Posts Tagged ‘nasa’

Slice of History: Free Fall Capsule Drop Test

Thursday, August 2nd, 2012

By Julie Cooper

Each month in “Slice of History” we feature a historical photo from the JPL Archives. See more historical photos and explore the JPL Archives at https://beacon.jpl.nasa.gov/.

Free Fall Capsule Drop Test
Free Fall Capsule Drop Test — Photograph Number 354-595

In 1961, a drop capsule was developed at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., by Section 354, Engineering Research. It was an experimental chamber to study how liquids behave in free-fall (zero gravity). The prototype capsule was dropped from a helicopter hovering at 800 feet, but the capsule was found to be too unstable for these tests. In September 1962, a trial drop was done from the Bailey bridge that connected JPL to the east parking lot. Testing was then moved to a bridge crossing Glen Canyon near Page, Arizona. The dam was under construction at the time and provided a 672-foot-fall with a soft dirt impact area.

The 204 pound shell contained a high-impact sequence camera designed for this experiment, a stopwatch, a liquid sample and a release mechanism. Three external motion picture cameras with different focal lengths looked down on the capsule as it fell. Although the capsule fell for about 10 seconds without rolling, pitching or yawing, there were problems with the internal release mechanism. It appears the experiment was discontinued after two attempts.

This post was written for “Historical Photo of the Month,” a blog by Julie Cooper of JPL’s Library and Archives Group.


A Different Slant:

Monday, July 9th, 2012

By Duane Roth

Cassini Has a Special View of Saturn These Days - How Did It Get There?

For the past 18 months, NASA’s Cassini spacecraft has been orbiting Saturn in practically the same plane as the one that slices through the planet’s equator. Beginning with the Titan flyby on May 22, navigators started to tilt Cassini’s orbit in order to obtain a different view of the Saturnian system. The measure of the spacecraft orbit’s tilt relative to Saturn’s equator is referred to as its inclination. The recent Titan flyby raised Cassini’s inclination to nearly 16 degrees. Seven more Titan flybys will ultimately raise Cassini’s inclination to nearly 62 degrees by April 2013. On Earth, an orbit with a 62-degree inclination would pass as far north as Alaska and, at its southernmost point, skirt the latitude containing the tip of the Antarctic Peninsula.

These graphics show the orbits NASA's Cassini spacecraft has made and will make around the Saturn system from September 2010 to April 2013.These graphics show the orbits NASA’s Cassini spacecraft has made and will make around the Saturn system from September 2010 to April 2013. As shown in gray, Cassini orbited within the plane of Saturn’s equator during the first 18 months of its current mission phase, known as the Solstice mission. Then, starting in May 2012, Cassini used the gravity of Saturn’s largest moon, Titan, to tilt its orbit as shown in the magenta loops, reaching a maximum tilt of about 62 degrees in April, 2013. Titan’s orbit is shown in red. The orbits of Saturn’s inner moons are shown in black. Image credit: NASA/JPL-Caltech

You may wonder why this change has been planned and how this feat is achieved. The “why” is to allow scientists to observe Saturn and the rings from different geometries in order to obtain a more comprehensive three-dimensional understanding of the Saturnian system. For instance, because Saturn’s rings lie within Saturn’s equatorial plane, they appear as a thin line when viewed by Cassini in a near-zero-degree orbit inclination. From higher inclinations, however, Cassini can view the broad expanse of the rings, making out details within individual ringlets and helping to unlock the secrets of ring origin and formation. Some of those images have already started to come in.

At higher inclinations, Cassini can also obtain excellent views of Saturn’s poles, and measure Saturn’s atmosphere at higher latitudes via occultation observations, where radio signals, sunlight or starlight received after passing through the atmosphere help to determine its composition and density.

The “how” is by using the gravity of Titan — Saturn’s largest moon by far — to change the spacecraft’s trajectory. Like the rings and Cassini’s previous orbit, Titan revolves around Saturn within a plane very close to Saturn’s equatorial plane. As Cassini flies past Titan, Titan’s gravity bends the spacecraft’s path by pulling it towards the moon’s center — similar to a ball bearing rolling on a smooth horizontal surface past a magnet. Near Titan, the motion is confined to a plane containing the spacecraft’s path and Titan’s center of mass. If this “local” plane coincides with Cassini’s orbital plane about Saturn, the trajectory’s inclination will remain unchanged. However, if this plane differs from Cassini’s orbital plane about Saturn, then the bending from Titan’s gravity will have a component out of Cassini’s orbital plane with Saturn, and this will change the tilt of the spacecraft’s orbit. Repeated Titan flybys will raise Cassini’s orbit inclination to nearly 62 degrees by April of next year and then lower it back to the Saturn equatorial plane in March 2015.

This view, from the imaging camera of NASA's Cassini spacecraft, shows the outer A ring and the F ring of SaturnNASA’s Cassini spacecraft has recently resumed the kind of orbits that allow for spectacular views of Saturn’s rings. This view, from Cassini’s imaging camera, shows the outer A ring and the F ring. The wide gap in the image is the Encke gap, where you see not only the embedded moon Pan but also several kinky, dusty ringlets. A wavy pattern on the inner edge of the Encke gap downstream from Pan and a spiral pattern moving inwards from that edge show Pan’s gravitational influence. The narrow gap close to the outer edge is the Keeler gap. Image credit: NASA/JPL-Caltech/SSI

Gravity assists are key to Cassini’s ever-changing orbital geometries. Onboard propellant alone would quickly become depleted attempting to accomplish these same changes. A gravity assist can be characterized by the amount of “delta-v,” or change in the velocity vector, it imparts to a spacecraft. Delta-v may of course also be imparted to the spacecraft via rocket engines and, either way, alters the spacecraft’s orbit. The eight Titan gravity assists responsible for raising Cassini’s inclination to 62 degrees will provide a delta-v of 15,000 mph (6.6 kilometers per second). For comparison, Cassini’s rocket engines had only enough propellant after initially achieving orbit around Saturn to deliver about 2,700 mph (1.2 kilometers per second) of delta-v. That’s 15,000 mph of capability spread over 11 months via gravity assists versus a modest 2,700 mph of capability spread over more than 13 years via rocket engines! Because delta-v is a vector, it may change both the speed and direction of Cassini at a point along its orbit, so the speed of Cassini is not changing by 15,000 mph, but mostly all of the directional changes sum to 15,000 mph. To give these values some context, Cassini’s speed typically varies between as low as 2,500 mph (1.1 kilometers per second) and as high as 79,000 mph (35 kilometers per second) relative to Saturn between apokrone and perikrone, the farthest and closest points from Saturn along its orbit. Gravity assists from the initial prime mission Titan flyby in 2004 to the final Solstice Mission Titan flyby in 2017 will provide nearly 200,000 mph (90 kilometers per second) of delta-v, leveraging the onboard propellant by a ratio of 75 to 1. The bulk of the Saturn tour trajectory is shaped by gravity assists, while the role of onboard propellant is to fine-tune the trajectory.

