Category Archives: Space

How Do You Find a Planet?

Recently, scientists have announced the potential existence of another planet in our solar system out past Pluto. If true, this would bring our planet count back up to nine, after the demotion of Pluto to a dwarf planet. Planet 9 is theorized to be a gas giant, larger than Earth, exist out in the Kuiper belt, and have a very long orbit around the sun, some 200 years. This is a very cool discovery, but how do you find a planet in the solar system? You’d think they’d all be found by now.

Well, the scientists first got hint of a large planet out in the Kuiper belt by observing the dwarf planet Sedna which is in the belt. Sedna was found in 2013 and the scientists noticed it’s orbit was odd. But what does “odd” mean exactly? First lets talk about gravity and orbital motion. In space, gravity is the primary force that drives the motion of planets, stars, and asteroids. In the simplest case, we can consider just two bodies, one large main body that is fixed and one smaller that orbits around the main body. For example the Sun and the Earth. This is called 2-body orbital motion. It assume that the main body is so much larger that we can neglect the mass and thus gravity of the smaller body. In 2-body motion, the smaller body follows a constant and nice elliptical orbit around the main body.

In reality though there are lot of bodies out there, and every object exerts gravity on every other object. Just in our solar system there are 8 large planets. So those planets are constantly tugging on each other even though the sun is the one controlling the main motion (which is why everything orbits the sun). Jupiter is the largest planet and it has a noticible effect on everything in the solar system. Jupiter may be partly responsible for the existance of the human species actually. Jupiter’s strong gravitational pull may have acted like a asteroid shield of sorts and altered the trajectory of space rocks that would have hit Earth in the early days of life on this planet. So the planets, and especially Jupiter cause the Earth’s orbit around the sun to be changed slowly over time. This is still happening today. But the changes are too small for us to notice, but we can measure the deviation from the 2-body orbit with scientific instruments.

The scientists noticed something similar with Sedna. After watching it and calculating its position over time, we can determine the orbit it follows. We can use computers to account for the perturbing effects of Jupiter and the other planets on Sedna. The asteroids and other objects in the Kuiper belt are all too small compared to the planets to have a significant effect on Sedna’s orbit. These days we’re pretty good at calculating orbits if we know all the major bodies involved. They can see where Sedna is at some later time to confirm that the calculated orbit is correct . Now what the scientists probably saw was that Sedna was not moving according to the calculated orbit, which means there’s a large body with a strong gravity that wasn’t accounted for. The deviation form the calculated orbit was probably very small, maybe a few kilometers, which in space is minuscule but enough to suggest there’s something else out there. So the scientists spend some time and ran more computer simulations using the measured position data of Sedna. They probably created many different bodies in the Kuiper belt and calculated their effect on Sednas orbit looking for one that would match the actual data. The result seems to be a large gas giant about 10 times bigger than Earth in a large egg-shaped orbit around the sun out past Pluto. Now comes the challenge of trying to find planet 9.

What will come next will likely be close examination of the scientist’s data to double check their work. If others agree, then they will likely take measurements of other objects in the Kuiper belt over time and see how the behave and if planet 9 could be responsible for any oddities. Finally, after watching enough Kuiper belt objects, we’ll have a good guess of where planet 9 could be. Then it becomes a game of cat a mouse as we turn all our telescopes towards a small patch of sky and try to find one plants in the blackness of space. It’ll be a long process since finding planets or stars requires a lot of data and you’re looking (or the computer is looking) for very small changes in light from one image to the next, on a pixel by pixel basis. But if we find it, it’s be the first planet since Pluto was found in 1930.


Bigger, Better, Faster, and…Cheaper?

My research is in plasma physics and propulsion with a focus on practical applications. To develop new technologies you have to push against the boundary of what is known, and that take times and usually happens in small incremental steps. In other words the new technology is only a little better than the current technology. For some things like computers and smartphones, a little better seems to sell, thus a new iphone every 6 months, even though they may not be a substantial improvement over the previous version. However in spacecrafts and propulsion, a little better isn’t good enough. The motto of propulsion has always been bigger, better, and faster engines. However in recent times an additional property has been added, cheaper. Now that seems to be at odds with the previous three. How do you get a bigger engine for less money?

