How realistic is it to have spacecraft brightly illuminated when journeying the solar system?

I’m watching a show on Netflix called Nightflyers and it got me thinking. Every time I watch a show about space travel, they all depict the space crafts cast in darkness; they’re lit, but its dark. So the Moon orbits the Earth, hence we have night and day every 24 hours... but if you’re a craft in space, flying above Earth, and not in the path of the Moon’s orbit, (or perhaps unaffected completely by it as you are no longer on Earth and stuck on its plane) wouldn’t the craft be constantly bombarded with the sun’s rays? (if not disintegrated from the heat all together?) I mean, if you climb a mountain or go snowboarding, even in the most cold places, you can get sunburn as you’re more close to the sun, so I would imagine spacecraft being extremely hot all the time? Can you please help me understand (other than setting a tone, or ambience) how you are affected by light/shade once you are in the solar system? Thanks SO much!
This image from NASA's Cassini spacecraft shows three moons -- Titan, Mimas,  and Rhea. Titan, the largest moon shown here, appear fuzzy because we only see its cloud layers.    Image credit: NASA/JPL-Caltech/Space Science Institute   

This image from NASA's Cassini spacecraft shows three moons -- Titan, Mimas,  and Rhea. Titan, the largest moon shown here, appear fuzzy because we only see its cloud layers. Image credit: NASA/JPL-Caltech/Space Science Institute 

This is a great question, but before we get to the meat of your query, I want to clear up two misconceptions that are present in the question itself. 

The first is that the Moon has something to do with the day/night cycle. Days and nights occur because the Earth is spinning rapidly on its own axis. The Sun, which is relatively stationary with respect to the Earth on the timeframes of a few days, continues to shine from the same point. As the part of the Earth that you or I live on rotates to face towards or away from the Sun, we get day and night respectively. The Moon orbits much, much slower around the Earth - approximately once every month. The Moon can occasionally cast a shadow onto the Earth, but that’s a rare event we know as a solar eclipse. 

The second is why you sunburn at altitude. You absolutely are more prone to sunburns at higher altitudes, but it’s not because you’re significantly closer to the Sun. The Sun is 93 million miles away - getting a single mile or two closer isn’t going to make a significant change to the amount of sunlight that your skin’s getting. What happens instead is that you’re rising above some of the protective layer of our atmosphere, which allows more ultraviolet radiation to reach you. This UV radiation is what triggers a sunburn, and the more atmosphere above you, the more protected you are. If you’re on a snowy mountain, you have the additional complication of being able to get sunburned in really strange places, like the underside of your earlobes and the bottom of your chin, because of the reflected light off of the snow.

This image of a crescent Jupiter and the iconic Great Red Spot was  created by a citizen scientist (Roman Tkachenko) using data from Juno's JunoCam instrument.    Image credit: NASA/JPL-Caltech/SwRI/MSSS/Roman Tkachenko   

This image of a crescent Jupiter and the iconic Great Red Spot was  created by a citizen scientist (Roman Tkachenko) using data from Juno's JunoCam instrument. Image credit: NASA/JPL-Caltech/SwRI/MSSS/Roman Tkachenko 

With those two points addressed, your question about lighting in space is an excellent one. There’s a couple things to think about with lighting, so let’s begin with a spacecraft which is near the Earth. If you are in a position where nothing is blocking the sunlight coming your way, you would be constantly bombarded by the Sun’s rays, exactly as you suspect. However, this is an extremely harsh lighting system - with no atmosphere in space to diffuse the light a little, spacecraft are in pure sunlight or deepest shade. If a spacecraft is moving around the Sun, that means that the sunward facing side of the spacecraft would be illuminated, and the other half of your spacecraft would be in shadow - triggering a pretty intensive temperature gradient between the two sides. As a point of reference, the temperature on the surface of the Moon swings between 224F (106C)  and negative 298F (-183C) when the surface is illuminated versus when it is in shadow. 

