\section{Electrical, Thermal, and Mechanical Requirements}
\label{sec:e-t-m}



%----------------------------------------------------------------------------------
\subsection*{R-AHEPaM-034: Power}
\label{req:R-034}
The power consumption of the unit shall be $\le 15\,$W continuous load. 

\paragraph{Justification:} ESA-ATHENA-ESTEC-PL-SP-0001, ATHENA AHEPaM Specification

\paragraph{Verification:} Analysis/Test

\paragraph{Comments:} The peak power may be higher (currently unspecified).

\paragraph{CAU Response:} The power consumption of the AHEPaM unit will be $\le 15\,$W in continuous load.

%----------------------------------------------------------------------------------
\subsection*{R-AHEPaM-035: Power interface}
\label{req:R-035}
The AHEPaM shall be powered through the SC power interface. It is also used to turn ON/OFF the instrument, to monitor its status (ON or OFF) and to remotely measure the temperature of the AHEPaM. The signals of the SC Power Interface are defined in the following figure.

\begin{center}
    \begin{tabular}{|ll|}\hline
       Signal Name  & Description \\ \hline
    Thermistor     &   Thermistor for remote measurement of the unit’s temperature\\
    ON\_CMD &  HCL command to turn the unit ON \\
    OFF\_CMD &  HCL command to turn the unit OFF\\
    ON\_OFF\_status &  Status of the unit\\
    Primary bus voltage &  Primary bus (+28.0\,V or +50.0\,V)\\\hline
    \end{tabular}
\end{center}

\paragraph{Justification:} ESA-ATHENA-ESTEC-PL-SP-0001, ATHENA AHEPaM Specification

\paragraph{Verification:} Analysis/Test

\paragraph{Comments:} Unit power interface is designed for +28.0\,V.

\paragraph{CAU Response:} The proposed part Teledyne TR-HIREL-1/422
from ESA-ATHENA-ESTEC-PL-SP-0001 will be used for ON/OFF command and unit status.

%----------------------------------------------------------------------------------
\subsection*{R-AHEPaM-036: ON/OFF}
\label{req:R-036}
The AHEPaM shall be switched ON using a high-voltage high power command (HV-HPC) %ac
The AHEPaM shall be turned OFF using a high-voltage high power command (HV-HPC) %ac
The status (ON/OFF) of the AHEPaM shall be monitored using a 422 relay. The interface standard is a bi-level standard monitor (BSM) %ac

\paragraph{Justification:} ESA-ATHENA-ESTEC-PL-SP-0001, ATHENA AHEPaM Specification

\paragraph{Verification:} Analysis/Test

\paragraph{Comments:} Teledyne TR-HIREL-1/422 will be used

\paragraph{CAU Response:} This ON/OFF requirement will be fulfilled with the use of Teledyne TR-HIREL-1/422 bi-level 422 relay.

%----------------------------------------------------------------------------------
\subsection*{R-AHEPaM-037: Primary bus voltage}
\label{req:R-037}
The AHEPaM power interface shall be compatible with a primary bus voltage of either +28\,V or +50\,V. 

\paragraph{Justification:} ESA-ATHENA-ESTEC-PL-SP-0001, ATHENA AHEPaM Specification

\paragraph{Verification:} Analysis/Test

\paragraph{Comments:} Unit power interface is designed for +28.0\,V.

\paragraph{CAU Response:} +28.0\,V is the input voltage of our choice.

%----------------------------------------------------------------------------------
\subsection*{R-AHEPaM-038: Data rate}
\label{req:R-038}
The data-generation rate of the AHEPaM shall be up to 1\,kbps (adjustable).

\paragraph{Justification:} 

\paragraph{Verification:} Analysis/Test

\paragraph{Comments:} 

\paragraph{CAU Response:} \textcolor{blue}{As discussed in the clarification meeting on April 4, 2022, we would appreciate an increase by a few kbps. The exact value needs to be determined and will be communicated to ESA. Then we will need to agree on what can be done.}

%----------------------------------------------------------------------------------
\subsection*{R-AHEPaM-039: Thermal limits}
\label{req:R-039}
The operating and non-operating temperature limits required by the AHEPaM are:

\begin{center}
    \begin{tabular}{|lr|}\hline
Non-Operating: & $-50\,^\circ$C to $+50\,^\circ$C\\
Operating : & $-40\,^\circ$C to $+40\,^\circ$C\\\hline
    \end{tabular}
\end{center}

