Project: QB50
UNIVERSITY OF OSLO
Author: T. A. Bekkeng
TITLE: MNLP User Manual
Document Number: QB50-MNLP-UiO-UM-0001 Iss. A
Date: 05h March 2015
Distribution:
MSSL
Dhiren Kataria
Alan Smith
Ben Taylor
Mark Hailey
Rahil Chaudery
Abdullah Khalil
Berend Winter
Peter Coker
Alan Spencer
Matthew Whillock
Gethyn Lewis
X
X
X
X
X
X
X
X
X
X
X
VKI
Jean Muylaert
Amandine Denis
Davide Masutti
Jan Thoemel
X
X
X
X
UiO
Tore Andre Bekkeng
Espen Trondsen
Joran Idar Moen
X
X
X
Page 1 of 15
Title: mNLP User Manual
Doc. No. QB50-mNLP-UiO-UM-0001 Iss. A
Page 2 of 15
CHANGE RECORD
ISSUE
DATE
A
05/03/2015
PAGES
CHANGED
COMMENTS
Initial release
CONTRIBUTORS
Name
Tore Andre Bekkeng
Espen Trondsen
Ben Taylor
Jonas Ringnes
Company
UiO
UiO
MSSL
UiO
Title: mNLP User Manual
Doc. No. QB50-mNLP-UiO-UM-0001 Iss. A
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CONTENTS
1
INTRODUCTION ...................................................................................................... 5
2
NORMATIVE AND INFORMATIVE DOCUMENTS .................................................. 6
2.1
2.2
NORMATIVE DOCUMENTS ...................................................................................... 6
INFORMATIVE DOCUMENTS .................................................................................... 6
3
ABBREVIATIONS .................................................................................................... 7
4
INSTRUMENT DESCRIPTION ................................................................................ 8
4.1.1
4.1.2
4.1.3
4.1.4
5
Functional Description .................................................................................. 8
Boom System ............................................................................................... 8
Deployment Mechanism ............................................................................... 9
Electron Emitter ............................................................................................ 9
DEFINITIONS AND WARNINGS ............................................................................. 9
5.1
5.2
5.3
6
ELECTRIC SHOCK .................................................................................................. 9
SHARP POINTS ................................................................................................... 10
ESD SENSITIVITY ................................................................................................ 10
WARNINGS AND CAUTIONS ............................................................................... 10
6.1
GENERAL WARNINGS AND CAUTIONS..................................................................... 10
7
INTERFACE DEFINITION...................................................................................... 11
8
INSTRUMENT ON-BOARD SOFTWARE AND OPERATION ............................... 11
9
DEPLOYMENT MECHANISM ............................................................................... 11
10
STAGE #2 MNLP ................................................................................................ 11
10.1 STAGE #2: DESCRIPTION ................................................................................ 11
10.2 SAFETY ........................................................................................................... 11
10.3 TRANSPORTATION AND HANDLING ..................................................................... 12
10.3.1 Unpacking the instrument ........................................................................ 12
10.3.2 Packing the instrument ............................................................................ 12
10.4 INSTRUMENT STORAGE .................................................................................... 12
10.5 TESTING ......................................................................................................... 12
10.6 CONNECTORS .................................................................................................. 12
10.7 REPORTING ..................................................................................................... 13
10.8 CUBESAT PRE-DELIVERY ACTIVITY ................................................................... 13
11
STAGE #3 MNLP ................................................................................................ 13
11.1
11.2
11.3
STAGE #3: DESCRIPTION ................................................................................ 13
SAFETY ........................................................................................................... 13
TRANSPORTATION AND HANDLING ..................................................................... 13
Title: mNLP User Manual
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11.3.1 Unpacking the instrument ........................................................................ 14
11.3.2 Packing the instrument ............................................................................ 14
11.4 INSTRUMENT STORAGE .................................................................................... 14
11.5 TESTING ......................................................................................................... 14
11.6 CONNECTORS .................................................................................................. 14
11.7 REPORTING ..................................................................................................... 14
11.8 CUBESAT POST-DELIVERY ACTIVITY ................................................................. 14
11.8.1 Stage #3 Mounting Procedure ................................................................. 14
11.8.2 Post mounting functional test .................................................................. 14
Title: mNLP User Manual
Doc. No. QB50-mNLP-UiO-UM-0001 Iss. A
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1 Introduction
This is the User Manual for the mNLP instrument.
It describes how to handle the mNLP payload at Stages #2 (with CubeSat Teams) and
#3 (with ISIS). Full interface definitions are given in the mNLP ICD [ND3].
The mNLP specific packet structures and formats produced by mNLP, and required by
the CubeSat OBC, are found in the mNLP ICD [ND3] to have a single source of the
information.
The bulk of this document is partitioned in to two major sections, describing the user
procedures for:

STAGE #2: Using a FLIGHT mNLP unit with a ~10Ω resistor as a replacement
for the electron emitter and flight booms in Section 10.

STAGE #3: Using the fully integrated FLIGHT mNLP instrument with filament
electron emitter and flight booms in Section 11.
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2
Normative and Informative documents
2.1 Normative Documents
ND1: CubeSat Design Specification Rev. 12
ND2: Test description (To be inserted when finalized)
ND3: QB50-MNLP-UiO-ID-0001 mNLP Science Unit Interface Control Document
ND4: QB50_Systems_Requirements_20131011_WOD_Annex– Issue 5
ND5: QB50-INMS-MSSL-PR-14001 STM Sensor Mounting Procedure
2.2 Informative Documents
None
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3
Abbreviations
ADC
ESD
FPGA
HV
INMS
LUT
mNLP
MSSL
PCB
RBF
STM
WOD
Analogue to Digital Converter
Electro-Static Discharge
Field Programmable Gate Array
High Voltage
Ion/Neutral Mass Spectrometer
Look Up Table
Multi-Needle Langmuir Probe
Mullard Space Science Laboratory
Printed Circuit Board
Remove Before Flight
Surface Thermal Monitor experiment
Whole Orbit Data
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4
Instrument Description
Figure 4-1- m-NLP CAD model with booms deployed
4.1.1 Functional Description
The multi-Needle Langmuir Probe instrument works by measuring the current collected
individually from four needle probes, placed in front of the satellite's shock front. The
collected current is converted to voltage, filtered, digitalized and then sent to the central
telemetry (TM) system. By using data from four fixed-bias Langmuir needle probes,
sampled at the same time, the plasma electron density can be derived with high time
resolution without the need to know the electron temperature and the spacecraft
potential. With the selected needle probe design and the estimated electron densities,
the instrument is to be capable of measuring currents ranging from 1 nA to 2 µA. The
m-NLP system consists of one data acquisition PCB, one PCB which acts as the
mounting plate for the miniaturized Langmuir Probes, one aluminium top plate and an
integrated electron emitter on top.
4.1.2 Boom System
The m-NLP boom system consists of four separate booms, mounted on a PCB placed
underneath the common top plate of the SU. Each of the booms has an individual
deployment mechanism, operated by the OBC. The deployment mechanisms are
placed on side panels of the CubeSat.
The boom system illustrated in Figure 4-1 is a representative view of the boom system.
Details on the deployment springs are not shown. The boom diameter is 2.2 mm, but
on the flight probes the outer 40 mm are thinner. The boom coating for the flight units
will be Aerodag G carbon paint. Care should be taken when handling the booms. Avoid
mechanical scratches in the paint.
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NOTE: The coating is very volatile with respect to alcohol based solvent. Therefore the
coated booms should be kept away from any cleaning procedure of the CubeSat that
involves alcohol or alcohol vapour.
4.1.3 Deployment Mechanism
The probes will have to be held down to the side panels at the far end of the satellite
structure for launch. The booms are sprung and are retained by a deployment
mechanism with a burn wire. The electrical interface to each deployment mechanism
will be two wires (deployment and deployment_return). The deployment_return signal
can either be routed as a dedicated current return signal, or the side panel ground
plane can be used. The OBC or the EPS system is commanded to deploy the boom, a
high current passes through the wire burning it out and releasing the sprung booms. A
logic signal is sent detecting the deployment of the booms, and transmitted as a part of
the SU_HK packet.
4.1.4 Electron Emitter
In the centre of the M-NLP Science Unit Boom System shown in Figure 4-1 there is
implemented a thermionic electron emitter to get rid of the collected electrons when the
payload is operating which drives the CubeSat floating potential to a too negative a
level when the CubeSat is in eclipse and photoelectron emission is absent. Results
from the ESTEC plasma chamber demonstrate emission currents higher than 10µA (>5
times higher than the maximum amount of collected current by positively biased M-NLP
probes.).
The dimensions of the emitter housing will be approximately ~17x22x19 mm (WxLxH).
Weight is estimated to ~12 grams.
5
5.1
Definitions and warnings
Electric shock
The highest voltage in the m-NLP SU is the most negative voltage used by the Electron
Emitter, which is ~40 V negative. This voltage is contained inside the SU, but the
CubeSat teams should anyway be cautious when handling the SU in a powered
condition.
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5.2
Sharp Points
The probe tips are to be regarded as a sharp point. The tip will likely bend if bumped
into by e.g. a hand, but is the tip accidentally hits an eye it can cause severe injury.
This calls for caution when being in close vicinity to the science unit where the probes
are in the deployed state.
5.3
ESD sensitivity
Parts of the instrument are sensitive to electro static discharge (ESD), this symbol may
appear on labels affixed to the instrument. ESD precautions must be followed or
damage to the instrument could occur.
6
Warnings and Cautions
6.1 General warnings and cautions
The following general safety precautions must be observed during all phases of
operation of this equipment.
Failure to comply with these precautions or with specific warnings elsewhere in this
manual violates safety standards of design, manufacture, and intended use of the
equipment.
Heed all warnings on the unit and in the operating instructions.






