Final, S2740 Respons

LETTER submitted by DISH Operating L.L.C.

Letter Response to 13 Sept Inquiry

2012-09-28

This document pretains to SAT-MOD-20100329-00058 for Modification on a Satellite Space Stations filing.

IBFS_SATMOD2010032900058_967989

Pantelis Michalopoulos 202 429 6494 pmichalopoulos@steptoe.com 1330 Connecticut Avenue, NW Washington, DC 20036-1795 202 429 3000 main www.steptoe.com September 28, 2012 VIA IBFS Marlene H. Dortch Secretary Federal Communications Commission 445 12th Street, SW Washington, DC 20554 Re: DISH Operating LLC; File Nos. SAT-MOD-20100329-00058, SAT-AMD-20100610-00127 (Call Sign 2740) Dear Ms. Dortch: With this letter, DISH Operating LLC (“DISH”) responds to the September 13, 2012 letter from the Robert Nelson, Chief, Satellite Division of the International Bureau, requesting additional information regarding EchoStar 7’s orbital debris mitigation plan. Specifically, the September 13th letter asks DISH to identify each tank on the spacecraft that will not be vented or have its pressure relieved upon disposal of the spacecraft, and for each such tank, provide: • the volume of the tank, • the propellants and/or pressurants left in the tank, identified by their chemical names, • the mass of each propellant or pressurant left in the tank, • the expected maximum internal temperature of the tank in the disposal orbit, and • the expected maximum internal pressure of the tank in the disposal orbit. The letter also asks DISH to explain whether the oxidizer tanks are currently sealed or unsealed, and if the tanks were sealed, to indicate when they were sealed, and if the tanks were not sealed, to state when they will be sealed. Finally, the letter asks whether the analysis of disposal options outlined for the EchoStar 4 satellite in IBFS File No. SAT-STA-20110627-00122 is also applicable with respect to EchoStar 7.

Marlene H. Dortch September 28, 2012 Page 2 There are four tanks on the EchoStar 7 satellite that will not be vented to depletion at spacecraft end-of-life (“EOL”). These four tanks and their relevant data are as follows: Max Internal Max Internal Tank Volume Propellant/ Mass Remaining Pressure, Tank Temp, Disposal (in3) Pressurant (kg) Disposal Orbit (C) Orbit (psia)1 Oxidizer 20,017.5 N2O4 39.8 (amount 35 295 Tank #1 remaining between Oxidizer 20,015.2 N2O4 the 2 oxidizer 35 295 Tank #2 tanks)2 Pressurant 4,234.8 He 0.558 (amount 35 500 Tank #1 remaining between Pressurant 4,242.4 He the 2 pressurant 35 500 Tank #2 tanks)3 1 These pressures are far below the respective margins for the burst pressure for these tanks. 2 Relatively efficient orbit raising resulted in slightly larger-than-expected-amounts of remaining oxidizer on the spacecraft. 3 The remaining gaseous Helium is a residual amount expected to persist after the final repressurization of the hydrazine tank before EOL maneuvers. The oxidizer tanks were sealed with pyrotechnic valves upon completion of in-orbit testing on March 7, 2002. DISH expects EchoStar 7 to provide a full lifetime of commercial service, leaving only enough remaining hydrazine, with appropriate margins, to achieve the disposal orbit of 350 km minimum perigee. The above figures for the oxidizer and pressurant tanks represent the estimated values expected upon completion of all EOL procedures. Please let me know if you have further questions. Respectfully submitted, /s/ Pantelis Michalopoulos Counsel for DISH Operating LLC cc: Kathyrn Medley, FCC Karl Kensinger, FCC Howard W. Waltzman, Mayer Brown LLP David Wilson, Spectrum Five LLC


Document Created: 2012-09-28 15:21:55
Document Modified: 2012-09-28 15:21:55
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