CONTOUR COMET PROBE POSSIBLY DESTROYED
CONTOUR home page
Nederlands nieuws:
August 21, 2002
Six Days and Still No Signal
After six days, the Mission Operations team has yet to hear a signal
from the CONTOUR spacecraft.
Two objects, believed to be spacecraft segments, were detected Aug. 16, the day after the solid rocket motor burn, and a third more distant object has since been found. The objects are now more than 2 million kilometers from Earth, traveling at a steady 6.1 kilometers per second (3.8 miles per second or 13,600 miles per hour). They remain on a trajectory predicted by early observations; although they have now traveled so far from the Sun and Earth that more observations are unlikely.
If the spacecraft is still capable of operating, by Thursday, Aug. 22, it will have completed the first cycle of having each of its two transmitters attempt to send a signal through each of three antennas. Near continuous monitoring for CONTOUR continues through Sunday. After that, efforts will be scaled back to once a week - a schedule that will be maintained until early December when the spacecraft will come into a more favorable angle for receiving a signal from Earth. Deep Space Network coverage will extend through this weekend.
As far as contacting the spacecraft this week, Dr. Robert Farquhar, CONTOUR mission director from the Johns Hopkins Applied Physics Laboratory says, "We known there's not much room for optimism through this week. Even the second week of December, when we have our best shot, chances are small. But it's still worth monitoring."
August 19, 2002 -- 4:00 p.m. (EDT)
CONTOUR Team Listens For A Signal
With electronic eyes and ears pointed to the sky and a fix on CONTOUR's
location more than 1.3 million miles (2.1 million kilometers) from Earth,
the mission team continues checking for a signal from the spacecraft.
"The plan is to watch and monitor," says Mission Director Dr. Robert Farquhar of the Johns Hopkins University Applied Physics Laboratory, which built CONTOUR and manages the mission for NASA. "We realize the possibilities are small, but we can't discount the idea that the spacecraft is still operable. We have to determine that before we give up."
Since Friday the team has received telescope images from several observatories showing two objects traveling along CONTOUR's predicted path - which engineers believe is CONTOUR and part of the spacecraft that may have separated from it when CONTOUR's solid rocket motor fired on Aug. 15. Mission operators at APL and navigators at NASA's Jet Propulsion Laboratory are using these images to pinpoint the spacecraft's orbit and are aiming the Deep Space Network's powerful 70-meter and 34-meter antennas along that trajectory.
"Without knowing how big the objects in the telescope images are, we're going to work on the assumption that the spacecraft may still be largely intact," Farquhar says. "You need at least three separate observations to determine an orbit, and we have that. We know we're looking in the right place."
This week, mission operators are listening to determine if CONTOUR is alive and can carry out a timed command to cycle and attempt to transmit through three of its four antennas. The sequence is timed to start 96 hours after CONTOUR receives its last command. Because the team can't determine which commands the spacecraft may have received late last week, the cycling between transmitters and antennas could have started as early as 4:09 (EDT) this morning or could start as late as 10:09 (EDT) tonight.
The 60-hour sequence begins with the first of CONTOUR's two transmitters cycling 10 hours each through the low-gain and multidirectional (pancake) beam antennas on CONTOUR's aft side - opposite the dust shield - and the forward-side low-gain antenna. (Because of its narrow beamwidth and the unlikely prospect of its facing Earth, CONTOUR's high-gain dish antenna is not part of the sequence.) The second transmitter then repeats the pattern.
"It may be difficult to hear anything because, depending on the spacecraft's position and condition, the antennas might not have a direct line of sight toward Earth," says CONTOUR Mission Operations Manager Mark Holdridge. "But we'll be listening."
If the team doesn't hear from the spacecraft this week, Farquhar says, a final concentrated effort will be implemented in December when the antennas are in a more favorable orientation. "We're obligated to give it this last try," he says. "And who knows, we might get lucky."
SpaceRef.com
16 August 2002
Spacewatch Telescope May Have Spotted CONTOUR Debris
In this subtracted image in which moving objects are revealed by pairs of images,
one dark and one bright, taken by Jim Scotti with the Spacewatch 1.8-meter telescope
on Kitt Peak on 2002 August 16, there are two parallel trails near one of the predicted
positions of the CONTOUR spacecraft, radio contact with which had been lost the day
before following a commanded large velocity impulse maneuver.
