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Ares I-X

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Ares I-X
 
When the Ares I-X was being rolled out, it could only travel at speeds of 0.8 miles per hour.
Platforms surround the Ares I-X in High Bay 3 of the Vehicle Assembly Building before it was moved to the launch pad.

Ares I-X is the first test flight in the Ares I development program. Ares I is a launch system for human spaceflights being developed by NASA, the space agency of the United States. The vehicle used for the Ares I-X suborbital test flight will be similar in shape, weight and size to the planned configuration of later Ares I vehicles, but will have largely dissimilar internal hardware. Ares I-X is scheduled for launch on October 27, 2009.

Ares I vehicles are intended to launch Orion crew exploration vehicles. Along with the Ares V launch system and the Altair lunar lander, Ares I and Orion are part of NASA's Constellation Program, which is developing spacecraft for U.S. human spaceflight after the Space Shuttle fleet is retired.

Configuration

Section data: AIAA'[1]

The weight of the rocket is 816,466 kg.[2]

Test objectives

Ares I-X will be the first test flight of a launch vehicle like the Ares I. The test flight objectives include:

  • Demonstrating control of a dynamically similar vehicle using control algorithms similar to those used for Ares I.
  • Performing an in-flight separation/staging event between an Ares I-similar First Stage and a representative Upper Stage.
  • Demonstrating assembly and recovery of an Ares I-like First Stage at Kennedy Space Center (KSC).
  • Demonstrating First Stage separation sequencing, and measuring First Stage atmospheric entry dynamics, and parachute performance.
  • Characterizing the magnitude of integrated vehicle roll torque throughout First Stage flight.

The flight also has several secondary objectives, including:

  • Quantifying the effectiveness of the first stage booster deceleration motors.
  • Characterizing induced environments and loads on the vehicle during ascent.
  • Demonstrating a procedure for determining the vehicle’s position to orient the flight control system.
  • Characterize induced loads on the Flight Test Vehicle while on the launch pad.
  • Assess potential Ares I access locations in the VAB and on the Pad.
  • Assess First Stage electrical umbilical performance.

The Ares I-X flight profile (Figure X) will closely approximate the flight conditions that Ares I will experience through Mach 4.5, at an altitude of about 130,000 feet (39,600 m) and through a maximum dynamic pressure (“Max Q”) of approximately 800 pounds per square foot (38.3 kPa).

The rocket is split into separate parts that separate at different times in the launch.

Figure X: The Ares I-X flight profile resembles the uncrewed Saturn I flights of the 1960s, which tested the Saturn propulsion concept.

By flying the vehicle through first stage separation, the test flight will also verify the performance and dynamics of the Ares I solid rocket booster in a “single stick” arrangement, which is different than the solid rocket booster’s current “double-booster” configuration alongside the external tank on the space shuttle.[3]

Description

The Ares I–X vehicle will consist of a functional four-segment solid rocket booster stage, a fifth segment mass simulator, an upper stage simulator (USS), which will be similar in shape and heavier than the actual upper stage, as well as a simulated Orion crew module (CM) and launch abort system (LAS). Since the actual upper stage hardware cannot be produced in time for the flight test, the upper stage mass simulator will allow the booster to fly approximately the same trajectory through the first stage of flight. The USS and the CM/LAS mass simulators launched by the Ares I-X will not be recovered because they will fall into the Atlantic ocean. The first stage, including the fifth segment mass simulator, will be recovered to retrieve flight data recorders and reusable equipment.

First Stage

The first stage.

The four-segment solid rocket motor and aft skirt for Ares I-X was drawn directly from the Space Shuttle inventory. The motor was manufactured by ATK Launch Services of Promontory, Utah.[4] The new forward structures were manufactured by Major Tool & Machine of Indianapolis, Indiana. The first stage element is being managed by Marshall Space Flight Center in Huntsville, Alabama. Modifications to the solid rocket booster include:

  • The aft skirt has been modified to include eight booster deceleration motors, which will pull the booster directly away from the upper stage simulator, as well as four booster tumble motors, which will cause the booster to tumble horizontally to decrease its velocity prior to reentry. The aft skirt will also house one of two Redundant Rate Gyro Units (RRGUs), which will provide data to inform the Fault Tolerant Inertial Navigation Unit (FTINU) of the vehicle’s attitude and position. Steel ballast of 3,500 pounds has been added to the aft skirt as well to move the first stage’s center of gravity aft to ensure that the first stage will tumble properly after separation.
  • An extended service tunnel along the exterior, which will accommodate:
  • An extended linear shaped charge for the flight termination system, to cover all four segments in the event the stage needs to be self-destructed.
  • Cabling for additional pressure and environmental instrumentation.
  • A fifth segment simulator, which will allow the Ares I-X to simulate the length and mass of the Ares I five-segment motor and will house the First Stage Avionics Module (FSAM). The FSAM contains the electronics boxes that will:
  • Capture and store flight data for recovery after splashdown.
  • Perform separation and parachute deployment commands.
  • A hollow forward skirt which simulates the Ares I First Stage forward skirt.
  • A forward skirt extension, which will house new, larger parachutes. The three main parachutes each have a 150-foot (46 m) diameter, compared to the Shuttle booster main parachutes, which are 136 feet (41 m) across. It also has a Shuttle booster heritage nosecap that covers the pilot and drogue parachutes. Jettisoning the nosecap will release the pilot parachute which pulls out the drogue. The forward skirt extension separates from the booster deploying the main parachutes.
  • A frustum, which is a hollow, inverted half-cone that connects the 12-foot-diameter first stage to the 18-foot-diameter upper stage simulator.
File:Ares I-X First Stage.jpg
A diagram of the inside of the first stage.

