Information to be determined is in RED TEXT below.
Information that is subject to change is in GREEN TEXT below.
Last update of this page: May 14, 2025, 9:50 am ET
Payload Ferry Flights and ISS Crew Data
Ferry Vehicle to ISS: TBD, likely a SpaceX vehicle
Current Launch Date: TBD (useful reference NASA Consolidated Launch Schedule at nasa.gov)
Crew: none
Launch Site: TBD, likely Launch Complex (LC) 39A, NASA Kennedy Space Center, FL
Berthing at ISS: 1 to 4 days after launch
Launch Date History:
Initial Launch Date: TBD
Ferry Vehicle for Return to Earth: TBD, likely SpaceX vehicle
Crew: none
Unberth/Landing Date: TBD
Landing Site: splashdown likely off Florida coast
Payload Duration on ISS: nominally 4-6 weeks; expectation 4 weeks
Notable: visit the NASA ISS website for a comprehensive overview of ISS construction, on-orbit research, operations, crews, and multimedia galleries; read about the SpaceX Falcon 9 rocket and Dragon spacecraft
ISS Crew for SSEP Mission 21 Payload Operations: Expedition TBD (see Expeditions Schedule at nasa.gov) crew to be listed once closer to launch date
SSEP Mission 21 to ISS: Payload and Program Data
Payload Designation: SSEP23 – Discovery, named for NASA’s Space Shuttle orbiter Discovery. Watch the launch on the SSEP Launch and On-Orbit Operations History page. Starting with Mission 19 to ISS, SSEP experiment payloads are named for the orbiter vehicles from the NASA Space Shuttle Program. (For SSEP Mission 16-18, experiment payloads were named for NASA’s robotic lunar exploration programs in advance of the Apollo missions; for SSEP Missions 12 to 15, experiment payloads were named for NASA human spaceflight programs; for SSEP Missions 5 to 11, experiment payloads were named for Apollo Command Modules; prior to Mission 5, payloads were named for Apollo Lunar Modules.)
Number of Student Team Flight Experiments: TBD
TBD communities are participating in SSEP Mission 21 to ISS
TBD flight experiments were selected
Payload: Suite of Flight Certified mini-laboratories, specific hardware TBD
Stowage: TBD on ISS
History:
The 23rd SSEP flight opportunity—SSEP Mission 21 to the International Space Station—was announced by the National Center for Earth and Space Science Education (NCESSE) and the Arthur C. Clarke Institute for Space Education on May 14, 2025, with accompanying Video Clips describing SSEP by Center Director, Dr. Jeff Goldstein: Clip 1 (NASA), Clip 2 (NASA)
Current Status:
Flight Opportunity announced for. Mission 21 program start in September 2025.
A List of Important SSEP Mission 21 to ISS Subpages:
SSEP Mission 21 to ISS: Critical Timeline
SSEP Mission 21 to ISS: Mini-Laboratory Operation
SSEP Mission 21 to ISS: Mission Patch Art and Design Competition