\paragraph{Justification:} ESA-ATHENA-ESTEC-PL-SP-0001, ATHENA AHEPaM Specification

\paragraph{Verification:} Analysis/Test

\paragraph{Comments:}
The driving force behind \acs{AHEPaM}'s thermal design is to keep its particle detectors at the design temperature at $0\,^{\circ}$C. The second limiting threshold for the moment is the \acs{PMT}'s cold op/ non-op temperature of -30$^{\circ}$C . While the first is a requirement that directly influences \acs{AHEPaM}'s performance, the second stems from the manufacturer's data sheet and is currently under investigation.\newline
However the initial \ac{TMM} \cite{ahepam-djf} shows, that the instrument design can be adapted in order to withstand the required hot op and non-op temperatures. The results indicate that the instrument might, besides its surfaces which will be used as radiators, require external radiators in the range of A$_{\mathrm{RAD}}$=0.01..0.03\,m$^2$ assuming direct solar illumination at 1\,AU. This would furthermore result in required operational heating power.\newline
%This strongly depends on the level of external heat intake of the unit, which is, at this point, just an assumption to understand the fundamental behaviour of the proposed instrument design. 

\paragraph{CAU Response:} Open. The instrument team expresses the necessity for a detailed discussion about the detailed thermal constraints imposed to the instrument. The most important aspect is the amount of external heat applied to the unit by e.g. solar illumination.

%----------------------------------------------------------------------------------
\subsection*{R-AHEPaM-040: Thermal IF area}
\label{req:R-040}
The conductive thermal interface of the AHEPaM box shall be maintained within a maximum of 75'000\,mm$^2$ (PRODUCT LENGTH.WIDTH)


\paragraph{Justification:} 

\paragraph{Verification:} Design/Analysis

\paragraph{Comments:} The driving force behind \acs{AHEPaM}'s design is to keep its detecors cold. Therefore we try to insulate the unit from the S/C by limiting the instrument's feet contact area to a structural minimum. 

\paragraph{CAU Response:}The instrument design is compliant with the requirement.\\

%----------------------------------------------------------------------------------
\subsection*{R-AHEPaM-041: \acs{AHEPaM} TRP}
\label{req:R-041}
The conductive thermal interface shall be set so that the AHEPaM \ac{TRP} is maintained within OP ranges ($-40\,^\circ$C / $+40\,^\circ$C):\\ %\ac{OP}

\begin{center}
    \begin{tabular}{|lr|}\hline
Worst hot case: & TRP shall be set at $+40\,^\circ$C\\
Worst cold case: & TRP shall be set at $-40\,^\circ$C\\\hline
    \end{tabular}
\end{center}


\paragraph{Justification:} 

\paragraph{Verification:} Analysis/Test

\paragraph{Comments:} Please refer to the comment in R-AHEPaM-039.

\paragraph{CAU Response:} Open. Please refer to R-AHEPaM-039.

%----------------------------------------------------------------------------------
\subsection*{R-AHEPaM-042: Radiative thermal IF}
\label{req:R-042}
The radiative thermal interface of the AHEPaM box is N/A


\paragraph{Justification:} 

\paragraph{Verification:} 

\paragraph{Comments:} The instrument team does not understands the ``not applicable'' status of a radiative thermal interface, because radiative coupling is a physical principle.

\paragraph{CAU Response:} Open. Please provide further details to understand the text of the requirement.
%----------------------------------------------------------------------------------

\subsection*{R-AHEPaM-043: Thermal design}
\label{req:R-043}
The thermal design shall ensure that all internal components, material and processes are compatible with the NOP range ($-50\,^\circ$C / $+50\,^\circ$C), when the unit is OFF. %\ac{NOP}


\paragraph{Justification:} 

\paragraph{Verification:} Analysis/Test

\paragraph{Comments:} Please refer to the comment in R-AHEPaM-039.

\paragraph{CAU Response:} Open. Please refer to R-AHEPaM-039.

%----------------------------------------------------------------------------------
\subsection*{R-AHEPaM-044: Thermal stability}
\label{req:R-044}
The conductive interface short term temperature stability shall be 1\,$^\circ$C (\acs{TBC}) for the duration of the measurement.


\paragraph{Justification:} 

\paragraph{Verification:} Analysis/Test

\paragraph{Comments:} See the CAU response below.

