2 years ago the Kepler probe was dealt a critical blow. Out of 4 reaction wheels, the devices which keep the telescope pointed in the right direction, only 2 remained functioning. This meant that the telescope was no longer able to maintain the level of precision required to continue its planet hunting mission. However there was a bold plan to continue Kepler’s mission, albeit in rather different capacity. Kepler could use the solar pressure exerted by our sun as a third reaction wheel, allowing it to continue imaging the sky and looking for planets. It wouldn’t be able to look at the same piece of sky for the entire time however and would be limited to viewing periods of approximately 80 days each.
Whilst this was a significant downgrade in Kepler’s abilities it was a far better option than just retiring the spacecraft completely. In its previous incarnation Kepler was able to track hundreds of thousands of stars continuously, allowing us to detect numerous planets orbiting their parent stars. In its current incarnation Kepler will only be able to detect planets with shorter orbits which are unlikely to be the Earth-like ones we’re all hoping for. Still even in that reduced capacity Kepler has been able to identify no less than 100 new exoplanets with over 200 additional candidates awaiting confirmation by other methods. For a telescope that may have been written off that’s an amazing accomplishment, but it doesn’t just stop there.
As the above diagram shows Kepler has to reorient itself every so often so that light from the sun doesn’t enter the telescope (this would damage its sensors). Not all of these orientations are good for looking for exoplanets however and so Kepler has been put to other uses. Several of the viewing periods have been dedicated to looking at planets within our own solar system, giving us insights into their behaviour like we didn’t have before. It recently spent 70 days observing the weather on Neptune and the motion of its moons, the longest observation of the planet to date. Additionally another observation period is being dedicated to doing a similar investigation on Uranus.
Like I’ve said before second chances with space missions are rare and it’s incredibly heartening to see Kepler producing these kinds of results 2 years after its reaction wheels failed. Whilst these might not be the exact results we’re after they’re still invaluable pieces of data that will help broaden our understanding of both our universe and galactic backyard. I’m sure that we’ll continue to see great things from Kepler and, hopefully, many more exoplanets.
Your garden variety telescope is usually what’s called a refracting telescope, one that uses a series of lenses to enlarge far away objects for your viewing pleasure. For backyard astronomy they work quite well, often providing a great view of our nearby celestial objects, however for scientific observations they’re usually not as desirable. Instead most large scientific telescopes use what’s called a reflecting telescope which utilizes a large mirror which then reflects the image onto a sensor for capture. The larger the mirror the bigger and more detailed picture you can capture, however bigger mirrors come with their own challenges especially when you want to launch them into space. Thus researchers are always looking for novel ways to create a mirror and one potential avenue that NASA is pursuing is, put simply, a little fabulous.
One method that many large telescopes use to get around the problem of creating huge mirrors is to use numerous smaller ones. This does introduce some additional complexity, like needing to make sure all the mirrors align properly to produce a coherent image on the sensor, however that does come with some added benefits like being able to eliminate distortions created by the atmosphere. NASA’s new idea takes this to an extreme, replacing the mirror with a cloud of glitter-like particles held in place with lasers. Each of those particles then acts like a tiny mirror, much like their larger counterparts . Then, on the sensor side, software is being developed to turn the resulting kaleidoscope of colours back into a coherent image.
Compared to traditional mirrors on telescopes, especially space based ones like the Hubble, this has the potential to both significantly reduce weight whilst at the same time dramatically increasing the size of the mirror we can use. The bigger the mirror the more light that can be captured and analysed and a mirror designed with this cloud of particles could be many times greater than its current counterparts. The current test apparatus (shown above) uses a traditional lens covered in glitter which was used to validate the concept by using 2 simulated “stars” that shone through it. Whilst the current incarnation used multiple exposures and a lot of image processing to create the final image it does show that the concept could work however it requires much more investigation before it can be used for observations.
A potential mission to verify the technology in space would use a small satellite with a prototype cloud, no bigger than a bottle cap in size. This would be primarily aimed at verifying that the cloud could be deployed and manipulated in space as designed and, if that proved successful then they could move on to capturing images. Whilst there doesn’t appear to be a strict timeline for that yet this concept, called Orbiting Rainbows, is part of the NASA Innovative Advanced Concepts program and so research on the idea will likely continue for some time to come. Whether it will result in an actual telescope however is anyone’s guess but such technology does show incredible promise.
