SEPTA® 24 Solar Array Drive Assembly

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SEPTA® 24 Solar Array Drive Assembly | Manualzz

SEPTA ® 24

Solar Array Drive Assembly

RUAG Space

| Schaffhauserstrasse 580 | CH-8052 Zurich | Switzerland

Phone +41 44 306 2211 | [email protected] | www.ruag.com/space

GENERAL DESCRIPTION

The SEPTA 24 Solar Array Drive Assembly (SADA) is designed to fulfill a large range of applications on satellites with a mass of approximately 5000 kg in LEO, MEO and GEO orbit that are used for scientific or telecommunications purposes by using a standard product to minimise costs on system level. The SADA will be full space qualified by end of 2012 and consists of an actuator, a slip ring assembly (composed of a collector for power and signal transfer) and potentiometers as well as a reference sensor (‘reset switch’) for position feedback. Cold redundancy can be achieved by equipping the SADA with two identical embedded drive potentiometer is an analogue 0 V to 12 V signal, delivering a continuous angular position of the SADA with a full measurement scale of 180°. The potentiometers have a total resistance of

6.25k

 10%. electronics for main and redundant operation. Within the qualification campaign of SEPTA 24 14100 cycles were performed during the life time test. The SADA has over 40 years of accumulated component flight heritage (C.F.H.).

The SADA is powered using a two phase hybrid stepper motor with redundant windings giving 57600 stable (un-powered) positions of the output shaft over one revolution.

The main functions of the SEPTA 24 are to sustain and rotate the

Solar Array Panel in both forward or reverse directions, as well as transfer power, signals and grounding from the Solar Array to the satellite. The SEPTA 24 has a very precise rotational resolution

(step size) of 0.00625° and a maximum speed of one rotation per

18 minutes. The position of the Solar Array is measured using two redundant potentiometers delivering an accuracy of 0.5°.

The collector consists of current transfer rings rated for 7.5 A or

10 A and 36 signal tracks at 0.5 A, two of which are used for

GND. Moulding of rings and contacts wires, together with wires and soldering points, within a charged space qualified epoxy gives a very high electrical insulation.

Position measurement is achieved using main and redundant potentiometers and a reset switch. The feedback of the

OPTIONS

The SEPTA 24 is available in a 12 or a 24 power track version

(7.5 A each) with and without SADE. The SEPTA 24-E/E incorporates fully space qualified electronics integrated at the

SEPTA 24 on two separate PCB’s. The SEPTA 24-E/S version is with an external SADE Box. Both SADE can be fed using 21 V to

40 V unregulated power bus. The SEPTA 24-M version without embedded electronics can be powered directly with a dual phase sinusoidal 21 V to 40 V input with a maximum current of 320 mA.

The following SEPTA 24 Models are available:

SEPTA

SEPTA

24-E/E x

SEPTA

24-E/S -

2 Septa 24 Solar Array Drive Assembly

DESIGN CHARACTERISTICS

Operational performance

Drive direction

Output speed range (nominal in orbit)

Maximum output speed (ground testing)

Stabile positions at input shaft (with motor unpowered)

1 output step between to stabile positions

1 full rotation range (at output shaft)

Life span

Revolutions performance

Qualification sequence

Delivered torque

SA holding torque with motor unpowered

SA holding torque with motor powered

SA driving torque (motor powered)

Limit for repeated peak torque

Limit for momentary peak torque

Power Transfer

Number of power transfers (forward & return lines)

Current

Voltage

Power transfer

Total line resistance at 20 °C (incl. external harness)

Total line resistance in the worst hot case (incl. external harness)

Insulation

Noise

Signal Transfer

Number of signal transfers (forward & return lines)

SA Ground lines

Current

Forward and reverse full rotation

0 to 20 revs per day

0.75 °/s

360 steps over a full revolution

0.00625°

57600 output steps

15 years in orbit

+ 5 year storage (2 years integrated on S/C)

250 on ground

5475 orbital full revs (1 revs / day)

1000 + 11000 = 12000 full revs up to 7 Nm

≥ 70 Nm up to 35 Nm

64 Nm (starting and stop)

76 Nm (exceptional peak torque)

12 or 24 transfers

7.5 A or 10 A up to 110 V (250 V resistant) up to 19.8 kW

29 mΩ (max.)

