NASA Stardust Spacecraft Officially Ends Operations

NASA's Stardust spacecraft sent its last transmission to Earth at 4:33 p.m. PDT (7:33 p.m. EDT) Thursday, March 24, shortly after depleting fuel and ceasing operations. During a 12-year period, the venerable spacecraft collected and returned comet material to Earth and was reused after the end of its prime mission in 2006 to observe and study another comet during February 2011.

The Stardust team performed the burn to depletion because the comet hunter was literally running on fumes. The depletion maneuver command was sent from the Stardust-NExT mission control area at Lockheed Martin Space Systems in Denver. The operation was designed to fire Stardust's rockets until no fuel remained in the tank or fuel lines. The spacecraft sent acknowledgment of its last command from approximately 312 million kilometers (194 million miles) away in space.



"This is the end of the spacecraft's operations, but really just the beginnings of what this spacecraft's accomplishments will give to planetary science," said Lindley Johnson, Stardust-NExT and Discovery program executive at NASA Headquarters in Washington. "The treasure-trove of science data and engineering information collected and returned by Stardust is invaluable for planning future deep space planetary missions."

After completion of the burn, mission personnel began comparing the computed amount of fuel consumed during the engine firing with the anticipated amount based on consumption models. The models are required to track fuel levels, because there are no fully reliable fuel gauges for spacecraft in the weightless environment of space. Mission planners use approximate fuel usage by reviewing the history of the vehicle's flight, how many times and how long its rocket motors fired.

"Stardust's motors burned for 146 seconds," said Allan Cheuvront, Lockheed Martin Space Systems Company program manager for Stardust-NExT in Denver. "We'll crunch the numbers and see how close the reality matches up with our projections. That will be a great data set to have in our back pocket when we plan for future missions."

Cassini Finds Saturn Sends Mixed Signals

Recent data from NASA's Cassini spacecraft show that the variation in radio waves controlled by the planet's rotation is different in the northern and southern hemispheres. Moreover, the northern and southern rotational variations also appear to change with the Saturnian seasons, and the hemispheres have actually swapped rates. These two radio waves, converted to the human audio range, can be heard in a new video available online at: http://www.nasa.gov/multimedia/videogallery/index.html?media_id=74390781

"These data just go to show how weird Saturn is," said Don Gurnett, Cassini's radio and plasma wave science instrument team lead and professor of physics at the University of Iowa, Iowa City. "We thought we understood these radio wave patterns at gas giants, since Jupiter was so straightforward. Without Cassini's long stay, scientists wouldn't have understood that the radio emissions from Saturn are so different."

Saturn emits radio waves known as Saturn Kilometric Radiation, or SKR for short. To Cassini, they sound a bit like bursts of a spinning air raid siren, since the radio waves vary with each rotation of the planet. This kind of radio wave pattern had been previously used at Jupiter to measure the planet's rotation rate, but at Saturn, as is the case with teenagers, the situation turned out to be much more complicated.

When NASA's Voyager spacecraft visited Saturn in the early 1980s, the radiation emissions indicated the length of Saturn's day was about 10.66 hours. But as its clocking continued by a flyby of the joint ESA-NASA Ulysses spacecraft and Cassini, the radio burst varied by seconds to minutes. A paper in Geophysical Research Letters in 2009 analyzing Cassini data showed that the Saturn Kilometric Radiation was not even a solo, but a duet, with two singers out of sync. Radio waves emanating from near the north pole had a period of around 10.6 hours; radio waves near the south pole had a period of around 10.8 hours.

NASA's Aqua Satellite Spies a "3-leaf Clover" View of Ireland for St. Patrick's Day

Typical clovers have three leaves, unless you happen to be lucky, and NASA's Aqua satellite has provided three different views of Ireland to mark Saint Patrick's Day on March 17, 2011. With the luck o’ the Irish, NASA's Aqua satellite was fortunate to capturemostly clear views of the Emerald Isle in these near-infrared/visible, infrared and microwave light views acquired by Aqua’s Atmospheric Infrared Sounder (AIRS) instrument on March 3, 2011, at 13:11 UTC.