At the end of year 2015, Cassini will again begin climbing out of Saturn’s equatorial plane in preparation for its grand finale. After reaching an inclination of nearly 64 degrees, a Titan gravity assist in April 2017 will change Cassini’s perikrone so that Cassini will pass through the narrow 2,000-mile (3,000-kilometer) gap between Saturn’s atmosphere and innermost ring. Twenty-two spectacular orbits later, one final distant Titan gravity assist will alter Cassini’s course for a fiery entry into Saturn’s atmosphere to end the mission.


Shedding Light on the Scarred Face of Asteroid Vesta

Thursday, July 5th, 2012

By Marc Rayman

As NASA’s Dawn spacecraft investigates its first target, the giant asteroid Vesta, Marc Rayman, Dawn’s chief engineer, shares a monthly update on the mission’s progress.

Image of the giant asteroid Vesta taken by NASA's Dawn spacecraft
This image, from NASA’s Dawn spacecraft, shows rock material that has moved across the surface and flowed into a low area in the ridged floor of the Rheasilvia basin on Vesta. The image shows how impacts and their aftermath constantly reshape the landscape. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI

Dear Upside Dawn Readers,

Dawn is now seeing Vesta in a new light. Once again the probe is diligently mapping the ancient protoplanet it has been orbiting for nearly a year. Circling the alien world about twice a day, the ardent adventurer is observing the signatures of Vesta’s tortured history, including the scars accumulated during more than 4.5 billion years in the main asteroid belt between Mars and Jupiter.

Having successfully completed its orbital raising maneuvers to ascend to its second high-altitude mapping orbit (HAMO2), Dawn looks down from about 680 kilometers (420 miles). This is the same height from which it mapped Vesta at the end of September and October 2011. The lifeless rocky landscape has not changed since then, but its appearance to the spacecraft’s sensors has. The first high-altitude mapping orbit (HAMO1) was conducted shortly after southern hemisphere summer began on Vesta, so the sun was well south of the equator. That left the high northern latitudes in the deep darkness of winter night. With its slower progression around the sun than Earth, seasons on Vesta last correspondingly longer. Thanks to Dawn’s capability to linger in orbit, rather than simply conduct a brief reconnaissance as it speeds by on its way to its next destination, the probe now can examine the surface with different lighting.

Much of the terrain that was hidden from the sun, and thus the camera, during HAMO1 is now illuminated. Even the scenery that was visible then is lit from a different angle now, so new observations will reveal many new details. In addition to the seasonal northward shift in the position of the sun, Dawn’s orbit is oriented differently in HAMO2, as described last month, so that makes the opportunity for new insights and discoveries even greater.

The strategy for mapping Vesta is the same in HAMO2 now as it was in HAMO1. Dawn’s orbital path takes it nearly over the north pole. (As we saw last month, the orbit does not go exactly over the poles but rather reaches to 86 degrees latitude. That slight difference is not important for this discussion.) During the ship’s southward passage over the sunlit side, the camera and the visible and infrared mapping spectrometer (VIR) acquire their precious data. After passing (almost) above the south pole, Dawn sails north over the night side. Instead of pointing its sensors at the deep black of the ground below, the probe aims its main antenna to the extremely distant Earth and radios its findings to the exquisitely sensitive receivers of the Deep Space Network. The pattern repeats as the indefatigable spacecraft completes loop after loop after loop around the gigantic asteroid every 12.3 hours.

As Dawn revolves, Vesta rotates on its axis beneath it, turning once every 5.3 hours. Just as in HAMO1, mission planners artfully choreographed this celestial pas de deux so that over the course of 10 orbits, lasting just over five days, the camera would be able to view nearly all of the lit surface. A set of 10 orbits is known to Dawn team members (and to you, loyal readers) as a mapping cycle.

Until a few months ago, HAMO2 was planned to be four cycles. Thanks to the determination in April that Dawn could extend its residence at Vesta and still meet its 2015 appointment with dwarf planet Ceres, HAMO2 has been increased to six mapping cycles (plus even a little more, as we shall see below), promising a yet greater scientific return.

In cycle 1, which began on June 23, the camera was pointed at the surface directly underneath the spacecraft. The same view will be obtained in cycle 6. In cycles 2 through 5, images are acquired at other angles, providing different perspectives on the complex and dramatic landscape. Scientists combine the pictures to formulate topographical maps, revealing Vesta’s full three-dimensional character from precipitous cliffs and towering peaks of enormous mountains to gently rolling plains and areas with mysterious ridges and grooves to vast troughs and craters punched deep into the crust. Knowing the elevations of the myriad features and the angles of slopes is essential to understanding the geological processes and forces that shaped this exotic mini-planet. In addition to the exceptional scientific value, the stereo imagery provides realistic, exciting views for anyone who wants to visualize this faraway world. If you have not traveled there yourself, be sure to visit the Image of the Day regularly and the video gallery occasionally to see what you and the rest of humankind had been missing during the two centuries of Vesta’s appearance being only that of a faint, tiny blob in the night sky.

› Continue reading Marc Rayman’s Dawn Journal


Dawn Goes Over ‘n’ Out

Monday, June 4th, 2012

By Marc Rayman

As NASA’s Dawn spacecraft investigates its first target, the giant asteroid Vesta, Marc Rayman, Dawn’s chief engineer, shares a monthly update on the mission’s progress.

Images of the giant asteroid Vesta taken by NASA's Dawn spacecraft in 2011 and 2012
On May 3, 2011, the mapping camera on NASA’s Dawn spacecraft captured its first image (left) of the giant asteroid Vesta. Only 5 pixels across, the image didn’t provide any new information about the asteroid, but it was important for navigation purposes and provided an exciting first look at Dawn’s eventual target. About five months later, Dawn snapped the much more detailed image on the right from only 700 kilometers (435 miles) from the surface of Vesta and has since provided unparalleled views of the mysterious world. Image credit: NASA/JPL-Caltech

Dear Readers of all Dawnominations,

Far from Earth, on the opposite side of the sun, deep in the asteroid belt, Dawn is gradually spiraling around the giant protoplanet Vesta. Under the gentle pressure of its uniquely efficient ion propulsion system, the explorer is scaling the gravitational mountain from its low-altitude mapping orbit (LAMO) to its second high-altitude mapping orbit (HAMO2).

Dawn spent nearly five months in LAMO, circling the rocky world at an average altitude of 210 kilometers (130 miles) as it acquired a fabulous bounty of pictures; visible, infrared, neutron, and gamma ray spectra; and measurements of the gravity field. As we saw last month, the probe was far more productive in each investigation than the ambitious team members had expected or had ever dared hope it would be. With that outstanding success behind it, it is looking ahead and up to its work in HAMO2, about 680 kilometers (420 miles) high.

Dawn is the first spacecraft to explore Vesta, the second most massive resident of the main asteroid belt between Mars and Jupiter. Indeed, this is the only craft ever to orbit a body in the asteroid belt. No other missions are currently on the books to visit this remote, exotic world, which is now appreciated to be more closely related to the terrestrial planets (including Earth) than to typical asteroids. And now Dawn is receding from it. On May 1, it began the slow ascent to its next observation orbit. It may well be decades before another robotic ambassador from Earth comes as close to Vesta as this bold traveler has.

