Crotchety spacecraft

By Phil Plait | June 1, 2012 10:44 am

I have creative friends.

Emily Lakdawalla is a scientist, science journalist, and tireless advocate for space exploration. She also does handcrafts, and recently asked me for my mailing address. Hmmm… I thought. This’ll be good.

And I was right! Here’s what she sent me:

How cool is that? It’s a satellite model made with plastic canvas. That’s a plastic mesh you can cut to size, then stitch yarn in and out of the holes to cover it. I did a live video chat with Emily when Phobos-GRUNT re-entered, and she lamented my not having a good model of a satellite to use for demos. So she made me this one. And look how she signed the letter! I hope you recognize the little guy in her doodle.

I (and many others) suggested she make more spacecraft this way, and she has; she wrote a post at the Planetary Society Blog about them. She’s also created both the patterns and kits for MESSENGER (currently orbiting Mercury) and Dawn (orbiting Vesta, soon to leave for Ceres) which you can buy at her Etsy store (called SpaceCraft, of course). She also has the pattern for the twin GRAIL spacecraft available for free.

I’ll add that Emily scolded me that this is not crochet since you don’t use a crochet hook. However, the title was too much fun to resist. By the time you read this I’ll be at SpaceFestIV; Emily will be there too. I hope she’ll forgive me.

But either way, I know have this awesome little model to use for the next time I do a live video chat. Thanks, Em!

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CATEGORIZED UNDER: Cool stuff, Geekery, Space

Video of the lunar far side from GRAIL/Ebb

By Phil Plait | February 3, 2012 10:49 am

This is so cool: NASA’s twin GRAIL spacecraft (now named Ebb and Flow) have cameras on board to take images of the lunar surface, and an animation has been put together of Ebb’s view of the Moon’s far side!

Pretty neat. I love the wide-angle view; the individual images were taken while Ebb was still over a thousand kilometers from the Moon. The huge circular feature you can see on the right 30 seconds into the video is Orientale Basin, an impact so huge it must’ve lit up the solar system a few billion years ago. That basin is nearly 1000 km (600 miles) across! See the LRO image below for a clearer view, and click it for more info.

I’m really looking forward to seeing what will be done with these cameras. As Principal Investigator Maria Zuber explains in the video, they were installed specifically for educational purposes, and kids all over America will get a chance to examine the data. I love this idea, since it means these children will be invested in the project itself, and remember it for their whole lives. It’s a fantastic idea.


Image credit: NASA/GSFC/Arizona State University

CATEGORIZED UNDER: Astronomy, Pretty pictures, Space

Google+ astronomy weekly roundup video now online

By Phil Plait | January 6, 2012 9:00 am

Yesterday, I was in a live video chat session with several other scientists and science journalists. I wrote up the details of it yesterday, and it went pretty well! We had a lot of fun talking about the new GRAIL Moon mission, the fiery future return of Phobos-Grunt, 2012, and of course President Obama’s purported teleportation trip to Mars many years ago.

Wait, what?

Well, if you wanna know more, now you can: the video’s online.

The plan is to do these every week on Thursdays, and have a rotating cast of characters over time. I hope you like it. And I strongly suggest people join up over at Google+. I really like it there, and post quite a few things you won’t see here or on Twitter.

CATEGORIZED UNDER: Astronomy, Cool stuff, NASA, Science

NASA sends GRAIL shaped beacon to the Moon

By Phil Plait | January 1, 2012 3:14 pm

Mynd you, Møøn bites Kan be pretti nasti…

Today, NASA successfully put a new mission into lunar orbit: GRAIL, for Gravity Recovery and Interior Laboratory. Great acronym, weird name, right? What this mission will do is map the gravity field of the Moon, and use that to probe the interior composition. The basic idea isn’t all that complicated: fly a probe around the Moon. If it goes above a region where the density is higher, there will be a slightly stronger gravitational pull, and the spacecraft will accelerate a bit. By carefully measuring the spacecraft position and velocity, you can make the lunar gravity map.

In detail, that’s a bit tougher! What NASA has done is launch two probes, GRAIL-A and GRAIL-B, that will fly in the same orbit, one behind the other*. They’ll stay in constant communication, sending radio pulses to each other. The timing of these pulses allows an extremely accurate determination of their separation: their distance will be known to an accuracy of about a micron: that’s a hundredth the width of a human hair, or the size of a red blood cell!

