cost approach to deepening our knowledge of places we’ve only seen in flybys.
So as we continue work on larger designs, let’s see what we can learn from small sails close to home. When LightSail deploys, I’ll probably go back and re-read “The Lady Who Sailed the Soul,” where Cordwainer Smith describes “…the great sails, tissue-metal wings with which the bodies of people finally fluttered out among the stars.” Our CubeSat sails are early steps along the road to the great ships of Smith, Robert Forward and all the researchers who have seen the promise of sunlight and beamed energy as ways to push our payloads into the cosmos.
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Paul Gilster wrote in the main article:
“The news that The Planetary Society is readying the first of its Lightsail spacecraft for a May launch stirs memories of Cordwainer Smith (Paul Linebarger) and mainframe computers. Smith wrote his haunting science fiction in the days when computers filled entire rooms, and the pilot who flies a solar sail thousands of kilometers wide in “The Lady Who Sailed the Soul” is there because, as a technician tells her, “…a sailor takes a lot less weight than a machine. There is no all-purpose computer built that weighs as little as a hundred and fifty pounds. You do. You go simply because you are expendable.”
I am reminded of the Arthur C. Clarke story likely from the 1950s about an interstellar war where the battleships relied on a special vessel that carried all their computing equipment. You knew it was powerful because it user over one million vacuum tubes to crunch numbers!
As machines of various types become smaller and more sophisticated, the need for actual humans aboard space vessels outside of deliberate colonization comes more into question. I know this isn’t always popular with real astronauts and wannabe space travelers, but it takes a lot to support a person in space.
If we are sincerely interested in exploring the Universe plus keeping the bean counters from blocking our paths to space, we need to take seriously the fact that machines can do it better and cheaper. Just look at the Mars rover Opportunity as it goes into its eleventh year exploring the Red Planet and ask yourself how much it would have cost to keep a human on Mars doing the same task and whether he or she could have survived for so long there by themselves or would it have happened at all if we needed to wait for humans to do our space exploring.
@ ljk. The main arguments for humans is that they can do a lit more, more flexibly and faster than machines. Howeve, assuming we can build good general AI and embody it, that argument tends to lose potency. When that might be I don’t know, but I doubt more than a century at worst. What form those machines might take could be anything from Asimovian humanoid robots to something completely alien to us today.
Anytime I see Cordwainer Smith’s name always triggers a voice in my brain.
I remember reading “Scanners Live in Vain” in a used copy of Fred Pohl’s Beyond the End of Time in maybe 1955. I had been reading science fiction for almost 3 years at that time. I remember it being so strange that I could not figure it out! I did not read it again for maybe 10 more years , when I had read thousands of pages of SF , this time it took my breath away! I have read everything Cordwainer Smith wrote , at this late date, many thousands more page of SF prose, I can say I have never read anything like him, no one has ever written anything like it nor do I think anyone else will! All you have to do is read the titles:
No, No, Not Rogov!
Alpha Ralpha Boulevard
Think Blue, Count Two
The Ballad of Lost C’Mell
Just to mention four, the titles seem clever word play, but the stories are strange and stylish other worldly ‘future fiction’ SF.
One of my favorites posed this problem : what kind of planetary defense do you mount in order to protect a planet what possess the most sought after , valuable beyond measure substance in the entire galaxy?
Smith solved that problem with story called “Mother Hitton’s Littul Kittons” which left my mind reeling!
For the most part it does seem that unmanned probes can do most of the ‘science missions’ – if not all – that we could plan. And this is only going to become more true as computer become more powerful and we draw closer to the elusive goal of AI. However, there will be a point were we will send manned missions out, although we may wait a long time before spaceflight technology makes it easy enough. Realistically, we send out probes because we are curious, and to stand on the surface of another world is the ultimate answer to that curiostity. But, as I said, it could be a very long time…
By reducing payload mass and maximizing the power of miniaturization, CubeSats give us options like ‘swarm’ missions to the outer Solar System that could be enabled by sail technologies.
Moore’s Law still continues despite claims that it must end soon. Despite suggestions that general AI won’t ever happen, we’ve seen a powerful approach with Deep Learning that has made large improvements in a number of domains. Clever techniques also allow miniaturized sensors and other hardware to provide the performance of much larger instruments.