Humankind’s first exploration of Vesta has been exceptionally rewarding. A simple measure of that can be seen with just two photographs. More than two centuries after its discovery, this giant asteroid was first glimpsed by the approaching spaceship from Earth on May 3, 2011. From a distance of 1.2 million kilometers (750 thousand miles), or more than three times the separation between Earth and the moon, Dawn’s mapping camera perceived Vesta as only five pixels across. Each pixel spanned more than 110 kilometers (70 miles), revealing nothing new compared to what astronomers’ most powerful telescopes had shown (but the image was of importance for navigation purposes). Nevertheless, at the time, it was tremendously exciting to obtain the first views of a distant, unfamiliar shore after a voyage of more than 2.6 billion kilometers (1.6 billion miles) on the interplanetary ocean. Sighting our first celestial port of call more than three and a half years after this cosmic adventure began was thrilling indeed. But now, with more than 25 thousand spectacular photos in hand from much smaller distances, it is even more gratifying to acknowledge that first picture as one of the worst ever taken of Vesta. The Image of the Day from one year later
was acquired in October 2011 from 1,700 times closer; and most of the images have been obtained from LAMO, about 5,700 times nearer than that first one. Dawn has rapidly transformed Vesta from a mere fleck among the stars into a fascinating, complex and splendidly detailed world.

Keeping the remote vessel on the planned spiraling course from one mapping orbit to another presents the crew with a set of formidable challenges, but this team has accomplished the maneuvers to successively reach survey orbit, the first high-altitude mapping orbit (HAMO1) and LAMO. The current orbital transfer is complex and demanding, but it is proceeding very well. Controllers update the flight profile every few days to ensure the probe stays close to the carefully designed trajectory to HAMO2. To gain a sense of the progress, go here for your correspondent’s atypically succinct weekly summaries of the spiral status.

› Continue reading Marc Rayman’s Dawn Journal


Slice of History: Something is Missing …

Monday, June 4th, 2012

By Julie Cooper

Each month in “Slice of History” we feature a historical photo from the JPL Archives. See more historical photos and explore the JPL Archives at https://beacon.jpl.nasa.gov/.

A large pond and smaller building 264 at JPL
Something is Missing … — Photograph Number JB-16114B

To anyone who came to NASA’s Jet Propulsion Laboratory in Pasadena, Calif., after 1975, this photo may seem odd – building 264 has only two stories, and there is a large pond running down the middle of the mall.

In September 1970, construction began on building 264, the Systems Development Laboratory, a support facility for the Space Flight Operations Facility in building 230. A 7.5 foot tunnel connected the two buildings, lined with racks to support the cables and wiring that joined them. It was constructed as a two story building with a foundation capable of supporting six additional floors, although JPL had to wait several years for additional funding to be approved. The building was finally completed late in 1975, providing mission support for the Viking and Voyager missions, computer space, and three floors of office space.

The pond was nearly 300 feet long, stretching from the mall fountain to a parking area at the east end of building 183. It was built in 1967 and removed by about 1989, but the fountain remains.

This post was written for “Historical Photo of the Month,” a blog by Julie Cooper of JPL’s Library and Archives Group.


Slice of History: Scanning Electron Microscope

Thursday, May 10th, 2012

By Julie Cooper

Each month in “Slice of History” we feature a historical photo from the JPL Archives. See more historical photos and explore the JPL Archives at https://beacon.jpl.nasa.gov/.

Scanning Electron Microscope
Scanning Electron Microscope — Photograph Number 354-1043B

In late 1967, this Stereoscan Mark VI scanning electron microscope (SEM) was delivered to NASA’s Jet Propulsion Laboratory by the Cambridge Instrument Company. They were in high demand at the time, and JPL had to wait nearly a year between placing the order and delivery. It was used by the Electronic Parts Engineering Section Failure Analysis Laboratory to examine microcircuits for defects. Other possible uses were for the study of metals and other materials, and to examine spores for the Capsule Sterilization Program. It used an electron beam to scan the specimen rather than visible light, at a magnification of 20X to 50,000X. The camera on the front right side could be used to record the images.

This post was written for “Historical Photo of the Month,” a blog by Julie Cooper of JPL’s Library and Archives Group.


Dawn Ascends Over Asteroid Vesta

Wednesday, May 2nd, 2012

By Marc Rayman

As NASA’s Dawn spacecraft investigates its first target, the giant asteroid Vesta, Marc Rayman, Dawn’s chief engineer, shares a monthly update on the mission’s progress.

Artist's concept of the Dawn spacecraft at asteroid Vesta
This artist’s concept shows NASA’s Dawn spacecraft orbiting the giant asteroid Vesta. The depiction of Vesta is based on images obtained by Dawn’s framing cameras. Image credit: NASA/JPL-Caltech |
› Full image and caption

Dear Dawnright Spectacular Readers,

Dawn is wrapping up a spectacularly rewarding phase of its mission of exploration. Since descending to its low-altitude mapping orbit (LAMO) in December, the stalwart probe has circled Vesta about 800 times and collected a truly outstanding trove of precious observations of the protoplanet. Having far exceeded the plans, expectations, and even hopes for what it would accomplish when LAMO began, the ambitious explorer is now ready to begin its ascent. On May 1, atop its familiar blue-green pillar of xenon ions, the craft will embark upon the six-week spiral to its second high-altitude mapping orbit.

When the intricate plans for Dawn’s one-year orbital residence at Vesta were developed, LAMO was to be 70 days, longer than any other phase. Because of the many daunting challenges of exploring an uncharted, alien world in the forbidding depths of the asteroid belt so far from home, mission planners could not be confident of staying on a rigid schedule, and yet they wanted to make the most of the precious time at the giant asteroid. They set aside 40 days (with no committed activities) to use as needed in overcoming problems during the unique approach and entry into orbit as well as the intensive observation campaigns in survey orbit and the first high-altitude mapping orbit plus the complex spiral flights from each science orbit to the next. To no one’s surprise, unexpected problems did indeed arise on occasion, and yet in every case, the dedicated professionalism and expertise of the team (occasionally augmented with cortisol, caffeine, and carbohydrates) allowed the expedition to remain on track without needing to draw on that reserve. To everyone’s surprise and great delight, by the beginning of LAMO on December 12, the entirety of the 40 days remained available. Therefore, all of it was used to extend the time the spacecraft would spend at low altitude studying the fascinating world beneath it.

Dawn’s mission at Vesta, exciting and successful though it is, is not the craft’s sole objective. Thanks to the extraordinary capability of its ion propulsion system, this is the first vessel ever planned to orbit two extraterrestrial destinations. After it completes its scrutiny of the behemoth it now orbits, the second most massive resident of the main asteroid belt, Dawn will set sail for dwarf planet Ceres, the largest body between the orbits of Mars and Jupiter.

