ML-2 Updates and Discussion

[KWC]

The FY26 PBR cancels ML-2.

NASA will close out Mobile Launcher-2 development, as ML-2 will not be needed to support SLS due to the orderly shutdown of the SLS Block 1B upgrade. NASA proposes to use previously appropriated unobligated balances to support the termination of these activities, including but not limited to, ongoing administration, oversight, and monitoring

[Pg. EXP-19 / Sheet 45]

what a shambolic waste of time and money... they are going to waste further millions just to cancel and this structure will be left rotting in the elements.
this current govt administration is truly a disaster.

I agree. SLS is a huge waste of money, and so canceling the program (ML-2 included) is a net positive for the U.S. Treasury. This would be an excellent example of not falling into the sunk-costs fallacy.

[pochimax]

Module 9

https://twitter.com/planetdeimos/status/1936151634003763457

[catdlr]

Mod-10

https://twitter.com/NASASpaceflight/status/1939017039089222129

NSF - NASASpaceflight.com
@NASASpaceflight
There's Mod-10, the final section for the SLS Mobile Launch 2 (ML-2), as required for the taller SLS Block 1B.

When lifted at the Parksite, it will begin a massive commissioning and system startup process.

The project is fully funded through the end of FY25

http://nsf.live/spacecoast

[catdlr]

Max Evens

https://twitter.com/_mgde_/status/1940499099532357709

NASA's Mobile Launcher 2 (ML-2), designed and built to support SLS Block 1B, completed stacking earlier this morning with its 10th and final module being lifted into place.

Now at its full height, work will continue on ML-2's internals and umbilical structures.

[pochimax]

From GAO report

The National Aeronautics and Space Administration (NASA) established
cost and schedule baselines for the ML2 project in June 2024. The cost
baseline is about $1.9 billion, and the schedule baseline is September
2027 for the delivery of ML2 from Bechtel, the prime contractor, to
NASA. Bechtel is working to a delivery date of November 2026, and its
contract was modified in March 2024 to incentivize an earlier delivery.
The schedule baseline does not include ML2 verification and validation
activities planned for after the delivery and prior to Artemis IV, which
NASA is tracking as the project’s top risk. To mitigate this risk, the
project plans to concurrently test the ML2 at the launch pad while
Artemis III hardware is processed in the Vehicle Assembly Building.
The project completed its critical design review. NASA and Bechtel
continue to assess the design implications of higher-than-anticipated
Artemis I launch-induced loads. The analysis is ongoing, so they have
not yet determined the full cost implications.
Construction on the ML2 structure is underway. Bechtel installed the first
tower module on the ML2 base in January 2025. Officials said there is
some schedule risk for remaining modules but NASA expects the
contractor to be able to support a November 2026 delivery of the tower.

Cost and Schedule Status
In June 2024, NASA established cost and schedule
baselines for the ML2 project based on a 70 percent joint
cost and schedule confidence level, as required by NASA
policy. The joint cost and schedule confidence level is an
integrated analysis of a project’s cost, schedule, risk, and
uncertainty, which indicates a project’s likelihood of
meeting a given set of cost and schedule targets. The
schedule baseline is September 2027 for Bechtel’s
delivery of ML2 to NASA. The cost baseline of
approximately $1.9 billion includes all prime contractor
efforts through delivery, as well as government furnished
equipment and government provided project
management and design support.
As of February 2025, NASA is working with the contractor
to support a November 2026 delivery date of the tower.
NASA modified its contract with Bechtel in March 2024 to
increase the available award fee and add a new award
fee component based on schedule milestones, among
other things. The change is meant to motivate earlier
delivery—the contractor will receive the highest single
schedule milestone fee payment if it delivers ML2 by May
2026, but will not receive a schedule milestone award fee
payment for the delivery if it is after November 2026. As
of February 2025, project officials expect the contractor to
be able to support a 2026 delivery, which is well in
advance of the project’s schedule baseline.
NASA’s top risk for ML2 is that there may be insufficient
schedule margin for ML2 verification and validation
testing between the Artemis III and IV missions. The
testing is largely planned to occur after Bechtel’s delivery
of ML2. However, some of the testing activities require
access to the launch pad or a modified Vehicle Assembly
Building and cannot take place until Artemis III launches.
Artemis III is planned for mid-2027, and Artemis IV is
currently planned to launch no earlier than September
2028. That schedule provides less than 18 months to
complete testing and first-time integration of ML2 with
SLS Block 1B and Orion. As of February 2025, project
risk documentation states that this testing could exceed
the time allocated by 8 months, which could delay the
Artemis IV mission. To mitigate this schedule risk, NASA
officials said that they plan to conduct simultaneous ML2
verification and validation at the launch pad while Artemis
III is processing in the Vehicle Assembly Building.