This temperature cycling causes stress on most materials you could build a spacecraft out of, and is a challenge we face already as a moderately spacefaring species. The International Space Station, which orbits around the Earth, alternates between spending 45 minutes in the shadow of the Earth and 45 minutes in direct sunlight. Without intensive, intensive insulation, our astronauts would alternate between freezing to death and boiling to death. We have to manage this same situation on a smaller scale for space suits; in the sunlight, your suit has to keep you cool and protect your eyes from glare. In the shadows, it must keep you warm.

These considerations will only get worse as you get closer to the Sun, or really around any star. As we proceed inwards, closer to the sun, the sunlight gets more intense, and the amount of work you’d need to do to stay cool would increase. The cool side of your craft wouldn’t get any colder, but the temperature stress would get more severe between the sun and shaded sides of your craft, so your insulation would have to get much better.  This intensity doesn’t change linearly though - if you got twice as close to the star, the sunlight won’t be twice as intense. It will be four times as intense. 

This works just as well in the other direction - go twice as far out in the solar system, and your sunlight will drop off by a factor of four. Go four times as far, and you’re dealing with light intensity 16 times fainter than you have at the distance of the Earth. However, the Sun is very bright. Jupiter is 5.2 au - and Neptune at 30 au. At 5.2 au, you’re dealing with sunlight 27 times fainter than what we receive on Earth. It’s still going to be the brightest thing in the sky. Neptune is much further, but even at 900 times fainter than the Sun appears from an Earth distance away, it still hasn’t faded to anywhere near the relative faintness of the full moon in the sky, and you can do a lot in the light of a full moon, visibility wise. 

Crescent Neptune and Triton.    Image credit: Voyager 2, NASA

Crescent Neptune and Triton. Image credit: Voyager 2, NASA

The way that astronomers measure brightness is with a counterintuitive system called a magnitude, where 1 magnitude is about a factor of 2.5 in brightness. Every magnitude is multiplicative, so five magnitudes is a difference in brightness of a factor of 100. A difference of ten magnitudes is a factor of 10,000 in brightness. At Jupiter’s distance, then, the Sun will appear about 3.6 magnitudes fainter than it does from the Earth. At Neptune’s distance, it’s something like 7.5 magnitudes fainter. The brightest star in the night sky, Sirius, is 25 magnitudes fainter than the Sun, so even at the distance of Neptune, the Sun will appear more than 10 million times brighter than Sirius appears on Earth. The full Moon, which I mentioned earlier, is fourteen magnitudes fainter than the Sun, so the Sun would be shining on Neptune about 390 times more intensely than the full moon. 

If your fictional craft is within the bounds of a solar system then, I’d say having the craft be brightly illuminated on one side is pretty reasonable. If you’re going beyond that, though, you’d start to descend into full darkness. You’d have to be very far away from our star before the Sun sank to the brightness of Sirius. In fact, you’d need to be almost 1.5 light years away from our star. The spaces within the stars, which is the majority of the Milky Way Galaxy, are going to be very dark. In those places, the only bright lights will be the ones you bring with you. You probably would want to have a few spotlights around, if any of the crew ever has to go outside for any kind of repair operations, but it wouldn’t have the same aesthetics as the harshly lit side of a spacecraft that many shows like to go for. 


Have your own question? Feel free to ask! You can also submit your questions via the sidebarFacebook, or twitter. Sign up for the mailing list for updates & news straight to your inbox!

This site is reader supported! To support it, you can become a patron on Patreon, which gives you early access to this article. You can also make a one-time donation via Ko-Fi! Or, consider buying the book!

Why do we always think of North as up?