Since 2009, the interplanetary itinerary has included breaking out of Vesta orbit in July 2012 in order to arrive at Ceres on schedule in February 2015. Taking advantage of additional information they have gained on the spacecraft’s generation and consumption of electrical power, the performance of the ion propulsion system, and other technical issues, engineers have refined their analyses for how long the journey through the asteroid belt to Ceres will take. Their latest assessment is that they can shave 40 days off the previous plan, once again demonstrating the valuable flexibility of ion propulsion, and that translates into being able to stay that much longer at the current celestial residence. (This extension is different from the 40 days described above, because that was designed to ensure Dawn could complete its studies and still leave on schedule in July. For this new extension, the departure date is being changed.) Even though a larger operations team is required at Vesta than during the cruise to Ceres, the Dawn project has the wherewithal to cover the cost. Because operations at Vesta have been so smooth, no new funds from NASA are needed; rather, the project can use the money it had held in reserve in case of problems. In this new schedule, Dawn will gently free itself of Vesta’s gravitational hold on August 26.

Most of the bonus time has been devoted to extending LAMO by a month, allowing the already richly productive investigations there to be even better. (Future logs will describe how the rest of the additional time at Vesta will be spent.) With all sensors fully operational, the robotic explorer has been making the best possible use of its precious time at Vesta, revealing more and more thrilling details of an exotic world deep in the asteroid belt.

› Continue reading Marc Rayman’s Dawn Journal


Alien vs. Editor: A Pigment of Your Imagination?

Friday, March 30th, 2012

By Steve Edberg

Alien vs. Editor is a forum for questions and answers about extrasolar planets and NASA’s search for life beyond our solar system. Leave your questions for author Steve Edberg and read more on the PlanetQuest website.

Fantasy alien landscape
Where would blue-skinned aliens exist?

Joel asked: If you were to find aliens next to the sun, why would they be blue?

The only blue aliens I’m aware of lived on a moon called Pandora in a popular movie released in 2009. The foundation of your question is the more general question of why we observe a wide variety of colors “used” by life on Earth. Those colors are “used” by their organisms in many different ways. And there are a variety of mechanisms that generate the colors.

The colors of plants and animals have a variety of goals. For plants, the green of their leaves comes from the chlorophyll that absorbs violet-blue and yellow-orange-red light for photosynthesis. Some plants (like Japanese plum) have additional pigments for protection from ultraviolet light and appear dark red. Flowers have colors specifically to attract pollinators, but the colors the pollinators see may not be the colors we see.

Animals have colors to camouflage themselves and attract mates. Some plant and animal coloring is designed to warn off predators. The red eye you see in flash pictures of your friends is a reflection of their eyes’ retinas. Photographs of dogs show their retinas reflect greenish light. Is retinal color related to color vision? Most humans have color vision and dogs are color blind.

The colors we see around us are generated by different mechanisms, which can reflect (pun intended) on its use by an organism. The color of a pigment depends on the colors it absorbs and those it reflects. Chlorophyll is a green pigment, and hair and skin colors result from pigments as well.

polar bear
Polar bear fur only looks white.

Polar bears’ black skin pigmentation helps keep them warm. The bears’ white fur only looks white in bulk. Individual hair follicles are actually transparent, so that they carry sunlight down from the “top” of the fur coat to the bear’s skin, where all the colors of sunlight (you’ve seen them in a rainbow made by differential refraction, another mechanism!) are absorbed by the black skin, helping to keep the polar bear warm. The fiber optics we use to transfer data over the internet or between components in your home entertainment system carry light in the same way.

The iridescent color of bird feathers is produced by another mechanism, the same one that makes detergent bubbles and thin slicks of oil on water show colors. The structure of feathers and thickness of detergent and oil layers permits waves of light to “interfere” with each other. You’ve seen wave interference in a quiet pool or pond when you throw two small objects into the water and the circular waves move out from each impact point. When the waves cross over each other, their height is greater where the peaks combine and flat where a peak and a valley combine.

A similar thing happens with light waves in iridescent materials. In the feathers, waves of a particular color are reflected and combined before they are shunted out of the feather, while the other colors are absorbed by a black pigment. The colors come from the spacing of tiny reflectors, called lamellae, in the feathers: change the spacing and the color coming from the feather is different. In detergent bubbles and oil slicks, change the layer’s thickness and you change the color seen.

So where might we expect blue-skinned aliens? My answer is on an exoplanet orbiting a cool, red star. Why? Because the alien probably wants to absorb as much stellar energy as it can from its star, and blue pigments absorb red light. It would be well-camouflaged in the blue vegetation trying to absorb as much energy from the red sun as it could.


All Eyes on Asteroid Vesta

Friday, March 30th, 2012

By Marc Rayman

As NASA’s Dawn spacecraft investigates its first target, the giant asteroid Vesta, Marc Rayman, Dawn’s chief engineer, shares a monthly update on the mission’s progress.

Layered young crater as imaged by NASA's Dawn spacecraft
This image from NASA’s Dawn spacecraft shows a young crater on Vesta that is 9 miles (15 kilometers) in diameter. Layering is visible in the crater walls, as are large boulders that were thrown out in the material ejected from the impact. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA |
› Full image and caption

Dear Dawnscoverers,

On March 29, Vesta spent the 205th anniversary of its discovery by treating Dawn to more spectacular vistas, as it does so often these days. When Heinrich Wilhelm Matthäus Olbers first spotted Vesta, he could hardly have imagined that the power of the noble human spirit for adventure and the insatiable hunger for knowledge would propel a ship from Earth to that mysterious point of light among the stars. And yet today our spacecraft is conducting a detailed and richly rewarding exploration of the world that Olbers found.

Dawn is continuing its intensive low-altitude mapping orbit (LAMO) campaign, scrutinizing the protoplanet 210 kilometers (130 miles) beneath it with all instruments. The primary objectives of the craft’s work here are to measure the atomic composition and the interior distribution of mass in this geologically complex world. In addition, this low orbit provides the best vantage point for high resolution pictures and visible and infrared spectra to reveal the nature of the minerals on the surface.

Ever since it left its home planet behind in September 2007, the robotic adventurer has pursued its own independent course through the solar system. As Earth and its orbiting retinue (including the moon and many artificial satellites) followed their repetitive annual loop around the sun, Dawn used its ion propulsion system to spiral outward to rendezvous with Vesta in July 2011. When the gigantic asteroid’s gravity gently took hold of the visiting craft, the two began traveling together around the sun, taking the same route Vesta has since long before humans gazed in wonder at the nighttime sky.

As we have discussed before, the speed of an object in orbit, whether around Earth, the sun, the Milky Way (either my cat or the galaxy of the same name) or anything else, decreases as its orbital altitude increases. Farther from the sun than Earth is, and hence bound to it by a weaker gravitational grip, Vesta moves at a more leisurely pace, taking more than 3.6 years per revolution. When Dawn travels to the more remote Ceres, it will orbit the sun even more slowly, eventually matching Ceres’ rate of 4.6 years for each loop.