Design
NASA successfully completed both steps of the ML2
project’s critical design review: step one for hardware and
programmatic content in January 2024, and step two for
software and verification and validation plans in June
2024. As of February 2025, ML2 officials reported that the
design is complete for all but one subsystem.
NASA is currently tracking a top risk that an ongoing
loads analysis may drive cost and schedule growth.
According to project officials, the blast from the SLS
boosters during launch created loads, or forces, on the
ML1 structure that were higher than anticipated. NASA
and Bechtel are taking a three-phase approach to
examine the implications of the changed loads for the
ML2 design. They completed phase one and the
engineering design work for phase two, which identified
ML2 modifications needed to withstand the greater loads.
They then executed engineering design work to
implement those modifications.
Phase three is underway as of February 2025 and will
include engineering analysis of any calculations not
addressed in earlier phases. Project officials said that
phase three will be complete by the fourth quarter of
2025. According to NASA, the challenge with the loads
analysis has been keeping the construction work going
since the same employees are needed to support both
efforts. As of February 2025, the project is working on
estimates for the cost increases associated with the
phase three analysis and modifications.

Construction
Construction of ML2 continues, with work underway on
the base and assembly of portions of the tower occurring
on the ground. The tower modules will be installed, or
rigged and set on top of the base, after which NASA and
the contractor will work to install umbilical arms. These
arms will connect the tower to the rocket and spacecraft
to provide electrical support and propellant, among other
things. The contractor installed the first tower module on
the ML2 base in January 2025, within the timeframe for a
schedule milestone award fee payment. Project officials
reported that as of May 2025, another three modules
have been installed on the tower. They said that they plan
to install the final three modules after they complete their
construction and equipment installations by the end of
June 2025, which they said is within the targeted range
for one of the major milestones. Officials also reported
that the first of several umbilicals was installed on the
tower in May 2025, meeting the early schedule milestone
date.
Project risk documentation states that electrical
equipment deliveries are behind schedule, which could
affect plans for installing future tower modules. Project
officials said that electrical equipment is easier to install
prior to the rig and set of a module because it is easier to
access and install on the ground than other types of
equipment

[catdlr]

A time-lapse of the ML-2 buildup:

https://twitter.com/ENNEPS/status/1940708723753975875

[catdlr]

Cross-post:  Phillip Sloss reports on ML-2 on his weekly status video.

20:25 Other news and notes, starting with Mobile Launcher-2 umbilical tower being topped out
22:26 Artemis IV related GAO assessments of Mobile Launcher-2 and SLS Block 1B

https://forum.nasaspaceflight.com/index.php?topic=62717.msg2699410#msg2699410

[catdlr]

NSF Leadup post for the Forum Article by Justin Davenport:

Mobile Launcher 2 (ML-2), the launch tower and platform to be used by the Block 1B variant of the Space Launch System (SLS), recently had its tenth and final tower module stacked on July 2.

https://nasaspaceflight.com/2025/07/ml-2-final-module/

Module 10 will support the Orion crew access arm and related systems, and its installation brings the ML-2 tower’s height to 106 m. The overall ML-2 structure will be over 122 m tall and mass over 5,600,000 kg.

In other good news for the SLS and Artemis programs, Congress recently approved additional funding to preserve the Artemis IV and V missions, thereby maintaining SLS Block 1B and the rationale for using ML-2, which is only compatible with SLS vehicles from Block 1B forward.

By Justin Davenport.

https://twitter.com/NASASpaceflight/status/1945951026802286979

ARTICLE

 

[Tywin]

IF the SLS is cancel is the future, can this tower and pad, launch other big rockets?

[jstrotha0975]

IF the SLS is cancel is the future, can this tower and pad, launch other big rockets?

Sure, with modifications. The current tower for Block 1 SLS was originally built for the Ares I-X and was modified for SLS.

[DanClemmensen]

IF the SLS is cancel is the future, can this tower and pad, launch other big rockets?

Which other big rocket? ML-2 is part of a complicated system for stacking and launching. This system includes the VAB.  For SLS/Orion, the ML-2 is dedicated to a specific launch for many months. This is not consistent with the way other big rockets are launched. It's not clear that the ML-2/VAB system could ever support high cadence.

[jstrotha0975]

IF the SLS is cancel is the future, can this tower and pad, launch other big rockets?

