Catégorie : Media

Artemis I Launches U.S.’s Long-Awaited Return to the Moon

The first flight test of the world’s most powerful rocket will send an uncrewed spacecraft to lunar orbit and back. Article in Scientific American on 16/11/2022 by Nadia Drake

KENNEDY SPACE CENTER, Florida—Taller than the Statue of Liberty, the ochre rocket thundered into the sky around 1:47 A.M. ET, cleaving the darkness with a searing column of crackling fire and sending shudders through the ground near Cape Canaveral, Fla. Bound for the moon, it carried an uncrewed space capsule and a bounty of scientific payloads. But its most profound cargo is a psychic slice of the “American Dream”—a promise that, at least in spaceflight, the U.S. remains exceptional, with capabilities, ambitions and achievements as yet unsurpassed.

Tonight’s launch should have been a triumph. And in many ways, it was. But it also marked the culmination of a long, difficult and frustrating campaign to get a beleaguered rocket off the ground.

Still, thousands of visitors jammed the roads near Kennedy Space Center, many vying for coveted shoreline spots to witness what can still be rightfully called one of the biggest spectacles in recent history: The launch of NASA’s Artemis I mission—the first flight of the agency’s massive new Space Launch System (SLS) rocket and Orion spacecraft. For some of the spectators, it was their third trip to see this rocket launch from Florida’s “Space Coast,” the storied epicenter of U.S. spaceflight where Apollo astronauts last launched to the moon a half-century ago. And then there were the NASA leaders, the blue flight suit-clad representatives of the agency’s astronaut corps, and hundreds of caffeinated space reporters.

“Well, for once I might be speechless,” launch director Charlie Blackwell-Thompson told her team after the launch. “What you have done today will inspire generations to come.”

Nearly three months have gone by since NASA’s first two launch attempts, both of which scrubbed because of difficulty filling the mammoth SLS fuel tanks. Hurricane Ian foiled a planned third attempt when dangerous forecasts sent the rocket back to the safety of the Vehicle Assembly Building (VAB) in late September. And when NASA finally rolled the stack back to the pad in early November, Hurricane Nicole blew through—before the agency could return the rocket to shelter in the VAB.

“I think it’s safe to say for all of us, we obviously would not have wanted to stay out there,” NASA’s Jim Free, associate administrator for exploration systems development, told reporters on Nov. 11. “The best place for the vehicle in those kinds of things is the VAB. We could not make it back to the VAB and be safe. So we stayed where we were.”

The storm hammered the SLS with winds blowing at up to 100 miles per hour, tearing off sealants and presenting mission managers with an almost unthinkably bad predicament: Is it safe to launch a $4.1-billion rocket and spacecraft that have just weathered a category 1 storm?

Ultimately, officials decided to roll the dice and go ahead with the launch. Now, if the entire Artemis I mission is successful, it will mark the first tentative step toward returning humans to the lunar surface.

“This is a big moment of truth for NASA, similar to a ‘return to flight’ situation following a disaster,” says space historian Jordan Bimm of the University of Chicago. “Does NASA still have what it takes when it comes to human spaceflight? It’s been 11 years since NASA last launched a human-rated spacecraft, and this is an entirely new system, long in development.”

NASA officials have said that several off-ramps exist, should Orion encounter challenges that threaten its survival. But if, after its 25.5-day journey, the capsule safely splashes down in the Pacific Ocean, the stage is set for Artemis II, which could carry a four-person crew into lunar orbit as early as 2024. From there, as the Artemis program unfolds, the SLS and Orion could put the first woman and person of color on the moon’s surface, construct a space station in lunar orbit, establish a crewed lunar outpost, and possibly send humans far beyond Earth’s cratered celestial companion—perhaps even to Mars.

But the rationale behind the program, which is estimated to eat more than $90 billion of taxpayer money by the end of 2025, is hazy at best. Why, experts wonder, are we returning humans to the lunar surface? Is it for the sake of science? Is it for the sake of national pride? Or to satisfy an innate human longing for new horizons? And how many times are we willing to go through the trouble of getting these missions off the ground?

“Pursuing the principles of ‘science’ and ‘exploration’ is wonderful and noble,” Bimm says. But he adds, the Artemis program as envisioned “reminds me of [British explorer George] Mallory saying he climbed [Mount] Everest ‘because it’s there.’ Which was a b.s. nonanswer.”