Just as the hour hand and minute hand of a clock occasionally are near each other and at other times are on opposite sides of the clock face, Earth and Dawn sometimes are relatively close and other times are much farther apart. Now their orbits are taking them to opposite sides of the sun, and the distance is staggering. They have been on opposite sides of the sun twice before (albeit not as far apart as this time), in November 2008 and November 2010. We used both occasions to explain more about the nature of the alignment as well as to contemplate the profundity of such grand adventures.

On April 18, Dawn will attain its greatest separation yet from Earth, nearly 520 million kilometers (323 million miles) or more than 3.47 astronomical units (AU). Well beyond Mars, fewer than a dozen spacecraft have ever operated so far from Earth. Those interested in the history of space exploration (such as your correspondent) will enumerate them, but what should be more rewarding is marveling at the extent of humanity’s reach. At this extraordinary range, Dawn will be nearly 1,400 times farther than the average distance to the moon (and 1,300 times farther than the greatest distance attained by Apollo astronauts 42 years ago). The deep-space ship will be well over one million times farther from Earth than the International Space Station and Tiangong-1.

Vesta does not orbit the sun in the same plane that Earth does. Indeed, a significant part of the challenge in matching Dawn’s orbit to Vesta’s was tipping the plane of its orbit from Earth’s, where it began its journey, to Vesta’s, where it is now. As a result, when they are on opposite sides of the sun this time, Dawn will not appear to go directly behind the sun but rather will pass a little south of it. In addition, because the orbits are not perfectly circular, the greatest separation does not quite coincide with the time that Dawn and the sun appear to be most closely aligned. The angular separation will be at its minimum of less than five degrees (about 10 times the angular size of the sun itself) on April 9, but the sun and Dawn appear to be within ten degrees of each other from March 23 until April 27. For our human readers, that small angle is comparable to the width of your palm at arm’s length, providing a handy way to find the approximate position of the spacecraft in the sky. Earth’s robotic ambassador to the cosmos began east of the salient celestial signpost and progresses slowly to the west over the course of those five weeks. Readers are encouraged to step outside and join your correspondent in raising a saluting hand to the sun, Dawn, and what we jointly accomplish in our efforts to gain a perspective on our place in the universe.

For those awestruck observers who lack the requisite superhuman visual acuity to discern the faraway spacecraft amidst the dazzling light of the sun, this alignment provides a convenient occasion to reflect once again upon missions deep into space. Formed at the dawn of the solar system, Vesta, arguably the smallest of the terrestrial planets, has waited mostly in patient inconspicuousness for a visit from the largest terrestrial planet. For the entire history of life on Earth, the inhabitants remained confined to the world on which they have lived. Yet finally, one of the millions upon millions of species, inspired by the splendor of the universe, applied its extraordinary talents and collective knowledge to overcome the limitations of planetary life and strove to venture outward. Dawn is the product of creatures fortunate enough to be able to combine their powerful curiosity about the workings of the cosmos with their impressive abilities to explore, investigate and ultimately understand. While its builders remain in the vicinity of the planet upon which they evolved, their emissary now is passing on the far side of the sun! This is the same sun that is more than 100 times the diameter of Earth and a third of a million times its mass. This is the same sun that has been the unchallenged master of our solar system for more than 4.5 billion years. This is the same sun that has shone down on Earth throughout that time and has been the ultimate source of so much of the heat, light and other energy upon which the planet’s residents have been so dependent. This is the same sun that has so influenced human expression in art, literature, mythology and religion for uncounted millennia. This is the same sun that has motivated scientific studies for centuries. This is the same sun that is our signpost in the Milky Way galaxy. And humans have a spacecraft on the far side of it. We may be humbled by our own insignificance in the universe, yet we still undertake the most valiant adventures in our attempts to comprehend its majesty.

Dawn is 210 kilometers (130 miles) from Vesta. It is also 3.45 AU (516 million kilometers or 321 million miles) from Earth, or 1,290 times as far as the moon and 3.45 times as far as the sun today. Radio signals, traveling at the universal limit of the speed of light, take 57 minutes to make the round trip.


Highs and Lows of Exploring the Giant Asteroid

Friday, March 2nd, 2012

By Marc Rayman

As NASA’s Dawn spacecraft investigates its first target, the giant asteroid Vesta, Marc Rayman, Dawn’s chief engineer, shares a monthly update on the mission’s progress.

Artist's concept of the Dawn spacecraft soaring over the giant asteroid Vesta.
This artist’s concept shows NASA’s Dawn spacecraft orbiting the giant asteroid Vesta. The depiction of Vesta is based on images obtained by Dawn’s framing cameras. Image credit: NASA/JPL-Caltech |
› Full image and caption

Dear Ups and Dawns,

Dawn is continuing its exploits at Vesta, performing detailed studies of the colossal asteroid from its low altitude mapping orbit (LAMO). The robotic ambassador is operating extremely well on behalf of the creatures it represents on a distant planet. On this second intercalary day of its ambitious adventure, the spacecraft is doing exactly what it was designed to do: exploring a previously uncharted alien world.

Although we usually describe LAMO as being at an average altitude of 210 kilometers (130 miles), that does not mean it is at a constant altitude. As we saw on the fourth anniversary of Dawn’s departure from Earth, there are two reasons the spacecraft’s height changes. One is that the elevation of the surface itself changes, so if the probe flew in a perfect circle around Vesta, its altitude would vary according to the topography. Like the planet from which Dawn embarked upon its deep space journey in 2007 (and even some of the residents there), Vesta is broadest near its equator, and that is where the ground generally reaches its greatest distance from the center. In addition, the ancient surface, battered over billions of years in the rough and tumble of the asteroid belt, displays remarkable variations in shape. The giant Rheasilvia basin is a scar from an extraordinary impact that excavated a region encompassing the south pole more than 500 kilometers (over 300 miles) in diameter. This immense gouge has left that part of Vesta at a much lower elevation than elsewhere. In the center of the enormous depression is the second tallest mountain known in the solar system, soaring to well over twice the height of Mt. Everest. The vertical range from the highest locations near the equator to the bottoms of the deepest craters within Rheasilvia is more than 60 kilometers (37 miles). So as Dawn loops around in just over four hours, the surface underneath it rises and falls dramatically.

The second reason is that the orbit itself is not exactly a circle. Let’s ignore for a moment the effect of the topography and focus solely on the shape of the craft’s path around Vesta. As Vesta rotates and Dawn revolves, the gravitational forces acting on the orbiter are always changing because of the irregular distribution of material inside the geologically complex protoplanet. This effect occurred at the higher altitudes as well, but it was much less pronounced there. Now that the adventurer is deep in the gravity field, the peaks and valleys of its own motion are magnified.

Navigators were very careful in choosing the parameters for LAMO, recognizing that the orbital waters were turbulent. Nevertheless, their mapping of the gravitational currents proved quite accurate, and the spacecraft has followed the planned course quite well. The lengthy and relatively technical discussions in the two previous logs described why the ship drifts off a little, but operators occasionally nudge it back with the ion propulsion system.