38 mΩ (max.)

≥ 10 MΩ at 500 V

≤ 5 mV

RMS

/A

34

2

0.5 A for signals (1.0 A with MIL derating)

1.0 A for SA ground

Total line resistance at 20 °C (incl. external harness)

Total line resistance in the worst hot case (incl. external harness)

Insulation

Noise

90 mΩ

105 mΩ

≥ 10 MΩ at 500 V

≤10 mV

RMS

/A

3 Septa 24 Solar Array Drive Assembly

Position Measurement

Potentiometer resistance

Potentiometer accuracy

Potentiometer linearity

Insulation

Noise (output smoothness)

Alignment between main and redundant unit

Reset Switch

Reset Switch low

Reset Switch high

Insulation

Alignment between position sensor and Reset Switch

Power Consumption (worst cold case)

Versions with SADE

Versions without SADE

P/F Interface Temperatures (design flight levels)

Ground Storage

In orbit non operational

Cold start-up limit

In orbit operational

SA Interface Temperatures (design flight levels)

Ground Storage

In orbit non operational

Cold start-up limit

In orbit operational

Environment conditions during operation

-E/S Radiation Total Dose (without external shielding)

-E/E Radiation Total Dose (without external shielding)

Combined loads (qualification levels)

Axial load (F y

)

Radial load (F xz

)

Bending moment (M xz

)

4 Septa 24 Solar Array Drive Assembly

6.25 k   20%

≤  2° over [0 ; 360°]

≤  0.25%

≥ 100 MΩ at 500 V

≤ 15 Ω

RMS

< 2°

1° <  < 178.5°

181.5° <  < 358.5°

≥ 100 MΩ at 500 V

< 2°

V

COILS

36 V

28 V

P motor

6.03 W

≈ 13 W

T min

+ 10 °C

- 30 °C

- 25 °C

- 20 °C

T

Ambient

+ 22 °C

P

SADE

3.26 W

T min

+ 10 °C

- 60 °C

- 30 °C

- 30 °C

T

Ambient

+ 22 °C

T

< 10 W

≈ 13 W max

+ 40 °C

+ 80 °C

+ 55 °C

T max

+ 40 °C

+ 100 °C

+ 100 °C

< 50 krad (worst case component level)

< 30 krad (worst case component level)

1 2 3 4 5

1250 N 200 N − 2225 N 2225 N

1200 N

120 Nm

500 N

500 Nm

200 N

630 Nm

4500 N −

Stiffnesses

Axial stiffness (K y

) 5.6 × 10 7 N/m

Shear stiffness (K xz

) 3.1 × 10 7 N/m

Torsion angular stiffness (K

θ y

Bending angular stiffness (K

θ xz

) 3.8 × 10 4 Nm/rad

Environment conditions during launch (qualification)

High level sine vibrations: sweep rate:

Frequency (Hz) MOUNTING PLANE // MOUNTING PLANE

5 to 21 11 mm 11 mm

21 to 100 20 g

2 oct / min

20 g

// MOUNTING PLANE MOUNTING PLANE

Random vibrations:

Global:

Freq. (Hz) Level

400-2000 -6 dB/oct

18.4 g rms

Frequency (Hz)

Freq. (Hz)

400-2000

Level

-6 dB/oct

Shock input levels Shock levels for each axes (X, Y, Z):

5 Septa 24 Solar Array Drive Assembly

SEPTA24-E/S - SEPERATED SADE

The Solar Array Drive Electronics allows to control and to command the stepper motors driving the solar array (typically one north and one south) of the Solar Array Drive Mechanics in micro-stepping. The SADE will use the shared facility provided by the standard equipment to interface with the satellite.