When you think of scientific telescopes there’s usually only 2 different types that come to mind. The ones down here on terra firma, with their giant white domes covering their precious mirrors, and the ones up in space like the venerable Hubble Space Telescope. Each of these has is set of benefits and drawbacks, like the ground based ones having massive mirrors and the space based ones not having to deal with our atmosphere. However there’s potential for a telescope that straddles the boundaries of these two types of telescopes, one that’s far above the Earth’s surface but also doesn’t require the heavy energy investment of an orbital craft. Indeed NASA has flown craft like these in the past and they’re now looking to airships to fly the next generation of such telescopes.
Ground based telescopes suffer from 2 major drawbacks related to the atmosphere. The first is the aberrations caused by the shifting atmosphere, the same thing that causes the stars to twinkle at night, which makes precise measurements incredibly difficult. The second is that the atmosphere is great at absorbing a lot of the frequencies of light, specifically infrared, something which we can’t really overcome with special optics or filters. Putting a telescope in space negates these problems but brings with it a whole other set of challenges which is precisely why NASA is looking to develop a sub-orbital telescope concept using an airship as the platform.
NASA has constructed platforms like this in the past, the most notable one of which is SOFIA, an infrared observatory that’s built into the back of a Boeing 747. At its cruising altitude it’s able to see 85% of the total infrared light coming to Earth a considerable amount more than any ground based telescope will be able to see. The primary limit to SOFIA is its endurance time which is around eight hours or so although its capability to be pretty much anywhere in the world does make it incredibly flexible in the operations it can perform. The airship design that NASA is looking to pursue would address this limitation whilst providing some other benefits.
Airships, whilst not being as mobile as their winged cousins, have the advantage of being able to stay aloft in a location for extended periods of time that aircraft simply aren’t capable of doing. For an observatory this provides several advantages such as being able to do longer exposures on targets as well as being able to take advantage of higher bandwidth downlinks to their base sites. There are several engineering challenges that will need to be solved before a viable aircraft will materialize, but it’s certainly within the realms of possibility.
Pending funding of the idea NASA will be funding it X-prize style, looking for designs (and I assume workable craft) that can carry a small or large payload up into the atmosphere. Such programs have proved to be highly successful in the past and I’m sure we’ll see some pretty interesting craft come out of it. Considering that SOFIA is slated to be shut down due to budgetary concerns sometime next year a viable alternative needs to be sought so they don’t introduce more holes in their capabilities. Of course getting an airship with a telescope up in the air before that happens isn’t going to be likely but the sooner the process is started the better.
There’s no denying the fact that space based telescopes are by far the best instruments for us to observe the universe. They don’t suffer from atmospheric interference, observe targets for incredibly long periods of time and aren’t limited to observing a section of the sky. Of course they come with quite a lot of drawbacks as well often being incredibly expensive to build, launch and operate and unless you’re the Hubble you can forget ever being serviced or repaired, you’re more likely to be ditched in the pacific while your replacement is launched. Still it’s not like ground telescopes are useless by comparison and in the not too distant future our most powerful telescope might just be one located here on terra firma.
That, my friends is a rendering of the European Extremely Large Telescope (E-ELT) an upcoming ground telescope that has just received approval from the European Southern Observatory organisation to go ahead. The tiny car at the bottom of the picture gives you some clue into just how large this particular telescope will be, dwarfing nearly all those that have come before it. House inside that giant building is primary mirror array that is some 39.3 meters across, about half the length of a football field. To put this in perspective Hubble’s main mirror is about 8 meters across or almost 5 times smaller than that of the E-ELT.
Ah, I hear you say, but what about the fact that this one isn’t in space but Hubble is? Well traditionally that was quite a problem for telescopes as there wasn’t a good way to compensate for the changes in the atmosphere leading to blurred or low resolution images. There’s a couple ways to combat this and the usual method was to locate the telescope in a place that had favorable conditions for night time observations. This is usually in high up places so the amount of atmosphere is decreased but places like the Atacama desert, known as the driest place on earth, also provide excellent viewing opportunities almost all year round (320 out of 365 days are cloud free). There’s also a much more advanced way of dealing with atmospheric disturbances and that’s called adaptive optics.
Whilst I referred to the E-ELT as having a 39.3m mirror it is in fact more accurate to say it has a mirror array consisting of 800 individual elements that are all about 1m across. Each of these mirrors can be adjusted independently to compensate for any changes in the above atmosphere. They do this by using a laser to illuminate the sky above them providing a kind of artificial star with a controllable brightness that they can use to adjust the mirror array. Additionally the telescope has a secondary focusing mirror that has over 6000 actuators able to make adjustments 1000 times per second. Combining all of this together means that the E-ELT will have imaging capabilities far surpassing that of any telescope previously and will be the first telescope able to directly image rocky planets like our own orbiting other stars.
