Category Archives: Planetary Science

Year End Round-up

What is there to say? I’m here to vent my spleen at the science of the day.

  1. Elon Musk wants to put a man/woman on Mars. Well, we all want that. Can his ship land/take off again? Maybe. Looks like a good concept at least. Still, long way from here to trusting a rocket to set my butt down on the red planet. “Many a slip twixt the glass and the lip.”


2. Steven Hawkings wants to send sail satellites to other stars. The idea is terrible. I love his work, especially after he decided the Black Hole evaporation doesn’t happen. His current theory allows mini black holes, but enough about that. Let me trash his space probe idea.

Sorry, but just imagine that they do get the satellite up to 3000 km/s, a hundred times faster than anything we’ve done before. How far is a light year again? Look, 3 kklicks is a good number, it means you cross a light year in a hundred years. the CLOSEST target is about 3 ly away. So, the mission, launched in 2020, would arrive in 2320. Exciting, we’d get the return broadcast in 2323. Except, that is a boring dead system. The closest living world is about 10 light years away, so we’d get the broadcast in 3030. I ain’t waiting up. Besides, it’ll only be in that system for a few days. It’ll only be “near” the planet for about a minute.

Great, first principle of the light sail, it doesn’t have a breaking rocket. Not that you could slow down anything at that speed. We’re accelerating it using a super laser for a hundred years. Unless the aliens have a super laser, and want to slow down this beast, it isn’t stopping there, or anywhere. It will just keep going forever…buh bye.


3. NASA is getting a change in plan. It hasn’t had a plan in the last 8 years. Constellation, however you want to trash it, was a plan. It had some elements which may or may not have worked. I know, I was there, I worked on some of them. The radiation part, duh. I wrote, had my hands on at least, the majority of the environment documents. It was a plan. The Obama administration killed the plan. They didn’t have an alternate idea, didn’t really want NASA doing its thing. Whatever. Now hopefully a real plan for a Lunar Mission will be articulated. We’ll see.

4. I’ve got a paper to write. so I took a break to vent my spleen. Back to paper writing. I hope everyone has a good summer planned.

Fermi Paradox – Why can’t we see aliens?

I’ll try to find my Dragon Con presentation from 2014, but here is the question and short answer, for those interested.

Fermi Paradox: With all the stars in the galaxy, there is a high probability of aliens. Why can’t we see them and why don’t they visit?

The first part is simple. We can’t see much of the galaxy. Most of our view is out of the galaxy. If you want to think of our galaxy as rotating around a Z axis,+/- Z is our long view. It is only a few tens of light years. (Still a lot of stars) If you look toward the other directions, we are limited to around a thousand light years.


How big is 100 light years? Imagine that the galaxy is a queen sized bed. Scale runs around 600 light years per inch.

Try an experiment: Take a bunch of quarters and toss them randomly all over the bed. Each quarter is an active, visible, alien civilization. Nice, big pile near the center, maybe a stack by the headboard. A lot of those quarters are touching, right? Those civilizations can see each other.


Good, now put a quarter one foot toward the center from the lower left corner. Did you throw another quarter there? Well, apparently God didn’t either. The Fermi Paradox. There may be intelligent aliens out there, we just can’t see them.

As to why they don’t visit? Because space travel is hard. Star Wars is awesome, Star Trek is sufficient, but both break basic rules. Frankly, if those rules could be broken, they would have been. I expect that we’re always to be limited by light speed. Which basically means our top velocity is 0.1 C. We might plant a colony at 14 light years, but it is a several hundred year trip. The only aliens we’ll ever see with share our DNA.


NASA views

I guess the good news is that NASA is still funding JPL missions to the outer planets. I’m a bit disappointed in their engine selection, some of their mission choices, but overall, it looks like decent return on investment.

This is a view of Pluto. Nothing too exciting, really. There is a certain uniformity in the ice flows that looks artificial, or at least weirdly large-scale crystal formations. Maybe it is just a feature of liquid flow in a very consistent environment. Maybe if we were closer, could get better resolution, we’d see the same pattern going down, showing natural fractal-ization.

So, any point to all this? yes. Choices matter. We do have information on Pluto because NASA has a budget and some will to use it. Most of the money is trapped in bureaucracy, much of the rest goes to Goddard for Earth exploration, but a little goes to JPL for its regular “big mission.”