The mNLP should never be handled when powered with the bias inhibit plug
removed.
The mNLP MUST be connected to safety ground when being operated.
Follow precautions for static sensitive devices when handling the instrument.
A thorough check of the environment around the mNLP should be performed to
ensure no extraneous conductors are placed near the instrument probe tips.
Do not remove any protective covers.
The mNLP must be unpacked, handled and operated in clean conditions.
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7 Interface Definition
The mNLP is designed to be mounted in the ram direction at the end of a CubeSat
stack. Mounting holes are designed to be compatible with Pumpkin (with an adapter
plate) and ISIS structures via slotted holes. The mNLP has a single electrical/data
interface connection through a 25 way MDM connector.
For full Interface Definitions, see ND3.
8 Instrument On-Board Software and Operation
The mNLP uses an FPGA for all control of the digital and analogue circuits in the unit.
Simple commands are required from the CubeSat OBC to set operational modes via
scripting. CubeSat teams are responsible for correct implementation of script handling
by their OBC. For data interfaces and data packet formats, see ND3.
9
Deployment Mechanism
See ND3 (ICD) for detailed information.
10 Stage #2 mNLP
10.1 STAGE #2: Description
The STAGE #2 deliverable is an integrated mNLP unit representative of in size, mass,
and electrical interface of the flight mNLP instrument. It comprises:




5 AD590KF Surface Thermal Monitor for integration onto CubeSat. The AD590s
should be mounted and harnessed to the CubeSat as described in ND3. Note
should be taken of the location of each sensor as numbered. Mounting
instructions for the STM sensors are given in ND5.
A fully tested FM mNLP electronics. This has the digital control circuit that
interfaces to the CubeSat side via MDM interface connector – see ND3. The
PCBs contain all analog control and readout circuitry. An electron emitter is
installed on the upper PCB consisting of a series of electrodes and driving
circuit. A thermionic electron emitter filament is NOT included at Stage #2,
instead replaced with a dummy power resistor. A shield covers most of the
underside of the mNLP PCBs, however, some parts of the circuitry are still
exposed at the sides.
A set of four flight probes.
Full set of Flight mechanics including top plate and PCB fixings.
10.2 Safety
A thorough check of the environment around the payload should be performed prior to
switch on to ensure no extraneous conductors are placed near to the probes.
The mNLP should never be handled when powered with the probe bias plug removed.
At all times, the instrument should be connected to a safety ground, with the GND
signal connected to Earth.
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10.3 Transportation and Handling
General handling principals



