NASA completes umbilical test for SLS Artemis 1 mission

NASA’s Space Launch System (SLS) rocket completed another milestone on its way to launch with… The post NASA completes umbilical test for SLS Artemis 1 mission appeared first on

NASA completes umbilical test for SLS Artemis 1 mission

NASA’s Space Launch System (SLS) rocket completed another milestone on its way to launch with the Umbilical Release and Retract Test (URRT). The URRT was performed on the rocket on September 19 while it stood in High Bay 3 of the Vehicle Assembly Building (VAB).

During the test, the swing arms and T0 umbilicals at the base of the rocket were commanded to retract from the vehicle as they will during a standard SLS launch countdown.

The test occurred on Mobile Launcher 1 (ML-1) and allowed ground teams to verify and validate the mechanisms, timings, and function of the umbilical release and retract system that will separate and move the arms — that support data and communications pathways as well as fueling ports for the upper stage — away from the SLS rocket and against the tower at launch.

The tower itself is built onto ML-1 and supports not only the swing arms and their data and fueling systems, but also the Orion capsule and Service Module with purge lines, data and communication paths, and access to the Orion vehicle for crewed missions.

This is the same Mobile Launcher that will be used for the Artemis 1 mission and other flights that use the Interim Cryogenic Propulsion Stage (ICPS). It was initially constructed for Ares I in 2010, but with the cancelation of the Constellation program, ML-1 was modified to be used with SLS Block 1 with the ICPS.

Following Artemis 3, NASA will move to a different launch tower, ML-2, that will support the launches of SLS Block 1B and its Exploration Upper Stage that replaces the ICPS.

A second Mobile Launcher is required as a modification of ML-1 was not feasible because it would result in more than two years between SLS launches.

Regardless of which ML is used, the SLS rocket has a variety of umbilicals that are attached to different parts of the ML tower.

The first SLS standing tall on its Mobile Launcher ahead of its Umbilical Release and Retract Test (URRT) — a critical step toward launch. (Credit: NASA/Frank Michaux)

At the bottom of the rocket sit the Aft Skirt Electrical Umbilicals (ASEU), which provide communication to the Solid Rocket Boosters (SRBs) and communicate with the Launch Release System to issue the final release command.

Also connected to the aft skirt are the GN2 Purge Umbilicals, which are used to purge the SRB aft skirts.

Both of these were not involved in the URRT.

A final set of ground umbilicals at the base of SLS are the two Tail Service Mast Umbilicals (TSMUs). These service masts are the primary connection to fuel the rocket’s Core Stage with liquid hydrogen coming from one of the TSMUs and liquid oxygen from the other.

They are located on the opposite side of the rocket in relation to the launch tower. The TSMUs were involved in the URRT.

Moving up the rocket, the Core Stage Inter-Tank Umbilical (CSITU) is connected to the Core Stage intertank between the hydrogen and oxygen tanks at a height of 42.7 meters.

This arm is used to vent gaseous hydrogen from the Core Stage, provide a data connection, and supply pressurized gases and power.

The Core Stage Forward Skirt Umbilical (CSFSU) is above at 54.9 meters between the first and second stages right above the oxygen tank. It is used to provide GN2 (gaseous nitrogen) to the SLS core stage.

Six meters above that is the Vehicle Stabilizer System (VSS). This is used to stabilize the core stage during rollout and countdown and will drop down right before liftoff.

A side view of SLS with the SRB cable trays exposed and additional, temporary wiring for the modal test sequence visible. The cable trays will eventually be closed out and covered for flight. (Credit: NASA/Frank Michaux)

Above that, at the 73.2-meter level, is the support umbilical for the second stage and the RL10B-2 vacuum engine. This is the Interim Cryogenic Propulsion Stage Umbilical (ICPSU) and provides liquid oxygen and liquid hydrogen fueling support for the upper stage as well as electrical connections and pneumatics.

Even higher, next to the Crew Access Arm sits the Orion Service Module Umbilical (OSMU), which was also included in this test. It provides liquid coolant and purge air for the environmental control system and the Launch Abort System.

