Published : Wednesday, January 31, 2018 | 5:35 PM
NASA’s Dawn spacecraft, launched in 2007 and now orbiting Ceres for the third year, is revealing many startling findings about the dwarf planet that also happens to be the largest object in the asteroid belt lying between between the orbits of Mars and Jupiter.
Speaking to Forbes magazine, Dr. Marc Rayman, Dawn’s Mission Director and Chief Engineer based at the Jet Propulsion Laboratory in Pasadena, said Ceres is “a faint smidge of light amidst the stars,” and not much was known about it.
Today, over the last 1,000 days it has in orbit, Dawn has allowed JPL and NASA scientists to learn more than anything known from the previous 217 years — since Ceres was discovered in 1801.
Scientists at JPL and other NASA agencies have taken over 55,000 photographs of Ceres and have been able to map the dwarf planet’s surface, with its interesting bright spots, a large ice inventory, as well as an ancient cryovolcano with a magma of water, salt and rock, Forbes magazine says.
Rayman describes Ceres in the interview as “an exotic alien landscape.”
“Dawn has provided us with a richly-detailed portrait of a unique world,” he tells the magazine.
When the astronomer Giuseppe Piazzi first spotted Ceres, he called it a comet. Later astronomers called it a planet, as it revolves around the sun, and then an asteroid. In 2006, a year before Dawn launched into space, scientists reclassified Ceres as a dwarf planet – almost 600 miles across, about the size of Texas.
Dawn took about seven and a half years to reach Ceres’ orbit, and that included a 14-month side trip to Vesta, the brightest and biggest asteroid in the sky.
Rayman said his team took about 31,000 pictures of Vesta as Dawn passed the asteroid. As the spacecraft approached Ceres, the team started seeing the bright spots on the dwarf planet, specifically within the 57-mile wide Occator Crater.
Raymand told Forbes these are salt flats, left after water molecules dissipated. He said a vast amount of salt water is under the surface of Ceres, which possibly also holds some pockets of liquid water.
Around Ceres’ Ernutet Crater, Rayman’s team found their biggest surprise – organic materials, the building blocks of life. Rayman, though, is skeptical that life exists on Ceres.
“It’s possible, but highly unlikely,” he tells Forbes.
In his blog on the JPL website, Rayman tells of the future of Dawn’s mission at Ceres.
“We can look forward to some remarkable pictures. Some will be sharper than the best so far, but not by as much as you might expect. When it is in the low altitude segment of its orbit, Dawn will be moving faster than ever at Ceres,” Rayman writes. “If you were in a plane traveling hundreds of miles per hour, it would not be hard to take a picture of the ground six miles beneath you. But if you were in a car driving at that speed or even faster, despite being closer to the ground, your pictures might not be better. The situation on Dawn isn’t that severe, so the photography certainly will improve somewhat on what we already have.”
Dawn continues on an orbit around Ceres that ranges from a little more than 3,000 miles to nearly 24,000 miles. It takes 30 days to complete one revolution. The spacecraft will continue operating in this elliptical orbit at least until April, the earliest opportunity to start its descent.
“With the help of a team of dedicated controllers, Dawn has shown itself to be a fantastically capable and resourceful explorer,” Rayman said. “Many new questions have to be answered and many challenges overcome for it to undertake another (and final) year in its bold expedition. But we can be hopeful that the creativity, ingenuity, and passion for knowledge and adventure that have propelled Dawn so very far already will soon allow it to add rich new details to what is already a celestial masterpiece.”
JPL manages the Dawn mission 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. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., 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.
For a complete list of mission participants, visit www.dawn.jpl.nasa.gov/mission.