Ireland, located in the Atlantic Ocean, is the third-largest island in Europe, and originated the St. Patrick's Day holiday. Located west of Great Britain and separated from it by the Irish Sea, it is surrounded by hundreds of islands and islets. In March, Ireland's average daytime high temperature is near 9.4 degrees Celsius (49 degrees Fahrenheit) and its average nighttime low temperature is near 3.3 degrees Celsius (38 degrees Fahrenheit).

The AIRS instrument measures temperatures of land, sea and air to provide a better understanding of what is happening in those environments. The March 3 images reveal temperatures near the surface that were near normal for this time of year.

NASA's Aqua satellite circles Earth pole-to-pole 15 times a day in a sun-synchronous orbit to provide data and images to researchers in Earth, ocean and atmospheric sciences. When Aqua passed over Ireland on March 3, it captured visible, infrared and microwave images: a clover of images from one instrument.

Japan Quake May Have Shortened Earth Days, Moved Axis

The March 11, magnitude 9.0 earthquake in Japan may have shortened the length of each Earth day and shifted its axis. But don't worry—you won't notice the difference.

Using a United States Geological Survey estimate for how the fault responsible for the earthquake slipped, research scientist Richard Gross of NASA's Jet Propulsion Laboratory, Pasadena, Calif., applied a complex model to perform a preliminary theoretical calculation of how the Japan earthquake—the fifth largest since 1900—affected Earth's rotation. His calculations indicate that by changing the distribution of Earth's mass, the Japanese earthquake should have caused Earth to rotate a bit faster, shortening the length of the day by about 1.8 microseconds (a microsecond is one millionth of a second).

The calculations also show the Japan quake should have shifted the position of Earth's figure axis (the axis about which Earth's mass is balanced) by about 17 centimeters (6.5 inches), towards 133 degrees east longitude. Earth's figure axis should not be confused with its north-south axis; they are offset by about 10 meters (about 33 feet). This shift in Earth's figure axis will cause Earth to wobble a bit differently as it rotates, but it will not cause a shift of Earth's axis in space—only external forces such as the gravitational attraction of the sun, moon and planets can do that.

Both calculations will likely change as data on the quake are further refined.

In comparison, following last year's magnitude 8.8 earthquake in Chile, Gross estimated the Chile quake should have shortened the length of day by about 1.26 microseconds and shifted Earth's figure axis by about 8 centimeters (3 inches). A similar calculation performed after the 2004 magnitude 9.1 Sumatran earthquake revealed it should have shortened the length of day by 6.8 microseconds and shifted Earth's figure axis by about 7 centimeters, or 2.76 inches. How an individual earthquake affects Earth's rotation depends on its size (magnitude), location and the details of how the fault slipped.

Gross said that, in theory, anything that redistributes Earth's mass will change Earth's rotation.

NASA Light Technology Successfully Reduces Cancer Patients Painful Side Effects from Radiation

A NASA technology originally developed for plant growth experiments on space shuttle missions has successfully reduced the painful side effects resulting from chemotherapy and radiation treatment in bone marrow and stem cell transplant patients.


In a two-year clinical trial, cancer patients undergoing bone marrow or stem cell transplants were given a far red/near infrared Light Emitting Diode treatment called High Emissivity Aluminiferous Luminescent Substrate, or HEALS, to treat oral mucositis -- a common and extremely painful side effect of chemotherapy and radiation treatment. The trial concluded that there is a 96 percent chance that the improvement in pain of those in the high-risk patient group was the result of the HEALS treatment.

"Using this technology as a healing agent was phenomenal," said Dr. Donna Salzman, clinical trial principal investigator and director of clinical services and education at the Bone Marrow Transplant and Cellular Therapy Unit at the University of Alabama at Birmingham Hospital. "The HEALS device was well tolerated with no adverse affects to our bone marrow and stem cell transplant patients."

The HEALS device, known as the WARP 75 light delivery system, can provide a cost-effective therapy since the device itself is less expensive than a day at the hospital and a proactive therapy for symptoms of mucositis that are currently difficult to treat without additional, negative side effects.