Posts Tagged‘nuclear’

NASA Investigation Nuclear Propulsion for Future Mars Missions.

Moving things between planets is a costly exercise no matter which way you cut it. Whilst we’ve come up with some rather ingenious ideas for doing things efficiently, like gravity assists and ion thrusters, these things can only take us so far and the trade offs usually come in the form of extended duration. For our robotic probes this is a no brainer as machines are more than happy to while away the time in space whilst the fleshy counterparts do their bits back here on Earth. For sending humans (and larger payloads) however these trade offs are less than ideal, especially if you want to do round trips in a reasonable time frame. Thus we have always been on the quest to find better ways to sling ourselves around the universe and NASA has committed to investigating an idea which has been dormant for decades.

Orion_NTP

NASA has been charged with the task of getting humans to Mars by sometime in the 2030s, something which shouldn’t sound like an ambitious feat (but it is, thanks to the budget they’ve got to work with). There are several technical hurdles that need to be overcome before this can occur not least of which is developing a launch system which will be able to get them there in a relatively short timespan. Primarily this is a function of the resources required to keep astronauts alive and functioning in space for that length of time without the continual support of launches from home. Current chemical propulsion will get us there in about 6 months which, whilst feasible, still means that any mission to there would take over a year. One kind of propulsion that could cut that time down significantly is Nuclear Thermal which NASA has investigated in the past.

There are numerous types of Nuclear Thermal Propulsion (NTP) however the one that’s showing the most promise, in terms of feasibility and power output, is the Gas Core Reactor. Mostly this comes from the designs high specific impulse which allows it to generate an incredible amount of thrust from a small amount of propellant which would prove invaluable for decreasing mission duration. Such designs were previously explored as part of the NERVA program back in the 1970s however it was cancelled when the supporting mission to Mars was cancelled. However with another Mars mission back on the books NASA has begun investigating the technology again as part of the Nuclear Thermal Rocket Element Environmental Simulator (NTREES) at their Huntsville facility.

NTP systems likely wouldn’t be used for the initial launch instead they’d form part of the later stage to be used once the craft had made it to space. This negates many of the potential negative aspects like radioactive material being dispersed into the atmosphere and would allow for some concessions in the designs to increase efficiency. Several potential craft have been drafted (including the one pictured above) which use this idea to significantly reduce travel times between planets or, in the case of supply missions, dramatically increase their effective payload. Whether any of these will see the light of day is up to the researchers and mission planners at NASA but there are few competing designs that provide as many benefits as the nuclear options do.

It’s good to see NASA pursuing alternative ideas like this as they could one day become the key technology for humanity to spread its presence further into our universe. The decades of chemical based rocketry that we have behind us have been very fruitful but we’re fast approaching the limitations of that technology and we need to be looking further ahead if we want to further our ambitions. With NASA (and others) investigating this technology I’m confident we’ll see it soon.

The State of Warp Drive Science.

The biggest challenge we face when exploring space is the almost incomprehensible amount of travel we have to do just to get to other heavenly bodies to explore. The fastest craft we’ve ever launched, the New Horizons probe, will take approximately 9 years to reach Pluto and would still take tens of thousands of years to reach another star once it’s completed that initial mission. There are many ways of tackling this problem but even if we travel as fast as the fastest thing known (light) there are still parts of our galaxy that would take thousands of years to reach. Thus if we want to expand our reach beyond that of our cosmic backyard we must find solutions that allow us to travel faster than the speed of light. One such solution that every sci-fi fan will be familiar with is the warp drive.

Now many will be familiar with the concept, a kind of space engine that allows a craft to travel faster than the speed of light, however fewer will know that it actually has roots in sound science. Essentially whilst nothing can travel faster than light space itself can expand at a rate faster than light travels, a property we have already observed. The trick, of course, is being able to manipulate space in such a way that it shrinks in front of you and expands behind you, something which required a kind of exotic matter that, as of yet, has not been created nor observed. However if you watch the video above (and I highly recommend you do if you can spare the hour) you’ll see that there’s been some amazing progress in validating the science behind the warp drive model and it’s quite incredible.

