% Header options:
% * largeheader;
% * smallheader - small with project logo;
% * compactheader (default) - smaller with project name;
% * largefirstheader - only first page large.
% Front page options:
% * largetitle - use full width for title;
% * nosigs - no signature boxes or CCB data.
% Math typeface option:
% * mathastext - use the same typeface for math as for text.
% Title typeface option:
% * spacemono - switch monospace typeface from DejaVu Sans Mono to
%   Space Mono, if installed.
% Space Mono is not available as a normal package, but it can be
% installed from https://github.com/AnymouseProphet/SpaceMono-LaTeX.
% Get archive SpaceMono-LaTeX-main.zip via Code > Download ZIP. Copy
% contents of directory texmf-tree to your TEXMF-LOCAL directory, given
% by: kpsewhich -var-value TEXMFHOME. If it doesn't exist, create and
% use ~/texmf. Then run: mktexlsr && updmap-user --enable Map=spacemono.map

\documentclass[largetitle]{plain}

% Project name.
\project{PROJECT}

% File name of project logo including extension.
% If not found, text of \project is used.
% Without project logo, consider using class option compactheader.
\projectlogo{project.png}

\documenttype{Document type}

\documentnumber{PROJ-RP-2026-001} % official document number
\institutenumber{} % extra document number for internal use

\issue{0.1}
%\date{\today}

% The Level and Class form a classification:
% Level 1: issued by Customer ('them').
% Level 2: issued by Contractor ('us'), sent to Customer for approval
%          (Class A) prior to implementation. After approval, these
%          documents are contractually binding.
% Level 3: any other issued by Contractor, sent to Customer either for
%          review (Class R, identified discrepancies shall be corrected
%          prior to implementation) or for information (Class I).
% Level -: issued by Contractor, not sent to Customer, i.e. internal
%          documents for information (Class I).
% Class A, R or I as described above.
% If a project does not use it, leave level and class empty.
\level{} % one of: 1, 2, 3, -
\class{} % one of: A, R, I

% The category indicates the authorization level of the document:
% 1. Document to be authorized by client, first authorization by PM.
% 2. End-to-end of system level documents; authorization by PM.
% 3. Document concerning units; authorization by the Unit Manager.
% 4. Document concerning assemblages/sub-assemblages; authorization by the (sub) assembly manager.
% If a project does not use it, leave category empty.
\category{} % one of: 1, 2, 3, 4, N/A

% Given as \title{Title} or \title[Header title]{Front-page title}
\title{Title of the document}

% One person per line: Sarah Lee\\Tom Smith
\author{The Author}
\checkedby{The Checker}
\agreedby{}
\authorisedby{The Manager}
%\pdfauthor{The Institute} % for PDF properties, not title page, default the same as \author

% Optional entries for a configuration item (CI):
\cinumber{} % often a 4-digit number
\model{} % one of: DM, EM, QM, FM, FS (or similar)
\baseline{} % one of: As Required, As Planned, As Designed, As Built, As Verified
\workpackage{}

% Bibliography with .bib file, defining keys of applicable documents (the rest
% will be reference documents).
\addtocategory{AD}{cotton}
\addbibresource{biblatex-examples.bib}


\begin{document}

% \maketitle (without class option nosigs) produces a table with room for 
% signature fields. \maketitle[a,b,c,d] with a, b, c and d each either 0, 1
% or 2 also adds this number of signature fields to the prepared, checked,
% agreed and authorised table cells, respectively, but eforms from the
% acrotex bundle needs to be installed.
\maketitle

\begin{distributionlist}
\item ESA
\end{distributionlist}

\newpage
\begin{changerecordtable}
0.1 & \today & All & Initial version \\
\end{changerecordtable}

\newpage
\tableofcontents

\newpage
\begin{abbreviationtable}
HTML & Hypertext Markup Language \\
\end{abbreviationtable}

% Bibliography with .bib file, also using \addtocategory and
% \addbibresource in the preamble.
\newrefcontext[labelprefix=AD]
\printbibliography[category=AD,heading=AD]
\newrefcontext[labelprefix=RD]
\printbibliography[notcategory=AD,heading=RD]
% Refer in text with \cite{thisdoc} for both categories.


