Mercury A to Z: Orbiting Mercury

Hello, friends!  Welcome back to this year’s A to Z Challenge.  For this year’s challenge, my theme is the planet Mercury, and in today’s post, O is for:

ORBITING MERCURY

On April 1, 2012 (note that date), NASA announced the discovery of a moon orbiting Mercury.  NASA went on to propose naming this newly discovered moon Caduceus, after the coiled-snake-shaped staff that Mercury carried in ancient Roman mythology.  This would have been a very exciting discovery except, of course, this was announced on April 1st.  Maintaining orbit around Mercury is hard… so hard it’s basically impossible.  The idea of a moon maintaining orbit around Mercury is so absurdly impossible that NASA thought it would make a good April Fool’s Day joke.

But for the sake of argument, let’s pretend that Caduceus is real.  Let’s pretend that Mercury does have a little, tiny moon, similar to the asteroid-like moons of Mars.  What would happen to Mercury’s moon?  Well, very rapidly, she’d find herself caught in a gravitational tug-of-war between Mercury and the Sun—and sadly, this is a tug-of-war that Mercury could never, ever hope to win.

With each successive orbit around Mercury, Caduceus would be feel the increasing and decreasing gravitational force of the Sun.  When she circles around to the dayside of Mercury, the Sun’s pull would be stronger; when Caduceus circles around the Mercury’s nightside, the Sun’s pull would be weaker.  A little stronger, a little weaker, a little stronger, a little weaker, over and over again.  If Caduceus’s orbit started off as near circular, that orbit would gradually stretch into a wider and and wider oval shape.  Eventually, inevitably, that oval would become so stretched out that it would extend beyond the reach of Mercury’s gravity.

Caduceus would not necessarily crash into the Sun after that.  Remember that every action has an equal and opposite reaction.  Every time the Sun’s gravity pulled Caduceus hard one way, she would then swing just as hard in the opposite direction.  So when the moment came and Caduceus finally broke free of Mercury’s gravity, there’s a very good chance that she would launch herself off into space like a child leaping from a swing set.

But regardless of Caduceus’s ultimate fate (crashing into the Sun or flinging herself off into space), the outcome for Mercury is the same.  He loses his moon.  Mercury will always lose his moon, no matter what.  Even artificial satellites, like MESSENGER or BepiColombo, cannot maintain orbit around Mercury for long without their thrusters.  Orbiting Mercury is really, really hard work for a spacecraft, and for a small, asteroid-like moon?  It’s basically impossible.

So if you have ever wondered why Mercury doesn’t have a moon, now you know why Mercury doesn’t have a moon.

WANT TO LEARN MORE?

Here’s NASA’s April Fool’s Day announcement about the discovery of Caduceus.

And here’s an article from Universe Today entitled “How Many Moons Does Mercury Have?” written by a good friend of this blog, Matt Williams.

Mercury A to Z: NASA Missions to Mercury

Hello, friends!  We are halfway through this year’s A to Z Challenge.  I have to admit when I picked the planet Mercury as my theme for this year’s challenge, I was a little worried I wouldn’t be able to find enough material for a full alphabet worth of posts.  But Mercury has not disappointed me.  There are more than enough Mercury facts to cover!  In today’s post, N is for:

NASA MISSIONS TO MERCURY

Which planet is closest to the Sun?  More often than not, the answer is probably Mercury.  That may seem counterintuitive, since the orbital path of Venus (the 2nd planet) lies between the orbital paths of Mercury (the 1st planet) and Earth (the 3rd planet).  But consider it this way: every time Venus and Earth happen to be on opposite sides of the Sun, Mercury is somewhere in between.  So on average, Mercury ends up being the closest planet to Earth more often than Venus, Mars, or any other planet.

And yet, despite the fact that Mercury is so close to Earth so much of the time, Mercury is still one of the absolute hardest places for Earth-launched spacecraft to reach.  The problem is the Sun.  The Sun is very big, and the gravitational pull of the Sun is very strong.  For our purposes, imagine that the Sun is “down,” and you’ll start to see what the problem is.  Flying to Mercury is an awful lot like falling toward the Sun.

Now I do want to acknowledge that I’m glossing over a whole lot of technical details here.  The purpose of this blog post is not to teach you the science and mathematics behind orbital mechanics.  All I want is to give you a small taste of what makes flying to Mercury so very challenging, so that you can better appreciate the amazing accomplishments of NASA’s Mariner 10 and MESSENGER Missions.

