ISO INTERNATIONAL STANDARD 26143 Third edition 2021-06 Space data and information transfer systems Space link extension (SLE) Return operational control fields service specification Systemes de transfert des donnees et informations spatiales- Extension de liaisons spatiales (SLE) - Service des champs de controlederetouropérationnel Reference number IS026143:2021(E) ISO IS02021 IS0 26143:2021(E) COPYRIGHTPROTECTED DOCUMENT @IS02021 All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting below or Iso's member body in the country of the requester. IsO copyright office CP 401 : Ch. de Blandonnet 8 CH-1214 Vernier, Geneva Phone: +41 22 749 01 11 Email: [email protected] Website: www.iso.org Published in Switzerland ii @ IS0 2021 - All rights reserved