Getting a nuclear reactor off the ground is still impossible, due to the Greens. A political choice to demonize nuclear power as a way of reducing the spread of nuclear weapons. Weapons are made in laboratories, not reactors. I keep hoping we’ll get sense in the US, but I don’t see much sign of that happening. Without 1) better launch technology or 2) refueling options. There isn’t much hope of a chemical rocket getting good results in the outer system. Too much Delta V to overcome. I’m still betting on a good nuclear reactor and ion drive for future deep-space missions. I guess I shouldn’t hold my breath.

Space Mining

asteroidsCongress Passes the Space Act,411747

Space Mining is now legal.

So, technically, you can go mine your asteroid and bring home the materials for profit. A few small problems:

  1. No spaceship can get to the asteroids right now
  2. No mining ships have even been seriously designed
  3. No fuel depots in space
  4. No customer base for space materials

This is one of those self-squaring circles. Once you have space miners, you’ll need fuel depots, which will need/buy space materials, which it can buy from miners, who it is fueling up to go back ….

Unfortunately, absent A -> B there is not B-> A.

There were some presentations at Dragon Con about this state of affairs and I think they’ll go far. It might take a few years, decades, but I think it will happen. Robotics will lead, robotic miners, water depots. Smelters, metal printers.

The real problem lies in creating a self-sufficient world in orbit. That world can have humans in it, then there will be humans there. We’ll begin to live in space sometime, I hope soon.



Future of Space Flight – Interplanetary Civilization

The final question is “Why are we doing this at all?”

  1. The Exploration Gene?
  2. Use of Resources on Earth is Limited?
  3. Protection of the Human Race?
  4. Growth.


  1. There will always be arguments of “Because it is there,” forever and ever. Humans are like that. But honestly, seeing Earth from orbit would be awesome, but the space between Earth and Mars is full up of NOTHING. Almost as bad as space between Earth and Jupiter, Saturn, Pluto, the next star. 99.99999 % of space is nothing. The other 0.000001% is amazing views…which, since we can’t see them with the naked eye, might as well be seen with a camera.
  2. We can extract resources in space without digging up the Earth. Yeah, not so much. There are good reasons to dig up resources in space, but we can cleanly extract resources from Earth for thousands of years before we NEED anything from an asteroid. Especially considering the cost of delivering it to the Earth.
  3. Sure, I would feel “safer” with mankind an interstellar species…but if we can’t make it on Earth, we won’t survive long in space. Filtering Earth water is EASY compared to water rationing on a colony.

Colony: “What is our acceptable Cyanide level again, honey? I think we have a pressure leak in one of the grey water tubes. Well, don’t drink anything till I check for bubbles in the piss tank.” When THAT sentence is comparable to

Earth: “Gosh, I think we’ll need to start a billion dollar desalination plant again or our almond harvest may fail.”

So, 4. Growth.

Science is easy, but its really easy when no one is checking your answers. I can define a specific spectrum as a “Magnetostar, magnetic-spinning neutron star” and have people nod wisely, but … its just a model. Heck, almost everything in Astronomy is just a model. (Really, really good models, don’t get me wrong, this is science, but we can’t really check the answer, can we?)

Engineering isn’t like that. When we build something, you can kick the tires, or whatever it has, and determine if it is better than the previous model. But if you want something good in the future, start building in the present.

In time, humanity will move into space as a natural progress. We will find ways to survive in the big dark, we will extract resources – sunlight is the easy one – and build habitats. In time, we will have an Interplanetary Civilization. Each build is hard, each round of improvements will take decades. People will die. Habitats may fail. But, this is growth.

The development of one project for the International Space Station improved water reclamation from waste by over an order of magnitude. ECLSS.


Before, we only reclaimed less than 50% of water, now we reclaim 95%. A person used over a cubic foot of water a day, now that is down to cubic inches. Improvements will continue to be made, but they don’t happen automatically.

And those way-out science models drive some of these concepts. When we see a light curve that indicates something passing in front of a star, we get an idea of size. It blocks 20% of the sun’s light… wow, that’s big. It has weird gaps in it… it is cloud-like? It might be a meteor swarm, or it might be a habitat cloud.

Unfortunately, at over 1000 light years, it is unlikely that we’ll ever get answers of engineering questions from these aliens, if they exist. But, if the engineering is possible, we will do it and I’d prefer sooner to later.

The Future of Space Flight – Ion Propulsion

As I mentioned last time, in The Future of Space Flight – Nuclear Propulsion, the nuclear thermal engine is a necessary step for moving cargo and fuel in near-Earth Space. This isn’t to say that nuclear engines aren’t capable of taking us to the outer planets, but the ISP gains still leave us shipping a huge amount of fuel. In the distant future, we may have a fuel depot in the outer planets. I can envision a robotic ice station in Jovian orbit, however, it isn’t near or necessary.

