On March 24, 2009, at 7:30 a.m. CDT, the crew aboard Space Shuttle Discovery and the International Space Station (ISS) were preparing for the upcoming undocking scheduled for the following day. This marked the penultimate day of the STS-119 mission, a pivotal operation in the assembly and enhancement of the ISS.
Mission Overview
STS-119, launched on March 15, 2009, was the 28th mission to the ISS and the 36th flight of Space Shuttle Discovery. The primary objectives were to deliver and install the S6 truss segment and the fourth set of solar arrays and batteries, completing the ISS's power system and structural backbone. The mission also aimed to replace a failed unit in the station's water recovery system, ensuring the continued sustainability of the crew's water supply. The crew consisted of Commander Lee Archambault, Pilot Tony Antonelli, Mission Specialists Richard Arnold, Joseph Acaba, John Phillips, Steve Swanson, and Japan Aerospace Exploration Agency (JAXA) astronaut Koichi Wakata. Wakata joined the ISS crew, replacing Flight Engineer Sandra Magnus, who returned to Earth with the STS-119 crew after more than four months in space. ([nasa.gov](
Activities on March 24, 2009
On March 24, the crew focused on preparations for undocking and the return journey to Earth. The day's activities included:
- Supplies and Equipment Transfers: The crew transferred supplies and equipment between Discovery and the ISS, ensuring that all necessary items were accounted for and securely stowed for the return trip. This process was crucial for maintaining the ISS's operational capabilities and supporting the crew's needs during the mission. ([](
- System Checks and Maintenance: Routine system checks were conducted to ensure the shuttle and station were in optimal condition for undocking. This included verifying the integrity of the thermal protection system, communication systems, and life support systems. ([](
- Final Preparations for Undocking: The crew prepared for the scheduled undocking of Discovery at 2:53 p.m. on March 25. This involved securing all hatches, ensuring that all systems were functioning correctly, and reviewing the undocking and deorbit procedures. ([](
Challenges and Resolutions
Throughout the mission, the crew encountered and addressed several challenges:
- Unpressurized Cargo Carrier Attach System (UCCAS) Issue: During the mission, the crew faced difficulties with the UCCAS, which is used to secure cargo carriers to the shuttle. The issue was traced to an incorrectly installed locking pin. The crew worked with Mission Control to troubleshoot and resolve the problem, ensuring the safety and success of the mission. ([nasaspaceflight.com](
- Water Recovery System Component Replacement: A failed component in the ISS's water recovery system was identified. The crew successfully replaced the faulty unit, maintaining the station's ability to recycle water and support the crew's needs. ([nasa.gov](
Significance of the Mission
STS-119 was a critical mission in the ISS assembly program. By delivering and installing the S6 truss segment and the final set of solar arrays, the crew completed the station's structural backbone and power system, enabling the ISS to support a six-member crew and a broader range of scientific experiments. The successful replacement of the water recovery system component ensured the station's sustainability for future missions. ([nasa.gov](
Conclusion
As of March 24, 2009, the STS-119 mission was progressing smoothly, with the crew diligently preparing for undocking and the return journey to Earth. The successful completion of the mission's objectives would significantly enhance the ISS's capabilities, marking a milestone in international collaboration and human space exploration.