Seveneves

In Neal Stephenson’s 2015 novel, the Human Race does its best to deal with an oncoming planetary catastrophe, a 5,000 year bombardment of Earth. Most of the page count is spent on a desperate effort to preserve a fraction of humanity off the Earth’s surface in space. We are repeatedly forced to follow the Gimli Philosophy of Risk Management: "Certainty of death, small chance of success... What are we waiting for?” Because when those are the options, the answer is obvious. You play the cards you are dealt as well as you can, and if you lose you go down fighting.

Stephenson does a pretty good job of sticking to known science, with, he admits, a few places where he wrote himself into a corner. It follows that settling space with today’s technology is shown as the kind of desperate enterprise that is only attempted because an unknown Agent destroys the fricking Moon. And the settlers barely survive by the skin of their teeth, passing through the narrowest of genetic bottlenecks after terrible casualties.

Early on, the alert reader will notice Stephenson introducing Checkov’s Survival Plans B and C. 5,000 years later he takes them down off the wall. Because, even for this planetary catastrophe settling space isn’t the only option, or necessarily the best one.

It isn’t explicitly stated, but is logical to assume that there were other iterations of Plan B, and Sonar Taxlaw’s people are just the one that we meet before the end of the book.

Also, Sonar Taxlaw is the best character name since Leelo Dallas Multipass.

Heinlein’s Double Star Could Not Win a Hugo Today

Because the science is rubbish, and we know it. This is a real problem for contemporary hard SF: the universe is not nearly as hospitable to space travel as we once thought, and it’s a lot harder to write about robust human settlement beyond Earth without cheating on the science than we thought in the 1950s.

The Size of New Horizons

New Horizons is often described as the size of a grand piano. Somehow it pleases me to come from a culture that calibrates the size of spacecraft in musical instruments.

On Pluto's Doorstep

New Horizons has entered Pluto's Hill Sphere, the space where Pluto's gravity dominates that of the Sun. Pluto and Charon are starting to look like actual places rather than discs covered with low resolution blotches. And it gets better. The closest approach will be July 14th.

New Horizons will streak through Pluto space at 13.8 km/sec. It left Earth faster than any other spacecraft, and it took almost 9 1/2 years to get there. Next stop, deeper into the Kuiper Belt.

These are the days of miracle and wonder.

What to expect when you're expecting a flyby.

More on The Hot Equations

Another objection to Ken Burnside's The Hot Equations is that he spends a lot of time on the performance of electric propulsion (at current performance levels) and nuclear thermal rockets (tested experimentally, but not yet ready for operational missions.) While this technology will support a great deal of interesting exploration, I don't think it will support interplanetary commerce worth fighting a space war over. That will probably require something with higher performance, like a VASIMIR engine or a fusion pulse drive.

About The Hot Equations

Ken Burnside makes a brave attempt to discuss the actual implications of thermodynamics in space warfare. It is on the 2015 Hugo ballot for Best Related Work. Unfortunately, he gets a lot wrong.

In space, the horizon assumption is almost always wrong. The one exception is Low Earth Orbit (LEO), where the limb of the earth can temporarily obscure something for roughly an eighth of an orbital period; this is about a 15-minute window, tops. Detection range is never limited by terrain for militarily significant increments of time. 

Not true for sufficiently distant observers. For an observer on Mars or Ceres, a ship in LEO is going to be eclipsed almost half an orbital period. In a hostile environment, this is exactly when the Earth ship would choose to make major delta-v changes.

With an emissions spectrum on your drive flare, plus distance and proper motion, they can determine the mass pushed by that drive flare. Making your spacebattleship look like a space rowboat doesn't work, and neither do decoys, which need the same drive signature, apparent motion, and mass as the ship they're duplicating. 

You can’t make a battleship look like a rowboat, but you can make a rowboat look like a battleship. A rocket engine is designed to convert as much of the energy used as possible into accelerating propellant. A mechanism designed to simply produce the same amount of heat and lighter will be lighter, simpler, cheaper and use less energy. Compare, for example a welding torch to a rocket engine with the same thermal output. Similarly, a craft with electric propulsion could route electricity directly to radiators to simulate the heat signature of a much more massive craft.

The usual counter-argument made is "I'll just drift in, with engines cold and go undetected." Your life support system and power plant will be a detectable signal once your engine turns off, and they'll know where to look. 

Again, a decoy can have a heat source to simulate a manned ship running without thrust. And unmanned ships can hibernate while not under thrust, with very low power output. We’ve already shown that unmanned craft can be lethal weapons platforms, even when operating in the unpredictable environment of an atmosphere with weather.

