AVSS Project. ENAE483 Fall 2012

Transcription

1 AVSS Project ENAE483 Fall 2012 Team D9: Jason Burr Vera Klimchenko Grant McLaughlin Johnathan Pino

2 Link Budget Analysis

3 Maximum Earth-Moon Transmission Distance R M D R M R e Moon 406,700 km Earth

4 Ku Band Direct to Earth Ku Band frequency: 1.2x10 10 Hz Slant Range: ~406,701 km apogee Ground station communication receiver diameter of 20m (compare to 70m DSN dishes) Maximum power of 20 watts Design to at least a 3dB link margin Receiver noise temperature on Earth: 300k Data rate of 4mbps sufficiently high for telemetry, voice, and media (such as video and images) A.5m transmitter using ~6 watts provides link margin of 3.23 db At this power level and data rate, the signal:noise ratio available (7.91e7) is about 150% larger than the required ratio (3.76e7)

5 Ku Band Direct to Earth

6 S Band Direct to Earth S Band frequency: 2.5x10 9 Hz Slant Range: ~406,701 km apogee Ground station communication receiver diameter of 20m Maximum power of 50 watts Design to at least a 3dB link margin Receiver noise temperature on Earth: 300k A.5m transmitter using ~29 watts provides a link margin of 3.11 db Long range and relatively low frequency of S band prohibits data rates above 1mbps using the.5m receiver (still enough for telemetry and voice) At this power level and data rate, the signal:noise ratio available (9.4e6) is about 100% larger than the required ratio (1.92e7 )

7 S Band Direct to Earth

8 Ka Band to L2 Relay Satellite Ka Band frequency: 3.2x10 10 Hz Slant Range: ~60,000 km Relay satellite receiver diameter of 1m Maximum power of 20 watts Design to at least a 3dB link margin Receiver noise temperature on in orbit: 100k A.5m transmitter using ~3 watts provides a link margin of 3.15 db Data rate of 4mbps sufficient for telemetry, voice, and video At this power level and data rate, the signal:noise ratio available (3.76e7) is about 100% larger than the required ratio (7.76e7)

9 Ka Band to L2 Relay Satellite

10 Ku Band L2 Relay Satellite to Earth Ku Band frequency 1.2x10 10 Hz Slant Range ~466,700 km (apogee) Relay satellite transmitter diameter of 1m Maximum power of 20 watts Design to at least a 3dB link margin Receiver noise temperature on Earth: 300k A 1m diameter transmitter using ~3 watts provides a link margin of 4.01 db Data rate of 4mbps sufficient for telemetry, voice, and video At this power level and data rate, the signal:noise ratio available (3.76e7) is about 150% larger than the required ratio (9.62e7)

11 Ku Band L2 Relay Satellite to Earth

12 UHF OMNI to EVA Suits UHF Band frequency: 9.0x10 8 Hz Maximum EVA distance: 10km o Max distance NASA designed for an Apollo rover breakdown Higher BER (voice only) Design to at least a 5dB link margin o Want more safety in EVA communications Receiver noise temperature on the moon: 300K Data rate of 50 Mbps more than sufficient for telemetry, voice, and video (worst case loading of wide-band payload) An omni transmitter using ~6 watts provides a link margin of 4.88 db, even at 50 Mbps! At this power level and data rate, the signal:noise ratio available (1.45e09) is about 1500% larger than the required ratio (9.62e7)!

13 UHF OMNI to EVA Suits

14 Power Availability PPT project (Team B9) 150 Watts continuous power (including eclipse) allotted for avionics and communications Higher power possible during non-eclipse periods by drawing from panels and batteries Total power required of 47 watts well within design limits Link Ku Band Direct to Earth 6 S Band Direct to Earth 29 Ku Band to L2 Relay 3 Ka Band to L2 Relay 3 UHF OMNI to EVA Suits 6 Total 47 Power (watts)

15 Sensors

16 Sensors Sensor groups: Crew Cabin: Atmosphere Crew Cabin: Other Actuators and Interfaces Propulsion Power & Communications Description of sensors: Parameter/Status Type of sensor Number of sensors Frequency of data sampling o low (seconds) o medium (<1s) o high (continuous) Criticality of sensor (in ascending order): o mission critical o flight critical o crew critical Redundancy o other sensors with redundant data

