KPL/IK
RPWI Instrument Kernel
===============================================================================
This instrument kernel (I-kernel) contains the Radio and Plasma Wave
Instrument (RPWI) sensors' parameters and structure locations definitions.
It also provides an example to obtain the position of these strucutres.
Version and Date
-------------------------------------------------------------------------------
Version 0.3 -- December 8, 2022 -- Marc Costa Sitja, ESAC/ESA
Added structures definitions, RPWI views, and a code example.
Version 0.2 -- June 04, 2016 -- Marc Costa Sitja, ESAC/ESA
Claudio Jose Munoz Crego, ESAC/ESA
Updated all NAIF ID codes from -907* to -28* since the JUICE
spacecraft NAIF ID has been updated from -907 to -28.
Initial Release. Pending review by the RPWI instrument team.
Version 0.1 -- May 12, 2016 -- Jorge Diaz del Rio, ODC Space
Added instrument description.
Version 0.0 -- April 26, 2016 -- Jorge Diaz del Rio, ODC Space
Initial Release. Pending review by the RPWI instrument and
JUICE Science Operations Working Group teams.
References
-------------------------------------------------------------------------------
1. ``Kernel Pool Required Reading''
2. ``C-kernel Required Reading''
3. JUICE Frames Definition Kernel (FK), latest version.
4. ``JUICE - Jupiter Icy Moons Explorer. Exploring the emergence of
habitable worlds around gas giants. Definition Study report,''
ESA/SRE(2014)1, September 2014 (JUICE Red book v1.0)
5. ``JUICE - JUpiter Icy Moons Explorer RPWI (Radio & Plasma Waves
Investigation) Experiment Interface Document - Part B,''
JUICE-IRF-RPWI-EID-003, Issue 2.1, 16 June 2013
6. JUICE Mechanical Drawings and CAD model for external structures,
July 2022.
Contact Information
-------------------------------------------------------------------------------
If you have any questions regarding this file contact the
ESA SPICE Service (ESS) at ESAC:
Alfredo Escalante Lopez
(+34) 91-8131-429
spice@sciops.esa.int
or the JUICE Science Operations Center at ESAC:
Marc Costa Sitja
(+34) 646-746-711
Marc.Costa@ext.esa.int
Implementation Notes
-------------------------------------------------------------------------------
This SPICE I-kernel defines not values for the the ``kernel pool'', it
was created with, and can be updated with a text editor or word processor.
Instrument Description and Overview
-------------------------------------------------------------------------------
The Radio & Plasma Wave Investigation (RPWI) provides an set of
electromagnetic fields and cold plasma instrumentation, where several
different types of sensors will sample the thermal plasma, DC electric
fields, electric and magnetic signals from radio, plasma waves and
micrometeorite impacts, as well as monitoring the spacecraft potential and
integrated EUV flux (see [4] and [5]).
RPWI is a versatile instrument for in situ investigations of the highly
dynamic and, in many respects, very different space plasma environments,
which will be encountered by the JUICE spacecraft around Jupiter's icy moons
and in Jupiter's magnetosphere. To this end, RPWI makes use of several
different sensors and receivers. Altogether, the instrument uses 10 sensors
and 3 receivers, which cover a wide frequency range, from DC up to 45 MHz.
There are 4 Langmuir probes (LP-PWI) for plasma and electric field
measurements, a search coil magnetometer (SCM) with 3 coils for magnetic
fields measurement, and 3 radio antennas (RWI). Thus, the RPWI sensors
provide complete measurements of the electric and magnetic field vectors.
This makes it possible to unambigously measure true physical observables,
such as the energy flux (Poynting vector) and the wave polarization. The
radio antennas provide remote sensing capabilities to RPWI, including the
possibility to perform polarimetry and direction finding of coherent
(non-thermal) radio emissions.
