Posts Tagged‘capture’

NASA’s Ambitious Asteroid Capture Mission.

Whilst the debate among the space enthusiast community still rages about what the next target for human exploration should be those with the capability seem to have already made a decision: we’re going to Mars. NASA has committed to getting astronauts there some time around 2030 and SpaceX’s founder and CEO, Elon Musk, has long held the dream that he’d be retiring on Mars. There’s also the Mars One which, to my surprise, is still going and garnering attention worldwide even here in my home country. The lack of a return mission to the Moon does raise some questions about the technology that will be used as we don’t have any craft capable of going past low earth orbit, not since the Apollo program ended almost half a century ago.

Orion_with_ATV_SMNASA has been working on a new crew capsule for some time now, dubbed the Orion. Initially this was part of the planned 2020 mission to return to the Moon however the majority of that was scrapped in favour of going directly to Mars. The capsule and the revised launch system were retained however and will form the basis of NASA’s future manned space missions. However if the Moon is no longer the goal for this craft and it’s end goal will be long duration flight there’s a lot of testing that needs to be done before we send one of them to Mars. Interestingly NASA has gone for an incredibly ambitious mission to put the Orion’s long duration flight capabilities to the test: an asteroid capture and analysis mission.

There’s currently two mission profiles being considered, both of them seeming like something straight out of science fiction. The first (and I’ll guess least likely of the two) is a robotic craft will make its way to a large asteroid, break a chunk of it off and then bring it back into orbit around the moon. The second would be a straight up asteroid capture with the craft grabbing an asteroid in its entirety (it would be small, about 7m or so in diameter) and, again, putting it into lunar orbit. Then once the asteroid is in a stable orbit NASA will send crew to it in an Orion capsule to study it, testing out some of the long duration capabilities as well as other rudimentary space activities like EVAs.

Such a mission is actually quite feasible (at least the latter profile) from a technical perspective. Pretty much all the technology required to capture an asteroid of that size is available today and there’s already 6 candidate asteroids identified. The main issue I see with it is time as just getting to the asteroid is planned to take at least 4 years with another 2 to 6 required for it to make the trip back. That means if the mission were to launch today it could potentially take up to 2024 before it returns to us which doesn’t leave a lot of time for NASA to test out the Orion capsule on it, This could be sped up considerably by changing it’s launch profile to include a second stage rocket to boost it rather than relying on the ion thrusters to achieve escape velocity but that would come with additional expense. There’s also the possibility of foregoing the robotic part of this mission completely and just sending humans although that poses just as many challenges as going straight to mars.

I’m glad to see NASA making a return to missions like these, ones that truly push the envelop of humanity’s space capabilities. It’s going to be interesting to see how the mission develops as there’s lots of different variables that need to be sorted out, some that will change the mission dramatically. Still the thought of us being able to capture an asteroid, bring it into lunar orbit and then send humans to study it is just an incredible thing to think about and I truly hope NASA sees this one through to fruition.

 

Watching Photons Fly.

You can see light’s presence everywhere, but have you ever seen it moving? Due to the speed of light being the fastest thing we currently know of it’s a rather elusive beast to see in motion, especially on the scale we exist in, and whilst it might look instantaneous it does have a finite speed. Whilst we’ve done many experiments in slowing light down and even trapping it for short periods of time but being able to watch a light ray propagate was out of our reach for quite some time, that was until the recent development of a couple technologies.

The above video is the work of Ramesh Raskar and his team at MIT which produced a camera that’s capable of capturing 1 trillion frames per second. However it’s not a camera in the traditional sense as the way it captures images is really unique, not at all like your traditional camera. Most cameras these days are CCD based and capture an image of the whole scene then read it off line by line and store it for later viewing. The MIT system makes use of a streak camera which is only capable of capturing a line a single pixel high, essentially producing a one dimensional image. The trick here is that they’re taking a picture of a static scene and doing it multiple times over, repositioning the capture area each time in order to build up an image of the scene. As you can imagine this takes a considerable amount of time and whilst there are some incredible images/movies created as a result the conditions and equipment required to do so aren’t exactly commodity.

There are alternatives however as some intrepid hackers have demonstrated.

Instead of using the extremely expensive streak camera and titanium sapphire laser their system instead utilizes a time of flight camera coupled with a modulated light source. From reading their SIGGRAPH submission it appears that their system captures an image of the whole scene and so to create the light flight movies they change when the light source fires and when the camera takes the picture. This process allows them to capture a movie much quicker than MIT’s solution and with hardware that is a fraction of the cost. The resolution of the system appears to be lower, I.E I can’t make out light wave propagation like you can in the MIT video, but for a solution that’s less than 1% of the cost I can’t say I fault them.

Their paper also states they’re being somewhat cautious with their hardware, running it at only 1% of its duty cycle currently. The reason for this is a lack of active cooling on their key components and they didn’t want to stress them too much. With the addition of some active cooling, which could be done for a very small cost, they believe they could significantly ramp up the duty cycle, dropping the capture time down to a couple seconds. That’s really impressive and I’m sure there’s even more optimizations that could be made to improve the other aspects of their system.

It’s one thing to see a major scientific breakthrough come from a major research lab but it’s incredible to see the same experiments reproduced for a fraction of the cost by others. Whilst this won’t be leading to anything for the general public anytime soon it does open up paths for some really intriguing research, especially when the cost can be brought down to such a low level. It’s things like this that keep me so interested and excited about all the research that’s being done around the world and what the future holds for us all.