Better and cheaper is usually an oxymoron for technology. To make something better, usually in performance, requires improvements in materials, science, coding, and so forth. All that of course takes time which costs money. Then if you have to use higher performance materials or components, those cost more money. Lets say you want a higher performance jet engine for airplanes. Maybe you run the engine faster or hotter to get more thrust. That requires higher strength materials to withstand the higher temperatures and stresses. If the engine runs faster, you may need more robust gears or shafts to transfer the force. Thus the engine is more expensive.

The exception to the rule where you can get cheaper and better, eventually, is when a paradigm shifting technology or process comes along. Computers are a prime example, or rather the production of computer chips. Computer used to run on vacuum tubes and punch cards and took and entire room. Then came the discovery of semi-conductor materials, transistors, and the methods to produce them. Now computers can fit on a desk. Now the technology to produce computer chips continues to advance to make smaller and smaller transistors. This allows you to put more and more transistors on a square inch of silicon. This not only allows you to increase the computer speed, but also means you can make lower performance chips using less material thus less money. Thus today the $100 tablet is much more powerful than the room sized computer of the 60’s.

So to get bigger, better, and cheaper you need a paradigm shifting new technology. In space and propulsion, those are harder to come by. We are currently push up against the theoretical limits of jet and rocket engines. There’s just not much more room to improve according to the laws of physics. So there’s not alot of impetus to develop new engines. New jet engines are still being developed not necessary for better performance, but to reduce emission and operating costs. Currently there is some rocket engine development occuring in the US. Aerojet and Orbital ATK are both spending their own money to develop a new liquid rocket engine, though it’s not going to be drastically better than the existing engines. The RS-25, better known as the Space Shuttle Main Engine, is the highest performaning rocket engine ever developed by humans. It is also horrendously complicated and expensive. The new engines are unlikely to try and meet or beat the SSME’s performance. So why is money being spent to develop a new engine that’s not going to better than the best we have? The answer is politics. The new engines are being developed to replace the Russian RD-180 which we currently buy from Russian to power the Delta and Atlas rockets. Given the recent tensions with Russia, Congress has decided giving money for rocket engines is bad. So this is a case of not better, not cheaper, but necessary due to non-technology issues.

In my mind, there are two contenters for paradigm shifting technology in propulsion: nuclear, and addition manufacturing (3D printing). Fusion propulsion has the potential to make interplanetary travel much faster and eventually cheaper. But the technology is still in its early stages and will be very expensive to develop. So fusion propulsion can satisfy the better desire. The cheaper part could be fullfillled by 3D printing. Additive manufacturing can greatly reduce the time and cost to produce components, which will make things cheaper. It also has the potential to make very complex components which may improve performance if designed correctly. Companies have already 3D printed small rocket engines or parts of rocket engines and shown the parts can survive the high temperatures and pressures. Initially 3D printed parts won’t have better performance than their conventional counterparts, and in some cases may have worse performance. But as the technology is further developed, 3D printed engines could also reach the better criteria.

Space Radiation and Human Exploration

Recently, scientists have shown that mice who had a high energy particle beam shot through their brains suffered some loss of curiosity and ability to do work. Now your response might be “well duh, you just shot the mice with a particle beam, of course it’ll have problems.” To most of us it’s just an interesting or slightly cruel science experiment. However to astronauts and the engineerings and scientists looking over them or trying to get them to Mars, it’s a serious concern.

Space is abound with radiation. Every time we send something up there, it will get hit by high energy radiation. We just design equipment to have redundancy and still be able to operate if one system goes down. However we can’t build redundancy into humans. Astronauts on the space station regularlly see flashes in their vision when they close their eyes to go to sleep. Those flashes are due to a high energy radiation particle striking the astronaut’s optic nerve. Luckily a few strikes don’t cause long term harm, as far as we know. Additionally, the space station is protected from the the majority of the harmful radiation by the Earth’s magnetic field, which also protects us here on the ground. But if we send people to Mars, they will spend a few months outside the Earth’s protective field and in direct exposure to whatever is out there. So engineers and scientists are trying to figure out ways to protect human during long space trips.

