Bolting Down 3.6 Million Pounds of Thrust

The solid rocket is armed, the countdown is in its final minutes as NASA and ATK prepare to ignite Ares I five-segment first stage designed to take humans out of Earth’s gravitational pull — this time; however, the rocket isn’t going anywhere.

Engineers at ATK install new mid-span to support Ares I solid rocket motor design. (ATK)

The Ares I development motor, or DM-1, will be tested at Alliant Techsystem’s (ATK) test stand in Promontory, Utah on August 27. With a magnificent flash of light the 154-foot solid rocket motor will come to life, producing heat two-thirds the temperature of the sun and 3.6 million pounds of thrust from its 12-foot diameter cylinder.

Spectators will first see the flame of the motor, so bright the majority will wear sunglasses, then a few seconds later the sound wave will be heard, followed by the ground shaking. Those in attendance will gain a true understanding of the power produced by this motor.

Called by some an “engineering masterpiece,” the first stage is capable of producing 22 million horsepower which is equivalent to the energy produced by 25,882 race cars. So how do ATK and NASA hold down one of the world’s most powerful rockets?

The load measurement system on ATK’s test stand which is attached to the thrust block. (ATK)

“It’s comparable to an ice berg or an upside down mushroom where the majority of this massive test stand is underground,” said Gary Bates, chief test engineer for ATK Space Systems. “This motor is designed to go places, so we need to ensure that it can’t.”

The test stand is made out of 7,000 cubic yards of concrete, 308 tons of reinforced steel and 230 tons of steel plates and rails. It includes a 16-foot tall by 40- foot long, and 20-feet wide above ground concrete fixture, or thrust block, which is attached to an extremely large buried foundation measuring more than 100 feet long by 80 foot wide and almost two-stories below the ground.

The test stand also includes a new, mid-span support which was installed to support the weight of the longer five-segment motor for approximately 70 seconds until enough propellant has been consumed to lighten the weight of the motor.

Newly installed mid-span support for the Ares I five-segment solid rocket motor. (ATK)

The rocket is installed horizontally with attachments at the front and aft ends of the stand. More than a hundred fasteners up to 2.5 inches in diameter help hold the motor in place. At the thrust block, the first stage is attached to a load measurement system.  This system is designed to not only handle up to 4.3 million pounds of force, but measure it.

“Along with securing the motor in the test stand, we need to be able to collect data during its operation,” said Bates. “This data is vital in understanding how the motor performs to compare with flight and other ground test data.” 

Once the test is complete, NASA and ATK will be able to use the information in collaboration with data collected from the Ares I-X test flight this fall, to finalize the design of Ares I first stage.

For more information about the Ares rockets or to watch the DM-1 hot fire test live, visit:

7 thoughts on “Bolting Down 3.6 Million Pounds of Thrust”

  1. Didn’t ATK already test a 5 segment motor in 2003? What happened to the modifications for that one?

  2. ATK did test a 5-segment solid rocket motor in 2003. Because of the weight of the motor, the motor sagged a few inches during the 2003 test. Better tooling to hold motor in and the mid-span support were added for DM-1 and future Ares testing.

  3. What a monster! I hope all goes well.I hope man can step on the moon again and go on to mars not long after that.

  4. Can you people please stop wasting this money on the manned missions that have produced basically NOTHING in the last 20 years? Just focus on the unmanned missions. That is where the real science and exploration is done.

  5. Even the scientists who testified before the Augustine Committee agreed there was value in crewed missions! Not all science can be performed by robots. The best approach is to use crewed missions for highly complex missions and robots for simple ones. For example, humans do a better job of collecting geological samples than robots. The excellent geological samples collected from the moon are being used to this day to advance science.

  6. This is not only Science it is part of our mythology. We must be the Heroes of our own history. Press on and succeed.

Comments are closed.