The ion thrusters used by NASA's probes to Pluto have ISPs of around 10,000 seconds with a thrust of around 4milligees. 

NASA’s one probe to Pluto, New Horizons, does not use ion thrusters. The author is evidently thinking of Deep Space 1 and Dawn, both asteroid missions.

The combat actions won't be naval in nature, at least in the conventional Battleof Jutland sense. They'll be closer to anti-piracy actions in the Sea of Cebu or the Gulf of Aden; a pirate will lay in wait at a point where a ship must make a course correction – and where missing that correction by a few hours can result in everyone aboard dying of starvation – and capture the ship to hold for ransom.  

This shows a profound misunderstanding of orbital mechanics. First, most cargo missions won’t need a crew and won’t have one. Second, capturing a ship at interplanetary speeds is much easier said than done.

Consider a specific scenario: the asteroid pirates in Poul Anderson’s 1966 The Moonrakers. Robot freighters travel on Hohmann Orbits between Mars and the Jovian Moons, and space pirates from the asteroids match courses and loot them as they pass through the asteroid belt. There are several problems with this concept.

Simply matching courses takes a lot of delta-v, even if the most efficient course is chosen, and the most efficient course is a very long haul for the pirate crew. Getting away with the loot requires still more delta-v, and another long haul for the pirate crew. For most goods, it’s probably cheaper to buy honestly in Mars orbit and ship to the belt on a robot freighter.

Second, if Burnside is correct that plausible space drives are visible at great distances, it will be quite difficult for the pirates to either achieve surprise or get away without being tracked and targeted. 

Third, reliably disabling enough of the freighter’s systems to make it safe to board without damaging the cargo will be tricky, even if the pirates can achieve surprise. And I can imagine a lot of ways a bloody-minded owner could booby trap a ship so that unauthorized boarding becomes too risky for any rational pirate.

SpaceX Crashes and Burns, Again

If your stated goal is to land the first stage of your rocket on a barge in a condition suitable for reuse, then landing on the barge in such a way that the stage topples over and explodes is not actually a success.

I''m sure they learned valuable lessons about how to do it better next time. But spectacular success?  I don't see it.

Name a Crater on Mercury

Immortalize an important person in the Arts and Humanities from any nation or cultural group by having a crater on the planet Mercury named in their honor! The MESSENGER Team is seeking help from all Earthlings to suggest names for five impact craters on Mercury. We will accept submissions beginning midnight (00:00 UTC) December 15, 2014 until January 15, 2015 (23:59 UTC). All entries will be reviewed by Team representatives and expert panels. Then, 15 finalist names will be submitted to the International Astronomical Union (IAU) for selection of the 5 winners. Winning submissions will be announced by the IAU to coincide with MESSENGER’s End of Mission Operations in late March/April 2015.

Details here.

According to the IAU rules for Mercury, impact craters are named in honor of people who have made outstanding or fundamental contributions to the Arts and Humanities (visual artists, writers, poets, dancers, architects, musicians, composers and so on). The person must have been recognized as an art-historically significant figure for more than 50 years and must have been dead for at least three years.

I have submitted Christine de Pizan and Cab Calloway.

When I make a submission using a Mac with Safari as a browser, the second page appears blank until I scroll up. I then see the relevant requests for additional reference documentation.

Cab Calloway (1907-1994)

Cabell "Cab" Calloway III was a jazz singer and bandleader, well known for his performances at Harlem's Cotton Club and scat singing.

His music was worked into several of Fleischer Studios' Betty Boop cartoons, including "Minnie the Moocher", in which Calloway provided the voice for a spectral walrus.

That's right, a spectral walrus. You can't make this up. At least, I can't.

He created music that people loved, and that is worthy of some appropriate memorial. Like a crater on Mercury, where they name craters after artists.

2015 in Space

It should be interesting.

In January, SpaceX will attempt to land the first stage of an orbital launcher on a barge. If they fail, they'll try again.

In April, Dawn should enter Ceres orbit.

In May, the Planetary Society should launch a solar sail spacecraft.

In July, New Horizons should fly by Pluto.

In November, Japan will make another attempt to put their Akatsuki spacecraft in Venus orbit.

The flotilla of Mars orbiters and surviving rovers will continue to probe Mars. Cassini continues to explore the Saturn system.

