The Titan Mission That Could’ve Been

July 31, 2017

This is a follow-up to my recent post about NASA’s next flagship-class mission. There seemed to be a lot of interest in the comments about a possible mission to Titan and/or Enceladus, Saturn’s most famous moons.

The competition for flagship mission funding can get pretty intense. The Titan Saturn System Mission (or T.S.S.M.) was a strong contender last time around, as was a proposed mission to Europa, the most watery moon of Jupiter.

According to Titan Unveiled by Ralph Lorenz and Jacqueline Mitton, things got a little nasty when the Europa team started calling Titan “Callisto with weather,” the implication being that Titan was geologically boring.

Callisto, by the way, is a large by often overlooked moon of Jupiter.

Ultimately Team Europa won. NASA deemed their proposal to be closer to launch-readiness. Now after a few years delay due to a certain global financial meltdown, the Europa Clipper Mission appears to be on track for a 2022 launch date (fingers crossed).

As excited as I am for Europa Clipper, the mission to Titan would’ve been really cool too. It actually would have included three—possibly four—spacecraft.

  • A lake-lander to explore Titan’s liquid methane lakes.
  • A hot air balloon to explore the organic chemical fog surrounding Titan.
  • A Titan orbiter to observe Titan from space and also relay data from the lander and balloon back to Earth.
  • And a possible Enceladus orbiter, built by the European Space Agency, which would have tagged along for the ride to Saturn.

It’s a shame T.S.S.M. didn’t get the green light from NASA. Just think: we would’ve had so many cool things going on at once in the Saturn System, enough to almost rival the activity we’ve got going on on Mars!

But now once Europa Clipper is safely on its way (again, fingers crossed), Team Titan will have another shot at getting their mission off the ground.

NASA’s Next Flagship Mission

July 19, 2017

Let’s imagine you’re NASA. You have two big flagship-class missions coming up: one to search for life on Mars (launcing in 2020) and another to search for life on Europa (launching in 2022). These flagship missions are big, expensive projects, so Congress only lets you do one or two per decade.

After 2022, the next flagship mission probably won’t launch until the late 2020’s or early 2030’s, but still… now is the time for you to start thinking about it. So after Mars and Europa, where do you want to go next? Here are a few ideas currently floating around:

  • Orbiting Enceladus: If you want to keep looking for life in the Solar System, Enceladus (a moon of Saturn) is a good pick. It’s got an ocean of liquid water beneath it surface, and thanks to the geysers in the southern hemisphere, Enceladus is rather conveniently spraying samples into space for your orbiter to collect.
  • Splash Down on Titan: If there’s life on Titan (another moon of Saturn), it’ll be very different from life we’re familiar with here on Earth. But the organic chemicals are there in abundance, and it would be interesting to splash down in one of Titan’s lakes of liquid methane. If we built a submersible probe, we could even go see if anything’s swimming around in the methane-y depths.
  • Another Mars Rover: Yes, we have multiple orbiters and rovers exploring Mars already, but some of that equipment is getting pretty old and will need to be replaced soon. If we’re serious about sending humans to Mars, it’s important to keep the current Mars program going so we know what we’re getting ourselves into.
  • Landing on Venus: Given the high temperature and pressure on Venus, this is a mission that won’t last long—a few days tops—but Venus is surprisingly similar to Earth in many ways. Comparing and contrasting the two planets taught us how important Earth’s ozone layer is and just what can happen if a global greenhouse effect get’s out of control. Who knows what else Venus might teach us about our home?
  • Orbiting Uranus: This was high on NASA’s list of priorities at the beginning of the 2010’s, and it’s expected to rank highly again in the 2020’s. We know next to nothing about Uranus or Neptune, the ice giants of our Solar System. Given how many ice giants we’ve discovered orbiting other stars, it would be nice if we could learn more about the ones in our backyard.
  • Orbiting Neptune: Uranus is significantly closer to Earth than Neptune, but there’s an upcoming planetary alignment in the 2030’s that could make Neptune a less expensive, more fuel-efficient choice. As an added bonus, we’d also get to visit Triton, a Pluto-like object that Neptune sort of kidnapped and made into a moon.

If it were up to me, I know which one of these missions I’d pick. But today we’re imagining that you are NASA. Realistically Congress will only agree to pay for one or two of these planetary science missions in the coming decade. So what would be your first and second choices?

Sciency Words: Frost Line

December 23, 2016

Welcome to a very special holiday edition of Sciency Words! Today’s science or science-related term is:


When a new star is forming, it’s typically surrounded by a swirling cloud of dust and gas called an accretion disk. Heat radiating from the baby star plus heat trapped in the disk itself vaporizes water and other volatile chemicals, which are then swept off into space by the solar wind.

