1. CINEMA Orbit/Attitude? (looking down from top toward earth)
Spin Plane
Satellite flight path questions:
Flight Path
Flight Path Or
Earth
Spin Plane
Is antenna nadir pointing? Doesn’t look so since there are another pair on the opposite face of the satellite.
What is the satellite spin axis or plane relative to the flight path?
Basically, what is the satellite’s attitude and orbit w.r.t. flight path and earth?
Earth
Flight Path
Side View?
Or, rotate the body by 90 degree along the long axis?
Zenith View
(looking down from top toward earth)

2. CINEMA Propulsion System (mechanical)
Cold Gas Propulsion System (mechanical):
Propellant-
Propellant: 1,1,1,3,3,3-hexafluoropropane
Nominal Isp: 47s
Installed Isp: 40s
Nominal propellant pressure: C
System-
Number of units required per satellite: 3
Nominal unit size: 8cm x 8cm x1 cm (can be tailored)
Total mass per unit: 100 grams
Propellant mass per unit: 30 grams
Nominal thrust per nozzle: 10 mN
Minimum thrust impulse: 10µN-s
Satellite Performance-
Total mission delta-V: 3.6 m/s
P-Pod delta-V correction: 2m/s
Available mission delta-V: 1.6m/s
Required delta-V: m/s-per day (assumes 1km/day drift)
Expected delta-V: m/s-per day (assumes nozzle design and 3D drift w.r.t. each satellite)
Minimum Correction thrusting time: 3sec-per day
Expected mission endurance: 7 weeks
1. Most importantly, the stored energy in the propellant is not sufficient to significantly alter the orbital trajectory of the CINEMA satellite, thus providing an inherent fault tolerant design. If the propellant system fails, the CINEMA primary mission continues. The overall propellant pressure is very low at ~40 psia.
2. Each Cinema will need 3 units of 100grams each with propellant.
3. Temperature is nominally set at 25C. Deviations from this must be noted and accommodated.
4. Delta-V of 2m/s is used to correct initial P-Pod ejection error. This is a conservative estimate.
5. Maximum drift of 1km/day is assumed. Reported for satellites with similar ballistic coefficients at 600km orbits.
6. Expected delta-V incorporates drift, thruster design, and drift in 3 dimensions.
7. Minimum time to thrust each day to maintain distance is 3 seconds at maximum thrust.
8. Expected mission endurance of 7 weeks included conservative estimates.

3. CINEMA Propulsion System (electrical)
Cold Gas Propulsion System (electrical):
Electronic System-
Control processor: PIC16 or PIC18-class
Rate gyroscopes: ADXRS300 rate gyros x 3
Temperature sensor: Thermistor (in propellant tank)
Pressure sensor: MEMS (in propellant tank)
Power-
Electronic system voltage: 5V
Maximum electronic system power: 150mW (thrust operation)
Minimum electronic system power: 25mW (non-thrust operation)
Thruster valve voltage: 12V
Maximum thruster power: 1W (2 switched on, 5-10 seconds per day)
Heater power: depending on nominal satellite temperature, zero if ~20-25°C
Knowledge-
Position: need position relative to each CINEMA satellite, can use magnetometer? Radio signal strength?
Attitude: from CINEMA ADACS
Communication-
Protocol: RS-232 or I2C
Key issue may be the knowledge of the relative position of each CINEMA satellites. There are a potentially a few ways to determine this, either onboard or offboard, but must be feed into the propulsion system as part of the thrusting command decision.
The propulsion system can be slaved to the CINEMA CD&H, therefore providing full authority control to the satellite’s main processor instead of instruction based control via communication bus.
Communication bus can also be other protocols, requirement not rigid.
Valve power is only expected to be on for 5-10 seconds per day during correction thrusting.
Maximum electronic system power is associated with valve thrusting operations.
Minimum electronic system power (house keeping) can be further reduced down to sub-mW if absolutely required.
Maximum thruster power can be reduced by increasing thruster maneuver time. However, the total energy is required is roughly the same.
Onboard rate gyro is for thrust maneuver feedback and monitoring. Provides rotational null and indirectly monitors linear accelerations due to thrusting.

4. CINEMA Propulsion System Configuration
Thruster Nozzle Slit
Thruster Unit
Thruster unit only needs two thin slits (~1-2mm) for the nozzles. External devices can be mounted to it simply by accommodating these slits. Each unit is centrally mounted on each long face except on the side with the magnetometer boom aperture.
8cm x 8cm x 5cm
(can be tailored)
Thrust Lines (slight offset from line to CG)
The primary control degree of freedom is 1-direction along the spin plane and 2-opposing directions normal from the spin plane. Limited rotational control (with off-axis lateral motion for some cases) is available for the spin direction and spinning along the boom axis. CG
Delivery Date-
Optimistically: End of May 2010
Drop Dead: End of August 2010

5. Exposed and baked nozzle layer
Etched nozzle and valve layers with valves

6. Assembled Glass Stack

7. Electronics Board

8. Assembled Propulsion Module
300 g mass (dry)
Freon propellant
HFC 236fa
On-board gyro
Magnetometer
MEMS Gyro
Transceiver
The Aerospace Corporation

9. Vapor/Liquid Seperator Temperature Heater Coil Sensors
View from the Bottom
Vapor/Liquid
Seperator
Heater Coil
Temperature
Sensors

10. Air Table Testing

11. 90o Step Response