THE IION THRUSTER

FROM: U.S. DEPARTMENT OF DEFENSE

by jtozer

Saturday Space Sight: Ion Thruster Sets World Record

While the Dawn spacecraftis visiting the asteroids Vesta and Ceres, NASA Glenn has been developing the next generation of ion thrusters for future missions. NASA's Evolutionar Xeon Thruster (NEXT) Project has developed a 7-kilowatt ion thruster that can provide the capabilities needed in the future.

An ion thruster produces small levels of thrust relative to chemical thrusters, but does so at higher specific impulse (or higher exhaust velocities), which means that an ion thruster has a fuel efficiency of 10-12 times greater than a chemical thruster.

The higher the rocket’s specific impulse (fuel efficiency), the farther the spacecraft can go with a given amount of fuel.

Given that an ion thruster produces small levels of thrust relative to chemical thrusters, it needs to operate in excess of 10,000 hours to slowly accelerate the spacecraft to speeds necessary to reach the asteroid belt or beyond.

The NEXT ion thruster has been operated for over 43,000 hours, which for rocket scientists means that the thruster has processed over 770 kilograms of xenon propellant and can provide 30 million-newton-seconds of total impulse to the spacecraft. This demonstrated performance permits future science spacecraft to travel to varied destinations, such as extended tours of multi-asteroids, comets, and outer planets and their moons.

Photo Credit:  NASA

NUSTAR, GALACTIC EXPLORER

FROM:  U.S. DEFENSE DEPARTMENT ARMED WITH SCIENCE
This photo shows the Orbital Sciences Corporation Pegasus XL rocket with the NuSTAR spacecraft after attachment to the L-1011 carrier aircraft known as "Stargazer." Image credit: NASA/Randy Beaudoin, VAFB 

Written on JUNE 10, 2012 AT 7:54 AM by JTOZER
NuStar Headed To The Stars
 NASA‘s Nuclear Spectroscopic Teelscope Array, or NuSTAR, is now perched atop its Pegasus XL rocket, strapped to the plane that will carry the mission to an airborne launch. Launch is scheduled for June 13, no earlier than 8:30 a.m. PDT (11:30 a.m. EDT).
The plane — the L-1011 “Stargazer” aircraft — is now at Vandenberg Air Force Base  in central California. It is scheduled to fly to Kwajalein Atoll in the central Pacific Ocean from June 5 to 6. About an hour before launch, the plane will lift off from the island, and drop NuSTAR and its rocket over the ocean. The rocket will then ignite, carrying NuSTAR to its final orbit around Earth’s equator.

NuSTAR will be the first space telescope to create sharp images of X-rays with high energies, similar to those used by doctors and dentists. It will conduct a census for black holes, map radioactive material in young supernovae remnants, and study the origins of cosmic rays and extreme physics around collapsed stars.

NuSTAR is a Small Explorer mission led by the California Institute of Technology in Pasadena and managed by NASA’s Jet Propulsion Laboratory, also in Pasadena, for NASA’s Science Mission Directorate in Washington. The spacecraft was built by Orbital Sciences Corporation, Dulles, Va.  Launch management and government oversight for the mission is the responsibility of NASA’s Launch Services Program at the Kennedy Space Center in Florida.

HUBBLE OBSERVES GALAXY 4980

FROM:  U.S. DEPARTMENT OF DEFENSE ARMED WITH SCIENCE
Written on MAY 27, 2012 AT 7:10 AM by JTOZER
A Spiral Galaxy in Hydra
This image from the NASA Hubble Space Telescope shows NGC 4980, a spiral galaxy in the southern constellation of Hydra. The shape of NGC 4980 appears slightly deformed, something which is often a sign of recent tidal interactions with another galaxy. In this galaxy’s case, however, this appears not to be the case as there are no other galaxies in its immediate vicinity.

The image was produced as part of a research program into the nature of galactic bulges, the bright, dense, elliptical centers of galaxies. Classical bulges are relatively disordered, with stars orbiting the galactic center in all directions. In contrast, in galaxies with so-called pseudobulges, or disc-type bulges, the movement of the spiral arms is preserved right to the center of the galaxy.

Although the spiral structure is relatively subtle in this image, scientists have shown that NGC 4980 has a disc-type bulge, and its rotating spiral structure extends to the very center of the galaxy.

A galaxies’ bright arms are the location of new star formation in spiral galaxies, and NGC 4980 is no exception. The galaxy’s arms are traced out by blue pockets of extremely hot newborn stars are visible across much of its disc. This sets it apart from the reddish galaxies visible in the background, which are distant elliptical galaxies made up of much older, and hence redder, stars.

This image is composed of exposures taken in visible and infrared light by Hubble’s Advanced Camera for Surveys. The image is approximately 3.3 by 1.5 arcminutes in size.