Friday, May 31, 2013

Big asteroid swinging by Earth has its own moon

Astronomers getting their first close-up glimpse of a giant asteroid about to whiz by Earth found a surprise bonus rock. A smaller moon asteroid is circling the larger space rock, an unusual but not unheard of space phenomenon.

The larger 1.7 mile-wide rock named Asteroid 1998 QE2 will be the closest to Earth on Friday at 4:59 p.m. EDT. Don’t worry, though. It will still be 3.6 million miles away. NASA scientist Paul Chodas (Ch’OH’duhs) said it’s one of the larger asteroids to swing by Earth and is the size of the space rock that wiped out the dinosaurs.

The smaller rock was discovered Wednesday night by astronomers using radar to look at QE2. The moon asteroid is about 2,000 feet wide. That’s about average for such near-Earth objects.

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Thursday, May 23, 2013

Juno Mission Status

May 22 update: Mission controllers received confirmation from the spacecraft today that its MWR, JEDI and Waves instruments were powered off as planned. The magnetometer experiment remains powered on at low data rates. The planned instrument shutdown was done in preparation for the spacecraft’s upcoming switch to its lower data rate antennas as it begins the next phase of its mission, dubbed “Inner Cruise 3” on May 29.

The solar-powered Juno spacecraft and its saucer-shaped high-gain antenna (or HGA) always point sunward, but while Juno is in the inner solar system, Earth’s position on the sky shifts dramatically. Earth’s movement means that Juno cannot always use its HGA and benefit from its high data rate connection. For this reason, the spacecraft has a suite of antennas that allow communications with Earth from other angles, but at the cost of lower data rates, resulting in a reduction in Juno’s ability to transmit science data during that time. Juno’s science instruments will be powered on again shortly before the Earth flyby, slated for Oct. 9.

May 10 update: The Juno spacecraft is in excellent health and is operating nominally. As of May 10, Juno was approximately 50 million miles (80 million kilometers) from Earth. The one-way radio signal travel time between Earth and Juno is currently about 4.5 minutes. Juno is currently traveling at a velocity of about 16 miles (25 kilometers) per second relative to the sun, and increasing. Velocity relative to Earth is about 4.7 miles (7.6 kilometers) per second. Juno has now traveled 722 million miles (1.2 billion kilometers) since launch.

Other recent spacecraft significant events

Juno’s mission ops team performed a flush of the spacecraft’s main engine on May 1, firing the engine for a couple of seconds. The team does this maintenance activity about once per year to flush contaminants from the propellant lines that feed the main engine.

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Thursday, May 2, 2013

NASA’s Planet-Hunting Kepler Spacecraft Faces Serious Health Problems

Health issues are jeopardizing the planet-hunting work of NASA’s prolific Kepler space telescope, which has identified more than 2,700 potential alien worlds to date.

One of Kepler’s reaction wheels — devices that maintain the observatory’s position in space — remains balky despite mitigation attempts. The mission team now regards the problem as unsolvable and is considering what the telescope can do after the wheel fails.

“While the wheel may still continue to operate for some time yet, the engineering team has now turned its attention to the development of contingency actions should the wheel fail sooner, rather than later,” Kepler mission manager Roger Hunter, of NASA’s Ames Research Center in Moffett Field, Calif., wrote in an update Monday (April 29).

The $600 million Kepler observatory detects exoplanets by flagging the tiny brightness dips caused when they pass in front of their host stars from the instrument’s perspective. Kepler’s main goal is to determine how common Earth-like alien planets are throughout the Milky Way galaxy.

The spacecraft needs three functioning reaction wheels to stay locked onto its 150,000-odd target stars. Kepler had four wheels when it launched in March 2009 — three for immediate use, and one spare. But one wheel (known as number two) failed in July 2012, giving Kepler no margin for error.

The currently glitchy wheel (known as number four) has acted up before, but its problems now seem more serious, mission officials said.

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Wednesday, May 1, 2013

Mars Rover Opportunity Slips Into Standby Mode, NASA Says

NASA’s long-lived Opportunity Mars rover has gone into a self-imposed standby mode on the Red Planet, the robot’s handlers say.

Mission controllers for Opportunity, which landed on Mars in January 2004, first learned of the issue on Saturday (April 27). On that day, the rover got back in touch after a nearly three-week communication moratorium caused by an unfavorable planetary alignment called a Mars solar conjunction, in which Mars and Earth are on opposite sides of the sun.

The Opportunity rover apparently put itself into standby on April 22 after sensing a problem during a routine camera check, mission managers said.

“Our current suspicion is that Opportunity rebooted its flight software, possibly while the cameras on the mast were imaging the sun,” Opportunity project manager John Callas, of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., explained in a statement Monday (April 29).

“We found the rover in a standby state called automode, in which it maintains power balance and communication schedules, but waits for instructions from the ground,” Callas added. “We crafted our solar conjunction plan to be resilient to this kind of rover reset, if it were to occur.”

Opportunity’s handlers prepared new commands Monday designed to spur the rover into resuming operations, mission team members said.

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