NASA launches Capstone, a 55-pound CubeSat to the moon


NASA will be busy on the moon for years to come.

A giant rocket will lift a capsule around the moon and back with no astronauts on board, perhaps before the end of summer. A parade of robotic landers will drop experiments on the moon to collect vast amounts of scientific data, particularly on water ice trapped in the polar regions. Astronauts are expected to return there in a few years, more than half a century since the last Apollo moon landing.

These are all part of NASA’s 21st Century Lunar Program, named after Artemis, who was Apollo’s twin sister in Greek mythology.

A spacecraft called CAPSTONE is scheduled to launch early Monday as the first piece of Artemis to the moon. It’s modest in size and scope compared to what’s to come.

There will be no astronauts on board CAPSTONE. The spaceship is too small, about the size of a microwave oven. This robotic probe won’t even land on the moon.

But it’s unlike any previous mission to the moon in many ways. It could serve as a template for future public-private partnerships that NASA could enter into to get more bang for its buck in interplanetary travel.

“NASA has gone to the moon before, but I’m not sure it was ever put together that way,” said Bradley Cheetham, executive director and president of Advanced Space, the company leading the mission for NASA.

Reporting on the launch will air Monday at 5 p.m. Eastern Time on NASA TV. The rocket must launch at exactly 5:50 a.m. to place the spacecraft on the correct trajectory.

The mission’s full name is Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment. It will act as a scout for lunar orbit where a manned space station will eventually be built as part of Artemis. This outpost, named Gateway, will serve as a way station where future crews will stop before proceeding to the lunar surface.

CAPSTONE is unusual for NASA in several respects. For one, it’s sitting on a launch pad not in Florida but in New Zealand. Second, NASA has not designed, built, and will not operate CAPSTONE. The agency doesn’t even own it. CAPSTONE is part of Advanced Space, a company with 45 employees on the outskirts of Denver.

The spacecraft will take a slow but efficient trajectory to the Moon, arriving on November 13th. If weather or a technical problem causes the rocket to miss that immediate launch time, there are additional chances until July 27. By then, it will enter lunar orbit the same day, November 13.

The CAPSTONE mission continues NASA’s efforts to work in new ways with private companies in hopes of gaining additional capabilities more quickly at a lower cost.

“It’s another way for NASA to figure out what it needs to figure out and cut costs,” said NASA Administrator Bill Nelson.

Advance Space’s 2019 contract with NASA for CAPSTONE cost $20 million. The trip to space for CAPSTONE is also small and cheap: just under $10 million for a launch from Rocket Lab, a US-New Zealand company which is a leader in delivering small payloads into orbit.

“In less than three years, it will be less than $30 million,” said Christopher Baker, program manager for small spacecraft technology at NASA. “Relatively quick and relatively inexpensive.”

“I see this as a signpost for how we can help facilitate commercial missions beyond Earth,” said Mr. Baker.

CAPSTONE’s main objective is to last six months, with the possibility of an additional year, said Dr. Cheetham.

The data collected will aid the planners of the lunar outpost known as the Gateway.

When President Donald J. Trump said in 2017 that sending astronauts back to the moon was a top priority of his administration’s space policy, the watchwords at NASA were “reusable” and “sustainable.”

That prompted NASA to make a space station around the moon a key element of how astronauts would get to the lunar surface. Such a location would make it easier for them to reach different parts of the moon.

The first Artemis land mission, currently scheduled for 2025 but likely to be postponed, will not use Gateway. But subsequent missions will.

NASA decided that the best location for this outpost would be in what is known as a near-straight line halo orbit.

Halo orbits are affected by the gravity of two bodies – in this case, the Earth and the Moon. The influence of the two bodies helps make the orbit very stable, minimizing the amount of fuel needed to keep a spacecraft in lunar orbit.

The gravitational interactions also keep the orbit at an angle of about 90 degrees to the line of sight from Earth. (This is the near-straightforward part of the name.) Therefore, a spacecraft in this orbit never passes behind the moon, where communications would be cut off.

The orbit Gateway will fly will approach to within about 2,200 miles of the Moon’s North Pole and end up to 44,000 miles away as it passes over the South Pole. A trip around the moon takes about a week.

In terms of the underlying mathematics, exotic trajectories such as a near rectilinear halo orbit are well understood. But this is also an orbit that no spacecraft has entered before.


