Typos.

src/main/resources/assets/org/orekit/localization/OrekitMessages_fr.utf8

@@ -320,7 +320,7 @@ CCSDS_DATE_INVALID_LENGTH_TIME_FIELD = longueur invalide pour le champ date dans
 CCSDS_DATE_MISSING_AGENCY_EPOCH = époque de référence spécifique agence manquante dans une date CCSDS
 
 # missing mandatory key {0} in CCSDS file {1}
-CCSDS_MISSING_KEYWORD = mot-clef {0} manquant dans le fichier CCDSD {1}
+CCSDS_MISSING_KEYWORD = mot-clef {0} manquant dans le fichier CCSDS {1}
 
 # key {0} is not allowed in format version {1}
 CCSDS_KEYWORD_NOT_ALLOWED_IN_VERSION = le mot-clef {0} n''est pas autorisé dans la version {1} du format

src/site/markdown/architecture/ccsds.md

@@ -33,7 +33,7 @@ Orekit-specific `Section` interface that is used for checks at the end of parsin
 `Metadata` and `Data` are gathered together in a `Segment` structure.
 
 The `org.orekit.files.ccsds.ndm` sub-package defines a single top-level abstract
-class `Ndm`, which stands for Navigation Data Message. All CCDSD messages extend
+class `Ndm`, which stands for Navigation Data Message. All CCSDS messages extend
 this top-level abstract class. `Ndm` is a container for one `Header` and one or
 more `Segment` objects, depending on the message type (for example `Opm` only contains
 one segment whereas `Oem` may contain several segments).