ExPRESS Logistics Carrier number 1
ExPRESS Logistics Carrier number 1

An EXpedite the PRocessing of Experiments to Space Station (ExPRESS) Logistics Carrier (ELC) is an unpressurized attached payload platform for the International Space Station (ISS) that provides mechanical mounting surfaces, electrical power, and command and data handling services for Orbital Replacement Units (ORUs) as well as science experiments on the ISS. The ELCs were developed primarily at the Goddard Space Flight Center in Greenbelt, Maryland, with support from JSC, KSC, and MSFC. ELC was formerly called "Express Pallet" and is the unpressurized counterpart to the pressurized ExPRESS Rack. An ELC provides scientists with a platform and infrastructure to deploy experiments in the vacuum of space without requiring a separate dedicated Earth-orbiting satellite.

ELCs interface directly with the ISS integrated truss common attach system (CAS).[1] The P3 Truss has two such attach points called Unpressurised Cargo Carrier Attachment System (UCCAS) mechanisms, one facing zenith (space facing) called UCCAS-1, the other facing nadir (earth facing) called UCCAS-2. The S3 Truss has four similar locations called Payload Attachment System (PAS) mechanisms, two facing Zenith (PAS-1 and PAS-2), and two facing Nadir (PAS-3 and PAS-4).

Description

Layout and structure of the ELC
Layout and structure of the ELC
ELC steel framework during final fabrication at GSFC
ELC steel framework during final fabrication at GSFC

The ELC are four un-pressurized attached payloads, some designed by the Brazilian Space Agency,[2] for the International Space Station (ISS) that provides mechanical mounting surfaces, electrical power, and command and data handling services for science experiments on the ISS. The ELCs have a deck size of about 14 feet by 16 feet and spans the width of the space shuttle's payload bay. They are made of steel, coated with UV paint. Each one is capable of providing scientists with a platform and infrastructure to deploy experiments in the vacuum of space without requiring a separate dedicated Earth-orbiting satellite. Each carrier is capable of carrying 9,800 lbs. to orbit and will also serve as parking fixtures for spare ISS hardware (ORUs) which can be retrieved when needed.[3] Experiments are mounted on ExPRESS payload adapters (ExPA) which are about the same size as the FRAMs that hold ORUs.

Electrical subsystem ExPRESS carrier avionics (ExPCA)

Within the electrical subsystem of the ELC, the ExPRESS carrier avionics (ExPCA) provides electrical power distribution to experiments, and data interfaces to the ISS. Within the ExPCA, the ColdFire-based flight computer, software, and related electronics comprise its "flight controller unit" (FCU). The FCU runs the free open-source real-time operating system (RTOS) RTEMS and provides the computing and communication resources as an ELC Command and Data Handling (C&DH) system with the following major goals:

Manifested on ELC-2 was the first ELC-based payload, Materials for ISS Experiment (MISSE-7).[4] mounted on an ExPA.

ELC launch schedule

ELC-1 and ELC-2 were transported to the International Space Station by Space Shuttle Atlantis on mission STS-129 in November 2009. ELC-4 launched on mission STS-133 Discovery on 24 February 2011 and was installed on the station on 27 February. ELC-3 launched on mission STS-134 Endeavour on 16 May 2011 and was installed on the station on 18 May.

The Alpha Magnetic Spectrometer occupies the mounting location intended for ELC-5 on the ISS truss.

Launch date Mission Shuttle ELC
16 November 2009 STS-129 (ISS ULF3) Atlantis ELC-1 and ELC-2
24 February 2011 STS-133 (ISS ULF5) Discovery ELC-4
16 May 2011 STS-134 (ISS ULF6) Endeavour ELC-3

Locations and components

Location of ELCs and ESPs on the International Space Station.
Location of ELCs and ESPs on the International Space Station.