So how does that help? If one of the two probes speeds up or slows down, the radio signal timing will change, taking more or less time to get from one probe to the other. The amount of change is related to the force of gravity felt by the probe, and that in turn is related to the density of the material below. In practice, making a gravity map this way is extremely complex, but it’s been done before here at Earth using probes like GRACE and GOCE. It’s tried and true.

Read More

CATEGORIZED UNDER: Cool stuff, NASA, Science, Space
MORE ABOUT: GRAIL, gravity, Moon

The naming of names

By Phil Plait | October 15, 2011 7:17 am

If you don’t like the way NASA and astronomers name their missions, then now’s your chance.

NASA is asking students to help them name the twin GRAIL satellites, currently on their way to the Moon. They want input from K-12 students, and they’re hoping this helps motivate kids to be interested in space. They don’t have suggestions, but I might urge you to think of either famous twins, of course, or maybe two people who helped explore the Moon, partners in some way (married couples, or two people who worked closely together). I don’t think they’ll allow the names of people still alive (so Neil and Buzz are out, unfortunately), but I’m guessing someone will come up with something good.

The deadline for that is November 11.

Not only that, but astronomers want to rename the Very Large Array, a collection of 27 separate 25-meter radio telescopes observing the skies from New Mexico. The array has been operational for decades, but has undergone recent extensive renovations, and the National Radio Astronomy Observatory thinks it’s appropriate to rename the array in honor of this.

If you’ve seen the movie "Contact" then you’ve seen the VLA; it’s where The Signal is first heard, the scene where Ellie is listening in using headphones. So I went to the Name The Array webpage and, deciding to keep the same initials, entered "Vega Loves Arroway". You may feel free to submit something better.

The deadline for renaming the VLA is midnight Eastern (US) time December 1.


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CATEGORIZED UNDER: Astronomy, Cool stuff, Humor, NASA

GRAIL on its way to the Moon!

By Phil Plait | September 10, 2011 10:30 am

This morning at 13:08:53 UT (09:08:53 Eastern US time) NASA successfully launched GRAIL, its latest mission to the Moon! This was the third launch attempt, after high winds scrubbed the first try, and the second was postponed to check out some system issues.

GRAIL is actually two spacecraft which will fly in tandem around the Moon, mapping its gravitational field and using that to probe its interior. A camera on board the rocket got footage of the spacecraft separating:

Nifty. As usual, Emily has some more info, and you should subscribe to her blog for updates. Heck, you should be reading it anyway.

My congratulations to NASA and the entire planetary scientist community!


GRAIL to try to launch again tomorrow

By Phil Plait | September 8, 2011 6:00 pm

[UPDATE: The launch of GRAIL has been postponed once again to Saturday, tomorrow. There are two launch windows; one at 12:29:45 UT and the other at 13:08:52 (08:29 and 09:08 Eastern US time). The weather forecast is iffy, so there may be another postponement. Stay tuned.]

NASA’s GRAIL mission — Gravity Recovery and Interior Laboratory, that is — was supposed to launch on September 8, but winds prevented takeoff. They will try again Friday (tomorrow) at 12:33:25 UTC (08:33:25 Eastern). Failing that, another launch window will be at 13:12:31 UTC (and lasts for only one second!). There are many more opportunities to launch until October 19, so I suspect NASA will play it safe. Emily Lakdawalla, as usual, has details.

GRAIL will head to the Moon, and is actually two separate spacecraft, each about a meter on a side. They will fly in formation, and use a suite of very sensitive detectors to essentially determine their distance from each other. The Moon is lumpy in its interior; in other words its density varies on the inside. This means an orbiting object will feel a slightly different pull of gravity with time as it circles the Moon. That change in gravity will change the orbital speed and therefore the distance between the two probes. They will be able to measure their separation to an accuracy of just a few microns… for comparison, a human hair is roughly 50 microns thick!

This will allow scientists to measure the interior distribution of mass inside the Moon, essentially probing its interior. The spacecraft also have cameras to take pictures of the Moon’s surface that will be available for schoolchildren, a project I think is very cool. But it’ll be a while: it will take a few months for the spacecraft to make their way into lunar orbit. They’re taking the scenic route, which saves fuel and allows a thorough checkout of the spacecraft.

You can watch the launch live on NASA TV.


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