January 29, 2015
Dawn Approaching Ceres and Seeing the Sights
Dawn is now flying its approach trajectory to Ceres. The spacecraft is twice as close to Ceres as the moon is to Earth and slowly getting even closer as it prepared to enter orbit. Dawn halted ion thrusting twice this month to take pictures of the dwarf planet for use in navigation. These tantalizing glimpses are already raising expectations for an exciting mission there, and they will be followed by even better views next month. This month's Dawn Journal gives the plan for photographing Ceres throughout the rest of the approach phase.
December 29, 2014
Dawn Thrusting on Opposite Side of the Sun
Dawn devoted November to ion thrusting, and it is now about three times as far from Ceres as the moon is from Earth. As Earth and Dawn follow their separate orbits around the sun, they are moving to opposite sides of the solar system's star. To learn how to use the sun to locate Dawn early in December, see the November Dawn Journal, which also describes the new route the spacecraft will take into orbit around the dwarf planet.
October 31, 2014
As the spacecraft continues ion thrusting to reshape its orbit around the sun to match Ceres' orbit, it is moving ever closer to the dwarf planet. At the end of this month, Dawn is about 1.3 million miles (2.1 million kilometers) from Ceres, closing in at less than 900 mph (0.4 kilometers per second). It is on course for arriving in orbit in early March 2015. A summary of the schedule for photographing Ceres during the approach phase in January and
Dawn Continues Smoothly ToFebruary is in the October Dawn Journal, and a more detailed description will be presented in November.
September 27, 2014
Seven Years and Going Strong
On the seventh anniversary of its launch, Dawn's mission is continuing to go well. As it thrusts with its ion propulsion system, it is now less than 10 times farther from Ceres than Earth is from the moon.
Dawn has thrust for 68 percent of the time it has been in space (1,741 days), effectively changing its speed by 22,800 mph (10.2 kilometers per second). All this thrusting has consumed only 808 pounds (367 kilograms) of xenon propellant. For more details on the progress it has made in seven years of its deep-space adventure, see the latest Dawn Journal.
Earlier in the month, on Sep. 11, a high-energy particle of radiation struck an electrical component, causing the ion thrust to stop. The operations team guided the spacecraft back to normal operations, and ion thrusting resumed on Sep. 15. The October Dawn Journal will detail what occurred on the spacecraft, how the team dealt with it, and how the interruption in thrusting will change the approach phase of the Ceres mission. (The plan for scrutinizing Ceres from a series of progressively lower orbits will not change.)
August 31, 2014
Another Month of Ion Thrusting Complete
The spacecraft has completed another month of ion thrusting, bringing it ever closer to its rendezvous with Ceres. Dawn is now 3.0 million miles (4.8 million kilometers) from Ceres and approaching it at less than 1500 mph (2400 kilometers per hour). Dawn's fourth and final phase of orbital observations will be at 230 miles (375 kilometers) above the dwarf planet's surface. The three month low altitude mapping orbit is previewed in the August Dawn Journal, along with a brief look at what might happen after the conclusion of the planned mission.
July 31, 2014
Spacecraft Cruising Smoothly; Mission Control Simulates Problems
Dawn is propelling itself to Ceres with ion engine #1, which was not used from January 2010 until May 2014. Engineers verified that all the sensors the probe will use to explore Ceres are healthy. While the mission continues smoothly, the control team simulated dealing with a host of problems on the distant spacecraft. The July Dawn Journal provides an update on activities on the spacecraft and in mission control.
June 30, 2014
Dawn's Deep Space Voyage Going Well
With another month of ion thrusting complete, Dawn's interplanetary journey to Ceres continues to go well. It will spend about two months at an altitude of 910 miles (1,40 kilometers) for the third orbital phase of its exploration of the alien world. For a preview, read the June Dawn Journal.
May 31, 2014
Dawn's Journey Continuing Smoothly
The spacecraft devoted most of May to more gentle ion thrusting, bringing it ever closer to its rendezvous with dwarf planet Ceres. Dawn's second orbital phase around the dwarf planet will be at an altitude of 2,730 miles (4,400 kilometers). The May Dawn Journal presents a preview of this “survey orbit.”
April 30, 2014
Dawn Less than One Year from Ceres
Dawn is making good progress on its journey to Ceres and is now less than a year from arrival. To perform all of its planned observations, it will take advantage of the remarkable capability of its ion propulsion system by maneuvering extensively in orbit to provide different perspectives.The April Dawn Journal explains how the ship will spiral down to lower and lower altitudes above the alien landscapes.
