NASA’s long-awaited return to the Moon is set to draw closer with tonight’s launch of the largest and most powerful rocket ever built.
The rocket is scheduled to lift off from Kennedy Space Center at 10:30 p.m. (AEST) from the same pad used by the last Apollo mission 50 years ago.
Perched atop the 32-story rocket is a new space capsule meant to fly past the Moon and back.
“We’re going to launch the world’s only spacecraft designed to carry humans into deep space, atop the most powerful rocket,” NASA chief Bill Nelson said.
Controlled by a crash-test dummy called Commander Moonikin Camposthe uncrewed flight is the inaugural test of the Artemis program, NASA’s push to put humans back on the Moon and eventually get to Mars.
“With the launch of Artemis 1, NASA…is about to begin the most significant series of human exploration missions in more than a generation,” said Bhavya Lal, NASA Associate Administrator for Technology, policy and strategy.
The 42 day trip will not only push the all-new rocket and capsule to the limit, it will test a new orbit and go further than a craft capable of taking a crew further beyond the Moon has ever been able to before.
It also goes launch 10 shoebox-sized satellites to locate the Moon and explore conditions for future deep space missions.
A big test for a new spacecraft
Even though the rocket and capsule may look a little retro, the mission is very different from the Apollo missions which operated on less computing power than your cell phone today.
Let’s start with the rocket.
At over 98 meters high, NASA’s Space Launch System (SLS) rocket has more power than the Saturn V used to launch Apollo.
Its four engines, which are redesigns of the design developed for the Space Shuttle program, can put 27 metric tons into orbit beyond the Moon in one go.
As it explodes into space, it will travel to 32 times the speed of sound.
It will also be the first release of the Orion spacecraft.
The spaceship is made up of three parts.
- The crew sectionwhich can accommodate four astronauts in specialized seats for up to 21 days without mooring
- The service modulesbuilt by the European Space Agency (ESA), which contains solar panels and power modules, as well as all capsule components life support systems
- The conical shape start the abandon systemwhich sits on top of the capsule and is designed to be jettisoned in an emergency right after takeoff
The big test will be how the rocket and capsule fit together and communicate with the ground station, said Aude Vignelles, chief technology officer at the Australian Space Agency, which is a signatory to the Artemis program but is not involved in the launch.
“Integration is key, as each element is developed and manufactured by different entities,” she said.
“So when you put everything together, you’re testing whether your interface has been well defined and whether the individual tests have been well done.
“It’s really the last tick before sending humans on top of this rocket in this capsule.”
So what are the big challenges?
Artemis 1 is a “very risky” mission, said NASA’s Jim Free.
“We have simple but aggressive goals – which is to get the vehicle into orbit, into orbit and back home.
“We have a lot of things that could go wrong in the mission, where we may have to abort early to get home.”
Surviving takeoff is the first challenge the mission is facing, and the first two minutes are critical.
As the rocket vibrates through the air, burning 1,360 tons of liquid hydrogen and oxygen, it reach its greatest pressure point known as max q.
Within eight minutes, when the rocket is about to 160 kilometers above Earth, it will drop its empty fuel tanks and core.
The top half of the rocket and capsule then take about two hours for a land touras the capsules’ solar panels unfold.
The rocket and Orion separate, releasing 10 shoebox satellites, then the capsule’s engines fire and propel it to the Moon.
Flying less than 106 kilometers from the lunar surface, it will then use the Moon’s gravity to launch it into a deep space orbit.
This orbit, called the far retrograde orbit, will take Orion 64,000 kilometers beyond the far side of the Moon.
This will test Orion’s navigation, propulsion and communications systems in deep space.
Although this is a very stable orbit, it is well beyond the range of communications systems used for low earth operations such as the International Space Station.
NASA will communicate with the capsule using its Deep Space Network radio antennas in California, and near Canberra and Madrid.
After spending between one and two weeks in this orbit, Orion will begin its journey back to Earth.
As it makes another close flight behind the Moon, it will re-ignite its engines and use the Moon’s gravity to send it back to Earth.
A mistake at this point means it could overshoot and return to deep space.
Then it faces its most important test: reentering the Earth’s atmosphere.
Back-to-school challenges
The 4.8 meter diameter heat shield is critical to spacecraft survival during the return.
As it hurtles towards Earth at 44,000 kilometers per hour, Orion will become a bubble surrounded by hot plasma reaching temperatures of up to 2,765 degrees Celsius, half the heat of the Sun’s surface.
Instead of plunging into the atmosphere, like Apollo, Artemis 1 divide the start of the school year into two phasesplunging in and out of Earth’s atmosphere like a stone skipping across a pond.
If it does not burn up in the first phase, it will deploy parachutes and crash in the Pacific off California on October 10.
Then it will be recovered so that scientists can analyze the data and reuse parts of the capsule for future flights.
Intense sound. How many will we see?
You can watch the launch and follow the spacecraft through its 42-day journey on NASA’s website and its social media pages.
A breathtaking view of the Earth extracted from the capsule during its propulsion in space will be released within hours of launch.
And the images of the far side of the Moon will rival the famous Earthrise photos taken by Apollo 8 astronauts in 1968, mission chief Mike Sarafin said.
“Orion will take selfies on its solar wings of itself in the foreground, the Moon in the background, and the Earth [460,000km] a way.”
There are also 360 degree cameras inside the capsule.
What happens inside the capsule?
Moonikin Campos, the crash test dummy (named after the engineer who saved Apollo 13) won’t be alone.
One of the experiments on board, Callisto, is testing a virtual assistant to respond to voice commands like the spaceship in Star Trek, Dr Lal said.
The system will use a version of Alexa from Amazon.
It will start with turning the lights on and off, but “it could lead to technology that will turn science fiction into reality on future crewed missions,” she said.
Moonikin Campos will be test NASA spacesuit for radiation and is hooked up to sensors to see how the human body reacts to vibrations in the commander’s seat.
Helga and Zohra, ghost torsos made of materials that mimic the tissues and organs of human women, will test the feeling of driving in the two rear seats.
The phantoms, covered with 5,600 sensors, are also part of an experiment to see how radiation affects the human body, and in particular women.
Without the protection of the Earth’s magnetic field, astronauts traveling to the Moon will be exposed to more intense radiation, for much longer, than a trip to the International Space Station.
Although the science is not established, it is believed that women have more tissue that is sensitive to the effects of radiation. Zohra will therefore be testing a radiation vest to see if it provides additional protection.
How does this mission fit into the long game?
Artemis 1 is the first in a series of missions.
NASA plans to send Artemis 2the first crewed mission to space, in 2024 (although concerns have already been raised about whether the spacesuits will be ready).
This flight will use an even more powerful version of the SLS rocket to lift crew and cargo off the ground.
In 2025, NASA plans to land the first woman and first person of color near the South Pole of the Moon on Artemis 3.
Two of the Artemis 1 mission’s shoebox satellites will map water at the South Pole, and another will test landing technology.
Artemis 4which is scheduled for sometime after 2027, will take astronauts to a mini lunar station called Gateway.
“The goal is not to send people to the moon and stay there, the goal is to transit from the lunar gate and land on the moon and start building whatever you need. to build on the Moon,” said Dr Vignelles.
Some of the onboard experiments and shoebox satellites on Artemis 1 are designed to detect conditions that may affect humans living in deep space, such as radiation, micro meteorites and cosmic rays.
After establishing a lunar base, NASA hopes to send humans to Mars towards the end of the next decade.
It’s a bold plan, but Artemis 1 must first complete its first challenge and take off.
If tonight’s window is missing, the next scheduled dates are September 2 and 5.