\newpage
\section{Introduction}

Alternative styles for the header, front page, math typeface and title typeface are provided by class options \texttt{largeheader}, \texttt{smallheader}, \texttt{compactheader}, \texttt{largefirstheader}, \texttt{largetitle}, \texttt{nosigs}, \texttt{mathastext} and \texttt{spacemono}. Comments at the start of the \TeX{} file explain their meaning. The body text is in sans-serif typeface DejaVu Sans, an extended version of Vera Sans, which resembles Verdana. Headings are in monospace typeface {\ifspacemono Space Mono\else DejaVu Sans Mono\fi}. Math mode uses {\ifmathastext almost the same sans-serif typeface as body text\else serif typeface Utopia\fi}: \mbox{$2 \times 3 + 7^2 - \sqrt{9} + 10/5 - 6 = 48$}. Compare the characters to those in text mode: 2×3+7\textsuperscript{2}\textminus\textsurd9+10/5\textminus6=48. Use math mode for functions and variables ($f(x)$, $\arcsin y$, $\bm{z}$, $\mathbf{A}$), constants ($\pi$) and expressions ($5x^2+y^3$), but use text mode for numerical values and units (5×10\textsuperscript{24}~µm\textsuperscript{\textminus3}, 22°58\textquotesingle39", \textminus76~\textcelsius{}) and descriptive terms, including chemical elements (H\textsubscript{2}O) and subscript labels of quantity symbols ($a_\text{sat}$). In math mode, roman type {\ifmathastext is produced with \texttt{\textbackslash{}mathrm} and \texttt{\textbackslash{}text} with different spacing\else as in $\max$ is produced with \texttt{\textbackslash{}mathrm} and as in text mode with \texttt{\textbackslash{}text}\fi}, bold italic type is produced with \texttt{\textbackslash{}bm} and bold roman type with \texttt{\textbackslash{}mathbf}.
In text mode, commands for superscripts and subscripts are \texttt{\textbackslash{}textsuperscript} and \texttt{\textbackslash{}textsubscript}, symbols are \textminus{}~\texttt{\textbackslash{}textminus}, \texttimes{}~\texttt{\textbackslash{}texttimes}, \textpm{}~\texttt{\textbackslash{}textpm}, \textdegree{}~\texttt{\textbackslash{}textdegree}, \textquotesingle{}~\texttt{\textbackslash{}textquotesingle}, \textquotedbl{}~\texttt{\textbackslash{}textquotedbl}, \textmu{}~\texttt{\textbackslash{}textmu}, \textohm{}~\texttt{\textbackslash{}textohm}, \textcelsius{}~\texttt{\textbackslash{}textcelsius}, \texteuro{}~\texttt{\textbackslash{}texteuro}, but ×±°"µΩ€ can also be given as Unicode text.

{\ifmathastext Math mode uses the same Latin letters as in text mode, except $Iaifluvwx$.\else Math mode uses the Latin letters in: \textrm{\emph{THE FIVE BOXING WIZARDS JUMP QUICKLY, pack my box with f{}ive dozen liquor jugs,} amazingly few discotheques provide jukeboxes.}\fi} The Greek letters are $\Gamma\Delta\Theta\Lambda\Xi$ $\Pi\Sigma\Upsilon\Phi\Psi\Omega$ $\alpha\beta\gamma\delta\varepsilon\zeta$ $\eta\theta\iota\kappa\lambda\mu$ $\nu\xi\pi\rho\sigma\tau$ $\upsilon\varphi\chi\psi\omega$. Sum $2 \times 3 + 7^2 - \sqrt{9} + 10/5 - 6 = 48$ leaves out $\{[(|a \cdot b|+\lceil x_2 \rceil - \lfloor y \rfloor \pm 5\tfrac{1}{2})]\}$. The cross product \cite{glashow} of two vectors is defined by
%
\begin{equation}
\bm{\alpha} \times \bm{\beta} = \alpha \beta \sin \theta \, \hat{\bm{n}},
\end{equation}
%
the convolution of a Gaussian and a Lorentz distribution \cite{salam, wassenberg} is given by
%
\begin{equation}
\mathcal{F}(x, y) = \int_{-\infty}^\infty \frac{y \mathrm{e}^{-t^2}}{(x-t)^2+y^2}\,\mathrm{d} t = \pi \Re[w(x+i\, y)], \quad w(z)=\mathrm{e}^{-z^2}\mathrm{erfc}(-i\, z), \quad x \in \mathbb{R}, y>0,
\end{equation}
%
with Moore-Penrose pseudoinverse \cite{cotton}
\begin{equation}
\mathbf{K}^+ = (\mathbf{K}^\mathrm{T} \mathbf{K})^{-1} \mathbf{K}^\mathrm{T}
\end{equation}
calculated for example with \fakesc{Python} function \texttt{numpy.linalg.pinv}.


\end{document}