Dawn Goes Dark with Fuel Exhausted, Ending NASA’s 1st Mission to 2 Largest Asteroid Belt Worlds

Artist's rendering shows NASA's Dawn spacecraft maneuvering above Ceres with its ion propulsion system.  Credits: NASA/JPL-Caltech

Ken Kremer -- SpaceUpClose.com & RocketSTEM - - 6 November 2018

CAPE CANAVERAL, FL –  NASA’s groundbreaking Dawn spacecraft has gone dark after exhausting all its maneuvering fuel – thus ending an 11-year mission to the two largest worlds in the main Asteroid Belt that are fossilized remnants from the dawn of our Solar System.

Dawn is the first spacecraft to orbit two worlds – Ceres & Vesta – enabled only by its unique ion propulsion thruster system which is vastly more powerful than chemical thrusters. 

The spacecraft first studied Vesta for 14 months, the second most massive asteroid in 2011 and 2012. Then it broke out of orbit and set off for Ceres.

"Dawn's unique mission to orbit and explore two strange new worlds would have been impossible without ion propulsion," said Marc Rayman of NASA's Jet Propulsion Laboratory, Pasadena, California, who has served as Dawn's mission director, chief engineer and project manager. 

"Dawn is truly an interplanetary spaceship, and it has been outstandingly productive as it introduced these fascinating and mysterious worlds to Earth."

High resolution mosaic of the side by side Cerealia Facula (left) and Vinalia Faculae (right) features shows the famous bright spots of salt deposits inside Occator Crater on Ceres. It is based on images obtained by NASA's Dawn spacecraft in its second extended mission, from an altitude as low as about 21 miles (34 kilometers) since June 2018. This stitched mosaic reveals the intricate pattern between bright and dark material across these flow features, which scientists will use to infer the history of this area, in particular the role of the fractures in the exposure of bright salts onto the surface.  Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/Ken Kremer/kenkremer.com/Marco Di Lorenzo

Dawn was built by Orbital ATK, now Northrup Grumman and launched on a ULA Delta II rocket from Florida on 27 September 2007 – which I witnessed from Jetty Park Pier, Port Canaveral, FL.

It swung by Mars before arriving at its first target, Vesta, the second most massive object in the asteroid belt. 

This context collage shows the location of a prominent mound of the famous bright spots of salt deposits located on the western side of Cerealia Facula (upper & lower right) and Vinalia Faculae (lower left) and inside Occator crater (upper left) on dwarf planet Ceres. Newly obtained highest ever resolution images were taken of the bright salt deposits inside Occator by NASA's Dawn spacecraft since June 2018 from a record low altitude of about 21 miles (34 kilometers) above Ceres, colorized mosaics.  Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/Ken Kremer/kenkremer.com/Marco Di Lorenzo

Here is the NASA Press Release – until my story is ready:

NASA’s Dawn spacecraft has gone silent, ending a historic mission that studied time capsules from the solar system’s earliest chapter.

Dawn missed scheduled communications sessions with NASA's Deep Space Network on Wednesday, Oct. 31, and Thursday, Nov. 1. After the flight team eliminated other possible causes for the missed communications, mission managers concluded that the spacecraft finally ran out of hydrazine, the fuel that enables the spacecraft to control its pointing. Dawn can no longer keep its antennas trained on Earth to communicate with mission control or turn its solar panels to the Sun to recharge.

Video Caption: NASA’s Dawn spacecraft turned science fiction into science fact by using ion propulsion to explore the two largest bodies in the main asteroid belt, Vesta and Ceres. The mission ended on. Nov. 1, 2018, when the spacecraft ran out of hydrazine, which keeps it oriented and in communication with Earth.  Credits: NASA/JPL-Caltech

The Dawn spacecraft launched 11 years ago to visit the two largest objects in the main asteroid belt. Currently, it’s in orbit around the dwarf planet Ceres, where it will remain for decades.

