Engineering, 01.12.2021 15:30 mckadams02
In the early 1990s, Lockheed Martin utilized a new thruster, the hydrazine arcjet for North-South station keeping (NSSK) on its
geostationary orbit satellites. The early R&D (through preflight qualification) on the hydrazine arcet was done at NASA Glenn
Research Center. The current production arcjet thrusters are manufactured by Aerojet Redmond. The Lockheed Martin series 7000
satellites use the Aerojet MR 509 hydrazine arcjet system (1.8 kW power level, Isp of 502 sec). The archet continues to evolve with the
latest Lockheed satellite bus, the A2100 satellites, which utilize the MR-510 arcjet system (2.2 kW, 582-sec nominal Isp thrusters) for
NSSK. Again, the archet thruster takes advantage of the higher satellite power available to substantially increase the performance
over catalytic hydrazine (Isp = 225 sec to Isp = 570 to 600 sec).
Answers: 1
Engineering, 03.07.2019 19:30
When using the ohmmeter function of a digital multimeter, the leads are placed in what position relative to the component being tested? a. parallel b. control c. series d. line
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Engineering, 04.07.2019 18:10
The mass flow rate of the fluid remains constant in all steady flow process. a)- true b)- false
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Engineering, 04.07.2019 18:10
Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?
Answers: 1
Engineering, 04.07.2019 18:10
Which one from below is not one of the reasons of planning failures? (clo3) a)-planner is careless. b-planner spend less time in the field but more time on the desk c)-planner is not qualified d)-planner does not have sufficient time to properly plan
Answers: 3
In the early 1990s, Lockheed Martin utilized a new thruster, the hydrazine arcjet for North-South st...
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