Bad Astronomy
The entire universe in blog form

May 5 2015 12:41 PM

Pluto: Looking Sharp

Last week, I (and everyone else) was wowed by new images from the New Horizons probe, which could see surface features on Pluto even though it was sill more than 100 million kilometers from its goal.

There was a press release about them before the images were revealed, and that had me scratching my head. I knew that from that distance, Pluto would only be a few pixels across. What could they have seen? Because Pluto would be so small, my first guess was they discovered a new moon.


But it turns out that Pluto looked far bigger in the images than I expected; 10 pixels across instead of just over four. How was that possible?

It was due to two things: superresolution and deconvolution. I wrote up an explanation of these techniques for my biweekly column on Note: The blog is subscription only, but with that you get access to a ton of other blogs. Also note that the news, images, and videos are all free.

I have a public talk I just put together on Pluto and New Horizons, and I already have to update it. I guess I’d better get used to that between now and close encounter on July 14! And probably for months after, too …

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May 5 2015 7:00 AM

SpaceX Will Test Its Launch Abort System Wednesday

If you want to launch astronauts in space, you have to make sure the procedure is as safe as possible. That’s why, for any launch system, NASA requires an abort procedure: a way to get the astronauts away from the rocket as quickly as possible if something goes wrong.

SpaceX is working on getting its Dragon capsule crew-rated, so it needs an abort system. A recent upgrade includes eight SuperDraco engines, set in pairs around its base. The idea is that if something catastrophic were to happen to the Falcon 9 rocket, the SuperDracos will fire to fling the capsule away.


They will put the engines to the test on Wednesday for a “pad abort test.” The Dragon will sit atop a truss to mimic the launch conditions on a Falcon 9 rocket. During the test, they’ll fire with 15,000 pounds of thrust each,* flinging the capsule about 1,600 meters up and over the Atlantic, where it will parachute down. The capsule is loaded with sensors, including a human test dummy (which they named “Buster,” an obvious homage to the dummy from MythBusters). Update, May 5, 2015 at 14:30 UTC: I heard the dummy's name from several sources, but now SpaceX has sent out a press release, and included on it is the claim that the dummy's name is not Buster ("There will be a dummy on board the spacecraft, but despite popular belief, his name is not Buster. Buster the Dummy already works for a great show you may have heard of called MythBusters. Our dummy prefers to remain anonymous for the time being.") I will have more on Bustergate as it develops.

You can watch live on NASA TV, NASA’s UStream channel, and (I suspect) the SpaceX livestream. The window for this opens at 11:00 UTC (07:00 Eastern U.S. time) and lasts until 18:30 UTC.

This is a necessary (and needed) step to complete on the way back to space for American astronauts. As I mentioned recently, we’re in a gap in our ability to launch Americans from American soil, but it’s really no longer than the one from Apollo to the Space Shuttle. And it’ll end very soon. SpaceX is making great strides, as is Blue Origin (though I want to iterate, again, my displeasure with NASA’s Space Launch System). I expect that by the end of 2017 we’ll see a very different landscape in crewed space exploration.

*I tend to use metric for measurements, but NASA and its contractors still report thrust in pounds. The metric unit is Newtons, which is basically unknown outside of engineering or physics and the like. But in case you care, each SuperDraco will generate roughly 70,000 Newtons.

As a bonus, under more normal circumstances, the engines can be used for maneuvering the capsule when it’s in space. The SuperDraco engine chamber is 3-D printed, more technically called metal laser sintering. I saw a bit of that process when I visited the SpaceX factory, and it was pretty cool. 

May 4 2015 12:58 PM

Moments Before the Crash

On April 14, 2015, SpaceX launched a Falcon 9 rocket with supplies for the astronauts on the International Space Station (this was before the more recent loss of the Russian Progress capsule).

After its primary job of lofting the upper stage and Dragon capsule high above the Atlantic was done, SpaceX attempted to land the first stage booster on a floating barge. Like the first attempt in January, this one didn’t go so well; it came in with too much sideways velocity, tipped, and hard-landed on the barge, exploding.


What did that look like from the barge, just a second or so before impact? This:

rocket landing
About two seconds later things got a lot harder to see.

Photo by Ben Cooper/SpaceX

That photo was taken using a remote camera on the barge, placed there by photographer Ben Cooper. The top of the booster is just off the top of the photo, and to give you a sense of scale, it’s 50 meters tall—roughly as tall as a 15 story building.

You can see the landing legs deployed at the bottom, and the flame of the exhaust as it tries to land. At the top you can just see parts of the fins that help steer it, and on the top right the plume of a steering jet, trying in vain to keep the booster upright.

It didn’t quite make it.

The next barge landing attempt will be for the next ISS resupply mission, CRS-7, currently scheduled for June 19. Hopefully third time’s a charm.

