Integrated Space Program of the United States 

National Aeronautics and Space Administration (NASA)
Arnold Engineering Development Center (AEDC)

Missile Defense Agency (MDA, former BMDO)
Defense Advanced Research Programs Agency (DARPA)

Federal Aviation Admin's Associate Administrator for Commercial Space Transportation (FAA/AST)
House Science Committee
Los Alamos National Laboratory
Sandia National Laboratory
U.S. Air Force Research Laboratory (AFRL)
U.S. Air Force Space & Missile Systems Center (SMC)
U.S. Army Space & Missile Defense Center (USASMDC)
U.S. Office of Science & Technology Policy
U.S. (Air Force's) Space Command
Spaceport Florida Authority (SFA)
Universities Space Research Association (USRA)

Air War College Gateway to International Space
http://www.au.af.mil/au/awc/awcgate/awc-spci.htm

RKA  Russian Space Agency

http://www.rosaviakosmos.ru/english/erka.html

JAXA  Japan Aerospace Exploration Agency

http://www.jaxa.jp/index_e.html

ESA  European Space Agency

http://www.esa.int/esaCP/index.html

ISRO  Indian Space Research Organization

http://www.isro.org/

CASI  Canadian Aeronautics Space Institute

http://www.casi.ca/index.php

Canadian Space Agency (CSA)

Austrian Space Agency (ASA)

Federal Office for Scientific, Technical and Cultural Affairs, Belgium (OSTCA)
Belgian Institute for Space Aeronomy (BISA)

Bulgarian Aerospace Agency (BASA)

Dansk Rumforskningsinstitut (DRI)
Danish Space Research Institute (DSRI)

European Space Agency (ESA)
European Commission's Space Coordination Group
European Space Science Committee (ESSC)

Technology Development Center of Finland (TEKES)

Centre National d'Etudes Spatiales (CNES) National Center for Space Studies. National Space Agency of France
Office National d'Etudes et de Recherches Aérospatiales (ONERA)
France’s National Office for Aerospace Studies and Research.

Deutches Zentrum für Luft-und Raumfahrt (DLR) German Aerospace Center.

British National Space Center (BNSC) National Space Program of the United Kingdom

Institute for Space Applications and Remote Sensing (ISARS) Greek Space Agency

Magyar Ürkutatasi Iroda (MUI) Hungarian Space Office (HSO)

Agenzia Spaziale Italiana (ASI) Italian Space Agency.

Nationaal Lucht- en Ruimtevaartlaboratorium (NLR)   National Aerospace Laboratory.
Netherlands Agency for Aerospace Programs (NIVR)
Netherlands Agency for Aerospace Programmes (NISO)

Norsk Romsenter, Norwegian Space Center.

Centrum Badan Kosmicznych (CBK)  Polish Space Research Center.

Instituto Nacional de Engenharia e Tecnologia Industrial (INETI)  Portuguese National Institute for Engineering and Industrial Technology.

Agentia Spatiala Româna (ASR). Romanian Space Agency (RoSA)

Rosaviakosmos (RKA) Russian Aeronautics & Space Agency.
Institut Kosmisheskikh Issledovaniy (IKI) Space Research Institute.

Instituto Nacional de Tecnica Aerospacial (INTA) Spanish National Institute for Aerospace Technics.
Centro para el Desarollo Tecnologico Industrial (CDTI) Industrial Technological Development Center.

Rymdstyrelsen. Swedish National Space Board (SNSB)
Rymdbolaget. Swedish Space Corporation (SSC)

Swiss Space Office (SSO)

Natsionalnie Kosmichne Agentsvo Ukrayni (NKAU)  National Space Agency of Ukraine (NSAU).

Comision Nacional de Actividades Espaciales (CONAE) National Commission of Argentina for Space Activities.

Agência Espacial Brasileira (AEB) Brazilian Space Agency.
Centro Técnico Aeroespacial - Instituto de Aeronautica e Espaço (CTA/IAE) Aerospace Technical Center - Institute for Aeronautics & Space.
Instituto Nacional de Pesquisas Espaciais (INPE) National Institute for Space Research.

Comision Nacional de Investigacion y Desarollo Aeroespacial (CONIDA) Peruvian National Commission for Aerospace Research & Development.

Comision Nacional de Investigacion y Desarollo Aeroespacial (CONIDA) Uruguay
National Commission for Aerospace Research & Development.

CSIRO Office of Space Science and Applications (COSSA)
Australian Space Research Institute (ASRI)
Hypersonic Research at the University of Queensland's Department of Mechanical Engineering

China National Space Administration (CNSA)
China Academy of Launch Vehicle Technology
China Great Wall Industry Corporation
Commission of Science, Technology and Industry for National Defense (COSTIND)
Institute for Astronautics Information of China Aerospace Corp. (IAICASC)

Lembaga Penerbangan dan Antariksa Nasional (LAPAN) Indonesian National Institute of Aeronautics and Space. In Javanese.

Bahagian Kajian Sains Angkasa (BAKSA) Malaysian Space Science Studies Division of the Ministry of Science, Technology and the Environment.

Korea Aerospace Research Institute (KARI) South Korea
Korea Advanced Institute of Science & Technology (KAIST)South Korea

National Space Program Office (NSPO) National Space Agency of Taiwan

National Research Council of Thailand (NRCT)

Azerbaijani National Aerospace Agency (ANAKA).Provisional link.

Israel Space Agency (ISA) in Hebrew.

National Space Research & Development Agency(NSRDA)  Space Program of Nigeria

Riyadh Space Research Institute.  National Space Program of Saudi Arabia

Türkiye Bilimsel ve Teknik Arastirma Kurumu (TUBITAK).
The Scientific and Technical Research Council of Turkey. In Turkish.

Bangladesh Space Research & Remote Sensing Organization (SPARRSO)

Indian Space Research Organisation (ISRO)

Kazakh Space Research Institute. National Space Agency of Kazakhstan