MARINER 10

NASA’s original plan for Mariner 10 was to aim carefully and fly by Mercury one time.  A certain Italian astronomer had a better idea, involving a never-before-attempted gravity assist maneuver near Venus.  This tricky maneuver allowed Mariner 10 to perform three flybys of Mercury for the price of one.

Gravity assist maneuvers, where a spacecraft uses a planet’s gravity to make a “for free” course adjustment, are standard practice in spaceflight today, but Mariner 10 was the first to ever attempt such a thing.  Mariner 10 was also the first spacecraft to visit two planets, collecting some data about Venus before continuing on its way to Mercury (Mariner 10 was also lucky enough to collect data from a nearby comet—another first in space exploration).

Mariner 10 flew by Mercury in March of 1974, September of 1974, and March of 1975.  During those three encounters, Mariner 10 discovered Mercury’s magnetic field and Van Allen radiation belt.  Mariner 10 also discovered Caloris Basin, Kuiper Crater, and many other important surface features.  Unfortunately, only half of the planet was in daylight during Mariner 10’s three flybys, and it was always the same half of the planet, so the other half of Mercury remained unseen and mostly unknown for decades thereafter.

Shortly after Mariner 10’s third flyby of Mercury, the spacecraft ran out of fuel for attitude control.  Without attitude control, the spacecraft couldn’t keep its communications system pointed toward Earth.  So before contact was lost, mission control ordered the spacecraft to shut down.  The now defunct spacecraft is still, presumably, orbiting the Sun somewhere near the orbit of Mercury.

MESSENGER

MESSENGER is an acronym for MErcury Surface, Space Environment, Geochemistry, and Ranging.  The name is also a reference to Mercury’s role in Roman mythology as the messenger of the gods.  The MESSENGER Mission was funded through NASA’s Discovery Program, a highly competitive program for space missions that can be done on a tight and highly-restrictive budget.

MESSENGER launched on August 3, 2004.  Unlike Mariner 10’s series of flybys, the plan for MESSENGER was to enter orbit of Mercury.  This required a much longer and more intricate flight trajectory, with one gravity assist maneuver at Earth, two at Venus, and a series of three maneuvers at Mercury to help match Mercury’s orbital velocity.  MESSENGER achieved Mercury orbit on March 18, 2011, after seven-plus years of travel.

Over the next four years, MESSENGER photographed the entire surface of Mercury (including the half of the planet Mariner 10 couldn’t see), continued to study Mercury’s magnetic field, and revealed Mercury’s internal structure through a process called gravity mapping, which involved measuring subtle variations in a planet’s gravitational field.  Oh, and who could forget this?  MESSENGER also discovered water on Mercury.  Believe it or not, there is water (frozen as ice) inside craters around the north and south poles of Mercury.

In early 2015, MESSENGER ran out of fuel, and the spacecraft’s orbit around Mercury began to deteriorate.  On April 30, 2015, MESSENGER finally crashed into the planet’s surface, giving the most heavily cratered planet in the Solar System one additional crater.

WHAT’S NEXT?

The work of NASA’s Mariner 10 and MESSENGER Missions will be continued by BepiColombo, a collaborative mission by ESA (the European Space Agency) and JAXA (the Japanese Aerospace eXplotation Agency).  I wrote about BepiColombo in a previous post.

Now I want to correct something I’ve been saying about BepiColombo in previous posts.  I’ve said that BepiColombo will arrive at Mercury in 2025; that’s not quite right.  BepiColombo will enter Mercury orbit in 2025, but much like MESSENGER, BepiColombo needs to perform several gravity assist maneuvers near Mercury first.  Two of those gravity assists have already happened, and during those maneuvers, BepiColombo already started snapping photos and gathering science data.

So every time this month that I said only two spacecraft have ever visited Mercury, that was incorrect.  BepiColombo has already become Mercury’s third visitor.

WANT TO LEARN MORE?

NASA has posted some nice articles about Mariner 10, MESSENGER, and BepiColombo on one of their educational websites.  Click these links to check them out:

NASA’s DART Mission: Rest in Peace

Hello, friends!

As you probably know, NASA’s DART spacecraft deliberately rammed itself into an asteroid on Monday.  This was a test.  It was only a test.  The asteroid in question (named Dimorphos) was never a threat to us.  Someday, though, another asteroid may come along… an asteroid that does threaten us… an asteroid that could end life as we know it.  The DART Mission was intended to test out ability to defend ourselves, should a large and genuinely threatening asteroid ever show up on our doorstep.