Correction, May 4, 2015, at 18:00 UTC: I originally misstated that the booster is 38 meters tall, but it turns out that's for the old v1.0 booster. The v1.1 is 50 meters tall.

May 4 2015 11:30 AM

Bad Astronomy Video: Megatons Away From Ordinary

The Sun is hot.

Yeah, I know, duh. It’s literally white-hot; glowing at a temperature of more than 5,500° Celsius. But it’s hotter than that: Its whisper-thin atmosphere, the corona, is actually far, far hotter, seething and writhing at more than 2 million degrees!


How does it stay that hot? After a long search spanning decades, astronomers think they’ve found the Sun’s heat engine: nanoflares. Find out how they work in this week’s Bad Astronomy Video.

Even though I’ve been an astronomer nearly all my life, and deal with huge numbers all the time, every now and again I have to back out of my own head a little and chuckle.

Only astronomers would refer to millions of explosions every second, each equal to detonating tens of millions of tons of TNT, using the prefix “nano.”

May 4 2015 7:15 AM

Fantasy on a Martian Theme

I sometimes wonder what it would be like to stand on the surface of Mars, another world, peering out over an alien landscape. In my mind, my limited knowledge of the scientific reality of such a view wars with the more vibrant images of imagination, producing a compromise that is somehow better than both.

When I close my eyes, and try really hard, it looks something like this:

May 3 2015 7:30 AM

Waxing Crescent Ceres

Apropos of nothing, please enjoy this lovely mosaic of the asteroid Ceres, created from a series of images taken by the Dawn spacecraft from April 24–26, 2015:

Ceres. Wow.


Yowza. That’s a big beautiful icy rock.


On the April 23, Dawn entered its science orbit, settling down after its long approach to Ceres. It’s in a circular polar orbit at a height of 13,500 kilometers over the surface. It takes about two weeks to circle the asteroid once.

Do you have red/green glasses? Try this 3-D anaglyph of Ceres, too. It really makes that double impact crater in the middle pop.

I’m very curious to see high-resolution images of the bright spots in the big crater we’ve been seeing, especially over time. There are hints that the two spots are actually several blurred together, so it’ll be very interesting to see what they look like. A friend pointed out to me that they’re not as bright as you might think; it’s just that Ceres is really dark. It reflects, on average, about 9 percent of the light that falls on it. Dawn’s other target, the asteroid Vesta, has a reflectivity of more like 43 percent!

Anyway, we’ll learn more over time as scientists get a chance to analyze the new hi-res data. It’s nice to see a mission just getting started with a new target even as MESSENGER ends its life on Mercury. Hopefully, the White House and Congress will fund more planetary missions; right now there aren’t any big ones being planned or built. Wouldn’t it be nice to see some Cassini-class missions orbiting a half-dozen outer solar system bodies? 

May 2 2015 9:51 AM

Crash Course Astronomy: Mars

I’m pretty sure I’ve seen every single science-fiction movie made about Mars. Angry Red Planet, John Carter, Mars Attacks!, and the best of them all, War of the Worlds (the George Pal 1953 version, duh).

But sometimes, truth is cooler than fiction. The planet Mars may not have wild Victorian civilizations with any princesses named Dejah Thoris, but it has a lot of other amazing features. And the best part? It’s fact, not fiction.


So explore Mars with me in this week’s episode of Crash Course Astronomy: Mars.

Unfortunately, Mars is on the other side of the Sun from us, close enough in the sky that it sets about an hour after the Sun does. That makes it really hard to see, and it won’t be up high enough to spot in the morning before sunrise until later in the summer. But if you want to find more, you can search my blog for posts about the Curiosity rover, and the HiRISE camera on the Mars Reconnaissance Orbiter, and just about Mars itself.

I suspect that’ll be enough to keep you reading until the Red Planet is visible once again.  

May 1 2015 7:15 AM

Blue Origin Makes a Surprise Rocket Launch

I’m a big fan of commercial space—private companies building rockets to get into space. I write about SpaceX a lot, of course, since it is very public about its progress. I don’t write as much about Blue Origin, run by Amazon’s Jeff Bezos, because it’s more secretive, keeping things very close to the vest.

So I was caught a bit off-guard Thursday when the company announced that it had performed a test flight of its suborbital New Shepard rocket! The video is very impressive:


On Wednesday, the rocket lifted an uncrewed test capsule to a height of 93.5 kilometers. The capsule, which is designed to hold up to three passengers, separated cleanly from the vehicle, and landed under three parachutes safely on the West Texas ground.

The rocket itself is designed to land vertically, slowing under thrust and settling down on deployable landing legs. This part of the test didn’t perform so well; the hydraulics for the legs didn’t work, and it presumably crashed. This is similar to the problem SpaceX had with its first attempted landing of the Falcon 9 booster in January.

trajectory of the rocket
The sub-orbital trajectory and steps of the New Shepard flight. Click to parabolenate.