But as you move farther away from the star, the temperature of the accretion disk tends to drop. Eventually, you reach a point where it’s cold enough for water to remain in its solid ice form. This is known as the frost line (or snow line, or ice line, or frost boundary).

Of course not all volatiles freeze or vaporize at the same temperature. When necessary, science writers will specify which frost line (or lines) they’re talking about. For example, a distinction might be made between the water frost line versus the nitrogen frost line versus the methane frost line, etc. But in general, if you see the term frost line by itself without any specifiers, I think you can safely assume it’s the water frost line.

Even though our Sun’s accretion disk is long gone, the frost line still loosely marks the boundary between the warmth of the inner Solar System and the coldness of the outer Solar System. The line is smack-dab in the middle of the asteroid belt, and it’s been observed that main belt asteroids tend to be rockier or icier depending on which side of the line they’re on.

It was easier for giant planets like Jupiter and Saturn to form beyond the frost line, since they had so much more solid matter to work with. And icy objects like Europa, Titan, and Pluto—places so cold that water is basically a kind of rock—only exist as they do because they formed beyond the frost line. This has led to the old saying:


Okay, maybe that’s not an old saying, but I really wanted this to be a holiday-themed post.

All These Worlds Are Yours: A Book Review

October 11, 2016

In his book All These Worlds Are Yours: The Scientific Search for Alien Life, author Jon Willis gives you $4 billion. How many authors do that? Okay, it’s imaginary money, and you’re only allowed to spend it on astrobiological research. But still… $4 billion, just for reading a book!

If you’re new to the subject of astrobiology, All These Worlds is an excellent introduction. It covers all the astrobiological hotspots of the Solar System and beyond, and unlike most books on this subject, it doesn’t gloss over the issue of money.

There are so many exciting possibilities, so many opportunities to try to find alien life. But realistically, you can only afford one or maybe two missions on your $4 billion budget. So you’ll have to pick and choose. You’ll have to make some educated guesses about where to look.

Do you want to gamble everything on Mars, or would you rather spend your money on Titan or Europa? Or do you want to build a space telescope and go hunting for exoplanets? Or donate all your money to SETI? Willis lays out the pros and cons of all your best options.

My only complaint about this book is that Enceladus (a moon of Saturn) didn’t get its own chapter. Instead, there’s a chapter on Europa and Enceladus, which was really a chapter about Europa with a few pages on Enceladus at the end.


I agree, Enceladus. On the other hand, Enceladus is sort of like Europa’s mini-me. So while I disagree with the decision to lump the two together, I do understand it.

In summary, I’d highly recommend this book to anyone interested in space exploration, and especially to those who are new or relatively knew to the subject of astrobiology. Minimal prior scientific knowledge is required, although some basic familiarity with the planets of the Solar System would help.

P.S.: How would you spend your $4 billion? I’d spend mine on a mission to Europa, paying special attention to the weird reddish-brown material found in Europa’s lineae and maculae.

Sciency Words: Macula

September 9, 2016

Sciency Words PHYS copy

When Voyager 1 trained its camera on the moons of Jupiter, scientists back on Earth had no idea what to expect. Turned out they were right. Voyager was snapping photos of geological features unlike anything anyone had ever seen before. Which meant it was time to make up some new sciency words!


Last week, we talked about Europa’s lineae: the reddish-brown cracks and fissures crisscrossing this small moon’s surface. But those weren’t the only surprises Voyager 1 observed. Let’s zoom in for a closer look.

Sp09 Macula on Europa

Europa has these peculiar dark splotches on its surface, similar in coloration to the lineae. Scientists came up with the term macula (plural maculae) to describe them. It comes from the Latin word for “spot” or “blemish.” It’s related indirectly to the word immaculate, which literally means “without blemish.”

Although Europa’s maculae were discovered in 1979, it wasn’t until 2011 that anyone could adequately explain them. It seems that Europa’s thick ice shell has a complex relationship with the ocean of liquid water deep beneath the surface, resulting in frequent patterns of melting and refreezing.

Sometimes “lakes” of liquid water become embedded between layers of ice. This causes surface ice to sag and cave in, breaking up into chunky, tightly packed icebergs. Some sort of material (possibly organic material) seeps up with the meltwater, causing the dark discoloration.

Eventually, the lake beneath a macula will freeze. Since ice is less dense than water, this forces the now cracked and broken surface ice to rise above the surrounding landscape. In the process, the already strange-looking maculae transform into even stranger-looking chaos terrain.

