CHALLENGER'S LOST LESSONS - ER - NASA

44For Additional StudyThe Electromagnetic Chamber DemonstrationThe experiment featured above can be readily performedusing an iron magnet, but Christa’s lost magnetic lesson employed anelectro-magnet. For those wanting a more ambitious investigationwith an experiment more closely replicating that proposed forChrista, the following demonstration is offered:To begin, carefully examine the above videos to grasp anunderstanding of how the magnetic chamber was designed. Notethat the electromagnet axially passes through the enclosed volume.Of course, in zero-g, the iron filings must be held within thechamber, otherwise, they might be inhaled by the crew. Though thezero-g practice used the inflated chamber, obviously, electricalcurrent was not applied. The iron filings do not appear to cling tothe centered iron rod whatsoever. In fact, they randomly sail aboutthe enclosure, or, act together as an inertial mass responding to themotion imparted to the chamber by Christa and others. (Watchingthe above videos explains exactly why there is no clinging of filingsto the electromagnet. The ground demonstration includes the batterypack for the electromagnet. The zero-g practice does not.)The nature of zero-g KC-135 practices allows less than a halfminute per parabolic gravity-less maneuver. While this might havebeen sufficient to observe the lines-of-force pattern, the jostling ofthe apparatus would have made success problematical. However, onorbit, Christa would not face such a handicap. Plenty of time wouldbe available to establish the effect of the electromagnet’s lines offorce on the iron filings. (In the video Christa speaks of having twoand one half minutes to orient the chamber in various attitudes toexamine the pattern the iron filings assume with the application ofelectro-magnetism. She suggests examining on film what happens ifshe releases the chamber to “free-flow” across the Challenger’scabin. Indeed, Christa is making a significant scientific contributionto the Magnetic Lost Lesson demonstration. This would be much likethe previous experiment. The soda bottle chamber was turned overand rotated so that the magnetic field could draw the iron filings into