Tag Archives: flyby

Chinese scientists have concluded that the asteroid Toutatis is a rubble pile barely held together by gravity, based on data obtained from Chang’e 2’s flyby one year ago.

Chinese scientists have concluded that the asteroid Toutatis is a rubble pile barely held together by gravity, based on data obtained from Chang’e 2’s flyby one year ago.

Comet ISON makes its close flyby of the sun today.

Comet ISON makes its close flyby of the sun today.

Three possible fates await Comet ISON, according to Don Yeomans, manager of NASA’s Near-Earth Object Program Office at the agency’s Jet Propulsion Laboratory in Pasadena, Calif.

“It could be tough enough to survive the passage of the sun and be a fairly bright naked-eye object in the early morning sky in the first week of December,” Yeomans said in a statement. “Or, the sun could actually pull it apart. The tidal forces could actually pull this comet apart and so it becomes several chunks rounding the sun and putting on a great show again in early December. Or, if the comet is very weak, it could break up into a cloud of dust and be a complete bust in December.”

So far the comet has been a big disappointment in terms of brightness. However, its flyby today will be interesting as scientists will get a chance to observe one of the largest sun-grazers they’ve ever seen do this.

Engineers hope Juno’s Earth flyby yesterday will help solve a mystery seen in previous flybys by unmanned probes.

The uncertainty of science: Engineers hope Juno’s Earth flyby yesterday will help solve a mystery seen in previous flybys by unmanned probes.

Since 1990, mission controllers at ESA and NASA have noticed that their spacecraft sometimes experience a strange variation in the amount of orbital energy they pick up from Earth during flybys, a technique routinely used to fling satellites deep into our Solar System. The unexplained variation is noticed as a tiny difference in the expected speed gained (or lost) during the passage.

The variations are extremely small: NASA’s Jupiter probe ended up just 3.9 mm/s faster than expected when it swung past Earth in December 1990. The largest variation– a boost of 13.0 mm/s – was seen with NASA’s NEAR asteroid craft in January 1998. Conversely, the differences during swingbys of NASA’s Cassini in 1999 and Messenger in 2005 were so small that they could not be confirmed.

The experts are stumped.

It is likely that these small variations are related in some way with simple engineering and not some unknown feature of gravity. Nonetheless, it remains a mystery.

After the unmanned probe Juno zipped past the Earth on its way to Jupiter today, it unexpectedly went into safe mode.

After the unmanned probe Juno zipped past the Earth on its way to Jupiter today, it unexpectedly went into safe mode.

Engineers continued to diagnose the issue, which occurred after Juno whipped around Earth in a momentum-gathering flyby. Up until Wednesday, Juno had been in excellent health. While in safe mode, it can communicate with ground controllers, but its activities are limited.

It is unclear at the moment why this happened.

More info on the asteroid “flyby” of Earth this coming November 8

More information on the asteroid “flyby” of Earth this coming November 8.

“On November 8, asteroid 2005 YU55 will fly past Earth and at its closest approach point will be about 325,000 kilometers [201,700 miles] away,” said Don Yeomans, manager of NASA’s Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. “This asteroid is about 400 meters [1,300 feet] wide – the largest space rock we have identified that will come this close until 2028.”