For the Ares I-X flight test, the frustum and forward skirt extension will be made of aluminum. The forward skirt and fifth segment simulator will be made of steel.[3]

Upper Stage Simulator

The upper stage simulator (USS) was manufactured by NASA personnel at Glenn Research Center in Cleveland, OH. Because of transportation limitations (bridge heights on highways and rivers), the simulator was built out of eleven steel segments 9.5 feet (2.9 m) tall by 18 feet (5.5 m) wide. The USS will simulate the shape, mass, and center of gravity characteristics of Ares I from the interstage to the top of the service module of the Orion Crew exploration vehicle. The centers of mass for the liquid hydrogen and liquid oxygen tanks are being simulated through the use of steel ballast plates.

The upper stage simulator.

The USS will include a variety of temperature, vibration, thermal, and acoustic sensors to collect the primary data needed to meet the mission objectives. It will also house the Fault Tolerant Inertial Navigation Unit (FTINU), which will control the vehicle’s flight and primary avionics functions. For stability, the FTINU will be mounted on the underside of the lower ballast plates. Ground operations personnel will access the FTINU through a crew hatch on the side of the interstage segment, which also houses the roll control system. Each USS segment will include a ladder and ring-shaped platform to allow access to the sensors and cabling for the developmental flight instrumentation. The stairs and platforms are necessary because Launch Complex 39B is not tall enough to provide crew access to the upper parts of Ares I-X.[5]

Roll Control System

The active roll control system (RoCS) is needed because the flight test vehicle will have a tendency to roll around its axis of forward motion. The RoCS for Ares I-X consists of two modules containing engines originally used on now-decommissioned Peacekeeper missiles. The RoCS will perform two primary functions:

  • Rolling the vehicle 90 degrees after liftoff to emulate the Ares I roll attitude at launch.
  • Maintaining a constant roll attitude during ascent up to stage separation.

The RoCS modules, placed on opposite sides of the outer skin of the Upper Stage Simulator, use hypergolic monomethyl hydrazine (MMH) and nitrogen tetroxide (NTO) for propellants and each include two nozzles, which fire tangential to the skin and at right angles to the roll axis in order to provide a controlling roll torque. The propellants will be loaded into the modules at Kennedy Space Center’s Hypergol Maintenance Facility (HMF) and transported on the ground for installation into the USS in the Vehicle Assembly Building (VAB) prior to rollout to Launch Complex 39B.

The roll control system.

The RoCS modules were designed and constructed to fit into the Interstage segment of the USS by Teledyne Brown Engineering in Huntsville, Alabama.[6] The engines were hot-fire tested at White Sands Test Facility in 2007 and 2008 to verify that they could perform the pulsing duty cycle required by Ares I-X.

Crew Module/Launch Abort System Simulator

At the top of the Ares I-X flight test vehicle will be a combined Orion crew module and launch abort system simulator, resembling the structural and aerodynamic characteristics of Ares I. The full-scale crew module (CM) is approximately 16 feet (5 m) in diameter and 7 feet (2.1 m) tall, while the launch abort system (LAS) is 46 feet (14 m) long.

The CM/LAS simulator was built with high fidelity to ensure that its hardware components accurately reflect the shape and physical properties of the models used in computer analyses and wind tunnel tests. This precision will enable NASA to compare CM/LAS flight performance with preflight predictions with high confidence. The CM/LAS simulator also will help verify analysis tools and techniques needed to further develop Ares I.

Ares I-X flight data will be collected with sensors throughout the vehicle, including approximately 150 sensors in the CM/LAS simulator that will record thermal, aerodynamic, acoustic, vibration and other data. Data will be transmitted to the ground via telemetry and also stored in the First Stage Avionics Module (FSAM), located in the empty fifth segment.

Aerodynamic data collected from sensors in the CM/LAS will contribute to measurements of vehicle acceleration and angle of attack. How the tip of the rocket slices through the atmosphere is important because that determines the flow of air over the entire vehicle.

