The Space Shuttles have been the workhorses of NASA for nearly 30
years, but they are due
to be retired soon. NASA is going back to its rocketry
roots with the Constellation program and is developing the new
Ares I and Ares V launch systems as replacements. The Ares I
rocket is intended primarily to launch human astronauts,
while the Ares V will launch automated cargo missions.
The Saturn family of rockets were the first dedicated space
rockets of the United States. All previous rockets used were adapted
from military designs. Rockets such as the Atlas and Titan were
primarily designed as InterContinental Ballistic Missiles (ICBMs),
with the payload being nuclear missiles. This generally worked well
enough for low-earth orbit, but larger and heavier payloads needed a
completely new design dedicated for space. The mighty Saturn V
rockets were what took America to the Moon, and were seen as a symbol
of the technological superiority of the United States.
It is fitting then that the first test flight of the Ares
I rocket was supposed to occur on the 48th anniversary
of the first Saturn I launch. Unfortunately, high winds and poor
weather conditions have led to a postponement.
This test
mission is designated Ares I-X, and is only the first of
several planned test flights that will demonstrate and test multiple
key components of the Ares I system. NASA wants to follow the
methodology of the Apollo program and use multiple tests to validate
their designs. That way improvements can be made early on and
integrated more quickly.
There are two main stages to the Ares I rocket. The First Stage is
a reusable solid
fuel rocket derived from the Space Shuttle's Solid Rocket
Boosters. It features a nozzle with thrust vectoring control. A fifth
segment has been added in order to attain more thrust and a longer
burn, but it will be inert for this test flight. It will be
active during the second Ares I test flight in 2014, currently
designated Ares I-Y.
The Upper Stage will be propelled by a new engine derived from the
Saturn program. The J-2X
engine will be fueled by liquid hydrogen and liquid oxygen.
It will be built by Rocketdyne, the prime contractor for the original
J-2 engines used by Saturn rockets in the Apollo program. The Upper
Stage for Ares I-X will use simulators, but Ares I-Y will use the
real thing.
The Orion crew capsule that will sit atop the Ares
I is still being designed and will not be ready for spaceflight until
2012. Ares I-X uses a non-functional payload of the same size and
shape known as a boilerplate. The entire Upper Stage, including the
boilerplate, will fall into the Atlantic Ocean if all goes
as planned.
The primary test objectives for Ares I-X will be to
demonstrate flight control system performance during ascent and to
test the Parachute Recovery System of the First Stage. The parachutes
use Kevlar and are much stronger and lighter than the nylon versions
currently used during Space Shuttle launches.
Another major goal is to gather data on the Ares I's roll torque
during flight, which will reach a maximum height of 150,000
feet (45.72 KM). Roll torque is a major issue caused by vehicle
aerodynamics and the manner in which the liquid propellant burns.
Computer models have been used so far, but flight safety increases
dramatically as more accurate and precise data is used.
NASA
engineers will bring to bear more than 700 sensors to
collect data during the six minute flight. A through analysis
is not expected to finish until next year. There is a Critical
Design Review currently scheduled for the Ares I in 2011, and the
findings there will be based on lessons from tomorrow's launch.
The
Orion 1 test flight in 2014 will be the first time all of the
components of Ares I will fly together. The first manned test of
Orion is also targeted for 2014 with the Orion 2 mission. Orion 3
through Orion 9 will see the first visits to the International Space
Station starting in 2015.
