ESA’s GOCE satellite is on its way back to Earth. Where and when is somewhat speculative however it was said to be “pretty much in the orbital position it was predicted to be”. There are parts of the satellite that are expected to survive re-entry it will be interesting to see how much lead time there ends up being.
The ESA Rocket Science Blog this morning is putting GOCE at about 160 km and it is showing a significant temperature increase in areas of the spacecraft indicating it is interfacing with an increasingly dense atmosphere.
GOCE is expected to fall by another 13 km today with final re-entry in less than two days.
UPDATE: The Sunday Morning Update from ESA has GOCE at about 147 km and dropping 1 km/hr and increasing. The atmospheric drag level is high and increasing.
The end is close.
RE-ENTRY PREDICTION: Predicted Reentry Time: 10 NOV 2013 23:33 UTC ± 4 hours
RE-ENTRY PREDICTION (by ESA Space Debris Coordination Committee): between 18:30 UTC – 24:00 UTC, Sunday, 10 November (19:30 CET – 01:00 CET, Sunday to Monday, 10/11 November); the most probable impact ground swath largely runs over ocean and polar regions.
Hubble looks at a six-tailed asteroid. Credit: NASA, ESA, D. Jewitt (University of California, Los Angeles), J. Agarwal (Max Planck Institute for Solar System Research), H. Weaver (Johns Hopkins University Applied Physics Laboratory), M. Mutchler (STScI), and S. Larson (University of Arizona)
How cool is this? It’s an asteroid with an identity crisis. Just like the press release (linked below) says, an asteroid normally appears as a point of light. Not P/2013 P5, this thing is very comet-like in that it has a tail. In fact it has six tails!?
Six Tails? Wait, comets are ice and asteroids are rock. How does that happen?
Careful modeling by team member Jessica Agarwal of the Max Planck Institute for Solar System Research in Lindau, Germany, showed that the tails could have been formed by a series of impulsive dust-ejection events. She calculated that the first ejection event occurred on April 15 and the last one on Sept. 4. The rest sequentially erupted on July 18, July 24, Aug. 8, and Aug. 26. Radiation pressure from the Sun smears out the dust into streamers.
The asteroid could possibly have been spun up if the pressure of sunlight exerted a torque on the body. If the asteroid’s spin rate became fast enough, Jewitt said, the asteroid’s weak gravity would no longer be able to hold it together. Dust might avalanche downslope towards the equator, and maybe shatter and fall off, eventually drifting into space to make a tail. So far, only a small fraction of the main mass, perhaps 100 to 1,000 tons of dust, has been lost. The 700-foot-radius nucleus is thousands of times more massive.
Follow-on observations may show if the dust leaves the asteroid in the equatorial plane, and this would be pretty strong evidence for a rotational breakup. Astronomers will also try to measure the asteroid’s true spin rate.
Here’s the full press release and links to larger images.
Moon shadow on Earth during Sunday’s eclipse. Credit: Aerospace Corporation
Just look at that! During the Solar Eclipse last Sunday (03 Nov) the cubesat known as AeroCube-4 took this image of the moon’s shadow on Earth.
I was immediately struck by the great example of the umbral (darkest) and penumbral (shaded around the darkest area) areas. Excellent.
According to the Aerospace Corporation:
AeroCube-4 was west of the moon shadow, flying in a northeasterly direction. The view in the photo is toward the southeast, with part of the West African mainland visible at the top of the image.
I really like these cubesats! Read whole description at the Aerospace Corporation website.
Comet Lovejoy from Andrew’s telescope. Click for larger. Credit: Andrew Dumont
The discussion with Andrew a couple of weeks ago must have struck a chord. On one of the first decent skies either of us have seen he went and took this image of the “real” Lovejoy.
The area around Comet Lovejoy from Stellarium.
If you want to go looking this should get you close:
RA: 8h31m34sec Dec: 16o04’28” or Az/Alt: 143o / 57o
Nice job Andrew!
Here is a video taken yesterday (02 Nov 13) of the Dream Chaser. The Dream Chaser is billed as a space taxi and it being built by Sierra Nevada Corporation.
This was a debut test flight for the spacecraft in California and while all appearances the flight went quite well right up to the end. You can see that there was a problem in the deployment of a wheel on the landing gear. The resulting skid of the unmanned vehicle was not shown.
You at first think this would be a setback, but I am willing to bet Sierra Nevada would not necessarily agree. sure there was a problem and they would be much more pleased if things went perfectly, however progressive companies tend not to dwell on the negatives as much as they do with learning how to avoid such instances in the future. It’s easy to see far more insight was gained than just the flight dynamics of Dream Chaser – they got to see what happens when things go bad.
Interesting to see the different approaches to space travel the private industry is brining to the table. Sierra Nevada Corp. may be only in the development phase of the Dream Chaser they are anything but new to space and other advanced technologies, for example they helped get the rover Curiosity on the surface of Mars. Check them out.
Fuzzy dice? Watch the video and you will know where that came from.
There will be a solar eclipse tomorrow 03 November 2013. I started out trying to explain who would see what but decided it would just be best to include a map. I’ve also included what should be a live feed you can watch on Sunday (hopefully).
This is a rather rare type of solar eclipse called a Hybrid Solar eclipse. This type of eclipse shifts between a total eclipse (when the moon completely covers the sun) and an annular eclipse (when the moon appears to be smaller and you can see a ring of solar disk around the edges of the moon).
A map of the extent of path of the Hybrid eclipse. Credit: NASA
The eclipse starts very early (about day break) for the eastern parts of North America and northern parts of South America. Central Africa will see the best eclipse but a wide swath north and south of there will get a decent look too.
Here’s that graphic above from NASA expanded with times
Since I’m in the “look quick and early” zone and with cloudy skies (and possibly snow) I will watch the best of it on the second video below.
Here’s a kind of a video version of the map:
Hopefully this video will work and if it does you should be able to watch the eclipse tomorrow live from the folks at Slooh:
Many thanks to Slooh for that excellent coverage!