Tom.Hocking@bbs.acs.unc.edu (Tom Hocking) (04/14/91)
According to my list of NASA Acronyms, APU stands for "Auxiliary Power Unit." However, the shuttle needs them to generate power any time the orbiter is not attached to umbilicals. -- Tom Hocking Education Coordinator Morehead Planetarium University of North Carolina at Chapel Hill starman@unc.bitnet Tom.Hocking@bbs.acs.unc.edu -- ============================================================================= Extended Bulletin Board Service, Research & Development Office of Information Technology, University of North Carolina at Chapel Hill internet: bbs.acs.unc.edu or 128.109.157.30
jonkatz@gn.ecn.purdue.edu (Jonathan W. Katz) (04/14/91)
In article <3331@beguine.UUCP> Tom.Hocking@bbs.acs.unc.edu (Tom Hocking) writes: > >According to my list of NASA Acronyms, APU stands for "Auxiliary Power >Unit." However, the shuttle needs them to generate power any time the >orbiter is not attached to umbilicals. > >-- That's not quite true. The APU's are needed during ascent and descent to power the hydraulic systems. The orbiter gets the majority of its electrical power from three fuel cells that convert hydrogen and oxygen to electricity and water.
clj@ksr.com (Chris Jones) (04/15/91)
In article <3331@beguine.UUCP>, Tom.Hocking@bbs (Tom Hocking) writes: > >According to my list of NASA Acronyms, APU stands for "Auxiliary Power >Unit." However, the shuttle needs them to generate power any time the >orbiter is not attached to umbilicals. > The shuttle uses fuel cells to generate its electrical power. During launch and landing, it needs auxillary power to move its aerodynamic control surfaces and gimbal its main engines. The three APUs provide this power. They are turned on 5 minutes before launch, turned off about 12-1/2 minutes after launch, turned back on about 3 minutes before the deorbit burn (approximately 1 hour before landing) and turned back off again 2 minutes after landing. -- Chris Jones clj@ksr.com {uunet,harvard,world}!ksr!clj
edotto@ux1.cso.uiuc.edu (Ed Otto) (04/15/91)
Tom.Hocking@bbs.acs.unc.edu (Tom Hocking) writes: >According to my list of NASA Acronyms, APU stands for "Auxiliary Power >Unit." However, the shuttle needs them to generate power any time the >orbiter is not attached to umbilicals. The APU, or Auxilary Power Unit, does NOT provide 'power'...it provides hydraulic pressure to move the elevons and gimbal the engines, etc. The electricity on-board the shuttle is provided by means of several fuel cells located under the mid-deck. ******************************************************************************* * * Netmail addresses: * * Edward C. Otto III * edotto@uipsuxb.ps.uiuc.edu * * University of Illinois * edotto@uiucux1.cso.uiuc.edu * * Printing Services Office * UIPSA::OTTO (Decnet node 46.99) * * 54A E. Gregory Dr. * otto@uipsa.dnet.nasa.gov * * Champaign, IL 61820 * Office phone: 217/333-9422 * * * * ******************************************************************************* "As knowledge is to ignorance, so is light unto the darkness." --- GO 'PODS! --- -- ******************************************************************************* * * Netmail addresses: * * Edward C. Otto III * edotto@uipsuxb.ps.uiuc.edu * * University of Illinois * edotto@uiucux1.cso.uiuc.edu *