Articles

Emily Lakdawalla

Water ice at Mercury's poles? That's crazy, right? Mercury is so close to the Sun that it seems inconceivable that you could have water ice there. But Mercury's rotational axis has virtually no tilt (MESSENGER has measured its tilt to be less than 1 degree), so there are areas at Mercury's poles, most often (but not always) within polar craters, where the Sun never rises above the horizon to heat the surface.

Emily Lakdawalla

JAXA's solar sail mission IKAROS is still hibernating, and there's no way of knowing if the spacecraft will reawaken or not. They try to raise contact with the spacecraft once a month, with the last attempt being made on March 10; we can only wait to see if they'll succeed. What better time to release a theme song for the mission? IKAROS has always been even more full of personality even than other JAXA missions (which is saying a lot).

Emily Lakdawalla

Just a quick note because I didn't want to let the weekend go by without telling people that Venus Express' star trackers are back online.

Emily Lakdawalla

Two brief mission updates. First, the good news: NASA announced yesterday that the twin GRAIL spacecraft have begun the science phase of the mission, transmitting precisely timed signals to each other in order to map the Moon's gravity field. The bad news: according to ESA, since the recent solar storm passed Venus, both of Venus Express' star trackers are suddenly unable to detect stars.

Emily Lakdawalla

ESA announced this morning that the launch of their BepiColombo mission, a cooperative effort with JAXA, has been delayed from its originally planned July 2014 to the backup launch window in August 2015.

Emily Lakdawalla

Japan's Venus climate orbiter Akatsuki failed to enter orbit in December 2010 when a clogged valve caused catastrophic damage to its main engine. Since then, JAXA's engineers and navigators have determined that although the main engine is a total loss, there is the possibility of achieving Venus orbit on a future encounter, using only the attitude control rockets.

Emily Lakdawalla

JAXA's solar sail demonstration craft IKAROS is still puttering along, 17 months after it launched, and its controllers back on Earth keep coming up with new things to try with it. I'm pretty amazed by the most recent trick: reversing its spin direction. This may not sound like a big deal, but it is, especially for IKAROS.

Emily Lakdawalla

Today I largely spent in the MESSENGER sessions. They have a lot of data to talk about.

Emily Lakdawalla

JAXA held a press conference on June 30 about the latest report from the review board that is charged with finding out what exactly caused Akatsuki's failure to enter orbit at Venus, and what that implies for the possibility of Akatsuki to try again when it returns to Venus in 2015 or 2016.

Emily Lakdawalla

There was a press briefing today giving some early science results from MESSENGER and it was surprisingly meaty. I'm going to focus on just one set of the results that they presented.

Emily Lakdawalla

When Mariner 10 flew past Mercury, it caught an immense impact basin lying half in and half out of sunlight, which they named Caloris. Even with only half the basin visible, scientists knew it was one of the largest in the solar system. Geologists had to wait more than 25 years to see the rest of Caloris, and when they did it turned out to be even bigger than they had thought. But the fact that Caloris was only half in sunlight was fortuitous in one sense, because it meant that the spot on Mercury that was exactly opposite the area of the Caloris impact was also partially in sunlight. That spot looks weird.

Emily Lakdawalla

Regular readers of this blog will find the content of today's 365 Days of Astronomy Podcast familiar, because it's an update on what the solar system exploration spacecraft are up to, based on my monthly

Emily Lakdawalla

Welcome, everyone, to the Planetary Society Blog for the 191st Carnival of Space! Every week, a different webmaster or blogger hosts the Carnival, showcasing articles written on the topic of space.

Emily Lakdawalla

April 2011 will see MESSENGER begin the science phase of its orbital mission at Mercury, and should, I think, also see the start of Dawn's approach observations of Vesta. At Mars, Opportunity is back on the road again, rolling inexorably toward Endeavour. At Saturn, Cassini will continue its focus on Saturn and Titan science.

Emily Lakdawalla

Today the MESSENGER mission held a press briefing to show off some of the first images and other data that are streaming in from the spacecraft, now that it has entered Mercury orbit.

Emily Lakdawalla

This is MESSENGER's very first photo from Mercury orbit, a wide-angle view that reaches right to Mercury's south pole, exposing a very tiny sliver of territory not previously seen by spacecraft.

Emily Lakdawalla

I saw this posted by @Akatsuki_JAXA (the Akatsuki Venus mission's official Twitter identity) and thought it was cute so I'm sharing it here.

Emily Lakdawalla

Just a brief post to announce that at 01:00 UTC MESSENGER completed a 15-minute burn of its main engines to enter orbit at Mercury!

Emily Lakdawalla

The day is finally here! In only five and a half hours, at 00:45 on March 18 (according to the spacecraft's clock), MESSENGER must ignite its main engine and run though a third of its fuel in only 15 minutes in order to enter its planned orbit around Mercury.

Emily Lakdawalla

Today the MESSENGER team briefed the press on the impending arrival of their spacecraft at Mercury.