August 16, 2002 -- 05:59 pm ET
Comet-Chasing Spacecraft Possibly Destroyed, NASA Says
The comet-chasing CONTOUR spacecraft appears to have broken into two pieces sometime after its course-altering rocket engine fired early yesterday morning, a NASA official said Friday evening.
A ground-based telescope photograph of two unknown objects about 155 miles (250 kilometers) apart appeared to be pieces of CONTOUR (Comet Nucleus Tour). The objects were spotted along the path the spacecraft would have traveled had the engine fired.
Spaceflight Now
August 16, 2002
CONTOUR comet probe may have broken up in flight
A telescope operated by the Spacewatch asteroid detection program has photographed two
objects beyond the orbit of the moon that may be the remains of NASA's CONTOUR comet
probe. While engineers have not yet confirmed the objects are, in fact, pieces of
the $159 million CONTOUR, mission director Robert Farhquar said "I'm not very optimistic."
August 16, 2002 -- 9:30 p.m. (EDT)
Next Operations: Radar and Radio Checks
Efforts to locate the CONTOUR spacecraft – through a series of telescope, radar and radio checks – are expected to continue through the weekend. On Monday, Aug. 19, mission operators plan to check if CONTOUR automatically carries out a built in command to cycle through and transmit through all four of its antennas. The sequence is programmed to begin 96 hours after CONTOUR receives its last command -- meaning it could start as early as 4:09 a.m. (EDT) or as late as 10:09 p.m. Monday -- and would last several hours.
“We aren’t sure that the spacecraft is completely gone, and that’s what we’re going to be working on over the next several days,” says Dr. Robert Farquhar, CONTOUR mission director from the Johns Hopkins University Applied Physics Laboratory, which built the CONTOUR spacecraft and manages the mission for NASA.
August 16, 2002 -- 1 p.m. (EDT)
Search for CONTOUR Continues
Mission operators continue to listen for a signal from CONTOUR.
Using its 34-meter antennas, NASA's Deep Space Network stations are scanning the spacecraft's expected path beyond Earth's orbit, attempting to pick up radio signals from CONTOUR's transmitters. The CONTOUR team is also awaiting feedback from several NASA-sponsored and other optical and radar sites that have been searching the skies for signs of the spacecraft.
CONTOUR's STAR 30 solid-propellant rocket motor was programmed to ignite at 4:49 a.m. EDT on Aug 15, boosting the spacecraft out of an Earth parking orbit and onto a trajectory to encounter two comets over the next four years. The spacecraft was too low for DSN antennas to track it during the burn - about 140 miles (225 kilometers) above the Indian Ocean - and the CONTOUR mission operations team at the Johns Hopkins University Applied Physics Laboratory expected to regain contact about 45 minutes later to confirm the burn. No signal was received, and the team has been working through plans to find the craft along the predicted trajectories for a successful burn.
CONTOUR's onboard computer was carrying a command that, starting at 6 a.m. EDT today, would have turned the spacecraft and pointed another of its four antennas toward Earth. So far, however, no signal has been received.
August 15, 2002 -- 7:30 p.m. EDT
CONTOUR Contact Attempts Continue
Mission operators continue to scan the skies for the CONTOUR spacecraft, working through a list of strategies for re-establishing contact with the solar-powered probe through NASA's Deep Space Network (DSN).
"We're still trying to get a telemetry link," says CONTOUR Mission Director Dr. Robert Farquhar, of the Johns Hopkins University Applied Physics Laboratory, Laurel, Md. "We're trying to send commands to spacecraft to switch between its two transmitters and use different on-board antennas, in case they turned off for some reason. But we really won't know what happened until we contact it."
CONTOUR's STAR 30 solid-propellant rocket motor was programmed to ignite at 4:49 a.m. EDT and deliver a 1,920 meter-per-second boost that would send CONTOUR out of Earth's orbit and onto a path that would eventually take it past two comets. At about 140 miles (225 kilometers) above the Indian Ocean, the spacecraft was too low for DSN antennas to track it at the scheduled time of the burn. NASA's Jet Propulsion Laboratory, Pasadena, Calif, operates the DSN.
The CONTOUR mission operations team at the Johns Hopkins University Applied Physics Laboratory expected to regain contact at approximately 5:35 a.m. EDT to confirm the burn. When no signal was received, the team immediately began working through backup plans to re-establish contact, searching along the predicted trajectories for a successful burn.
"We're looking at the nominal path, as if the burn occurred," Farquhar says. "We're working on the assumption that the motor fired, and the team is putting its priority there."
