posted 11-29-2022 08:13 PM               

NASA's Lunar Flashlight Ready to Search for the Moon's Water Ice

The Moon's poles offer a tantalizing opportunity for human explorers: There may be reservoirs of water ice there that could be purified as drinking water, converted into breathable oxygen, and used as fuel by astronauts. These reservoirs are inside permanently shadowed craters – regions where the Sun never rises above crater rims.

Above: Earlier this year, NASA's Lunar Flashlight mission underwent tests to prepare it for launch in November 2022. The solar-powered small satellite is shown here with its solar arrays extended in a Georgia Tech clean room. (NASA/JPL-Caltech)

It's known that water ice exists below the lunar regolith (broken rock and dust), but scientists don't yet understand whether surface ice frost covers the floors inside these cold craters. To find out, NASA is sending Lunar Flashlight, a small satellite (or SmallSat) no larger than a briefcase. Swooping low over the lunar South Pole, it will use lasers to shed light on these dark craters – much like a prospector looking for hidden treasure by shining a flashlight into a cave. The mission will launch aboard a SpaceX Falcon 9 rocket in November.

"This launch will put the satellite on a trajectory that will take about three months to reach its science orbit," said John Baker, the mission's project manager at NASA's Jet Propulsion Laboratory in Southern California. "Then Lunar Flashlight will try to find water ice on the surface of the Moon in places that nobody else has been able to look."

Fuel-Efficient Orbits

After launch, mission navigators will guide the spacecraft way past the Moon. It will then be slowly pulled back by gravity from Earth and the Sun before it settles into a wide, looping, science-gathering orbit. This near-rectilinear halo orbit will take it 42,000 miles (70,000 kilometers) from the Moon at its most distant point and, at its closest approach, the satellite will graze the surface of the Moon, coming within 9 miles (15 kilometers) above the lunar South Pole.

SmallSats carry a limited amount of propellent, so fuel-intensive orbits aren't possible. A near-rectilinear halo orbit requires far less fuel than traditional orbits, and Lunar Flashlight will be only the second NASA mission to use this type of trajectory. The first is NASA's Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (CAPSTONE) mission, which will arrive at its orbit on Nov. 13, making its closest pass over the Moon's North Pole.

"The reason for this orbit is to be able to come in close enough that Lunar Flashlight can shine its lasers and get a good return from the surface, but to also have a stable orbit that consumes little fuel," said Barbara Cohen, Lunar Flashlight principal investigator at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

As a technology demonstration, Lunar Flashlight will be the first interplanetary spacecraft to use a new kind of "green" propellant that is safer to transport and store than the commonly used in-space propellants such as hydrazine. This new propellant, developed by the Air Force Research Laboratory and tested on a previous NASA technology demonstration mission, burns via a catalyst, rather than requiring a separate oxidizer. That is why it's called a monopropellant. The satellite's propulsion system was developed and built by NASA's Marshall Space Flight Center in Huntsville, Alabama, with integration support from Georgia Tech Research Institute in Atlanta.

Lunar Flashlight will also be the first mission to use a four-laser reflectometer to look for water ice on the Moon. The reflectometer works by using near-infrared wavelengths that are readily absorbed by water to identify ice on the surface. Should the lasers hit bare rock, their light will reflect back to the spacecraft, signaling a lack of ice. But if the light is absorbed, it would mean these dark pockets do indeed contain ice. The greater the absorption, the more ice may be at the surface. 

Lunar Water Cycle

It's thought that molecules of water come from comet and asteroid material impacting the lunar surface, and from solar wind interactions with the lunar regolith. Over time, the molecules may have accumulated as a layer of ice inside "cold traps."

Above: This illustration shows NASA's Lunar Flashlight over the Moon. The SmallSat mission will have a very elongated orbit, taking it within 9 miles (15 kilometers) above the lunar South Pole to search for water ice in the Moon's darkest craters. (NASA)

"We are going to make definitive surface water ice measurements in permanently shadowed regions for the first time," said Cohen. "We will be able to correlate Lunar Flashlight's observations with other lunar missions to understand how extensive that water is and whether it could be used as a resource by future explorers."

