Tempel Encounter

As mentioned previously, NASA’s Stardust spacecraft completed its journey and close approach of comet Tempel 1.

Tempel imaged from Stardust-NExT

NASA's Stardust-NExT mission took this image of comet Tempel 1 at 8:39 p.m. PST on Feb 14, 2011. - Click for full-sized version - Credit: NASA/JPL-Caltech/Cornell

As Stardust approached Tempel 1, it began snapping images;61 out of the 72 have been released at this point. After passing its point of closest approach, it turned to face the comet to image the comet as it shrinks back into the distance.

I had thought it would make be interesting to take the images and string them together into an animation, but before I had a chance I found the following one that was excellently done by Emily Lakdawalla at The Planetary Society Blog:

Animation of Tempel 1 by Emily Lakdawalla

This animation consists of 61 images of Tempel 1 taken by Stardust during its flyby on February 15, 2011. The images have been rotated 180 degrees (so that illumination appears to be coming from above) and aligned. Credit: NASA / JPL / Cornell / animation by Emily Lakdawalla

The Planetary Blog has a bunch of great information on the Tempel 1 encounter, and so much more; I recommend reading it on a regular basis.

So, what about that impact crater made by Deep Impact in 2005? Well, that crater is visible and recognized in some of the images that Stardust grabbed. You can check out this page to view some before-and-after images as well as other highlights of the recent fly-by. To my untrained eye, I even have a hard time noticing it when it’s pointed out to me. I’m sure skilled observers see a lot more than myself and further data will be used to better represent what we’ve learned from these new images.

Mission managers have called Stardust-NExT (New Exploration of comet Tempel) a 100% success, and for now, Stardust sails off on its orbit. I anxiously await to see what it might be called upon to do next!

How NASA Celebrates Valentine's Day

Many people on Earth take St. Valentine’s Day to celebrate the love they share with the special someones in their lives. It’s a day of roses by the dozens, chocolates in heart-shaped boxes, and sweet little love notes.

NASA will be marking February 14 a little differently, by revisiting an old friend whom NASA last left on less-than-amicable terms.

But first, a little history on a couple of previous NASA missions that make this third one possible.

So, Stardust was launched just over 12 years ago, on February 7, 1999. Its duty was to investigate the composition Comet Wild 2 and its coma (the nebulous arrangement of material surrounding a comet’s nucleus). After traveling back to Earth, Stardust dropped a capsule, containing material collected from Wild 2, down to Earth. It became the first sample return mission to sample and return cosmic dust to Earth. After 3 billion miles of travel, a visit to within miles of comet Wild 2, and a return of cosmic samples, Stardust could retire peacefully knowing it had accomplished its mission. NASA, wasn’t done with Stardust yet, however…

Stardust Capsule

NASA's Stardust sample return capsule successfully landed at the U.S. Air Force Utah Test and Training Range at 2:10 a.m. Pacific time (3:10 a.m. Mountain time). The capsule contains cometary and interstellar samples gathered by the Stardust spacecraft. / Source: NASA

Deep Impact:
The second mission that adds to this story is Deep Impact, which was launched in 2005. Its primary mission was to analyze the composition of 9P/Tempel, by releasing an impactor to smash into the comet, and then analyze the debris kicked up.
High Resolution Instrument, Visual CCD (HRIV) during encounter

High Resolution Instrument, Visual CCD (HRIV) during encounter / Source: NASA / Click for bigger version.

On July 2005, the impact was a success, and added to our understanding of comets, their origins, and was further proof that NASA can successfully undertake significantly ambitious projects. That being said, the impact created a very bright dust cloud which made observations of the impact crater difficult to impossible.

Now, back to Valentine’s Day:
After Stardust’s return to Earth and release of the samples capsule, NASA had to decide what to do, if anything, with Stardust. In 2007, they decided to maneuver Stardust over to Tempel for a second chance at observing the impact crater Deep Impact left during its impactor mission. 4 years later, Stardust is nearly there and ready to report its findings. On Valentine’s Day, February 14 at 8:56pm (PST), Stardust will make its closest approach to Tempel and NASA will be providing a number of venues for coverage.

Beginning at 8:30pm (PST), NASA will be broadcasting coverage of the encounter on NASA TV as well as through their website. From the press release:

The coverage will include live commentary from mission control at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif., and video from Lockheed Martin Space System’s mission support area in Denver.

A news briefing is planned for 10 a.m. on Feb. 15. Scheduled participants are:
-Ed Weiler, NASA’s associate administrator, Science Mission Directorate
-Joe Veverka, Stardust-NExT principal investigator, Cornell University
-Tim Larson, Stardust-NExT project manager, JPL
-Don Brownlee, Stardust-NExT co-investigator, University of Washington, Seattle

In a way, the whole situation fits a Valentine’s theme (if not a dramatic made-for-TV movie). Exchange the spacecraft and Tempel for people, and you’ve got instant drama. “After a break-up that left their relationship in ruins, they reunite in a surprise encounter on Valentine’s Day”. (Okay, so maybe I’m being a little too imaginative, and in this case it’s a different craft visiting Tempel… and umm, I’m not sure how taking pictures fits the storyline…)

Luckily, space science is exciting and interesting enough that I don’t need to try to enhance it with personification and drama. I just need to tell you when to watch!

Gather the family and enjoy the coverage. Happy Valentine’s Day.

Pac-Man On Mimas

Saturn’s icy moon, Mimas, has long been remarked for its large Herschel Crater giving it the appearance of the Death Star, the fictional space station of Star Wars fame.