There are two types of radiation in space, Galactic Cosmic Rays (GCR) and Solar Particle Events (SPE). SPEs are generated by the Sun and consist mostly of electrons, hydrogen nuclei, and helium nuclei. The Sun throws out these particles as part of its regular nuclear fusion process. During solar flares, it gets really bad and becomes a high energy particle bombardment. GCRs are even higher energy particles of all elements up to iron. These particles are stripped of all their electrons and zoom through space at incredible speeds with hugh energy. GCRs comes from outside our solar system. Currently theory says GCRs are created by the destruction of stars and the resulting novas or supernovas that accelerate these particles to extremely high speeds. SUPERNOVAS! That’s pretty damn amazing I think.

So these particles can greatly threaten our future human presence in space outside of Earth’s orbit. Even if we go to the Moon, space radiation will still be a concern because the Moon doesn’t have much of a protective magnetic field. For a Moon base, an “easy” solution would be to build the based underground and let the Lunar dirt protect the astronauts. For space travel though, we can’t bring a huge pile of dirt. On Earth, nuclear reactors and waste are shielded with thick layers of lead, steel, and concrete. All of those materials are incredibly heavy, and not really feasibly to take with on a space trip. A spaceship would require a few inch thick layer of lead or steel, which would make the ship extremely heavy. An alternative is to use water as shielding material. In fact any material with a large amount of hydrogen is a good shielding material. Water is used on earth for nuclear reactors to both cool and shield the radioactive fuel rods. There was even a recent NASA study to examine the use of a water recycling bladder as the external hull of the spacecraft.

Massive spacecraft shielding may not be the only solution for the problem of radiation for travel to other planets. You see the primary problem is how long you spend in the unprotected regions of space between planets. So if you could greatly cut down on the travel time from say here to Mars, then you can get away with much less spacecraft shielding. So there is a trade between more shielding and more fuel for the engines. Now if we had much better engines that can do more with less fuel, that would be the best option. However the current high power engines are typically based on nuclear power, which has its own radiation and other issues. So what’s the answer? Right now with our current technology, most likely a compromise between existing propulsion systems carrying more fuel and a moderate amount of shielding. But there will undoubtedly be some exposure to space radiation, and I’m sure it’s something the astronauts, scientists, and doctors will be expecting and prepared for. Who knows though, one of the current mission concepts for NASA’s Space Launch System has a manned mission to Mars in the 2030-2045 time frame, and by then we may have discovered some brand new propulsion system or way to protect astronauts from radiation either with shielding or maybe a medical alternative that makes humans more resistant to radiation.

Catch-22 of Space Ventures

Recently, the Mars Society Convention had a debate between the Mars One co-founder Bas Lansdorp and two of the company’s critics from MIT. Gizmodo had a summary piece with some op-ed. I think the writer came off a bit mean, but I get where she’s coming from. To make sure we’re all on the same page, Mars One is a commercial startup venture that plans to send humans to Mars by 2024 and then every 2 years or so in order to build a colony. They’re probably most famous for their open call for astronaut and the subsequent down-selections that have been going one for a few years now. Now Mars One is a one-way trip, no returns. So these people are knowing volunteering to dedicate the rest of their lives to this mission. That has a certain amount of inspiration, though not everyone agrees. Last year, graduate students at MIT conducted a systems and feasibility analysis of the Mars One plan. Their findings say the astronauts will quickly perish on Mars, whether from starvation, dehydration, destruction of the habitat, break down of equipment, and various other grim scenarios. So as you can imagine, there’s some heated debate and antagonism between the company and the academics. This report is directly hurting the ability of Mars One to raise money to support the development of the necessary technology to prove their goal, which builds confidence and get more funding. And there’s the catch-22 for Mars One, or any commercial technology venture: they need money to develop the technology, but need the technology to build investor confidence so they’ll give money.

For any commercial entity who’s business is based on a product, whether it’s physical or digital, you need something to show potential investors in order to get their confidence. Investors are obviously looking for a return on investment, thus the name. They can invest in established products like toilet paper, but there’s probably very little gain to be had there. In the riskier markets like technology, the internet, and space, there is a greater potential for profit if the company succeeds. But they need to believe you will succeed, and not believe in a take-my-word-for-it manner, but in a data-backed-and-sound-business-strategy manner. That’s what’s currently hurting Mars One, the data is not going their way.