The mNLP should be handled in a Cleanroom environment, ISO Class 8.
The mNLP is ESD sensitive and protection protocols shall be followed as
advised by IEC 61340-5-1.
Powder-free gloves must be worn when handling the instrument.
10.3.1 Unpacking the instrument
To be included as soon as all parts are manufactured, together with descriptive
pictures.
10.3.2 Packing the instrument
To be included as soon as all parts are manufactured, together with descriptive
pictures
10.4 Instrument Storage
The instrument should be kept at room temperature in low humidity environment at ISO
8 or better.
10.5 Testing
For details of tests to be conducted refer to ND2.
Precautions for handling ESD sensitive devices must be observed at all times and
precautions for high voltages should be observed whenever the instrument is powered.
All HK channels should be verified (voltages and temperatures etc.), external power
supply currents should be measured at power-on and during testing.
Once complete the data packets received should be verified to be in the correct format.
10.6 Connectors
The only external connector on the mNLP is the primary MDM 25 way connector as
detailed in ND3.
There can only be a maximum of 10 mate-demate cycles for this connector after
delivery; if more than this are anticipated then a saver must be used.
A Mate/De-mate log shall be kept of the main MDM connector and this will be supplied
with the unit.
The mNLP requires a remove before flight tag which must be kept on during ALL
testing except when specifically carrying out a test that turns on the probe bias circuit.
The removal of the RBF plug shall be recorded in the log book.
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10.7 Reporting
The mNLP shall be subject to outgoing and incoming inspections. An inspection report
sheet will be provided with the unit to be returned to UiO/MSSL. A log should be kept of
all activities of the mNLP to be returned to UiO/MSSL.
10.8 CubeSat Pre-Delivery Activity
Teams are required to keep the Stage #2 SU integrated in the CubeSat for delivery to
ISIS facilities for the QB50 flight. The Stage #3 electron emitter will be mated to the
Stage # SU by UiO personnel.
11 Stage #3 mNLP
11.1 STAGE #3: Description
The STAGE #3 deliverable is an integrated mNLP unit differing from the Stage #2 unit
by the following:
 Flight thermionic electron emitter filament replacing dummy power resistor
supplied at Stage #2
11.2 Safety
A thorough check of the environment around the payload should be performed prior to
switch on to ensure no extraneous conductors are placed near to the probes.
The mNLP should never be handled when powered with the probe bias plug removed.
At all times, the instrument should be connected to a safety ground, with the GND
signal connected to Earth.
No activation of the electron emitter should occur after the Stage #3 upgrade!
The bias inhibit RBF plug should remain fitted at all times prior to launch! Note
that during power-up of the instrument a bias voltage will be present on all four probes
during the power-up-sequence of the bias circuitry. This voltage will be disabled again
after about one second, and stay off as long as the RBF plug is fitted.
11.3 Transportation and Handling
General handling principals




The mNLP should be handled in a Cleanroom environment, ISO Class 8.
The mNLP is ESD sensitive and protection protocols shall be followed in advised
by IEC 61340-5-1.
Powder-free gloves must be worn when handling the instrument.
The flight probes are sensitive to contamination and should be handled with care
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11.3.1 Unpacking the instrument
To be included as soon as all parts are manufactured, together with descriptive
pictures.
11.3.2 Packing the instrument
To be included as soon as all parts are manufactured, together with descriptive
pictures.
11.4 Instrument Storage

The instrument should be kept at room temperature in a low humidity
environment at ISO 8 or better.
11.5 Testing
For details of tests to be conducted refer to ND2.
Precautions for handling ESD sensitive devices must be observed at all times and
precautions for high voltages should be observed whenever the instrument is powered.
All HK channels should be verified (voltages and temperatures etc.), external power
supply currents should be measured at power-on and during testing.
Once complete the data packets received should be verified to be in the correct format.
11.6 Connectors
N/A. SU will be kept mounted to the CubeSat at all time during this stage. No demating
is expected.
11.7 Reporting
The mNLP shall be subject to outgoing and incoming inspections. An inspection report
sheet will be provided with the unit to be returned to UiO/MSSL. A log should be kept of
all activities of the mNLP to be returned to UiO/MSSL.
11.8 CubeSat Post-Delivery Activity
Teams are required to keep the mNLP unit mated to their CubeSat during modification
from Stage #2 to Stage #3, including attachment of deployment wire as described in
§9. The electron emitter mounting activity shall take place at ISIS facilities and
conducted by UiO personnel.
11.8.1 Stage #3 Mounting Procedure
• Mount electron emitter with integrated connector. Fix with three screws.
11.8.2 Post mounting functional test
To be inserted. Description of a test script after 11.8.1.
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