Electrical system of the International Space Station

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International Space Station solar array wing (Expedition 17 crew, August 2008). Earth horizon and International Space Station solar panel array (Expedition 17 crew, August 2008).jpg
International Space Station solar array wing (Expedition 17 crew, August 2008).
An ISS solar panel intersecting Earth's horizon. ISS solar panel intersecting Earth's horizon.jpg
An ISS solar panel intersecting Earth's horizon.

The electrical system of the International Space Station is a critical part of the International Space Station (ISS) as it allows the operation of essential life-support systems, safe operation of the station, operation of science equipment, as well as improving crew comfort. The ISS electrical system uses solar cells to directly convert sunlight to electricity. Large numbers of cells are assembled in arrays to produce high power levels. This method of harnessing solar power is called photovoltaics.

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The process of collecting sunlight, converting it to electricity, and managing and distributing this electricity builds up excess heat that can damage spacecraft equipment. This heat must be eliminated for reliable operation of the space station in orbit. The ISS power system uses radiators to dissipate the heat away from the spacecraft. The radiators are shaded from sunlight and aligned toward the cold void of deep space.

Solar array wing

Close-up view of folded solar array. ISS P6 truss solar array - close-up (ISS014-E-10053).jpg
Close-up view of folded solar array.
Damage to the 4B wing of the P6 solar array wing found when it was redeployed after being moved to its final position on the STS-120 mission. STS120SolarPanel.jpg
Damage to the 4B wing of the P6 solar array wing found when it was redeployed after being moved to its final position on the STS-120 mission.

Each ISS solar array wing (often abbreviated "SAW") consists of two retractable "blankets" of solar cells with a mast between them. Each wing is the largest ever deployed in space, weighing over 2,400 pounds and using nearly 33,000 solar arrays, each measuring 8-cm square with 4,100 diodes. When fully extended, each is 35 metres (115 ft) in length and 12 metres (39 ft) wide. Each SAW is capable of generating nearly 31 Kilowatts (kW) of direct current power. [1] When retracted, each wing folds into a solar array blanket box just 51 centimetres (20 in) high and 4.57 metres (15.0 ft) in length. [2]

Altogether, the eight solar array wings [3] can generate about 240 kilowatts in direct sunlight, or about 84 to 120 kilowatts average power (cycling between sunlight and shade). [4]

The solar arrays normally track the Sun, with the "alpha gimbal" used as the primary rotation to follow the Sun as the space station moves around the Earth, and the "beta gimbal" used to adjust for the angle of the space station's orbit to the ecliptic. Several different tracking modes are used in operations, ranging from full Sun-tracking, to the drag-reduction mode ( night glider and Sun slicer modes), to a drag-maximization mode used to lower the altitude.[ citation needed ]

Over time, the photovoltaic cells on the wings have degraded gradually, having been designed for a 15-year service life. This is especially noticeable with the first arrays to launch, with the P6 and P4 Trusses in 2000 (STS-97) and 2006 (STS-115). [5]

STS-117 delivered the S4 truss and solar arrays in 2007.

STS-119 (ISS assembly flight 15A) delivered the S6 truss along with the fourth set of solar arrays and batteries to the station during March 2009.

To augment the oldest wings, NASA launched three pairs of large-scale versions of the ISS Roll Out Solar Array (IROSA) aboard three SpaceX Dragon 2 cargo launches from early June 2021 to early June 2023, SpaceX CRS-22, CRS-26 and CRS-28. [6] These arrays were deployed along the central part of the wings up to two thirds of its length. [7] Work to install iROSA's support brackets on the truss mast cans holding the Solar Array Wings was initiated by the crew members of Expedition 64 in late February 2021. [8] [9] After the first pair of arrays were delivered in early June, a spacewalk on 16 June by Shane Kimbrough and Thomas Pesquet of Expedition 65 to place one iROSA on the 2B power channel and mast can of the P6 truss ended early due to technical difficulties with the array's deployment. [10] [11] [12]

ISS new roll out solar array as seen from a zoom camera on the P6 Truss ISS new iROSA deployed.jpg
ISS new roll out solar array as seen from a zoom camera on the P6 Truss