I spent Monday night watching NASA TV’s livestream of the DART Mission.  Those final images from DART’s navigational camera were amazing!  I never really thought about what it would look like to crash into the surface of an asteroid.  Now I know exactly what that would look like.

Anyway, today I thought I’d share a few things that I learned—things that I did not know before—while watching NASA’s livestream, as well as the press conference that was held after the mission was over.

The Space Force: So I knew DART launched almost a year ago, but I didn’t know it had launched from Vandenberg Space Force Base (I also didn’t know Vandenberg Air Force Base had been renamed).  I still think the whole Space Force thing is cringy, but at least the Space Force did help do something to actually defend our planet.  So that’s cool!
DART’s Solar Panels: In addition to testing our planetary defense capabilities, the DART spacecraft also tested a few new space technologies.  Most notably, DART was using a new, experimental solar panel design.  DART launched with its solar panels rolled up into cylinders, then the solar panels unrolled once the spacecraft was in space.  The new design apparently weighs a lot less than traditional solar panels, and anything we can do to lower the weight of a spacecraft helps make spaceflight less expensive.
Dimorphos’s Shape: This one really surprised me.  Apparently nobody knew what Dimorphos looked like until those last few minutes before impact.  The most high-res images we had were still not high-res enough to reveal the asteroid’s shape or any useful details about its appearance.  As a result, DART had to be programmed with some sort of machine learning algorithm to help it figure out what it was supposed to be aiming for.

While the DART Mission was a success, it’ll still be a while before we know exactly how effective it was at moving the orbit of an asteroid.  Telescopes up in space and down here on the ground will continue monitoring Dimorphos as the dust settles (both figuratively and literally).  Still, as a citizen of Planet Earth, I do feel a little bit safer living on this planet.  I mean, we still have a lot of challenges we need to overcome, but that asteroid problem?  I think we’ve got that one covered now.

So did you watch NASA’s livestream on Monday?  Did you learn anything new, either from the livestream or from other news sources covering the DART Mission?

P.S.: If you missed the livestream, click here to watch it on YouTube.  Or you can click here to watch the press conference that was held afterward.

NASA’s DART Mission: Brace for Impact!!!

Hello, friends!

We are only a few days away from what is, in my opinion, the #1 most important space story of the year.  No, I’m not talking about the launch of Artemis 1.  And no, this has nothing to do with the Webb Telescope either.  I’m talking about NASA’s DART Mission.

For eons now, asteroids have been zipping and zooming past our planet.  Every once in a while, one of those asteroids will hit our planet, causing anywhere from minor to major to global mass extinction event levels of damage.  But on Monday, September 27, 2022, humanity will perform our first ever experiment to see if it’s possible to smack an incoming asteroid away.

The asteroid in question is named Dimorphos.  Dimorphos is not actually a threat to us, but if we’re going to perform an experiment like this, Dimorphos is a rather convenient target for target practice.  That’s because Dimorphos is not just an asteroid; it’s also a moon (or should I call it a moonlet?) orbiting a larger asteroid named Didymos.

When the DART spacecraft crashes into Dimorphos, the force of the impact will change Dimorphos’s orbit around Didymos.  It should be fairly easy for astronomers to measure this change, and thus it should be fairly easy to judge how effective DART was—and just how effective DART would have been against an asteroid that was actually threatening us.

Oh, and just in case anyone’s concerned that DART might accidentally knock Dimorphos out of its original orbit entirely and send it hurtling our way, thus ironically causing the very disaster this mission was meant to help prevent—don’t worry.  Didymos’s gravitational hold on Dimorphos is strong.  No matter what happens on this mission, Didymos is not going to let her little moonlet go (another reason why Dimorphos was selected as the target for this experiment).

So on Monday, September 27, 2022, there will be a head-on collision between an asteroid/moonlet and a NASA spacecraft.

An Italian-built spacecraft named LICIACube will be positioned nearby to observe the experiment.  A multitude of Earth-based telescopes will also be watching.  The European Space Agency also plans to send a follow-up mission (named Hera) in 2026, to check up on Dimorphos after its post-impact orbit has had some time to settle down.

