Ten month schedule to ready SLS for Artemis 1 launch after Core Stage arrives at KSC

NASA’s Exploration Ground Systems (EGS) program is looking at a wide range of forecasts for… The post Ten month schedule to ready SLS for Artemis 1 launch after Core Stage arrives at KSC appeared first on NASASpaceFlight.com.

Ten month schedule to ready SLS for Artemis 1 launch after Core Stage arrives at KSC

NASA’s Exploration Ground Systems (EGS) program is looking at a wide range of forecasts for when they can complete testing necessary to be ready to launch Artemis 1. The Core Stage of NASA’s first Space Launch System (SLS) vehicle arrived at the Kennedy Space Center and was moved into the Vehicle Assembly Building (VAB) on April 29 to prep for stacking with the new launch vehicle’s Solid Rocket Boosters, which are already in place on the Mobile Launcher in High Bay 3.

Approximately six months of work is anticipated to finish assembly and complete a long series of tests and checkouts of SLS and the Orion spacecraft it will send to the Moon, but current forecasts of this first-time integration work estimate closer to ten months to complete the necessary operations. After the vehicle is put together, weeks and weeks of testing to make sure SLS and Orion are properly talking to each other, as well as the EGS ground infrastructure, will follow.

Much more time needed for testing than stacking

The SLS Core Stage was the final Artemis 1 component to ship to KSC, and its long-awaited arrival allows the EGS and prime test operations and support contractor Jacobs to now put the whole vehicle together. Once final preparations are completed, the Core Stage will be mated to the SLS Boosters, which will allow the vehicle’s upper stage and eventually the Orion spacecraft to be put in place.

When the vehicle, ground systems, and launch team are ready to launch will depend on the progress of the months of integrated testing ahead.

Recent schedules showed the remainder of work to reach launch readiness extending for ten months once the core stage arrived. That time includes six months of operations to the “work to” launch readiness and four months of “risk factor”. The “work to” launch readiness date, which would still have to synchronize to a lunar launch window, is currently early-November 2020. With risk factored in, a date of early-March 2022 is derived.

“What I would tell you is that, from that standpoint, we fully expect it to take ten months to get everything completed and to get the vehicle launch ready,” Cliff Lanham, NASA Senior Vehicle Operations manager for EGS at KSC, said in a recent interview.

The majority of the 10-month timeline is taken up by the Integrated Testing and Check-Out (ITCO) of the connections between the spacecraft, launch vehicle, and ground systems after all the elements are mated. Some of that time includes special testing prior to this first flight of all the Exploration Systems Development division programs with Artemis 1.

There are two phases of ITCO in this first launch processing flow. When SLS is assembled for the first time, the launch vehicle will go through a first round of tests with an Orion mass simulator standing in for the spacecraft.

After an umbilical retract test and a special pre-Artemis 1 structural modal test, the Orion simulator will be removed and replaced with the Orion spacecraft. A second round of integrated testing will then take place with the fully assembled Orion-SLS flight vehicle.

Additional engineering tests and joint exercises with agency support centers around the country will then precede a roll out to Launch Complex 39B for additional engineering tests and a final Wet Dress Rehearsal. (WDR). After the WDR, the vehicle will be rolled back to the VAB for final pre-flight and launch preparations before returning to the pad for liftoff.

EGS and Jacobs started Artemis 1 launch processing last year; the SLS Boosters are currently fully stacked on the Mobile Launcher and the Orion spacecraft is being loaded with its flight commodities in the Multi-Payload Processing Facility (MPPF).

The Core Stage Green Run Hot-Fire that was completed on March 18 at the Stennis Space Center was the final major standalone development test for the program, and the stage departed the test facility early on April 22 in the agency’s Pegasus barge following a month of refurbishment. After arriving on dock at the Launch Complex 39 Turn Basin on the evening of April 27, the stage was offloaded from Pegasus and rolled into the low bay of the VAB on April 29.

Credit: Philip Sloss for NSF.

(Photo Caption: The heavily-charred base heatshield of Core Stage-1 inside the Pegasus barge at KSC on April 28. Following arrival at Kennedy the evening before, purge equipment was disconnected from the stage to clear the way for it to be rolled off the barge. Inspections of the heatshield thermal protection system (TPS) were deferred until after arrival at KSC since they weren’t needed for shipment from the Stennis Space Center and could be done in parallel with other work in Florida.)

Now that the Core Stage is in the VAB, the Artemis 1 vehicle can be fully assembled in High Bay 3.