The 20 June spacewalk saw the first iROSA's successful deployment and connection to the station's power system. [13] [14] [12] The 25 June spacewalk saw the astronauts successfully install and deploy the second iROSA on the 4B mast can opposite the first iROSA. [15] [12]

The next pair of panels were launched on 26 November 2022. [6] Astronauts Josh Cassada and Frank Rubio of Expedition 68 installed each one on the 3A power channel and mast can on the S4 segment, and the 4A power channel and mast can on the P4 truss segments, on 3 and 22 December 2022, respectively. [16]

The third pair of panels were launched on 5 June 2023. On 9 June, astronauts Steve Bowen and Warren Hoburg of Expedition 69 installed the fifth iROSA on the 1A power channel and mast can on the S4 truss segment. [17] [18] On 15 June, Bowen and Hoburg installed the sixth iROSA on the 1B power channel and mast can on the S6 truss segment. [19]

The last pair of iROSAs, the seventh and eighth, are planned to be installed on the 2A and 3B power channels on the P4 and S6 truss segments in 2025. [20]

Batteries

Since the station is often not in direct sunlight, it relies on rechargeable lithium-ion batteries (initially nickel-hydrogen batteries) to provide continuous power during the "eclipse" part of the orbit (35 minutes of every 90 minute orbit).

Each battery assembly, situated on the S4, P4, S6, and P6 Trusses, consists of 24 lightweight lithium-ion battery cells and associated electrical and mechanical equipment. [21] [22] Each battery assembly has a nameplate capacity of 110  Ah (396,000  C) (originally 81 Ah) and 4 kWh (14 MJ). [23] [24] [25] This power is fed to the ISS via the BCDU and DCSU respectively.

The batteries ensure that the station is never without power to sustain life-support systems and experiments. During the sunlight part of the orbit, the batteries are recharged. The nickel-hydrogen batteries and the battery charge/discharge units were manufactured by Space Systems/Loral (SS/L), [26] under contract to Boeing. [27] Ni-H2 batteries on the P6 truss were replaced in 2009 and 2010 with more Ni-H2 batteries brought by Space Shuttle missions. [25] The nickel-hydrogen batteries had a design life of 6.5 years and could exceed 38,000 charge/discharge cycles at 35% depth of discharge. They were replaced multiple times during the expected 30-year life of the station. [28] [24] Each battery measured 40 by 36 by 18 inches (102 by 91 by 46 cm) and weighed 375 pounds (170 kg). [29] [24]

From 2017 to 2021, the nickel-hydrogen batteries were replaced by lithium-ion batteries. [25] On January 6, 2017, Expedition 50 members Shane Kimbrough and Peggy Whitson began the process of converting some of the oldest batteries on the ISS to the new lithium-ion batteries. [25] Expedition 64 members Victor J. Glover and Michael S. Hopkins concluded the campaign on February 1, 2021. [30] [31] [32] [33] There are a number of differences between the two battery technologies. One difference is that the lithium-ion batteries can handle twice the charge, so only half as many lithium-ion batteries were needed during replacement. [25] [24] Also, the lithium-ion batteries are smaller than the older nickel-hydrogen batteries. [25] Although Li-ion batteries typically have shorter lifetimes than Ni-H2 batteries as they cannot sustain as many charge/discharge cycles before suffering notable degradation, the ISS Li-ion batteries have been designed for 60,000 cycles and ten years of lifetime, much longer than the original Ni-H2 batteries' design life span of 6.5 years. [25] [24]

Power management and distribution

ISS Electrical Power Distribution Electrical Power Distribution.png
ISS Electrical Power Distribution

The power management and distribution subsystem operates at a primary bus voltage set to Vmp, the peak power point of the solar arrays. As of 30 December 2005, Vmp was 160 volts DC (direct current). It can change over time as the arrays degrade from ionizing radiation. Microprocessor-controlled switches control the distribution of primary power throughout the station.[ citation needed ]