March 31, 2014
Dawn Nearing Earth as It Climbs to Ceres
As Dawn continues its ion thrusting to reach Ceres, the independent orbits the spacecraft and Earth follow are about to bring them to their closest point since 2011. They will never be this near each other again, although Dawn is still farther from Earth than the sun is. To learn more about this intriguing orbital choreography, visit the March Dawn Journal.
February 28, 2014
Dawn on Course and on Schedule as Ion Thrusting Continues
Dawn has completed another month of ion thrusting toward Ceres. After it is captured by Ceres's gravity early next year, it will continue descending to an altitude of 8,400 miles (13,500 kilometers) for its first intensive observations. Continuing the preview of the explorer's mission at the dwarf planet, the February Dawn Journal explains what the spacecraft will do during that orbit phase.
January 31, 2014
Dawn Continues Spiraling to Ceres
Dawn continues its spiral outward from the sun, heading for Ceres. The spacecraft is gradually changing its orbit so that it matches Ceres's orbit around the sun. In a little more than a year, this will allow the probe to be captured by the dwarf planet's gravity. Thanks to its ion propulsion system, Dawn's gentle, graceful entry into orbit is very different from the tense, whiplash-inducing method used by conventional missions. To learn more, visit the latest Dawn Journal for the second in a series of previews of how the ship will accomplish its ambitious mission at the alien world of rock and ice.
December 31, 2013
Dawn More than Halfway from Vesta to Ceres
Dawn resumed ion thrusting early this month and ends 2013 by continuing to thrust toward its 2015 rendezvous with the dwarf planet ahead. The spacecraft is now closer to Ceres than to Vesta. For the first in a series of previews of what the probe will do when it reaches the mysterious alien world, visit the latest Dawn Journal.
November 30, 2013
Dawn Accomplishes Special Assignments While Coasting to Ceres
Dawn is in an unusual part of its interplanetary trajectory during which coasting is preferable to ion thrusting. Engineers took advantage of this period to operate in a new "hybrid" mode, in which the spacecraft uses its two healthy reaction wheels plus its hydrazine-powered jets to control its orientation in space. This successful test paves the way for using hybrid when Dawn is in its lowest orbits at Ceres, where the system may extend the limited supply of hydrazine. Mission controllers also confirmed the health of the sensors that will investigate Ceres. Visit the Dawn Journal for details on Dawn's latest activities and intriguing milestones the spacecraft will pass in December.
October 31, 2013
Dawn Plans a Hiatus in Ion Thrusting
Dawn completed another month of ion thrusting and is making excellent progress to Ceres.
Although a great deal of thrusting is required to reach its destinations in the main asteroid belt, the flight plan requires Dawn to coast soon for four weeks. See the latest Dawn Journal for details.
September 27, 2013
Dawn Completes Sixth Year of Flight
Dawn celebrated its sixth anniversary of spaceflight by continuing to thrust with its ion propulsion system on the long journey from Vesta to Ceres, just as it has most of the last year.
The probe has thrust for 1,410 days so far in the mission, or 64 percent of the time since launch. Its effective change in speed is more than 8.7 kilometers per second (19,500 miles per hour), well in excess of what any other spacecraft has achieved under its own power. Thanks to the efficiency of the ion propulsion system, all this thrusting has consumed only 318 kilograms (701 pounds) of xenon propellant.
To see more about the spacecraft's progress in six years of interplanetary flight, visit the latest Dawn Journal.
August 30, 2013
Dawn and Earth on Opposite Sides of the Sun
As Dawn travels through the main asteroid belt independently of Earth's motion around the sun, the spacecraft and planet were on opposite sides of the solar system's star this month. Dawn was well in excess of one million times farther from Earth than the International Space Station. Visit the August Dawn Journal to read more about this extraordinary alignment.
July 29, 2013
As Spacecraft Continues to Ceres, Engineers Test Its Solar Array
Dawn continues to thrust with its power-hungry ion propulsion system to rendezvous with dwarf planet Ceres in 2015. To keep the spacecraft on course and on schedule, engineers need an accurate prediction of how much electrical power its solar arrays will generate as it recedes from the sun. The probe recently conducted a special test in which it rotated its huge wings so they would experience the same illumination they will receive later in this deep-space mission. For more information on why Dawn craves power and how this activity was performed, visit the July Dawn Journal.
June 30, 2013
Dawn Sailing Smoothly With a Different Ion Engine
After relying on ion engine #3 since August 2011, engineers decided to command #2 to take over this month, and the ship is continuing to propel itself to dwarf planet Ceres. For more information on Dawn's three engines, and a comparison to a familiar ship from science fiction, see the June Dawn Journal.