2014 in Space

China put their Chang'E lander and Yutu rover on the the  Lunar surface late in 2013, and they continued to send back data in 2014. It was the first soft landing on the Lunar surface since the Soviet Luna 24 in 1976.

In July, the Opportunity rover surpassed the record of Lunokhod 2 for the greatest distance driven on a world other than Earth. By then, Opportunity had spent more than ten years exploring Mars.

On September 24, India put their Mars Orbiter Mission spacecraft into Martian orbit, a few days after NASA's MAVEN spacecraft also arrived in orbit around Mars. India becomes the fourth space agency to reach Mars orbit, and the first to do so on their first try.

This brought the international flotilla of Mars orbiters to five, plus two rovers on the surface.

In November, the European Space Agency's Rosetta spacecraft, orbiting the rubber-duck shaped comet 67P/Churyumov–Gerasimenko, dropped the little Philae lander to the surface, where it bounced across the unexpectedly crunchy crust of the comet nucleus.

In December, NASA's Dawn spacecraft began to capture images of Ceres, Japan launched their Hayabusa 2 spacecraft to visit an asteroid and bring back samples, NASA launched an unmanned test flight of their Orion capsule, and NASA's New Horizons spacecraft woke from hibernation approaching Pluto. Also, three potential Kuiper Belt targets have been identified for New Horizons after Pluto.

Also, the Curiosity rover reports that something is intermittently pumping methane into the Martian atmosphere. It could be something non-biological, but still, very interesting.

All in all, a good year in space.

For getting to space, it was rockier.  On August 22, the usually reliable Soyuz launcher put two Galileo satellites in the wrong orbit. On October, 28, an Antares launcher failed shortly after liftoff, fell back to the ground and exploded. On October 31 , a SpaceShipTwo suborbital rocket plane broke up in flight, killing one of the crew, 39 year old Michael Tyner Alsbury.

Space is hard. All the more reason to appreciate the successes.

A Good Week in Space

During the first week in December:

On December 1, NASA's Dawn spacecraft captured an image of Ceres. It does not yet rival images from Hubble, but wait for it. Dawn did a spectacular job mapping Vesta, and will do the same for Ceres, if all goes according to plan.

On December 2, (EST) Japan launched their Hayabusa 2 spacecraft to visit an asteroid, drop off landers, and return with a sample.

On December 5, NASA launched their unmanned test flight of an Orion spacecraft on an almost flawless mission to a apogee of 3,600 miles. A spacecraft capable of carrying humans hasn't been this far from Earth since Apollo 17 in 1972.

As a taxpayer, I appreciated the live transmission of images of the receding earth and parachute deployment from inside the spacecraft, and capsule reentry and parachute deployment from a circling drone. I didn't get this during Apollo. This is good policy. I like to see what I am paying for. If I can, I will pay more cheerfully.

On December 6, New Horizons awoke from hibernation on Pluto's doorstep.  Given the vast scale of our Solar System, awaking on Pluto's doorstep means the closest approach will be in July.

We will see amazing things, if we are patient.

"Not all those who wander are lost"

Wanderers - a short film by Erik Wernquist.

A CGI video, with narration written and spoken by the late Carl Sagan.

Here is  a gallery of stills from the video.

I do not think we will get our meat bodies to these places anytime soon.  But if and when we do, it will be splendid.

Better Technology for Space Exploration

There are two kinds of technology that would make space exploration easier.

The first will come without government support. Anyone that figures out how to make a lighter solar cell, or how to deliver payload to earth orbit cheaper than their competition will do well without help in existing markets. If you can build a solar array that is lower mass for the same power, plenty of commercial ComSat companies will pay extra for that.

The second is more difficult.  There are technologies that NASA would really like to have: more powerful electric propulsion, or an Advanced Stirling Radioisotope Generator, but there is no current commercial market for these. Aerocapture beyond Earth orbit would also be good to have. It would be very valuable to have a rotating orbital habitat to simulate the term long effect of Lunar and Mars gravity on living terrestrial organisms like us.

We should spend more on advancing the second kind of technology.

And Now, For Our Next Trick...

So, we landed on a comet. What do we do for an encore?

Well, eventually we land on another comet, and do it even better.  But it will take time to figure out why what went wrong went wrong, and design and fund another mission, and get there. This will take years, but comets will still be there when we are ready to launch. We can, and must, and will be patient. We will play the long game. When we do it again it will be easier to do better because we will have learned in the interim.

In the meantime, I will quote the admirable Emily Lakdawalla, who did good service covering the Philae landing on twitter.

