The final photo of the PPE Power and Propulsion Module production for the Gateway Space Station that we published in our series was from March of this year. Since then, outer plates have been attached to the central composite cylinder with two vertical and four horizontal plates. This is how the module got its basic cuboid shape. At detailed view you can also see the handle for hanging the solar battery panel in the left plate. In parallel with assembly, teams at Maxar Technologies in Palo Alto, Calif., are putting the module through a series of tests to verify the integrity of the hardware for future space flight. Due to the unreadiness of the Starship lunar lander, a recommendation for changes to the Artemis campaign could be made in the first months of 2024. The Artemis 3 mission, which is designed to send astronauts to the surface of the Moon for the first time since the Apollo program, may change to a mission without connecting to a target body in lunar orbit. A flight to the Gateway station, consisting of PPE and HALO modules, is also a discussed option. It depends on the timely readiness of both modules.
Artemis 3
This December 20, 2022 photo shows the hydrogen tank for Artemis 3 being moved into Cell A (far left). There is a VAC welder in the distance between the tank and cell A. Of note is the unfinished oxygen tank for Artemis 3 in the welder.
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However, even the preparation of the Artemis 3 mission does not avoid delays. The production of both tanks for the central stage of the SLS launch vehicle at the Michoud Assembly Facility in New Orleans is currently experiencing the biggest slippage.
The liquid hydrogen tank was originally manufactured in 2016 for Artemis 1. However, an analysis of the welds found their strength level below the specified design strength. In the following years, a new filler material was applied to the welds. Last year, the strength of the welds was mechanically tested. After the tank resistance tests, a standard X-ray analysis of the welds was performed.
However, due to the unusual history and repair of the welds, it was decided to perform an extraordinary additional scan of the tank in cell A of building 110. The tank was inserted into cell A in December 2022. The surface height of the welds was documented in detail by the scanner. The data from the scanner will be used in later activities, for example during the robotic application of foam insulation to the outer surface of the tank.
Analysis of the scans was only recently completed. The results turned out well and the tank proved airworthy. The next step in preparation will be to wash the tank in Cell E. For comparison, the hydrogen tank for Artemis 2 was inserted into Cell E in July 2020. The interior of the tank will be washed and cleaned in preparation for fitting flight sensors such as fuel level detectors.
After the sensors are installed, the tank will be moved to Cell P in Building 131 to be primed. After moving to building 103, the tank will be equipped with additional sensors and preparation for the installation of pipes will also take place. Then the tank awaits transfer to cell N in building 131 for the application of thermal insulation foam.
Unfinished central stage oxygen tank for Artemis 3 in the VAC welder (right section). The photo was taken on 15 September 2023 during the transfer of the RS-25 engine for mounting on the center stage for Artemis 2.
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However, the production of the liquid oxygen tank suffered an even bigger slide. In the summer and fall of 2022, the upper dome and two cylindrical parts of the tank were welded together in the VAC (Vertical Assembly Center) welding facility in building 110. Since then, the delivery of the last part, which is the lower dome, has been awaited.
An unspecified welding problem is delaying production of the lower dome. The dome is produced in a Circumferential Dome Weld Tool (CDWT). It was welded from twelve segments. The ring and end piece are usually welded last.
Boeing is working on corrective measures and is said to be well on its way to completing the dome welding. Meanwhile, welding of the upper dome for the oxygen tank for Artemis 4 was completed in July 2023 in the CDWT tool.
This July 27, 2022 photo shows the transfer of the completed upper dome of the Artemis 3 oxygen tank onto a transport trolley in Building 103. In the left part of the photo, the lower dome is under construction.
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In comparison, welding of the oxygen tank for Artemis 2 began in the last quarter of 2018 and was completed in February 2019.
When the welding of the oxygen tank is complete, it will undergo a proof test in building 110 and an X-ray inspection in building 103. Then, in the washing cell E of building 110, the inner and outer walls of the tank will be cleaned with water. After subsequent drying, the tank will be moved to cell P of building 131 to be primed. But only after the hydrogen tank goes through the same process. After injection, the oxygen tank will be moved back to Building 103, where it will be equipped with flight sensors. Once this activity is complete, the tank will be returned to Building 131, this time to Cell N for the application of thermal insulation foam.
Other parts for the central stage have already moved to the stage of fitting out internal systems. The top edge and intertank have completed thermal insulation. Cable harnesses and mounts for flight computers and other equipment are installed on their inner walls.
Safety Feature – Completed Orion Rescue System escape engine for Artemis 3
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The engine section was transported from MAF to the SSPF building at Kennedy Space Center in December 2022 to be outfitted with internal systems. Installation of propulsion system piping and wiring harnesses is now underway. The engine section will be connected to the central stage only in the VAB hall.
Boeing’s plan is to complete the central stage in late 2024 or early 2025. However, this is completely unrealistic, and the recommendation for changes in the Artemis campaign, due in the first months of 2024, should reflect this year’s slippage in the preparation of both tanks of the central stage .
The Artemis 2 mission crew visited the Airbus Space Clean Room in Bremen, Germany in September 2023 and toured the European Service Module for Artemis 3
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The ESM-3 European Service Module for Orion is being completed at Airbus Space’s production facility in Bremen, Germany. It is scheduled to be delivered to the Kennedy Space Center in the O&C building at the end of this year. The CMA adapter is already waiting here, which should be connected to the ESM-3 at the beginning of next year.
The crew module now awaits the installation of the first elements of the avionics, the carbon dioxide removal system and other components of the life support system. We featured photos of the crew module and CMA adapter in the last installment.
Artemis 4
In the last installment, we quoted ULA CEO Tory Bruno as saying ULA’s continued ability to produce the next ICPS upper stage. In his article on NASASpaceflight, editor Philip Sloss addressed this possibility as an opportunity to shorten the interval between the Artemis 3 and Artemis 4 missions. NASA still has the option to buy another ICPS stage. The requirements for mitigating the risks of the last mission of the Delta IV Heavy rocket with the NROL-70 payload include maintaining the production line of the Delta rockets that ICPS uses until the launch of the NROL-70. The NROL-70 mission is planned for the 1st quarter of next year.
A July 11, 2023, photo of the MAF factory hallway shows parts of the Artemis 4 oxygen tank being assembled – the top dome added to the two cylinders. In the background, the unfinished and shelved lower dome of the Artemis 3 oxygen tank blocks the use of the VAC welder for the central stage tanks for Artemis 4 as well as for the qualification prototype of the new EUS upper stage hydrogen tank, intended for ground structural tests.
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However, NASA sent an email statement to NASASpaceflight on September 19 saying that it does not plan to purchase hardware for a fourth flight of the SLS Block 1 configuration. Philip Sloss concludes the article by saying that NASA and Congress still have several months to consider this option.
With such a solution, the question of transporting the I-Hab module to the Gateway space station nucleus arises. According to a usually well-informed debater with the nickname woods170 groups at NASA are still working on the possibility of using a tractor to deliver other modules, which would be built on the basis of the Cygnus cargo spacecraft service module.
A similar solution was planned for the transportation of the HALO module before it was decided to launch it together with the PPE module. The main difference between the standard service module for Cygnus and the tractor originally designed for HALO was that the tractor could be disconnected from HALO. In his commentary, Woods170 states that the idea of having a modified service section of the Cygnus as a tractor was never rejected by the working groups at NASA.
Sources of information
https://twitter.com/
https://www.nasaspaceflight.com/
https://www.nasaspaceflight.com/
https://forum.nasaspaceflight.com/
Image Sources:
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2023-10-19 22:12:21
#Gateway #October
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