Stories tagged stardust

Mar
25
2011

Stardust's burn to depletion: On March 24 four rocket motors on NASA's Stardust spacecraft, illustrated in this artist's concept, fired until the spacecraft's fuel was depleted.
Stardust's burn to depletion: On March 24 four rocket motors on NASA's Stardust spacecraft, illustrated in this artist's concept, fired until the spacecraft's fuel was depleted.Courtesy NASA/JPL-Caltech
Yesterday NASA's Stardust spacecraft performed a final burn with its main engines which effectively ended the life of NASA's most traveled comet hunter. Called a "burn to depletion", the procedure will help to answer the question of how much fuel Stardust had left in its tank. While it sounds like running your snow blower until it runs out of gas to store it for the summer, this was an important test as no one has invented an entirely reliable fuel gauge for spacecraft. Part of the process of approximating fuel use is looking at the history of the vehicle's flight and how many times and for how long its rocket motors have fired.

Stardust's burn to depletion is expected to be useful especially because the spacecraft has been proverbially "running on empty" for a long time. Stardust has been in space for over 11 years and has flown past an asteroid (Annefrank), collected particle samples from a comet (Wild 2) and returned them to Earth in a sample return capsule in January 2006. Then, after these primary objectives, it was then re-tasked to perform a flyby of comet Tempel 1, a task it completed last month.

Before the burn to depletion Stardust pointed its antenna at Earth and sent information on the burn as it happened. The command ordering the rockets to fire was sent for 45 minutes, but the burn lasted just 146 seconds. 20 minutes after the engines burned out, Stardust's computer commanded its transmitters to turn off. Without fuel to power the spacecraft's attitude control system, Stardust's solar panels will not remain pointed at the sun. When this occurs, the spacecraft's batteries are expected to drain of power and deplete within hours.

Its a fitting end to a very impressive mission for NASA.

Jan
07
2011

Comet Temple 1
Comet Temple 1Courtesy NASA/JPL-Caltech/UMD
The following is from a listserv I am on that I thought was interesting.

On February 14, NASA's Stardust-NExT (New Exploration of Tempel 1) mission will encounter Comet Tempel 1, providing a unique opportunity to measure the dust properties of two separate comets (Wild 2 and Tempel 1) with the same instrument for accurate data comparison. The encounter will also provide a comparison between two observations of a single comet, Tempel 1, taken before and after a single orbital pass around the sun.

NASA's Stardust spacecraft will fly within 200 kilometers (about 124 miles) of Comet Tempel 1 on February 14, 2011, at about 8:36 p.m. Pacific Standard Time.

NASA's Deep Impact mission observed Comet Tempel 1 in the summer of 2005, as the comet was inbound toward the Sun on its approximately 5.5-year orbit between Mars and Jupiter. Deep Impact's primary mission was to deliver a special impactor spacecraft into the path of Comet Tempel 1. The spacecraft -- and many ground-based observers -- observed the impact and the ejected material. Scientists were surprised the cloud was composed of a fine, powdery material, not the expected water, ice, and dirt. The spacecraft did find the first evidence of surface ice on the surface of a comet instead of just inside a comet.

The Stardust-NExT mission is a low-cost use of an in-flight spacecraft redirected to a new target. Prior to its tasking for Tempel 1, the Stardust spacecraft successfully flew through the cloud of dust that surrounds the nucleus of comet Wild 2 in Jan. 2004. The particles of cometary material and gathered during this flyby were then returned to Earth aboard a sample return capsule which landed in the Utah desert in January 2006.


Stardust Capsule: Image courtesy NASA.
From Lawrence Livermore National Laboratory:

Contrary to expectations for a small icy body, much of the comet dust returned by the Stardust mission formed very close to the young sun and was altered from the solar system’s early materials.

When the Stardust mission returned to Earth with samples from the comet Wild 2 in 2006, scientists knew the material would provide new clues about the formation of our solar system, but they didn’t know exactly how.

New research by scientists at Lawrence Livermore National Laboratory and collaborators reveals that, in addition to containing material that formed very close to the young sun, the dust from Wild 2 also is missing ingredients that would be expected in comet dust. Surprisingly, the Wild 2 comet sample better resembles a meteorite from the asteroid belt rather than an ancient, unaltered comet.

More on this story here.

More on the Stardust/Wild 2 mission here.