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NASA’s Artemis I revives the Moonshot

“When you look at the rocket, it looks almost retro,” he said. bill nelson, the administrator of NASA. “It looks like we’re looking at the Saturn V. But it’s a totally different, new, highly sophisticated, more sophisticated rocket and spacecraft.”

sagebrushpowered by the Space Launch System rocket, it is the first attempt by the United States to send astronauts to the moon since apollo 17 in 1972, and the technology has come a long way since then. In Artemis Ithe first test flight, mission managers say they are taking the SLS, with its unmanned crew Orion spacecraft on top, and “stress it beyond what it’s designed for,” the best to ensure safe flights when astronauts make their first landings, currently a goal to begin with Artemis III in 2025.

But Nelson is right: the rocket it is retro in many ways, borrowing heavily from the space shuttles America flew for 30 years, and from the Apollo-Saturn V.

Much of Artemis’s hardware is refurbished: its four main engines and parts of its two belt drives, all of which have flown shuttle missions before. The rocket’s apricot color comes from spray-on insulation, much like the foam in the shuttle’s external tank. And the big maneuvering engine in the Orion service module is actually 40 years old and was used on 19 space shuttle flights between 1984 and 1992.

“I have a name for missions that use too much new technology: glitches.”
—John Casani, NASA

Perhaps most importantly, the project inherits basic engineering from half a century of spaceflight. Just look at the Orion crew capsule: a truncated cone, somewhat larger than the Apollo command module but conceptually very similar.

Old, of course, does not mean bad. NASA says there’s no need to reinvent things that engineers got right the first time.

“There are certain fundamental aspects of deep space exploration that are really independent of money,” he says. Jim Gefre, Orion Vehicle Integration Manager at the Johnson Space Center in Houston. “The laws of physics haven’t changed since the 1960s. And it turns out the capsule shapes are really good at getting back into the atmosphere at Mach 32.”

Roger Launiowho served as NASA’s chief historian from 1990 to 2002 and as a curator at the Smithsonian Institution from then until 2017, recounts a conversation he had with John Casania veteran NASA engineer who directed the Voyager, Galileo, and Cassini spacecraft to the outer planets.

“I have a name for missions that use too much new technology,” Casani recalls saying. “Failures”.

The Artemis I flight is scheduled for about six weeks. (apollo 11 it lasted eight days.) The spacecraft roughly follows Apollo’s path to the moon’s neighborhood, but then settles into what NASA calls a distant retrograde orbit. It dives within 110km of the lunar surface to get help from gravity, then zooms out 64,000km, which takes more than a month but uses less fuel than closer orbits. Finally, it returns home, re-enters the Earth’s atmosphere at 11 km per second, slows down with a heat shield and parachute, and falls into the Pacific not far from San Diego.

If all four quadruple-redundant flight computer modules fail, there’s an entirely separate fifth computer on board, running different code to bring the spacecraft home.

“That extra time in space,” Geffre says, “allows us to operate the systems, give more time in deep space and all those things that stress it out, like radiation and micrometeoroids, thermal environments.”

There are, of course, new technologies on board. Orion is controlled by two vehicle management computers, each made up of two flight computer modules (FCMs) to handle guidance, navigation, propulsion, communications and other systems. The flight control system, Geffre points out, is quadruple redundant; if at any time one of the four FCMs disagrees with the others, it will go offline and, in a 22-second process, restart itself to ensure its results are consistent with the others. If all four FCMs fail, there’s an entirely separate fifth computer running different code to get the spacecraft home.

Orientation and navigation have also advanced since the sextant used on Apollo. Orion uses a star tracker to determine its attitude, taking pictures of the stars and comparing them to an onboard database. And an optical navigation camera takes images of the Earth and Moon so guidance software can determine their distance and position and keep the spacecraft on course. NASA says it’s there as a backup, capable of getting Orion to a safe splashdown even if all communication with Earth has been lost.

But even those systems are not entirely new. Geffre notes that the architecture of the guidance system is derived from the Boeing 787. Computing power in deep space is limited by cosmic radiation, which can corrupt the output of microprocessors beyond the protection of Earth’s atmosphere and magnetic field. the earth.

Beyond that is the inevitable question of cost. Artemis is a giant, years-overdue project that began long before NASA began buying other launches from companies like SpaceX and Rocket Lab. NASA Inspector General Paul Martin certified before congressin March that the first four Artemis missions would cost $4.1 billion each, “a price that seems unsustainable to us.”

Launius, for his part, rejects the argument that government is inherently wasteful. “Yes, NASA has had problems managing programs in the past. Who hasn’t?” Hey, he says. He points out that Blue Origin and SpaceX have had plenty of mishaps of their own, they just aren’t required to go public. “I could go on and on. It’s not a government thing per se and it’s not a government thing. of NASA per se”.

So why go back to the moon with, pardon the pun, such a retro rocket? In part, say those who closely watch Artemis, because it has become too big to fail, with so much American money and brainpower invested in it. Partly because it gets NASA astronauts back out there, exploring rather than maintaining a space station. Partly because new perspectives could emerge. and partly because China and Russia they have ambitions in space that threaten those of the United States.

“Apollo was a technological verisimilitude demonstration for the whole world,” says Launius. “And the whole world knew then, as they know today, that the future belongs to the civilization that can master science and technology.”

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