Stardust-NExT sees Jets and impact crater at Comet Tempel 1 and says Farewell !

by Ken Kremer on March 24, 2011

Stardust-NExT enhanced image of Jets from Comet Tempel 1
Stardust-NExT photographed jets of gas and particles streaming from Comet Tempel 1 during Feb 14, 2011 flyby. The raw image was taken 15 seconds before closest approach at a distance of 244 kilometers, and has been extensively enhanced by outside analysts to visibly show the jets. Annotations show the location of the jets and the crater created by a projectile hurled by NASA’s prior Deep Impact mission in 2005. Credit: NASA/JPL-Caltech/University of Maryland/Post process and annotations by Marco Di Lorenzo/Kenneth Kremer
Poster below shows the changing view of the comets surface and
the deep impact crater during the course of the Tempel 1 flyby

Farewell Stardust-NExT !

Today marks the end to the final chapter in the illustrious saga of NASA’s Stardust-NExT spacecraft, a groundbreaking mission of cometary exploration.

Mission controllers at NASA’s Jet Propulsion Laboratory commanded the probe to fire the main engines for the very last time today at about 7 p.m. EDT (March 24). The burn will continue until the spacecraft entirely depletes the tiny amount of residual fuel remaining in the propellant tanks. The Stardust probe is now being decommissioned and is about 312 million kilometers away from Earth.

This action will effectively end the life of the storied comet hunter, which has flown past an asteroid (Annefrank), two comets (Wild 2 and Tempel 1) and also returned the first ever pristine samples of a comet to Earth for high powered analysis by the most advanced science instruments available to researchers.

NASA’s Stardust space probe completed her amazing science journey on Feb. 14, 2011 by streaking past Comet Tempel 1 at 10.9 km/sec, or 24,000 MPH and successfully sending back 72 high resolution images of the comets nucleus and other valuable science data. Tempel 1 became the first comet to be visited twice by spacecraft from Earth.

During the Feb. 14, 2011 flyby of Comet Tempel 1, Stardust-NExT discovered the man-made crater created back in 2005 by NASA’s Deep Impact mission and also imaged gas jets eminating from the comet. My imaging partner Marco Di Lorenzo and myself prepared two posters illustrating the finding of the jets and the Deep Impact crater included in this article.

6 Views of Comet Tempel 1 and Deep Impact crater from Stardust-NExT spacecraft flyby on Feb. 14, 2011. Arrows show location of man-made crater created in 2005 by NASA’s prior Deep Impact comet smashing mission and newly imaged as Stardust-NExT zoomed past comet in 2011.
The images progress in time during closest approach to comet beginning at upper left and moving clockwise to lower left. Credit: NASA/JPL-Caltech/University of Maryland/Post process and annotations by Marco Di Lorenzo/Kenneth Kremer

The rocket burn will be the last of some 2 million rocket firings all told since the Stardust spacecraft was launched back in 1999. Over a dozen years, Stardust has executed 40 major flight path maneuvers and traveled nearly 6 billion kilometers.

The rocket firing also serves another purpose as a quite valuable final contribution to science. Since there is no fuel gauge on board or precise method for exactly determining the quantity of remaining fuel, the firing will tell the engineers how much fuel actually remains on board.

To date the team has relied on several analytical methods to estimate the residual fuel. Comparing the results of the actual firing experiment to the calculations derived from estimates will aid future missions in determining a more accurate estimation of fuel consumption and reserves.

“We call it a ‘burn to depletion,’ and that is pretty much what we’re doing – firing our rockets until there is nothing left in the tank,” said Stardust-NExT project manager Tim Larson of NASA’s Jet Propulsion Laboratory in Pasadena, Calif in a statement. “It’s a unique way for an interplanetary spacecraft to go out. Essentially, Stardust will be providing us useful information to the very end.”

Just prior to the burn, Stardust will turn its medium gain antenna towards Earth and transmit the final telemetry in real time. Stardust is being commanded to fire the thrusters for 45 minutes but the team expects that there is only enough fuel to actually fire for up to perhaps around ten minutes.

On March 24, at about 4 p.m. PDT, four rocket motors on NASA's Stardust spacecraft, illustrated in this artist's concept, are scheduled to fire until the spacecraft's fuel is depleted. Image credit: NASA/JPL-Caltech

As its final act, the transmitters will be turned off (to prevent accidental transmissions to other spacecraft), all communications will cease and that will be the end of Stardust’s life.

With no more fuel available, the probe cannot maintain attitude control, power its solar array or point its antenna. And its far enough away from any targets that there are no issues related to planetary protection requirements.

“I think this is a fitting end for Stardust. It’s going down swinging,” Larson stated in the press release.

Stardust-NExT website

Read more about the Stardust-NExT Flyby and mission in my earlier stories here, here, here, here, here, here and here

Relive the Feb. 14 Flyby of Comet Tempel 1 in this movie of NASA/JPL images

Stardust-NExT: 2 Comet Flybys with 1 Spacecraft.
Stardust-NExT made history on Valentine’s Day - February, 14, 2011 – Tempel 1 is the first comet to be visited twice by spacrecraft from Earth. Stardust has now successfully visited 2 comets and gathered science data: Comet Wild 2 in 2004 (left) and Comet Tempel 1 in 2011 (right).
Artist renderings Credit: NASA. Collage: Ken Kremer.

Stardust-NExT location on March 11, 2011 just prior to farewell transmission. Credit: NASA/JPL

About 

Dr. Ken Kremer is a speaker, scientist, freelance science journalist (Princeton, NJ) and photographer whose articles, space exploration images and Mars mosaics have appeared in magazines, books, websites and calanders including Astronomy Picture of the Day, NBC, BBC, SPACE.com, Spaceflight Now and the covers of Aviation Week & Space Technology, Spaceflight and the Explorers Club magazines. Ken has presented at numerous educational institutions, civic & religious organizations, museums and astronomy clubs. Ken has reported first hand from the Kennedy Space Center, Cape Canaveral and NASA Wallops on over 40 launches including 8 shuttle launches. He lectures on both Human and Robotic spaceflight - www.kenkremer.com. Follow Ken on Facebook and Twitter

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