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ISEE-3 Satellite Is Back Under Control
brindafella writes: "Over the last two days, the (Reboot Project for the International Sun/Earth Explorer 3 (ISEE-3) satellite has successfully commanded ISEE-3 from Earth, using signals transmitted from the Aricebo Observatory. Signals were also received by cooperating dishes: the 21-meter dish located at Kentucky's Morehead State University Space Science Center; the 20-meter dish antenna in Bochum Observatory, Germany, operated by AMSAT Germany; and SETI's Allen Telescope Array, California. ISEE-3 was launched in 1978, and last commanded in 1999 by NASA. On May 15, 2014, the project reached its crowdfunding goal of US$125,000, which will cover the costs of writing the software to communicate with the probe, searching through the NASA archives for the information needed to control the spacecraft, and buying time on the dish antennas. The project then set a 'stretch goal' of $150,000, which it also met with a final total of $159,502 raised. The goal is to be able to command the spacecraft to fire its engines to enter an Earth orbit, and then be usable for further space exploration. This satellite does not even have a computer; it is all 'hard-wired.'"
I had written off this project as an impossible dream. Glad to say I was wrong.
This is an awesome accomplishment.
This satellite does not even have a computer; it is all 'hard-wired.'"
A lot of early computer systems were hard-wired in terms of instructions and logic paths. It didn't make them unusable, just arcane considering newer technologies like SoCs. We have come a long way.
Harrison's Postulate - "For every action there is an equal and opposite criticism"
some gates and circuits to detect and act on series of correct "control tones", the old definition of computer was anything that had input, transformed information, and presented to output (like analog computer, for instance).
Many young-uns think a "computer" needs to be a certain type of digital system with CPU, memory, IO bus and ports, etc.
As a young teen I read the manuals for a (defunct) satellite old retired engineer had, funny as electronics hobbyist I could understand it.
It's the Arecibo Observatory, not "Aricebo". Does it hurt to check the spelling?
I thought this was all an idealistic dream of some space nerds.
It looks like they just might pull this off ! I'm seriously impressed!
And as for not having a computer on board - that probably greatly increases the odds of it working after all these years. Space is harsh on electronics...
http://xkcd.com/1337/
It was certainly nice that this was approved with a great deal of speed by all the agencies involved. Good news too that they were able to preempt other previously approved projects.
But in reality, it sounds like they had an excellent plan and at least some proof-of-concept design done when it was pitched to those agencies. Also, it's pretty time-sensitive and a great PR win if it succeeds, which the space industry desperately needs right now.
When the grease is available, all those wheels of government can turn pretty quickly!
As a proud contributor to the ISEE-3 reboot project, I'd like to highlight that after communicating with the satellite, they discovered that the trajectory was over 200,000 km off where the predictions indicated it should be and its trajectory was specifically placing it in danger of impacting the moon. I would like to congratulate the ISEE-3 team on helping avoid a man-made impact with our moon.
(double post due to not being logged in)