CONTOUR's on-board computer is also carrying a command that, about 24 hours after the scheduled burn time, would turn the craft about 40 degrees and perhaps improve its antennas' fix on Earth. Farquhar adds that without knowing CONTOUR's status, it is difficult to know what commands it can, or did, execute. Still, he says, "we're cautiously optimistic that we will find the spacecraft."
CONTOUR, a Discovery-class mission to explore the nucleus of comets, was built and managed by the John Hopkins Laboratory Applied Physics Laboratory, Laurel, Md., for NASA.
August 15, 2002 -- 03:30 pm ET
Amateur and Professional Astronomers Search the Skies for Quiet CONTOUR
Mission managers are racing against a Friday night deadline to find the missing CONTOUR spacecraft and make sure it's on its way to deep space. They're hoping the craft might be spotted by an unofficial network of amateur and professional telescopes around the world, SPACE.com has learned.
The NASA spacecraft has not contacted ground control since a scheduled engine burn at 4:49 a.m. EDT that would have propelled it out of Earth orbit.
As of 2:50 p.m. EDT, no one knew whether CONTOUR was still orbiting Earth or was heading off on its mission. There was no indication whether the burn occurred as planned or not.
August 15, 2002
Controllers looking for CONTOUR comet probe
In a crucial event for NASA's $159 million CONTOUR mission, a solid-fuel kick motor
on the spacecraft was supposed to fire Thursday to propel the probe out of Earth orbit
and into solar orbit for the journey to ultimately intercept at least two comets. The
maneuver, scheduled at 4:49 a.m. EDT about 140 miles above the Indian Ocean, was to
occur while the craft was out of contact with the ground. Communications were to be
regained by 5:35 a.m. EDT, but as of Thursday evening officials were still searching
to hear the craft's signal.
Aug 15, 2002
NASA Remains Hopeful of Finding CONTOUR Spacecraft
NASA officials said Thursday evening they remain hopeful of finding the Comet Nucleus Tour (CONTOUR) spacecraft, missing since a scheduled maneuver early in the morning that would have sent the probe out of Earth's orbit onto a path to encounter multiple comets.
Aug 15, 2002
Comet Mission Missing In Orbit
Mission operators are looking for a signal from Contour, several hours after
a scheduled maneuver to send the spacecraft from Earth's orbit onto a path to
encounter multiple comets.
NASA
Johns Hopkins University
Cornell University
August 15, 2002 -- 1 PM EDT
Mission Operations Awaiting Contact from CONTOUR Spacecraft
Mission operators are looking for a signal from CONTOUR, several
hours after a scheduled maneuver to send the spacecraft from
Earth's orbit onto a path to encounter multiple comets.
CONTOUR's STAR 30 solid-propellant rocket motor was programmed to ignite at 4:49 a.m. EDT and deliver 1,920 meter-per-second boost which CONTOUR needed to escape Earth's orbit. At about 140 miles (225 kilometers) above the Indian Ocean, the spacecraft was too low for NASA's Deep Space Network (DSN) antennas to track it at the scheduled time of the burn.
The CONTOUR mission operations team at the Johns Hopkins University Applied Physics Laboratory expected to regain contact at approximately 5:35 a.m. EDT to confirm the burn, but by 9 a.m. EDT the DSN had not acquired a signal.
The mission operations team is working through several backup plans to establish contact with the spacecraft, searching along the predicted trajectories for a successful burn.
CONTOUR, a Discovery-class mission to explore the nucleus of comets, was built and managed by the John Hopkins Laboratory Applied Physics Laboratory, Laurel, Md., for NASA.
July 3, 2002
Probe launched to see fossils from formation of planets
A tiny space probe was dispatched from Earth this morning for a tantalizing tour of comets -- the frozen time capsules that hold the primordial building blocks left over from the creation of our solar system.
The $159 million Comet Nucleus Tour mission, dubbed CONTOUR, will encounter at least two comets to give scientists their closest look at the hearts of these dirty snowballs.
NASA Headquarters, Washington, DC
February 15, 2000
NASA BEGINS BUILDING NEXT MISSION TO STUDY COMETS
NASA's Comet Nucleus Tour, or CONTOUR, mission this month
took a giant step closer to its launch when the project received
approval to begin building the spacecraft.
