Stardust NExT Targets Valentines Day Encounter with Comet Tempel 1

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After a more than decade long journey of 6 billion kilometers, hopes are high for a celestial date in space between an icy comet and a thrusting probe on Valentine’s Day 2011. The rendezvous in space between NASA’s approaching Stardust-NExT spacecraft and Comet Tempel 1 takes place nearly on the exact opposite side of the Sun on Feb 14, 2011 at approximately 11:37 p.m. EST (8:37 p.m. PST).

The top science goal is to find out “how much the comet’s surface has changed between two close passages to the sun” since it was last visited in 2005, said principal investigator Joe Veverka of Cornell University, Ithaca, N,Y at a media briefing today, Jan 19, at NASA Headquarters. Indeed it’s the first time in history that a comet has been visited twice by space probes from Earth.

The lead scientists and engineers outlined the plans for the cometary flyby at the briefing. See a video of the entire briefing below.


Since the last visit in 2005, the comet has completed another orbit around the sun. “It will be the first time we’ll be able to see changes after a comet has passed through one perihelion,” explained Veverka. Tempel 1 belongs to the Jupiter family of comets and orbits between Mars and Jupiter.


Comet Tempel 1 suffered a cosmic collision during that first encounter with an emissary from Earth when NASA’s Deep Impact smashed a copper projectile directly into the comets nucleus. The blast created an impact crater and ejected an enormous cloud of gas and debris. Reflected light off the dust particles totally obscured the view of the crater and prevented any images from being taken. Researchers had hoped to determine the size of the crater. A lot of bets hinge on that determination.

“We have a chance to complete the Deep Impact experiment. We hope to see how big the impact crater is and what that tells us about the mechanical properties, ” said Veverka.

20 Jan. 2011 Position of STARDUST-NExT probe - Looking Down on the Sun.
This image shows the current position of the STARDUST-NExT spacecraft and the spacecraft's trajectory (in blue) around the Sun. Credit: NASA

With just over 3 weeks remaining, the craft is approximately 24.6 million kilometers (15.3 million miles) away from its encounter. Stardust-NExT will zoom past the nearly 6-kilometer-wide comet (3.7 miles) at a distance of approximately 200 kilometers (124 miles) and at a speed of 10 km/sec according to Tim Larson, the mission’s project manager from the Jet Propulsion Laboratory (JPL), Pasadena, Calif.

“The spacecraft is still working well 12 years after launch. This is a bonus mission with a scientifically desirable target which we can get close to,” said Larson.

“Everything will happen autonomously,” stated Larson. “The craft will be about 2 AU away from Earth at encounter. Since the round trip signals will take about 40 minutes there is no chance for any real time changes.”

Different features on Tempel 1 discovered by Deep Imapct in 2005. Credit: NASA

“Stardust-NExT will take 72 high resolution images during the close approach encounter. These will be stored in an onboard computer and relayed back to Earth starting about an hour later. It will take about 12 hours to get them all back.”

NASA says that after processing, the images are expected to be available at approximately 4:30 a.m. EST (1:30 a.m. PST) on Feb. 15.

“For the first time we’ll go back to see what happens to a comet since our last visit,” explained Pete Schultz, co-investigator of Brown University, Providence, R.I. “The comet has been out to the orbit of Jupiter and back to Mars and had several outbursts of gas and dust. In 2005 we saw old and new surfaces. So it has a complicated geologic history. We hope to resolve the crater and see ejecta. But there are many unknowns. What we see – whether its the crater or the other unseen side – all depends on the rotation of the comet nucleus.”

“The comet dynamics are complex and erratic, not inert,” said Steve Chesley, a co-investigator at JPL. “They are like a rocket with no one at the controls. The orbit can change. So it is a huge challenge to target a spacecraft for a flyby or rendezvous.”

Stardust successful original mission was to fly by Comet Wild 2 on Jan 2, 2004. It then returned cometary dust particle in a sample return canister to Earth on Jan. 19, 2006 which reentered the atmosphere at the highest speed ever and parachuted to a safe landing. Credit: NASA

Stardust-NeXT is a repurposed spacecraft. The Valentine’s Day encounter will be the last hurrah for the aging probe. Stardust was originally launched way back in 1999. It flew by Comet Wild 2 on Jan. 2, 2004 and collected cometary dust particles which were returned to Earth in a sample return capsule in Jan. 2006. Since then it has continued its solitary voyage through the void of the space.

The craft is nearly out of fuel and all movements consume fuel. It is totally dependent on the reaction control thrusters for navigating through space and pointing its camera and science instruments, said Larson.

“We are confident that we will have enough fuel to finish up this mission. It has been a big, big challenge to maintain a reserve supply. After the mission there won’t be much left that the spacecraft can do. The last trajectory correction maneuver is two days before arrival. That is also when we will take our last optical navigation images for targeting the spacecraft.”
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Only about a third of the surface of Tempel 1 was photographed by Deep Impact in 2005. “We’ll be looking at old territory and new and some overlap,” explained Veverka. “The science team is awfully excited and just can’t wait to see the pictures on Valentine’s day.”

