ATK increases cable design productivity for space shuttle booster replacement by moving to a digital design process
ATK was tasked by NASA with designing the wiring harnesses for the booster rockets powering the replacement for the Space Shuttle while employing a team that is significantly smaller than that used on the now-cancelled Ares I project. ATK accomplished its mission by using E3.series to substantially increase productivity, while eliminating the need for a physical mock-up and costly test lab.
ATK is the prime contractor for a new solid rocket booster that will be used on NASA’s Space Launch System (SLS), which is intended to replace the retired Space Shuttle. The SLS is designed to take astronauts further into space than ever before and provide the cornerstone for future human space exploration efforts. NASA plans to launch the first unmanned test flight from Kennedy Space Center in 2017 and a crewed flight is scheduled for 2021. The solid rocket boosters being developed by ATK will be mounted on either side of the core stage, fire for the first two minutes of flight, and provide approximately 80% of the initial thrust needed to leave earth’s orbit. After a two-minute burn, the disposable boosters will fall into the Atlantic Ocean.
When a major change of design direction made previous work redundant, ATK met the the challenge by moving from a classical to digital process.
“When NASA came to us and said they wanted to change direction, it was an eye-opener to discover that we had made a significant investment that suddenly had little to no value. Despite the fact that the SLS boosters were based on the Ares design, the differences were large enough that they would have required starting from scratch by constructing a new prototype, new spreadsheet, and new drawings. Very little from the previous project was reusable. We were also conscious that our previous methods were very labor-intensive, so when we discovered that our next project would be equal in magnitude yet would have to be done with less manpower, we realized we needed to improve our process – and do it quickly. We decided to develop a digital approach that was less labor-intensive and would enable us to more easily adapt to change,” says Nathan Holyoak, Engineer PLM Processes for ATK.
ATK wrote a set of requirements for an electrical CAD (ECAD) system that would be both logical and functional. “It had to communicate with our MCAD system so we could quickly determine whether a cable would fit or not and how long it needed to be without mocking it up in a lab. We also insisted that the ECAD system be integrated with the MCAD system and that the results be controlled so that only authorized users could make changes and the change history would be recorded. We selected E3.series because it met all our requirements,” explains Nathan Holyoak, ATK.
ATK worked with experts from Zuken and Siemens PLM to get the two software packages working together using Zuken E3.3D Routing Bridge, which communicates using PLXML. NX librarians and checkers created over 3,000 new or modified piece parts to ensure the libraries were synchronized. Outputs from Zuken’s E3.series and Siemens’ NX are released and controlled through Siemens Teamcenter, which also handles released engineering data.
Each placement of a component in the E3.series project provided intelligence that automated many of the downstream activities that in the past had to be performed manually. E3.series ensured consistency of the entire project by keeping track of the logical design and ensuring that the physical design was consistent. The software checked the consistency of connectors, ensuring, for example, that connectors mated with each other and there were enough pins to handle each wire in an assembly. E3.series automatically tracked the components used in the project.Siemens NX calculated wire lengths and passed the information back to E3.series, which in turn calculated the voltage drop in the cables. Instead of manually producing drawings as required in the past, engineers were able to generate alternate views of the wire harnesses for formboard or cable documentation as required with very little effort.
“In the past we had a lot of people working hard. Today we have a much smaller number of people working smart, with an automated interface, and the results are impressive. The electrical engineers enter requirements and the software makes sure they have been met. If there is a problem, E3.series greatly reduces the checking time by enabling the engineer to simply click on a signal to trace its route through the design. With a virtual logical and physical model, the teams of engineers save time by not having to travel to get to the prototype lab. Instead they can just view the design on their computer screen. With the automatic checks performed by the software, people have a much higher level of confidence that everything is right, so we are saving a huge amount of time that was previously spent checking and double-checking. We talked to our suppliers and asked them how much they would charge us to produce the formboards themselves if we provided them with the electronic documentation. We have to include some extra information in the drawings, such as braid overlaps, but compared to the original cost, the savings were substantial.” – Nathan Holyoak, ATK.
Going from months to weeks [for a feasibility test] has not only made ATK more competitive, but has established us as a trusted partner of NASA. Besides these savings, we also have much more confidence that our designs are correct. Zuken has been an exceptional partner throughout this process.
Nathan HolyoakEngineer PLM Processes for ATK
In the past we had a lot of people working hard. Today we have a much smaller number of people working smart, with an automated interface, and the results are impressive.