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.
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.
This morning, at 4:01am Australian Eastern Standard time the Shuttle Mission STS-125 blasted off on what is to be the last visit a human will ever make to the space telescope, Hubble. I’ll admit watching the lift off today left me a little teary eyed, as have many launches before. There’s one person though who I’m sure will be far more eager to see Hubble again then anyone else, astronaut Mike Massimino:
“I do actually get a chance to touch the Hubble and I can hug it when I get up there,” Massimino told SPACE.com in a phone interview. “Yeah, the Hubble is great.”
Massimino and the other members of the shuttle Atlantis’s STS-125 crew, led by commander Scott Altman, are due to lift off May 12. The astronauts plan an 11-day mission packed with five spacewalks to repair hardware and install equipment such as a new camera, gyroscopes and batteries. The upgrades should extend the observatory’s lifespan through at least 2013.
For Massimino, revisiting the telescope will be a trip down memory lane.
“I’m really looking forward to seeing Hubble again,” he said. “I saw it seven years ago. I think it’s going to be really cool and I think it’s going to bring back a lot of memories, and remind me of emotions I had during the last flight that I forgot about or haven’t thought about in a long time.”
Reading this article last month really brought this mission home for me. Just imagining going up there once and seeing this impressive telescope back dropped by our beautiful blue marble of a planet would be enough for anyone. Going up a second time would be like going home to visit your old friends, something sure to stir the emotions and tug at the heart strings. Truly the astronauts on this mission are some of the most fortunate people, and I wish them as safe journey.
Hubble is about to receive 7 astronauts who will perform an intensive 11 day mission. This mission includes 5 intensive 6.5 hour back to back space walks as well as the routine of ensuring that the shuttle is capable of landing back on earth without incident. This is a routine procedure since the Columbia disaster back in 2003 and is the cause for one of the most amazing plans that NASA has put into place.
Current NASA policy dictates that should the shuttle suffer significant damage before it returns to earth, either by debris or otherwise, it must have a safe haven that it can go to whilst a rescue mission is prepared using another shuttle. Since the typical Shuttle mission is to the International Space Station this usually isn’t a problem, as the station can cater with the extended load for a moderate amount of time. Worst comes to worst they can always shuffle 3 of them off in the Soyuz life boat in order to reduce the load. Due to the high orbit required to get to Hubble (559KM above earth, the ISS is only 347KM) and the different orbital inclination (28.5 to 51.6 degrees) the energy required to perform such a manoeuvre, called a plane or orbtial inclination change, is extremely prohibitive. Therefore, they have a backup plan unlike anywhere else:
Should Atlantis not be able to safely return to earth Endeavour will be launched in order to rescue them. The mission itself is no small feat either, with a tricky set of manevours planned in order to get all the astronauts across safely. Whilst I don’t wish any harm on the astronauts I’d love to see this plan put into action, as it would be a testament to NASA’s prowess when it comes to operating in space.
Whilst this mission doesn’t have as much of a human element as trips to the ISS do it does hit close to home. Once this mission is over the astronauts up there will be the last to see Hubble in the flesh and I’m sure the departure will be a bitter-sweet moment for them, as it will for the rest of us.
Launch photo credit: NASA/Fletcher Hildreth, May 11, 2009
Twin shuttle photo credit: Robert Pearlman/collectSPACE.com