The work:

“We will work in the Transfer Aisle of the VAB putting on our linear shaped charge, working on the Core Stage systems tunnel,” Lanham said. “Mating of the Core Stage and finishing of that work in the Transfer Aisle is a critical path. So once we get it up and onto the Booster stack, then we will go [through the] whole flow of mating the [rest of the] vehicle and then getting into that testing and getting to WDR. And that is our critical path [to launch].”

Some refurbishment work following the Green Run Hot-Fire was required before the Core Stage could be transported to KSC, such as on the Aerojet Rocketdyne RS-25 engines, but additional work on the thermal protection system (TPS) on the Core was deferred until after arrival. Some of that “traveled” work will be performed while the stage is horizontal in the Transfer Aisle of the VAB before it is ready to be lifted for mating to the Boosters.

“The TPS is a big part of what traveled work is and [is a big part of] the procedures that Jacobs and Boeing are working [on] in conjunction,” Nathalie Quintero, Boeing SLS Launch Operations Aerospace and Systems Engineer, explained. Quintero said inspections to determine what work needed to be done had started on the stage inside Pegasus after arrival at KSC even before the move into the VAB.

One of the traveled work tasks involves inspections of the base heatshield TPS. “We were going to try to evaluate that at Stennis, but our timeline there was shortened because we needed to get here to KSC. And with the refurb that the engine team had to do, they had to have primary access to the base heatshield area,” Michael Alldredge, NASA SLS TPS Subsystem Manager, said.

Credit: Philip Sloss for NSF.

(Photo Caption: NASA EGS and Jacobs teams move Core Stage-1 into the KSC Press Site parking lot during offload from the Pegasus barge and rollover to the VAB on April 29. The stage rolled off the barge aft end first but needed to roll into the VAB forward end first. The two pairs of self-propelled motorized transporters (SPMT) that made the move have six degrees of freedom and can make precise turns.)

“We [couldn’t] get in there from a time standpoint to do the in-depth analysis and post-test assessment that we wanted to get done, so that work will be performed here at KSC.”

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  • The remainder of the inspections and repairs to areas of the stage’s thermal protection system (TPS) will be completed at KSC, but with less weather disruptions inside the VAB versus outside in the B-2 Test Stand at Stennis; the foam inspections and repair work can also be done in parallel with other required work that needs to be done before the Core Stage can be mated to the Boosters.

    “The [TPS] work is being broken down into access constraints,” Alldredge explained. “Once you [mate the Core Stage] with the Boosters, [there are areas] you can’t get to. So the work is being prioritized such that we do the things that we have to do in the Transfer Aisle and then everything else I believe will go in [High Bay 3 after stacking].”

    Some of the pre-mate TPS work, Alldredge said, will include repairs to some areas of SOFI (Spray-On Foam Insulation) on the intertank to liquid hydrogen (LH2) tank flange area.

    Once the Core Stage is hard-mated to the Boosters, parallel activities from the integrated operations team will occur to simultaneously finish assembling the SLS hardware while preparing for both vehicle checkouts and the special Integrated Modal Test (IMT) later in the flow. “We bring in the Core Stage and mate it. Then we’ll get into modal [test] preps,” Lanham said. “We’ll install sensors and start cable routing, but also along those same lines we start bringing the stack together, if you will, with the hardware mates.”

    Getting the Core in place on the Mobile Launcher will also allow some Mobile Launcher umbilicals to be mated, which will help expedite powering up SLS and beginning checkouts. “The goal as we stack the Core Stage will be to get all the umbilicals mated as soon as possible to have that connectivity to get into testing and all the things that are going to come once we’ve successfully mated the arms,” said Andrew Shroble, Integrated Operations Flow Manager for Jacobs.

    “The Tail Service Mast Umbilicals (TSMU) will actually require internal access to the engine section to be able to vent the lines down before we actually mate the umbilicals. So that’s one of the first things that we do [after mating the Core Stage and the Boosters]. The Core Stage Intertank Umbilical, we’re able to swing that out and mate that as soon as possible. It doesn’t require internal access, so that’ll be something we look to do right out of the gate.”

    In parallel, stacking will continue, first with the Launch Vehicle Stage Adapter (LVSA). The LVSA will be bolted to the forward skirt of the Core Stage; that mated flange will then be closed out with foam. The LVSA will stay with the Core Stage in flight and has a frangible joint assembly on the top to separate the ICPS.

    After the LVSA is stacked, the Interim Cryogenic Propulsion Stage (ICPS) – currently in the MPPF where its attitude control system tanks will be filled with hydrazine – will be brought to the VAB and stacked. At this point, flight vehicle assembly will stop and the Mass Simulator for Orion will complete stacking for the first phase of verification testing along with the umbilical test and the Integrated Modal Test.

    “At that point we’ll have the stack that we’re going to use for modal,” Lanham said.

