External Stowage Platform
Encyclopedia
External Stowage Platforms (ESPs) are key components of the International Space Station
(ISS). Each ESP is an external pallet that can hold spare parts, also known as Orbital Replacement Unit
s (ORUs), for the space station. As a platform it is not pressurized, but does require electricity to power the heaters of some of the stored equipment. ORUs are attached to the ESP via Flight Releasable Attachment Mechanisms (FRAMs), matching witness plates that mate the ORU to the platform. The structure of the ESP-2 and ESP-3 platform is based on the Integrated Cargo Carrier
(ICC) which was designed for the Space Shuttle, produced by Spacehab, Inc and was not intended to be removed from the payload bay during flight. ESP-2 and ESP-3 are flight-deployable versions of the ICC, whereas ESP-1 is unique in shape (see below) and was delivered to the station attached under an ICC.
of the STS-102
Space Shuttle
mission. It is powered by the Unity Module and has two attach points to store ORUs.
ESP-1 was carried into orbit on the underside of an Integrated Cargo Carrier
, and is smaller and unique in shape over the other ESPs and ELCs, with dimensions approximately 1.5 feet wide by 8 feet long.
ESP-1 holds the following ORUs:
mission. It is much larger than ESP-1 with eight FRAMs creating room for up to eight spare parts (ORUs). Like ESP-1, it is powered by the Unity Module. However unlike ESP-1, ESP-2 is attached to the Quest Joint Airlock using a specialized ESP Attachment Device (ESPAD). ESP-2 and ESP-3 are deployable versions of the integrated cargo carrier and have the same dimensions, approximately 8 feet long and 13 feet wide. The ORUs on ESP-2 are:
Notes:
mission. It has seven attachment sites for ISS spare parts and assemblies, called Orbital Replacement Unit
s (ORUs). The platform also has handrails and attachment points for tethers and foot restraints that astronauts can use while working with the ORUs on the ESP-3. ESP-3, as with ESP-2 are deployable versions of the Integrated Cargo Carrier
and have the same dimensions, approximately 8 feet long and 13 feet wide.
ESP-3 was the first major station element to be installed completely by robotics, using only the shuttle and station’s robotic arms, an external berthing camera system (BCS) and a Photovoltaic Radiator Grapple Fixture (PVRGF). Astronauts robotically installed the platform onto the station's P3 truss segment
during the STS-118
mission’s seventh day.
On January 12, 2010, the station's robotic arm was used again to move ESP-3 from the P3 truss segment UCCAS-1 site. It was grappled by the arm and then transferred down the station's backbone on the mobile transporter. ESP-3 was then attached to its new location on the lower part of S3 truss segment
at the PAS-3 site. Moving the storage platform cleared the way for ExPRESS Logistics Carrier
-3 to be installed during STS-134
.
The ORUs installed on ESP-3 are:
Notes:
CMG & frame on FRAM-4 were removed Aug. 13, 2007 during STS-118
. Support frame was placed on ESP-2, CMG was installed in the Z1.
Nitrogen Tank Assembly (NTA) launched on ESP-3 at FRAM-2 was moved to the S1 truss on June 8, 2008 during STS-124
to replace a depleted tank.
Depleted Nitrogen Tank Assembly (NTA) was stored on FRAM-2 June 8, 2008 thru Nov. 18, 2008 (returned on STS-126
)
International Space Station
The International Space Station is a habitable, artificial satellite in low Earth orbit. The ISS follows the Salyut, Almaz, Cosmos, Skylab, and Mir space stations, as the 11th space station launched, not including the Genesis I and II prototypes...
(ISS). Each ESP is an external pallet that can hold spare parts, also known as Orbital Replacement Unit
Orbital replacement unit
Orbital Replacement Units are key elements of the International Space Station that can be readily replaced when the unit either passes its design life or fails. Examples of ORUs are: pumps, storage tanks, controller boxes, antennas, and battery units. Such units are replaced either by astronauts...
s (ORUs), for the space station. As a platform it is not pressurized, but does require electricity to power the heaters of some of the stored equipment. ORUs are attached to the ESP via Flight Releasable Attachment Mechanisms (FRAMs), matching witness plates that mate the ORU to the platform. The structure of the ESP-2 and ESP-3 platform is based on the Integrated Cargo Carrier
Integrated cargo carrier
Integrated Cargo Carriers were unpressurized flat bed pallet and keel yoke assemblies carried in the Space Shuttle payload bay, but were never removed during flight. Note that External Stowage Platforms 1 thru 3 and ExPRESS Logistics Carriers 1 thru 4 were of similar construction but were intended...