Cohen and her science team hope that the data Lunar Flashlight gathers can be used to understand how volatile molecules, like water, cycle from location to location and where they may accumulate, forming a layer of ice in these cold traps.

"This is an exciting time for lunar exploration. The launch of Lunar Flashlight, along with the many small satellite missions aboard Artemis I, may form the foundations for science discoveries as well as support future missions to the Moon's surface," said Roger Hunter, Small Spacecraft Technology program manager at NASA's Ames Research Center in California's Silicon Valley.

More About the Mission

In October, Lunar Flashlight was fueled at NASA's Marshall Space Flight Center in Huntsville, Alabama, and is scheduled to launch aboard a SpaceX Falcon 9 rocket from Cape Canaveral Space Force Station in Florida no earlier than Nov. 30 with the Japanese Hakuto-R lander and United Arab Emirate's Rashid 1 rover. The mission worked with Maverick Space Systems to provide launch integration services.

NASA's Small Business Innovation Research program funded component development from small businesses including Plasma Processes Inc. (Rubicon) for thruster development, Flight Works for pump development, and Beehive Industries (formerly Volunteer Aerospace) for specific 3D printed components. The Air Force Research Laboratory also contributed financially to the development of the Lunar Flashlight propulsion system.

Lunar Flashlight will be operated by Georgia Tech, including graduate and undergraduate students. The mission is funded by the Small Spacecraft Technology program within NASA's Space Technology Mission Directorate.

posted 12-11-2022 08:06 AM               

NASA's Lunar Flashlight Has Launched

Follow the Mission in Real Time

NASA's Lunar Flashlight has communicated with mission controllers and confirmed it is healthy after launching Sunday, Dec. 11, at 2:38 a.m. EST (Saturday, Dec. 10, at 11:38 p.m. PST) from Cape Canaveral Space Force Station in Florida. About 53 minutes after launch, the small satellite, or SmallSat, was released from its dispenser to begin a four-month journey to the Moon to seek out surface water ice in permanently shadowed craters at the lunar South Pole.

"It was a beautiful launch," said John Baker, the Lunar Flashlight project manager at NASA's Jet Propulsion Laboratory in Southern California. "The whole team is excited to see this small spacecraft do some big science in a few months' time."

While Lunar Flashlight will never return to Earth, the world hasn't missed its last chance to see the briefcase-size spacecraft. Rendered in crisp detail, a 3D digital version of the solar-powered SmallSat has made its debut in NASA's Eyes on the Solar System, the agency's recently revamped visualization tool.

"As soon as the Lunar Flashlight mission reached space, Eyes began tracking it, just as it will throughout the SmallSat's entire science mission," said Jason Craig, visualization producer at JPL. "The system uses real trajectory data from the mission, so as Lunar Flashlight's journey unfolds, you can see exactly where the SmallSat is."

The spacecraft's avatar is an exact model of the real thing, down to its four solar arrays, science instrument, and thrusters. With the drag of a finger or mouse, users can change their perspective of the SmallSat and see where it is in space, whether on its long trek to lunar orbit or when it's zooming above the lunar surface, collecting science data.

To get close to the Moon's surface, the SmallSat will employ what's called a near-rectilinear halo orbit – designed for energy efficiency – that will take it within just 9 miles (15 kilometers) over the lunar South Pole and 43,000 miles (70,000 kilometers) away at its farthest point. Only one other spacecraft has employed this type of orbit: NASA's Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (CAPSTONE) mission, which launched earlier this year and can also be viewed in NASA Eyes, including as it makes its closest passes over the lunar North Pole.