I’d rather not get into the depths of ISP, there is a Wikipedia if you need it, but lets just say that the push part of a rocket has 2 parts (theoretically) the mass of the engine and the mass of the fuel. The ISP really just talks about the fuel needed. ISP of 500 means that 1 tank of fuel gets you to … lets just say 10 km/s. If your ISP changes to 1000, you’d only need 1/2 a tank of fuel to get you to 10 km/s. If your ISP goes to 10,000 – you only need 5% of the fuel your first space ship needed. This leaves out that the engine might weigh ten times more. Meh, Rocket Science is hard.

What is best for near? Ion drives. The Nuclear Thermal engine has an ISP around 1000 s. Maybe, when they cross an MWatt, they may look at one of the enhanced propulsions, which may lead to 2000 s ISP. BUT, that starts trading on excess electric power, which is excess weight. (Not as excess as all that, since you could assume that the delivery of cargo included delivery of a working nuclear reactor, but, this works with Ion drives as well.)

Ion drive? From Hall Effect to VASIMIR, they involve the same things:

  1. Heat something up a lot. (Argon, Helium, Lead) till it becomes an ionized gas. (Shoot the lead with a laser, works fine.)
  2. Confine and heat the plasma
  3. Let the Plasma Escape, slowly, at great temperature.

The VASIMIR has a low-ish ISP, around a few thousand, but the thrust can be significantly higher than Hall Effect thrusters.


VASIMIRs are good for near planets, where the balance of thrust and low fuel use gives you short mission times. You may drop the Mars trip, a distance 1 – 3 AU depending on date, to six months or less. Very reasonable. Jupiter, at a distance of 4 -6 AU, would take about a year. However, at that time, we start getting in fuel to mass ratio issues again.

The Hall Effect Thruster may have an ISP on the order of 40,000.



What does that “MEAN?” It means that a ship with a Hall Effect thruster will have a very high final velocity. It may take years to reach that velocity. Hall Thrusters usually run about a ten micro G. A push felt that would leave an adult male weighing in at 220 lbs on the Earth, at about 1 gram on the spacecraft. Literally, you couldn’t feel the thrust.

Now, Alta’s Hall thruster has much lower ISP (factor of 10) and much higher thrust (factor of 10) than theoretical, but that’s one of the trade offs. If you design a mission, the farther away you are going, the lower, constant, thrust you can deal with if your ISP is high enough.

Your final velocity could easily be in the 10’s of km/s. Velocities like that let you get to Pluto with enough fuel left to park, not just fly by into infinity. Had the mission designers agreed to a better power supply for the New Horizon mission, then they could have selected an Ion drive, and be parked around Charon as we speak.

Not that I think Pluto is anything but a big comet, but think about a decade of data, instead of one picture. That’s the future of spaceflight.



The Future of Space Flight – Nuclear Propulsion

Nuclear propulsion is the simplest thing in the world. Obviously, the word NUCLEAR is scary. Apparently, the presence of this world has destroyed more projects than the Congressional Budget Office. But still, Nuclear Thermal Propulsion, to be specific, is easy peasy lemon squeezy.

nuclear thermal propulsion

Figure 1. The simple view of a Nuclear Thermal Rocket.

To start with, you get a tank of water. Then you boil it. Then you squirt it behind you. Yeah, that’s about it. You can use Helium, Hydrogen, Water, Liquid just about anything will work. The boiling process is run by a hot nuclear fission reactor.

Now, a couple of points:

  1. It doesn’t turn off and on like your stove. It takes hours to heat up and days to cool off.
  2. The waste is slightly radioactive.
  3. The thing could melt if run too hot without propellant. So, accidents could happen.
  4. You get a lot of thrust per pound of fuel.
  5. It is very efficient. ISP around 1000, twice as good as a chemical engine.
  6. It can last for tens of years, used carefully.

Well, looking at those points, what is the engineering argument? You probably shouldn’t light one off on the ground. They save literally tons of fuel, but with a high thrust, so you can use them in a gravity well. (Super high efficiency engines often have almost no thrust, gravity and atmospheric drag can defeat their efforts.)

The best locations for nuclear rockets are planetary orbits, possibly the occasional moon landing or Mars launch. Good bang for the buck.

So, when it comes time to move Man from low earth orbit (LEO) to geosynchronous earth orbit (GEO), or even the Moon. Nuclear Rockets are the best engineering choice.

