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CAPSTONE satellite

"It's a learning journey for humanity" — NASA space scientist Jack Lissauer

October 19, 2022 | 8 min read

By Ian Evans

A NASA scientist talks about the James Webb Space Telescope, the CAPSTONE mission, and the importance of space research

When Dr Jack Lissauer(opens in new tab/window), Space Scientist at NASA’s Ames Research Center(opens in new tab/window) in Silicon Valley, talks about space science, he likes to focus on the connection with the public. As the James Webb Space Telescope(opens in new tab/window) sends extraordinary images back to NASA, and smaller but still important projects like CAPSTONE(opens in new tab/window) test new technologies and concepts, Jack reflected on the importance of space with regard to science communication.

“With projects like James Webb, you’re going to get a lot of people interested in science,” said Jack, who is Editor of Planetary Physics for Elsevier's journal New Astronomy Reviews(opens in new tab/window).

"As with the Hubble Telescope and the Kepler mission, it's the kind of thing that many children are really excited by, and which gets them to dive into their math and science classes. Some of them become scientists, and many more of the become engineers or some other related profession.

There are so may advantages to bringing space science to the attention of the public."


Jack Lissauer

Space Scientist, Professor & Editor at Planetary Systems Branch of NASA's Ames Research Center, Stanford University, Elsevier's journal New Astronomy Reviews

Speaking just after the first images were relayed from the James Webb telescope, Jack noted the buzz around NASA:

There’ve been a few talks held in the Space Science and Astrobiology Division at NASA Ames about what we’re seeing, and people are excited and discussing the images. But right now, the amount of data that has been received is very small, so while the public is obviously energized by these gorgeous images, the more significant thing for the science community will be the data to be obtained in the upcoming months and years.

Although James Webb had seized the headlines, Jack spoke to Elsevier Connect to discuss a different NASA mission: CAPSTONE (the Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment.) This mission kicked off in June with the launch of a satellite the size of a microwave oven weighing just 55 pounds. The mission was intended to test various technologies and concepts, including a new orbit that will reduce the amount of energy required to get the moon, and may lay the foundations for the viability of a lunar space station. Jack elaborated:

I think that the orbit is the thing that’s had the most attention, and it’s a really interesting element of the mission because it’s not intuitive at all.

CAPSTONE’s elliptical orbit will send the spacecraft within 1,000 miles of one lunar pole on its near pass, but out to 43,500 miles from the other pole at its peak. This experimental orbit actually uses less fuel than circular orbits. Jack continued:

As it uses less fuel, you can get more mass up there. If you wanted to support a lunar base with the least amount of energy expenditure, you’ll need some elements on the moon, and some elements in orbit around the moon. One of the things CAPSTONE tests is an inexpensive, low-energy way of achieving that.

The long, elliptical orbit being less energy-intensive is counter-intuitive, Jack said, and it draws on one of his specialist areas — planetary dynamics:

Say for example that you wanted to send a spacecraft really close to the sun. What’s the lowest energy way to do that? It’s not to launch it towards the sun, it’s to send the spacecraft out to Jupiter and then and let Jupiter take its angular momentum away and then slingshot it to the sun. Using that method, you can cut down the energy needed substantially. What CAPSTONE is doing is using a similar idea with these very elongated trajectories

At the time of our interview, CAPSTONE was on track to meet its trajectory. However, shortly afterwards, the spacecraft experienced communications issues while in contact with NASA’s Deep Space Network. Following the declaration of an operational emergency, NASA’s team was able to determine that the unit was operating in safe mode and took steps to reconfigure the probe. The unwanted spinning is now under control, and CAPSTONE remains on track to insert into its targeted Near Rectilinear Halo Orbit at the moon on November 13.

Image of CAPSTONE satellite over the lunar North Pole

The CAPSTONE satellite over the lunar North Pole. (Illustration by NASA/Daniel Rutter)

CAPSTONE will then spend at least six months orbiting the moon to help researchers understand the characteristics of the orbit. It will validate the power and propulsion requirements for the orbit, reducing logistical uncertainties. It will also test the reliability of new spacecraft-to-spacecraft navigation solutions, as well as communication capabilities with Earth.

Listening to Jack discuss these innovations, alongside planetary dynamics, it’s clear that one of the reasons he believes in the power of space science to inspire others is because he himself is so passionate about it:

I think one of the most satisfying aspects is discovering new things. Some of that is mathematical — I worked on the origin of planetary rotation(opens in new tab/window) and provided some of the analytical solutions. But some of it is data.

Jack described the joy of interpreting data, how information relayed from a telescope in space can reveal new planets, and information about those planets:

Jack described the joy of interpreting data, how information relayed from a telescope in space can reveal new planets, and information about those planets

As Jack noted, space-based research is one of the areas where science crosses over into the public imagination, and as such it represents an opportunity to build public understanding of science in general. He explained:

I think it’s important for people to understand that we researchers are still learning. CAPSTONE is about us learning. James Webb is about us learning. I don’t think that’s something that’s always understood by the public, and it leads to controversies. As we saw in the pandemic, when recommendations were changed because people were still learning about the virus, it opened the door to controversies and politicians using it as a wedge issue. Part of that is because the public doesn’t fully understand how science is done.

Space science, then, provides a chance to emphasize research as a process of building an understanding and testing theories. That approach is thoroughly embedded in CAPSTONE, where in addition to communication technology and innovative orbits, NASA partners will test cutting-edge tools for mission planning and operations, paving the way and expanding opportunities for small and more affordable space and exploration missions to the moon, Mars and other destinations throughout the solar system.

“As I say, there’s a lot of satisfaction in discovering new things, and missions like CAPSTONE are packed with various technologies and models we’re testing,” Jack says:

There are a lot of advantages, and it’s really a learning journey. It’s a learning journey for humanity.


Portrait photo of Ian Evans


Ian Evans

Senior Director, Editorial, Content & Brand


Read more about Ian Evans