How does NASA destroy its rockets?

Answers to your questions about the news.
Aug. 25 2008 6:29 PM

How Do You Blow Up a Rocket?

Just flip on its flight termination system.

Illustration by Mark Alan Stamaty. Click image to expand.

Early Friday morning, the National Aeronautics and Space Administration terminated an experimental rocket soon after it launched from the Wallops Flight Facility in Virginia. The rocket had veered off course and was in danger of landing in a populated area. How does NASA torpedo a rocket?

By turning it off. Contrary to some press reports, NASA didn't "blow up" the rocket since a big explosion was precisely the scenario the agency was hoping to avoid. All guided vehicles are required to carry a network of electrically rigged explosives that can be detonated by radio commands from the ground, known as a "flight termination system." This system allows the rocket to be disabled with a series of small explosions midflight, so it can fall safely to earth should NASA officials discover any dangerous malfunctions after launch.

Advertisement

In this case, the order to abort the flight triggered the FTS to shut down the rocket by deactivating both of its stages. (A rocket stage is a motor that contains its own igniter and propellant; each stage fires in turn, then falls off once it runs out of fuel.) Explosives on both stages detonated simultaneously, splitting open their casings and allowing the hot gases that power them to dissipate into the air. Without fuel for the stages, a neutralized rocket continues moving for as long as its momentum can carry it—and then (in theory) comes down within pre-established safe boundaries.

The decision to terminate a rocket flight is made by NASA's range safety officers. Whenever a rocket is launched, engineers take into consideration that it might veer off course a bit, due to onboard system problems or external weather conditions. So prior to launch, these safety specialists determine how far, and in what direction, the rocket can travel without endangering people or property should it malfunction and fall. (Factors in these calculations include the size and type of the rocket, the planned flight path, whether the rocket has been tested before, and how densely the area around the launch facility is populated.) The range for Friday's rocket allowed for approximately 16 degrees of deviation from the planned flight path. The safety officers monitored the rocket using both radar and onboard telemetry systems; soon after launch, it began veering south, putting it on course to pass out of the acceptable safety range. At that point the observers turned on the flight termination system.

The Wallops facility, which is the only launch base where NASA directly oversees range safety (all other launch sites are overseen by the Air Force), has handled an average of 20 to 25 rocket launches annually during the past two decades. The last time a rocket was terminated early at Wallops was in 1995, when the Conestoga 1620 disintegrated in midair 46 seconds after launch. In the case of the Conestoga—which, like Friday's rocket, was on its maiden voyage—the vehicle began breaking up on its own, and the FTS was initiated as a backup precaution. (Manned space shuttles, which are launched from Kennedy Space Center, have similar termination systems; astronauts are given parachutes, survival suits, rafts, and other survival gear.)

Got a question about today's news? Ask the Explainer.

Explainer thanks Bryce Hallowell, Trina Patterson, and Kent Rominger of Alliance Techsystems and Keith Koehler and David Steitz of NASA.

Nina Shen Rastogi is a writer and editor, and is also the vice president for content at Figment.

TODAY IN SLATE

Politics

Smash and Grab

Will competitive Senate contests in Kansas and South Dakota lead to more late-breaking races in future elections?

Even When They Go to College, the Poor Sometimes Stay Poor

Republicans Want the Government to Listen to the American Public on Ebola. That’s a Horrible Idea.

The Most Ingenious Teaching Device Ever Invented

Tom Hanks Has a Short Story in The New Yorker. It’s Not Good.

Brow Beat

Marvel’s Civil War Is a Far-Right Paranoid Fantasy

It’s also a mess. Can the movies do better?

Space: The Next Generation

An All-Female Mission to Mars

As a NASA guinea pig, I verified that women would be cheaper to launch than men.

Watching Netflix in Bed. Hanging Bananas. Is There Anything These Hooks Can’t Solve?

The Procedural Rule That Could Prevent Gay Marriage From Reaching SCOTUS Again

  News & Politics
Politics
Oct. 20 2014 7:13 PM Deadly Advice When it comes to Ebola, ignore American public opinion: It’s ignorant and misinformed about the disease.
  Business
Moneybox
Oct. 20 2014 7:23 PM Chipotle’s Magical Burrito Empire Keeps Growing, Might Be Slowing
  Life
Outward
Oct. 20 2014 3:16 PM The Catholic Church Is Changing, and Celibate Gays Are Leading the Way
  Double X
The XX Factor
Oct. 20 2014 6:17 PM I Am 25. I Don't Work at Facebook. My Doctors Want Me to Freeze My Eggs.
  Slate Plus
Tv Club
Oct. 20 2014 7:15 AM The Slate Doctor Who Podcast: Episode 9 A spoiler-filled discussion of "Flatline."
  Arts
Brow Beat
Oct. 20 2014 6:32 PM Taylor Swift’s Pro-Gay “Welcome to New York” Takes Her Further Than Ever From Nashville 
  Technology
Future Tense
Oct. 20 2014 4:59 PM Canadian Town Cancels Outdoor Halloween Because Polar Bears
  Health & Science
Medical Examiner
Oct. 20 2014 11:46 AM Is Anybody Watching My Do-Gooding? The difference between being a hero and being an altruist.
  Sports
Sports Nut
Oct. 20 2014 5:09 PM Keepaway, on Three. Ready—Break! On his record-breaking touchdown pass, Peyton Manning couldn’t even leave the celebration to chance.