(ICC) which was designed for the Space Shuttle, produced by Spacehab, Inc and was not intended to be removed from the payload bay during flight. ESP-2 and ESP-3 are flight-deployable versions of the ICC, whereas ESP-1 is unique in shape (see below) and was delivered to the station attached under an ICC.
Locations and components
ESP-1
The first of the External Stowage Platforms, called ESP-1, was installed on the port side trunnion pin on the outer hull of the Destiny Laboratory Module on March 13, 2001 during the second EVAExtra-vehicular activity
Extra-vehicular activity is work done by an astronaut away from the Earth, and outside of a spacecraft. The term most commonly applies to an EVA made outside a craft orbiting Earth , but also applies to an EVA made on the surface of the Moon...
of the STS-102
STS-102
STS-102 was a Space Shuttle mission to the International Space Station flown by Space Shuttle Discovery and launched from Kennedy Space Center, Florida...
Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
mission. It is powered by the Unity Module and has two attach points to store ORUs.
ESP-1 was carried into orbit on the underside of an Integrated Cargo Carrier
Integrated cargo carrier
Integrated Cargo Carriers were unpressurized flat bed pallet and keel yoke assemblies carried in the Space Shuttle payload bay, but were never removed during flight. Note that External Stowage Platforms 1 thru 3 and ExPRESS Logistics Carriers 1 thru 4 were of similar construction but were intended...
, and is smaller and unique in shape over the other ESPs and ELCs, with dimensions approximately 1.5 feet wide by 8 feet long.
ESP-1 holds the following ORUs:
- FRAM-1 Pump flow control system (PFCS) added by the STS-102STS-102STS-102 was a Space Shuttle mission to the International Space Station flown by Space Shuttle Discovery and launched from Kennedy Space Center, Florida...
crew - FRAM-2 Direct-current switching unit (DCSU) added by STS-100STS-100STS-100 was a Space Shuttle mission to the International Space Station flown by Space Shuttle Endeavour. STS-100 installed the ISS Canadarm2 robotic arm.- Crew :- Mission parameters :* Mass:** Orbiter liftoff:...
crew
ESP-2
ESP-2 was installed with the assistance of Space Shuttle Discovery's robotic arm and two spacewalkers during the STS-114STS-114
-Original crew:This mission was to carry the Expedition 7 crew to the ISS and bring home the Expedition 6 crew. The original crew was to be:-Mission highlights:...
mission. It is much larger than ESP-1 with eight FRAMs creating room for up to eight spare parts (ORUs). Like ESP-1, it is powered by the Unity Module. However unlike ESP-1, ESP-2 is attached to the Quest Joint Airlock using a specialized ESP Attachment Device (ESPAD). ESP-2 and ESP-3 are deployable versions of the integrated cargo carrier and have the same dimensions, approximately 8 feet long and 13 feet wide. The ORUs on ESP-2 are:
- FRAM-1 (top side) empty
- FRAM-2 (top side) Direct Current Switching Unit (DCSU) (added by STS-123STS-123-Mission parameters:* Mass:* Orbiter liftoff: * Orbiter landing: * Perigee: 336 kilometers * Apogee: 346 kilometers * Inclination: 51.6 degrees* Period: 91.6min-Mission payloads:...
crew) - FRAM-3 (top side) Direct Current Switching Unit (DCSU) (added by STS-123STS-123-Mission parameters:* Mass:* Orbiter liftoff: * Orbiter landing: * Perigee: 336 kilometers * Apogee: 346 kilometers * Inclination: 51.6 degrees* Period: 91.6min-Mission payloads:...
crew) - FRAM-4 (top side) Main Bus Switching Unit (MBSU) launched on ESP-2
- FRAM-5 (keel side) Pitch/Roll Joint (P/R-J) added by STS-123STS-123-Mission parameters:* Mass:* Orbiter liftoff: * Orbiter landing: * Perigee: 336 kilometers * Apogee: 346 kilometers * Inclination: 51.6 degrees* Period: 91.6min-Mission payloads:...
crew - FRAM-6 (keel side) Main Bus Switching Unit (MBSU) added by STS-120STS-120-Crew notes:As commander of STS-120, Pamela Melroy became the second woman to command a space shuttle mission. Additionally, the Expedition 16 crew that received STS-120 was commanded by Peggy Whitson, the first female ISS commander...
crew - FRAM-7 (keel side) Flex Hose Rotary Coupler (FHRC-3) launched on ESP-2
- FRAM-8 (keel side) Utility Transfer Assembly (UTA) launched on ESP-2
Notes:
- Video Stanchion Support Assembly (VSSA) launched on ESP-2 at FRAM-2 was jettisoned overboard on July 23, 2007 (the video stanchions were placed on the truss during EVAs).