    Equally as important as the structural attachments between the launch vehicle elements are the electrical and data connections which allow the computers in the Core Stage to talk to the avionics in the Boosters. The SLS computer system in the Block 1 vehicle covers the Core Stage and the Boosters; the ICPS is a United Launch Alliance (ULA) product, derived from the Delta Cryogenic Second Stage (DCSS), which has its own, self-contained computer and guidance system that is standing by to take over control of the flight after the Core separates.

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    Starship SN15 moves to Tuesday attempt

    Following two successful Static Fire tests during the week, Starship SN15 was set to launch… The post Starship SN15 moves to Tuesday attempt appeared first on NASASpaceFlight.com.

    Starship SN15 moves to Tuesday attempt

    Following two successful Static Fire tests during the week, Starship SN15 was set to launch Friday afternoon. However, the hop was pushed to no earlier than Tuesday due to technical preparedness, specifically flight software – followed by a wait for acceptable weather. The test will take place amid ongoing groundwork for the push to orbit is taking place both at the Orbital Launch Site and elsewhere in Texas as a new dual-bay Raptor test stand nears completion.

    Starship SN15:

    Since arriving at the Suborbital Launch Site, SN15 has undergone several “risk reduction” tests ahead of firing up her trio of Raptors.

    That included the usual routine of proof testing the vehicle, filling and pressurizing the tanks with ambient, gaseous nitrogen before proceeding with cryogenic testing with liquid nitrogen.

    The roads were closed for additional testing late last week, although not for a Static Fire test. This time, the vehicle was loaded with Liquid Oxygen before a LOX Dump test, aimed at improvements relating to safing the vehicle ahead of and after flight, was completed.

    SpaceX SN15 Updates
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  • With limited opportunities to conduct weekend testing, that requires Highway 4 to be closed to the public, SpaceX opted to move the Static Fire attempt to Monday. A three engine test did occur just prior to 5pm local time.

    An eight-hour window was available for the opportunity to fire up the SN54, SN61, and SN66 Raptors, which was followed by a quick look data review. Occasionally, such reviews have found issues with one of the engines, requiring a swap out and repeat of the test in the following days.

    The potential of a recycle later in the day remained on the cards, given SpaceX likes to test the engine’s use of propellant from the Header Tanks.

    These small tanks are located at the top of the nosecone (LOX) and the middle of the vehicle (CH4 – Liquid Methane) and supply the engines for the flip and landing burn.

    However, Elon Musk tweeted the Static Fire was good and that they were preparing for launch later this week.

    It was yet to be confirmed if that concluded the test requirements, with another Static Fire noticed posted later on Monday for a Tuesday test.

    Then, with roadblocks in place, SN15 headed into another test cycle on Tuesday, resulting in a planned single-engine Static Fire test.

    All this testing is aimed at conducting another smooth flight and an attempt to nail a smooth landing. Pending acceptable weather, that attempt was to take place on Friday. A scrub was called, resulting in the launch moving to early next week. While the weather was the main watch item on the due, Elon Musk later noted the decision to call off the attempt was due to a flight software issue.

    All eyes will be on that key phase of the flight, with Starship having already proven and repeated numerous major milestones while only landing in one piece during the SN10 test. However, that was a hard landing, resulting in the vehicle exploding minutes later.

    Moving on from those initial series of test with SN8 through SN11, SN15 is the first vehicle to sport improvements ranging from the Thrust Puck to her avionics, and, importantly, the Raptor engines.

    Other improvements have not been revealed, although may include the Header Tank system, which, in total, would form a mitigation path to the issues suffered by previous Starship prototypes.

    Regardless, should SN15 suffer issues, SN16 is already being stacked in the Mid Bay. However, if SN15 nails the landing, the path forward becomes less clear, albeit even more exciting.

    As seen after the successful 150-meter hops of SN5 and SN6, SpaceX’s original plan to conduct a tag-team approach of repeating tests with these two vehicles was canceled. Instead, the program pushed forward to SN8 and the first high altitude test.

    Should SN15 complete all the required high altitude test objectives, SpaceX may repeat the test or push to a higher altitude. Elon Musk could even opt to switch to the involvement of Super Heavy, which may involve a booster-only flight, or the previously reported BN3 and SN20 orbital flight.

    Drive To Orbit:

    Starship’s early orbital ambitions have been previously mentioned in actual SpaceX documentation, as reported by this site and confirmed by the “that’s the goal” tweet from Elon.

    While the documentation noted “by July 1”, taking the usual overly optimistic timeline that has often been associated with Starship milestone targets, the potential of an orbital flight in the summer remains an amazing prospect.