The term macula can be used to describe almost any dark, spotty or splotchy feature on a planetary body. That doesn’t mean they have anything in common beyond superficial appearances. For example, while maculae on Europa seem to be caused by melting and refreezing ice, maculae on Titan may be related to some sort of volcanic activity.

For next week’s edition of Sciency Words, we’ll move on to Ganymede. Europa wasn’t the only Jovian moon showing off strange, never-before-seen geological features when Voyager arrived.

Sciency Words: Linea

September 2, 2016

Sciency Words MATH

When Voyager 1 trained its camera on the moons of Jupiter, scientists back on Earth had no idea what to expect. Turned out they were right. Voyager was snapping photos of geological features unlike anything anyone had ever seen before. Which meant it was time to make up some new sciency words!


Europa has the youngest, smoothest-looking surface of any object in the Solar System.

Ag04 Europa Blush

But as you can see in the totally legit Voyager 1 image above, Europa’s icy blue surface is not without blemish.

It’s crisscrossed with cracks and fissures that appear to be filled with some sort of reddish-brown substance. Astronomers adopted the term linea (plural lineae) to describe these features. This was not astronomers at their most creative or imaginative; linea is just the Latin word for line.

Europa has a subsurface ocean of liquid water. There might be alien sea creatures swimming around in that subsurface ocean. Or there might not. If we want to find out, Europa’s lineae may be a good place to start looking.

The reddish-brown substance is believed to seep up through the cracking, fissuring ice. Does it include organic material? Amino acids? Maybe some sort of alien DNA? Hopefully NASA’s Europa Clipper mission will be able to find out (pending Congressional approval and so forth).

Lineae are most commonly associated with Europa, but the term has also been used to describe line-like features on a handful of other worlds, including Mars (although Mars’s recurring slope lineae are very different from lineae on Europa).

In next week’s edition of Sciency Words, we’ll continue exploring the moons of Jupiter. There are plenty of other terms that had to be invented following Voyager 1’s visit.

P.S.: I once ate at a seafood restaurant named Nova Europa. I know it was supposed to be Mediterranean-themed, but that is not what I was thinking about when they served my calamari.

Europa: My Favorite Moon

March 16, 2016

Fun fact about me: Europa is my favorite moon.

Mr07 Moon 1

Oh, sorry Moon. You’re cool too. It’s just… you don’t have an ocean. Or chaos terrain. Or possible alien life. It’s nothing personal.

Mr07 Moon 2

Anyway, on Monday I told you that Congress wants NASA to put a robotic lander on the surface of Europa. But the really interesting bit is deep beneath the surface, where the ice turns to liquid water. Is anything alive down there? Any microbes? Maybe fish? What about alien mermaids?

A lander can’t investigate that sort of stuff. At least not directly. But if you’ve ever seen a picture of Europa…

Mr07 Europa

… you’ll notice the surface is covered in dark reddish-colored lines. These lines appear to be cracks. It’s believed that warm water sometimes forces its way to the surface, carrying with it a mix of minerals and possibly other materials from the oceans below. It’s these minerals which cause the reddish discoloration.

So while a lander can’t sample the ocean water directly, it could examine the materials that have been deposited on the surface. Now, if you’ll allow me to switch my science blogger hat for my science fiction writer hat, I’ll tell you exactly what the Europa lander will find.

Salt. Lots of salt. That won’t surprise anyone. It’s been long assumed that Europa’s ocean is much saltier than the oceans here on Earth. It must be; otherwise the ocean would freeze.

The lander will also detect other minerals as well. And amino acids. That’ll raise some eyebrows, but amino acids aren’t that uncommon. We’ve found them on other planets and we’ve found spectrographic evidence of them all across space. As I reported in last week’s Molecular Monday post, there are literally hundreds or perhaps thousands of different kinds of amino acids in our universe.

Mr07 Surface of Europa

That will make headlines. No, it’s not the same 21 amino acids coded for by human DNA, but this cannot be a coincidence. What natural phenomenon, other than life, could produce such a select few amino acids in such large quantities?

But wait, there’s more. These 21 amino acids have something in common. They have the same chirality. And that’s the part where the entire scientific community freaks out.

Tune in for Friday’s edition of Sciency Words to find out what the heck chirality is and why it’s so important in the search for alien life.

P.S.: My second favorite moon is Titan, followed by Io, Miranda, and Triton. Oh, and Naiad! I love Naiad. But Earth’s Moon totally makes in my top ten. Probably.