Two astronauts aboard the International Space Station (ISS) are expected to make a spacewalk to begin the process of increasing the station’s electric power generation output.
The spacecraft, US EVA-71, will be led by NASA astronauts Kate Rubins and Victor Glover, who officially launched at 06:12 EST (11:12 UTC).
Solar supply background:
The ISS is equipped with eight Solar Array Wings (SAWs), each of which is designed to produce approximately 30 kilowatts (kW) of power, for a total of approximately 250kW across the eight arrays.
The oldest array, connected to the P6 outfit, was launched in 2000 on the STS-97 mission of the Shuttle Endeavor, with the additional arrays launched in 2006, 2007, and 2009 on board STS-115 and STS-117 Atlantis missions and Discovery STS-119 missions, respectively.
As a result of pollution – it was expected – the power generation plants now only produce around 160kW of power. At the same time, users of the Station, including the recently added Nanoracks Bishop aircraft and the outdoor European Bartolomeo platform, need more power than originally anticipated. at the time of designing the outpost.
Although the Station’s solar arrays were originally designed to be completely removed and reinstalled through the Space Shuttle, the retirement of that vehicle prompted the ISS program to find an innovative solution to increase the amount of power available.
As a result, the ISS Power Augmentation (IPA) program was born. The plan calls for the addition of six additional solar arrays to the ISS to boost power generation and bring it back to original levels.
In particular, six new Solar Roll Out ISS (IROSA) Arrays will be added. The IROSAn are a new type of array technology, which is different from the original arrays at the Station which are folded and used in a box-like manner.
Developed by Deployable Space Systems in California, the IROSAs distribute in a mat-like manner from the inside of a cylinder canister.
Its solar cells are mounted on a thin, flexible blanket rather than traditional rigid panels, and it features a composite finish that adds durability and allows for use without the use of motors or multi-purpose machines. -fold.
This allows the high altitudes to be stored tightly – which is important with the current launch options for the Station program.
The solar cells themselves are about 30% efficient, compared to the efficiency of 14% of the original solar cells. This allows the IROSAs to generate about the same amount of power as the original arrays, even though they are only half their size.
Location of the new IROSAs over the existing Station solar arrays. (Credit: NASA / Boeing)
The IROSAs will be deployed over six of the Station’s solar arrays. While the IROSAs will partially overshadow the existing realms, the original arrays will continue to generate power along with the IROSAs.
Installing the IROSAs over the top of the existing heights allows them to use the existing solar tracking motors – Beta Gimbal Assembly – of the current heights and allows all IROSAs to be connected to the electrical system that the conventional arrays use to increase their power.
Each IROSA emits 20kW of additional power, for a total of 120kW over the six arrays. The uncovered allowances of the original heights will continue to generate 95kW, making up a total of 215kW of power available to the Station, close to its original level.
This is an increase of almost a third compared to the conventional 160kW of available power. When combined with the recent effort to replace the Station’s batteries with new Lithium-Ion units, this will ensure that the ISS has sufficient power to support the applications. which continues to grow throughout the rest of his life.
A sub-scale version of the IROSA was successfully tested on Station in 2017, and the technology is already planned for use on the Power and Devolution (PPE) element of the Lunar Gate, as well as the Human Space System (HLS) ) at Dynetics. , for the Artemis Moon program.
The six IROSAs will be launched two simultaneously on a portfolio within the stock SpaceX Cargo Dragon 2 starting with the CRS-22 flight in June 2020. The new spacecraft will be installed through paths.
The “mod kit” to be built and added to Mast Canister Assemblies. These folders will serve as connecting platforms for the new arrays. (Credit: NASA)
EVA Methods:
The IROSAs will be structurally added to the base of the existing Mast Canister Assemblies, where the malls were customary at the time of launch and which are now “centers”.
However, since the IROSAs were never expected to be added to the ISS, there is currently no structure for their deployment.
Building this will be the goal of today’s spaceflight.
A so-called “mod kit” will be installed in the Mast Canister Assembly, which consists of several layers that will be connected together to create a structural framework for the future installation of the IROSAs.
The mod equipment is physically connected to the Canister Mast Assembly using existing connection points from unneeded ground handling fixtures and removable robotic pins.
The goal of today’s activity is to complete the construction of the kit mode on the 2B Mast Canister Assembly and begin the construction of the kit mode on the 4B Mast Canister Assembly – both of which are mounted on P6 uniforms. oldest solar station.
Where today’s work is on arrays 2B and 4B on the P6 outfit. (Credit: NASA)
The first task for the space walkers after translating out to the P6 workstation, carrying very large work bags with them, is to build an A-frame structure called the high brake , which will be mounted to the center of the Canister Mast 2B. Assembly.
The lower left strut and left middle strut are then connected between the upper brake and the left side of the Canister Mast Assembly. A lower right strut and a right middle strut will be inserted on the opposite side.
This will complete the 2B mod installation.
The upper brake is then lifted and attached to the Assembly 4B Mast Canister, as will its lower strut.
This is where the spacewalk is expected to end due to lack of time; however, if both are ahead of the planned timeline, build the 4B mod kitchen will continue.
If the pre-spacewalk plan is followed, the 4B Mast Canister Assembly mod device will be completed on a future spacewalk, and the pair will go back inside the Quest airfield.
(Advanced image: NASA astronaut Scott Parazynski on the arm of the Boom Orbiter Sensor System while repairing an active solar array outside the Station in November 2007. Credit: NASA)