17 Sensors: Crew Cabin Parameter/Status Type Number Frequency Criticality Redundancy Cabin Atmosphere Pressure pressure transducer 1 medium crew O2, N2, CO2, T O2 in Atmosphere flow rate 1 medium crew P, N2, CO2, T, tanks N2 in Atmosphere flow rate 1 medium crew P, O2, CO2, T, tanks CO2 in Atmosphere CO2 detector 1 medium crew P, O2, N2, T Cabin Temperature temperature transducer 1 medium crew P, O2, N2, CO2 Level of O2 (tank) flow rate 1 low crew O2 tank P and T Level of N2 (tank) flow rate 1 low crew N2 tank P and T Pressure of O2 (tank) pressure transducer 1 high crew O2 tank level and T Pressure of N2 (tank) pressure transducer 1 high crew N2 tank level and T Temperature of O2 (tank) temperature transducer 1 high crew O2 tank level and P Temperature of N2 (tank) temperature transducer 1 high crew N2 tank level and P

18 Sensors: Crew Cabin Continued Parameter/Status Type Number Frequency Criticality Redundancy Humidity humidity sensor 1 low crew - Waste Management pressure transducer 1 low crew - Particle Contamination particle spectrometer 1 low crew - Water N2 pressure transducer, flow rate 2 high crew with same Outside Temperature temperature transducer 1 medium mission - Fire smoke detectors 1 high crew - Radiation Levels dosimeter/particle spectrometer 1 low crew -

19 Sensors: Actuators & Interfaces Parameter/Status Type Number Frequency Criticality Redundancy Door Lock limit switch 1 high crew - Docking Lock limit switch 2 high mission - Solar Array Deployment and Orientation rotary binary encoder 2 high mission - Radiator Deployment and Orientation rotary binary encoder 2 high crew - Seatbelts limit switch 3 high crew - Landing Gear: Deployment sight lines, rotary binary encoder 4 high mission - Landing Gear: Lock limit switch 4 high mission - Landing Gear: Touchdown limit switch 4 high mission with same Structural Vibration strain gauges many high crew,flight with same

20 Sensors: Propulsion Quantity/Status Type Number Frequency Criticality Redundancy Chamber Pressure pressure transducer 18 high crew, flight chamber T Chamber Temperature temperature transducer 18 high crew, flight chamber P N2 Valve limit switch 1 high flight - H2N2 Valve limit switch 1 high flight - N2 Levels flow rate 1 high flight N2P tank P and T H2N2 Levels flow rate 1 high flight H2N2 tank P and T N2 Tank Pressure pressure transducer 1 high crew N2 tank level and T N2H2 Tank Pressure pressure transducer 1 high crew H2N2 tank level and T N2 Tank Temperature transducer 1 high crew N2 tank level and P N2H2 Tank Temperature transducer 1 high crew H2N2 tank level and P

21 Sensors: GNC Quantity/Status Type Number Frequency Criticality Redundancy Acceleration, Velocity accelerometer many high flight with same Attitude and Angular Rate gyros 4 high flight extra gyro Orientation star tracker, CSS, sun sensor 3 low flight with similar Proximity proximity sensors many high mission with same Docking LIDAR 1 high mission - Thruster Orientation rotary binary encoder 18 low flight -

22 Sensors: Power & Communication Quantity/Status Type Number Frequency Criticality Redundancy Battery Charge voltmeter 3 low flight with same Current ammeter many high flight voltage, power Voltage voltmeter many high flight current, power Electronics Temperature temperature transistor many high flight with same Power Usage ammeter, voltmeter many high flight voltage, current Clock and Event Timers crystal oscillator many high mission with same Dish Orientation rotary binary encoder 1 low mission - Display of Information monitors many high mission, crew with same

23 Design, Build, Test, Evaluate Projects

24 DBTE Projects Possible Design/Build/Test/Evaluate (DBTE) projects for ENAE 484 next term Project Concept Research Objective Required Mockup/Test Apparatus Concept of Test Operations The top three concepts are ranked in priority order based on: Importance and feasibility Criticality to the overall goal of lunar exploration architecture

25 DBTE Projects: Concept 1 Project Concept: Cargo and construction of lunar base in 1/6g Research Objective: How well can astronauts in EVA suits construct and/or assemble lunar base modules o These structures will have to be more rigid and have stronger connections than on existing structures, ISS for example, because they will be under weight loads Required Mockup/Test Apparatus: Simulation of 1/6g (NBT) and mock modules with connecting devices and tools

26 DBTE Projects: Concept 1 Continued Concept of Test Operations: o Time a test subject performing basic construction operations such as connecting two modules o How much weight can they lift and accurately guide into place? o Can they use tools in different orientations? Dexterity? o Can you access all material easily from cargo bays o How long can you exert yourself? How long do you need to rest after full exertion? How many hours of construction can you reasonably expect during a mission based on work/rest ratio? What kind of structure can be built in this time?