Remark that, in the current programme, the service modules will be developed for standard equipment having only one application module. In addition, notice that due to the simplicity of the data handling interface which consists of a ML16/DS16 protocol, the remote terminal will be located in the SADE module because consisting of a low level hybrid. This choice avoids developing an interface module having only one lowlevel hybrid. The SADE core takes in charge the management of:

- Functioning mode

- Speed profile

- Current Set Point

- Sensors management

Functioning modes

The main functioning modes are:

- Init mode

- Reference mode also called Acquisition mode

- Relative mode also called Driving mode

- Hold mode

- Cruise mode

- Boost mode

Radiation

- Total dose > 50 krad

- SEU Th > 40 Mev

- SEL Th > 100 Mev

SEPTA24-E/E - EMBEDDED SADE

The command interface of the SADE is

- to receive a frequency telecommand which defines the rotation speed of the motor and to drive the motor phases in order to rotate at the defined speed,

- to receive telecommand for a sense of rotation and to drive the motor in the correct direction,

- to receive the potentiometer signal and to digitise it with a

16 bit ADC converter,

- to take into account the reset switch signal,

- No ML16/DS16 or MIL1553 interface available on this emended SADE

Two identical and completely separated SADE will be provided per SADM, one for the main channel, the other for the redundant one.

Radiation

- Total dose > 30 krad

- SEU Th > 40 Mev

- SEL Th > 100 Mev

ESD

SEPTA

®

24-E/E and –E/S are ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulates on the human body and test equipment and can discharge without detection. Although the SADA features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.

DELIVERABLES

- - FM- or PFM-Units

- - Transport and Handling Jigs (temporary only)

- - EIDP (CD-ROM):

 Certificate of Conformity

 CIDL & ABCL

 Logbook

 Interface Control Document

 User’s Manual

 RfD’s / RfW’s

 NCR’s

 Minutes of Meetings

 Acceptance Test Plan

 Acceptance Test Report

FLIGHT MODEL ACCEPTANCE PROGRAM

The flight model acceptance program includes the following tests:

- Inspection and control

- Functional characteristics measurement

- Vibration tests (FM-level)

- Thermal vacuum cycling with performance tests

PACKAGING AND STORAGE

As delivered by RUAG SPACE the SEPTA 24 is mounted on a handling tool equipped with shock detectors. The SEPTA 24 must be kept in a clean room class 8 (100 000) environments and shall be protected from direct UV light. If moved out of a clean environment, it has to be double bagged and sealed in antistatic protective foil (ESD) under dry nitrogen.

6 Septa 24 Solar Array Drive Assembly

DIMENSIONS AND MECHANICAL INTERFACES FOR SEPTA 24

(24 Power Transfers)

Figure 1: SEPTA ® 24-E/E plan view (24 power tracks)

Figure 3: SEPTA ® 24-E/E Solar Panel Interface side view (24 power tracks)

7 Septa 24 Solar Array Drive Assembly

Figure 2: SEPTA 24 Model view (24 power tracks)

DIMENSIONS AND MECHANICAL INTERFACES FOR SEPTA 24

(12 Power Transfers)

Figure 4: SEPTA 24 plan view (12 power tracks)

Figure 6: SEPTA 24 Solar Panel Interface side view (12 power tracks)

Figure 5: SEPTA 24 Model view (12 power tracks)

8 Septa 24 Solar Array Drive Assembly

ELECTRICAL INTERFACES FOR SEPTA 24 with SADE

Figure 7: SEPTA ® 24-E/E SADE Block Diagram Figure 8: SEPTA ® 24-E/S power transfer and position sensor’s electrical interface

Information furnished by RUAG Space is believed to be accurate and reliable. However, no responsibility is assumed by RUAG Space for its use, or for any infringements of patents or other rights of third parties that may result from its use. No license is granted by implication or otherwise under any patent or patent rights of RUAG Space.

9 Septa 24 Solar Array Drive Assembly

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