Which other big rocket? ML-2 is part of a complicated system for stacking and launching. This system includes the VAB.  For SLS/Orion, the ML-2 is dedicated to a specific launch for many months. This is not consistent with the way other big rockets are launched. It's not clear that the ML-2/VAB system could ever support high cadence.

New Armstrong could use the current infrastructure for SLS. The VAB doors are 12 meters wide so NA could be 10-11 meters in diameter.

[Tywin]

IF the SLS is cancel is the future, can this tower and pad, launch other big rockets?

Which other big rocket? ML-2 is part of a complicated system for stacking and launching. This system includes the VAB.  For SLS/Orion, the ML-2 is dedicated to a specific launch for many months. This is not consistent with the way other big rockets are launched. It's not clear that the ML-2/VAB system could ever support high cadence.

New Armstrong could use the current infrastructure for SLS. The VAB doors are 12 meters wide so NA could be 10-11 meters in diameter.

That is the exactly rocket I was thinking...

[DanClemmensen]

IF the SLS is cancel is the future, can this tower and pad, launch other big rockets?

Which other big rocket? ML-2 is part of a complicated system for stacking and launching. This system includes the VAB.  For SLS/Orion, the ML-2 is dedicated to a specific launch for many months. This is not consistent with the way other big rockets are launched. It's not clear that the ML-2/VAB system could ever support high cadence.

New Armstrong could use the current infrastructure for SLS. The VAB doors are 12 meters wide so NA could be 10-11 meters in diameter.

That is the exactly rocket I was thinking...

If you were BO and NASA offered to give you ML-2 and VAB for free, requiring only that you maintain them, would you accept the deal? What analyses would you do first?

[russianhalo117]

IF the SLS is cancel is the future, can this tower and pad, launch other big rockets?

Which other big rocket? ML-2 is part of a complicated system for stacking and launching. This system includes the VAB.  For SLS/Orion, the ML-2 is dedicated to a specific launch for many months. This is not consistent with the way other big rockets are launched. It's not clear that the ML-2/VAB system could ever support high cadence.

New Armstrong could use the current infrastructure for SLS. The VAB doors are 12 meters wide so NA could be 10-11 meters in diameter.

That is the exactly rocket I was thinking...

If you were BO and NASA offered to give you ML-2 and VAB for free, requiring only that you maintain them, would you accept the deal? What analyses would you do first?

It is cost prohibitive to extensively modify existing infrastructure versus building new hardware. Converting ML-1 from Ares-1X for SLS resulted in unoptimized hardware locations that for example couldn't be relocated within the LUT to their new height on the SLS Block-1 rocket.

[DanClemmensen]

IF the SLS is cancel is the future, can this tower and pad, launch other big rockets?

Which other big rocket? ML-2 is part of a complicated system for stacking and launching. This system includes the VAB.  For SLS/Orion, the ML-2 is dedicated to a specific launch for many months. This is not consistent with the way other big rockets are launched. It's not clear that the ML-2/VAB system could ever support high cadence.

New Armstrong could use the current infrastructure for SLS. The VAB doors are 12 meters wide so NA could be 10-11 meters in diameter.

That is the exactly rocket I was thinking...

If you were BO and NASA offered to give you ML-2 and VAB for free, requiring only that you maintain them, would you accept the deal? What analyses would you do first?

It is cost prohibitive to extensively modify existing infrastructure versus building new hardware. Converting ML-1 from Ares-1X for SLS resulted in unoptimized hardware locations that for example couldn't be relocated within the LUT to their new height on the SLS Block-1 rocket.

Also, the VAB is 60 years old. It is made of steel and lives in a humid salty coastal environment. According to Jim, It is in need of maintenance and would be difficult to maintain even if it were pristine.

[Tywin]

The ramp is the value, I don't know if the VAB can be rebuild in that future contract.

[DanClemmensen]

The ramp is the value, I don't know if the VAB can be rebuild in that future contract.

You proposed to use ML-2 for New Armstrong. I am unclear as to how this would work, so I asked you for clarification. How does this relate to "the ramp"?

[Tywin]

The ramp is the value, I don't know if the VAB can be rebuild in that future contract.

You proposed to use ML-2 for New Armstrong. I am unclear as to how this would work, so I asked you for clarification. How does this relate to "the ramp"?

Well I hope the ML2 can work with the NA too...

[catdlr]

The Mobile Launcher for Artemis continues work with the last section now in place. Pipeing, electrical & hydraulics are now being attached. The platform sits beside the VAB at NASA.

https://x.com/GregScott_photo/status/1950166091365314560