“Today, we celebrate the end of our Dawn mission – its incredible technical achievements, the vital science it gave us, and the entire team who enabled the spacecraft to make these discoveries,” said Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate in Washington. “The astounding images and data that Dawn collected from Vesta and Ceres are critical to understanding the history and evolution of our solar system.”

This photo of Ceres and the bright regions of Occator Crater was one of the last views NASA's Dawn spacecraft transmitted before it completed its mission. This view, which faces south, was captured on Sept. 1, 2018, at an altitude of 2,340 miles (3,370 kilometers) as the spacecraft was ascending in its elliptical orbit.  Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Dawn launched in 2007 on a journey that put about 4.3 billion miles (6.9 billion kilometers) on its odometer. Propelled by ion engines, the spacecraft achieved many firsts along the way. In 2011, when Dawn arrived at Vesta, the second largest world in the main asteroid belt, the spacecraft became the first to orbit a body in the region between Mars and Jupiter. In 2015, when Dawn went into orbit around Ceres, a dwarf planet that is also the largest world in the asteroid belt, the mission became the first to visit a dwarf planet and go into orbit around two destinations beyond Earth.

"The fact that my car's license plate frame proclaims, 'My other vehicle is in the main asteroid belt,' shows how much pride I take in Dawn," said Mission Director and Chief Engineer Marc Rayman at NASA's Jet Propulsion Laboratory (JPL). "The demands we put on Dawn were tremendous, but it met the challenge every time. It's hard to say goodbye to this amazing spaceship, but it’s time."

This photo of Ceres and one of its key landmarks, Ahuna Mons, was one of the last views Dawn transmitted before it completed its mission. This view, which faces south, was captured on Sept. 1, 2018, at an altitude of 2220 miles (3570 kilometers) as the spacecraft was ascending in its elliptical orbit.  Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

The data Dawn beamed back to Earth from its four science experiments enabled scientists to compare two planet-like worlds that evolved very differently. Among its accomplishments, Dawn showed how important location was to the way objects in the early solar system formed and evolved. Dawn also reinforced the idea that dwarf planets could have hosted oceans over a significant part of their history – and potentially still do.

“In many ways, Dawn’s legacy i­s just beginning,” said Princ­­ipal Investigator Carol Raymond at JPL. “Dawn’s data sets will be deeply mined by scientists working on how planets grow and differentiate, and when and where life could have formed in our solar system. Ceres and Vesta are important to the study of distant planetary systems, too, as they provide a glimpse of the conditions that may exist around young stars.”

Because Ceres has conditions of interest to scientists who study chemistry that leads to the development of life, NASA follows strict planetary protection protocols for the disposal of the Dawn spacecraft. Dawn will remain in orbit for at least 20 years, and engineers have more than 99 percent confidence the orbit will last for at least 50 years.

So, while the mission plan doesn't provide the closure of a final, fiery plunge – the way NASA’s Cassini spacecraft ended last year, for example – at least this is certain: Dawn spent every last drop of hydrazine making science observations of Ceres and radioing them back so we could learn more about the solar system we call home.

The Dawn mission is managed by JPL for NASA's Science Mission Directorate in Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Alabama. JPL is responsible for overall Dawn mission science. Northrop Grumman in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team.

NASA’s Dawn Asteroid orbiter launches on United Launch Alliance Delta II Heavy rocket on September 27, 2007 from Launch Complex-17 on Cape Canaveral Air Force Station, FL. Credit: Ken Kremer/kenkremer.com/spaceupclose.com

Watch for Ken’s continuing onsite coverage of NASA, SpaceX, ULA, Boeing, Lockheed Martin, Northrop Grumman and more space and mission reports direct from the Kennedy Space Center, Cape Canaveral Air Force Station, Florida and Wallops Flight Facility, Virginia.

Stay tuned here for Ken's continuing Earth and Planetary science and human spaceflight news: www.kenkremer.com –www.spaceupclose.com – twitter @ken_kremer – email: ken at kenkremer.com

Dr. Kremer is a research scientist and journalist based in the KSC area.

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