Phoenix - spring images, HiRISE views of Phoenix after the long, long winter |
Phoenix - spring images, HiRISE views of Phoenix after the long, long winter |
Oct 26 2009, 02:14 PM
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Solar System Cartographer Group: Members Posts: 10229 Joined: 5-April 05 From: Canada Member No.: 227 |
Doug just said in another thread that he was looking for Phoenix in the new images and couldn't find it. Well, I love a challenge. So here it is:
Close-up: (REMOVED - SEE LATER POST) Context: (REMOVED - SEE LATER POST) Note that map-projected HiRISE images at this latitude are in polar stereographic projection, not a cylindrical projection. North is at the left. You might not believe this, but by blinking layers like Clyde Tombaugh I think I can match numerous points, not just the hardware. EDIT: I was a bit off. Correct locations are shown below. Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PDF: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Jan 12 2010, 10:24 PM
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Director of Galilean Photography Group: Members Posts: 896 Joined: 15-July 04 From: Austin, TX Member No.: 93 |
The other thing to think about is that the 18th is the earliest an optimist would expect a reponse. Phoenix stopped transmitting at about the same sun angle, on the way to winter, which means that it's batteries were supplying power and probably extended the time she could send. On the way out of winter, the batteries are going to be dead, and so will not be supplying any extra juice to get her signal out. I'm sure her power management hardware actively controls the battery charging, but I'm not sure how much control the software has over that coming up from a completely dead state, ie the power manager circuit might start trickle charging the battery to raise the voltage well before the CPU comes out of reset. In some cases, such as mobile phones, a charged battery is required for the transmitter to work, since the transmitter uses much more instantaneous power than the wall charger can provide. If you read his description, he does state that the lander waits 19 hours between 2 hour listening windows, for Lazarus mode to cycle the listening window across the whole day because the on-board clock would be reset. For that, the batteries do need a charge. So, my expectation is that the lander will need to wait significantly past the Jan. 18th minimum sol altitude to charge up the batteries enough to last through the night.
-------------------- Space Enthusiast Richard Hendricks
-- "The engineers, as usual, made a tremendous fuss. Again as usual, they did the job in half the time they had dismissed as being absolutely impossible." --Rescue Party, Arthur C Clarke Mother Nature is the final inspector of all quality. |
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Jan 13 2010, 12:14 AM
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Senior Member Group: Members Posts: 2542 Joined: 13-September 05 Member No.: 497 |
Phoenix stopped transmitting at about the same sun angle, on the way to winter, which means that it's batteries were supplying power and probably extended the time she could send. I'm not convinced of that since the accounts suggest the batteries were dead at wakeup from running heaters overnight. At any rate, the batteries are very likely to be useless from being frozen at zero charge -- http://www.edn.com/blog/1470000147/post/510028451.html -- so I think we will probably not be able to use them. I think PHX can transmit with a dead battery. One could look at when the ODY overflights are relative to when one would expect max power on the panels to figure out what the most likely recovery time would be. -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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