MLAS abort test takes place as Ares I-X moves into stacking operations
The Max Launch Abort System (MLAS) has successfully carried out a pad abort test launch from NASA’s Wallops facility on Wednesday morning. Meanwhile, back at the Kennedy Space Center, the Ares I-X test vehicle is set to begin stacking operations inside the Vehicle Assembly Building (VAB) on Wednesday evening.
The Max Launch Abort System (MLAS) is an evolution of two of the original three LAS concepts studied by Constellation. The MLAS concept combines the boost protection cover of the service module mounted escape system with the command module mounted motors.
MLAS study was kicked off back in June, 2007 – with a roadmap planned out until 2009. The project has been run from the NASA’s Exploration Systems Mission Directorate (ESMD) under special managerial funding, separate from Constellation funds. NASA’s Langley center has been leading the design of the system.
Grown out of the hand drawn sketch by Mike Griffin, dated March 22, 2006, the MLAS concept has been gaining momentum as a solution to unspecified issues relating to the traditional tower abort system.
The design of MLAS has changed several times during its development, gaining fins for stability during later cycles, becoming more in line with another hand drawn sketch by former Constellation head Scott “Doc” Horowitz – as seen in one of two MLAS presentations acquired by L2 – over a year after Mr Griffin’s conceptual design.
The final version of the MLAS flight test vehicle weighs in at over 45,000 lbs and is over 33 feet tall.
The ‘bullet’ aerodynamic cover houses four Mk 70 Terrier solid motors that are used to power the abort. Two orientation parachutes are attached to the top of the fairing to re-orient the vehicle with the blunt heat shield into the wind and to aid in fairing separation.
The pad abort test proper began seven seconds after burnout of the solid motors, as the vehicle rose into the Virginia morning sky at 6:25am local time.
Witnesses of the launch claim the vehicle rose on a stable flight path, before reorientation and further stabilization, followed by crew module simulator separation from the MLAS fairing, and parachute recovery of the crew module simulator. All events appear to have been ably completed without issue.
“The test demonstrated a number of things: the unpowered flight of the MLAS along a stable trajectory; reorientation and stabilization of the MLAS; separation of the crew module simulator from the abort motors; and stabilization and parachute recovery of the crew module simulator,” wrote NASA PAO’s Rebecca Powell.
“An important objective of the test was to provide the workforce of NASA’s Engineering and Safety Center, or NESC, with experience in flight testing a spacecraft concept.”
Other tests are planned for MLAS, including a high altitude abort, which will involve the fairing being released immediately after abort is called to allow the Command Module Reaction Control System (RCS) to stabilize the vehicle for entry.
If Ares I survives the ongoing reviews, and MLAS is chosen as a successor to the current LAS, a four piece fiberglass fairing will cover the Command Module to create a flush edge on the Ares I launcher.
See original article outlining MLAS in 2007 – six months before any other media noted the system’s existence:
The four segment test vehicle is scheduled to begin stacking operations on its Mobile Launch Platform inside High Bay 3 of the VAB on Wednesday evening, following the arrival of the aft booster section into High Bay 4 earlier this morning.
“The Aft Booster will be brought over to HB4 this morning after peak traffic. Will start stacking ops (clears) at approx 1630hrs tonight,” noted Wednesday processing information on L2. “Ares I-X (VAB HB-3/4) (RPSF) (Pad-B) RPSF: Transport Aft Booster to VAB is scheduled for today.
“VAB HB-4: Forward Assembly/Interstage mate to 5th Segment Simulator (5SS) was completed yesterday. Post ops in work. DFI Config2 GSE interconnecting cable mates in work. Stack-1 Modal test pre-ops continue.
“US-7: Install 2 Bus Couplers and 1 Temperature Sensor in work. US-6: Install upper stage camera and video test in work.
“VAB HB-3: Receive Aft Booster and mate to MLP is scheduled for today.”
Currently scheduled for a September 17 launch, it is likely the additional requirements of “loads analysis” on the vehicle during the upcoming stacking operations will threaten to push the launch date into October – which has been expected by engineers as of last year.
The reason for the additional testing on the stack relates to threats to the vehicle’s Flight Termination System (FTS) during periods of Thrust Oscillation as the vehicle launches uphill.
However, there has also been an undocumented note of concern relating to FTS risk associated with vibrations at Max-Q – which would be more serious, given the earlier phase of ascent the vehicle will pass through the period of maximum aerodynamic pressure, and thus a potential constraint to gaining the required range waiver from the US Air Force.
“USS (Upper Stage Simulator): Continue with Aft Booster stacking ops but we still have outstanding loads analysis results pending. We will create a checkpoint prior to the stacking of Stack-1,” added associated notes on Wednesday.
“If analysis results are good we will then proceed with the remainder of stacking. This will prevent a situation of a possible de-stack to correct any issues and avoid future delays.”
Ares I-X engineers will use the data gained from the periodic testing on the vehicle’s integrity during stacking operations to hopefully eliminate such concerns.
L2 members: Documentation – from which the above article has quoted snippets – is available in full in the related L2 sections, now over 4000 gbs in size.