The two modules that will fly NASA’s first solo Orion flight into lunar orbit and back are going through standalone testing in the lead up to becoming a mated spacecraft. The Crew and Service Modules for the Exploration Mission-1 (EM-1) flight are being assembled and tested by Orion prime contractor Lockheed Martin in the Operations and Checkout (O&C) Building at the Kennedy Space Center (KSC) in Florida.
The integrated Service Module joining the European Service Module (ESM) with the Crew Module Adapter (CMA) was powered up as a unit for the first time on February 14 to begin a last set of tests before it is ready to mate with the Crew Module. The last pieces due for the Crew Module arrived and are installed, so it can finish its pre-mate testing.
Once the modules are mated to form the in-flight EM-1 Orion, several weeks of pre-launch closeouts will also serve to get the spacecraft ready for space environment tests at Plum Brook Station in Ohio later this year.
Service Module initial power up on Valentine’s Day
Following a few months of work joining the ESM and CMA to form the EM-1 Service Module, the integrated unit was powered up for the first time on February 14. “It was about six o’clock in the afternoon when we actually powered up the first PDU (Power Data Unit),” Jules Schneider, Lockheed Martin Orion Assembly, Test, and Launch Operations (ATLO) Director at KSC, said in an interview the next day. “We’re into powered-on testing as we speak.”
“You’ve got to power up the avionics system and I believe we do the big elements like the PDUs and the big avionics components one at a time and then we load the software,” he added. “We have the active thermal control loops loaded and running so we can cool everything as we’re powered up.”
“Prior to actually applying the power we end up loading PGW (propylene, glycol, and water mixture), which is the coolant, and the R134a (refrigerant) we use from the ground side to cool everything,” Scott Wilson, NASA’s Production Operations Manager for the Orion Program, explained in the same interview. “Like Jules said that lets us bring up the active thermal control, which you need to run all the avionics racks.”
For this round of testing, the Service Module is connected to ground support equipment that provides services from currently unconnected systems inside and outside the SM. “We have a full suite of what we call electrical ground support equipment, EGSE, and we have I call them racks, they’re large cabinets full of different electronics and they represent different elements of the system, both on the ground side and the CM (Crew Module) side,” Schneider said.
“It basically simulates both the crew module as well as any of the systems we don’t have installed, like solar arrays today,” Wilson added. “So the racks, for instance, simulates the power the solar arrays would provide. There’s many racks that simulate the crew module itself and then there’s couplers to antennas and things like that when we get into RF (radio frequency) testing and phased array testing, those kind of things.”
Also called initial power-on (IPO), powering up the systems was in preparation for a functional checkout of the module. “The power up procedure only runs for about 36 hours, I think all you’re doing there is again, turning everything on and loading all the software and making sure you’re seeing nothing strange and things look nominal,” Schneider explained. “Then we actually have a series of thirteen functional tests that we’re going to run over the next three weeks to check out different subsystems and components that are a part of the Service Module.”
Prime contractor Lockheed Martin assembles and tests Orion vehicles in the O&C Building for launch. The Crew Module and Crew Module Adapter elements are delivered as bare structures that Lockheed Martin assembles and integrates into working spacecraft modules.
The ESM is assembled and integrated by Airbus Defence and Space in Bremen, Germany. Arrival in Florida starts final assembly of the three elements; once complete, the spacecraft is turned over to NASA at KSC for launch processing on-site.
The EM-1 mission is the second test mission in a three-flight development sequence as a part of the Orion Program’s Design, Development, Test and Evaluation (DDT&E). The Crew Module was the only working version that flew on the first Orion test flight, Exploration Flight Test-1 (EFT-1) in December, 2014, where it flew most of the four-hour mission attached to a passive, mass simulator of the Service Module and the upper stage of the Delta 4 Heavy launch vehicle.
This second flight spacecraft adds a working Service Module; the first flight ESM and CMA enables Orion to fly solo for the first time. The flight plan for Orion on EM-1 is to enter a Distant Retrograde Orbit (DRO) of the Moon on a flight that should last at least four weeks, maybe longer.
“We’ve got a long way to go,” Schneider noted. “We’re about a quarter of the way through the schedule that started when the ESM showed up and culminates with us delivering the integrated Crew and Service Module out of the O&C Building. We’re about a fourth of the way through that processing plan.”