- Pump Module (PM) (s/n 4), initially installed on FRAM-1 during STS-121STS-121STS-121 was a space shuttle mission to the International Space Station flown by Space Shuttle Discovery. The main purposes of the mission were to test new safety and repair techniques introduced following the Columbia disaster of February 2003 as well as to deliver supplies, equipment and...
, was removed on August 17, 2010 and installed on S1 Truss, replacing a failed PM. The failed unit had been temporarily stored on an ORU site on the MBS, then moved to ESP-2 by the STS-133STS-133STS-133 was the 133rd mission in NASA's Space Shuttle program; during the mission, Space Shuttle Discovery docked with the International Space Station. It was Discoverys 39th and final mission. The mission launched on 24 February 2011, and landed on 9 March 2011...
crew, then returned to earth by the STS-135STS-135STS-135 was the final mission of the American Space Shuttle program. It used the orbiter Atlantis and hardware originally processed for the STS-335 contingency mission, which was not flown. STS-135 launched on 8 July and was originally scheduled to land on 20 July 2011, but the mission was...
crew July 13, 2011. - A failed Control Moment Gyroscope was installed on FRAM-5 from August 13, 2007 during STS-118STS-118- Crew notes :Astronaut Clayton Anderson originally was slated to be launched to the ISS on this mission, but was moved to STS-117. His replacement was Alvin Drew....
until February 13, 2008 when it was returned by STS-122STS-122STS-122 was a NASA Space Shuttle mission to the International Space Station , flown by the Space Shuttle Atlantis. STS-122 marked the 24th shuttle mission to the ISS, and the 121st space shuttle flight since STS-1....
.
ESP-3
ESP-3 was installed on the P3 Truss at UCCAS-1 on August 14, 2007 during the Space Shuttle STS-118STS-118
- Crew notes :Astronaut Clayton Anderson originally was slated to be launched to the ISS on this mission, but was moved to STS-117. His replacement was Alvin Drew....
mission. It has seven attachment sites for ISS spare parts and assemblies, called Orbital Replacement Unit
Orbital replacement unit
Orbital Replacement Units are key elements of the International Space Station that can be readily replaced when the unit either passes its design life or fails. Examples of ORUs are: pumps, storage tanks, controller boxes, antennas, and battery units. Such units are replaced either by astronauts...
s (ORUs). The platform also has handrails and attachment points for tethers and foot restraints that astronauts can use while working with the ORUs on the ESP-3. ESP-3, as with ESP-2 are deployable versions of the Integrated Cargo Carrier
Integrated cargo carrier
Integrated Cargo Carriers were unpressurized flat bed pallet and keel yoke assemblies carried in the Space Shuttle payload bay, but were never removed during flight. Note that External Stowage Platforms 1 thru 3 and ExPRESS Logistics Carriers 1 thru 4 were of similar construction but were intended...
and have the same dimensions, approximately 8 feet long and 13 feet wide.
ESP-3 was the first major station element to be installed completely by robotics, using only the shuttle and station’s robotic arms, an external berthing camera system (BCS) and a Photovoltaic Radiator Grapple Fixture (PVRGF). Astronauts robotically installed the platform onto the station's P3 truss segment
Integrated Truss Structure
the Integrated Truss Structure forms the backbone of the International Space Station, with mountings for unpressurized logistics carriers, radiators, solar arrays, and other equipment.-History:...
during the STS-118
STS-118
- Crew notes :Astronaut Clayton Anderson originally was slated to be launched to the ISS on this mission, but was moved to STS-117. His replacement was Alvin Drew....
mission’s seventh day.
On January 12, 2010, the station's robotic arm was used again to move ESP-3 from the P3 truss segment UCCAS-1 site. It was grappled by the arm and then transferred down the station's backbone on the mobile transporter. ESP-3 was then attached to its new location on the lower part of S3 truss segment
Integrated Truss Structure
the Integrated Truss Structure forms the backbone of the International Space Station, with mountings for unpressurized logistics carriers, radiators, solar arrays, and other equipment.-History:...
at the PAS-3 site. Moving the storage platform cleared the way for ExPRESS Logistics Carrier
EXPRESS Logistics Carrier
An ExPRESS logistics carrier is an unpressurized attached payload platform for the International Space Station that provides mechanical mounting surfaces, electrical power, and command and data handling services for Orbital Replacement Units as well as science experiments on the ISS...