Hi! It might be a dumb question but it’s been in my mind for a while. We are convinced that North is up and South is down because that’s the way maps have been for many many years, but we don’t really know which way is actually up, it could be east or northwest, etc, right? Because there isn’t a real orientation/position in space, there’s no fixed up or down, but... doesn’t the way the Earth rotate determine in a way which way is up? How do those two things related to each other? Or is there no connection at all? Thank you!
"The Blue Marble" is a famous photograph of the Earth taken on December 7, 1972, by the crew of the Apollo 17 spacecraft en route to the Moon at a distance of about 29,000 kilometres (18,000 mi). It shows Africa, Antarctica, and the Arabian Peninsula. In this version, it has been flipped upside down, with South at the top of the image. Image credit:  NASA

"The Blue Marble" is a famous photograph of the Earth taken on December 7, 1972, by the crew of the Apollo 17 spacecraft en route to the Moon at a distance of about 29,000 kilometres (18,000 mi). It shows Africa, Antarctica, and the Arabian Peninsula. In this version, it has been flipped upside down, with South at the top of the image. Image credit: NASA

You’re right that the way we draw our maps with North pointing up and South pointing down is largely arbitrary, and indeed there are a number of maps with the Southerly direction at the top rather than at the bottom, and they’re good fun to look at However, there are good reasons to say that a Northerly or Southerly direction should be “up”, and these reasons extend beyond just the rotation of the Earth.

The rotation of the Earth is a good starting place, though - the rotation axis of the Earth goes more or less through the North and South magnetic poles of the Earth. The magnetic North & South poles wander a little, so some years they’re closer to the rotation axis than others. Fixing the rotation of the Earth as a cardinal direction makes good sense, and is what we’ve done - East and West point 90 degrees from North and South.

There’s one more reason to put North as up, and it’s a physics convention. Most of the time, when we’re talking about rotation, we say that the direction of the rotation axis is actually just in one direction, rather than having to indicate both North and South. If we do this, it allows us to encode both the axis of rotation, and the direction of rotation at the same time. The way we determine which of North or South should be “the direction”, we use what’s called the “right hand rule”. You curl your fingers in the direction of rotation, and your thumb points in the direction of the rotation axis. In the Earth’s case, we rotate towards the East, so your thumb will point in the direction of North.

A drawing of the solar system shows Pluto's tilted orbit. Pluto's orbital path angles 17 degrees above the line, or plane, where the eight planets orbit. Credits:  NASA

A drawing of the solar system shows Pluto's tilted orbit. Pluto's orbital path angles 17 degrees above the line, or plane, where the eight planets orbit. Credits: NASA

However, if you’re thinking of orientations beyond just the Earth’s own rotation, while it’s true that there’s no way to set an entirely objective zero point from which to measure other positions, and a sphere doesn’t have much intrinsic orientation to it, we can still do relative positions pretty well. And on the scale of our solar system, we have a pretty solid alignment going on. All the major planets in our solar system trace oval paths around the Sun as they go about their respective years. Not only do they orbit around the Sun in the same direction, they all tend to point their rotation axes in the same direction (notable exceptions here are Venus and Uranus). On top of all that, the ovals are almost perfectly aligned in a flat plane. If we take our same physics convention and use the rotation of the planets around the Sun to tell us which direction we’re going to point up, our Planet Earth based North is more or less pointing in the right direction. Our planet’s spin is not perfectly aligned with the “up” out of the solar system, but tilted by 23 degrees, a feature of our planet responsible for our seasons. This tilt is why many globes are set at an angle - they’re mimicking the tilt of our planet relative to the “up” defined by our solar system.

So the North is up convention is partially mapmakers, partially the spin of our Earth, and partially physics notation, but there are definite ties between all of them.


Have your own question? Feel free to ask! Or submit your questions via the sidebarFacebook, or twitter.

Sign up for the mailing list for updates & news straight to your inbox! Astroquizzical is now a bookCheck here for details & where to order!

What Do We Encounter Going Straight Up Out Of The Solar System?

So if our solar system is more or less flat in terms of the planetary rotations around the sun (I’m using typical pictorial depictions of the solar system), what is up and down from our solar system and galaxies? It doesn’t seem like above and below of light years in space is ever explored. Or are the (for example) constellations examples of up and down in space?
"Draco and Ursa Minor", plate 1 in Urania's Mirror, a set of celestial cards accompanied by A familiar treatise on astronomy. Jehoshaphat Aspin,  Public domain

"Draco and Ursa Minor", plate 1 in Urania's Mirror, a set of celestial cards accompanied by A familiar treatise on astronomy. Jehoshaphat Aspin, Public domain

Originally posted on Forbes! 