It’s that simple fact which has got me so excited about this new telescope. We’ve been able to directly image some planets around other stars in the past but we haven’t been able to get much detail out of them past a bright blob on a black background. The E-ELT will be able to resolve objects with astonishing levels of detail and I’m sure that our hunt for planets like our own will receive a massive boost at the hands of its giant mirror array. It’s projects like this, real envelope pushers, that keep me so excited about the wide vastness of space and how much of it we still have to explore.
The Hubble Space Telescope stands with the Shuttle as one of the most iconic space craft of the past 2 decades. It has been an amazing boon to science giving us images into the far reaches of space, revealing much about the universe that we would not have known without it. For all it has given us however it is starting to show its age after being in space for a continuous 22 years and the last decade has been dedicated to building a successor. Currently the craft lined up to replace it is the James Webb Space Telescope and whilst its a worthy replacement it’s nothing like the Hubble, for better and for worse.
You see Hubble really is a fully fledged observatory in space being able to capture several different wavelengths of light. This is why we’re able to get those gorgeous pictures out of it as the light it sees is pretty close to what our eyes can see. It’s not exact though as the various filters used to create the images are more aligned to detecting distinct spectral emissions so we end up with images made in what’s called the Hubble Palette. The JWST on the other hand is a pure infrared telescope which is great for studying distant and faint objects but is incapable of producing anything like the Hubble does. To really replace Hubble we’d need a telescope, or maybe even a couple specialized ones working in tandem, that covered a similar array of spectra.
Turns out the National Reconnaissance Office had a couple of these spare.
It might come as a bit of a surprise that the US Department of Defense (of which the NRO is a child agency) has a space program that rivals that of NASA in terms of scale and budget, but it has been that way for some time now. Of course their objectives are decidedly different with NASA being focused on science and exploration and the DoD more interested in the intelligence gathering prospects. It seems that as part of their spy satellite programs they have produced 2 telescopes with Hubble like capabilities that they no longer require (they have not been launched and returned as we have had no missions capable of performing such a task) and have gifted them to NASA. The question now is what to do with these 2 potential Hubble replacements, lest the gift be wasted.
Now these things aren’t exactly ready to fly satellites, they’re basically skeletons ready to be molded into whatever shape NASA wants them to be in. So the basics are there like the housing and the primary (and secondary, something Hubble didn’t have) mirror array but it’s missing crucial parts like the sensors, communication systems and I’m guessing stationkeeping equipment. So there’s a large parcel of work that’s already been done, and no doubt anyone who was looking to build a satellite would love to have this much done for them for free, but to actually get these things flight ready will take quite some time and, most importantly, some budget. If the required funds were found immediately NASA believes they’d be ready to launch no earlier than 2020, or a turnaround time of about 8 years.
Personally I believe that we’d be best served by configuring both telescopes to be identical and then launch them as a stereoscopic pair that could perform in space interferometry. This would allow us to surpass the capabilities of Hubble significantly and would open up imaging opportunities that just weren’t available otherwise. Of course we’d probably be better suited designing a whole new telescope with an even larger mirror array than the two combined but with NASA struggling to complete the JWST on time I can’t see that happening for anytime in the near future. Using these two proto-Hubbles would be an excellent solution for the interim however.
It’s not often that some like this happens so it will be very interesting to see what NASA does with these skeleton telescopes. I would love to see a visible spectrum telescope up there to replace the Hubble after it returns to Earth in a fiery blaze of glory but there are just as many other worthwhile goals for these little beauties. Whatever their fate I’m glad that they’re now in the hands of NASA as they’ll do a lot more good for mankind as science vessels than they ever would as spies.
I’ve long heard tales of how profitable asteroid mining could be. This is because asteroids, unlike Earth, tend to have higher concentrations of rare minerals with some even being almost entirely metallic, in essence taking out all the hard work of digging it up out of the ground. However actually mining asteroids or other heavenly bodies is a devastatingly expensive exercise as you have to haul all your equipment up there, conduct the mining operation, and then safely get the minerals back to Earth. Nothing along the way is trivial and whilst there’s been a great number of advancements making the trip there and back easier no one has yet tried to tackle the problem of mining in space.
However news has started circulating of a new company that’s setting its sights on just such a lofty goal and its name is Planetary Resources.