Coming up soon: Japan launches Hayabusa 2, an asteroid sample return mission, on November 30. New Horizons wakes up to begin encounter science for its Pluto flyby on December 6 (the flyby itself is next July). Dawn will get its first images of Ceres in February, and they'll already be better than Hubble's. Curiosity is doing the kind of science it was intended to do for only the third time on its mission, at a spot called Pahrump Hills in Gale crater. Opportunity is very close to the peak of the mountainous crater rim it's been climbing for a couple of years. Cassini has been on a high-inclination orbit at Saturn for a long time, but will soon be switching into an equatorial orbit that means lots more views and close flybys of Saturn's mid-sized icy moons. There's a lot going on!! But some sad things are coming -- both MESSENGER at Mercury and Venus Express at Venus are expected to crash into their respective planets within the next few months, ending those long missions (they've both nearly run out of maneuvering fuel).

Less immediately, in 2016 Juno arrives at Jupiter. And OSIRIS-REx launches, also intended to visit an asteroid and bring back samples.

We launch, and launch again. It's a great life, if you don't weaken.

These are the days of miracle and wonder...

Comets Are Weird

So this week, humans landed a robot on a comet. And when I say landed, I mean we bounced it off the comet twice, until it came to rest.

Philae was one of two robot spacecraft launched over ten years ago. Rosetta was the larger of the two, and still orbits Comet 67P.

Philae bounced twice, and landed in a place that was mostly in shadow and so starved for solar  power  It continued to transmit data until only enough power was left from her batteries to put the craft in hibernation, and it uploaded quite a lot. Plucky robot.

It gave us images of the surface. The one above is the strangest landscape beyond Earth's surface I have seen to date.

But wait, there's more.

We have known for some time that the nucleus of the typical comet is mostly fluffy; typically about half the density of water. They have been described dirty snowballs or snowy dirt balls.

But wait! Some of the uploaded data already show a more complicated picture than we thought. One of Philae's experiments, MUPUS, was designed to hammer one of its sensors into the surface of the comet. The surface turned out to be much harder than expected, and apparently broke the probe.

Perhaps we should think of comets not simply as dirty snowballs, but dirty snowballs that a cosmic prankster dipped in water and then left at subzero temperature until the exterior was as hard as rock. Alternatively, this might be a condition peculiar to impact craters on comets, and Philae happened to fall into one. But Philae also bounced pretty hard at the first landing site.

Or one might think of the comet as a a deep space Mallomar, or in this case a chocolate dipped Peep: a hard crust around a fluffy interior. But the reality is probably still more complex than that, with all but the most recent crater floors dusted with ejecta from later impacts.

And  even the fluffy parts of the comet might include large chunks of less fluffy matter: dirt, rocks  or ice.

Update:  As of November 18, ESA scientists say the data received so far suggests 4-8 inches of dust over hard ice, and a fluffy porous interior below that.

Humans Continue to Play the Long Game in Space

Today, the European Space Agency successfully landed a robot spacecraft on a comet for the first time in human history. Well done! It was launched ten years ago.

It was intended to launch even longer ago, to a different comet in January of 2003. A 2002 launch failure of the intended launch vehicle required a change in plans.

This is how you do it: with patience!

Humans Prepare to Land a Robot on a Comet Shaped Like a Rubber Duck

Well, they are and it is. The pictures remind me of an Alp in space, because that's more or less what comets are. There's a lot of snow.

But, I read that the comet itself is quite dark, like a lump of coal.

These are the days of miracle and wonder.

Ansari and Orteig: The Hard Going to the Stars

On Friday, October 31, Spaceship Two, Virgin Galactic's suborbital manned rocket, broke up in flight, killing one pilot and seriously injuring the other, and providing another harsh reminder of the risks of space flight.  Following the loss of an Antares rocket on October 28, it was a bad week for the launch industry.

I'll repeat what several other people has have said this week: space is hard.  Getting to space requires harnessing enormous energies with very light hardware. The Space Shuttle high pressure fuel pumps
each produced about 71,000 hp, equal to 15 large diesel locomotives, yet they were not much bigger than an automobile engine. They had a power to weight ratio of over 100 hp/pound: .5 hp/pound is typical for an automobile engine.

Ed Kyle puts it well:

Modern rocketry is a frightening balancing act. To accelerate from a dead stop to more than seven times faster than a rifle bullet in a few minutes, an orbital launch vehicle must create, contain, and endure extreme pressures, temperatures, and forces. All it takes to trip up the process is one loose connection, one small piece of sand or rust, a bad bit of metal or insulation, a misplaced bit in a control program, or an unexpected vibration.