The functional description of the RPWI system is most conveniently
described in terms of its three different experiments, GANDALF, MIME, and
JENRAGE (see [5] for further details):
- GANDALF (GANymede plasma Density And Low-Frequency wave instrument):
- LP-PWI (Langmuir Probe - Plasma Wave Instrument)
- SCM (SearchCoil Magnetometer)
- LP receiver
- LF receiver
- MIME (Mutual IMpedance Experiment)
- LP-PWI
- RWI (Radio Wave Instrument)
- LP receiver
- HF receiver
- JENRAGE (Jupiter ENvironment Radio Astronomy and Ganymede Exploration)
- RWI antenna
- HF receiver
GANDALF makes use of four spherical Langmuir probes (LP-PWI), 10 cm in
diameter, mounted on separate 3 metre long deployable booms. The probes can
be operated in two different modes:
- current sampling mode (used as Langmuir probes) or;
- voltage sampling mode (used as electric field probes).
The LP and LF receivers are the main receivers for the LP-PWI probes. The
Search Coil Magnetometer (SCM), which will be mounted on the J-MAG boom, is
connected directly to the LF receiver. In addition, the probes serve the
MIME experiment, which use them for transmission and reception for
frequencies up to 1.47 MHz. For higher frequencies (up to 3 MHz), the
probes are used for tramsission and the RWI antenna for reception. The
MIME drivers are then synchronized to the frequency of the HF receiver.
The functionality of the MIME subsystem is that of a laboratory network
analyzer, which is an advanced Ohm-meter used to measure the frequency
dependent complex impedance of an unknown device or medium. The medium,
in this case the space plasma, is stimulated by a sinusoidal signal, which
is and transmitted by one pair of Langmuir probes and received by the other
pair. During normal operations in the HF range (above 1.47 MHz up to 45
MHz) the RWI antennas will be used for reception.
JENRAGE makes use of three 2.5 meter long mutually perpendicular radio
antennas (RWI) to measure three components of the high-frequency electric
field in the 0.08 - 45 MHz range.
The main characteristics of RPWI sensors are provided in the following
table:
LP-PWI:
--------------------------------------------------------------------
PARAMETER VALUE
------------------------------ -----------------------------------
Frequency band DC- 1.47 MHz
Sensitivity (DC E-field) 1 mV/m (1)
Sensitivity (AC E-field) 10 nV/m/Hz-1/2 @ 1MHz
Density range (Electrons) 10-4 to 10+5
Density range (Ions) 1 to 10+5
Temperature range (Electron) 0.02 - 30 eV
Temperature range (Ion) 0.02 - 20 eV
Probe bias voltage -100 to +100 V
Probe bias current -100 to +100 nA
Input impedance >10+12 (E-field); <100 (Density)
--------------------------------------------------------------------
(1) Error @ DC: <7 mV/m (in Jupiter's magnetosphere)
<1 mV/m near icy moons
LP-Receiver:
--------------------------------------------------------------------
PARAMETER VALUE
------------------------------ -----------------------------------
Frequency band DC-1.47 MHz (E-field)
DC-10 kHz (Density)
Max E-field amplitude +/-0.5 V/m
Dynamic range >100 dB (E-field)
>120 dB (Density)
--------------------------------------------------------------------
LF-Receiver:
--------------------------------------------------------------------
PARAMETER VALUE
------------------------------ -----------------------------------
Frequency band 0.1 - 20000 Hz
Maximum AC M-field amplitude 5 nT
Maximum E-field amplitude 1 V/m
Dynamic range >70 dB
Input impedance >5000 Ohm
--------------------------------------------------------------------
RWI:
--------------------------------------------------------------------
PARAMETER VALUE
------------------------------ -----------------------------------
Frequency band 0.08 - 45 MHz
Sensitivity 2 to 3 nV/Hz1/2 @ 10MHz
10 nV/Hz1/2 @ 10MHz (2)
Gain 20 dB
Cross-talk <-40 dB
2nd harmonic distortion <-40 dB
Input swing 0.12 V (Peak-to-peak)
Output swing 1.2 V (Peak-to-peak)
Output impedance 50 Ohm
Ripple 20 mV (3)
--------------------------------------------------------------------
(2) Including antenna gain.
(3) Peak-to-peak, within the working frequency band.
SCM:
--------------------------------------------------------------------
PARAMETER VALUE
------------------------------ -----------------------------------
Frequency band 0.1 - 20000 Hz
Sensitivity 4 fT.Hz-1/2 @ 4kHz
Scale factor 100 mV/nT
Output swing 6 V (4)
Output impedance >1 kOhm
Ripple 0.1mV (5)
--------------------------------------------------------------------
(4) 50nT peak-to-peak @ Full Scale.