“We think we’ve characterized it very, very well,” said Dan Hartman, program manager at Gateway. “But with this special CAPSTONE payload, we can help validate our models.”

In practice, without global positioning system satellites around the moon to pinpoint precise positions, it might take some trial and error to figure out how best to keep the spacecraft in the desired orbit.

“The biggest uncertainty is knowing where you are,” said Dr. Cheetham. “In space, you never know exactly where you are. So you always have an estimate of where it is, with some uncertainty.”

Like other NASA missions, CAPSTONE triangulates an estimate of its position using Signals from NASA’s Deep Space Network from radio antennas and then, if necessary, shifts back into the desired orbit shortly after passing the furthest point from the moon.

CAPSTONE will also test an alternative method of determining its position. It is unlikely that anyone will invest the time and money to build a GPS network around the moon. But there are other spacecraft, including NASA’s Lunar Reconnaissance Orbiterorbiting the moon, and more are likely to be added in the years to come. By communicating with each other, a fleet of spacecraft in different orbits could essentially set up an ad hoc GPS.

Advanced Space has been developing this technology for more than seven years and will now test the concept with CAPSTONE sending signals back and forth with the Lunar Reconnaissance Orbiter. “We will be able to determine where both spacecraft are located over time,” said Dr. Cheetham.

When it began developing CAPSTONE, Advanced Space also decided to add a computer chip-scale atomic clock to the spacecraft and compare that time to the time broadcast by Earth. This data can also help determine the location of the spacecraft.

Because Advanced Space owns CAPSTONE, it had the flexibility to make this change without seeking NASA’s permission. And while the agency still works closely together on projects like this, this flexibility can be a boon for both private companies like Advanced Space and NASA.

“Because we had a commercial contract with our suppliers, if we had to change something, we didn’t have to go through a huge vetting process from government officials,” said Dr. Cheetham. “That helped from a speed perspective.”

The downside is that the company couldn’t go to NASA to ask for additional money because Advanced Space had negotiated a fixed fee for the mission (although it was due to supply chain delays caused by the Covid-19 pandemic , additional payments received). More traditional NASA contracts, known as “Cost-Plus,” reimburse companies for their expenses and then add a fee that’s received as profit, giving them little incentive to keep costs under control.

“When things came up, we had to figure out how to deal with them very efficiently,” said Dr. Cheetham.

This is similar to NASA’s successful strategy of using fixed-price contracts with Elon Musk’s SpaceX, which now carries cargo and astronauts to and from the International Space Station at a much lower cost than the agency’s own space shuttles once did. NASA’s investments allowed SpaceX to attract non-NASA customers interested in launching payloads and private astronauts into orbit.

Until CAPSTONE, Advanced Space’s work was mostly theoretical – analyzing orbits and writing software for its ad hoc GPS – rather than building and operating spacecraft.

The company still isn’t really into spacecraft construction. “We bought the spaceship,” said Dr. Cheetham. “I tell people that the only hardware we build here at Advanced is Lego. We have a great Lego collection.”

In the last few decades tiny satellites known as CubeSats have proliferated, allowing more companies to rapidly build spacecraft based on a standardized design where each cube is 10 centimeters or four inches. CAPSTONE is among the largest at 12 cubes in volume, but Advanced Space was able to buy it almost off the shelf from Tyvak Nano-Satellite Systems of Irvine, California.

That still required a lot of problem solving. For example, most CubeSats are in low Earth orbit just a few hundred miles above the surface. The moon is almost a quarter of a million miles away.

“No one has flown a CubeSat to the moon,” said Dr. Cheetham. “So it makes sense that nobody built radios to fly CubeSats to the moon. And so we had to really dive in to understand a lot of those details and actually work with a few different people to have the systems that could work.”

Mr. Hartman, the Gateway program manager, is excited about CAPSTONE but says it’s not essential to progressing with the lunar outpost. NASA has already awarded contracts to build Gateway’s first two modules. The European Space Agency is also contributing two modules.

“Can we fly without it?” Mr. Hartman said of CAPSTONE. “Yes. Is it mandatory? No.”

But he added, “Anytime you can reduce error bars in your models, it’s always a good thing.”

dr Cheetham is thinking about what could come next, maybe more missions to the moon, either for NASA or other commercial partners. He also thinks ahead.

“I’m very intrigued to think about how we could do something similar to Mars,” he said. “Actually, I am also personally very interested in Venus. I don’t think it gets enough attention.”


Source link

Leave a Reply