If we’re talking space ventures like Mars One, Planet Labs, Planetary Resources, Rocket Labs, Firefly, etc, then product or service is or requires some advanced technology, like a launch vehicle. Rockets and spacecrafts aren’t cheap. They’re probably one of the most expensive items you can buy that you don’t get to keep. Fancy houses and artwork go for hundreds of millions of dollars, but they get to be enjoyed for years. A rocket costing $50 million is used and lost in a day. And if the first rocket fails, that’s a lot of money down the drain, and no return on investment. So investors are logically wary of such a high risk venture. To help alleviate those fears, the company ideally wants to have the technology developed and tested, a clear plan for moving forward, an existing customer base, and knowledge of what’s the return on investment. But, real life is not so easy. Mars One is missing in all those categories. The necessary technology for in-situ resource utilization, habitats, food growth, and parts manufacturing on Mars are still a ways from being ready. They do have a plan forward, but it’s highly dependent on the technology. I don’t think there is a customer for the trip, since it is one way and they’re not bringing resources back. Thus I don’t know how investors would get a profit.

I don’t know if Mars One will fail or not. I don’t wish for them to fail, for they’re putting a goal out there. And difficult goals is what drives innovation and civilization. But theirs is a cautionary tale for other aerospace startups, especially in the commercial space business. To get funding, you have to demonstrate capability and a high probability of success. Before asking for money, develop the technology, at least part way, to show the potential you have. Of course you need money to do the development. Chicken and the egg problem all over again. The solution? I don’t really know. The best I can come up with is government funding as the government is not in the business of making money. So they can and do fund small enterprises to get them off the ground.

Sunset on Mars

NASA recently release a video of the sun set on Mars as seen by the Curiosity rover.
It’s more a set of time lapsed images as the rover doesn’t take full motion videos. The engineers color corrected the images since the rover’s camera is black and white only. However they know the spectral data of the light, so we know what the color is supposed to be. Thus we see what the actual colors would be of the Martian sunset. Turns out the sunset is blue-ish on Mars. This is caused by the presence of a lot of dust in the Martian atmosphere that scatter the light and makes blue come through instead of red. This is Rayleigh scattering, the same phenomenon that gives up blue skies and red sunsets, kind of the opposite of Mars actually.

Rayleigh scattering is the bouncing of light photons from atoms, molecules, and dust particles. When a photon hits a particle, it can bounce off the particle in a different direction. The wavelength of the deflected photon can change depending on the angle. On Earth, the photons bounce off mostly nitrogen. If the photons are deflected by around 90 degrees, then the light turns blue. If instead the photons are deflected straight forward, then the light turns red. So we have blue days and red sunsets. The Martian atmosphere is mostly CO2, which has different behaviors, thus the blue sunset.

Of all the images that have come back from Mars, these are one of the most inspiring and awe-inducing for me. The desert landscapes of Mars, the geological samples, the chemical data, and all the other data are very interesting scientifically. However they all seem so far removed from our everyday human experiences. But the sunset is something we have all seen many times. Songs, poems, and paintings have been made about the beauty of sunsets. It has romantic connotations. The fact the sun sets on Mars is a given, but it’s probably not a fact we’ve really thought about. It’s a piece, a tie, to our Earthly lives. One day, the first men and women to step foot on Mars will see the sunset and feel a bit more human and closer to home.

Consummerization of Aerospace Startups

This is a follow-up or continuation of the previous post on small satellites and turning them into an entertainment service. The idea is based on the fact there is a lot more money available in the consumer’s pockets than government or big business. Today, the government funds the majority of work by businesses or academics, especially in space related areas. Aeronautics (airplanes and the like) does have it’s own commercial sector from the airlines and transpiration. However even there the government spends money to support their military aircraft. Now I am not advocating for small government or anything political. In fact I believe the government has a key role to play in technology development. But I think we as a society and the aerospace field need to start thinking outside the box, and it will likely being with startups.