For me the most amazing thing about the presentation was the use of a toroidal capacitor as a space warping device. The idea of a warp drive has long hinged on the idea that a new type of matter would be required in order to create the expanding and contracting regions of space. However White’s experiments are instead seeking to validate if a positive energy density field could create the required negative pressure zone, negating the need to actually create exotic matter. As he states in the video however the results are non-negative but not conclusive so we don’t know if they’re creating a warp field yet but further experimentation should show us one way or another. Of course I’m hoping for research in the positive direction as the other improvements White and his team made to the original Alcubierre designs (reducing the energy required to sustain the field) mean that this could have many practical applications.

The video also goes on to talk about Q-Thrusters or Quantum Vacuum Plasma Thrusters which I’ve written about here previously. What I didn’t know was just how well those thrusters scaled up with bigger power sources and if their models are anything to go by they could make many missions within our solar system very feasible, even for human exploration. Keen observers will note that a 2MW power supply that comes in at 20 tons is likely to be some kind of fissile reactor, something which we’re going to have to adopt if we want to use this technology effectively. Indeed this is something I’ve advocated for in the past (in my armchair mission to Europa) but it’s something that’s going to have to be overcome politically first before the technology will see any further progress.

Still this is all incredibly exciting stuff and I can’t wait to hear further on how these technologies develop.

An Armchair Scientist’s Mission To Europa.

If there’s any place in our solar system that we’d want to start seriously looking for life it’d be Europa. The dust covered snowball of a moon likely contains a vast subsurface ocean, one that is kept liquid by the giant gravitational forces of its host planet Jupiter. This makes Europa a great candidate for life as we know it as once we find water it’s inevitable that we find life shortly thereafter. The challenge with Europa though is getting to that subsurface ocean to study it as it could be covered in several kilometers of water ice, not something you can simply puncture through. Whilst there are numerous people more qualified than me on this subject, many of them actually working in the aerospace industry, with NASA asking for ideas for a potential mission to Europa I figured I’d throw my 2 cents in.

Europa

So the total budget for the potential mission is a cool $1 billion and whilst that sounds like a lot of money projects that I’d consider simpler than my idea (like say Curiosity which was $2.5 billion) but I think there’s potential to build a platform that could fuel further missions. With that in mind this initial mission is likely only to be a scouting mission, one that will give us the most detailed picture of Europa possible so that the follow up mission can choose the perfect site to land on and commence the search for life in its vast underground ocean. My proposal then is to develop a compact nuclear reactor (not a RTG) to power a scouting craft laden with instruments to analyse the gravitic field and surface of Europa. This craft will be able to find the point at which the surface ice is the thinnest and identify potential landing sites for the second generation craft: a cryobot that will punch through to the ocean below.

Putting a nuclear reactor into space might sound like the plan of a crazed sci-fi nerd but there’s actually been dozens of small prototype reactors launched into space with all of them proving to be safe and reliable. The power capabilities of such a reactor are far beyond that of what a small satellite would usually require however attempting to melt through kilometers of ice will require power of that scale. Thus it would make sense to fund research into developing the power supply first and then validating it on the scouting craft. Then, once that mission is successful, the reactor can be scaled to the appropriate dimensions for the cryobot mission and even used in other deep space programs.

Having such a generous amount of power available also opens up the opportunity to using instruments on the scouting craft which would not be feasible, typically. Things like high-power antennas (which could function as a relay for the follow up mission), radar imagers or bigger and better versions of other instruments. My knowledge on the power requirements of various instruments is limited but I know that even the most advanced RTGs, like the one in Curiosity, produce a measly 125W. Being able to draw on several kilowatts, an order of magnitude more power, seems like it would open up many opportunities that just weren’t possible previously.

I’m probably vastly underestimating how much it would cost to develop such technology, especially in today’s nuclear hostile political environment, but if we’re serious about actually digging under Europa’s surface I don’t see what our other options would be. Melting through giant sheets of ice is no small task and one that has requirements that far surpass anything we have currently. Using that $1 billion mission to set ourselves up for future exploration seems like the best bet especially considering how many other applications a safe, small nuclear reactor would have.

Obama Gone Nuclear With Power.

I’ve mentioned before that I’m a big supporter of nuclear (and renewable) sources of energy and how frustrated I am that the social stigma attached to it has seen what would otherwise be a clean and safe source of power slip by the wayside. Many people seem to think that there’s more danger inherit in this technology than there is in other power generation when this is simply not the case, but it seems that incidents of reactors past are still fresh in everyone’s mind. Still with countries like France pioneering the way for nuclear energy I’ve always held out that hope that one day we can transition away from our current energy dependency on oil and coal.

