Max Launch Abort System
Encyclopedia
The Max Launch Abort System (MLAS) is a proposed alternative to the Max Faget-invented "tractor" Launch Escape System
(LES) currently planned for use by NASA for its Orion spacecraft
in the event an Ares I
malfunction during launch requires an immediate abort.
A "pad abort" flight test of the MLAS was performed at NASA
's Wallops Flight Facility
on July 8, 2009 just after 6:25 a.m. A primary test goal was the successful separation of a mock crew capsule from the abort system.
Designed by NASA engineers and reported on the website nasaspaceflight.com on December 6, 2007, the proposed MLAS uses 4 existing Thiokol-Huntsville built solid-rocket motors (built in 1988) placed at 90° intervals within the Orion's bullet-shaped boost protective cover. The boost protective cover was originally designed to protect the Orion spacecraft from aerodynamic stresses during launch, and to provide an interface between the spacecraft's crew module with the LES.
The MLAS is designed with the aim of reducing the height of the Orion/Ares I stack while also reducing weight and center-of-gravity issues of a traditional LES. The bullet-shaped MLAS is also expected to provide better aerodynamic qualities during the first two minutes of flight, reducing stresses when the vehicle encounters the "Max Q
" regions of hypersonic flight. The MLAS is also expected to simplify production, as existing hardware would be employed.
There are several drawbacks to MLAS. First, the bullet-shaped protective cover would have to be modified and reinforced to allow for the use of the solid-rocket motors, something not needed with the LES, which bolts atop of the LIDS
docking ring assembly. Second, the necessity to fire multiple motors (LES uses one motor and multiple nozzles) simultaneously for an abort decreases the theoretical reliability of the launch abort system by introducing more failure modes.
Like the existing LES, the MLAS would provide protection to the Orion spacecraft crew during the first 2½ minutes of flight, with the MLAS being jettisoned, along with the service module's fairing panels, after the solid-rocket first stage is jettisoned. If implemented, the Orion/Ares I stack would resemble the towerless Gemini-Titan
stack used between 1965–66, in which ejection seats were used as the primary form of escape for the astronauts who flew on the ten Gemini
missions.
The MLAS concept was dropped with the transformation of the CEV into the MPCV, and the switch of the launch vehicle from Ares I (with its perennial underperformance) to Delta IV-Heavy or SLS.
The test vehicle was different from the actual system in many ways. The main difference is that the four propulsion rockets were not located in the forward fairing, but in a boost skirt located at the bottom of the test vehicle. The rockets in the fairing were represented by geometric dummies. The propulsion thrust was not balanced between the rockets by a manifold system, contrary to what is foreseen with the actual system.
Launch escape system
A Launch Escape System is a top-mounted rocket connected to the crew module of a crewed spacecraft and used to quickly separate the crew module from the rest of the rocket in case of emergency. Since the escape rockets are above the crew module, an LES typically uses separate nozzles which are...
(LES) currently planned for use by NASA for its Orion spacecraft
Orion (spacecraft)
Orion is a spacecraft designed by Lockheed Martin for NASA, the space agency of the United States. Orion development began in 2005 as part of the Constellation program, where Orion would fulfill the function of a Crew Exploration Vehicle....
in the event an Ares I
Ares I
Ares I was the crew launch vehicle that was being developed by NASA as part of the Constellation Program. The name "Ares" refers to the Greek deity Ares, who is identified with the Roman god Mars...
malfunction during launch requires an immediate abort.
A "pad abort" flight test of the MLAS was performed at NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
's Wallops Flight Facility
Wallops Flight Facility
Wallops Flight Facility , located on the Eastern Shore of Virginia, is operated by NASA’s Goddard Space Flight Center, primarily as a rocket launch site to support science and exploration missions for NASA and other U.S. government agencies...
on July 8, 2009 just after 6:25 a.m. A primary test goal was the successful separation of a mock crew capsule from the abort system.
Designed by NASA engineers and reported on the website nasaspaceflight.com on December 6, 2007, the proposed MLAS uses 4 existing Thiokol-Huntsville built solid-rocket motors (built in 1988) placed at 90° intervals within the Orion's bullet-shaped boost protective cover. The boost protective cover was originally designed to protect the Orion spacecraft from aerodynamic stresses during launch, and to provide an interface between the spacecraft's crew module with the LES.
The MLAS is designed with the aim of reducing the height of the Orion/Ares I stack while also reducing weight and center-of-gravity issues of a traditional LES. The bullet-shaped MLAS is also expected to provide better aerodynamic qualities during the first two minutes of flight, reducing stresses when the vehicle encounters the "Max Q
Max Q
In aerospace engineering, the maximum dynamic pressure, often referred to as maximum Q or max Q, is the point at which aerodynamic stress on a vehicle in atmospheric flight is maximized...
" regions of hypersonic flight. The MLAS is also expected to simplify production, as existing hardware would be employed.
There are several drawbacks to MLAS. First, the bullet-shaped protective cover would have to be modified and reinforced to allow for the use of the solid-rocket motors, something not needed with the LES, which bolts atop of the LIDS
Low Impact Docking System
The NASA Docking System or international Low Impact Docking System is a spacecraft docking and berthing mechanism being developed by NASA for the next generation of space exploration vehicles, such as the Multi-Purpose Crew Vehicle and the Commercial Crew vehicles...
docking ring assembly. Second, the necessity to fire multiple motors (LES uses one motor and multiple nozzles) simultaneously for an abort decreases the theoretical reliability of the launch abort system by introducing more failure modes.
Like the existing LES, the MLAS would provide protection to the Orion spacecraft crew during the first 2½ minutes of flight, with the MLAS being jettisoned, along with the service module's fairing panels, after the solid-rocket first stage is jettisoned. If implemented, the Orion/Ares I stack would resemble the towerless Gemini-Titan
Titan II GLV
The Titan II GLV or Gemini-Titan was an American expendable launch system derived from the Titan II missile, which was used to launch twelve Gemini missions for NASA between 1964 and 1966...
stack used between 1965–66, in which ejection seats were used as the primary form of escape for the astronauts who flew on the ten Gemini
Project Gemini
Project Gemini was the second human spaceflight program of NASA, the civilian space agency of the United States government. Project Gemini was conducted between projects Mercury and Apollo, with ten manned flights occurring in 1965 and 1966....
missions.
The MLAS concept was dropped with the transformation of the CEV into the MPCV, and the switch of the launch vehicle from Ares I (with its perennial underperformance) to Delta IV-Heavy or SLS.
July 2009 test launch
A Max Launch Abort System test vehicle was launched July 8, 2009, at 6:26 a.m. EDT. The test vehicle weighed over 45000 lbs and was over 33 feet (10.1 m) tall.The test vehicle was different from the actual system in many ways. The main difference is that the four propulsion rockets were not located in the forward fairing, but in a boost skirt located at the bottom of the test vehicle. The rockets in the fairing were represented by geometric dummies. The propulsion thrust was not balanced between the rockets by a manifold system, contrary to what is foreseen with the actual system.
See also
- Boilerplate