Life on Earth has never been able to defend itself from incoming asteroids before.  Life on Earth has never had the ability to even try, until now [citation needed].  Obviously asteroids are not the only threat to life on our planet.  Obviously this is not the only challenge we need to overcome.  But the DART Mission is a huge first step.  A true giant leap.  No, DART probably won’t get the same kind of love and attention as Webb or Artemis 1, but still I’d say this is the #1 most important space story of the year.  This may be one of the most important science experiments in all of Earth history.

WANT TO LEARN MORE?

P.S.: I said life on Earth has never before had the ability to defend itself from incoming asteroids.  Technically speaking, we cannot be 100% sure that’s true.  Click here to read my post on the Silurian Hypothesis.

Artemis 1: Haters Gonna Hate

Hello, friends!

My gosh, certain people sure do love doling out criticism.  Even the slightest mistake or delay, and the critics come out in droves, robed in all their smugness.  I see this all the time as a writer and an artist, and on Monday I saw a smattering of critics online smugly criticizing NASA’s Artemis Program.

On Monday morning, NASA had to scrub the launch of Artemis 1, an uncrewed test flight of the spacecraft that will soon return American astronauts to the Moon.  Apparently there was trouble with one of the engines.  Most people, I think, understand that technical problems happen and that safety must come first.  But a few folks out there saw this as an opportunity to take cheap shots at NASA, the U.S. government, and America as a whole.

Now look… (heavy sigh)… okay, there are some valid criticisms to be made about all those things.  The United States has problems.  NASA has problems.  The Artemis Program, in particular, has been politicized from the start, and whenever things get political in the U.S., bad decisions ensue.  But even if none of that were the case, even if NASA could somehow operate independently of Congress and politics, problems would still crop up.

Taking time to stop and fix the problem with Artemis 1’s engine—that’s not a sign of weakness.  That’s not a failure.  If anything, it shows that the people at NASA are doing their jobs, taking the proper precautions, and learning from past mistakes.  Ignoring the engine issue—plowing ahead with the original plan, regardless of the danger—potentially allowing a multi-billion dollar spacecraft to blow up on the launchpad?  That would have been a real failure.

But no, a few people out there think delaying the launch for a few days is a “huge embarrassment” for America.  There will always be people like this who act super smug while lobbing lazy criticism at others.  Whether you’re a national space agency or just some writer/illustrator on the Internet, try to ignore this sort of criticism if you can (or rant about it on your blog, if you must—just don’t dwell on it for too long).

WANT TO LEARN MORE?

Fran, from My Hubble Abode, posted a wonderful video on YouTube reacting to some of the nonsense people have been saying about the Artemis 1 launch delay. Click here to check it out!

Our Place in Space: The Z-Series Spacesuits

Hello, friends!  Welcome to Our Place in Space: A to Z!  For this year’s A to Z Challenge, I’ll be taking you on a partly imaginative and highly optimistic tour of humanity’s future in outer space.  If you don’t know what the A to Z Challenge is, click here to learn more.  In today’s post, Z is for…

THE Z-SERIES SPACESUITS

Oh my gosh, we actually did it.  This is the final post of this year’s A to Z Challenge!  All month long, we’ve been talking about humanity’s future in outer space.  We’ve talked about the space vehicles that will take us to other worlds, and we’ve talked about the kinds of habitats we could build on other worlds once we get there.  But there’s one thing I’m sure you’ve all been wondering about this whole time: what are people in the future going to wear?

Quite a few years ago, NASA introduced a prototype spacesuit for future missions to the Moon and Mars.  They called it the Z-1 spacesuit.  For some reason, the color scheme looked suspiciously like Buzz Lightyear.  A few years later, NASA introduced an updated design called the Z-2 spacesuit, which had glow-y parts that made it look like something out of Tron.

The Z-1 used mostly “soft” materials in its design, which gave astronauts increased mobility and flexibility; however, these soft materials did not provide much protection.  If you trip and fall on the Moon, you don’t want your spacesuit to rip or tear—not even a little bit!  So the Z-2 used a mix of soft and hard materials, in an attempt to strike a better balance between safety and mobility.

As I understand it, the really important thing is that the Z-series suits have a big, giant hatch in the back.  This hatch-back design makes it much easier to get in and out of your spacesuit, compared to more traditional spacesuit designs.  First, you open the hatch.  Next, you stick your arms in the arm tubes and your legs in the leg tubes.  Your head goes into the fishbowl part.  Then, just close the hatch behind you, and you’re good to go.  Easy!