\paragraph{CAU Response:} The instrument asks for clarification: What does ``for the duration of the measurement'' mean? We expect \ac{AHEPaM} to be ON at all times. \ac{GCR} fluxes are low and we can not achieve the required measurement statistics if \acs{AHEPaM} is OFF for a substantial fraction of the operational time.

%----------------------------------------------------------------------------------
\subsection*{R-AHEPaM-045: Conductive IF stability}
\label{req:R-045}
The conductive interface long term stability is N/A


\paragraph{Justification:} 

\paragraph{Verification:} Analysis/Test

\paragraph{Comments:} See the CAU response below.

\paragraph {CAU Response:} Please provide more information/ clarify the requirement regarding its applicability towards the instruments thermal design. Does this mean there is no long term stability requirement?

%----------------------------------------------------------------------------------
\subsection*{R-AHEPaM-046: Conductive IF temperature gradient}
\label{req:R-046}
The conductive interface temperature gradient shall not exceed 3\,$^\circ$C (\acs{TBC})  


\paragraph{Justification:} 

\paragraph{Verification:} Analysis/Test

\paragraph{Comments:} a) For a \textit{gradient} a time domain is missing. b) It is unclear, to which side of the conductive interface this requirement applies.

\paragraph{CAU Response:} Open until a transient analysis or test has been conducted. Please clarify the time, to which the given amount references. (The instrument team assumes it to referenced to minutes.)\newline

%----------------------------------------------------------------------------------
\subsection*{R-AHEPaM-047: \acs{AHEPaM} mass}
\label{req:R-047}
The total Nominal Mass (unit Basic Mass + DMM) of the AHEPaM shall be $\le$15\,kg (\acs{TBC}). The location of the \ac{CoG} can be considered at the geometric centroid of the defined volume. %\acs{DMM}


\paragraph{Justification:} 

\paragraph{Verification:} Analysis

\paragraph{Comments:} The requirement is clear for the mass allocation. The \ac{CoG} part seems to be missing a radius for the stated centroid in order to check compliance of \acs{AHEPaM} against it.

\paragraph{CAU Response:} The instrument design is complient with the requirment regarding the mass allocation.\newline
Please provide a radius for the stated centroid. However -- due to its symmetric shape, the instrument's \ac{CoG} will be close to the center of its envelope in XY direction. Due to the heavy \acs{BGO}s, the Z position will likely vary.

%----------------------------------------------------------------------------------
\subsection*{R-AHEPaM-048: Dimensions}
\label{req:R-048}
The dimensions of the mechanical design are as per the following table and figure.

\begin{center}
 \begin{tabular}{|lrl|}\hline
Parameter & Value & Unit \\\hline
Length & 300 & mm \\
Width & 250 & mm \\
Maximum height & 200 & mm \\
Volume & 15'000'000 & mm$^3$ \\ 
Mounting area$^*$ &  92'400 & mm$^2$ \\\hline
\multicolumn{3}{l}{*Include 20\,mm boundary for mounting feet.}
 \end{tabular}
 \end{center}

\begin{center}
    \includegraphics[width=0.5\textwidth]{cau-ath-req-0004_i1-0/dimensions-sketch.png}
\end{center}


\paragraph{Justification:} 

\paragraph{Verification:} Design Review

\paragraph{Comments:} None.

\paragraph{CAU Response:} Not compliant for maximum height and volume.\newline
\acs{AHEPaM} will exceed the allocated volume box by 35,2\,mm in (instrument's) Z direction.\newline
It will exceed the allocated volume by 2'909'539 mm$^2$. However, this just applies to the projected envelope box and not to the real volume consumed by the structure.\\

Please refer to the \ac{MICD} \cite{ahepam-micd} for details. %M-Mechanical Interface Control Document.

%----------------------------------------------------------------------------------
\subsection*{R-AHEPaM-110: Global resonance}
\label{req:R-110}
The Unit shall have a hard-mounted 1st global resonance $\geq$140\,Hz.


\paragraph{Justification:} Generic for small units. To stay out of low-frequency sinusoidal and transient dynamic excitation.


\paragraph{Verification:} Analysis/Test

\paragraph{Comments:} None.

\paragraph{CAU Response:} The instrument design is compliant with the requirement.