    Starship SN20 during entry-interface – via Mack Crawford for NSF/L2

    Numerous pieces of the puzzle need to fall into place. However, all those pieces are currently being worked.

    Firstly, the requirement of covering the entire windward side of Starship in Thermal Protection System (TPS) tiles has seen incremental increases in the TPS patches seen on the flight prototypes, with SN11 hosting a record number of tiles.

    Over at the Production Site, Mary (@bocachicagal) has photographed sections completely covered in tiles.

    New Section inside the Production Tent covered in TPS – via Mary (@bocachicagal) for NSF.

    Secondly, the “blunt nosecone”, which was then surrounded by a test cage, has been rolled out to the Launch Site, allowing for stress testing.

    The goal will be to use the test rig to impart forces on the nosecone while pressurized. This will mimic how the nosecone performs under the aerodynamic stresses of heading uphill on an orbital mission.

    Thirdly, Super Heavy and its launch site.

    The Orbital Launch Site is a hive of activity, with work ranging from the installation of large GSE (Ground Support Equipment) tanks to continued work on the launch mount and launch and integration tower.

    The latter has now started to rise into the air next to the mount, which is yet to receive its launch table.

    When finished, the tower will be the tallest structure in the region, at nearly 152 meters — towering over the 120 meter tall, fully integrated Starship/Super Heavy stack. The Tower will eventually host a crane and, as crazy as it initially sounded when Elon revealed it, arms designed to catch the returning booster.

    SpaceX often conducts testing before all of the infrastructures is in final configuration, meaning the launch mount and table, along with the tower structure, could be enough for the initial test launch.

    While the BN1 Super Heavy prototype was only a pathfinder, SpaceX opted to scrap it before taking it to the Suborbital Launch Site for transportation and prop load testing.  BN1 has since been cut into sections and sent to the scrap yard.

    With Super Heavy now set to be stacked with the LOX and CH4 tanks in the reverse order to BN1’s configuration, SpaceX appears to be potentially creating a Test Tank version of the Super Heavy, with BN2 and BN2.1 sections spotted by Mary (@bocachicagal).

    While it is not yet clear what the plan is for BN2 and BN2.1, they will pave the way for the first fully stacked flight Super Heavy, BN3.

    BN3 has already been seen in sections at the Production Site and is likely to begin stacking in the High Bay in the very near future.

    The current plan is to use this booster to fly Starship SN20 – already in production – on the orbital mission, although Starship milestone planning is constantly under review per vehicle assignments.

    Questions also remain on how many Raptors BN3 will require to conduct the orbital mission. The full suite of 28 Raptors won’t be required and would not be desirable.

    Elon has previously noted the Super Heavy test launch will use fewer engines as a mitigation against the likelihood a test mission would result in the loss of the vehicle. The Raptors are the most expensive element of the vehicles.

    Regardless, SpaceX Starbase (Boca Chica) will have a great demand for Raptor stock this year. Production of the engines is understood to be close to or above the SN100 range. However, they have to complete test firings at the McGregor test site before they are sent on the “RaptorVan” down to the Production Site.

    Raptor testing capacity has grown over recent years, with the addition of numerous test stands, including the conversion of the original stalwart Falcon 9 tripod stand, which now hosts vertical Raptor testing.

    The Tripod Stand, now testing Raptor engines – via Gary Blair for NSF/L2

    Elon Musk has previously noted that testing Raptor on vertical stands provides additional benefits.

    Raptor engines – including the first two Raptor Vac (RVac) units – also undergo testing in two horizontal bays, located in an area of McGregor that will soon have another Raptor test stand as a neighbor.

    The new Raptor stand has an underground diverter, and each of the vertical test bays will be available for testing both sea-level and vacuum-optimized Raptors. It is nearing completion at pace.

    View this weekend of the new Raptor Stand – via Gary Blair for NSF/L2

    From being a bare patch of grass just a few months ago, NSF’s Gary Blair in the L2 McGregor section – a local who flies past the test site at around 3,000 feet AGL – photographs show the final preparations on the new stand includes the installation of the large pieces of the flame diverter into what is a deep flame trench.

    With this increased test capacity, SpaceX will be able to run numerous numbers of Raptors through McGregor each week, catering to the demands of Super Heavy and Starship.

    Notably, SpaceX’s Modus Operandi is to return their vehicles, with Starship being a rapidly – and fully – reusable launch system. As such, Super Heavy and Starship will be aiming to return their Raptors for additional flights.

    For live updates, follow NASASpaceFlight’s Twitter account and the NSF Starship Forum Sections.

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    The post Starship SN15 moves to Tuesday attempt appeared first on NASASpaceFlight.com.

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