There was an article in 2013 back on whether startups will revitalize the aerospace industry. This would have been during the meteoric rise of SpaceX who now has a major stake in space launches. But even Elon Musk’s SpaceX is still a government contractor, serving primarily NASA and soon the military. Other startups like Planet Labs or Planetary Resources have move away from pure government support and their business cases seems to focus more on providing cheaper orbital observation or other services. But those services will still likely be bought and used heavily by the government or business, so still not consumer focused..

Consumerization is designing products and services focused on and marketed to individual consumers/end users. This is in contrast with produces and services focuses mainly for the business or government market. Space tourism is marketed to individuals while space cargo is marketed towards government.

The most successful startups are in the internet/software, small electronics, and medical devices sectors. On the internet side you have companies like Twitter, Minecraft, Instagram. In small electronics you can find examples in Pebble smart watch, Nest smart home thermostat. In medical devices there are small companies such as AdhereTech, Pixie Scientific, and even Fitbit. All of these startups have a product that directly serves and is bought by the individual consumer, your average Joe. And there are lot more Joes out there than government agencies. So if we take the same idea and apply it to aerospace, would it work? To consummerize anything, it needs to have two key factors: affordable, and appealing/useful.

Lets take the example of launch vehicles and satellites. Getting a rocket into space is dangerous, complex, and expensive. The cheapest rocket you can get today is likely the Minotaur 1 at about $40 million. There are a few small companies such as Firefly and Rocket Labs who are developing small launch vehicles to deliver single CubeSats. But even thre the launchs cost >$1 million. If those costs can be reduced to <$100k, then you’d be approaching the price range that’s affordable by private citizens, though very rich ones still. Some may say that’s crazy, and not possible, but consider the hobby rocketry community. Hobby rockets can reach altitudes of a few miles using simple solid motors for hundreds of dollars. So there is already a group of people who are interested in launching rockets and do it for a very reasonable price.

Now we come to the second question: appeal. The hobby rocket community is strong, but relatively small. They launch for the thrill and the challenge. Your average person spends their money mainly for thrills and fun, not so much to be challenged. So the biggest question that needs to be answered for the consummerization of aerospace is how do you sell it to the individual? What does the average person want? How do you make space fun? My instinct says the answer can be found by looking at sport (football, baseball, racing, etc), but I don’t quite see the solution yet. But it’s some food for thought.

We are made of star-stuff

The title is a quote from Carl Sagan’s famous book “Cosmos” which led to the original Cosmos TV show, which led to it’s recent incarnation with Neil deGrasse Tyson. I first read Cosmos one winter break when I was a graduate student. My wife had given it to me as a Christmas present. I very much enjoyed the book as it was a glimpse into history and the future. I like that quote so much it’s included in my Ph.D. dissertation. I feel that it perfectly encompasses the vastness of human life and its relation to the universe. But more on that later.

I recall commenting to my wife later that the book both uplifted and depressed me. The book was written in 1985, less than a decade after the Voyager probes left on their interstellar journey. The Galileo mission was still in the planning stages at the time. Dr. Sagan was thus writing from a time when these and other important space missions were just starting or being planned. He talked about the things these missions would accomplish and what we would learn about the universe. And he was right. It was uplifting to see all that we had accomplished today.

It was also depressing to see all that we had failed to accomplish from the visions of that time. Sagan envisioned a much expanded space exploration effort as well as a greater focus on science. He discussed missions that never occurred. He believed in the continued progress of science and the human drive to learn. But predicting the future is always a loosing game. I doubt at the time he could have predicted the turns and twists the US culture and politics have taken in the last 30 years. Science and space have been demonized as contributing to the degradation of society. Funding for space exploration is ever hard to come by these days. Fewer and fewer citizens are energized by the idea of exploring the universe. They see it as a waste of resources. My belief is that exploration is one of the greatest endeavors we can undertake as a species. It challenges our knowledge, industry, spirit, and ability to work with others. Space exploration brings out the best in people and teaches us more about our place in the universe and gives us tools to control our destiny. Now I think those are some great reason to support space exploration and meet Dr. Sagan’s vision.