Suborbital is technically a lot easier. 2,500 mph is probably enough to reach space briefly on a suborbital flight, compared to about 18,000 for orbital. And six times the velocity requires 36 times the energy, and much better shielding on reentry.

SpaceShipOne had the enough volume and payload to carry three humans to at least 100 km in altitude.  SS1 was less than four metric tonnes, fully loaded. It was launched from the White Knight One carrier aircraft, probably similar in mass fueled but not including the SS1 payload.

The closest orbital comparison is the Soyuz launcher and manned spacecraft, over 300 metric tonnes fully fueled and capable of carrying three humans to orbit and back.  And that's for an expendable launcher, while SSI and WK1 were reusable except for the SS1 motor.

But. While suborbital space flight is technically a lot easier than orbital, its economics are far more challenging. Commercial satellites are so profitable that their owners are willing to pay tens of millions of dollars to get one launched. The most capable launchers can charge over $100 million for an orbital payload.

If Virgin Galactic fills six passenger seats on SS2 per flight at their announced price of $250,000, that's only $1.5 million. A brief suborbital flight measured in minutes is simply a lot less valuable than an orbital flight that can last as long as you have supplies for.

And building a reusable rocket plane capable of speeds in excess of Mach 2 is not a trivial task at all.

One that carries six passengers is even harder. SS1 had a theoretical capacity of only two passengers. The supersonic X-planes carried only a pilot.

Compare the Orteig prize to the Ansari X Prize.

The first offered a prize of $25,000 in 1919, worth about $340,000 in 2014, for "the first aviator of any Allied Country" to fly nonstop from New York to Paris, or vice versa. To win required an aircraft that could fly the required distance at about 100 mph. Lindbergh won, but there were several other entrants that could have won if history had been somewhat different. They included a Wright-Bellanca WB-2 and a Fokker C-2 Trimotor, both of which became successful commercial aircraft, although operating in an environment of subsidized mail transport.

Linbergh's plane was a unique variant designed for the stole purpose of winning the Orteig Prize, but still part of a successful family of Ryan monoplanes.

In contrast, when SpaceShipOne attempted the Ansari X Prize in 2004, there were no rivals remotely ready to fly,  Building a rocket-powered airframe that can fly to the edge of space at over twice the speed of sound and return safely is much, much harder than flying nonstop from New York to Paris.

When only one company has shown that they can fly a reusable rocket capable of carrying passengers into space, if that company blunders in building their operational vehicle, there's no one to provide an alternative.

Yes, there's XCOR and their Lynx spaceplane. I wish them well, but they haven't flown it yet.

I believe the people responsible for SpaceShip Two have made at least major mistakes. The first was in making a jump to a spaceplane twice the size of the one that one went to the Smithsonian, instead of following it with a SpaceShip 1.1 for further flight tests followed by operational flights.  The second is choosing and sticking to the immature technology of hybrid rocket motors.

I think it's fair to say that entrepreneurs like Branson are rather more prone to hubris than the  average mortal. But it's a mistake to think that NASA administrators are quite free of hubris: pre-Challenger estimates of Space Shuttle reliability and the decision to launch Challenger in 1986 would both seem to qualify.

And government space agencies have their own unique failure modes: particularly, making important technical decisions influenced by jobs at stake in key Congressional districts, or the non-US equivalent.

I believe that some version of SpaceShip Two can be made operational, perhaps with significant modifications, and be relatively safe by the standards of dangerous pursuits like climbing Everest. Unless the investors lose faith in the project.

But remember: space is hard.

We Lost a Rocket Last Night

We lost an Antares rocket and a Cygnus spacecraft, bound for ISS, last night. About twelve seconds off the pad something went wrong. There seems to have been rapid unscheduled disassembly at the aft end of the launcher, and then the rocket fell back to the ground and exploded.

Throwing hardware out of our gravity well is really, really hard, and this is a reminder. The energies required are immense, yet the builder is required to make the rocket as light as possible

But, we know this is hard. So the United States can also reach ISS with completely different hardware: SpaceX's Dragon spacecraft and Falcon launcher. Russia, the European Union and Japan all have their own spacecraft and launchers as well. Our bench strength is deep.

To watch the launch I stepped out on the patio with my phone to point the way to due south and my laptop to watch the launch until it climbed above the horizon. Space travel is still hard, but we do live in an age of marvels.