No Lightweights for Ares I-X Upper Stage Simulator
Vince Bilardo may be the only rocket designer in history without a weight problem.
Instead of trying to make an upper stage simulator for next year’s Ares I-X test flight as light as possible, Billardo and his team from NASA’s Glenn Research Center in Ohio were given no weight restrictions, only guidelines for how it had to look on the outside.
Steel replaced aluminum and other exotic materials as the designers and builders assembled 11 large cylinders. That will change for the operational Ares I rocket when weight control will return as a primary factor for designers.
"This is essentially bridge construction-grade steel," Bilardo said as he walked among the cylinders inside the Vehicle Assembly Building at NASA’s Kennedy Space Center in Florida.
Even with nine cylinders of 1/2-inch-thick steel and two more of 3/4-inch-thick steel, Bilardo’s team had to build a place for 150,000 pounds in steel plates to accurately simulate the weight of a fueled upper stage.
The segments will be stacked on top of each other in coming months as the elements of the first Ares I rocket come together at Kennedy. The cylinders, which match the diameter of the Ares I upper stage, will be stacked on top of a solid rocket booster like the ones the space shuttle uses.
Only the first four segments of the first stage will be active for the Ares I-X test. A fifth segment, the upper stage and an Orion spacecraft at the top will be sensor-laden mass simulators.
Nor will astronauts be inside the spacecraft for the test flight. NASA has not tested a brand-new launch vehicle design for human flight since the space shuttle made its first flight in April 1981.
The Ares I-X mission focuses on the first stage. Engineers have developed complex computer models to predict how the rocket will behave in flight, but managers want actual flight data to back up their projections. The first stage is based on the space shuttle’s solid rocket boosters, which have always flown in pairs.
The test flight will measure in detail what a single booster with a large stage standing on top of it will do as it leaves the launch pad and soars into the upper atmosphere.
"It’s one big data probe that we are flying through the most demanding ascent phase," said Jeff Hanley, manager of the Constellation Program. Constellation includes the Ares I and V rockets, the Orion spacecraft and the Altair moon lander.
The upper stage simulator will not fly for long. After the first stage burns out about two minutes after liftoff, it will separate and the upper stage will soar along unpowered until it splashes down in the South Atlantic Ocean.
While the rocket comes together at Kennedy for the test flight, other aspects of the Constellation Program are progressing as well. Designs are moving through review stages steadily, including the new engine being developed to power the Ares I upper stage.
Steven Siceloff, Kennedy Space Center