University of Leicester
PLUME
Ref: PLM-PAY-SystemBudget-025-4
Date: 14/10/09
Payload system mass, power, size and cost estimates
P. Peterson
Date
Updated Reference Number
change
?
17/11/2008
14/10/2009
PLM-PAY-SystemBudget-025-2
PLM-PAY-SystemBudget-025-3
PLM-PAY-SystemBudget-025-4
2nd version issued
3rd version issued
Updated document to
reflect final design choices.
The payload can be divided into several smaller systems:






The physical MCP detector bodies and plates
The High voltage (HV) supply, resistive divider, digital analog converter (DAC) and
I/V monitoring circuits
The signal processing electronics and analog buffer circuit
The auxiliary power supply needed to provide a ±5V dual input to the signal and HV
subsystems.
The Camera and its interfaces
The switching interface, needed to multiplex the outputs from the buffer and monitors
onto the single ADC on the MCU.
The satellite is mounting two MCP detectors, so we will need two sets of all the elements
listed below save the camera.
Where the power supply for an element is provided through the HV transformer or dual 5V
auxiliary power supply, their power requirements are included in the requirements for the
supplies and do not individually contribute to the total power requirement.
MCP body (x2 Required)
Mass
15g
Power
66mW provided by HV supply
Size
4.5x38x38mm, externally mounted
Cost
None
Notes: The MCP bodies and plates are being generously supplied by Photonis at
no cost.
Page 1 of 4
University of Leicester
PLUME
Ref: PLM-PAY-SystemBudget-025-4
Date: 14/10/09
HV supply, resistive divider, DAC and I/V monitor (x2 Required)
Mass
19.25g
Power
Idle 2mW, Active 257mW supplied by auxiliary supply and 5V bus.
Size
30x30mm board, 20mm clearance on one side.
Cost
$125 per HV supply + one-off $25 handling charge
Notes: The tiny EMCO Q12N-5 high voltage supply is very inefficient, drawing
50mA even at zero load. The DAC is a based on a summing amp, and the HV
monitor will need only a couple of op-amps tied across the high voltage resistive
divider. The mass estimate includes the aluminum conductor from power supply
to frame.
Signal processing, analog buffer (x2 Required)
Mass
16g
Power
71mW supplied by auxiliary supply
Size
30x30mm board, 15mm clearance.
Cost
$950 per chain, $60 each delivery
Notes: The analog buffer must be manufactured in-house and some exchange of
components may be necessary. The AmpTek components are expensive, but
resilient to power supply fluctuations, accurate and (importantly) radiation
hardened.
Auxiliary power supply (x2 Required)
Mass
8g
Power
Draws at most 342mW supplied by 5V satellite bus
Size
20x20mm board, 15mm clearance.
Cost
£2.49 each +£7.50 shipping. (Rutroniks)
Notes: The auxiliary power supply provides a dual ±5V supply for some of the HV
monitor circuits and the signal processing electronics. The Recom RM series
unregulated supply is inexpensive, produces fairly quiet power and is efficient
for its type.
Page 2 of 4
University of Leicester
PLUME
Ref: PLM-PAY-SystemBudget-025-4
Date: 14/10/09
Camera
Mass
12.5g + shield
Power
Active 40mW, Idle 1mW supplied by 3.3V satellite bus.
Size
41x28mm footprint. See mechanical interface document. 21mm long,
from the lens to the hilt of the connectors.
Cost
Provided free by OmniVision
Notes: A camera has been generously supplied by Omnivision, including a lens.
It is designed for use in a webcam, and will need an aluminum radiation shield of
currently unknown design. The camera is mounted on a separate PCB and its
surface area is not included in the size total.
Circuit board
Mass
87g
Power
None
Size
90x90mm, top slot only
Cost
£200
Notes: This board mounts nearly all the payload systems in addition to the
camera and ADCS board. Mass estimate includes on-board connectors but not
cables or connectors to the MCP bodies.
Page 3 of 4
University of Leicester
PLUME
Ref: PLM-PAY-SystemBudget-025-4
Date: 14/10/09
- Total mass estimate 216g , +50% contingency: 324g
- Total board size estimate: 4800mm2 +25% contingency: 6000mm2
Camera board not included.
- Total power consumption estimate:
Camera:
Active: 40mW
Idle: 30uW.
One MCP detector:
Active: 518mW +25% contingency: 648mW
HV off: 261.5mW +25% contingency: 326mW
Idle: 2mW
Both MCP detectors: Active: 856mW +25% contingency: 1070mW
HV off: 342mW +25% contingency: 427.5mW
Idle: 2mW
The MCP’s idle rating involves turning off both the signal processing chain and the
HV supply. The signal chain draws enough power that leaving it on all the time makes no
sense.
- Cost estimates:
3x Signal processing chain ($950x3) +$60 shipping
3x HV supply ($125x2) +$25 shipping
2x Auxilliary supply (£2.49x2) +£7.50 shipping
2x Circuit board (one will be a lab model costing half as much) (£300)
1x Camera ($167.65)
2x MCP detector body ($0)
Total + $200 contingency: $3720 + £312.50
Page 4 of 4