So will astronauts in the future be wearing Z-3 or Z-4 spacesuits as they explore the Moon, Mars, and so on?  No.  No, they won’t.  I can’t find a source explicitly stating that development of the Z-series spacesuit was canceled, but I’m 99% sure development of the Z-series spacesuit was canceled.  At the very least, there hasn’t been any new news about it for years.  In the meantime, NASA has introduced other spacesuit designs, like the xEMU (eXploration Extravehicular Mobility Unit), intended for use on the Moon, Mars, etc.

It is worth nothing, though, that aspects of the Z-series designs—including the very convenient hatch in the back idea—have been incorporated into the xEMU.  Fans of the Z-1 and Z-2 suits can find some consolation in that.

Predicting the future is hard.  A lot of cool ideas have been proposed for space exploration, and quite a few of those ideas are now in active development at NASA, E.S.A., or elsewhere.  Some of the things we talked about this month may actually happen someday; others may be quietly canceled, like the Z-series spacesuits.  So whenever you see someone (like me) talking about what the future is going to be like, take what they say with a grain of salt (especially if they get hyper specific about what we’re going to do and by what date we’re going to do it).

But even if it turns out I got specific details about the future wrong, I still believe the general ideas expressed in these A to Z posts will be right.  Human civilization is going through a tough time right now, but will come out of this, we will learn from our mistakes, and we will build a better future for ourselves, both here on Earth and out there among the stars.

Want to Learn More?

Here’s an infographic from Space.com about the Z-1 spacesuit, and here’s their infographic about the Z-2.

Also, here’s a short video from NASA about the xEMU spacesuit, which borrows that super convenient hatchback design from the Z-series suits.

Our Place in Space: Yestersol

Hello, friends!  Welcome to Our Place in Space: A to Z!  For this year’s A to Z Challenge, I’ll be taking you on a partly imaginative and highly optimistic tour of humanity’s future in outer space.  If you don’t know what the A to Z Challenge is, click here to learn more.  In today’s post, Y is for…

YESTERSOL

Do you ever feel like there just isn’t enough time in your day?  Like you just cannot get everything you need to do in a day done in a day?  Do you wish your day could be just a little bit longer?  If so, moving to Mars might be a good solution for you!  A day on Mars is nearly 40 minutes longer than a day on Earth!  Scientists call this slightly longer Martian day a “sol,” and several cute and clever new words have been introduced related to Martian timekeeping: words like yestersol, tosol, and solorrow.

As of yet, there are no humans on Mars (citation needed), but there are humans here on Earth who have to live and work and plan their whole schedules according to Mars time.  You see, the Mars rovers can only operate during Martian daylight hours.  Therefore, everyone back at mission control for those rovers needs to be awake, alert, at their desks and ready to go when it’s daytime on Mars (regardless of what time it is here on Earth).

Sometimes the discrepancy between a Martian sol and an Earthly day isn’t so bad.  Sometimes, when it’s daytime at Jezero Crater (current location of the Perseverance rover), it’s also daytime in southern California (where Perseverance mission control is headquartered).  But day after day, sol after sol, that forty minute difference adds up.  At some point, high noon at Jezero crater will be the middle of the night in southern California.

It’s important that the same crew of people always works with the same rover.  Therefore, NASA has had special clocks and watches made to help people keep track of what time it is on Mars.  NASA scientists and engineers associated with various Mars missions set their work schedules, meal schedules, and sleep schedules according to Mars time.  As a result, there is a small community of “Martians” here on Earth, living their lives about forty minutes out of sync from the rest of us.  And quite naturally, certain colloquial terms have developed within this little community of Mars researchers.

Yestersol refers to the sol before the current sol.  Tosol is the current sol.  And solorrow is the next sol, after the current sol.  Making a clear distinction between “yesterday” and “yestersol” is especially important for people who live on Earth and still have to deal with many Earthly concerns, but who also, in a very real way, need to think and act as if they’re living on Mars.

I like to think of the whole “yestersol, tosol, solorrow” phenomenon as a little preview of the future.  It’s one thing to think about big picture futuristic stuff, like space elevators and planetary protection laws; but it’s little bits of culture and daily life (sorry, sol-ly life) that help make the future feel like a real place.

Want to Learn More?

NASA spacecraft engineer Nagin Cox gave a really neat TED Talk about what it’s like living on Mars time.  Click here to watch it.