Planned for a July 2002 launch, CONTOUR is expected to encounter Comet Encke in November 2003 and Comet Schwassmann- Wachmann-3 in June 2006. The mission has the flexibility to include a flyby of Comet d'Arrest in 2008 or an as-yet undiscovered comet, perhaps originating from beyond the orbit of Pluto. Such an unforeseen cometary visitor to the inner solar system, like Comet Hale-Bopp discovered in 1995, would present a rare opportunity to conduct a close-up examination of these mysterious, ancient objects which normally reside in the cold depths of interstellar space.
The nucleus of a comet is its heart, believed by scientists to be a tiny irregular chunk of ice and rock. To date only one comet nucleus has ever been viewed by a spacecraft: Comet Halley in 1986. CONTOUR will fly past at least two comets and take higher resolution images than those of Halley. It will also collect and analyze gas and dust to reveal the comet's makeup, greatly improving our knowledge of key characteristics of comet nuclei and providing an assessment of their diversity. CONTOUR also will clear up the many mysteries of how comets evolve as they approach the Sun and their ices begin to evaporate.
The CONTOUR spacecraft will fly by each comet at the peak of its activity when it's close to the Sun. During each encounter, the target comet will also be well situated in the night sky for astronomers worldwide to make concurrent observations from the ground. The spacecraft will fly by each comet at a distance of about 60 miles (100 kilometers).
After successful completion of both the Preliminary Design
Review and an independent Confirmation Assessment and the
Confirmation Review at NASA Headquarters, the comet flyby project
is well on its way toward completing the spacecraft design. The
CONTOUR mission is managed for NASA by the Johns Hopkins
University Applied Physics Laboratory, in Laurel, MD. The
Principal Investigator is Dr. Joseph Veverka of Cornell
University, NY. More information on CONTOUR is available at:
www.contour2002.org and
www.discovery.nasa.gov.
Cornell University
NASA gives go-ahead to Cornell-led 2002 mission to explore comets<
Feb. 16, 2000
ITHACA, N.Y. -- NASA has given the go-ahead for the Cornell University-led
Comet Nucleus Tour, or Contour, mission. The agency said the mission has
passed a critical review and the building of the spacecraft can begin.
Cornell will lead and direct the $158 million mission to conduct close-proximity comet flybys. The spacecraft is scheduled for launch in July 2002, with the precise launch date to be decided in the next year or two.
The principal investigator on the mission is Joseph Veverka, professor of astronomy at Cornell and chair of the astronomy department. Other Cornell researchers on the team are Steven W. Squyres, professor of astronomy, who will interpret the geology of the comets; James Bell, assistant professor of astronomy, who will interpret the spectral maps of the comets; and Peter C. Thomas, senior research associate, who is a leading expert in determining the size and shape of irregular objects like comets.
David Jarrett of NASA's Discovery Program, said, "After successful completion of both the preliminary design review and an independent confirmation assessment, the Contour team is well on its way toward completing the spacecraft design."
The launching of Contour is timed to encounter and study Comet Encke in November 2003 and Comet Schwassmann-Wachmann-3 in June 2006. The mission has the flexibility to include a flyby of Comet d'Arrest in 2008 or to retarget itself to approach an unforeseen cometary visitor to the inner solar system. Mission scientists are hopeful they will have the opportunity to study a newly discovered comet, such as Comet Hale-Bopp, which was discovered by amateur astronomers in 1995.
The spacecraft, to be launched aboard a Delta rocket, will be outfitted with a solar array for power and a high-gain antenna for communication with Earth. The Contour spacecraft will venture about 30 million miles from Earth to study the comets. Building of the spacecraft at the Applied Physics Laboratory at Johns Hopkins University, which is managing the mission, begins this month.
The nucleus of a comet is its heart, believed by scientists to be a tiny, irregular chunk of ice and rock. To date only one comet nucleus has ever been viewed with a spacecraft: Comet Halley in 1986. The spacecraft will fly past at least two comets and take far better pictures than those of Halley. It will also collect and analyze dust to reveal the comet's makeup, greatly improving our knowledge of key characteristics of comet nuclei and providing an assessment of their diversity.
The mission also will clear up the many mysteries of how comets evolve as they approach the Sun and their ices begin to evaporate.
The spacecraft will fly by each comet at the peak of its activity, close to the Sun. During each encounter, the target comet will also be well situated in the night sky for astronomers worldwide to make concurrent observations from the ground. The spacecraft will fly by each comet at a distance of about 100 kilometers (62 miles).
Related World Wide Web sites: The following sites provide additional information on this news release. Some might not be part of the Cornell University community, and Cornell has no control over their content or availability.
Back to ASTRONET's home page
Terug naar ASTRONET's home page