REG NASA-LLIS-1864-2008 Lessons Learned - External filter needed to achieve low EMI from TWTA.pdf

1、Lessons Learned Entry: 1864Lesson Info:a71 Lesson Number: 1864a71 Submitting Organization: GRCa71 Submitted by: Dale Forcea71 POC Name: Dale Forcea71 POC Email: Dale.A.Forcenasa.gova71 POC Phone: 216-433-3520Subject: External filter needed to achieve low EMI from TWTA Abstract: The Lunar Reconnaissa

2、nce Orbiter required lower levels of Electromagnetic Interference (EMI) than usual to avoid causing sensitive components to malfunction. It was found necessary to use an external filter between the bus and the EPC of the TWTA to obtain the needed level of EMI.Description of Driving Event: The Lunar

3、Reconnaissance Orbiter needed low levels of Electromagnetic Interference from its components. Preliminary measurements indicated that the traveling wave tube amplifier (TWTA) would not meet the requirements. Therefore, the input filter on the electronic power conditioner (EPC) was redesigned, giving

4、 excellent EMI rejection in the breadboard. However, when the protoflight unit was tested, the EMI was slightly worse then the preliminary measurements. This was found to be due to RF paths created when the unit was packaged in its metal box. An external filter was designed which reduced the EMI by

5、more than 30 dB, allowing the TWTA to be integrated with the LRO satellite passing all system tests.Lesson(s) Learned: A filter external to the Electronic Power Conditioner (EPC) of a traveling wave tube amplifier (TWTA) is needed to obtain lower levels of Electromagnetic Interference (EMI).Recommen

6、dation(s): Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Missions using TWTAs and needing low levels of EMI should incorporate an external filterbetween the TWTA and the spacecraft bus.Evidence of Recurrence Control Effectiveness: We expect to use

7、an external filter in the Communications, Navigation, and Networking reConfigurable Testbed, a program using a TWTA built to the LRO design, which will fly on the International Space Station (ISS).Documents Related to Lesson: N/AMission Directorate(s): a71 Space Operationsa71 Sciencea71 Exploration

8、SystemsAdditional Key Phrase(s): a71 Engineering Design (Phase C/D).Spacecraft and Spacecraft Instrumentsa71 Integration and TestingAdditional Info: a71 Project: Lunar Reconnaissance OrbiterApproval Info: a71 Approval Date: 2008-09-26a71 Approval Name: mbella71 Approval Organization: HQProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-