March 1, 2011
Student Night
5:50 – 6:30 Social Hour
6:30 – 7:30 Dinner
7:30 – Speaker: John Alred
Materials Applications – International Space Station
Meeting Location:
U of H Hilton school of Hotel and Restaurant management
Central Campus (Driving Directions)
Room 261C
Directions to this building from
I-45 South
(downtown)
- exit Spur 5 South
- at light turn right on University Dr.
- cross Calhoun and enter campus at Entrance 1
- after the stop sign and info booth, the Hilton will be on the left
Pricing (for this meeting only):
- $36 Members registered and paid online
- $46 All others
- Students Free
Price includes dinner and garage parking.
Topic
The International Space Station (ISS) is of such complexity and scale that there have been numerous issues addressed regarding materials; from design to manufacturing, test, launch, assembly on-orbit, and operations. A selection of lessons learned and anomalies from the ISS materials perspective are provided.
One on-orbit anomaly of extreme interest is the Solar Alpha Rotary Joint (SARJ). The SARJ is a single-axis pointing mechanism used to orient the solar power generating arrays relative to the sun for the International Space Station (ISS). Approximately 83 days after its on-orbit installation, one of the two SARJ mechanisms aboard the ISS began to exhibit high drive motor current draw. Increased structural vibrations near the joint were also observed. Subsequent inspections via Extravehicular Activity (EVA) discovered that the nitrided case hardened steel bearing race on the outboard side of the joint had extensive damage to one of its three rolling surfaces. A far-reaching investigation of the anomaly was undertaken. The investigation included metallurgical inspections, coupon tests, traction kinematics tests, detailed bearing measurements, and thermal and structural analyses. The results of the investigation showed that anomaly had most probably been caused by high bearing edge stresses that resulted from inadequate lubrication of the rolling contact. To mitigate the impact of the damage astronauts cleaned and lubricated the race ring surface with grease. This corrective action led to significantly improved performance of the mechanism both in terms of drive motor current and induced structural vibration.
The presentation will conclude with a summary of challenges expected in the completion of the ISS program. Finally, a quick look at technological challenges in material sciences to be studied by NASA in the future will be addressed.
Bio – John Alred
While born in North Hollywood, California, John grew up in the country side near Little Rock, Arkansas. He attended the University of Central Arkansas where he received Bachelor of Science degrees in Physics and Mathematics. He continued on in Physics receiving a M.S., followed by a Ph.D, at Baylor University.
John was a summer intern at the NASA Johnson Space Center in the Engineering Analysis Division where he supported the Space Shuttle Program. After receiving his last degree, he joined JSC to continue to support the Space Shuttle Program as welll as very early Space Station development studies. He became part of the JSC Advanced Programs Office where he led lunar and Mars surface studies as well as mission architecture studies for NASA’s Office of Exploration. Leaving NASA, he joined the Universities Space Research Association as Director of the NASA Advanced Design Program, managing 44 universities linking engineering capstone design courses to active NASA programs. After the demise of that program, he became Director of Advanced Programs at Eagle Engineering, where he led Lunar/Mars studies as well as assorted advanced mission planning for NASA and aerospace industry customers. When this company went out of business, John became a visiting professor at Texas A&M University in the Aerospace, Mechanical, and Nuclear Engineering Departments. He also was an Adjunct Professor at the University of Houston Mechanical Engineering Department as well as the UH Sasakawa Institute for Space Architecture. He then began a series of aerospace industry positions with Lockheed-Martin/Denver, Hernandez Engineering, Lockheed-Martin/Houston, and finally The Boeing Company where he joined the Space Environments Group as Plasma Team Lead as well as External Contamination analyst. He returned to NASA JSC in 2006 as the Lead of the Non-Metallic Materials Team in the Materials & Processes Branch of the Structural Engineering Division. In that role, John is also the Deputy Manager for NASA JSC Space Environments and the Deputy Manager for ISS Materials and Processes.
Lastly, he is married and the proud father of three sons attending the University of Houston.