| Jabiru-1 | 2015 | NewSat | Ariane 5 ECA |
| Jackal-0004 | May 3, 2026 | True Anomaly | Falcon 9 Block 5 |
| Jam-e Jam 1 | February 12, 2026 | Islamic Republic of Iran Broadcasting | Proton-M |
| Jamal 201 | November 24, 2003 | Gazprom Space Systems | Proton-K |
 James Webb Space Telescope | December 25, 2021 | Goddard Space Flight Center, Space Telescope Science Institute | Ariane 5 ECA |
 Janus-1 | February 10, 2023 | — | Small Satellite Launch Vehicle |
| JAS-2 | August 17, 1996 | — | H-II |
 Jason-1 | December 7, 2001 | National Aeronautics and Space Administration, CNES | Delta II |
 Jason-3 | January 17, 2016 | National Aeronautics and Space Administration, EUMETSAT, CNES, National Oceanic and Atmospheric Administration | Falcon 9 v1.1 |
 JAWSAT | January 27, 2000 | — | Minotaur I |
| JCSAT-1 | March 6, 1989 | JSAT Corporation | Ariane 44LP |
| JCSAT-11 | September 5, 2007 | — | Proton-M |
| JCSAT-110 | October 6, 2000 | SKY Perfect JSAT Holdings | Ariane 42L |
| JCSAT-13 | May 15, 2012 | — | Ariane 5 ECA |
| JCSAT-15 | December 21, 2016 | SKY Perfect JSAT Holdings | Ariane 5 ECA |
| JCSAT-17 | February 18, 2020 | SKY Perfect JSAT Holdings | Ariane 5 ECA |
| JCSAT-18/Kacific-1 | December 17, 2019 | SKY Perfect JSAT Corporation, Kacific Broadband Satellites | Falcon 9 Block 5 |
| JCSAT-1B | December 2, 1997 | — | Ariane 44P |
| JCSAT-2 | January 1, 1990 | JSAT Corporation | Commercial Titan III |
| JCSAT-2A | March 29, 2002 | — | Ariane 44L |
| JCSAT-2B | May 6, 2016 | SKY Perfect JSAT Holdings | Falcon 9 Full Thrust |
| JCSAT-3 | August 29, 1995 | — | Atlas II |
| JCSAT-3A | August 11, 2006 | — | Ariane 5 ECA |
| JCSAT-4A | February 16, 1999 | SKY Perfect JSAT Holdings | Atlas II |
| JCSAT-5A | April 12, 2006 | SKY Perfect JSAT Holdings | Zenit-3SL |
| JCSAT-RA | August 21, 2009 | SKY Perfect JSAT Holdings | Ariane 5 ECA |
| JDRS-1 | November 29, 2020 | — | H-IIA |
| JERS-1 | February 11, 1992 | — | H-I |
| Jikiken | September 16, 1978 | Institute of Space and Astronautical Science | M-3H |
| Jilin 1-03 | January 9, 2017 | — | Kuaizhou |
| Jilin-1 GX-A | October 7, 2015 | — | Long March 2D |
 Johannes Kepler ATV | February 16, 2011 | European Space Agency | Ariane 5ES |
| JSAT-136 | August 14, 2008 | SKY Perfect JSAT Holdings | Ariane 5 ECA |
| JSAT-144C | August 14, 2016 | SKY Perfect JSAT Holdings | Falcon 9 Full Thrust |
| Jugnu | October 12, 2011 | Indian Institute of Technology Kanpur | Polar Satellite Launch Vehicle |
 Jules Verne ATV | March 9, 2008 | European Space Agency | Ariane 5ES |
 Juno | August 5, 2011 | Jet Propulsion Laboratory | Atlas V 551 |
 Jupiter Atmospheric Probe | October 18, 1989 | Ames Research Center | Space Shuttle |
 Jupiter Icy Moons Explorer | April 14, 2023 | European Space Agency | Ariane 5 ECA |
 Jupiter Icy Moons Orbiter | 2017 | — | Delta IV Heavy |
| Juventas | October 7, 2024 | European Space Agency | Falcon 9 Block 5 |
| JY1-SAT | December 3, 2018 | — | Falcon 9 |