If the COVID-19 coronavirus pandemic affected people in 2020, then its negative effects were also paid forward to NASA as the agency worked to prepare critical hardware for humanity’s first return to lunar distance with a crewed vehicle in almost a half-century. Throughout much of this most challenging of years, the B-2 Test Stand at NASA’s Stennis Space Center (SSC) in Bay St. Louis, Miss., has played host to the Core Stage of the gigantic Space Launch System (SLS) that will launch Artemis-1 around the Moon, towards the end of 2021.
As the Core Stage was put through a punishing regime of eight functional and operational tests—collectively known as the “Green Run”—a pair of five-segment Solid Rocket Boosters (SRBs) for Artemis-1 reached the Kennedy Space Center (KSC) in Florida, as efforts intensified to devise concepts for a Human Landing System (HLS), establish the necessary international partnerships and name the astronauts who will play a pivotal role in getting humans back to the Moon later this decade.
Standing 212 feet (64.6 meters) tall, the SLS Core Stage arrived at Stennis from NASA’s Michoud Assembly Facility (MAF) in New Orleans, La., aboard the Pegasus barge in the second week of January, whereupon it was hoisted into the cavernous expanse of the B-2 Test Stand. Previously used for qualification tests of the RS-25 Space Shuttle Main Engine (SSME), the Common Booster Core (CBC) for the United Launch Alliance (ULA) Delta IV and the S-IC first stage of the Saturn V, the stand has a long and storied history extending back over five decades.
Within days of its arrival, the Core Stage was put through the first of eight Green Run tests to evaluate its functional and operational performance. The “Modal Test” utilized mechanized “shakers” to impart dynamic forces as a means of identifying bending modes to help validate vehicle models to operate the rocket’s Guidance, Navigation and Control (GNC) systems. However, the worldwide march of COVID-19 pushed Stennis into a “Level Four” posture on the scale of NASA’s pandemic response framework in March, with only personnel for essential activities relating to the safety and security of the center permitted to remain on site.
When crews returned to work in mid-May, systems were reactivated and checked out, both for the test stand the test control center. At the end of June, the second Green Run test—the “Avionics Test”—was successfully completed. The avionics, including the flight control computers and electronics, as well as a multitude of sensors which gather flight data and monitor the health of the Core Stage in flight, were powered-up and checked out.
The “Fail-Safes Test” of the Core Stage’s safety systems concluded in early July, followed by the “Propulsion Test” in early August to check for leaks and evaluate command-and-control operations for the Main Propulsion System (MPS) elements which directly interface with the four RS-25 engines.
But in addition to COVID-19, Mother Nature also impacted the progress of the Green Run. August brought a pair of exceptionally powerful natural predators in the menacing forms of Hurricanes Marco and Laura, which devastated the Caribbean Sea and threatened the Gulf Coast.
Work was temporarily suspended for a few days in late August as both the B-2 Test Stand and the Core Stage were secured until the storms passed. The fifth test concluded early in September and was classified as the final “functional” test, dedicated to evaluating the Core Stage’s Thrust Vector Control (TVC) and hydraulics.
With the completion of the five functional tests, the final three tests were considered “operational” in nature, since all were geared towards an all-up countdown, fueling and test-firing of the four RS-25 engines for up to 8.5 minutes, mimicking a full mission duration as closely as practicable on the ground. However, the weather was not quite done with the Green Run, as even the countdown test was delayed a few days in response to the threat of Hurricane Sally.
It was finally completed in early October, although the campaign to fully fuel the Core Stage with 733,000 gallons (3.3 million liters) of liquid oxygen and liquid hydrogen experienced difficulties and a new target date for the Hot Fire Test—previously slated to occur in the week prior to Christmas—has yet to be announced.
“For each of these tests, it is the first time they are conducting the test on a brand-new stage,” NASA’s Tracy McMahan previously told AmericaSpace. “So they don’t really have a hard-stop date. It all depends on what they find during the test, if they have to fix anything or make any adjustments.”
As the Core Stage approaches the end of the Green Run, the other major propulsive element for the SLS are the twin SRBs, which, when their segments are fully stacked, will each stand some 177 feet (53.9 meters) tall. All ten segments were delivered by prime contractor Northrop Grumman Corp. from the test site in Utah to KSC in Florida back in June and will be stacked and integrated to the Core Stage at some point early next year. Northrop Grumman has also received additional contracts to develop more SRB components for future SLS missions.
Other Artemis-1 hardware in the form of the Launch Vehicle Stage Adapter (LVSA) has shipped to Florida, the Orion spacecraft completed structural testing and the Exploration Upper Stage (EUS)—a propulsive element for deep-space expeditions beyond Artemis-4—wrapped up its Critical Design Review (PDR) just before Christmas.
