Ares 1-X rocket arrives at launch pad for test flight
BY STEPHEN CLARK
Posted: October 20, 2009
The Ares 1-X demo booster was carted to its launch pad early Tuesday, arriving at a complex that underwent a multi-million dollar facelift to support the one-off test flight for NASA's next-generation moon program.
The mammoth crawler-transporter lowered the launch deck atop pedestals at the pad, officially completing the rollout.
The skyscraping rocket is the tallest booster to dot the Cape Canaveral skyline since the Saturn 5 moon rocket last flew in 1973.
"This is just a test rocket and it's larger than any other rocket on the planet," said Jon Cowart, the deputy mission manager.
Scheduled to launch next Tuesday, the $445 million mission will hand engineers data on the environments the Ares 1 rocket will encounter during the first two minutes of flight.
The rocket is made up of a scaled-down four-segment solid rocket booster first stage and aerodynamic simulators for the Ares 1's upper stage, the Orion crew module and the launch abort system.
Cowart said the next few days will be spent servicing the first stage's hydraulic steering system to prepare for a hotfire of the unit later this week.
A countdown simulation is on tap for Thursday and all of the rocket's computers and parts will be exercised in an integrated systems test.
"We've got to do a lot of prep work for that. We'll power up the rocket, let it do a countdown, let it think that it's reached T-zero and going to go fly and make sure the rocket responds correctly," Cowart said.
An agency-level Flight Test Readiness Review is on tap for Friday to discuss preparations and a mound of open paperwork before launch.
Ares 1-X has three consecutive days to launch beginning Oct. 27 before the Air Force's Eastern Range is unavailable. That could force a delay until early November if the rocket does not get off the ground.
Launch pad 39B, now retired from service in the space shuttle program, was modified to support the test flight.
The agency spent more than $13 million for one-time modifications to the pad, plus another $28 million for construction of three new lightning towers that will be used for future Ares launches.
Engineers say the most significant change to the pad was the installation of a vehicle stablization system at the complex's 195-foot-level.
"This is a large structure that has dampers and springs. Once the Ares 1-X vehicle gets out to the launch pad, we will grapple onto it. And that will help if for whatever reason the winds pick up over the next week to stabilize that vehicle and keep it from moving too much so we can continue work inside," said Mike Stelzer, the Ares 1-X ground systems project manager.
Technicians will quickly attach the stabilizer arm to the rocket because it helps protect the slender vehicle against strong winds.
"The first thing we do when we get out here is we go ahead and provide access to the vehicle for the crew to get up there on the stabilizer. We'll rotate the stabilizer arms together and then begin to grapple the vehicle. That's really one of the first things we do after the mobile launch platform is hard-down at the pad," Stelzer said.
The new wind damper system was put at the location that used to hold the orbiter access arm, the pathway astronauts followed when boarding space shuttles.
After the vehicle stabilization system is extended, engineers will next move other access platforms into place before wheeling the rotating service structure around the rocket Tuesday afternoon.
The gaseous oxygen vent hood, a white object commonly called the "beanie cap," was also removed and replaced with an upper stage access platform and environmental control system ducting.
The new plumbing will control the atmosphere inside the upper stage simulator during the pad stay.
A third change to the launch pad was the addition of a small balcony-like arm on the rotating service structure. When the structure is extended, the platform will give engineers access to the rocket's primary avionics bay near the top of the first stage.
Three hard-to-miss lightning towers were also erected last winter. The 602-foot-tall masts will be the only structures left at pad 39B when the complex is demolished in the next couple of years during another round of modifications for future Ares launches.
Plans call for the lightning protection system to be used by operational flights of the Ares 1.
But for now, workers have only strung a single catenary wire between two of the masts. That will provide enough shielding from lightning strikes for Ares 1-X's one-week stay at the complex.
"There's still more work to do on the lightning protection system, but we got it to give us a good amount of protection for Ares 1-X," Stelzer said.
Another big change at the launch pad was the removal of the shuttle-era lightning tower atop the complex's primary structure.
Engineers also rigged the pad with several dozen pressure, acoustic and vibration sensors to characterize how the complex holds up against the launch.
Officials predict Ares 1-X will put more stress on the pad than a typical shuttle launch.
"Because the drift of Ares 1-X potentially could be much different from shuttle, we actually had to do a lot of beef-up to some of the FSS structure because if it drifts a certain way we could get some plume impingement and see higher loads," said Bill Stover, the missions's deputy ground systems project manager.
Flight designers have programmed the rocket to execute a slight avoidance maneuver moments after liftoff to keep from damaging the pad with its fiery hot motor plume.
The rocket's nozzle will be gimbaled about 1 degree for the "walk off" maneuver.
"We've designed a flyaway maneuver for the nozzle to cant over ever so slightly -- 1 degree -- not that much to us, but with 2 million pounds of thrust, that's going to take the vehicle and help it to fly away from the pad," Stelzer said.
Stover said engineers predict there will be about 15 feet of clearance between the pad and the rocket at liftoff, so there is no threat of physical contact. Officials are only concerned about the affects of the booster's plume.