(5) Peak-to-peak within the working frequency band.
MIME:
--------------------------------------------------------------------
PARAMETER VALUE
------------------------------ -----------------------------------
Frequency band (LP/LP mode) 1-1470 kHz
Frequency band (LP/RWI mode) 80-3000 kHz
Density range 0.01-10000 particles/cm3
Temperature range 0.01-100 eV
Density resolution <5%
Temperature resolution <15%
Data Acquisition 1 spectra/min (Survey mode)
8 spectra/min (Burst mode)
Emission signal 2 V (6)
Output impedance ~10+6 Ohm
--------------------------------------------------------------------
(6) Peak-to-peak @ Full Scale; Depending on the distance between
transmission probes and reception probes
Mounting Alignment
-------------------------------------------------------------------------------
Refer to the latest version of the JUICE Frames Definition Kernel (FK) [3]
for the RPWI reference frame definitions and mounting alignment
information.
RPWI structure location specification
-------------------------------------------------------------------------------
The following table lists the name, center, and position for each of the
structures/sensors available for RPWI, providing the reference frame used
for their specification and the center to which they are referenced.
Structure/Sensor Center X,mm Y,mm Z,mm
------------------ --------------- ------- ------- -------
JUICE_RPWI_RWI JUICE_MAG_BOOM 8573.3 0.0 0.0 (1)
JUICE_RPWI_RWI_EX JUICE_RPWI_RWI -22.0 -15.2 186.2 (1)
JUICE_RPWI_RWI_EX_P JUICE_RPWI_RWI 1091.7 334.3 653.9 (1)
JUICE_RPWI_RWI_EX_M JUICE_RPWI_RWI -1135.7 -364.7 -281.6 (1)
JUICE_RPWI_RWI_EY JUICE_RPWI_RWI 67.2 31.2 145.6 (1)
JUICE_RPWI_RWI_EY_P JUICE_RPWI_RWI -402.9 1165.4 417.2 (1)
JUICE_RPWI_RWI_EY_M JUICE_RPWI_RWI 537.2 -1103.1 -126.0 (1)
JUICE_RPWI_RWI_EZ JUICE_RPWI_RWI -29.2 79.3 133.5 (1)
JUICE_RPWI_RWI_EZ_P JUICE_RPWI_RWI -375.6 -336.2 1268.7 (1)
JUICE_RPWI_RWI_EZ_M JUICE_RPWI_RWI 317.2 494.7 -1001.8 (1)
JUICE_RPWI_SCM JUICE_MAG_BOOM 8201.3 0.0 0.0 (1)
JUICE_RPWI_SCM_EX JUICE_RPWI_SCM 14.6 72.6 128.3 (1)
JUICE_RPWI_SCM_EX_P JUICE_RPWI_SCM 14.6 -29.0 119.0 (1)
JUICE_RPWI_SCM_EX_M JUICE_RPWI_SCM 14.6 174.2 137.7 (1)
JUICE_RPWI_SCM_EY JUICE_RPWI_SCM -15.4 118.1 90.6 (1)
JUICE_RPWI_SCM_EY_P JUICE_RPWI_SCM -15.4 109.2 192.2 (1)
JUICE_RPWI_SCM_EY_M JUICE_RPWI_SCM -15.4 127.0 -11.0 (1)
JUICE_RPWI_SCM_EZ JUICE_RPWI_SCM -0.4 82.5 94.4 (1)
JUICE_RPWI_SCM_EZ_P JUICE_RPWI_SCM -102.4 82.5 94.4 (1)
JUICE_RPWI_SCM_EZ_M JUICE_RPWI_SCM 101.6 82.5 94.4 (1)
JUICE_RPWI_LPB1 JUICE_SPACECRAFT 1383.8 1134.2 2280.9
JUICE_RPWI_LP1 JUICE_RPWI_LPB1 2950.0 14.3 0.0 (2)
JUICE_RPWI_LPB2 JUICE_SPACECRAFT 1455.0 -1162.3 3207.3
JUICE_RPWI_LP2 JUICE_RPWI_LPB2 2950.0 14.3 0.0 (2)
JUICE_RPWI_LPB3 JUICE_SPACECRAFT 1455.0 -1162.3 246.8
JUICE_RPWI_LP3 JUICE_RPWI_LPB3 2950.0 14.3 0.0 (2)
JUICE_RPWI_LPB4 JUICE_SPACECRAFT -1378.5 1143.4 2335.7
JUICE_RPWI_LP4 JUICE_RPWI_LPB4 2950.0 14.3 0.0 (2)
(1) The value provided in this table is the one that corresponds
with the fully deployed boom (note that the boom is folded in
three pieces when stowed). See [6] for further details.