Service Module road to IPO
The ESM, Flight Model-1, arrived at KSC in early November, kicking off a dense, year-long schedule of work to get the EM-1 Orion vehicle ready to handover to NASA’s Exploration Ground Systems (EGS) for launch preparations. A week after its November 8 arrival, the ESM and CMA were mated in the lift station, one of several work areas in the O&C Building for processing Orion hardware.
“We had a few challenges when you put the two surfaces together, mating up all the holes, and we worked through those challenges but that was not to be unexpected when you have two structures with lots of things hanging on them,” Wilson said. “So it took a little while to get everything aligned physically.”
“Then we go into the clean room where we weld the tubes that interface between the ESM side and the CMA side for the fluid systems, the various different propulsion and ECLSS (Environmental Control and Life Support System) systems,” Schneider explained. “Then like we do with all of our tube welds we have to do a structural test of those welds, so after the clean room we go into the proof test cell and we perform a proof test of all those tube welds and we do pre and post NDE (non-destructive evaluation) on those welds and a leak check of all those joints as well.”
“I think all the welding work went very well in the tubes, no real issues there,” Wilson said. “Proof test went really well.”
The welds were X-rayed after they were performed and then again after proof test. “The first ones you do are looking to make sure you’ve got a good weld,” Schneider said. “Yeah, you don’t have any porosity or concavity,” Wilson added.
“On the post-proof NDE, you’re looking to see if there were any undetectable flaws that grew during the pressure testing that you would now detect,” Schneider continued. “But we didn’t get any of those, so we’re in good shape,” Wilson again added. “We use digital X-ray, by the way, which is a good advanced technology.”
Following the proof test and post-proof NDE, the module was taken back to the lift station to close out all the inside connections. “We went back into the lift station primarily because the lift station gives us really good access,” Schneider noted.
“It’s got that platform that gives us 360-degree access on the exterior and that’s when we reinstalled PDUs S1 and S2 because they had come back from their repair or rework, we reinstalled them. There’s a whole bunch of I’ll call them ‘cats and dogs’ kinds of things that we had to clean up like there’s multi-layer insulation (MLI) that we had to go in and finalize.”
One of those was installing some additional components on the CMA part of the Service Module. “There’s a couple of phased-array antennas that hang on the aft walls of the CMA and then the star trackers and the OpNav (Optical Navigation) camera are part of an assembly we call the ‘optical bench’ and that hangs off of the aft end of the aft walls of the CMA, as well,” Schneider said.
“That platform in the lift station gives us really good access to be able to install those things, and then we have to mate up all the electrical harnesses to those elements, do all of that testing.”
Schneider and Wilson provided an overview of the intricacies of some of the MLI and heater close outs the team completed in the lift station. “There’s a lot of insulation that once you finish all those harness routings and component installations, there’s MLI that gets over the top of them,” Wilson said. “And you know once you close things out like that for flight you got to take a bunch of pictures and document all that stuff,” Schneider added.
“The other part that’s been a lot of work, too, has been up on the top part of the Service Module and the top part of the CMA, is heater closeouts and heater installations,” Wilson also noted.
“The more tedious work, actually, that happened in that phase is on the inside of the CMA,” Schneider added. “We have an internal access platform set or kit that we install that allows folks to get on the inside of the CMA and also access the forward end of the ESM.”
“There’s a bunch of tanks up there that get MLI closeouts, all those tubes that we welded in the clean room all have to get heaters and temp (temperature) sensors integrated to them,” he explained. “You’re laying on your stomach reaching down. It’s kind of tedious, difficult work and you can’t have a lot of people in there at one time.”
“So it’s kind of tedious and difficult work and then you’ve got to wrap all the heaters with special tape and it’s…painful,” he added.
The module was then moved to the Avionics, Power and Wiring Station in early February for IPO and functional testing.
NASA and Lockheed have been building the American modules in the O&C Building for a while, but the team performing this first Service Module integration brought together both NASA, the European Space Agency (ESA), and their respective contractors.
“It’s interesting because it’s the first phase of work we’ve had where you’ve got the international team, too,” Wilson noted. “And so you’ve got both NASA and Lockheed folks and Lockheed is normal contractor supporting like we’ve always had, but we also now have ESA and Airbus and TAS-I (Thales Alenia Space Italy) and Dutch Space (now Airbus Defence and Space Netherlands) all in the mix, too, doing their work and interleaving all of that in the workflow. It potentially could have been a challenging time having that many different entities working [together] but it’s gone very, very well.”