The battery charge/discharge units (BCDUs) regulate the amount of charge put into the battery. Each BCDU can regulate discharge current from two battery ORUs (each with 38 series-connected Ni-H2 cells), and can provide up to 6.6 kW to the Space Station. During insolation, the BCDU provides charge current to the batteries and controls the amount of battery overcharge. Each day, the BCDU and batteries undergo sixteen charge/discharge cycles. The Space Station has 24 BCDUs, each weighing 100 kg. [26] The BCDUs are provided by SS/L [26]

Sequential shunt unit (SSU)

Eighty-two separate solar array strings feed a sequential shunt unit (SSU) that provides coarse voltage regulation at the desired Vmp. The SSU applies a "dummy" (resistive) load that increases as the station's load decreases (and vice versa) so the array operates at a constant voltage and load. [34] The SSUs are provided by SS/L. [26]

DC-to-DC conversion

DC-to-DC converter units supply the secondary power system at a constant 124.5 volts DC, allowing the primary bus voltage to track the peak power point of the solar arrays.

Thermal control

The thermal control system regulates the temperature of the main power distribution electronics and the batteries and associated control electronics. Details on this subsystem can be found in the article External Active Thermal Control System.

Station to shuttle power transfer system

From 2007 the Station-to-Shuttle Power Transfer System (SSPTS; pronounced spits) allowed a docked Space Shuttle to make use of power provided by the International Space Station's solar arrays. Use of this system reduced usage of a shuttle's on-board power-generating fuel cells, allowing it to stay docked to the space station for an additional four days. [35]

SSPTS was a shuttle upgrade that replaced the Assembly Power Converter Unit (APCU) with a new device called the Power Transfer Unit (PTU). The APCU had the capacity to convert shuttle 28 VDC main bus power to 124 VDC compatible with ISS's 120 VDC power system. This was used in the initial construction of the space station to augment the power available from the Russian Zvezda service module. The PTU adds to this the capability to convert the 120 VDC supplied by the ISS to the orbiter's 28 VDC main bus power. It is capable of transferring up to 8 kW of power from the space station to the orbiter. With this upgrade both the shuttle and the ISS were able to use each other's power systems when needed, though the ISS never again required the use of an orbiter's power systems.[ citation needed ]

In December 2006, during mission STS-116, PMA-2 (then at the forward end of the Destiny module) was rewired to allow for the use of the SSPTS. [36] The first mission to make actual use of the system was STS-118 with Space Shuttle Endeavour. [37]

Only Discovery and Endeavour were equipped with the SSPTS. Atlantis was the only surviving shuttle not equipped with the SSPTS, so it could only go on shorter length missions than the rest of the fleet. [38]

Related Research Articles

<span class="mw-page-title-main">STS-92</span> 2000 American crewed spaceflight to the ISS

STS-92 was a Space Shuttle mission to the International Space Station (ISS) flown by Space Shuttle Discovery. STS-92 marked the 100th mission of the Space Shuttle. It was launched from Kennedy Space Center, Florida, 11 October 2000.

<span class="mw-page-title-main">STS-97</span> 2000 American crewed spaceflight to the ISS

STS-97 was a Space Shuttle mission to the International Space Station (ISS) flown by Space Shuttle Endeavour. The crew installed the first set of solar arrays to the ISS, prepared a docking port for arrival of the Destiny Laboratory Module, and delivered supplies for the station's crew. It was the last human spaceflight of the 20th century.

<span class="mw-page-title-main">STS-115</span> 2006 American crewed spaceflight to the ISS

STS-115 was a Space Shuttle mission to the International Space Station (ISS) flown by Space ShuttleAtlantis. It was the first assembly mission to the ISS after the Columbia disaster, following the two successful Return to Flight missions, STS-114 and STS-121. STS-115 launched from LC-39B at the Kennedy Space Center on September 9, 2006, at 11:14:55 EDT.

<span class="mw-page-title-main">Shane Kimbrough</span> American astronaut

Robert Shane Kimbrough is a retired United States Army officer and NASA astronaut. He was part of the first group of candidates selected for NASA astronaut training following the Space Shuttle Columbia disaster. Kimbrough is a veteran of three spaceflights, the first being a Space Shuttle flight, and the second being a six-month mission to the ISS on board a Russian Soyuz craft. He was the commander of the International Space Station for Expedition 50, and returned to Earth in April 2017. He is married to the former Robbie Lynn Nickels.

