Attachment letter

letter

REQUEST submitted by FCC,IB

letter

2005-05-24

This document pretains to SAT-STA-20050203-00018 for Special Temporal Authority on a Satellite Space Stations filing.

IBFS_SATSTA2005020300018_433943

Federal Communications Commission Washington, DC 20554 inematonal Borsnu May 24, 2005 Mr. Pantelis Michalopontos Steptoe & Johnson LLP 1330 Connectiont Avenve Washington, DC 20036—1795 Re: EchoStar Satelite LLC. Application for Special Temporary Authority To Move EchoStar 5 to 129° W.L. and To Conduct Telemety, Tracking and Command Operations During the Relacation to this Orbital Location. File Number: STA—STA—20050203—00018 Dear Mr. Michalopoulos, On May 11, 2005, on behalf of EchoStar Satellte LLC. (chostar, you submitted a leter in response to our request for additionalinformation in connection with the above—referenced application." In the May 11, 2005 letter, EchoStar states in Attachment 2 that "Two momentum wheel anomalies previously experienced require operation of the spacecraft in a modified earth—pointing mode uilizing thrusters to maintain spacecraft pointing.. While this operating mode provides adequate earth—pointing performance, it resuls in both an increase in fuel usage (with corresponding reduction of spacecraft life, and continuous operations of te digital integrated rate assemblies (DIRAs). Current toal DIRA on—times exceed those recommended by the spacecraft manifacturer.". This leads us to request the following additionalinformation: 1. Please provide a reliahlity analysis showing the probability offailure of the remaining momentum wheel, taking into account the failures of the frst two momentum wheels, and the resuling overall probability of being able to maintain spacecraft atitude control sufficient to provide DBS service and to not cause unacceptable interference to other systems due to mispointine 2. If failure of ts remaining momentum wheel would not require retiring EchoSar 5, what would be the impact of thisfailure on fuel consumption? 3. Please provide a reliablity analysis showing the probsbility offailure of the DIRAs, takinginto account the possiblity offailir ofthe remaining momentum wheel, an the resultng overall probabilty of being able to maintain spacecraft atitude control suffiient to provide DBS serviceand to not cause unaeceptable interference to other systems due to mispointing. 4. Please explain the impact a DIRA falure or failurs or the failure of the remaining momentum wheel would have on the abilty to properly dispose of the sateliteat the end of ts ‘ See Leterfrom Thomas S. Tyez, Chit, Stelite Division, Inmernationa! Burcas, to Pantlis Michalopoulos Counsel forEchaStar (Apr.4,2005)

mission life, or when spacecraft atitude control sufficient to provide DBS service and to not cause unacceptable interference to other systems due to mispointing is no longer easible Please provide the requested information by May 31, 2005. Failure to respond will subjectthe applicationto dismissal pursuantto Section 25,152 ofthe Commission‘s rules. Please hand.deliver or email courtesy copies of any fling made in response tothisleter to Karl Kensinger (KarlKensinger@fcc.gov) and Jay Whaley (ay.Whaley@cc.gov) of my staf. Sincerely, Shonss Sq ‘Thomas S.Tycz Chiet,Sutelite Division


Document Created: 2005-05-24 14:25:07
Document Modified: 2005-05-24 14:25:07
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