Now any company with such a lofty goal would attract some attention from the press but Planetary Resources is doing so for additional reasons: the people who are backing this project. We can count amongst them people like Tom Jones (a former NASA astronaut), Larry Page and Eric Schmidt (Google co-founders) and none other than James Cameron himself. The list seems to go on and it’s clear that this company must have some concrete plans to actually achieve their vision in order to attract such talent and some of those plans have just come to light.
Planetary Resources has already done some of the groundwork required in order for their business model to work. They’ve set their sites initially on Near Earth Asteroids of which there are about 8,840 known (although more are discovered every year). Of those known objects approximately 150 of them are thought to be water rich and require less energy to reach than going to the moon. They are then going to launch a high powered space telescoped designed to prospect these asteroids from afar within the next 2 years. It is likely that they will attempt to find the largest of these asteroids that are close enough together, allowing one launch to reach multiple asteroids.
Part of Planetary Resources goal is to make accessing such asteroids cheaper and this will be accomplished by establishing orbital refuelling stations on the way to those near earth objects. I’ve written in the past how these kinds of stations are required if we want to be serious about exploring and establishing a human presence beyond that of our current planet and it thrills me to see a company making this idea a reality. Such stations will not only make their activities much more economically feasible it will also allow agencies like NASA to be far more ambitious with their future projects, something which they’ve been lacking of late.
Details beyond that however are somewhat scant. Planetary Resources has declined to say when they’ll be breaking ground on an asteroid so the only solid timeline we have from them is that they’ll launch a telescope in under 2 years. Whilst there’s been some research showing that a mission could potentially be done by 2025 that was entirely theoretical and put the cost somewhere north of $2 billion. Now that’s not out of reach of Planetary Resources, several of their backers have fortunes that amount to several times that, but there’s no indication that they’ll be able to meet that schedule. I’m hopeful that they’ll be able to reach their goal eventually but until we start to see some real progress from them it’s best to not speculate too heavily.
Regardless of my apparent scepticism I’m still very excited by this announcement. We’re starting to see the combined efforts of many disparate companies beginning to create a snowball effect, one that’s creating a flourishing private space industry that was only recently a science fiction fantasy. We are so incredibly lucky to be living in a time that’s akin to the aviation revolution of the last century. I’m a fervent believer that within our lifetimes we’ll see commodity level space travel and I cannot wait to be a passenger.
Staring up at the night sky is one of the most humbling experiences I’ve ever felt. Each of those tiny points of light is a sun burning furiously in a runaway fusion reaction. By comparison I, a mere human, am no more than a tiny fleck in comparison to one of those stars and barely even an atom when compared to the teaming masses of stars that make up that beautiful nightscape. Even more daunting then is the possibility that each of those twinkling stars plays host to a solar system like our own with dozens of planets just waiting for discovery. Our hunt for these planets has brought us hundreds of large gas giants who by the nature have been very easy to detect. Direct imaging of these planets has been nigh on impossible with the precious few we’ve managed to glimpse being extraordinary examples, rather than the rule. That is set to change, however.
Light, you see, is a funny thing. For centuries scientists pondered over the modelling of it, with the two dominant theories describing it as either as a particle or a wave phenomena. Problem is that light didn’t fit neatly into either of the models, requiring complex modelling in order to fit its behaviour into either the particle or wave category. Today many of the properties of light are now explained thanks to Einstein’s theory of wave-particle duality but for a long time one of the most confounding properties of light was that light can interfere with itself. You’ve probably seen this demonstrated to you back in college via the double slit experiment where you get a pattern of light and dark from a single source of light. At the time I didn’t think much of it past the initial intrigue but my discovery of my passion for space many years later had me thinking about how this might be used.
I had been reading about the hundreds of exoplanet discoveries for a while when I heard of 2M1207b which is thought to be the first directly imaged planet outside our solar system. It’s an exceptional planet being an extremely hot gas giant orbiting a very dim companion star. For systems like our own there would be no chance of seeing any planets from the outside thanks to our extremely bright sun and our relative proximity to it. Still knowing that light had the novel ability to cancel itself out I had wondered if we could say build an apparatus that forced light from a parent star to cancel itself out, letting us peer behind the blazing might to see what lie beneath.
It wasn’t until a few years later when I stumbled across the idea of a StarShade which had been proposed many years previously. In essence it would function as an augmentation to any space based telescope positioning itself perfectly in front of the parent star and reducing its brightness by a whopping 10 billion times. In comparison then the tiny planets which were once outshone would glow bright enough for the telescopes to be able to see them directly, hopefully leading to direct detection of many planets orbiting the star. Unfortunately it appears that this project is now defunct but that doesn’t mean the idea doesn’t live on in other forms.