<span class="mw-page-title-main">STS-116</span> 2006 American crewed spaceflight to the ISS

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<span class="mw-page-title-main">STS-117</span> 2007 American crewed spaceflight to the ISS

STS-117 was a Space Shuttle mission flown by Space Shuttle Atlantis, launched from pad 39A of the Kennedy Space Center on June 8, 2007. Atlantis lifted off from the launch pad at 19:38 EDT. Damage from a hail storm on February 26, 2007, had previously caused the launch to be postponed from an originally-planned launch date of March 15, 2007. The launch of STS-117 marked the 250th orbital human spaceflight. It was also the heaviest flight of the Space Shuttle.

<span class="mw-page-title-main">STS-118</span> 2007 American crewed spaceflight to the ISS

STS-118 was a Space Shuttle mission to the International Space Station (ISS) flown by the orbiter Endeavour. STS-118 lifted off on August 8, 2007, from launch pad 39A at Kennedy Space Center (KSC), Florida and landed at the Shuttle Landing Facility at KSC on August 21, 2007.

<span class="mw-page-title-main">STS-119</span> 2009 American crewed spaceflight to the ISS

STS-119 was a Space Shuttle mission to the International Space Station (ISS) which was flown by Space Shuttle Discovery during March 2009. It delivered and assembled the fourth starboard Integrated Truss Segment (S6), and the fourth set of solar arrays and batteries to the station. The launch took place on March 15, 2009, at 19:43 EDT. Discovery successfully landed on March 28, 2009, at 15:13 pm EDT.

<span class="mw-page-title-main">STS-120</span> 2007 American crewed spaceflight to the ISS

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<span class="mw-page-title-main">STS-127</span> 2009 American crewed spaceflight to the ISS

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<span class="mw-page-title-main">Integrated Truss Structure</span> Part of the International Space Station; sequence of connected trusses

The Integrated Truss Structure (ITS) of the International Space Station (ISS) consists of a linear arranged sequence of connected trusses on which various unpressurized components are mounted such as logistics carriers, radiators, solar arrays, and other equipment. It supplies the ISS with a bus architecture. It is approximately 110 meters long and is made from aluminium and stainless steel.

<span class="mw-page-title-main">Pressurized Mating Adapter</span> Spacecraft docking adapter

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<span class="mw-page-title-main">Assembly of the International Space Station</span> Process of assembling the International Space Station

The process of assembling the International Space Station (ISS) has been under way since the 1990s. Zarya, the first ISS module, was launched by a Proton rocket on 20 November 1998. The STS-88 Space Shuttle mission followed two weeks after Zarya was launched, bringing Unity, the first of three node modules, and connecting it to Zarya. This bare 2-module core of the ISS remained uncrewed for the next one and a half years, until in July 2000 the Russian module Zvezda was launched by a Proton rocket, allowing a maximum crew of three astronauts or cosmonauts to be on the ISS permanently.

<span class="mw-page-title-main">Maintenance of the International Space Station</span> Servicing of the crewed low-Earth orbital research platform

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<span class="mw-page-title-main">US Orbital Segment</span> US components of the International Space Station

The US Orbital Segment (USOS) is the name given to the components of the International Space Station (ISS) constructed and operated by the United States National Aeronautics and Space Administration (NASA), European Space Agency (ESA), Canadian Space Agency (CSA) and Japan Aerospace Exploration Agency (JAXA). The segment consists of eleven pressurized components and various external elements, almost all of which were delivered by the Space Shuttle.

<span class="mw-page-title-main">Roll Out Solar Array</span> Spacecraft solar panels

The Roll Out Solar Array (ROSA) and its larger version ISS Roll Out Solar Array (iROSA) are lightweight, flexible power sources for spacecraft designed and developed by Redwire.