The solar system is indeed pretty much a flat sheet, with the major planets all orbiting in a very thin plane surrounding the Sun. Part of the reason we don’t tend to send spacecraft in the 'up' direction, out of this thin plane, is simply that there’s not very much...

The solar system is indeed pretty much a flat sheet, with the major planets all orbiting in a very thin plane surrounding the Sun. Part of the reason we don’t tend to send spacecraft in the 'up' direction, out of this thin plane, is simply that there’s not very much there! Now, that’s not to say that there isn’t anything out that direction, but you have to travel for a while before you reach it.

Closest to the solar system, but at its outermost fringes, the orbits of the objects in the Kuiper Belt deviate from this extremely flat plane, but still tend to orbit mostly in a disk surrounding the Sun. Instead of an extremely flat plane, you have something more like an inner tube - inflated, with some vertical height to it, but still mostly lining up along the plane of the rest of the major planets. This area is where Pluto falls - its orbit is tilted out of the plane of the major planets by 17 degrees, but it’s not so far tilted out of the plane of the rest of the planets that it’s really traveling overhead the other planets.

A drawing of the solar system shows Pluto's tilted orbit. Pluto's path is angled 17 degrees above the line, or plane, where the eight planets orbit. Pluto's orbit is more elliptical than the planets’ paths. Image credit: NASA

A drawing of the solar system shows Pluto's tilted orbit. Pluto's path is angled 17 degrees above the line, or plane, where the eight planets orbit. Pluto's orbit is more elliptical than the planets’ paths. Image credit: NASA

What you do get overhead the planets is a much more distant object, the Oort Cloud. This is a reservoir of comets, incredibly distant from the Sun, which are arranged in a roughly spherical distribution around the Sun. The objects out here are small, dimly lit chunks of ice and rock, and so far from the Sun that they are extremely difficult to observe, even with high end telescopes.

If we travel further away, and look for even more distant objects, then suddenly we run into a proliferation of stars within our own galaxy which are 'up' above the plane of our solar system. Part of this is that the galaxy is much thicker than the solar system, and so even if the plane of the galaxy and the plane of the solar system were perfectly aligned, we would see stellar neighbors of our Sun, both above and below our solar system. However, our solar system isn’t perfectly well aligned with the Milky Way galaxy- those two are off from each other by 63 degrees. What this means is that we see far more stars 'up' or 'down' out of our solar system, as we look through part of the densely populated disk of the galaxy, than we would if we were looking directly 'up' out of the plane of the galaxy.

A star chart oriented so that the center of the image is directly perpendicular to the plane of the solar system. The constellation Draco falls in the center of the image, with the Little Dipper slightly to the right of center. Image credit: Tom Ruen, public domain

A star chart oriented so that the center of the image is directly perpendicular to the plane of the solar system. The constellation Draco falls in the center of the image, with the Little Dipper slightly to the right of center. Image credit: Tom Ruen, public domain

The constellations are a good example of things that exist 'above' our solar system. Our planet spins on an axis that’s tilted by 23 degrees relative to the plane of the solar system, so looking at the stars at the exact North Pole isn’t quite pointing us in the right direction, but it’s pretty close! If you find the North Star, Polaris, and then wander about twenty degrees (about two fists, held at arm’s length at the sky) away from the path the Moon travels, now you’re pointing 'up' out of the solar system. The constellations in this region of the sky are plentiful. This is roughly where the cup of the Little Dipper is, though exactly 'up' is in the much fainter constellation Draco (illustrated at the top of the article). The stars that hang 'above' our planet remain roughly stationary in our night skies as our planet rotates beneath them - if you’re far enough North these stars will never set.