It would seem that Obama isn’t as short sighted as many of his constituents are:

In his speech, Mr. Obama portrayed the decision as part of a broad strategy to increase employment and the generation of clean power. But he also made clear that the move was a bid to gain Republican support for a broader energy bill.

“Those who have long advocated for nuclear power — including many Republicans — have to recognize that we will not achieve a big boost in nuclear capacity unless we also create a system of incentives to make clean energy profitable,” Mr. Obama said.

He also strikes on one of the biggest problems (other than the social stigma) that nuclear power faces: the cost. Current estimates for new reactors peg the total construction cost between $6~10 billion dollars with costs of construction going up faster than other means of power generation. Obama hits the nail on the head when he says that incentives are needed as the majority of western countries are quite hostile to new nuclear plants. The amount of regulation and beaucracy involved in setting up these plants typically makes them unprofitable for those who would want to set them up. Guaranteeing funding for the majority of the work means that a lot of the risk is absolved by the government, making the endeavour much more attractive.

Obama also gets kudos for using the proper spelling of nuclear (although that could be the reporter, I haven’t heard the speech myself. If you’ve got a link to it let me know!).

There is however hope for future reactors like the Westinghouse AP1000 (Yes, that Westinghouse) which has been commissioned by China for the princely sum of just $2 billion, a drastic reduction in cost. Additionally with China’s economy still growing strong they’ve planned a grand total of 100 of these reactors to be built over the course of the next decade which will have the added side effect of driving massive economies of scale when it comes to building AP1000 plants. With time I can see this reactor tech becoming a lot cheaper than their coal and oil counterparts, a critical step in driving mass adoption of nuclear technology.

However, whilst I believe that nuclear is the solution to many of our current problems I do not believe that it is the final solution to our insatiable craving for energy. Research shows that as GDP increases so does energy consumption, so you can imagine that a country like China who is just beginning to create a giant middle class will create a demand for energy on a scale that we haven’t seen before. Whilst nuclear will be capable of sustaining them (and others) in the short term the fact remains that nuclear is really just a far more efficient fossil fuel, and alternatives must be sought.

Currently my hopes remain in fusion technology. Whilst they still fall under the umbrella of fossil fuels they produce far and away more energy from orders of magnitude less fuel. However the technology is still in its infancy and requires significant amounts of research before commercial reactors become available. The good news is that many see the potential in this future technology with projects like ITER attracting funding and involvement on an international scale. People might say that fusion is always 20 years away, but I have my hopes for this technology.

Power in Space.

One thing that’s always a big issue for any project in space is how you’re going to power whatever you’re sending up there. As it turns out the methods that we use to generate power up in space are extremely varied and in fact many of them paved the way for technologies we now use back here on earth. However there are still some advances to be made and if we are to return to the moon and beyond there will have to be a breaking down of some old barriers in order to enable us to go further into space.

Many of the initial space craft that were sent up just had your traditional chemical batteries in them. For the most part these worked well, and since they had been around for such a long time they were a proven technology (something that is critical in any space endeavour). As time went on and missions became much more ambitious NASA moved from batteries to fuel cells and were the first to fly these in a space craft on their Gemini missions. Fuel cells are advantageous because not only do they produce power, but typically a decent amount of heat and water as well. In fact they are still used to power the space shuttle and will typically produce around 500 litres of water on whilst in space. This is invaluable as that’s 500Kg less water they have to bring with them and 500Kg more they can take into orbit.

Satellites are another matter entirely. Since they don’t need any of those bothersome human things like water and heat fuel cells aren’t the right choice for them and the majority of artificial satellites in orbit around earth and our nearby neighbours use good old fashioned solar power. At the distance we are from the sun the available power is somewhere in the order of 1400W/m² but that drops off dramatically as we reach further out into the solar system. In fact the amount of power available past mars is so little compared to where we are that there is only one mission currently scheduled to Jupiter that uses solar panels called Juno.