Drawing by Blue Origin

This is pretty amazing news, and very welcome. The plan is that Blue Origin will offer seats on its capsule in two years, selling tickets for suborbital flights—that is, straight up and down (or, more accurately, a ballistic arc), not going around the Earth as in orbital flight. It eventually plans to build rockets capable of achieving orbit.

The current engine it has designed, the BE-3, uses liquid oxygen and hydrogen and has 110,000 pounds of thrust. It is already working on the BE-4, which will produce 550,000 pounds. That upgraded version will be for its next-generation rocket, Very Big Brother, which will be used to go into orbit. The company expects that to be flight-ready in 2017, and it also has a contract with United Launch alliance to provide the BE-4 engines for the new ULA Vulcan rocket.

I’ll note this test flight didn’t quite reach space, technically. That is (somewhat arbitrarily) designated as 100 km above sea level and is called the Kármán line. But I think getting 93.5 percent of the way is still pretty danged impressive.

These are exciting times for space exploration. Although the U.S. doesn’t have the capability to launch Americans into orbit from American soil, that day is fast approaching. The gap we’re in right now is comparable to the amount of time between the end of the Apollo program and the first Space Shuttle launch. The difference now is that instead of relying on a single (and arguably over complex) launch vehicle, we’ll soon have several to choose from, and they’ll be far less expensive than the Shuttle.

It is my fervent hope that in 10 years we’ll be looking back at this crewed launch gap as a very small stumble on the way to space. And that the number displayed here will also be headed skyward.

April 30 2015 5:56 PM

NASA Chief Statement on House Budget Bill

As I wrote this morning, Republicans on the House Committee for Science, Space, and Technology passed a nakedly partisan budget authorization bill for NASA that drastically and brutally slashes hundreds of millions of dollars from NASA's Earth Science Division, which studies how climate change is affecting our planet.

Charles Bolden, NASA administrator, issued a statement that is brief, to the point, and clearly states his feelings.

The NASA authorization bill making its way through the House of Representatives guts our Earth science program and threatens to set back generations worth of progress in better understanding our changing climate, and our ability to prepare for and respond to earthquakes, droughts, and storm events.   
NASA leads the world in the exploration of and study of planets, and none is more important than the one on which we live.
In addition, the bill underfunds the critical space technologies that the nation will need to lead in space, including on our journey to Mars.

If I were him, I would've laced that with some colorful metaphors, too.

April 30 2015 10:00 AM

Farewell, Good MESSENGER

Today, sometime around 19:30 UTC (3:30 p.m. Eastern U.S. time), the MESSENGER spacecraft will slam into the planet Mercury at nearly four kilometers per second.

That will bring to an end an astonishingly successful mission, one that was ridiculously difficult to pull off.


Getting a probe to Mercury is hard. Mercury orbits the Sun far faster than Earth does, but, ironically, dropping the probe straight down from Earth would accelerate it too much to achieve orbit. On its way to the inner solar system, MESSENGER had to pass by Earth once, Venus twice, and Mercury three times to match velocities.

And now, after six and a half years on route, and four years circling the planet (totaling more than 4,000 complete orbits), MESSENGER is out of fuel. The gravity of the Sun distorts its orbit, and over time it would crash one way or the other. Scientists and engineers squeezed every last drop of science they could out of the probe, but the time has come. Today it becomes a part of the planet it studied for so long.

MESSENGER impact site
The projected trajectory and impact site on Mercury; this is on the far side, so it will happen out of sight of Earth.

Photo by NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

And what a mission it had! The MErcury Surface, Space ENvironment, GEochemistry, and Ranging spacecraft achieved so much in its short time around the rocky world. It made the first global map of Mercury, found ice in the poles, sampled its exosphere, discovered why the planet is so dark (it’s painted black by passing comets), found volcanic deposits, and mapped the minerals on the surface.

You can read more in the Related Posts section below, and see what the principal investigator thought were its 10 greatest highlights. The University of Michigan College of Engineering put up a nice little list of facts about it, too.

NASA released a fitting tribute video to the mission. Watch:

It should be noted that the European Space Agency is preparing its own Mercury mission, due to launch in early 2017. But MESSENGER was special; it was the first Mercury orbiter.

There have been so many nights I’ve gone out after sunset and spotted Mercury in the west, hanging over the horizon in the twilight glow. It’s not always easy to see, and there’s some satisfaction in spotting it before the sky is dark.

Right now, Mercury is climbing in the sky again after sunset, and tonight will be very close to the Pleiades, low to the west. Look for it with binoculars but have a care, it’s low. By the time the sky is dark, it’ll be gone.

Mercury and Venus
Venus (top) and Mercury (middle) as seen from my backyard after sunset on Jan. 6, 2015.

But if you do catch Mercury, a faint spark in the gloam, take a moment and tip your hat to MESSENGER, a human sentinel that watched over the tiny, broiling, spectacular, and now less-unknown world.

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