Since the direction of 'up' away from the solar system doesn’t also point you directly out of the Galaxy, if you want to face a direction that aims you at the center of the galaxy or 'up' out of the Galaxy, you need to point yourself in a different direction.  The center of the galaxy is in the direction of the Sagittarius constellation, which looks a bit like a very pointy teapot in the sky. To point your face out of the galaxy, you must aim yourself at the lesser-known constellation Coma Berenices, which is surrounded by other constellations you’ve probably heard of - Virgo and Leo border it, as does Ursa Major (which contains the Big Dipper). If you take the last three stars in the curve of the handle of the Big Dipper, and imagine them creating a long, pointy pizza wedge, you’ve gotten pretty close to Coma Berenices. What's in that direction? Not much that's visible to the naked eye, but if you have a well-equipped telescope, you run into the Coma Cluster, a very dense collection of galaxies - an environment very unlike the galaxy our own Milky Way finds itself within. 

Have your own question? Feel free to ask! Or submit your questions via the sidebarFacebook, or twitter.

Sign up for the mailing list for updates & news straight to your inbox! Astroquizzical is becoming a bookCheck here for details & where to preorder.

How Come The Oort Cloud Isn't Torn Away From Our Sun By Nearby Stars?

If the Oort Cloud is three light years away from our Sun, then it’s closer to Alpha Centauri than our Sun, right? So how can it stay around our Sun if the mass of Alpha Centauri is 1.1 times the mass of our Sun - wouldn’t the gravity of Alpha Centauri rip it away?
An illustration of the Kuiper Belt and Oort Cloud in relation to our solar system. Image credit: NASA

An illustration of the Kuiper Belt and Oort Cloud in relation to our solar system. Image credit: NASA

Originally posted on Forbes!

The Oort cloud is an interesting feature of our solar system; a nebulous, spherical cloud of comets which marks the very outer limit of our solar system. The Oort cloud is also the source of our long period comets - those icy fragments of the early solar system which orbit our Sun very infrequently. To be classified as a long period comet, more than 200 years must pass between trips near the Sun. Hale-Bopp is probably the most well known of these, as it was visible to the naked eye for a long time in 1998. A more recent visitor was the Lovejoy comet, which swung near the Sun in 2011.

The Oort cloud is very far from the Sun. It is outside the bubble produced by our Sun’s solar wind and magnetic field by a considerable distance. While Voyager 1 has left this magnetic bubble, and entered what is called “interstellar space”, it has several hundred more years of traveling before it even reaches the inner edge of the Oort cloud. How is part of the solar system in interstellar space? Well, this means that the solar system at such a large distance from the Sun is not entirely ruled by our own star - the presence of other stars is mixing with the influence of our Sun.

This artist's concept puts solar system distances in perspective. The scale bar is in astronomical units, with each set distance beyond 1 AU representing 10 times the previous distance. The inner edge of the main part of the Oort Cloud could be as close as 1,000 AU from our sun. The outer edge is estimated to be around 100,000 AU. Image credit: NASA/JPL-Caltech

This artist's concept puts solar system distances in perspective. The scale bar is in astronomical units, with each set distance beyond 1 AU representing 10 times the previous distance. The inner edge of the main part of the Oort Cloud could be as close as 1,000 AU from our sun. The outer edge is estimated to be around 100,000 AU. Image credit: NASA/JPL-Caltech

The inner edge of the Oort cloud is typically quoted as beginning at somewhere between 1,000 and 5,000 au from the Sun. 5,000 au is about 0.08 light years away from the Sun, which is a little over four weeks of travel time for a beam of light, and considerably closer to our Sun than to Proxima Centauri, the closest star. These Oort cloud objects at the inner edge of their cloud are fairly reasonably more attached to our Sun than they are to anything else, and there are a lot of them here.