As Feynman said, “There is plenty of room at the bottom”. How far can miniaturization go?
This could be a low-cost approach to deepening our knowledge of places we’ve only seen in flybys.
I heartily agree. Each wave of miniaturized technology reduces costs and enhances our capabilities. One day launching low cost probes to the outer worlds will be personally affordable. It would be exciting is this was possible sometime this century.
My question is when will such technology impact thinking for the 100 year star ship project?
Looking forward to the launch of Light-Sail-1.
Also, happy to see that NASA is working on a large P-V array to power electrical propulsion engines with manned vehicle capacities.
As at least a former Planetary Society member (I think I need to renew my membership), I am pleased that folks are once again emphasizing the power of light.
@alex: “but I doubt more than a century at worst”: then maybe the window for humans in spacecraft is a relatively narrow 100 years.
then maybe when we do make contact (or more likely, the ETIs contact us), it’ll most likely be machines (either as representatives of carbon species, or as the primary species themselves, or as one species from a multispecies collective).
@Alex Tolley on humanoid robots:
I’m a machine! And I can know much more! I can experience so much more. But I’m trapped in this absurd body! And why? Because my creators thought that God wanted it that way!
Al Jackson writes (about Cordwainer Smith):
And Al, don’t forget “Golden the Ship Was – Oh! Oh! Oh!” I’ll never forget that one in a 1959 issue of Cele Goldsmith’s Amazing. It was my introduction to the extraordinary Cordwainer Smith.
Robots have a bright future in space. They’re ideal for working out there, while an astronaut needs a costly life support system. The main advantage of an astronaut is having more skills than a machine, but as robots and remote controls improve, that will make less of a difference. Other than that, there’s the romantic idea of “going where no man has gone before” but science/technology/economy must come first in building our future.
Lightsail technology gets more impressive in our times than in previous generations. Besides its principal utilization for propulsion, lightsails can be integrated for space based electric power utilization?
Lightsails could be highly effective for mission inside of Earth’s orbit.
If I was doing station keeping around Venus or Mercury…. Even close approaches around the Sun…. I’d like to take advantage of solar power to run
air-conditioning and breathable gas recycling.
Potentially, lightsails have been proposed that could get manned craft to relativistic speeds? 80 weeks at .9 g gets values up to .91 c ?
The terra watts per square centimeter would be mind blowing… 5 year trips to the center of the Milky way… 12 years to Andromeda…. Earth would have rest aged about 30Kiloyears or 2.2 Megayears
… but it starts an ambitious dialogue about exploration.
It’s up there with sending dying people towards the event horizon of a black hole.
I would be tempted to go?
Tom February 6, 2015 at 8:03
‘The terra watts per square centimeter would be mind blowing’
That amount of energy vapourises everything in short order.
‘It’s up there with sending dying people towards the event horizon of a black hole.
I would be tempted to go?’
On seeing how matter is shreaded near the event horizon it goes without saying you would be long dead before you ever saw what was on the other side.
LightSail Arrives in Florida; More Launch Details Revealed
Posted by Jason Davis
2015/03/09 21:32 UTC
A cadre of CubeSats including The Planetary Society’s LightSail spacecraft completed a cross-country journey from California to Florida, where they await installation as a secondary payload aboard an Atlas V rocket. NASA and the U.S. Air Force also released the nomenclature of the rocket’s primary and secondary payloads, and a preliminary launch date has been set for May 6.
Full article with images here:
The Planetary Society is finalizing a web dashboard that will display LightSail’s ground track and telemetry data. The data will include temperature readings, power levels and rotation rates as LightSail soars around the globe, stabilizing itself using Earth’s magnetic field.
While LightSail will not be visible to the naked eye during its four-week checkout phase, it may be viewable from some locations around dawn and dusk after the sails are deployed. Visitors to the LightSail dashboard will receive predictions on when the spacecraft will be visible from their location. However, due to atmospheric drag, the 2015 test mission is expected to end just two to ten days after sail deployment.
Meanwhile, work progresses on the Society’s second LightSail spacecraft, dubbed LightSail-B, which will fly to a circular, 720-kilometer orbit in 2016—high enough to demonstrate controlled solar sailing and create more viewing opportunities. LightSail-B will be paired with Prox-1, a small Georgia Tech spacecraft designed to demonstrate automated rendezvous and inspection techniques.