Current plans anticipate the maiden flight of the SLS and the Artemis-1 mission at some point late in 2021, with the crewed Artemis-2 expected to conduct a circumlunar voyage in the summer of 2023, followed by the Artemis-3 the following year, which is expected to see the return of humans to the surface of the Moon for the first time since Apollo 17.
Earlier this month, a cadre of 18 astronauts—nine men and nine women—were announced with great fanfare by Vice President Mike Pence and NASA Administrator Jim Bridenstine as the first cadre of the so-called “Artemis Team”.
As if to underline the urgency with which Artemis is hitting the ground running, and perhaps to better safeguard its political future as a new administration enters the White House on 20 January, NASA in April selected SpaceX, Dynetics and the Blue Origin National Team to develop concepts and training hardware for a Human Landing System (HLS) to achieve boots on the Moon by 2024.
The Blue Origin National Team delivered training hardware for its HLS design to the Space Vehicle Mockup Facility (SVMF) at the Johnson Space Center (JSC) in Houston, Texas, in August, and a formal “down-select” from three to two providers is anticipated early in the New Year. And with Canada having recently committed to building the Canadarm3 robotic asset for the lunar-circling Gateway, a place for one of its astronauts has been confirmed on the Artemis-2 mission.
Interestingly, two of the astronauts selected for the Artemis Team—Kate Rubins and Victor Glover—are currently serving aboard the International Space Station (ISS) as members of Expedition 64. They form part of the station’s first long-duration crew of seven, which has been enabled following the arrival of Dragon Resilience on 16 November.
Indeed, 2020 has been a triumphant year for the sprawling multi-national outpost. Back in January, the six-person Expedition 61 crew, commanded by Italian astronaut Luca Parmitano, was aboard the station and had achieved a raft of impressive accomplishments, including the first all-female Extravehicular Activity (EVA), the repair of the Alpha Magnetic Spectrometer (AMS)-2 and the longest single space voyage ever undertaken by a woman.
With the return to Earth of Parmitano, Russian cosmonaut Aleksandr Skvortsov and long-duration record-breaker Christina Koch in February, their crewmates Oleg Skripochka, Drew Morgan and Jessica Meir remained aboard as Expedition 62 until mid-April.
On 9 April, Soyuz MS-16 launched from the Baikonur Cosmodrome in Kazakhstan, carrying Russian cosmonauts Anatoli Ivanishin and Ivan Vagner, together with former chief astronaut Chris Cassidy, to kick off Expedition 63. Seven weeks later, on 30 May, the first mission of Crew Dragon with astronauts aboard—Demo-2, with seasoned shuttle veterans Doug Hurley and Bob Behnken—launched atop a Falcon 9 from historic Pad 39A at KSC.
In doing so, the United States restored its capability to launch its own astronauts, aboard its own spacecraft, atop its own rockets, and from its native soil, and ended a near-nine-year hiatus since the July 2011 retirement of the Space Shuttle. Less than a day after launch, Hurley and Behnken docked the ship they had named “Dragon Endeavour” onto the ISS and Expedition 63 expanded into a five-man crew for the next couple of months.
In addition to the benefits of having the additional crew members aboard in terms of bolstering science and the capacity to handle ISS maintenance, the presence of a three-strong complement in the U.S. Operational Segment (USOS) also permitted the completion of four EVAs to replace aging nickel-hydrogen batteries in the S-6 truss with smaller and more powerful lithium-ion units.
Between 26 June and 21 July, Cassidy and Behnken—both of whom had logged six EVAs apiece, earlier in their careers—ventured outside the station on no fewer than four occasions and a total of 23.5 spacewalking hours to complete the work.
With the completion of this quartet of spacewalks, Cassidy and Behnken joined a pretty exclusive club of only four Americans to have notched up as many as ten EVAs across their careers. Hurley and Behnken returned smoothly to Earth aboard Dragon Endeavour on 2 August, performing a parachute-assisted splashdown in the Gulf of Mexico after 64 days in space and 1,024 orbits.
In the meantime, Cassidy, Ivanishin and Vagner remained aboard the ISS as a three-man crew until Soyuz MS-17 rose from Baikonur on 14 October, carrying their replacements: Russian cosmonauts Sergei Ryzhikov and Sergei Kud-Sverchkov and NASA’s Kate Rubins. (The latter actually launched on her birthday, becoming only the fifth person and the first woman in history to do so.)
A month later, Crew-1 launched from KSC with NASA astronauts Mike Hopkins, Victor Glover and Shannon Walker, together Japan’s Soichi Noguchi. Upon their arrival aboard Dragon Resilience at the station, the new Expedition 64 expanded to seven members. Although larger crews have been seen in past years, they have only occurred for a matter of days; Expedition 64 is expected to mark the start of permanent seven-crew operations, with “direct handovers” effected by Commercial Crew or Soyuz.