(2) As stated in [6], the Langmuir Probe booms are 3 meters in
length, including the Langmuir probes, which are 10 centimeters
in diameter. The center of the Langmuir probe is considered the
center of mass of the sensor. The value provided in this table
is the one for the fully deployed boom (note that the boom is
folded in two pieces when stowed). See [6] for further details.
Magnetometer Boom (MAG Boom) Diagram
------------------------------------------------------------------------
The following diagrams show the location of each sensor on the
Magnetometer boom and the approximate location of the boom in the
spacecraft bus.
-Z Magnetometer Boom side view:
-------------------------------
.---.
| |
------- | | J-MAG Scalar
^ | | Magnetometer
| '---' (MAGSCA)
| | |
| | |
| ~~~
~0.352m ~~~
| | |
| | |
| | |
| .---.
v | |
------- | | J-MAG Outboard Sensor
^ | | (MAGOBS)
| '---'
| | |
| | |
| ~~~
~1.496m ~~~
| | |
| | |
| | | SCM sensor
v .---.| | (RPWI_SCM)
------- ========| |||==========
^ ==========| |==|=======
| | |..
| | |
| | |
| ~~~
| ~ ~~~ ~
~0.413m \ | | /
| \ | | /
| \ | | /
| \ | | /
| \ | |/
v ` . \| | RWI sensor
------- ` .| | (RPWI_RWI)
^ / |`.
| / | |\ ` .
| / | | \ ` .
| / ~~~ \ ` .
| ~ ~~~ ~
| | |
~1.083m | |
| | |
| | |
| | |
| .---.
v | |
------- | | J-MAG Inboard Sensor
^ | | (MAGIBS)
| '---'
| | |
| | |
| ~~~
~7.285m ~~~
| | |
| | |
| |^ +Xmagb
| |||
| |||
v ||| +Ymagb
------- x-------->
+Zmagb
+Zmagb is into
the page
RWI and SCM Dipoles Diagram
------------------------------------------------------------------------
The following diagram show the location of each of the RWI and SCM
dipoles tips within each of the corresponding dipoles.
-Z Magnetometer boom side view:
-------------------------------
rwi_ex_p
~~~ ~
| | /
| |+Xrwi
rwi_ey_m | | ^ rwi_ez_m
~ | | / _~
` < | |/ _.'
+Zrwi` . | | _.'
` .=x|.'
+Yrwi ` .
_.'/ | | ` .
_.' / | | ` .
~' / ~~~ ` ~
rwi_ez_p ~ ~~~ rwi_ey_p
rwi_ex_m | |
| |
rwi_ez_p| |
~ | | MAG boom
| | |
| . | SCM sensor
rwi_ex_m ~========| | |=========~ rwi_ex_p
rwi_ey_m ~=========| |==========~ rwi_ey_p
<----------o----------->
+Xscm | || +Yscm
| |||
| |||
~ |||
rwi_ez_m |v +Zscm
| |
~~~
| |
|^ +Xmagb
|||
|||
||| +Ymagb
x-------->
+Zmagb
Langmuir Probe Booms (LPx Boom) Diagram
------------------------------------------------------------------------
The following diagrams show the location of each of the Langmuir
Probe booms' reference holes and the position of the Langmuir Probe
within each the corresponding boom.
For the orientation of each of the booms, please refer to [7].
+Z s/c side view:
-----------------
direction
of flight
___________ HGA <-------------->
\ /
\ .--`.-----.'--.# LPB1 \
/ | | /
\ | | \
/ | +Zsc +Ysc /
\=>o<===============>o-| o------->o<===============>o<=\
/ -Y Solar Array | | | +Y Solar Array /
\ | | | \
/ LPB2 #.___|__|______. /
\ # | # LPB4 \
LPB3 V +Xsc
+Xswi_base
+Zsc is out of the page.