In this test, the OSMU was connected to the Orion Mass Simulator at the top of the stack. The actual Orion was purposefully left out of this test sequence to allow as much time as possible for the rideshare CubeSats that will fly with it to be readied for flight.

All of the swing arm umbilicals run on different forms of detachment mechanisms, using winches, wire rope lanyards, or even breakpoints. Most of them are not only built with one but two or even three different mechanisms that can detach the umbilical.

None of the swing arms use pyrotechnic separation systems as previous NASA rockets have.

The mechanisms to release the umbilicals will be triggered by the same signal used to give the start command to the two SRBs to make sure the rocket has a clear path upwards when the boosters ignite since the launch cannot be aborted after that command is given.

Numerous other elements of ML-1 and its tower’s fueling, communication, data, and associated systems were tested at Launch Complex 39B prior to SLS Artemis 1 stacking in an effort to find issues that could be corrected before first flight operations and prove out the ground architecture for SLS.

Part of that pad test simulated the countdown and an Umbilical Arm Simultaneous Retract Test involving the ICPSU, CSFSU, and CSITU.

With the URRT now behind them, teams will now prepare for the full stack’s Integrated Modal Testing (IMT). The rocket will be tested with mechanical shakers to check its structural integrity and resonance frequency.

The SLS Mobile Launch, a hold-over from Constellation, on a modified Apollo-era crawlerway transporter arrives at LC-39B for testing. (Credit: Stephen Marr for NSF/L2)

This will be one of the last tests with the Orion Mass Simulator before it will be de-stacked and replaced with the Orion spacecraft and service module for the Artemis 1 mission.

The SLS rocket is currently planned to roll later this year to Launch Complex 39B for a full Wet Dress Rehearsal. After that, it will be brought back to the VAB for final checkouts and ordnance installation.

As of Tuesday, September 21, NASA is still holding to a public target of the end of the year for Artemis 1’s launch; however, early 2022 is a far more likely launch target at this time.

(Lead image: SLS in VAB High Bay 3 ahead of its Umbilical Release and Retract Test. Credit: NASA/Frank Michaux)

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NASA VIPER rover and Astrobotic Griffin lander select moon landing site for 2023

The NASA VIPER rover – a precursor mission to human landings in the south polar… The post NASA VIPER rover and Astrobotic Griffin lander select moon landing site for 2023 appeared first on

NASA VIPER rover and Astrobotic Griffin lander select moon landing site for 2023

The NASA VIPER rover – a precursor mission to human landings in the south polar region of the Moon, and a mission started in 2019 under the Commercial Lunar Payload Services program – has had its landing site selected for its 2023 mission. The rover, known as the Volatiles Investigating Polar Exploration Rover, is now scheduled to land west of Nobile Crater in the lunar south polar region sometime in late 2023 after its launch aboard a SpaceX Falcon Heavy rocket.

This mission, costing $660 million, is one of several that will launch to the Moon in the next two years and is notable for being the first NASA rover to launch as a customer aboard a commercial lander. 

The golf cart-sized VIPER rover will be mounted onto a Griffin lunar lander built by Astrobotic, a Pittsburgh-based company developing various lunar spacecraft that can carry payloads into lunar orbit or onto the lunar surface. After landing, VIPER will roll out onto the lunar surface with the help of a pair of ramps mounted on the lander and conduct checkouts before starting its surface mission.

The Griffin/VIPER combination is targeted to land at one of 11 “regions of interest” in the south polar region of the Moon identified in scientific papers as being favorable for hosting permanently shadowed regions (PSRs) with water ice present under the surface, while also being safe for spacecraft to land and generate power through solar panels while outside of the PSRs.

This is in sharp contrast to past lunar rover missions like Lunokhod 1 and 2 and the Lunar Rover driven by astronauts on the Apollo J-class missions, which explored areas of the Moon closer to the equator.

The south polar region of the Moon is now proven to contain water ice, as a result of observations by the Indian Chandrayaan-1 probe in 2008 and a 2009 NASA mission known as LCROSS that found water ice in the ejecta generated by a planned Centaur rocket stage crash into a permanently shadowed crater on the lunar South Pole. Later an instrument on the Lunar Reconnaissance Orbiter called Diviner generated key data that informed scientists about which regions of the Moon would have permanently shadowed regions suitable for water ice to form and remain intact.