Again, we first need to develop a solid method of delivering payload and fuel to a LEO space station. Then, we need to develop a strong work horse to deliver these payloads where they need to go. A deep-space dock at a location like L2 (shown below) might be the best choice. But satellites have lots of locations to go to, a good delivery service is worth hundreds of millions each year.


Figure 2. Lagrange (L) points on a map. The closest to Earth are L1 and L2. The others could simply be called “co-orbit with Earth.”

So, when you are looking at the future of space flight. It starts with delivery to LEO, but that is too close for real space work. To get human projects out of the gravity well, we need a workhorse. I recommend a nuclear rocket for near-space travel.

The Future of Space Flight

The other day, on Facebook/Twitter, I reposted a snarky comment.

“It’s amusing seeing NASA try to use The Martian to build support for their Journey to Mars. Using hard sci-fi to help sell fantasy…”

Why can’t NASA launch a manned mission to anywhere?

  1. Because it is a bloated bureaucracy
  2. Because “safe” space travel is nearly impossible, and politicians don’t waste their precious vote capital on anything but sure things.
  3. Because it takes 10 years to do a mission. Presidents only last 8. It makes no political sense to make your predecessor a hero. Obama cancelled Bush’s Constellation, whoever comes next would cancel Obama’s mission priorities…if he had any.

JPL runs a tight ship, so I’ve been told. They put instruments on planets. However, deeply unsexy. They tried hard to sell New Horizon, I doubt anyone heard about the Pluto fly-by that didn’t have a space-geek in the family. The last popular mission was Mars, Spirit… landed in 2004. It has been a decade since “normal people” downloaded space images from the internet.

SO, NASA needs a road map that is unsexy and can be followed without glorifying the name of any sitting president, meaning cheap as well.

  1. Get to Low Earth Orbit, LEO


I love space planes. Get them up to MACH 9, hit the outer limits of the atmosphere, release the cargo. The cargo is traveling at escape velocity, a little bit of thrust and it docks with the ISS.

There is a bit of trouble with space planes, they need to be going about MACH 3 before the Scramjets will kick-on.


SO, we build an accelerator which gets them up to speed on the ground. (I prefer a 10 mile linear, but the ring is an easier picture.)

Do able? yes. Cheaper than rockets? considerably. Further, they fit into the skillset we currently have, not the one we wish we had. We know all about airplanes, we know very little about space travel. We’ve been working with balloons, gliders, and powered air vehicles since the 1700’s, rockets are new-fangled in comparison. We have MILLIONS of hours of air travel, considerably less in space. Work with what we know.

This is only step one, more soon.

Mars Radiation on the Space Track


So, I have to thank Rain (boss of the Space Track.) She knows I’ll join in on anybody’s panel and make it more fun. BUT, I really want to talk about radiation. The Martian is “hot” right now, so Mars is a hot topic. (Obviously, Mars is only hot metaphorically or figuratively, because literally it is colder than ice.)

Is radiation important for a Martian Colony? Absolutely. Oddly enough, at NASA we were asked this question many years ago. I wrote the Design Specifications for Natural Environment (pronounced Disney) for some of these missions. I’d love to go over this in great detail…but we’ll wait till Sunday morning. See ya at Dragon Con.

Asteroids – Empirical Evidence

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Oddly enough, I heard that Asteroids was one of the most popular video games ever. Well, This is a real asteroid. The Rosetta mission is creeping up on it. What can you say? It sure doesn’t look like a planet.

Deeply WTF, ya know? I mean, you can predict “sphere” you can predict a lumpy potato… but this is … um kind of spiral lines like a pull fracture. Squarish craters… I’m baffled.

Remember last week when the sun was perfectly blank? I may have forgotten to post about it, but you all are keeping up with, right? Well, if you missed it, people were wondering if we were about to fall into some super minimum. nah

Now, the activity is mostly equitorial, which is appropriate behavior for the minimum, but there is more energy farther north and south than I’m comfortable with.

This false-color image looks at activity, not to add weird terms, but you can see how the wind is blowing.

Real activity seems to be mostly constrained under 30 degrees (and consistant with solar minimum) but there is a lot of activity all the way up to 60 degrees latitude.

“Thas jus not right.” – Redneck man. (He shows up sometimes) 

So, ya know, we predict and we get smacked sometimes. We keep trying. Pieces of asteroids have been recovered on earth, but the differences between comets, asteroids, and their meteors needs a lot of empirical data. Thanks to the European Space agency for Rosetta, and thanks to NASA for STEREO – which gives us these images.