ISS spreads its wings

by Chris Bergin

NASA has successfully deployed the two solar arrays from the newly attached P3/P4 integrated truss segment, spreading out over 240 feet – as the International Space Station expands for the first time since late 2002.

In a morning of spectacular images beamed back to Earth via NASA TV, the golden arrays stretched out in stages, ready to provide around double the extra power to the expanding space station.

**L2 STS-115 Coverage: ALL related handbooks, from Final Flight Plan to Robotics to EVA Presentations (620mb of 115 presentations downloadable) NOW INCLUDING:  STS-115 Rendezvous Handbook**.

**STS-115: LIVE COUNTDOWN AND LAUNCH Update Page** – **Flight Day 2**  **Flight Day 3** **Flight Day 4 ** **Flight Day 5** **Flight Day 6** **Flight Day 7 – LIVE**

Refer to live update thread for up to the second updates.

STS-115: Full EVA Mission Overview (326 pages, 56 meg) STS-116: EVA Outline and Checklist (80meg – 433 pages). STS-116 Full Flight Plan – all available to download on L2.

‘The International Space Station has a new pair of wings,’ said NASA TV and PAO Kyle Herring, as the outpost showed off its new configuration at around 8:40am EDT.

Troubleshooting with software issues delayed the deployment until this morning. However, once the initial stages began, the arrays behaved as planned.

First, the port and starboard array was deployed by one bay, to release the tension built up from being in storage. Then they were spread out to 50 percent of their full length, holding for 30 minutes to prevent ‘stiction’ issues.

Once the station had corrected it attitude to aid the deployment, the arrays spread out to full length, showing off their golden panels, high above the Earth below.

It’s been a long road for the new addition to the station. From July 1999 to October 2000, Boeing and Marshall Space Flight Center conducted structural testing on a P3/P4 test article. The testing verified P3/P4 would perform well with launch and on-orbit structural loads during its 15-year lifespan.

A test, called the modal survey test, induced vibrations into the structure with mechanical shakers, a technical way of saying they hit it with a hammer, while various accelerometers measured the results. The more complex and lengthier testing, called the static structural test, simulated space shuttle docking loads as well as other launch and on-orbit events.

This test required a number of hydraulic actuators to be attached to various locations on the element as they input actual structural loads, by either pulling or pushing on the aluminum structure to measure how the element responded.

‘We were trying to validate whether the analytical models correctly predicted the vibration and structural responses throughout the structure to specific inputs,’ said Steve Ernst, the Boeing element manager for the P3/P4 test article and currently manager of the Boeing Huntsville International Space Station Projects Office,’ to the MSFC internal magazine Marshall Star.

‘We put the equipment through a qualification level, which was above the expected flight loads.’

With one more EVA to go, along with testing by the crew on the ISS, so far the new addition has been installed to plan, bar software issues and the occasional bolt that was lost during the spacewalks.

However, the pleasure in seeing the section spread its wings today will have been far-reaching, all the way back to those that worked on it during the early days back on Earth.

‘As a test engineer, there is nothing as rewarding as seeing hardware you were responsible for go fly,’ said Ward Overton, a Marshall engineer who tested P3/P4 and currently works on the External Tank Project.

‘The former Static Structural Test Branch in the Engineering Directorate exceeded expectations in completing this testing. Not a lot of folks can say they worked with hardware that’s on the station. I’m proud our team can say we did.’

Meanwhile, Lockheed Martin – who were also involved with the payload Atlantis took uphill to the ISS – spoke of their joy from seeing the solar arrays come to life.

‘It is a testament to the professionalism of the STS-115 crew and the mission support team that they made this difficult ISS construction project look easy, and the deployment of the new arrays was a sight to behold,’ said Brad Haddock, Lockheed Martin ISS program director.

‘To see our arrays producing electricity is wonderfully satisfying, and we’re confident that this addition will further harness solar energy for the Space Station and provide the power required for many years to come.’ 

(Video section is FREE, but you need to sign up as a member of the forum to enter the video section of the site. We only use your e-mail to send you your password. It will not be used for spam etc.)

** Job Opportunities** 

              LIVE UPDATE PAGES


Related Articles