Most recently an international collaboration of scientists developed a Apodizing Phase Plate coronagraph which is in essence a scaled down version of a starshade that can be installed in current telescopes:
Installed on the European Southern Observatory’s Very Large Telescope, or VLT, atop Paranal Mountain in Chile, the new technology enabled an international team of astronomers to confirm the existence and orbital movement of Beta Pictoris b, a planet about seven to 10 times the mass of Jupiter, around its parent star, Beta Pictoris, 63 light years away.
At the core of the system is a small piece of glass with a highly complex pattern inscribed into its surface. Called an Apodizing Phase Plate, or APP, the device blocks out the starlight in a very defined way, allowing planets to show up in the image whose signals were previously drowned out by the star’s glare.
It’s not just planets that this device helps discover either, it can also help detect distant objects that are hidden behind brighter ones. This enables telescopes to become even more powerful than they once were with minimal modifications. Probably the best part about this is that they’re already using them on the Very Large Telescope in Chile, proving that technology is much more than just a theory.
There’s so much to discover in our universe and it always gets me excited to see these pieces of technology that allow us to pull back the veil and peer ever further into the deepest parts of space. It’s so humbling to know that you’re just a tiny piece of a seemingly infinite universe yet it’s so enthralling that I lose myself for hours just staring up at the night sky. I feel so privileged to be living in a time were our knowledge of this universe is increasing at an ever accelerating rate yet we’re still left wondering at the awesome beauty that’s put before us.
A few months ago I blogged about an amazing shuttle mission that set off to perform maintenance on one of the most important pieces of scientific equipment for humanity, the Hubble Space Telescope. Up until now the Hubble team has been performing calibration tests and making sure that everything is working properly after its last trip into space. Well now the time has come for them to release the images that they’ve acquired over the past few months, and I must say they are stunning.
Before you gallivant off and ogle the 56 pictures NASA has released to us I want to show you something that really drove home just how important the Hubble is. First off let’s have a look at a ground based observation of Stephan’s Quintet, a cluster of 5 galaxies who are very close together and have been very well studied over the past decade:
That picture was taken from the Kitt Peak National Observatory using a 2.1 meter telescope back in 1998. Whilst its not the most amazing picture it does give away some detail about the galaxies and their relationships with each other. For instance the one in the bottom left hand corner (NGC7320) looks very blue in relation to the others. This is due to a process called redshift where as light travels towards the observer it stretches to the lower energy (red) side of the spectrum. This would lead us to believe that NGC7320 is probably closer to us than its neighbours, although you can’t say that definitively with this picture.
Let’s step into the future 2 years from when this picture was taken and have a look at this beauty:
Well hello there gorgeous! The picture is basically a zoomed in version of the last one, but boy look at the detail! This really demonstrates the power of putting a telescope in space as the primary mirror on Hubble is only 2.4m big, a mere 30cms more than the previous picture. We can now quite clearly see the redshift in 3 of the galaxies visible here, with NGC7320 hiding off in the corner. This was even before its last camera upgrade in 2002 with the Advanced Camera for Surveys. 7 years later NASA gave Hubble its last upgrade and it seems that it was money very well spent.
Oh dear, could you all give me 5 minutes alone with this picture? 😉
But seriously just….look…at….that! The detail is phenomenal and even with these galaxies being so far away (most are above 200 million light years away) we can still pick out individual stars. The Hubble team has also kindly added some information to this picture and you can probably guess what my earlier ramblings have been leading up to. The numbers on the respective galaxies are the amount of redshift the light has undergone before it has reached us. Looking at NGC7320 we can see it is significantly lower than the rest, which means it is actually a lot closer to us at about 39 million light years. There’s also another clue as to why NGC7320 is close to us, can you guess what it is?
Have a gander at NGC7318A/B and NGC7319, aren’t they a little unusual? For starters NGC7318A/B are two galaxies in the last stages of merging. You can see some of the starts and other stellar material being thrown off towards the right side of the picture. NGC7319’s lower spiral arm is significantly distorted towards NGC7318A/B, showing that their combined masses are pulling them in. But what of NGC7320? It looks like your normal galaxy and that’s because it’s so far away from the other three that their gravity has little effect. There’s so much that this one picture shows us!
It’s things like this that really inspire me. In just a little over 10 years we’ve gone from a fuzzy picture of distance galaxies we can make guesses on to something like this which shows amazingly distance objects in spectacular detail. We still have another 5 years before the next space telescope takes off and it looks like Hubble will be doing a fantastic job until it comes online.
Now I just need to convince NASA to bring Hubble back to earth, as was their original intention.