“We have no idea how quickly the surface features change and whether its millions of years or days,” concluded Veverka.

“We expect new discoveries no matter what we see,” Larson summed up

Stardust-NExT Spacecraft & Comet Tempel 1. Artist rendering of Stardust-NExT spacecraft nearing Comet Tempel 1 for upcoming flyby on February, 14, 2011. Credit: NASA
See video and graphics below of Jan 19, 2011 Media briefing from the Science Team about plans for the cometary encounter
Planned imaging of Comet Tempel 1 by Stardust-NExT during flyby. Blue area is unseen and unmapped territory never imaged by Deep Impact during 2005 flyby. Bulls eye in yellow area is expected location of 2005 impact crater and expected new coverage. There is some overlap. Credit: NASA
Planned imaging of Comet Tempel 1 by Stardust-NExT during flyby. Blue area is unseen and unmapped territory never imaged by Deep Impact during 2005 flyby. Credit: NASA

Jan. 19, 2010: Science Team Media Briefing

The Stardust spacecraft has been repackaged for the Stardust-NexT mission. Stardust-NExT will rendezvous with Comet Tempel 1 on February 14, giving scientists an opportunity, for the first time, to search a comet’s surface for changes following its orbit around the sun. Mission scientists discussed the relevance of the mission at a briefing at NASA headquarters in Washington

Stardust successful original mission was to fly by Comet Wild 2 on Jan 2, 2004 and return cometary dust particle to earth in Jan. 2006. It is equipped with 3 science instruments. Credit: NASA

35 Days to STARDUST-NeXT Valentines Day Flyby of Comet Tempel 1

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35 Days and Counting !

NASA’s re-purposed STARDUST- NeXT spacecraft is set to flyby Comet Tempel 1 at a distance of just 200 km on Valentine’s Day – February 14, 2011 at about 8:36 p.m. PST. The encounter marks the first time that a comet has been visited twice by probes from Earth. The revisit also provides the first opportunity for up-close observations of a comet both before and after a single orbital pass around the sun.

Comet Tempel 1 was first visited by NASA’s Deep Impact comet smashing mission in July 2005. Deep Impact delivered a 375 kg projectile into the path of Temple 1 that resulted in a high speed impact directly into the comet nucleus.

The cosmic collision of about 10.2 km/sec (22,800 miles/hour) ejected a cloud of debris that was studied by the Deep Impact spacecraft as well as an armada of orbiting and ground based telescopes. The impact crater itself was obscured by the debris cloud. The spacecraft did find the first evidence of surface ice on a comet instead of just inside a comet. Stardust NExT will take images and spectra of Tempel 1 and hunt for the impact crater.

Artists concept of NASA’s STARDUST- NeXT probe which will fly by Comet Tempel 1 on Feb. 14, 2011. Credit: NASA

According to the latest update posted at the STARDUST- NeXT mission website on Jan 6; “The spacecraft is healthy and began the New Year with a cold boot to clear a memory address latch-up that had occurred late in 2010. This cold boot clears the latched line and resets the memory to its factory settings.”

The reboot was completely successful and sets the probe up to accomplish the missions science objectives. On board optical navigation cameras were scheduled to take a new set of images on Jan. 6.

The update further states that the mission plan has now changed substantially to accommodate two new challenges. First the estimated fuel remaining on board is lower than expected. Second, the optical navigation cameras failed to detect the comet in the prior set of images in December.

10 Jan. 2011 Position of STARDUST-NeXT probe - Looking Down on the Sun. This image shows the current position of the STARDUST spacecraft and the spacecraft's trajectory (in blue) around the Sun. Credit: NASA

The optical cameras provide the key information to precisely navigate the probe to the comet. “Current estimates show that the comet may not be bright enough to detect with the Navcam until the latter half of January,” states the update.

As a result of the lower fuel estimate the remaining trajectory maneuvers (TCM’s) have been adjusted to January 31, February 7, and February 12. No science images will be taken until the last 7 days prior to the Feb 14 encounter.

Caption: Video of Comet Tempel 1 as NASA’s Deep Impact comet spacecraft delivers a projectile which smashed into the comet in July 2005. NASA’s STARDUST- NeXT probe is set to flyby Comet Tempel 1 on February, 14, 2011. The probe will collect numerous high resolution images of the coma and nucleus and hunt for the elusive 2005 impact crater.

The team states that these changes will provide “positive fuel margin through encounter …. and places the TCMs at times best able to accommodate late detection of the comet”.

The engineering team is building new approach sequences to accommodate these significant changes to the approach and Comet Tempel 1 encounter on Feb 14.

A briefing by the science team will be carried live on NASA TV on Jan. 19 at 2 PM EST

The Stardust spacecraft accomplished its original goal of flying through a dust cloud surrounding the nucleus of comet Wild 2 in Jan. 2004. The probe successfully gathered particles of cometary material during the flyby, The comet particles were returned to Earth aboard a sample return capsule which landed in the Utah desert in January 2006.

Comet particle tracks in aerogel returned to Earth by STARDUST in January 2006