ELC-1

ExPRESS Logistics Carrier 1
ELCs 1 & 2 in the Space Shuttle Atlantis cargo bay.
Module statistics
Part ofInternational Space Station
Launch date11 (2009Z) UTC
Launch vehicleSpace Shuttle/STS-129
Berthed11 (2009) at P3 truss
Mass6,280 kg (13,840 lb)
ELC-1 in its launch configuration, note STP-H4 added Aug. 2013
ELC-1 in its launch configuration, note STP-H4 added Aug. 2013

ELC-1 is located on the P3 truss at the UCCAS-2 (nadir, earth facing) site. ELC-1 weighs approx. 13,840 lbs.[5] A FRAM is a Flight Releasable Attachment Mechanism.

ELC-2

ExPRESS Logistics Carrier 2
ELCs 1 & 2 in the Space Shuttle Atlantis cargo bay.
Module statistics
Part ofInternational Space Station
Launch date11 (2009Z) UTC
Launch vehicleSpace Shuttle/STS-129
Berthed11 (2009) at S3 truss
Mass6,100 kg (13,400 lb)
ELC-2 in its launch configuration, note changes since installation
ELC-2 in its launch configuration, note changes since installation

ELC-2 is located on the S3 truss at the PAS-1 (zenith, space facing) site, alongside AMS-2 at PAS-2. ELC-2 weighs approx. 13,400 lbs.[5]

ELC-3

ExPRESS Logistics Carrier 3
Module statistics
Part ofInternational Space Station
Launch date05 (2011Z) UTC
Launch vehicleSpace Shuttle/STS-134
Berthed05 (2011) at S3 truss
Mass6,361 kg (14,023 lb)
ELC-3 in its launch configuration, note STP-H3 removed, SCAN added
ELC-3 in its launch configuration, note STP-H3 removed, SCAN added

ELC-3 is located on the P3 truss at the UCCAS-1 (zenith, space facing) site. ELC-3 weighs 14,023 lbs.[7]

ELC-4

ExPRESS Logistics Carrier 4
In the Space Station Processing Facility at NASA's Kennedy Space Center in Florida, technicians perform the ELC-4, deck-to-keel mate.
Module statistics
Part ofInternational Space Station
Launch date02 (2011Z) UTC
Launch vehicleSpace Shuttle/STS-133
Berthed02 (2011) at S3 truss
Mass3,735 kg (8,235 lb)
ELC-4 in its launch configuration
ELC-4 in its launch configuration
ELC-4 updated FRAM ORUs
ELC-4 updated FRAM ORUs

ELC-4 is located on the S3 truss at the PAS-4 (nadir, earth facing) site, alongside ESP-3 at PAS-3. ELC-4 weighs 8,235 lbs.[13]

ISS truss components and ORUs in situ
ISS truss components and ORUs in situ

See also

References

  1. ^ Johnson Space Center (2006). EXPRESS Logistics Carrier (ELC) Development Specification (Revision B ed.). International Space Station Program. SSP 52055.
  2. ^ NASA.gov
  3. ^ "Goddard SFC ELCs Description".
  4. ^ "MISSE-7". Archived from the original on 2008-12-10.
  5. ^ a b c "EVA Checklist: STS-129 Flight Supplement" (PDF).
  6. ^ "ISS Daily Summary Report – 03/06/15". ISS On-Orbit Status Report. Retrieved 30 March 2018.
  7. ^ "STS-134 press kit cover print file 3-31-11" (PDF). Retrieved 2013-03-27.
  8. ^ "SCAN Testbed".
  9. ^ "SCaN Testbed". Spaceflightsystems.grc.nasa.gov. 2013-03-13. Archived from the original on 2012-01-11. Retrieved 2013-03-27.
  10. ^ [1] Archived April 17, 2011, at the Wayback Machine
  11. ^ "Archived copy". Archived from the original on 2011-08-07. Retrieved 2011-07-22.CS1 maint: archived copy as title (link)
  12. ^ "Robotics and Space Biology Today as Cosmonauts Look to Next Spacewalk – Space Station". blogs.nasa.gov. Retrieved 2019-05-14.
  13. ^ a b "EVA Checklist: STS-133 Flight Supplement" (PDF).
  14. ^ a b "HYV-2 Presskit" (PDF).
  15. ^ NASA.gov
General