As we travel from the inner Oort cloud to the outer region, we should note that the Oort cloud is not an even assembly of objects, from some inner bound to a fixed outer bound. Instead, while there is something of an inner boundary, the outer boundary is more of a fizzling out, with objects getting fewer and farther between as you go farther and farther from the Sun. This means that the “outer boundary” is a very tricky thing to attach a number to. How many objects need to be out there to still count as part of the Oort cloud? Just one? Or do we need a higher density of objects before we’re dropping our delineation down? As a result of this fuzziness, plus the fact that it’s very hard to spot Oort cloud objects in the first place, estimates of the outer bound of the Oort cloud range from 50,000 to 200,000 au. It’s that 200,000 au that works out to 3.1 light years away from our Sun. NASA often quotes this outer edge as sitting at 100,000 au, which is about 1.6 light years, which means that this fuzzy “edge” is extending less than half the way out to Alpha Centauri.

Comet Lovejoy is visible near Earth's horizon in this nighttime image photographed by NASA astronaut Dan Burbank, Expedition 30 commander, onboard the International Space Station on Dec. 22, 2011. Image credit: NASA

Comet Lovejoy is visible near Earth's horizon in this nighttime image photographed by NASA astronaut Dan Burbank, Expedition 30 commander, onboard the International Space Station on Dec. 22, 2011. Image credit: NASA

All these numbers are for a sense of scale. In actual fact, the Oort cloud is incredibly sensitive to gravitational forces from objects other than our Sun. One of these is a very large-scale gravitational inequality; our solar system is not at the center of the Milky Way galaxy. The gravitational pull from our Galaxy is therefore stronger on one side of the solar system than it is on the other, and this galactic tide is enough to gradually jostle the Oort cloud. This kind of perturbation is part of how we think we get the long period comets, which can come blazing into the inner solar system, and, if they are unlucky, sometimes completely evaporated by the Sun.

The Oort cloud is also sensitive to the motions of other stars nearby in the Galaxy, and other extrasolar objects, like clouds of gas. As stars pass nearby (or through) the outer reaches of the Oort cloud, they will disturb the delicate gravitational balance that keeps these objects in their long, distant orbits. Stars aren’t likely to smash directly into a comet out there, but they might jostle it out of its orbit, and send it down into the inner solar system - another way of getting comets into the rest of the solar system.

Comet Hale-Bopp. Alex Krainov shot this image at Zabriskie Point in Death Valley in April 1997. Image credit: Alex Krainov, CC BY-SA 3.0

Comet Hale-Bopp. Alex Krainov shot this image at Zabriskie Point in Death Valley in April 1997. Image credit: Alex Krainov, CC BY-SA 3.0

But these perturbing stars are in motion too, and they will pass through relatively quickly, on an astronomical timescale. Alpha Centauri is still arriving into the solar neighborhood, and isn't yet close enough to do much influencing. With the combination of the fading density of objects, the short time frame with which a star will be close enough to really dramatically pull on the objects sitting out there, and the length of time between stellar close passes being quite long, we don't expect the Oort cloud to have been stripped away from our star. But it is absolutely influenced by the presence of those stars, and by the Galaxy at large, and our long, once-a-millennia comets like Hale-Bopp are the result.

Have your own question? Feel free to ask! Or submit your questions via the sidebarFacebook, or twitter.

Sign up for the mailing list for updates & news straight to your inbox!

Are There Any Planned Missions Using Solar Sails?

Are there any planned planetary missions using solar sails for propulsion?
This is a picture of the Sunjammer solar sail being tested, before the project was canceled. Image Credit: NASA/L'Garde

This is a picture of the Sunjammer solar sail being tested, before the project was canceled. Image Credit: NASA/L'Garde

Originally posted at Forbes!

There aren’t very many, but there are a few! I’ve poked around and found three major projects which are actively being worked on, though there have been more than that in the past, or which were tested on the ground, and never made it to space.  If you’re curious to learn about how solar sails work, exactly, check out this post which covered just that!

