DC Agle Jet Propulsion Laboratory, Pasadena, Calif.
A relatively large near-Earth asteroid discovered nearly three years ago will fly safely past Earth on April 19 at a distance of about 1.1 million miles (1.8 million kilometers), or about 4.6 times the distance from Earth to the moon. Although there is no possibility for the asteroid to collide with our planet, this will be a very close approach for an asteroid of this size.
The asteroid, known as 2014 JO25, was discovered in May 2014 by astronomers at the Catalina Sky Survey near Tucson, Arizona — a project of NASA’s NEO Observations Program in collaboration with the University of Arizona. (An NEO is a near-Earth object). Contemporary measurements by NASA’s NEOWISE mission indicate that the asteroid is roughly 2,000 feet (650 meters) in size, and that its surface is about twice as reflective as that of the moon. At this time very little else is known about the object’s physical properties, even though its trajectory is well known.
Written by Whitney Clavin Jet Propulsion Laboratory, Pasadena, California January 30, 2017
A new device on the W.M. Keck Observatory in Hawaii has delivered its first images, showing a ring of planet-forming dust around a star, and separately, a cool, star-like body, called a brown dwarf, lying near its companion star.
The device, called a vortex coronagraph, was recently installed inside NIRC2 (Near Infrared Camera 2), the workhorse infrared imaging camera at Keck. It has the potential to image planetary systems and brown dwarfs closer to their host stars than any other instrument in the world.
Written by Tara Roberts University of Idaho Communications
For NASA Jet Propulsion Laboratory, Pasadena, California
October 21, 2016 at 1:04 p.m. EDT
NASA’s Voyager 2 spacecraft flew by Uranus 30 years ago, but researchers are still making discoveries from the data it gathered then. A new study led by University of Idaho researchers suggests there could be two tiny, previously undiscovered moonlets orbiting near two of the planet’s rings.
Rob Chancia, a University of Idaho doctoral student, spotted key patterns in the rings while examining decades-old images of Uranus’ icy rings taken by Voyager 2 in 1986. He noticed the amount of ring material on the edge of the alpha ring — one of the brightest of Uranus’ multiple rings — varied periodically. A similar, even more promising pattern occurred in the same part of the neighboring beta ring.
“When you look at this pattern in different places around the ring, the wavelength is different — that points to something changing as you go around the ring. There’s something breaking the symmetry,” said Matt Hedman, an assistant professor of physics at the University of Idaho, who worked with Chancia to investigate the finding.
While some technologies were created to make spacecraft move billions of miles, the Disturbance Reduction System has the opposite goal: To keep a spacecraft as still as possible.
The thruster system, managed by NASA’s Jet Propulsion Laboratory, Pasadena, California, is part of the European Space Agency’s LISA Pathfinder spacecraft, which launched from Kourou, French Guiana on Dec. 3, 2015 GMT (Dec. 2 PST). LISA Pathfinder will test technologies that could one day allow detection of gravitational waves, whose effects are so miniscule that a spacecraft would need to remain extremely steady to detect them. Observing gravitational waves would be a huge step forward in our understanding of the evolution of the universe.
Now, LISA Pathfinder is on its way to Lagrange Point L1, about 930,000 miles (1.5 million kilometers) from Earth in the direction of the sun. L1 is a special point that a spacecraft can orbit while maintaining a nearly constant distance to Earth. This month, scientists and engineers have been switching on LISA Pathfinder’s instruments to test them in space. This has included the Disturbance Reduction System instrument computer and thrusters.
The system uses colloid micronewton thrusters, which operate by applying an electric charge to small droplets of liquid and accelerating them through an electric field, to precisely control the position of the spacecraft. Thrusters that work this way had never been successfully operated in space before LISA Pathfinder launched.
As of Jan. 10, all eight identical thrusters, developed by Busek Co., Natick, Massachusetts, with technical support from JPL, passed their functional tests. The thrusters achieved their maximum thrust of 30 micronewtons, equivalent to the weight of a mosquito. This level of precision is necessary to counteract small forces on the spacecraft such as the pressure of sunlight, with the result that the spacecraft and the instruments inside are in near-perfect free-fall. A mission to detect gravitational waves would need that level of stability.
“We reached a major milestone with this technology development,” said Phil Barela, Disturbance Reduction System project manager at JPL. “The DRS is helping point the way to a system that could be used to detect gravitational waves in the future.”
Gravitational waves are one of the last unverified predictions from the theory of General Relativity, which Albert Einstein published about a century ago. Einstein wrote that as massive bodies accelerate, such as black holes, they produce distortions in space-time. Scientists are interested in observing and characterizing these ripples in space-time so that they can learn more about the astrophysical systems that produce them, and about gravity itself. Proposed experiments to detect them from space, such as a future LISA mission, would need to measure how two freely-falling objects move ever so slightly, relative to each other, as a result of gravitational waves. In order to rule out any disturbances that could mask these waves, there must be a system to compensate for solar pressure and other factors. The Disturbance Reduction System on LISA Pathfinder will demonstrate this technology.
The Disturbance Reduction System could also lead to advanced thruster systems for other space applications. Space telescopes need to be very stable to detect distant planets in other solar systems, for example, and could use a similar system. A set of thrusters like the Disturbance Reduction System’s could also be used in small satellites to help synchronize flying patterns.
LISA Pathfinder will reach its final orbit on Jan. 22, and begin science operations on March 1. For the first phase of the mission’s science operations, a thruster technology system designed by the European Space Agency will be used. JPL’s Disturbance Reduction System will then take over in June or July, operating for 90 days.
LISA Pathfinder is managed by the European Space Agency. The spacecraft was built by Airbus Defence and Space, Ltd., United Kingdom. Airbus Defence and Space, GmbH, Germany, is the payload architect for the LISA Technology Package. The DRS is managed by JPL. The California Institute of Technology manages JPL for NASA.