So what do we use when we want to explore the deep reaches of space? The current technology used in most missions is called a Radioisotope Thermoelectric Generator (RTG) which in essence uses heat from decaying radioactive material to provide heat and electricity. In the past they’ve coped a lot of flack for using these as environmental groups lament the potential for damaging the environment and spreading nuclear material across the earth. NASA has done extensive research on the matter but still runs up against endless red tape whenever they try to use one. The usefulness of these devices really can’t be overstated as they’ve given us such missions such as Voyager 1, which has been going strong for over 30 years and is slated to last for at least another 15. This kind of technology is going to form the basis of any mission that attempts to leave our solar system.

NASA has begun to make inroads into producing small nuclear reactors that would be used to power a moon base. For any kind of long duration time in space us humans need quite a lot more power than our robotic counterparts and we won’t be able to use RTGs to satisfy this requirement. Whilst I do understand some of the environmental concerns if I was going to trust anyone sending nuclear material into space it would be NASA, as they have a long track record of getting hazardous materials out of our atmosphere without incident. Unfortunately the environmentalists haven’t seen it that way, and continually put up roadblocks which inhibit progress.

Eventually though I’m sure we will be able to power our space based devices using nuclear power without the worry and red tape that we have now. As time goes by NASA and other space agencies will prove that the technology is sound after repeated launches and the controversy will be nothing but a memory. It is then we can start to look further out into our solar system, and hopefully, beyond.

It’s Pronounced “Nuclear”.

I can’t help but feel that there are some technologies out there that just get hit with a bad name once and are then driven underground because of it. Cold fusion was a great example of this since the scientists who were experimenting with it first didn’t follow proper scientific method but now any serious research into this area is immediately hit with disdain, even though there are some results that require further investigation. This becomes all the more painful when something that is proven to work gets the same sort of reaction. I am of course referring to nuclear power, or fission reactors.

Now what’s the first thing that comes to mind when someone mentions nuclear power to you? Is it a clean source of energy or do you get images of Chernobyl, Three Mile Island and nuclear weaponry? It seems the majority of the world is stuck in the latter mindset, only remembering the horrors that nuclear power brings to the world. The truth of the matter is that not only is nuclear power completely safe, it’s also a lot more friendly to the environment than any other fossil fuel based means of generating power.

The first round of questions I usually get concerning nuclear power is “Doesn’t it produce highly radioactive and toxic waste?” and the answer is yes, it does. However, per kilowatt of power produced a coal plant will release around 100 times more radiation into the surrounding environment. Additionally most of the waste produced by a nuclear plant that comes out radioactive means it’s still usable as fuel for a reactor, it just requires some more handling. This is done using breeder reactors which I do admit carry with them a small risk of proliferation. This can be easily offset by modifying the breeder to render the weapons grade stuff unusable, keeping the risk well within acceptable levels.

One country that has been listening to people like me is France, producing well over 85% of their electricity from nuclear sources. They’ve also only had 2 incidents arising from their use of nuclear power and breeding reactors, giving them an amazing track record for safety. You would think that if there was such a high risk in using nuclear power that the French would have had a multitude of accidents, but they haven’t. Clearly nuclear power is a lot safer than what the general public believes.

To give you an idea of just how bad public opinion is here’s a graph showing the number of nuclear reactors over time:

794px-Nuclear_Power_HistoryImage used under the The Creative Commons Attribution-NonCommercial-ShareAlike License Version 2.5 from Global Warming Art.

The Three Mile Island incident was a pretty minor affair technically and nuclear power continued to grow afterwards. However Chernobyl tarnished the world’s view of nuclear power and it hasn’t really recovered since. The fact of the matter is the reactor responsible for that disaster was known at the time to be an unsafe design and modern reactors are quite capable of shutting themselves down before such a disaster can occur.

It’s the old saying of once bitten, twice shy. The world suffered through a major accident with nuclear power and from then on anyone peddling it as the solution to the world’s energy problems has to work past lobbyists, politicians and the society at large. It’s hard to convince everyone that the risks are far lower than what they used to be, and for some reason the mythical idea of a clean coal power plant seems like a better idea than proven nuclear technologies. Australia as a nation, who’s uranium reserves are the largest in the world, is well positioned to take advantage of this technology. With so much unarable land available there’s no reason for us not to set up large reactors away from major population centres, keeping the “risks” to the population even smaller still.

So hopefully the next time you talk to someone about nuclear power you won’t see the green glowing boogey man that seems so ingrained in everyone’s heads. One day nuclear will be one of our few options left, and it is my hope that we begin working on implementing a nuclear based power infrastructure before its our last option.