#LPBx indicates the location of the Langmuir Probe Boom's reference
hole in the boom's mounting plane for boom number x.
+X Langmuir Probe side view:
----------------------------
|
v
------ .---. Langmuir Probe
10 / \
cm | |
------ '...' ---
^ \\ \
| \\ \
\\ \
\\ \
~~ ~2.95m
~~ \
+Ylpb^ \
\\ \ ^ +Zlpb-h
\\ \|
~45deg .-\\ |
,' \\.|\
. .--\|--. +Ylpb-h
//-----------------'--.o------->--------//
.' Langmuir Probe
.' deployment plane (*)
+Zlpb .'
<' +Xlpb-h and
+Xlpb are out of
the page.
(*) Note that the LP deployment plane is the one defined by the
movement of the boom while being deployed from its stowed
configuration.
IK Code Example
---------------------------------------------------------------------------
This section contains an example code, in Python, illustrating how
the position of the RPWI sensors can be retrieved using appropriate
SPICE routine. The examples presented as stand-alone functions, ready
to be cut-n-paste and called from an application by simply replacing
<path-to-meta-kernel>.
import spiceypy
# Load the appropriate Meta-kernel.
spiceypy.furnsh(<path_to_meta-kernel>)
def get_position(utc, origin, body):
'''Get the position of a Body with respect to another
at a given time.
'''
# Convert the UTC time to epehmeris time.
et = spiceypy.utc2et(utc)
# Get the position of the target body with respect to the origin.
pos, lt = spiceypy.spkpos(origin, et, origin, 'NONE', body)
# Calculate the distance.
dist = spiceypy.vnorm(pos)
# Print the distance with an appropriate format.
print(f"{body}{' '*(20-len(body))} {origin}\
{' '*(18-len(origin))} {dist*1000:.3f}")
# Return the distance and position vector in meters.
return dist*1000, pos*1000
# Obtain all the NAIF body names.
body_names = spiceypy.gcpool('NAIF_BODY_NAME', 0, 10000, 80)
# Print the header of the table that will provide the information.
print(f"Body{' '*16} Origin {' '*11} Distance (m)")
print(f"{'='*52}")
# For the RPWI bodies, get the position WRT to the JUICE Mechanical
# Center.
for body_name in body_names:
if 'JUICE_RPWI' in body_name:
get_position('2034-01-01', 'JUICE_SPACECRAFT', body_name)
# Print some extra position of bodies with respect to other bodies.
print("")
get_position('2034-01-01', 'JUICE_RPWI_SCM_EX', 'JUICE_RPWI_SCM_EX_P')
get_position('2034-01-01', 'JUICE_RPWI_SCM_EX', 'JUICE_RPWI_SCM_EX_M')
Executing this code yields a result similar to:
Body Origin Distance (m)
====================================================
JUICE_RPWI_LPB1 JUICE_SPACECRAFT 2.899
JUICE_RPWI_LP1 JUICE_SPACECRAFT 5.806
JUICE_RPWI_LPB2 JUICE_SPACECRAFT 3.709
JUICE_RPWI_LP2 JUICE_SPACECRAFT 6.382
JUICE_RPWI_LPB3 JUICE_SPACECRAFT 1.879
JUICE_RPWI_LP3 JUICE_SPACECRAFT 4.003
JUICE_RPWI_LPB4 JUICE_SPACECRAFT 2.943
JUICE_RPWI_LP4 JUICE_SPACECRAFT 5.875
JUICE_RPWI_RWI JUICE_SPACECRAFT 9.424
JUICE_RPWI_RWI_EX JUICE_SPACECRAFT 9.380
JUICE_RPWI_RWI_EX_P JUICE_SPACECRAFT 10.484
(...)
JUICE_RPWI_SCM_EX_P JUICE_RPWI_SCM_EX 0.102
JUICE_RPWI_SCM_EX_M JUICE_RPWI_SCM_EX 0.102
JUICE_RPWI_LP2 JUICE_RPWI_LP1 6.287
JUICE_RPWI_LP3 JUICE_RPWI_LP1 8.800
JUICE_RPWI_LP4 JUICE_RPWI_LP1 5.256
End of IK file.