Our Place in Space: Xanadu

Hello, friends!  Welcome to Our Place in Space: A to Z!  For this year’s A to Z Challenge, I’ll be taking you on a partly imaginative and highly optimistic tour of humanity’s future in outer space.  If you don’t know what the A to Z Challenge is, click here to learn more.  In today’s post, X is for…

XANADU

`Titan is the largest moon of Saturn.  It’s a very cold place.  It’s so cold on Titan that water is basically a kind of rock, and certain chemicals that we typically think of as gases (i.e.: methane and ethane) flow freely as liquids.  As a result, the surface of Titan looks surprisingly similar to some regions on Earth: a rocky landscape eroded by rain and rivers.  Except the “rock” is frozen water, and the rain and rivers are a mix of liquified methane and ethane.  One of the most curiously familiar “rock” formations on Titan lies near the equator.  It’s called Xanadu.

Xanadu is an Australia-sized region of craggy hills and mountains.  Due to Titan’s thick, hazy atmosphere, it’s impossible to see Xanadu (or any other surface feature on Titan) except in certain specific wavelengths, such as certain wavelengths of infrared.  When Xanadu is visible, it appears as a bright splotch on Titan’s surface, surrounded by much darker desert terrain.

It’s unclear how Xanadu came to be.  One hypothesis I read argues that Xanadu could be associated with some sort of giant impact event.  Perhaps a large asteroid or comet smashed into Titan, disrupting the icy crust, which then refroze as this jagged and craggy terrain.  Another hypothesis suggests that Xanadu was created by some sort of tectonic activity—a fascinating possibility.  At this point, Earth is the only world confirmed to have plate tectonics.

In this Our Place in Space series, I’ve tried to emphasize all the cool and exciting things humans could do in the distant future.  I have also mentioned, from time to time, my belief that humans in the distant future will learn to be good stewards of the Earth.  Space exploration can help us do that.  Titan is so curiously familiar, yet also so weirdly different from Earth.  Trying to understand why Titan is so different-yet-similar can teach us much about our own world—which, in turn, will help us figure out how to take better care of our planet.

But there’s a catch.  Just as we have a responsibility to take better care of Earth, we also have a moral responsibility to not mess up Titan.  Remember Titan’s thick, hazy atmosphere?  There are some weird chemicals forming in that atmosphere.  Organic chemicals.  Could those organic chemicals be associated, in one way or another, with biological activity?  Maybe.  Maybe not.  No one can say at this point.

In the next few years, NASA will be sending a robotic helicopter to explore Titan’s Shangri-La region, one of the dark-colored regions directly adjacent to Xanadu.  If we’re lucky, maybe that robo-helicopter will venture into Xanadu at some point.  I have confidence that NASA will thoroughly sterilize all of their equipment before sending it to Titan to ensure that we do not contaminate Titan with our Earth germs.

There will be many more missions to Titan in the future.  Just as Mars is crawling with Mars rovers today, Titan will be covered in Titan rovers, Titan helicopters, and Titan submarines in the future.  The place has too much in common with Earth, and we simply cannot leave it unexplored.  But humans in the distant future will not only be good stewards of the Earth; they’ll be good stewards of the Solar System.  And so, whether we’re exploring Xanadu or Kraken Mare or Shangri-La, or any other region on Titan that has a super cool name, strict safety precautions will always be a must.

Want to Learn More?

I had a really hard time finding information about Xanadu for this post.  I’m guessing that’s because very little information is available at this time.  More exploring needs to be done! What I did find came from these three scientific papers:

Our Place in Space: The Rocket Equation

Hello, friends!  Welcome to Our Place in Space: A to Z!  For this year’s A to Z Challenge, I’ll be taking you on a partly imaginative and highly optimistic tour of humanity’s future in outer space.  If you don’t know what the A to Z Challenge is, click here to learn more.  In today’s post, R is for…

THE ROCKET EQUATION

Are you bad at math?  That’s okay.  I’m bad at math too.  I try to avoid talking about math on this blog because I know a lot of my readers are still traumatized by high school math classes, but also because I don’t feel I’m qualified to explain math anyway.  So in today’s post, we’re going to talk about what the rocket equation means and why it’s so important without talking about what the rocket equation actually is or how it works.

