Embedded Systems Conference
Breaking News
Comments
Newest First | Oldest First | Threaded View
Page 1 / 2   >   >>
David Ashton
User Rank
Author
re: Chips in Space: Letís look inside ARISSat-1 (part 2)
David Ashton   8/27/2011 9:33:08 AM
NO RATINGS
Hmmm..that is exraordinary.. I've had batteries go open and short, but not both...then again I've never kept a shorted one (that I could not recover) for 20 years either. With solar panels, supercapacitors and a bit of intelligent circuitry, it should be possible to give dodgy NiCds a "zap" of high current charge if it looks bad when the sat comes out of eclipse. Would it be possible to work with supercaps alone - I would emagine the eclipse periods are not very long? I'd think supercaps have a better lifespan than the best batteries?

jdesbonnet
User Rank
Author
re: Chips in Space: Letís look inside ARISSat-1 (part 2)
jdesbonnet   8/26/2011 1:41:00 AM
NO RATINGS
I would imagine that Li-ion was out because the satellite had to be stored inside the ISS alongside the astronauts for several months. So any battery technology capable of leaking, outgassing or bursting into flames is certainly a no no. Although I do see lots of Thinkpads in photos of the ISS... Do they have Li-ion battery packs?

Steve Bible
User Rank
Author
re: Chips in Space: Letís look inside ARISSat-1 (part 2)
Steve Bible   8/25/2011 5:40:31 PM
NO RATINGS
This particular battery was designed with high reliability in mind, not longevity. The number of charges and discharges are carefully monitored. After the specified number are met, the battery is disposed of.

Steve Bible
User Rank
Author
re: Chips in Space: Letís look inside ARISSat-1 (part 2)
Steve Bible   8/25/2011 5:38:21 PM
NO RATINGS
Hi R.D., yes it is a tale of making do with what you have. Yes, we would like to make the battery system robust. We learned a lot from ARISSat-1 and we will be exploring new ideas.

Steve Bible
User Rank
Author
re: Chips in Space: Letís look inside ARISSat-1 (part 2)
Steve Bible   8/25/2011 5:35:21 PM
NO RATINGS
Hi Sanjib, it is true that FPGA manufactures make radiation hardened components for the aerospace industry. They are very expensive for an amateur project. Thus we chose to go the cheap and easy route. I do believe that we shall see the proof of the pudding (as it were) with ARISSat-1. Letís see how long it operates with industrial temperature grade components. On the question of temperature specification, simulations were telling us the range of -20 to +40 degrees C. However, we are seeing in the telemetry higher temperatures. We are still investigating why that is.

Steve Bible
User Rank
Author
re: Chips in Space: Letís look inside ARISSat-1 (part 2)
Steve Bible   8/25/2011 5:30:06 PM
NO RATINGS
Hi David, I only mention NiCad because past amateur satellites have flown them with good results. In other words, itís something we know. But we would like to explore other chemistries and charging management methods to both learn and expand our level of knowledge Ė within the safety boundaries we are given. If you look at past amateur satellites and their battery track records, the life of each most often is dictated by the battery. As you mentioned, they like to short which renders the satellite power system inoperable. If we could have a smart system that could remove the short, at least we can continue to operate in the Sun; my like ARISSat-1 is doing now. We were lucky; it appears that the battery failed open. For an extraordinary story, take a look at the life of OSCAR 7. It was rendered dead for several years because of a shorted battery. Then one day it was discovered operating in sunlight. http://en.wikipedia.org/wiki/Oscar_7

mspitze
User Rank
Author
re: Chips in Space: Letís look inside ARISSat-1 (part 2)
mspitze   8/24/2011 5:58:01 PM
NO RATINGS
Would hate to be the poor Cosmonaut that gets failed battery for his his life support systems.

Sanjib.A
User Rank
Author
re: Chips in Space: Letís look inside ARISSat-1 (part 2)
Sanjib.A   8/24/2011 3:18:43 AM
NO RATINGS
Hi Steve, thanks a lot for the information. While browsing through the parts e.g FPGAs, controller, I've seen some manufacturer sells "radiation hardened" chips. Do you really need them? They are usually sold at a premium. Also, what is the environmental spec. (temperature etc.) for which you design your electronics?

David Ashton
User Rank
Author
re: Chips in Space: Letís look inside ARISSat-1 (part 2)
David Ashton   8/24/2011 12:47:25 AM
NO RATINGS
Thanks Steve. Interesting you mention NiCds, I would have thought you'd go for something like Li-ion? I'm quite a fan of NiCds,but it's mainly as I have access to lots of them. If you look after them they are good batteries...but they do have an annoying habit of going permanently short circuit if they are left discharged for any time....which, as with your current battery's problems, would be disastrous. Any reason for choosing NiCd?

Robotics Developer
User Rank
Author
re: Chips in Space: Letís look inside ARISSat-1 (part 2)
Robotics Developer   8/23/2011 2:58:29 PM
NO RATINGS
Bummer about the battery!! It seems that (in hindsight) a backup/redundant storage system would have been in order. Is there any consideration for a low power down standby/hibernate mode for the next satellite? This coupled with a small redundant power backup could be used to enable the electronics to not get reset during short periods of eclipse. Thanks for the details! A classic case of "this is what we have to work with" and making due. Keep up the good work.

Page 1 / 2   >   >>


Most Recent Comments
Radio
LATEST ARCHIVED BROADCAST
Overview: Battle-hardened veterans of the electronics industry have heard of the ďconnected carĒ so often that they assume itís a done deal. But do we really know what it takes to get a car connected and what its future entails? Join EE Times editor Junko Yoshida as she moderates a panel of movers and shakers in the connected car business. Executives from Cisco, Siemens and NXP will share ideas, plans and hopes for connected cars and their future. After the first 30 minutes of the radio show, our listeners will have the opportunity to ask questions via live online chat.
Flash Poll
Like Us on Facebook

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)
Special Video Section
LED lighting is an important feature in todayís and future ...
Active balancing of series connected battery stacks exists ...
After a four-year absence, Infineon returns to Mobile World ...
A laptopís 65-watt adapter can be made 6 times smaller and ...
An industry network should have device and data security at ...
The LTC2975 is a four-channel PMBus Power System Manager ...
In this video, a new high speed CMOS output comparator ...
The LT8640 is a 42V, 5A synchronous step-down regulator ...
The LTC2000 high-speed DAC has low noise and excellent ...
How do you protect the load and ensure output continues to ...
General-purpose DACs have applications in instrumentation, ...
Linear Technology demonstrates its latest measurement ...
10:29
Demos from Maxim Integrated at Electronica 2014 show ...
Bosch CEO Stefan Finkbeiner shows off latest combo and ...
STMicroelectronics demoed this simple gesture control ...
Keysight shows you what signals lurk in real-time at 510MHz ...
TE Connectivity's clear-plastic, full-size model car shows ...
Why culture makes Linear Tech a winner.
Recently formed Architects of Modern Power consortium ...
Specially modified Corvette C7 Stingray responds to ex Indy ...