According to Lori Garver, NASA’s former deputy administrator and a well-known critic of the Artemis hardware, the program’s pragmatic purpose is to secure the U.S.’s preeminence in spaceflight—although some of that seems to have been lost in the clamber to the moon. “To me, the goals are not destinations. The goals are what, as a nation, you want to achieve,” she says. “I think the U.S. has got a great leadership position in space, but we should be focusing on keeping that lead, widening that lead, instead of repeating stuff from the past.”

Orion in the Spotlight

Even before the first two scrubs, and the unfortunately timed hurricanes, the stakes were already sky-high for today’s launch, with more than $23 billion of SLS development costs to date along for the ride. Any rocket is inherently a delicately controlled bomb—with all of the accompanying risks—but of course, the SLS isn’t just any rocket. It is a heavy-lift system that, in future iterations, could haul in excess of 100,000 pounds of crew and cargo to the moon and beyond. And in its present form, it already produces 8.8 million pounds of thrust—more than that of the iconic Apollo-era Saturn V—as it slips Earth’s gravitational grip. And perched on top of that beast is a multibillion-dollar spacecraft: Orion.

Ordinarily, the Orion capsule would be protected from any launch mishaps by an abort system tucked inside the pointy cap at the rocket’s apex—a set of three motors delivered by Northrop Grumman that can hurl the capsule away from a malfunctioning booster and do so with gusto: the main abort motor can propel Orion from zero to 400 miles an hour in just two seconds.

“The launch abort system is designed to pull the crew capsule away in case there is an emergency on either the launch pad or during the ascent phase,” said Debbie Korth, Orion’s deputy program manager, to reporters during a briefing before the first launch attempt. “We’re talking very quick, really trying to outrun an SLS that might be having an issue during launch.”

Doug Hurley, a former NASA astronaut and military pilot who flew space shuttle missions and commanded the first crewed mission of SpaceX’s Dragon capsule in 2020, told Scientific American that having an abort system is a relief for everyone aboard a rocket—and for their families back on the ground.

“Getting on a rocket knowing that if the day turns horribly bad you still have a great chance of getting back to your family—it’s amazing. It’s something we didn’t have in shuttle,” says Hurley, now Northrop Grumman’s senior director of business development. “It’s an incredibly great piece of mind to have.”

Because no humans are onboard for the Artemis I mission, Orion’s main abort motor is inactive. Thankfully, the SLS has so far done its job. After liftoff, the rocket survived its period of maximum dynamic pressure in the atmosphere, throttled up its main engines and delivered Orion to Earth orbit. Then the rocket’s core stage detached and began an ignominious descent to the bottom of the Pacific Ocean, leaving the crew capsule and the upper stage, called the interim cryogenic propulsion system (ICPS), to continue their journey.

The mission’s next big challenge began about an hour and a half after launch. To reach the moon, the ICPS needed to precisely execute a long engine burn called translunar injection, or TLI. For 18 minutes, it fired its engines, accelerating the Orion spacecraft from 17,500 miles an hour to 22,000 miles an hour—the speed required to shrug off Earth’s gravity and instead cling to the moon.

If the burn had gone awry, Orion could have missed the moon entirely. On this test flight, NASA officials were so keen to perform the crucial TLI that they were determined to go for it unless the maneuver was guaranteed to result in a loss of the spacecraft. “We would be ‘go’ on this flight for conditions that we would normally be ‘no-go’ for on a crewed flight, in the interest of crew safety,” said Mike Sarafin, Artemis I’s mission manager at NASA, during a late summer prelaunch briefing. “That is something that is unique to this uncrewed flight test, and we are going to press ahead and press uphill unless we’re almost for sure we’re going to lose” the vehicle.

Post-TLI, Orion detached from the ICPS and sailed on to the moon in solitude. For the rest of its mission, the spacecraft will be flying under its own power using onboard navigation and propulsion systems.

“There are certain cases that could come up that could cause us to come home early,” said NASA’s associate administrator Bob Cabana to reporters before the first launch attempt. “And that’s okay. We have contingencies in place.” But, he added, “the main objective that we really want to get out of this test flight, of course, is stressing that heat shield—getting a test of that new Orion heat shield at lunar reentry velocities.”

If Orion returns safely to Earth, it will create new possibilities for humankind’s off-world future—ones that necessarily involve the bulky, expensive Artemis hardware. “SLS and Orion working perfectly on the test flight will make it unstoppable for the next flight,” Garver says. “We absolutely march forward.”

Lessons from a Lunar Return

The next flight, Artemis II, would be similar in profile to 1968’s Apollo 8 mission, which carried three astronauts into lunar orbit and back. Scheduled for 2024, Artemis II would then be followed by an even more complex and historic mission, Artemis III, which would at last return humans to the lunar surface for the first time since 1972.