The CM/LAS will splash down in the ocean along with the upper stage simulator (USS) after the boost phase of the mission.

This simulator was designed and built by a government-industry team at Langley Research Center in Virginia. It was flown to Kennedy Space Center by C-5 transport and will be the last piece of hardware stacked onto the rocket in the Vehicle Assembly Building.[7]

Avionics

Ares I-X will use avionics hardware from the Atlas V Evolved Expendable Launch Vehicle (EELV) to control its flight. This includes the Fault Tolerant Inertial Navigation Unit (FTINU) and Redundant Rate Gyro Units (RRGUs), and cable harnesses. The first stage will be controlled primarily by heritage hardware from its existing Space Shuttle systems. A new electronics box, the Ascent Thrust Vector Controller (ATVC), will act as a translation tool to communicate commands from the Atlas-based flight computer to the solid rocket booster’s thrust vector control system. This is the only new avionics box for the flight. All other components are existing or off-the-shelf units. Ares I-X also will employ 720 thermal, acceleration, acoustic, and vibration sensors as part of its developmental flight instrumentation (DFI) to collect the data necessary for the mission. Some of this data will be transmitted real-time via telemetry while the rest will be stored in electronics boxes located in the First Stage Avionics Module (FSAM), located inside the hollow first stage fifth segment.

The avionics.

The ground-based portion of the mission’s avionics includes a ground control, command, and communications (GC3) unit, which will be installed on the Mobile Launch Platform (MLP) for launch at Launch Complex 39B at Kennedy Space Center. The GC3 unit enables the flight control system to interface with computers on the ground. The flight test vehicle will fly autonomously and be controlled by the FTINU, located on the underside of the lower ballast plates of the upper stage simulator (USS).

The avionics are being developed by Lockheed-Martin of Denver, Colorado, a subcontractor to Jacobs Engineering of Huntsville, Alabama, and is managed by Marshall Space Flight Center in Huntsville, Alabama.

Processing

Ground Operations

Ground operations includes activities such as vehicle stacking, integration, rollout, and liftoff, while ground systems include vehicle interfaces and lightning protection. Several new procedures and hardware items have been developed for Ares I-X, including:

  • A new, taller lightning protection system for Launch Complex 39B, which will be taller than the existing tower used for Space Shuttle operations.
  • A Shuttle-era firing room has been updated with new computer hardware to support Constellation.
  • A platform inside the Vehicle Assembly Building has been removed to allow the Ares I-X vehicle to fit and roll out.
  • A new vehicle stabilization system (VSS), which will keep the vehicle from swaying on the launch pad after rollout. The VSS will use off-the-shelf hydraulic shock absorbers from the Monroe division of Tenneco, Inc.
  • The ECS interfaces to the rocket will be “T-0” units, meaning they will disconnect from the launch vehicle automatically when the countdown reaches zero.

Ground operations and ground systems are being handled by United Space Alliance and NASA personnel at Kennedy Space Center.

Systems engineering and integration

The Ares I-X Systems Engineering & Integration (SE&I) Office, managed by the NASA Langley Research Center, is responsible for integrating the vehicle’s parts into a complete rocket and making sure they work together as a system to meet flight test objectives. SE&I is responsible for ensuring all components will function collectively to satisfy primary and secondary mission objectives. Detailed management of system interfaces, mission level requirements, validation plans, and flight instrumentation management are key SE&I contributions. SE&I provides the structural, thermal and aerodynamic analyses for the overall system to allow the components to be designed and built. SE&I also manages the mass of the vehicle and develops the trajectory and the guidance, navigation, and control algorithms used for vehicle flight.

To complete these tasks, wind tunnel testing and computational fluid dynamics (CFD) are used to investigate forces acting on the vehicle in various phases of flight, including lift-off, ascent, stage separation and descent. Once the basic design is understood SE&I provides structural analyses for the system to assure the rocket will behave properly once it is integrated.

See also

Wikimedia Commons has media related to Ares I-X.

References

  1. ^ AIAA: Ares I-X Configuration, Oct. 2007
  2. ^ Tariq Malik (October 21, 2009). "NASA Unveils Ares 1-X Rocket for Historic Test Flight". Fox News.
  3. ^ a b http://www.nasa.gov/mission_pages/constellation/ares/flighttests/aresIx/index.html
  4. ^ http://www.floridatoday.com/content/blogs/space/2009/02/ares-i-x-segments-prepped-for-trip-to.shtml
  5. ^ http://blog.cleveland.com/metro/2008/03/ares_ix_upper_stage_simulator.html
  6. ^ http://www.spaceref.com/news/viewpr.rss.html?pid=27446
  7. ^ http://www.reuters.com/article/pressRelease/idUS229938+22-Jan-2009+PRN20090122
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