for National Geographic News
With NASA's Ares I-X rocket set to launch tomorrow morning, mission managers are hopeful that the $450-million test flight will be a first concrete step toward returning humans to the moon and beyond.
The Ares I-X—now the largest rocket in the world at 327 feet (99.6 meters) tall—is a test version of a system designed to carry a four- to six-person crew capsule, dubbed Orion. (See pictures of Ares, Orion, and other craft in NASA's plans to return humans to the moon.)
Together, Ares and Orion are slated to become NASA's primary means of ferrying people and supplies into space, replacing the space shuttle program, which is due to retire in 2010.
Ares I-X is the first test version of the new rocket, a full-scale simulation that will launch carrying a mock Orion capsule and launch-abort system.
According to NASA, more than 700 sensors will collect data during the rocket's roughly six-minute flight.
This information "will be used to verify the effectiveness of the rocket's design and ensure that it is safe and stable in flight before astronauts begin traveling into orbit."
Ares I-X Flight Plan
In a real Ares I rocket the first part, or stage, would propel the craft into space at up to four times the speed of sound.
The first stage would then separate, and the second stage would provide enough thrust to position the Orion capsule into Earth orbit.
NASA eventually plans to build an Ares V rocket, which would work in tandem with Ares I. Ares V would deliver the Altair lunar lander into orbit, where it would rendezvous with Orion, fire engines to break free from Earth's gravity, and speed toward the moon.
The Ares I-X test rocket will be similar in size and mass to the real deal. But only the first stage will include working hardware: a solid-rocket motor from the space shuttle, flight hardware adapted from an Atlas V rocket, and a set of newly designed parachutes.
The upper stage and crew capsule will be mockups designed to simulate the shape and weight of the real pieces the Ares I rocket will eventually need to carry into space.
At two minutes into the Ares I-X flight, the first stage will separate at about 130,000 feet (39,624 meters) and fall back down to reenter Earth's atmosphere, parachuting into the Atlantic Ocean for recovery.
The simulated upper stage and crew capsule will continue uncontrolled up to 28 miles (45 kilometers) above Earth's surface before falling back through the atmosphere and crashing into the Atlantic.
The upper section of Ares I-X will not be recovered.
Ares Rocket a Lost Cause?
The Ares I-X launch marks the test of NASA's first new human-powered vehicle since the space shuttle was unveiled in the 1980s.
NASA hopes Ares I-X will signal the beginning of a brave new era for space exploration. But some experts argue that the rocket is simply the expenditure of some very costly hot air.
Given the high price tag, some vocal critics—including legendary "moon walker" Buzz Aldrin—want to pull the plug on Ares and rely on battle-tested Delta IV or Atlas V rockets, modified for new missions.
Others have proposed designing new crew vehicles that will work with existing lift components from the space shuttle. This plan would deliver a less powerful but far cheaper way to return to the moon, though not beyond.
And earlier this month, a panel of experts dubbed the U.S. Human Space Flight Plans Committee reported that upcoming funding shortages could force NASA to curb many of its ambitious plans, including Ares.
But committee members are quick to point out that the rocket was not given an absolute death knell.
"Comments in the blogosphere that we [recommended] killing Ares are just not true," said committee member and former NASA astronaut Leroy Chiao.
"We presented options [for the future of human spaceflight]—that was our mandate—and Ares I appears in two of the options."
Final decisions on NASA's future course of action will be made in Congress and the White House.
"It's far from certain what path the [Obama] Administration is going to choose," Chiao said. "There are options that include Ares and options that do not include Ares, so the jury is still out."
Weather May Stall Ares Test
Meanwhile, the final call on the Ares I-X launch now lies with Mother Nature.
Weather forecasts call for clouds tomorrow morning, which could disrupt rocket-to-ground communications and prevent the streaming flow of performance data that would make the test drive so valuable.
Officials warned this week that if launches are scrubbed Tuesday and Wednesday, a swamped schedule at Kennedy Space Center could delay the Ares I-X test flight until December or even early 2010.
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