Archive for the ‘JPL’ Category

Near-Earth Objects: Finding Them Before They Find Us – Yeomans

February 24, 2013

Near-Earth Objects: Finding Them Before They Find Us by Donald K. Yeomans. Here’s a popular-audience space science book that I wasn’t aware of, just published in October 2012 (copyright 2013), with a practical and direct title. ūüôā And as a result of the Chelyabinsk meteor, his book is number one in a specialized subcategory at Amazon: #1 in Books > Professional & Technical > Professional Science > Astronomy & Space Science > Comets, Meteors & Asteroids

Youmans of course is an NASA expert of long-standing repute in these areas, so I’ve just ordered this for myself and in appreciation of his decades of effort to caution the world. Happily, it’s a slim 192 page book with only a U$16.37 impact to the wallet at Amazon. 12 of these pages are one of the best and most thorough indexes I’ve ever seen in terms of including subheadings within an entry.

This is the best of these recommended Earth-impact books for the public, with ten clear and succinct chapters.

Near-Earth Objects: Finding Them Before They Find Us by Donald K. Yeomans.


Dawn Rendezvous With Vesta Rock animation

July 25, 2011

I saved individual frames from Dawn simulator images covering 2 weeks as the spacecraft arrived at Vesta and created a Dawn rendezvous set at Flickr.  Play them as a slideshow! (Let the slideshow run once first to download the images, then it should run faster on replay.  For me, slides display at 3 second intervals, resulting in a two minute animation.  Your flickerage will vary.)
Simulation courtesy of Gregory J. Whiffen, JPL.  I encourage him to do an official time-lapse, once he has time out from frequent Vesta texture map updates.  He has other Dawn viewpoint sims and charts at

This animation is made of frames from this feed:

Dawn spacecraft arrives at Vesta rock’s orbit

July 19, 2011

Here’s the initial image, pic, picture, photo, and photograph of Vesta from orbit.¬† (I’ve noticed all the different search terms people are using for images.¬† Smile.)

Vesta from Dawn spacecraft orbit distance 9,500 kilometers July 17, 2011

Vesta from Dawn spacecraft orbit distance 9,500 kilometers July 17, 2011

Go here to see NASA info:

Previous NASA images are in my earlier post and updates:

After a year of shifting survey and mapping orbits, Dawn will relight its drive and start the 2 year and nine months flight to Ceres.  This will add another 20,000 hours of powered flight to the flightlog of these incredible engines; three are aboard Dawn, taking turns shaping its orbit with the 5-millionths of a earth gravity strength ion-drive thrust.

One month to Vesta rock’s Dawn orbit – 1st spin movie

June 18, 2011
Vesta from Dawn spacecraft July 9th 2011

Vesta from Dawn spacecraft July 9th 2011 41,000 km

NASA’s solar-electric ion-drive Dawn¬†spacecraft is¬†in¬†its final three month¬†approach phase¬†to the second largest Main Belt asteroid, Vesta.

NASA Dawn probe sends first time-lapse rotation movie of Vesta

You can view this 37 second Youtube movie here:

20 navigation images, pictures,¬†or pics¬†are looped 15 times as we see a quarter-rotation of Vesta.¬† The largest crater (or ‘Feature B’ – we aren’t sure yet if it is a crater)¬†is 60 miles across; Vesta’s diameter is 500 kilometers, or 300 miles.

The Dawn homepage has all the information.

Dawn has traveled in interplanetary cruise mode for nearly three and three-quarters years since its launch Sept 27th, 2007; over 2.2 years of that has been powered ion-drive flight, greatly expanding our experience with these efficient engines to beyond 20,000 hours.  Here is the powered-trajectory Timeline, with green sections for when one of the thrusters was on; there are three Xenon-ion thruster engines, that are used one at a time in a rotation schedule that averages out the wear on each engine.


Vesta Dawn powered trajectory chart. Green sections of Dawn trajectory are powered flight segments.



%d bloggers like this: