Human spaceflight has always been, and still remains, a risky endeavor. We mitigate risk by being as prepared as we can. Every activity is planned, reviewed, and practiced long before any rocket engines are ignited. But space has a history of not cooperating with plans, and thus there is a corresponding history of hacks to get missions back on track. YouTube space fan [Scott Manley] recaps some of his favorites in How a $2 Toothbrush Saved the ISS and Other Unbelievable Space Hacks.
The introduction explained this compilation was motivated by the latest International Space Station drama, where an elusive air leak has finally been tracked down. Air leaks are obviously much more worrying in a space station than in, say, a bicycle tire. Thus there exists a wide array of tools to track down leaks but they couldn’t find this one. Reportedly the breakthrough came from an improvised airflow visualization tool: leaves from a cut-open tea bag. Normally small floating particles are forbidden in space because they might end up in troublesome places. (Eyes, noses, onboard equipment…) Apparently the necessity of the hack outweighed the rules here.
Tea leaves are but the latest in a long line of hacks devised in the course of space missions, because things don’t always go according to the original plan. Or even any of the large volume of contingency plans. Solutions have to be cobbled together from resources on hand, because when we’re in space, what we brought is all we have. From directly editing production code during Apollo 14, to a field-built replacement fender for the Apollo 17 Lunar Rover Vehicle (top picture), to the $2 toothbrush pressed into service as metal debris cleaner. The mission must go on!
Continue reading “Short Video Recaps A Long Tradition Of Space Hacks”
The Apollo missions still inspire people today, decades after they took place. A fortunate side effect of the global public relations campaign is that a lot of information is publicly available for us to review and process. We’re right around the 49th anniversary of Apollo 14 mission, so it was a good time for [Frank O’Brien] to take readers through Apollo Guidance Computer and the hack that saved Apollo 14 (while it was in lunar orbit).
Space fans would already know many parts of this piece, but [Frank] weaves it together into a single narrative around a problematic “Abort” button that was found to be making intermittent contact as the crew were preparing to land on the moon. An inconvenient timing would have unnecessarily aborted the mission, which was obviously Not Good. [Frank] brings us up to speed on AGC fundamentals, just enough to understand the technical constraints for the hack, devised within the time constraints they faced.
For those that prefer a short video summary [Scott Manley] covered this same hack on YouTube. And for another perspective on the scope of this task, remember this was years before we had vi or emacs. When they were contemplating flipping status bits as programs were running, it’s not trivial to do a global search for code that might examine those bits. Look at the tome of source code AGC programmer [Don Eyles] worked with. Space fans who want to learn more can check out [Don]’s book.
For the ultimate AGC talk, check out The Ultimate AGC Talk.
Maybe someday trips to the moon will be a commonplace thing, but Apollo will always be the pioneer.
The most computationally intense part of an Apollo mission was the moon landing itself, requiring both real-time control and navigation of the Lunar Module (LM) through a sequence of programs known as the P60’s. Data from radar, inertial navigation, and optical data sighted-off by the LM commander himself were fed into the computer in what we’d call today ‘data fusion.’
The guy who wrote that code is Don Eyles and the next best thing to actually hanging out with Don is to read his book. Don’s book reads as if you are at a bar sitting across the table listening to his incredible life story. Its personal, hilarious, stressful, fascinating, and more importantly for those of us who are fans of Hackaday, it’s relatable.
Continue reading “Books You Should Read: Sunburst And Luminary, An Apollo Memoir”
Deep-voiced and aptly named [Scott Manley] posted a video about the computer hack that saved Apollo 14. Unlike some articles about the incident, [Scott] gets into the technical details in an entertaining way. If you don’t remember, Apollo 14 had an issue where the abort command button would occasionally signal when it shouldn’t.
The common story is that a NASA engineer found a way to reprogram the Apollo guidance computer. However, [Scott] points out that the rope memory in the computer wasn’t reprogrammable and there was no remote way to send commands to the computer anyway.
Continue reading “The Longest Tech Support Call: Apollo 14 Computer Hack”