<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Busek is a pretty interesting local company who makes Hall-effect thrusters. I found this on their website:<div class=""><br class=""></div><div class="">Why use Hall-effect thrusters?<div class=""><br class="">Hall thrusters generate thrust by creating and accelerating ionized gas via an electric field. Confined within a finely shaped magnetic field, electrons gyrorotate within the channel until they ionize a neutral atom. The ionized plasma is then accelerated by the electric field to exhaust velocities of greater than 25,000 m/s. <br class=""><br class="">With no moving mechanical parts and a simple electrical layout, Hall thrusters are extremely reliable; no on-orbit thruster failures have been reported to-date. <br class=""><br class="">The high specific impulse of Hall thrusters leverages the nonlinear nature of the rocket equation. Every additional second of specific impulse leads to an exponential improvement in the spacecraft mass ratio. <br class=""><br class="">While the best existing chemical engines have a specific impulse of around 400 s, our high power thrusters have over 2500 s. For the same propellant mass fraction, a spacecraft with our Hall Thrusters will have over 6x the delta-V. Without the space-charge limitations that are encountered when using some other EP technologies, Hall thrusters are compact and offer the optimum balance of high specific impulse and thrust-to-power. Electric propulsion is mission-enabling, and allows for unprecedented amounts of flexibility for orbit raising, cislunar maneuvers, interplanetary transfers and beyond. <div class=""><br class=""></div><div class=""><a href="https://www.busek.com/hall-thrusters" class="">https://www.busek.com/hall-thrusters</a></div><div class=""><br class=""></div><div class=""><div class="">
<meta charset="UTF-8" class=""><div dir="auto" style="text-align: start; text-indent: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div dir="auto" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div style="text-align: start; text-indent: 0px;">Stephen Quatrano<br class="">CEO and Cofounder | Meema, Inc<br class="">web: <a href="http://meemastories.com" class="">http://meemastories.com</a><br class=""><a href="mailto:stephen.quatrano@meemastories.com" class="">email: stephen.quatrano@meemastories.com</a><br class="">cell: +1 781-266-8799<br class="">https://www.linkedin.com/in/quatrano/<br class=""><br class="">Board Member | The Right Question Institute<br class="">http://www.rightquestion.org<br class=""><br class="">Lifelong Learner<br class="">http://www.howdoweknow.info/p/home.html<br class="">https://stefano.quatrano.us/2004/05/antonios-liberation-story-by-steve.html</div></div></div>
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<div><br class=""><blockquote type="cite" class=""><div class="">On Oct 11, 2023, at 4:27 PM, John Rudy via LCTG <<a href="mailto:lctg@lists.toku.us" class="">lctg@lists.toku.us</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta charset="UTF-8" class=""><div class="WordSection1" style="page: WordSection1; caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;"><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><span style="font-size: 14pt; font-family: Arial, sans-serif;" class="">I just read this 3 times and still don’t understand it. Of course there is a sentence in the middle that reminds me of my high school teacher’s “the proof will be left to the reader”.<o:p class=""></o:p></span></div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><span style="font-size: 14pt; font-family: Arial, sans-serif;" class="">John<o:p class=""></o:p></span></div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><span style="font-size: 12pt; font-family: Arial, sans-serif;" class="">================================================== <span class="Apple-converted-space"> </span><o:p class=""></o:p></span></div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><span style="font-size: 12pt; font-family: Arial, sans-serif;" class=""><o:p class=""> </o:p></span></div><p class="MsoNormal" style="margin: 0in 0in 8.4pt; font-size: 11pt; font-family: Calibri, sans-serif; line-height: 22.5pt; background-color: white; vertical-align: baseline;"><b class=""><span style="font-size: 18pt; font-family: "Open Sans", sans-serif; color: rgb(51, 51, 51);" class="">Sci-fi propulsion is now a reality<o:p class=""></o:p></span></b></p><p class="MsoNormal" style="margin: 0in 0in 12pt; font-size: 11pt; font-family: Calibri, sans-serif; background-color: white; vertical-align: baseline;"><span style="font-size: 12pt; font-family: "Open Sans", sans-serif; color: rgb(51, 51, 51);" class="">David Oh, chief engineer for operations at NASA's Jet Propulsion Laboratory says this will be the first-ever mission to use Hall Effect thrusters in interplanetary space. What does that mean? Well basically, Hall Effect thrusters use electricity to ionize xenon gas — ionization refers to removing or adding one or two electrons from the atoms that make up a substance. In this case, the substance is a gas. <o:p class=""></o:p></span></p><p class="MsoNormal" style="margin: 0in 0in 12pt; font-size: 11pt; font-family: Calibri, sans-serif; background-color: white; vertical-align: baseline;"><span style="font-size: 12pt; font-family: "Open Sans", sans-serif; color: rgb(51, 51, 51);" class="">Upon ionization, those atoms gain a charge. (Regular old atoms have neutral charges because their positive proton count and negative electron count are equal. Remove some electrons, for instance, and you lose some negativity.) The result? Ions. Then, those charged ions form an electric field which can, through a series of complicated steps, propel an object. In this case, that's the Psyche spacecraft. <o:p class=""></o:p></span></p><p class="MsoNormal" style="margin: 0in 0in 12pt; font-size: 11pt; font-family: Calibri, sans-serif; background-color: white; vertical-align: baseline;"><span style="font-size: 12pt; font-family: "Open Sans", sans-serif; color: rgb(51, 51, 51);" class="">"They come out of the thruster going at 15 kilometers per second, or nine miles per second," Oh said. "That's five times faster than the speed of the fuel coming out of a regular chemical rocket."<o:p class=""></o:p></span></p><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><span style="font-size: 12pt; font-family: Arial, sans-serif;" class=""><o:p class=""> </o:p></span></div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><span style="font-size: 12pt; font-family: Arial, sans-serif;" class=""><o:p class=""> </o:p></span></div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><span style="font-size: 10pt; font-family: Arial, sans-serif;" class="">John Rudy<o:p class=""></o:p></span></div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><span style="font-size: 10pt; font-family: Arial, sans-serif;" class=""><o:p class=""> </o:p></span></div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><span style="font-size: 10pt; font-family: Arial, sans-serif;" class="">781-861-0402<o:p class=""></o:p></span></div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><span style="font-size: 10pt; font-family: Arial, sans-serif;" class="">781-718-8334 cell<o:p class=""></o:p></span></div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><span style="font-size: 10pt; font-family: Arial, sans-serif;" class="">13 Hawthorne Lane<o:p class=""></o:p></span></div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><span style="font-size: 10pt; font-family: Arial, sans-serif;" class="">Bedford MA<o:p class=""></o:p></span></div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><span style="font-size: 10pt; font-family: Arial, sans-serif;" class=""><a href="mailto:jjrudy1@comcast.net" class="">jjrudy1@comcast.net</a><o:p class=""></o:p></span></div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><span id="cid:image001.png@01D9FC5F.D2931ED0"><image001.png></span><span style="font-size: 10pt; font-family: Arial, sans-serif;" class=""><o:p class=""></o:p></span></div><div style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;" class=""><o:p class=""> </o:p></div></div><span style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; float: none; display: inline !important;" class="">===============================================</span><br style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; 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