The mission team needed to satisfy four criteria: available sunlight for solar power generation, earth visibility for communications, data indicating the presence of water ice in the area, and terrain suitable for rover driving. After extensive study, NASA has announced Nobile Crater as the VIPER landing site. Nobile was one of the 11 “regions of interest” noted above as being identified by scientists as being suitable for exploration in the south polar region of the Moon.

As NASA associate administrator for science Thomas Zurbuchen stated, “Once on the lunar surface, VIPER will provide ground truth measurements for the presence of water and other resources at the Moon’s South Pole, and the areas surrounding Nobile Crater showed the most promise in this scientific pursuit.”

Data visualization of the region west of Nobile Crater which has been selected as VIPER’s landing site – via NASA

After landing west of Nobile Crater, VIPER is scheduled for a 100-day prime mission to drive around the region. VIPER’s task is to map the region’s water ice deposits and test how accessible the water is, and the nature of the ice, the regolith, and shadowed areas. Though taller and heavier than the Spirit and Opportunity Mars rovers, VIPER’s driving speed is twice as fast as the MER rovers, which will help it cover longer distances more quickly.

Griffin/VIPER Updates
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  • The VIPER mission will need to survive brutal extremes of temperature and terrain in the south polar region. Since the Moon doesn’t have any substantial atmosphere, high temperatures can be up to 127 degrees Celsius.

    In comparison, lows in the polar regions can get down to -223 degrees Celsius in permanently shadowed regions, one of the coldest areas in the entire solar system. In the polar regions, the Sun is always near the horizon, and the rover will need to avoid long stretches in shadowed areas where it can freeze. Several layers of insulation and heat pipes will help VIPER survive.

    VIPER is designed to routinely handle slopes up to 15 degrees, and can even drive on slopes up to 30 degrees if needed, which will be very helpful with the polar terrain, which is pockmarked with craters and can reach elevations of 8000 feet above or below the mean datum level of the Moon. VIPER is designed to survive up to 4 Earth days of total darkness, so it will need to climb up steep slopes to high elevation areas where the night only lasts up to 4 days, compared to 14 Earth days for most of the Moon.

    VIPER is equipped with three instruments and a drill. The NSS (Neutron Spectrometer System) is designed to detect areas below the surface that could have ice deposits. Once NSS finds an area where further investigation is warranted, the drill known as TRIDENT (The Regolith and Ice Drill for Exploring New Terrains) will collect soil from up to 1 meter below the surface. 

    The Griffin Lunar Analog Model (left) featuring ramps for the VIPER rover alongside the Peregrine Structural Test Model (right) – via Astrobotic

    TRIDENT is developed by Honeybee Robotics, using experience from its tools used to drill rock on Mars, starting with the Spirit and Opportunity rovers. Other instruments are developed at the Ames Research Center or the Kennedy Space Center, while the rover hardware is designed at the Johnson Space Center. The mission itself will be managed and commanded from the Ames Research Center in Mountain View, California.

    Once TRIDENT gathers its soil cuttings, the MSolo (Mass Spectrometer Observing Lunar Operations) and NIRVSS (Near Infrared Volatiles Spectrometer System) will analyze these cuttings for their composition and concentration of resources. Scientists expect to not only look for water, but also carbon dioxide, ammonia, and methane with these instruments.

    The data VIPER gathers will be added to information from other missions to produce the first global map of water resources on another world. In addition, they will inform efforts by Artemis astronauts to use these resources to make rocket fuel, drinking water, and other essentials and make human habitation on the Moon sustainable.

    Beginning with the Peregrine-1 lander mission next year, NASA will fly VIPER’s instruments to the lunar surface to test their performance before they fly on the rover itself.

    Missions like Peregrine-1, VIPER, other CLPS missions, as well as missions flown by other countries, will start a new era of lunar exploration that is structured to be more sustainable and involve many more commercial and international parties than the previous era of lunar exploration during the Cold War decades of the 1960s and 1970s.

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