BUSEK PRESS RELEASE Busek’s Hall Effect Thruster Technology saves Air Force AEHF satellite Natick, Massachusetts - March 25, 2012 The Advanced Extremely High Frequency or AEHF satellite was launched Aug. 14, 2010, suffered a serious setback when the spacecraft's  main propulsion subsystem failed.  The very large and expensive $2 billion military communications satellite could have died a quick death,  except Busek's Hall effect thruster technology saved it from becoming space junk.   The AEHF program, one of the largest space programs of the decade, is designed to augment and eventually replace the legacy Milstar  satellite communications network.  This satellite is the first of a constellation of satellites planned to support military operations from  geosynchronous orbit (GEO).  ULA (United Launch Alliance, a Busek partner) spacecraft launch went as expected into a highly elliptical  orbit (HEO at 147 by 31,000 miles).  This nominal transfer orbit was to be circularized to a stationary orbit at some 23,000 miles.  But soon  after launch something went terribly wrong.  The 13,420-pound satellite was to be transferred from HEO to GEO using the satellite's hydrazine-fueled liquid apogee engine (LAE).   However the LAE malfunctioned due to a propellant line blockage.   The LAE thruster was supposed to raise the spacecraft to 11,800 miles  in a short period.  At that point other spacecraft engines would then take over and continue the orbit circularization.  Without the larger LAE  engines available, a recue mission by the Space and Missile Systems Center (Los Angeles AFB) and prime contractor Lockheed Martin  devised a plan to boost the errant AEHF satellite.   Also future AEHF satellites launches were put on hold under the issue was resolved.  To raise the orbit of the spacecraft, the team utilized the smaller propulsion systems on the spacecraft.  The first of these were hydrazine-  fueled reaction engine assemblies (REAs).  While raising the orbit to nearly 3000 miles these engines was possible, they are not designed  to run for long periods of time and soon failed.  It eventually fell to xenon-fueled Hall thrusters technology, pioneered in the US by Busek  Co. Inc, Natick, MA, to complete the push to GEO.  Busek's Hall thruster technology was licensed to Primex Aerospace, now Aerojet, a  GenCorp Company.  Aerojet manufactured the AEHF Hall thrusters under the designation BPT-4000.  (BPT stands for Busek-Primex  Thruster.)  Operating at about 0.05 pounds of thrust for many hours each day propelled the AEHF to its assigned orbital slot and eventually saved the day.  The Hall effect thrusters were pressed into operation much earlier and much longer than planned but the $2B AEHF was  saved.  The Air Force expects AEHF to enter full operational service in March and now the second AEHF is scheduled for a May launch  date. ABOUT BUSEK CO. INC. Busek Co. Inc. is a privately held advanced space system company located in Natick, Massachusetts. For over 25 years Busek has  provided a wide range of thrusters, electronics, space systems, research and complete mission and system engineering support for  customers including the major aerospace primes, NASA and the US Air Force.  Busek flight heritage includes products developed for AFRL  TacSat-2, USAFA FalconSat-3, FalconSat-5, and NASA/ESA Lisa Pathfinder.  In the late nineties, Busek licensed its Hall thruster  technology to Aerojet Corp. that produced the BPT-4000 Hall thruster now flying on the Advanced EHF satellite. Distribution Statement "A" (Approved for Public Release, Distribution Unlimited) CONTACT: W. Dan Williams, Ph.D.   Director of Business Development   wdanwilliams@busek.com
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