As you know, you need fuel to go to space.  If you’re a rocket scientist, the rocket equation tells you how much fuel you need to reach any specific destination in space.  You want to travel from Earth to the Moon?  Plug some numbers into the rocket equation, and the equation will tell you how much fuel you need.  Want to go from the Moon to Jupiter?  Plug new numbers into the equation, and it’ll tell you how much fuel you need for that trip.  It always ends up being an absolutely ridiculous amount of fuel.

When you see space vehicles sitting on the launch pad, something like 85% to 90% of the mass of that space vehicle is fuel.  The rocket equation demands that it be so.  For the sake of comparison, fuel makes up about 30% to 40% of the mass of an airplane, or about 4% of the mass of a car.  NASA famously refers to this as “the tyranny of the rocket equation,” because NASA is the American space agency, and whenever Americans don’t like something that call it tyranny.

With a little creative engineering, rocket scientists can make marginal improvements to a rocket’s fuel efficiency—a 1% or 2% improvement, perhaps!  But that’s about it.  The rocket equation is unforgiving, and it offers very little wiggle room.  In other words, the rocket equation means that space exploration is super expensive, and it always will be, unless and until we invent some totally new Sci-Fi propulsion system that no longer requires rocket engines.

As a science fiction writer, I’m perfectly happy to dream up propulsion systems that ignore the rocket equation.  But for the purposes of this “Our Place in Space” series, I’m trying to stick to more realistic science, which means that the distant future we’ve been exploring in these blog posts is still very much constrained by the rocket equation.

We humans can still do a lot under those constraints.  We can get to the Moon (we’ve done it before!), and we can get to Mars and the asteroid belt as well.  Most of the outer Solar System is within our reach—in time, perhaps the entire outer Solar System could be ours.  But there are limits.  So long as we’re still using rockets for space travel, there will always be limits on how far humans can go.

Want to Learn More?

Check out NASA’s “The Tyranny of the Rocket Equation” article, which goes into more detail about why the rocket equation matters.  There’s also some colorful language in there about “revolting against tyranny.”

And for those of you who do want to see the math, here you go.  Enjoy!

Our Place in Space: NIAC

Hello, friends!  Welcome to Our Place in Space: A to Z!  For this year’s A to Z Challenge, I’ll be taking you on a partly imaginative and highly optimistic tour of humanity’s future in outer space.  If you don’t know what the A to Z Challenge is, click here to learn more.  In today’s post, N is for…

NIAC

So far this month, we’ve talked about some pretty wild ideas for future missions in space.  We’ve talked about building an elevator to space.  We’ve talked about putting a radio telescope on the far side of the Moon.  We’ve talked about sending astronauts to Callisto, one of the moons of Jupiter, and exploring the hydrocarbon lakes on Titan (a moon of Saturn) using a robotic submarine.  As crazy as these ideas may seem, they’ve all received some amount of funding from NASA through a program called NIAC.

NIAC stands for NASA Innovative Advanced Concepts (yes, it’s an acronym that contains another acronym inside it).  NIAC is basically a program that awards grant money to researchers who are testing the limits of what we can do in space using current technology or who are developing new technologies that might one day revolutionize space exploration.  If you ever hear on the news that NASA is funding some project that sounds a little too Sci-Fi to be true, it probably just means that NASA gave somebody some NIAC funding for their research.

I once heard NIAC described as a high-risk/high-reward program.  Many NIAC projects probably won’t work out.  Some of these things really are too Sci-Fi to be true.  But what if a few NIAC projects do work?  What if some crazy idea that sounds like pure science fiction actually works!?!  Even if only a few NIAC funded projects do come to fruition, they could change everything for NASA.  More than that, they could change everything for human civilization.

I’m no expert on finances.  I’m certainly no expert on how the U.S. federal budget works.  I do know that space exploration is expensive.  Very expensive.

I also know that NASA does what it does within a very strict and rather inflexible budget.  I’m actually really impressed that NASA manages to do so much cool science stuff on such a tight budget.  This may seem weird, but I often ask myself “What would NASA do?” when I have to make difficult spending decisions.

Most NIAC projects are definitely not ready to fly and probably won’t be ready to fly for quite a few years to come.  But it makes sense to start planning for the future now.  It makes sense to do some of the research now that could help make a more Sci-Fi future become a reality.  That’s really what NIAC is all about.

Want to Learn More?

Wikipedia has a pretty thorough list of all the research projects that have received NIAC funding over the years, up to 2020.

Additionally, here’s a listing of NIAC funded projects from 2021, and here’s the listing for 2022.