Death-Star-esque Mimas, imaged by Cassini — Click for high-resolution view

Perhaps Mimas inspired George Lucas when creating the Death Star? Nope; Voyager was the first to give us close-up views of Mimas, a few years after ‘A New Hope’ was in theatres.

But earlier this year, Mimas revealed another uncanny secret resemblance to something out of recent pop-culture history: Pac-Man!

Mimas Temperature Map

Mimas Temperature Map – Click for a Pac-tastic Larger Version

So what we’re seeing here is a map of temperature differences placed over a visual-light image of Mimas. If you think it’s curious that the highest temperatures seem to vary in such a way, you’re not alone:

“Even though we can’t explain the observed pattern of surface temperatures on Mimas, the giant Herschel crater is a leading suspect[.]” “The energy of impact that created it several billion years ago has been estimated to be one-seventh of Mimas’s own gravitational energy. Anything much larger would likely have torn the moon apart. We really would like to see if there is also an anomalous temperature pattern on the other side of Herschel, which has not been observed so closely.” – Dr. Mike Flasar, composite infrared spectrometer principal investigator from NASA Goddard Space Flight Center.

The following image gives an idea of how what’s actually occurring on Mimas compared to what would previously be expected:

Comparison of different images of Mimas.

Comparison between expected temperature-map, actual temperature-map, visual light, and actual temperature-map layered on visual light images. – Click for full version.

A leading theory is that different textures of surface materials (mostly water ice with small amounts of rock) are holding on to heat from the Sun differently, but what is still not understood is why such sharp boundaries exist between these textures — giving the Pac-Man shape. It’s possible that the impact that caused the Herschel Crater distributed the more heat-absorbent materials in that pattern, but Mimas is constantly bombarded by impacts (as can be clearly seen when viewing the high resolution image of Mimas above), which you’d expect to destroy long ago any non-uniform surface make-up.

So for now, no definite answer is available. Luckily, we have the amazing Cassini orbiter up there, collecting more data for the scientists to work with.

Akatsuki Fails Venus Orbit Attempt – Oh Well, We'll Try Again… In Six Years

Akatsuki - Planet-C

Planet-C Akatsuki | Image credit: Akihiro Ikeshita and JAXA

JAXA’s (Japan Aerospace Exploration Agency) third planetary explorer, Planet C (Akatsuki), failed to enter Venus’ orbit following a journey that lifted off in May of this year.

According to JAXA:

The Institute of Space and Astronautical Science of the Japan Aerospace Exploration Agency (ISAS/JAXA) performed Venus orbit insertion maneuver (VOI-1) for the Venus Climate Orbiter “AKATSUKI” at 8:49 a.m. on December 7 (Japan Standard Time,) but, unfortunately, we have found that the orbiter was not injected into the planned orbit as a result of orbit estimation.

JAXA has set up an investigation team to try and understand why the orbit insertion failed. While control has been reestablished, “the spacecraft is functioning but has put itself in a standby mode with its solar panels facing towards the Sun. It is also spinning slowly — about every 10 minutes — and radio contact is possible only for 40 seconds at a time.

If control is able to be completely regained, there will be an opportunity to re-try entering Venusian orbit in six years — Akatsuki doesn’t have the fuel to hit the brakes and go back for another go at it.

This will mark the second JAXA planetary explorer that failed to complete its mission. Planet-B — dubbed “Nozomi” — failed to enter Mars orbit in 2003. That mission was abandoned, but the spacecraft is currently still active.

While the challenges of space travel have proven frustrating for JAXA, the agency cannot be said to not have its successes. Planet-A (“Suisei”) came within 151,000km of Halley’s Comet in 1986, as part of an international armada of probes sent to the renowned iceball during its last approach to our neck of the solar system.


Planet-A | Suisei



In addition to that, they have another very nifty, and successful, vehicle out there named IKAROS (“Interplanetary Kite-craft Accelerated by Radiation Of the Sun”). IKAROS is an experiment designed to demonstrate solar-sail technology as a means of traveling interplanetary space. IKAROS is an exciting little machine and I intend to devote an entire post to it in the near future.

Space exploration has come a long way in a very short amount of time, but we continually have these pesky failures to continually remind us that it is also very challenging. As frustrating as these complications may be, we can still appreciate the lessons learned and apply them to the success of future endeavors.

The Deathstar…. Err… Mimas

Cassini never ceases to amaze me.

Saturn has moons. Lots of moons (at least 62). And I find each one of those moons to be equally interesting.

Recently, the orbiter, Cassini, snapped the following photo of one of Saturn’s moons, Mimas.

(Click image to BIGGIFY)
Mimas is the twentieth largest moon in our solar system, yet is the smallest astronomical body that is believed to be round in shape due to its self-gravitation. Mimas has an interesting feature in a huge crater named Herschel. Compared to Mimas, this crater is huge. It is 80 miles (130km) wide, which is about a third of the total size of the moon itself (wider than Canada). As Phil Plait points out, the impact that created this crater was just about as big as it could have been without obliterating Mimas.

The results are beautiful. Some see the crater resembling a big eye. To many, including myself, it looks like the Deathstar:
(That’s no moon. It’s a space station. – Obi-Wan Kenobi)

For a mission that began in 1997, Cassini (Cassini-Huygens originally, until the Huygens probe was sent to land on the surface of Titan) just keeps on keepin’ on. It has had its missions and extended multiple times, and will most likely keep snapping these shots until it makes a flaming plunge into Saturn’s atmosphere in 2017. NASA, and its counterparts from around the globe, have done a fantastic job of completing their main missions, and then coming up with ways to continue using them for additional missions. We’re learning new and amazing things on a regular basis, and I think that’s just grand.