Second chances: SpaceX provided with another opportunity to send IDA to ISS
CAPE CANAVERAL, Fla. — In life, there are few second chances. Spaceflight, however, does provide the occasional chance to get back on the saddle after falling off. SpaceX is hoping the planned Monday, July 18, launch of the CRS-9 Dragon spacecraft to the International Space Station (ISS) will mark just such an opportunity.
On June 28, 2015, a SpaceX Falcon 9 exploded some 139 seconds into the CRS-7 mission. The incident occurred when a strut failed in the launch vehicle’s second stage allowing a helium tank to break free. The resulting “overpressure event” caused the complete loss of the rocket, the CRS-7 Dragon, and the payload it carried.
That payload included the International Docking Adapter 1 (IDA-1), which would have been mated to the space station’s Pressurized Mating Adapter 2 (PMA-2). This would have converted the existing APAS-95 docking interface to the new NASA Docking System (NDS).
NDS is touted as allowing the new fleet of crew-rated spacecraft to dock with the orbiting lab. Whereas crewed vehicles dock with the ISS, most of the cargo freighters that travel to the station are berthed—meaning they are grappled by a crew on the station using its robotic arm and then mated to one of the ISS’ ports.
So far, 2016 has been the “year of SpaceX” with the company repeatedly demonstrating the capability to land stages of their highly-successful Falcon 9 rocket on the “Of Course I Still Love You” Autonomous Spaceport Drone Ship positioned out in the Atlantic Ocean.
SpaceX has already returned both the Falcon 9 rocket and cargo variant of Dragon to service (with the historic April 8, 2016, CRS-8 mission, the company successfully landed that particular Falcon 9’s first stage on the OCISLY).
Landing the 15-story tall first stage on a platform out in the rolling Atlantic is no easy feat, despite the fact SpaceX has demonstrated the ability to do so two additional times since last April’s landing. However, for this mission, SpaceX won’t be attempting an landing on a ship positioned out in the ocean.
According to a report written by Stephen Clark of SpaceFlight Now, the company will attempt its second ground landing at Cape Canaveral Air Force Station’s Space Landing Zone 1 in Florida. Landing should take place some 10 minutes after launch.
The Hawthorne, California-based firm has conducted six Falcon 9 launches this year. SpaceX also has plans to carry out the maiden flight of the company’s Falcon Heavy.
Boeing manufactured IDA-1 and 2. In an interview with SpaceFlight Insider, representatives with the company spoke about what they needed to do to get the piece of equipment ready to fly.
For the company tasked with producing the International Docking Adapters, the loss of IDA-1, while not impacting the development and fielding of this IDA, other requirements came about due to the loss of IDA-1.
“The loss of IDA-1 on SpX-7 really had no bearing on what we were doing on IDA-2,” David Clemen, Boeing director for ISS Development and Modification Projects told SpaceFlight Insider. “We were under contract to produce two IDAs on a schedule and to see them launched on the earliest opportunity. So, when we lost IDA-1, we were already in production of IDA-2, what it really affected was, IDA-3 came along as a result of that.”
Clemen said the size of IDA necessitated it fly in the Dragon trunk. He said they looked at all the potential transportation vehicles, including whether it could fly on an HTV (the Japan Aerospace Exploration Agency’s cargo freighter), back in the design phase of the adapter.
“As part of that exercise, we developed an ICD (Interface Control Document) which defines the physical interfaces between two with SpaceX,” Clemen said. “We spent a lot of time discussing the FSE (Flight Support Equipment) required, understanding more about the trunk, the limitations of the trunk. We developed what we call an Interface Configuration Document that established the loads, how IDA would sit in this trunk, what kind of special support equipment was needed to balance the loads. That went on for a period of about two years as we fine tuned the requirements for transportation.”
Clemen said, as one might expect, the two groups worked closely to get the IDAs integrated onto Dragon in preparation for both the CRS-7 and CRS-9 missions.
CRS-9 is currently slated to get underway at 12:45 a.m. EDT (04:45 GMT) Monday, July 18. The mission will utilize a “Full Thrust” Falcon 9 to ferry the cargo, crew supplies, and experiments to the ISS during an “instantaneous” (one second) launch window.
At present, weather conditions along the Space Coast are predicted to provide a 90 percent chance of being favorable for launch—a rarity given the Sunshine State’s turbulent summers.
Once the Dragon spacecraft with its precious cargo pulls alongside the ISS two days later, members of the Expedition 48 crew will control the robotic Canadarm2 to capture and berth the cargo ship to the nadir port of Harmony.
SpaceX’s Falcon 9 family of boosters consist of two stages and burn a mixture of liquid oxygen (LOX) and rocket-grade kerosene (RP-1). The family of rockets first took to the skies in July 2010 on a demonstration flight. Since that time, the NewSpace firm has launched various versions of the rocket 26 times—with the only anomaly marring a near-perfect record being the CRS-7 mission.
The version of the Falcon 9 tapped to fly the CRS-9 mission is capable of lifting some 50,300 pounds (22,800 kilograms) to low-Earth orbit and 18,300 pounds (8,300 kilograms) to a geostationary transfer orbit.
Video courtesy of NASA / Johnson Space Center
Jason Rhian spent several years honing his skills with internships at NASA, the National Space Society and other organizations. He has provided content for outlets such as: Aviation Week & Space Technology, Space.com, The Mars Society and Universe Today.