Monday, December 08, 2014

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.


Wednesday, December 03, 2014

Interstellar

It was excellent, but flawed. I was glad I saw it in a theatre, in IMAX.

It was one of a small class of excellent science fiction movies where the science is important to the story and mostly actual science.

Mostly.

It repeatedly pays tribute to 2001: A Space Odyssey, one of the few films in the same category. But in 2001 the first and last parts of the movie are about alien science so advanced that they are, for us, indistinguishable from magic. And for the last, so incomprehensible that you can't understand what's going on without buying the book.

The middle third of 2001 does not violate science, except when it does. The moonbus follows a very  unlikely trajectory because that is easier to film.  If such a craft existed, it would have been launched in a ballistic trajectory from launch to destination, with no effort to maintain constant altitude.

According to the book, it was a surface vehicle, with very limited ability to launch over obstacles. Also not easy to film.

Discovery had no radiators because the director thought the audience would mistake them for wings.

Doing good cinema and good science at the same time is hard. I count Contact in this select group, but still  its wormhole opening technology was close to magic.

My biggest complaint about Interstellar is that at times it was hard to understand important words spoken.

There are some plot holes, but fewer than some people think. The ice that astronauts walk on on the second planet is probably unreasonably strong. Keeping the secret space program secret would be difficult if all the launches came from the base used for the final launch, but perhaps there were other, more remote launch sites.

Some have complained that if the Ranger spacecraft can reach orbit with a single reusable stage, why do they need a big two stage chemical rocket to get it into Earth orbit?

It seems that according to the film's site, the landers use both chemical and plasma rockets, and NASA has fusion reactors as a power source. If the reactor uses He-3, the limited supply would explain the two stage chemical rocket to reach Earth orbit.

Mapping Science Fiction in Three Dimensions

I think it is helpful to think of mapping Science Fiction in three dimensions.

The first is science truth. At one extreme, all of the science agrees with we now know about science, and no science is violated in the telling of the story. This hardly ever happens in Science Fiction movies, except in science docudramas, like Apollo13, or The Right Stuff. Which you should watch if you haven't yet done so.

Even the hardest of Science Fiction cinema almost always contains some dramatic license.

At the middle of the range, there's speculation about science that isn't obviously impossible, and if the story presents some speculation as fact, the story respects the logical conclusions from the speculation.

At the other extreme, the story completely contradicts what we actually think we know about our universe. For example, the story proposes that all of Earth's plant life is extinct, except in greenhouses in space.  Just outside the orbit of Saturn.  Yes, Silent Running, I'm looking at you. Or yarns in which radioactivity creates giant ants or web-slinging superheroes.

The second dimension is science relevance. If the story assumes that science will somehow allow us to make artificial people and that has an important impact on the narrative, that's one end of the scale. For example, Bladerunner.

If science allows us to make blasters that are remarkably similar to modern firearms except for the pewpewpew and the bright bolts of light, that's the other.

The third is narrative quality. Is it a good story, or not?

Sticking to movies, you can have a film that is excellent at science truth and science relevance, but mediocre at narrative, such as 2010: a Space Odyssey.

Or the reverse, such as the first two Star Wars movies.

You can also have a movie in which the science truth has gone stale with time, like Destination Moon.

A strong enough narrative can carry a story with poor science truth and science relevance. A Scanner Darkly is essentially a story about 1970s drug culture with some very speculative Science Fiction chrome bolted on. It's still a good movie.

Monday, December 01, 2014

My Pitch for a Buck Rogers Remake

Buck Rogers is put into suspended animation after being overcome by a mysterious gas while exploring a mineshaft/being frozen after crashing on a glacier/mumblemumble. He awakens in the 25th century to discover a world just beginning to claw its way back to advanced civilization after the centuries of barbarism that followed the collapse of society after the SpamBot Wars.

Little has survived from the old civilization, and much of it irrelevant to recreating modern technology. Among the most treasured of the Historical Documents is a series of illustrated texts that show the technology of the the 20th century: rockets with tail fins, analog gauges and vacuum tube electronics, rocket belts, leather flying helmets, and so on.

The engineers of the reborn civilization use the Historical Documents to recreate the technology of the past, tail fins and all. They quickly discover that single stage spaceships could not achieve interplanetary travel, or the flying belts the performance shown in the texts, through chemical rocket power alone. They deduce that the rockets were used only for maneuvering and rapid acceleration: the ancients must have had some other form of of primary propulsion!

This spurs them on to the research that accomplishes what they believe be the rediscovery of the Reactionless Drive. (Like the most practical form of artificial gravity it's something of a misnomer, but the important thing is that you don't need to carry reaction mass on board. Newton is not dissed.)

Dieselpunk hijinks ensue.

No Twiki.


Sunday, November 30, 2014

"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.

Friday, November 21, 2014

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.




Tuesday, November 18, 2014

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...

Saturday, November 15, 2014

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.

Wednesday, November 12, 2014

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!

Tuesday, November 11, 2014

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.