27 DBTE Projects: Concept 1 Continued

28 DBTE Projects: Concept 2 Project Concept: Capsule layout for ingress/egress and EVA rehearsal Research Objective: To simulate EVA procedures to determine conflicts and bottlenecks related to capsule interior layout. o What is the procedure for getting into the suits in a small and confined space? o Can you open the door from the ladder? o Are there any hazards to the astronaut and space suit as they descend/ascend the ladder? o How long does the process take? o Is the desired capsule layout compatible for non-eva activities and neutral body postion?

29 DBTE Projects: Concept 2 Continued Required Mockup/Test Apparatus: Mockup of interior volume with obstructions and hatch. Crew capsule will be elevated to simulate descent and ascent on ladder. Concept of Test Operations: Perform denitrogenation Put on suits Depressurize cabin Open hatch Descend ladder Ascend ladder Close hatch Pressurize cabin Remove Suits

30 DBTE Projects: Concept 2 Continued

31 DBTE Projects: Concept 3 Project Concept: Sight line analysis for lunar landing and docking Research Objective: Determine if the cockpit design provides a wide enough field of view for a pilot to perform successful docking and landing operations Required Mockup/Test Apparatus: Mock cockpit with seat, windows, and mock obstructions that would be present, as well as a mock objective such as the lunar surface or docking target vehicle

32 DBTE Projects: Concept 3 Continued Concept of Test Operations: o Construct a mock cockpit with equivalent field of view o Simulate docking scenario Can the pilot see the entire (or enough of) the target spacecraft, its docking apparatus, and the docking apparatus on his or her vehicle for the entire approach? o Simulate landing scenario Can the pilot see the landing site, landing gear, and any obstructions clearly enough and for long enough to accurately land the spacecraft on the desired site

33 DBTE Projects: Concept 3 Continued

34 DBTE Projects: Concept 4 Project Concept: Human/robot interactions Research Objective: To determine the effectiveness of robot designs and the impact of the robot on mission objects and crew tasks. How aware is the astronaut of the robot? How long does the astronaut have to wait for the robot to respond to requests? Does the robot impact visibility?

35 DBTE Projects: Concept 5 Coninued Required Mockup/Test Apparatus: o A scale model of the capsule, propulsion module and landing gear with an accurate center of gravity o A variety of simulated moon surfaces Concept of Test Operations: o For each moon surface, test landing on 1, 2, 3, or 4 legs o For each moon surface, test landing at different velocities o For each moon surface, test landing assuming a propulsion system malfunction

36 DBTE Projects: Concept 6 Project Concept: Outreach surveys Research Objective: What would make people excited about going to the moon? Ask them this: if you heard in the news tomorrow that astronauts did "x" on the moon, what would be the thing that gets you the most excited about the moon?

37 DBTE Projects: Concept 6 Continued Required Mockup/Test Apparatus: o Surveys Concept of Test Operations: o Create surveys (physical, online?) o Determine how to distribute o Determine where to distribute o Collect data o Evaluate responses

38 DBTE Projects The top three concepts are ranked in priority order based on: Importance and feasibility Criticality to the overall goal of lunar exploration architecture 1.) Lunar Construction and Cargo Containers 2.) Capsule Layout and Ingress/Egress 3.) Scaled Landing Tests

39 Sources "NASA Quest - Space Team Online." NASA Quest - Space Team Online. NASA, n.d. Web. 14 Dec "Small Satellites Earth Observation - Surrey Satellite Technology Ltd (SSTL)." Small Satellites â Earth Observation. N.p., n.d. Web. 14 Dec "UHF - RF Transmitter ICs Semtech." UHF - RF Transmitter ICs Semtech. N.p., n.d. Web. 14 Dec "UHF - RF Transmitter ICs Semtech." UHF - RF Transmitter ICs Semtech. N.p., n.d. Web. 14 Dec