Orbits usually are best described by ellipses, like flattened circles. Now Vesta’s bumpy gravity field does not allow perfectly smooth, regular orbits at low altitude. Moreover, the variations in the strength of the gravitational attraction transform the orbits. Sometimes, the difference between the high point of a loop and the low point is less than 16 kilometers (10 miles). As the changing forces reshape the orbit, the ellipse gets more exaggerated, with the low points going lower and the high points going higher. The differences within one revolution grow to be more than 75 kilometers (47 miles). Thanks to the ingenious design of the orbital trajectory however, those same forces then will gradually attenuate the profile, causing it to become more round again. This pattern repeats every 11.5 days in LAMO. It is almost as if the orbit breathes slowly, its envelope expanding and contracting.

› Continue reading Marc Rayman’s Dawn Journal


Slice of History: Vice President Lyndon Johnson Visits JPL

Monday, February 27th, 2012

By Julie Cooper

Each month in “Slice of History” we feature a historical photo from the JPL Archives. See more historical photos and explore the JPL Archives at https://beacon.jpl.nasa.gov/.

Vice President Lyndon Johnson Visits JPL
Vice President Lyndon Johnson Visits JPL — Photograph Number P-1723A

On October 4, 1961, Vice President Lyndon B. Johnson visited NASA’s Jet Propulsion Laboratory in Pasadena, Calif. In his role as chairman of the National Aeronautics and Space Council, he toured the Lab and heard presentations about JPL’s lunar programs (Ranger and Surveyor), planetary program, the Deep Space Network and future plans. President John F. Kennedy had made his presentation to Congress several months earlier about putting a man on the moon before the decade ended. During the 1960s, JPL’s role shifted somewhat from lunar and planetary exploration to support of and preparation for manned missions to the moon and planets.

This photo shows Johnson walking out of the cafeteria (then located in Building 114) with JPL Director William Pickering while employees gathered around.

This post was written for “Historical Photo of the Month,” a blog by Julie Cooper of JPL’s Library and Archives Group.


A Look Inside Dawn’s Grand Asteroid Adventure

Wednesday, February 1st, 2012

By Marc Rayman

As NASA’s Dawn spacecraft investigates its first target, the giant asteroid Vesta, Marc Rayman, Dawn’s chief engineer, shares a monthly update on the mission’s progress.

Image of asteroid Vesta taken by NASA's Dawn spacecraft from low altitude mapping orbit, or LAMO
The south pole of the giant asteroid Vesta, as imaged by the framing camera on NASA’s Dawn spacecraft in September 2011. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA |
› Full image and caption

Dear Asdawnished Readers,

Dawn is scrutinizing Vesta from its low-altitude mapping orbit (LAMO), circling the rocky world five and a half times a day. The spacecraft is healthy and continuing its intensive campaign to reveal the astonishing nature of this body in the mysterious depths of the main asteroid belt.

Since the last log, the robotic explorer has devoted most of its time to its two primary scientific objectives in this phase of the mission. With its gamma ray and neutron detector (GRaND), it has been patiently measuring Vesta’s very faint nuclear emanations. These signals reveal the atomic constituents of the material near the surface. Dawn also broadcasts a radio beacon with which navigators on distant Earth can track its orbital motion with exquisite accuracy. That allows them to measure Vesta’s gravity field and thereby infer the interior structure of this complex world. In addition to these top priorities, the spacecraft is using its camera and its visible and infrared mapping spectrometer (VIR) to obtain more detailed views than they could in the higher orbits.

As we have delved into these activities in detail in past logs, let’s consider here some more aspects of controlling this extremely remote probe as it peers down at the exotic colossus 210 kilometers (130 miles) beneath it.

Well, the first aspect that is worth noting is that it is incredibly cool! Continuing to bring this fascinating extraterrestrial orb into sharper focus is thrilling, and everyone who is moved by humankind’s bold efforts to reach into the cosmos shares in the experience. As a reminder, you can see the extraordinary sights Dawn has by going here for a new image every weekday, each revealing another intriguing aspect of the diverse landscape.

The data sent back are providing exciting and important new insights into Vesta, and those findings will continue to be announced in press releases. Therefore, we will turn our attention to a second aspect of operating in LAMO. Last month, we saw that various forces contribute to Dawn moving slightly off its planned orbital path. (That material may be worth reviewing, either to enhance appreciation of what follows or as an efficacious soporific, should the need for one ever arise.) Now let’s investigate some of the consequences. This will involve a few more technical points than most logs, but each will be explained, and together they will help illustrate one of the multitudinous complexities that must be overcome to make such a grand adventure successful.

› Continue reading Marc Rayman’s Dawn Journal


Slice of History: Surveyor 3 Camera Returned from the Moon

Tuesday, January 24th, 2012

By Julie Cooper

Each month in “Slice of History” we feature a historical photo from the JPL Archives. See more historical photos and explore the JPL Archives at https://beacon.jpl.nasa.gov/.

ASurveyor 3 Camera Returned from the Moon
Surveyor 3 Camera Returned from the Moon — Photograph Number P-10709B

In November 1969 Apollo 12 astronauts Alan Bean and Pete Conrad landed on the moon less than 600 feet from NASA’s Surveyor 3 spacecraft, which had been there since April 1967. They removed the camera, some cable and tubing, and the trenching scoop from the lander and brought them back to Earth so that the effects of prolonged lunar exposure could be studied by Hughes Aircraft Company (the spacecraft prime contractor) and NASA’s Jet Propulsion Laboratory. The Surveyor 3 camera was kept under quarantine and studied for several weeks at the Lunar Receiving Laboratory in Houston. Then it was shipped to the Hughes facility in Culver City, Calif. This photo was taken in January 1970, probably at the Hughes facility, where Hughes and JPL employees photographed, disassembled and studied the camera in detail.

This post was written for “Historical Photo of the Month,” a blog by Julie Cooper of JPL’s Library and Archives Group.


Viewing Times and Tips for Saturday Morning’s Lunar Eclipse

Friday, December 9th, 2011

By Steve Edberg

The last lunar eclipse until 2014 will grace the sky on Saturday, Dec. 10. Steve Edberg, an astronomer at NASA’s Jet Propulsion Laboratory, shares the best viewing times and tips. For more lunar eclipse resources and to join NASA/JPL’s “I’m There: Lunar Eclipse” event, visit http://1.usa.gov/uBfAI8.

Lunar eclipse 2010 photo by Keith Burns
Keith Burns submitted this winning photo of the December 2010 lunar eclipse as part of NASA/JPL’s “I’m There: Lunar Eclipse” Wallpaper contest. Planning to “be there” for the Dec. 10, 2011 eclipse? Post your images on the Total Lunar Eclipse Facebook event page for a chance to have your photo become an official NASA/JPL wallpaper. Copyright: Keith Burns

In the hours before dawn on Saturday morning, December 10, early risers in about half of the continental U.S. will have a chance to see at least some of a total lunar eclipse – the last one until 2014. The moon will be low in the western sky, and a clear, flat horizon without obscuring trees, buildings or mountains will make viewing easier. The setting of the moon and brightening of the sky as the sun rises will make observing the eclipse more challenging than usual, but more interesting too.

