Tuesday, July 2, 2013

Failure is not an option...


 

Last night’s explosive crash of a Russian Proton rocket attempting to launch three satellites into orbit dramatically pointed out a fundamental difference between the U.S. and Russian space programs: Russian rockets do not contain Flight Termination Systems.

Uncontrolled destruction: last night's chaotic Proton launch.

 
For the United States programs, keeping launches within their specified safe flight launch corridors is a primary concern. Depending on population density, two methods of terminating a launch can be used.
One method, utilized in cases where the potential for harm on the ground is deemed to be low, essentially involves cutting off the fuel to the propulsion system and letting the vehicle fall.
The other involves the utilization of explosives to destroy the vehicle in flight. The goal, of course, is to prevent a massive rocket from wandering off on its own trajectory – as the Proton did last night – but also to ensure that as much as possible of the rocket’s fuel is destroyed or consumed in the atmosphere.

Controlled destruction: a Titan IVA is safely brought down in the wake of catastrophic guidance problems.

 
One of the more spectacular examples of a termination system in action occurred on August 12, 1998, when a huge Titan IVA rocket was detonated off the Florida coast 41 seconds into flight. It was later determined that an electrical short caused by faulty insulation on a wire began to cause problems as normal launch vibrations shook the Titan. The guidance computer went offline, came back on, and attempted pitch and yaw maneuvers that exceeded the structural capacity of the Titan. Within moments, with the rocket at an altitude of 20,000 feet, explosive charges ignited which brought the flight to a safe – but expensive – conclusion.

Logo for the group charged with ensuring a rocket doesn't land in your backyard.
           
Range safety and flight termination standards are a shared concern for all U.S. launch operations. Indeed, the Range Commanders Council has compiled a near-500-page Flight Termination Systems Commonality Standard that addresses these issues. You can explore the topic in detail right here:   Flight Termination Systems Commonality Standard PDF 

At no time does the job description of the Range Safety Officer become more difficult than when the flight is manned. It’s a topic no one liked to think about, but having witnessed shuttle launches from as close as media were allowed, I can attest to the fact that an out of control shuttle stack would have been be an entity of nearly unfathomable force. Which is why both the external tank and solid rocket boosters of the assembly carried termination systems – though the orbiter itself did not. This aspect of the system only came into play once: in the moments after the tragic destruction of Challenger, the Range Safety Office bore the responsibility of destroying the two solid rocket boosters that had continued to fly on after the initial explosion.

Knowing that the Russian rockets do not carry such termination systems would likely have me thinking twice about attending a Proton launch – especially since this is the fifth failure of this launch system in two-and-a-half years. A 19-story rocket that weighs over 1.5 million pounds with a mind of its own? That is a scary thought…

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