Hayabusa-2 22 miles from Ryugu
Hayabusa-2 has moved to within 23 miles of the asteroid Ryugu and is expected to reach its planned 12 mile rendezvous distance on June 27.
No new pictures, though I wouldn’t be surprised if some showed up today or tomorrow.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon. from any other book seller, or direct from my ebook publisher, ebookit.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Hayabusa-2 has moved to within 23 miles of the asteroid Ryugu and is expected to reach its planned 12 mile rendezvous distance on June 27.
No new pictures, though I wouldn’t be surprised if some showed up today or tomorrow.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon. from any other book seller, or direct from my ebook publisher, ebookit. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Is it just me, or is anyone else amazed that we can place something so accurately (from this distance) that it’s in orbit TWELVE MILES (!) from the surface of another celestial body?
Col Beausabre asked: “Is it just me, or is anyone else amazed that we can place something so accurately (from this distance) that it’s in orbit TWELVE MILES (!) from the surface of another celestial body?”
Well, they make midcourse corrections, so I lost my amazement decades ago.
On the other hand, some of the mathematics is simple (elliptical orbits) and some is complex (three dimensional differential equations for rendezvous). Plus the spacecraft has to perform correctly after years of aging electronics, radiation bombardment, whatever the limit is for the batteries, and other surprises that come up (Mars Observer failed during a routine midcourse correction on the way to Mars).
Then there are communication time delays, the unknowns of the destination asteroid (is there debris in the neighborhood?), and changes of plan during arrival because something interesting came up. Changes in the plan are risky, as preset commands may be missed during the changes (SOHO was nearly lost because a previously turned off reaction wheel — changed plan — was not taken into account during a routine maneuver).
Come to think of it, there are quite a few failures that happen, so it is amazing that we have as many successes as we do.
Here is a video that helps explain how spacecraft navigate in space:
https://www.youtube.com/watch?v=YAnxt1YPWbk (17 minutes)
Col Beausabre: I am certainly amazed, even if it has happened several times already. One of the amazing things is how they even communicate with the spacecraft. How does it know where it is, after all, there is no GPS out there. See
hub.jhu.edu/2015/07/17/new-horizons-data-transmission/
for a writeup on telecommunications at the distance of Pluto.
I miss TESS. It’s supposed to make its perigee end of June right now soon (it’s so quite about it and NASA mission website doesn’t advertise when the first perigee and thus data download will happen). I don’t know how many exoplanet detections it is expected to have gathered on its first run, but in two years it will have found tens of times more exoplanets than are known to date. I’m surprised by the silence before the storm.
@lodaya
A press conference with scientists on the Cassini team said that they now know the location of Saturn’s center of gravity to within one mile (it is 1½ million miles away). Some press in the audience asked what that’s good for. “-Astronomers make it their job to know where things are!” Ephemera as they call it since thousands of years.
Buzz Aldrin took a PhD in astronautics, on the topic of manual visual star navigation. Just as at sea, it is necessary to know where one is and many methods have been developed to do it.