The moon’s passage has stages as it goes through the layers of Earth’s shadow. The outer ring of the shadow is called the penumbra. An observer on the moon would see a partial solar eclipse while the moon is in the penumbra. The core of Earth’s shadow is called the umbra. Observers on the moon would see a total eclipse of the sun when the moon is in the umbra. The time of moonset and the moon’s position in the earth’s shadow affects the view of the various stages of the event for observers across the US.

Washington, D.C. and the Eastern Time zone: The moon is setting just when it first enters the outer ring of Earth’s shadow. (This is called first penumbral contact, 06:33 EST, 05:33 CST, 04:33 MST, 03:33 PST, 01:33 AHST.) Effectively, no eclipse is visible. Sorry.

Chicago and the Central Time zone: Moonset is just before the moon enters the dark core of Earth’s shadow (called first umbral contact, 06:45 CST, 05:45 MST, 04:45 PST, 02:45 AHST). Observers in this region might see some darkening of a small section of the moon, just before the moon dips below the horizon.

Albuquerque and the Mountain Time zone: The moon sets (06:52 MST) with about 65 percent of its surface in the core of Earth’s shadow. Observers in this region will be able to see the moon’s entry and motion through Earth’s shadow until the moon disappears.

Los Angeles and the Pacific Time zone: With some variation from San Diego to Seattle, observers with an ocean horizon will be able to see the moon completely covered by the core of Earth’s shadow. (This is called totality, beginning at 06:06 PST, 04:06 AHST.) Southern observers will see a race between the end of totality and moonset. Observers in the Pacific Northwest will see the moon begin to emerge from the shadow core, ending totality (at 06:57 PST, 04:57 AHST). For them, the moon goes down (07:46 PST) in partial eclipse.

Honolulu and the Hawaiian Islands: Observers will see all phases involving the shadow core. Moonset occurs (07:05 AHST) after the last umbral contact, during the ending phase as the moon is exiting the outer ring of Earth’s shadow.

Anchorage, Alaska and northwestern Canada: The complete eclipse — from shadow outer ring entry, the moon’s passage through the shadow core, and its exit from the outer ring — will be visible before sunrise. The long nights at these latitudes make this possible.

The last total lunar eclipse visible in the US was about a year ago. Some of us will see a partial lunar eclipse next June, but after that we all wait until April 14-15, 2014 to see the whole spectacle of the moon passing through Earth’s shadow.


Getting the Lowdown on Asteroid Vesta

Monday, December 5th, 2011

By Marc Rayman

As NASA’s Dawn spacecraft investigates its first target, the giant asteroid Vesta, Marc Rayman, Dawn’s chief engineer, shares a monthly update on the mission’s progress.

Still from a 3-D video incorporating images from NASA's Dawn spacecraft
This 3-D video incorporates images from the framing camera instrument aboard NASA’s Dawn spacecraft from July to August 2011. The images were obtained as Dawn approached Vesta and circled the giant asteroid during the mission’s survey orbit phase. Survey orbit took place at an altitude of about 1,700 miles (2,700 kilometers). To view this video in 3-D use red-green, or red-blue, glasses (left eye: red; right eye: green/blue). Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
› See video

Dear Dawnward Spirals,

Continuing its ambitious campaign of exploration deep in the asteroid belt, Dawn has spent most of the past month spiraling ever closer to Vesta. Fresh from the phenomenal success of mapping the alien world in detail in October, the spacecraft and its human team members are engaged in one of the most complicated parts of the mission. The reward will be the capability to scrutinize this fascinating protoplanet further.

Thanks to the extraordinary performance of its ion propulsion system, Dawn can maneuver to different orbits that are best suited for conducting each of its scientific observations. The probe is now headed for its low altitude mapping orbit (LAMO), where the focus of its investigations will be on making a census of the atomic constituents with its gamma ray and neutron sensors and on mapping the gravity field in order to determine the interior structure of this protoplanet.

As secondary objectives, Dawn will acquire more images with its camera and more spectra with its visible and infrared mapping spectrometer. As we will see in a future log, these measurements will receive a smaller share of the resources than the high priority studies. The spectacular pictures obtained already will keep scientists happy for years, and you can continue to share in the experience of marveling at the astonishing discoveries by seeing some of the best views here, including scenes captured during the spiral to LAMO.

Planning the low altitude mapping orbit around massive Vesta, with its complicated gravity field, required a great deal of sophisticated analysis. Before Dawn arrived, mission designers studied a range of possible gravitational characteristics and honed the methods they would use for plotting the actual orbit once the details of the protoplanet’s properties were ascertained. In the meantime, the team used a tentative orbit at an altitude over the equator of 180 kilometers (110 miles). As explained in a previous log, the altitude varies both because the orbit is not perfectly circular and because Vesta displays such exceptional topography. The highest elevations turn out to be at the equator, and the average altitude of that orbit would be 200 kilometers (125 miles).

Now that navigators have measured Vesta’s gravity, they have the knowledge to refine the design for LAMO, and they decided to raise it by 10 kilometers (6 miles). The target then is an average altitude of 210 kilometers (130 miles). But there is more to the specification of the orbit than simply its height. To meet all of the scientific objectives, the orientation of this orbit needs to be different from the orientation of the previous orbits, the high altitude mapping orbit (HAMO) and survey orbit.

› Continue reading Marc Rayman’s Dawn Journal


Mission Control to Mars: Launching the Next Mars Rover

Monday, November 28th, 2011

By Rob Manning

In the wee morning hours of Nov. 26, 2011, scientists and engineers gathered in the mission control room at NASA’s Jet Propulsion Laboratory to help launch the next Mars rover, Curiosity. The mission’s chief engineer, Rob Manning, shares the developing story from the control room as tensions and excitement for a mission eight years in the making reached all new heights.

NASA's Mars Science Laboratory spacecraft, sealed inside its payload fairing atop the United Launch Alliance Atlas V rocket
NASA’s Mars Science Laboratory spacecraft, sealed inside its payload fairing atop the United Launch Alliance Atlas V rocket, launched on Nov. 26 from Kennedy Space Center in Florida.

5:45 a.m. PST (L-01:17:00)
I drove in this morning at 4:30 a.m. As usual, I was greeted by the cheery guards at the gate along with a small family of local deer, who keep sentry over a small patch of greenery at NASA’s Jet Propulsion Laboratory.

I quickly march into JPL’s mission control area to find the first shift quietly following the prelaunch procedure in sync with the Assembly, Test and Launch Operations (ATLO) procedure. They had been on station since 1:30 a.m. I tried that procedure at last week’s launch rehearsal and found the hour a bit unpleasant. Today, I am working on the Anomaly Response Team (ART) for post-launch anomalies. This means that if all goes well, I will have little to do but cheer when NASA’s Mars Science Laboratory rover launches. I have my own console where I can monitor both the spacecraft and listen to the voice nets (there are 10 of them!).