-3 to be installed during STS-134
STS-134
STS-134 was the penultimate mission of NASA's Space Shuttle program. The mission marked the 25th and final flight of . This flight delivered the Alpha Magnetic Spectrometer and an ExPRESS Logistics Carrier to the International Space Station. Mark Kelly served as the mission commander...
.
The ORUs installed on ESP-3 are:
- FRAM-1 (top side) Pitch/roll joint (P/R‐J) launched on ESP-3
- FRAM-2 (top side) Flex Hose Rotary Coupler (FHRC) added by STS-126STS-126-Crew notes:Originally scheduled to fly on STS-126 was Joan E. Higginbotham, who was a mission specialist on STS-116. On 21 November 2007, NASA announced a change in the crew manifest due to Higginbotham's decision to leave NASA to take a job in the private sector. Stephen G...
crew - FRAM-3 (top side) Pump Module (PM) was added by STS-127STS-127STS-127 was a NASA Space Shuttle mission to the International Space Station . It was the twenty-third flight of . The primary purpose of the STS-127 mission was to deliver and install the final two components of the Japanese Experiment Module: the Exposed Facility , and the Exposed Section of the...
crew - FRAM-4 (top side) Linear Drive Unit (LDU) added by STS-127STS-127STS-127 was a NASA Space Shuttle mission to the International Space Station . It was the twenty-third flight of . The primary purpose of the STS-127 mission was to deliver and install the final two components of the Japanese Experiment Module: the Exposed Facility , and the Exposed Section of the...
crew - FRAM-5 (keel side) Space-to-Ground Antenna (SGANT) added by STS-127STS-127STS-127 was a NASA Space Shuttle mission to the International Space Station . It was the twenty-third flight of . The primary purpose of the STS-127 mission was to deliver and install the final two components of the Japanese Experiment Module: the Exposed Facility , and the Exposed Section of the...
crew - FRAM-6 (keel side) Battery Charge/Discharge Unit (BCDU) launched on ESP-3
- FRAM-7 (keel side) empty
Notes:
CMG & frame on FRAM-4 were removed Aug. 13, 2007 during STS-118
STS-118
- Crew notes :Astronaut Clayton Anderson originally was slated to be launched to the ISS on this mission, but was moved to STS-117. His replacement was Alvin Drew....
. Support frame was placed on ESP-2, CMG was installed in the Z1.
Nitrogen Tank Assembly (NTA) launched on ESP-3 at FRAM-2 was moved to the S1 truss on June 8, 2008 during STS-124
STS-124
STS-124 was a Space Shuttle mission, flown by Space Shuttle Discovery to the International Space Station. Discovery launched on 31 May 2008 at 17:02 EDT, moved from an earlier scheduled launch date of 25 May 2008, and landed safely at the Kennedy Space Center's Shuttle Landing Facility, at 11:15...
to replace a depleted tank.
Depleted Nitrogen Tank Assembly (NTA) was stored on FRAM-2 June 8, 2008 thru Nov. 18, 2008 (returned on STS-126
STS-126
-Crew notes:Originally scheduled to fly on STS-126 was Joan E. Higginbotham, who was a mission specialist on STS-116. On 21 November 2007, NASA announced a change in the crew manifest due to Higginbotham's decision to leave NASA to take a job in the private sector. Stephen G...
)
See also
- ExPRESS logistics carrierEXPRESS Logistics CarrierAn ExPRESS logistics carrier is an unpressurized attached payload platform for the International Space Station that provides mechanical mounting surfaces, electrical power, and command and data handling services for Orbital Replacement Units as well as science experiments on the ISS...
- Integrated cargo carrierIntegrated cargo carrierIntegrated Cargo Carriers were unpressurized flat bed pallet and keel yoke assemblies carried in the Space Shuttle payload bay, but were never removed during flight. Note that External Stowage Platforms 1 thru 3 and ExPRESS Logistics Carriers 1 thru 4 were of similar construction but were intended...
- Scientific research on the ISSScientific research on the ISSScientific Research on the International Space Station is a collection of experiments that require one or more of the unusual conditions present in low Earth orbit. The primary fields of research include human research, space medicine, life sciences, physical sciences, astronomy and meteorology...