But why NASA is following this ambitious schedule to press more boot prints into moondust is murky. “Unlike the Apollo missions, which had a clear and urgent political goal of demonstrating American technological mastery during the cold war, the driving motive behind Artemis is far less clear,” Bimm says. “The ‘why’ part has not been clearly formulated or articulated, and the lack of real urgency could see the entire Artemis program cut, handed over to private companies or transformed in some other way—even if everything goes smoothly.”

Teasel Muir-Harmony, a space historian at the National Air and Space Museum and curator of its Apollo collection, adds that, in addition to technical prowess, the Apollo missions were meant to influence the political trajectory of independent nations during the cold war. Here, she says, “the idea for Artemis is not to change how the world thinks about the U.S. or to align with the U.S. We’re not doing this to win hearts and minds in the way we once were.”

Even a burgeoning space race with China seems like a convenient excuse, at least as far as the lunar surface goes. “We’ve been to the moon; we’ve won that race,” Garver says. The very first Artemis astronaut to make lunar landfall, she notes, would merely be the 13th human to walk on the moon’s surface.

David Parker, director of human and robotic space exploration for the European Space Agency, argues that visions of a thriving lunar outpost are a natural outgrowth of humankind’s tendency to push the boundaries of where we can live and work. On this planet, he says, we’ve seen something very similar with development in the Antarctic.

“Robert Scott and Roald Amundsen raced to the South Pole in 1911, and then nobody bothered going to the Antarctic for another 50 years. Now we’ve got research stations there, doing every kind of research you can think of,” he told Scientific American. “It’s about expanding the places that human beings live and work.”

Yet even without a strong sense of purpose, the SLS and Orion have broad, bipartisan political support. And the Artemis program, established in 2017, long after both the SLS and Orion had begun development, successfully endured the transition between presidential administrations—a perilous time when problematic federal projects are traditionally culled. Its survival, Muir-Harmony says, bodes well for its longevity, even though it has become something of a boondoggle for the space agency.

Perhaps there are lessons to learn from the response to other late and over-budget projects in NASA’s portfolio—such as the James Webb Space Telescope, or JWST.

“When you look back at the experience with Apollo, the experience even with JWST in the past few months and how that has brought together humanity around the globe with the excitement of learning new things…I don’t know how you don’t get excited about Artemis, to be honest with you,” says Daniel Dumbacher, who oversaw the SLS’s initial development while he was at NASA and now serves as executive director of the American Institute of Aeronautics and Astronautics.

As with the SLS and Orion, contractors delivered JWST years late and billions of dollars over budget. It also needed to survive a risky deployment phase in which any of 344 single points of failure could have spelled disaster for the mission. But in the end, it worked. Now, as JWST’s sharp infrared eye reveals the cosmos in a new light, no one is complaining about its oversize price tag. Instead astronomers are dreaming up new questions they’d never thought to ask.

“Maybe the Artemis missions will do the same with human exploration—help us build that new capability, sustainable on the moon, and then expand out to Mars,” Dumbacher muses. “It’s going to open up new economic opportunities for generations to come.”

Maybe that will be the case—and maybe not. JWST had an express purpose—to peer as far back in time as possible, to see the universe as it was when the first stars and galaxies began emerging from the primordial gloom and to connect the dots between those infant structures and the living world we know. And there was only one way to do that: build a giant telescope, an instrument so big it would have to tuck itself into a rocket fairing and unfold in space.

The SLS and Orion don’t check those same boxes. Although researchers have no shortage of ideas for leveraging Artemis’s rockets to accomplish transformative science, the lunar-return program lacks clear motivations, aside from political posturing and providing a concrete destination for its hardware to reach—hardware that was arguably designed foremost not for voyaging to the moon or Mars but for maintaining the momentum built up across the past half-century of sometimes fickle federal investment in civil spaceflight. In many respects, although the SLS and Orion are meant to lead the way to NASA’s bright future, they instead risk relegating the space agency to the past. There are, after all, other ways to put humans in deep space that are much cheaper and possibly more efficient. Yet if Artemis succeeds and returns humans to the lunar surface, perhaps the program’s critics will be as silent as those who’d rallied for the cancellation of JWST.

“From my perspective, we owe it to the next generation—and the generations that follow—to continue pushing forward and pushing outward and to continue learning,” Dumbacher says.

ABOUT THE AUTHOR

Nadia Drake is a science journalist who specializes in covering astronomy, astrophysics and planetary science. Her byline has appeared in National Geographic, the New York Times and the Atlantic, among other publications.