There are about 30 people here. Usually there are not as many, but today we have two people for every subsystem: power, thermal, propulsion, systems, fault protection, attitude control and management. I can hear the JPL ATLO test conductor, Art Thompson, at NASA’s Kennedy Space Center in Florida double check that the right sequence files have been sent. One in particular has commands that tell the rover when to automatically transition into “eclipse” mode. This software mode puts the entire vehicle into the configuration needed for the period prior to separation from the Centaur. In particular this mode turns on the descent stage and cruise stage tank heaters. This timer should be set about 15 minutes after launch, which is planned for 7:02 am PST today. It is an absolute time so they have to send a new time every time we have a new launch attempt. The voice net that is the most interesting is the launch vehicle’s fueling operations. I have not heard that one before. They are more than 50 percent of the way through fueling!

It is fun to see the crowd here. No dress code, but some have come in ties, others with pink mohawks. Nice combo. Professionals all. The peanuts have already made the rounds.

6:15 a.m. (L-00:47:00)
Brian Portock, today’s flight director at JPL, just finished the launch poll of the room to see if everyone is go for transition to launch mode. This is a command to the rover that will put everything on the rover into a mode that is used for the first 15 minutes of flight. In particular, the heaters are all put into a launch and cruise configuration. We expect that the cruise stage heaters will be on more than off due to the air conditioning needed to keep the spacecraft cool (hot generators, you know).

6:29 a.m. (L-00:33:00)
Arm pyros! Once these relays are closed, they will be that way for the next 8.5 months.

6:32 a.m. (L-00:30:00)
The data rate is lowered to launch nominal to 200 bits per second. This will allow the rover’s data to flow to both the ground (via wires to the power van at the foot of the launch pad that provides power to the rover before launch) and to the launch vehicle where it will be available throughout launch (very cool). The JPL management showed up. Charles Elachi is behind me. My old friend and JPL Chief Engineer Brian Muirhead is here with his family.

6:40 a.m. (L-00:22:00)
The flight director is doing the launch poll for the team here at JPL: “All stations at JPL report go.” ATLO is going through its poll at lightening speed. All stations go. This is going fast! The weather guys report of scattered skies at 5,000 feet looks good. I am getting excited.

6:47 a.m. (L-00:15:00)
We lost the flow of data from MSL via the Atlas Space Flight Operations Center (ASOC) land lines, but they switch it to the radio path from the launch vehicle, and it starts flowing again.

7:00 a.m. (L-00:02:00)
All Quiet. Peanuts going around the room again … everyone is excited!

7:01 a.m. (L-00:01:20)
Everything is armed …

7:01 a.m. (L-00:00:30)
GO ATLAS! GO CENTAUR!

7:03 a.m. (L+00:01:00)
GO, GO, GO!

7:06 a.m. (L+00:04:00)
Fairing falls off! Wind on MSL ;)

7:07 a.m. (L+00:05:00)
Rob Zimmerman, our power systems engineer, reports power on solar arrays! 3.3 x 2 = 6. 7 amps! The spacecraft is still power-negative for a while which means that the battery is still discharging. We need more sunlight - very soon.

7:11 a.m. (L+00:09:00)
Getting intermittent data from the rover via the Centaur. So far, no computer reboots!

7:12 a.m. (L+00:10:00)
The ATLO test conductor reports that they are done building and launching MSL (hey, it took ‘em long enough! ;) ). We all cheer and smile. They are supporting the cruise team now.

7:14 a.m. (L+00:12:00)
We’ve reached the end of the first burn (MECO1). All is well. Eighteen minutes to second burn. Battery is charging at 4.3 amps for each battery — very good.

7:17 a.m. (L+00:15:00)
The eclipse-mode transition should be done; don’t know yet. Got it. The tank heaters should be on now; They are. Batteries are still charging at 95 percent state of charge (SOC).

7:35 a.m. (L+00:33:00)
Waiting for telemetry from over Africa …

7:36 a.m. (L+00:34:00)
It’s five minutes to MECO2, pushing out of Earth orbit. Heavy rover! KEEP PUSHING! Mars awaits.

7:39 a.m. (L+00:37:00)
The spacecraft is nearly out of Earth orbit, six minutes until separation from Centaur upper stage. Everyone is relaxed, but there’s not a lot of data from the rover. It still says it is in launch mode — missed the data that said eclipse.

7:42 a.m. (L+00:40:00)
MECO2. next is turn to separation attitude and spin up. Separation! We get a beautiful view of MSL spinning away from us — in the right attitude and the right direction! (› See Video)

The
Video: The Mars Science Laboratory spacecraft separates from the upper stage of its Atlas V launch vehicle and heads on its way to Mars.
› See video

7:53 a.m. (L+00:51:00)
We have lock from NASA’s Deed Space Network in Canberra, Australia!

8:07 a.m. (L+01:05:00)
Data-slowing coming … All looks good, batteries at 98 percent. The rover is now in cruise mode. The heaters are on and cycling as designed. The spacecraft is spinning at 2.5 rotations per minute with only 1 degree of nutation (or swaying) — that is not a lot. The Atlas and Centaur did a fantastic job! The generator is working.

8:26 a.m. (L+01:24:00)
Now let’s try the uplink (sweep). Sweep is working! We have strong signals both ways. We are getting two-way Doppler - navigation says that the frequency is just a few hertz off so we had a very nominal injection to solar orbit. We can command!

Everyone is relaxed and trying to see if there is anything that looks wrong, but so far, nothing. Everything is fine. This is weird. Our bird is on its way - it’s where it belongs. We are happy to be in a completely new mode. No more last-minute fixes (to anything but the software). We have a lot to do, but at least our bird is on its way.


Slice of History: Advanced Ocean Technology Development Platform

Wednesday, November 9th, 2011

By Julie Cooper

Each month in “Slice of History” we feature a historical photo from the JPL Archives. See more historical photos and explore the JPL Archives at https://beacon.jpl.nasa.gov/.

Advanced Ocean Technology Development Platform
Advanced Ocean Technology Development Platform — Photograph Number P-23298B

The Advanced Ocean Technology Development Platform (AOTDP) was developed at NASA’s Jet Propulsion Laboratory in the late 1970s by the Undersea Technology Program Office. The project applied space program instruments and systems to ocean exploration, mapping and resource assessment. This photo was taken in December 1980, after more than two months of engineering tests around Long Beach and Los Angeles harbors. The AOTDP shallow water test team included, from left to right, Sherry Wheelock, Don Hoff, Gary Bruner, Larry Broms, Curtis Tucker, Hal Holway, Garry Paine, Martin Orton and task manager Bill Gulizia.

The submersible vehicle test platform carried digital side-looking sonar for underwater imaging and a tow cable connecting the submersible to its companion surface ship, providing command, telemetry and power links. There was a shipboard control and data acquisition center to process and display the information gathered by the submersible, at rates of up to 250,000 bits per second. It was designed to descend as deep as 20,000 feet, but test tows were conducted at depths of about 600 feet. The project was funded by NASA and tests designed to improve the side-looking sonar instrument were sponsored by the National Oceanic and Atmospheric Administration (NOAA).

This post was written for “Historical Photo of the Month,” a blog by Julie Cooper of JPL’s Library and Archives Group.