The solar sail project that might be most familiar to you is the LightSail, brought to you by the people at the Planetary Society. Because the Planetary Society is not a government agency, they’re free to fund their missions however they please, and the LightSail wound up being significantly funded by a Kickstarter campaign. The LightSail Kickstarter in 2015 coincided with their proof-of-concept solar sail deployment test; this was a quick orbit around the planet, just long enough to deploy it from its launch rocket, check that the sail could unfurl as expected, and grab a quick image of itself. The Kickstarter was a tremendous success, raising a million more than their goal of $200,000, meant to help pay for the last bit of unfunded construction and launch costs. Since the proof-of-concept craft worked almost perfectly (there were a few communication glitches), the Planetary Society is going forward with their first full-scale solar sail mission, which should leave the Earth’s atmosphere and hitch a ride on our Sun’s solar wind.

Artist's impression of a solar sail beginning its journey, accelerated (slowly) by the solar winds. Image credit: Kevin Gill, CC A-SA 2.0

Artist's impression of a solar sail beginning its journey, accelerated (slowly) by the solar winds. Image credit: Kevin Gill, CC A-SA 2.0

The LightSail 2, as the next one will be called, is scheduled to launch this year, on a SpaceX Falcon Heavy rocket. The LightSail is still in pretty early days, in terms of what kind of science it’s doing - the next launch is primarily to check that the light sail of its size works the way we think it should, and can successfully accelerate a small craft away from the Earth. As each incarnation of the LightSail succeeds, the scientific scope of the missions will increase- which makes sense, you don’t want to put an expensive scientific instrument on a craft if you’re still worried about the craft being able to spread its wings.

The most successful solar sail to date was launched in 2010, by the Japanese space agency JAXA. IKAROS, which stood for Interplanetary Kite-craft Accelerated by Radiation Of the Sun, was launched along with Akatsuki, their craft currently orbiting Venus. IKAROS successfully opened up, and formally operated as a light sail, gaining speed from the solar wind. IKAROS had a few science instruments aboard - a gamma ray burst detector and a dust particle counter. IKAROS was cleverly also equipped with small solar panels embedded in the sail, which provided power to the satellite. IKAROS surpassed its initial mission timeline, which was 6 months, and continued to communicate with Earth (with exceptions for its hibernation periods when the sunlight was too weak to power its instruments) until 2015.

The Japan Aerospace Exploration Agency (JAXA) successfully took images of the whole solar sail of the Small Solar Power Sail Demonstrator "IKAROS" after its deployment of a separation camera* on June 15 (Japan Standard Time, JST.) The IKAROS was launched on May 21, 2010 (JST) from the Tanegashima Space Center. Image credit: JAXA

The Japan Aerospace Exploration Agency (JAXA) successfully took images of the whole solar sail of the Small Solar Power Sail Demonstrator "IKAROS" after its deployment of a separation camera* on June 15 (Japan Standard Time, JST.) The IKAROS was launched on May 21, 2010 (JST) from the Tanegashima Space Center. Image credit: JAXA

JAXA is planning to launch a much bigger solar sail around 2020. This craft is scheduled to head off to investigate a set of asteroids which share an orbit with Jupiter, making a return trip with a small chunk of an asteroid sometime in 2050. Where IKAROS was 14 meters to a side (by no means small), this new solar sailboat will be 50 meters per side - more than three times the collecting area. JAXA recently showed off a full-sized model of one of its four wings, which took their volunteers a careful 10 minutes to unfold.

The last major ongoing solar sail project is Breakthrough Starshot, but it’s both the one which is aiming the highest, and the least far along in its progress to launch. They’re hoping to construct a solar sail which could be accelerated not just by the solar wind, but by high powered lasers, with the aim of getting a craft near Alpha Centauri in ~20 years. This is ambitious, to put it kindly, and the folks at Breakthrough Starshot are well aware. They have an entire page dedicated to major challenges that we don’t yet know how to solve.

As the technology develops for solar sails, they will become cheaper and easier to produce. I suspect we will start seeing more people attaching them to nanosats and cubesats which are relatively cheap to create and launch!

Have your own question? Feel free to ask! Or submit your questions via the sidebarFacebook, or twitter.

Sign up for the mailing list for updates & news straight to your inbox!