<span class="mw-page-title-main">Expedition 63</span> Long-duration mission to the International Space Station

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<span class="mw-page-title-main">Expedition 65</span> 65th Long-duration mission to the International Space Station

Expedition 65 was the 65th long duration expedition to the International Space Station. The mission began on 17 April 2021 with the departure of Soyuz MS-17 and was initially commanded by NASA astronaut Shannon Walker serving as the third female ISS commander, who launched in November 2020 aboard SpaceX Crew-1 alongside NASA astronauts Michael S. Hopkins and Victor J. Glover, as well as JAXA astronaut Soichi Noguchi. They were joined by the crew of Soyuz MS-18, which is made up of Russian cosmonauts Oleg Novitsky and Pyotr Dubrov, as well as NASA astronaut Mark Vande Hei.

<span class="mw-page-title-main">Expedition 64</span> Long-duration mission to the International Space Station

Expedition 64 was the 64th long-duration expedition to the International Space Station (ISS) that began on 21 October 2020 with the undocking and departure of Soyuz MS-16. The expedition started with the three crew members who launched onboard Soyuz MS-17 and reached its full complement with the arrival of SpaceX Crew-1, the first operational flight of NASA's Commercial Crew Program (CCP). As Crew-1 consists of a crew of four instead of three like the Soyuz, Expedition 64 marks the beginning of operations for crews of seven on the ISS. In the final week of the mission, Soyuz MS-18 and its three person crew joined the mission. The expedition ended on 17 April 2021 with the departure of Soyuz MS-17.