%----------------------------------------------------------------------------------
\subsection*{R-AHEPaM-120: Design limit load}
\label{req:R-120}
The Unit shall be dimensioned considering the following Design Limit Load that may act in any direction:
30\,g.

\paragraph{Justification:} Generic for small units in a mass range from 10-20\,kg. Derived from Mass Acceleration Curve (MAC, NASA-HDBK-7005). %cite

\paragraph{Verification:} Analysis/Test

\paragraph{Comments:} None.

\paragraph{CAU Response:} The instrument design load is compliant with the requirement.

%----------------------------------------------------------------------------------
\subsection*{R-AHEPaM-130: Shock environment}
\label{req:R-130}
The Unit shall be designed to meet performance requirements following exposure to the externally induced qualification shock environment at the Unit interface specified in the table below (\acs{TBC}):

\begin{center}
\begin{tabular}{|lr|}\hline
100\,Hz    &              20\,g\\
400\,Hz     &           350\,g\\
10000\,Hz    &       350\,g\\\hline
\end{tabular}
\end{center}

\paragraph{Justification:} Preliminary estimate for Unit in SVM considering S/C clampband release and SA HDRM release shock sources. %\ac{SVM} \ac{SA} \ac{HDRM}


\paragraph{Verification:} Analysis/Test

\paragraph{Comments:} None.

\paragraph{CAU Response:} The instrument design is compliant with the requirement.

%----------------------------------------------------------------------------------
\subsection*{R-AHEPaM-140: Sine vibration}
\label{req:R-140}
The AHEPaM Unit shall sustain the following sinusoidal vibration qualification levels with a qualification sweep rate of 2\,Oct/min.:

\begin{center}
    Lateral \& Axial: 5-100\,Hz: 30\,g

\end{center}

No notching allowed unless agreed by the Agency.


\paragraph{Justification:} Tolerances as given by (ECSS-E-ST-10-03C):

\begin{center}
\begin{tabular}{|lr|}\hline
Frequency: & $\pm 2\%$ (or $\pm1\,$Hz whichever is greater)\\
Amplitude: & $\pm 10\%$\\
Sweep rate (Oct/min): & $\pm 5\%$ \\\hline
\end{tabular}
\end{center}


\paragraph{Verification:} Analysis/Test

\paragraph{Comments:} The amplitude of 30\,g seems to be very high.

\paragraph{CAU Response:} The instrument team asks for a verification of the amplitude value of 30\,g.

%----------------------------------------------------------------------------------
\subsection*{R-AHEPaM-150: Accoustic environment}
\label{req:R-150}
The Unit shall sustain the acoustic \ac{SPL} spectrum defined in the [Ariane 6 User's Manual].


\paragraph{Justification:} 1:1 copy of the \ac{SPL} spectrum in A-6 MUA. %\ac{MUA}

\paragraph{Verification:} Open. 

\paragraph{Comments:} Where can the instrument team obtain the stated User's Manual?


\paragraph{CAU Response:} Please provide the stated document for review by the instrument team.

%----------------------------------------------------------------------------------
\subsection*{R-AHEPaM-160: Random vibration qualification levels}
\label{req:R-160}
The Unit shall sustain the following random vibration qualification levels:

\begin{center}
\begin{tabular}{|lr|}
\multicolumn{2}{l}{Lateral \& Axial:} \\\hline
20-100\,Hz   &              $+3\,$dB/Oct\\
100-300\,Hz  &             0.263\,g$^2$/Hz\\
300-2000\,Hz &            $-5\,$dB/Oct\\
rms:        &                   12.2\,g\\\hline
\end{tabular}
\end{center}

The duration of the qualification tests is 2\,min for all three axes.
Notching is not allowed unless agreed by the Agency.


\paragraph{Justification:} The specification is taken from \ac{ECSS}-E-10-03A(15Feb2002).

\begin{center}
\begin{tabular}{|lr|}
\multicolumn{2}{l}{Tolerances (ECSS-E-ST-10-03C):} \\\hline
20-1000\,Hz: & $-1\,$dB / $+3\,$dB \\
1000-2000\,Hz: & $\pm 3\,$dB \\
Overall grms: & $\pm 10\%$ \\\hline
\end{tabular}
\end{center}

\paragraph{Verification:} Analysis/Test

\paragraph{Comments:} None

\paragraph{CAU Response:} The instrument design is compliant with the requirement.



