국내 최대 기계 및 로봇 연구정보

기술보고서

기술보고서 게시판 내용
타이틀	Integration Assessment of Visiting Vehicle Induced Electrical Charging of the International Space Station Structure
저자	Kramer, Leonard;; Kerslake, Thomas W.;; Galofaro, Joel T.
Keyword	CREW EXPLORATION VEHICLE;; ELECTRIC POTENTIAL;; ELECTRIC POWER;; ELECTROSTATIC PROBES;; HAZARDS;; INTERNATIONAL SPACE STATION;; LOW EARTH ORBITS;; MAGNETIC INDUCTION;; MATHEMATICAL MODELS;; PLASMA INTERACTIONS;; SIMULATION;; SOLAR ARRAYS;; SPACE STATION STRUCTURES;; SYSTEMS ENGINEERING
URL	http://hdl.handle.net/2060/20110003058
보고서번호	NASA/TM-2010-216901
발행년도	2010
출처	NTRS (NASA Technical Report Server)
ABSTRACT	The International Space Station (ISS) undergoes electrical charging in low Earth orbit (LEO) due to positively biased, exposed conductors on solar arrays that collect electrical charges from the space plasma. Exposed solar array conductors predominately collect negatively charged electrons and thus drive the metal ISS structure electrical ground to a negative floating potential (FP) relative to plasma. This FP is variable in location and time as a result of local ionospheric conditions. ISS motion through Earth s magnetic field creates an addition inductive voltage up to 20 positive and negative volts across ISS structure depending on its attitude and location in orbit. ISS Visiting Vehicles (VVs), such as the planned Orion crew exploration vehicle, contribute to the ISS plasma charging processes. Upon physical contact with ISS, the current collection properties of VVs combine with ISS. This is an ISS integration concern as FP must be controlled to minimize arcing of ISS surfaces and ensure proper management of extra vehicular activity crewman shock hazards. This report is an assessment of ISS induced charging from docked Orion vehicles employing negatively grounded, 130 volt class, UltraFlex (ATK Space Systems) solar arrays. To assess plasma electron current collection characteristics, Orion solar cell test coupons were constructed and subjected to plasma chamber current collection measurements. During these tests, coupon solar cells were biased between 0 and 120 V while immersed in a simulated LEO plasma. Tests were performed using several different simulated LEO plasma densities and temperatures. These data and associated theoretical scaling of plasma properties, were combined in a numerical model which was integrated into the Boeing Plasma Interaction Model. It was found that the solar array design for Orion will not affect the ISS FP by more than about 2 V during worst case charging conditions. This assessment also motivated a trade study to determine acceptable plasma electron current levels that can be collected by a single or combined fleet of ISS-docked VVs.