References

  1. ↑ "Spread Your Wings, It's Time to Fly". NASA. July 26, 2006.
  2. ↑ "STS-97: Photovoltaic array assembly". NASA. November 9, 2000. Archived from the original on January 23, 2001.
  3. ↑ "International Space Station – Solar Power". Boeing.
  4. ↑ Wright, Jerry. "Solar Arrays". NASA. Retrieved 2016-03-23.
  5. ↑ "NASA.gov". Archived from the original on 2018-12-29. Retrieved 2021-05-26.
  6. 1 2 Clark, Stephen (26 November 2022). "SpaceX launches Dragon cargo ship to deliver new solar arrays to space station – Spaceflight Now". Spaceflight Now – The leading source for online space news. Retrieved 28 November 2022.
  7. ↑ "Current and Future Operations and Challenges with International Space Station" (PDF). ISS Program Office. NASA. 15 Oct 2020. Retrieved 2 May 2021.
  8. ↑ "Expedition 64 Information Page". Spacefacts.de. 10 May 2021. Retrieved 17 June 2021.
  9. ↑ Garcia, Mark (11 January 2021). "New Solar Arrays to Power NASA's International Space Station Research". NASA. Archived from the original on 24 May 2023. Retrieved 26 April 2021.PD-icon.svg This article incorporates text from this source, which is in the public domain .
  10. ↑ Garcia, Mark (16 June 2021). "Spacewalk to Install First New Solar Array Concluded". NASA. Retrieved 17 June 2021.PD-icon.svg This article incorporates text from this source, which is in the public domain .
  11. ↑ "Hardware, Spacesuit Difficulties Stall Ambitious ISS Spacewalk". Aviation Week. Informa Markets. 17 June 2021. Retrieved 17 June 2021.
  12. 1 2 3 "Expedition 65 Information Page". Spacefacts.de. 17 June 2021. Retrieved 17 June 2021.
  13. ↑ Guardian, AP and AFP staff (20 June 2021). "ISS astronauts complete six-hour spacewalk to install solar panels". The Guardian . Guardian News and Media Ltd. Retrieved 26 June 2021.
  14. ↑ Pearlman, Robert Z. (20 June 2021). "Astronauts on spacewalk deploy first roll-out solar array to boost power for station". Space.com. Future US Inc. Retrieved 26 June 2021.
  15. ↑ Pearlman, Robert Z. (25 June 2021). "Spacewalking astronauts deploy second new solar array for space station". Space.com. Future US Inc. Retrieved 26 June 2021.
  16. ↑ Pearlman, Robert Z. (22 December 2022). "NASA astronauts unfurl 4th roll-out solar array on spacewalk outside space station". Space.com. Retrieved 23 December 2022.
  17. ↑ Garcia, Mark (2023-06-09). "NASA Astronauts Begin Spacewalk to Install Solar Array". blogs.nasa.gov. Retrieved 2023-06-10.
  18. ↑ Garcia, Mark (2023-06-09). "NASA Spacewalkers Complete Solar Array Installation". blogs.nasa.gov. Retrieved 2023-06-10.
  19. ↑ Clark, Stephen (June 9, 2023). "Astronauts install new roll-out solar array outside International Space Station – Spaceflight Now". Spaceflight Now. Retrieved June 10, 2023.
  20. ↑ Davenport, Justin (June 15, 2023). "ISS finishes initial iROSA upgrade with two EVAs this month". NASASpaceFlight.com. Retrieved June 18, 2023.
  21. ↑ Garcia, Mark (6 January 2017). "Astronauts complete first of two power upgrade spacewalks". NASA. Retrieved 28 February 2021.PD-icon.svg This article incorporates text from this source, which is in the public domain .
  22. ↑ Schwanbeck, Eugene; Dalton, Penni (16 December 2019). "International Space Station Lithium-ion Batteries for Primary Electric Power System". 2019 European Space Power Conference (ESPC). IEEE. p. 1. doi:10.1109/ESPC.2019.8932009. ISBN   978-1-7281-2126-0. S2CID   209382968 . Retrieved 5 March 2021.
  23. ↑ "International Space Station Nickel-Hydrogen Batteries Approached 3-Year On-Orbit Mark". NASA. Archived from the original on March 7, 2005. Retrieved September 14, 2007.
  24. 1 2 3 4 5 Dalton, Penni; Bowens, Ebony; North, Tim; Balcer, Sonia (November 19, 2019). "International Space Station Lithium-ion Battery Status" (PDF). NASA. Retrieved March 5, 2021.
  25. 1 2 3 4 5 6 7 "EVA-39: Spacewalkers complete the upgrading of ISS batteries". January 13, 2017. Retrieved March 5, 2021.
  26. 1 2 3 4 "International Space Station" (PDF). Space Systems Loral. February 1998. Archived from the original (PDF) on December 27, 2014.
  27. ↑ "Space Systems/Loral awarded $103 million contract to build critical power systems for the International Space Station" (Press release). Loral. July 8, 2003. Archived from the original on September 28, 2007.
  28. ↑ "Nickel-Hydrogen Battery Cell Life for International Space Station". NASA. Archived from the original on 2009-08-25.
  29. ↑ "STS-97 Payload: Photovoltaic Array Assembly (PVAA)". NASA. Archived from the original on January 23, 2001. Retrieved September 14, 2007.
  30. ↑ Garcia, Mark (1 February 2021). "Spacewalkers complete multi-year effort to upgrade space station batteries". NASA. Retrieved 5 March 2021.PD-icon.svg This article incorporates text from this source, which is in the public domain .
  31. ↑ Garcia, Mark (1 February 2021). "Spacewalkers wrap up battery work and camera installations". NASA. Retrieved 5 March 2021.PD-icon.svg This article incorporates text from this source, which is in the public domain .
  32. ↑ Gohd, Chelsea (February 1, 2021). "Spacewalking astronauts complete a space station battery upgrade years in the making". Space.com. Retrieved March 5, 2021.
  33. ↑ Garcia, Mark (27 January 2021). "Spacewalk wraps up with upgrades on European lab module". NASA. Retrieved 28 February 2021.PD-icon.svg This article incorporates text from this source, which is in the public domain .
  34. ↑ "Options Studied for Managing Space Station Solar Array Electrical Hazards for Sequential Shunt Unit Replacement". NASA. Archived from the original on 2006-10-08.
  35. ↑ "STS-118 crew interview, Station to Shuttle Power System". space.com.
  36. ↑ "Aft flight deck payloads switch list for handover". Ascent Checklist STS-116 (PDF). Mission Operations Directorate Flight Design and Dynamics Division. October 19, 2006. p. 174. Archived from the original (PDF) on May 24, 2011. Retrieved April 2, 2009.
  37. ↑ "STS-118 MCC Status Report #05". NASA. August 10, 2007. Archived from the original on October 19, 2007. Retrieved April 2, 2009.
  38. ↑ Gebhardt, Chris (November 16, 2009). "Fuel Cell 2 issue cleared – Atlantis in perfect launch". NASAspaceflight.com.
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