Ken Kremer — SpaceUpClose.com — 21 August 2018
FL – NASA’s groundbreaking Dawn
spacecraft continues to gather additional spectacular close up imagery of the remarkable
and famous bright spots and craters on dwarf planet Ceres as the mission nears
the conclusion of its amazing 11-year trek.
The bright spots
are mostly composed of sodium carbonate and ammonium chloride that somehow spouted
as slushy brines and leaked their way to the surface forming impressive and
unique salt mounds and spots on the rugged Cerean surface.
The famous and
mysterious brights spots of Occator Crater are a particular focus of Dawn’s last
orbits zeroing in on the Cerealia Facula and Vinalia Faculae fracture features of salt deposits.
The pair of prominent spots looked like a pair
of eyes staring out eerily from Ceres surface from a distance before Dawn achieved
orbit back in 2015.
The imaging team
of Ken Kremer and Marco Di Lorenzo has combined the new individual images of taken by Dawn’s framing camera into a series
of mosaics for Space UpClose – see above and herein.
flying around Ceres in a highly elliptical orbit and enjoying huge success in its
second extended mission – as it captures the highest resolution images ever
taken of the dwarf plant as well as the final series of close up imagery and
spectral data on its elemental and chemical composition with a trio of science
The new imagery reveals
new insights into the origin and evolution of the mysterious alien world – which
is the largest object located in the main Asteroid Belt between Mars and
“The new images of Occator Crater and the surrounding
areas have exceeded expectations, revealing beautiful, alien landscapes,”
said Carol Raymond of JPL, principal
investigator of the Dawn mission.
Occator Crater is an impact crater measuring 57 miles (92
kilometers) across and 2.5 miles (4 kilometers) deep.
appears to be shaped by impacts into its volatile-rich crust, resulting in
intriguing, complex geology, as we can see in the new high-resolution mosaics
of Cerealia Facula and Vinalia Faculae.”
This second extended mission also marks Dawn’s final orbit
and eternal resting place – ranging from a high of about 2,500 miles (4,000 kilometers) and diving down
22 miles (35 kilometers) about once per day.
For context that’s about
three times the altitude of a passenger jet routinely flying on Earth.
The long-lived spacecraft reached this final orbit in early
June and is gathering exquisitely detailed imagery and collecting high
resolution spectral composition measurements involving gamma
ray and neutron spectra, infrared and visible spectra, and gravity data.
Dawn’s observations focus on the area around
Occator and Urvara craters, with “the main goal of understanding the evolution
of Ceres, and testing for possible ongoing geology.”
“NASA’s Dawn spacecraft reached its lowest-ever and final
orbit around dwarf planet Ceres on June 6 and has been returning thousands of
stunning images and other data,” NASA said in a statement.
“Besides the high-resolution images, the spacecraft is
collecting gamma ray and neutron spectra, infrared and visible spectra, and
gravity data. The observations focus on the area around Occator and Urvara
craters, with the main goal of understanding the evolution of Ceres, and
testing for possible ongoing geology.”
The fuel supply of hydrazine is very low and could run out
anytime over the next few months – between now and October.
Engineers can’t say precisely how long since there is no
fuel gauge in the storage to measure what remains. Its all based on mission
long calculations of fuel expenditures – which is an imprecise art.
“Within a few months, Dawn is expected to run out of a key
fuel, hydrazine, which feeds thrusters that control its orientation and keeps
it communicating with Earth. When that happens, sometime between August and
October, the spacecraft will stop operating, but it will remain in orbit around
dwarf planet Ceres,” according to NASA.
It reached orbit
around Ceres in 2015 and has gathered hundreds of thousands of images and
measurements ever since.
“At Ceres, the spacecraft discovered brilliant, salty
deposits decorating the dwarf planet like a smattering of diamonds. The science
behind these bright spots is even more compelling: they are mainly sodium carbonate and ammonium chloride that somehow
made their way to the surface in a slushy brine from within or below the
The new data will help scientists piece
together the relationships between bright and dark materials on the floor of
Occator Crater. It exhibits impact processes, landslides and cryovolcanism the source
of the bright spots.
“Observations, modeling and laboratory
studies helped us conclude that the bright spots are either formed by impacts
interacting with the crust, or that a reservoir of briny melt contributed to
their formation,” said JPL Dawn scientist Jennifer Scully, in a statement
concerning data presented at recent the Committee on SPAce Research (COSPAR) July
2018 meeting in Pasadena.
Dawn is the first
spacecraft to orbit two worlds – 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.
“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.”
Dawn was built by Orbital ATK, now Northrup Grumman and
launched on a ULA Delta II rocket from Florida. It swung by Mars before arriving
at its first target, Vesta, the second most massive object in the asteroid
Watch for Ken’s continuing onsite coverage of NASA, SpaceX, ULA,
Boeing, Lockheed Martin, Orbital ATK 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