Lunar Ice Science

Lunar Flashlight will use a reflectometer equipped with four lasers that emit near-infrared light in wavelengths readily absorbed by surface water ice. This is the first time that multiple colored lasers will be used to seek out ice inside these dark regions on the Moon, which haven't seen sunlight in billions of years. Should the lasers hit bare rock or regolith (broken rock and dust), the light will reflect back to the spacecraft. But if the target absorbs the light, that would indicate the presence of water ice. The greater the absorption, the more ice there may be.

The science data collected by the mission will be compared with observations made by other lunar missions to help reveal the distribution of surface water ice on the Moon for potential use by future astronauts.

Lunar Flashlight will use a new kind of "green" propellant that is safer to transport and store than the commonly used in-space propellants such as hydrazine. In fact, the SmallSat will be the first interplanetary spacecraft to use this propellant, and one of the mission's primary goals is to demonstrate this technology for future use. The propellant was successfully tested on a previous NASA technology demonstration mission in Earth orbit.

posted 01-18-2023 05:13 PM               

NASA's Lunar Flashlight Team Assessing Spacecraft's Propulsion System

NASA's Lunar Flashlight mission successfully launched on Dec. 11, 2022, to begin its four-month journey to the Moon, where the small satellite, or SmallSat, will test several new technologies with a goal of looking for hidden surface ice at the lunar South Pole. While the SmallSat is largely healthy and communicating with NASA's Deep Space Network, the mission operations team has discovered that three of its four thrusters are underperforming.

The mission team, which first observed the reduced thrust three days after launch, is working to analyze the issue and provide possible solutions. During its cruise, Lunar Flashlight's propulsion system has operated for short-duration pulses of up to a couple seconds at a time. Based on ground testing, the team thinks that the underperformance might be caused by obstructions in the fuel lines that may be limiting the propellant flow to the thrusters.

The team plans to soon operate the thrusters for much longer durations, hoping to clear out any potential thruster fuel line obstructions while carrying out trajectory correction maneuvers that will keep the SmallSat on course to reach its planned orbit around the Moon. In case the propulsion system can't be restored to full performance, the mission team is drawing up alternative plans to accomplish those maneuvers using the propulsion system with its current reduced-thrust capability. Lunar Flashlight will need to perform daily trajectory correction maneuvers starting in early February to reach lunar orbit about four months from now.

Swooping low over the Moon's surface, the briefcase-size SmallSat will use a new laser reflectometer built with four near-infrared lasers to shine a light into the permanently shadowed craters at the lunar South Pole to detect surface ice. To achieve this goal with the limited amount of propellent it's built to carry, Lunar Flashlight will employ an energy-efficient near-rectilinear halo orbit, taking it within 9 miles (15 kilometers) of the lunar South Pole and 43,000 miles (70,000 kilometers) away at its farthest point.

Only one other spacecraft has employed this type of orbit: NASA's Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (CAPSTONE) mission, which launched in June 2022 to a different near-rectilinear halo orbit, the same one that is planned for Gateway. CAPSTONE also experienced difficulties during its journey to the Moon, and some of the NASA teams who helped the SmallSat reach its planned orbit are lending their expertise to help resolve Lunar Flashlight's thruster issues.

Managed by NASA's Jet Propulsion Laboratory in Southern California, Lunar Flashlight is the first interplanetary spacecraft to use a new kind of "green" propellant, called Advanced Spacecraft Energetic Non-Toxic (ASCENT), that is safer to transport and store than the commonly used propellants such as hydrazine. One of the mission's primary goals is to demonstrate this technology for future use. The propellant was successfully tested with a previous NASA technology demonstration mission in Earth orbit.

Other systems on Lunar Flashlight are performing well, including the never-before-flown Sphinx flight computer, developed by JPL as a low-power, radiation-tolerant option for SmallSats. Also performing as designed, Lunar Flashlight's upgraded Iris radio – which is used to communicate with the Deep Space Network – features a new precision navigation capability that future small spacecraft will use to rendezvous and land on other solar system bodies. Additional new and groundbreaking systems, such as the mission's laser reflectometer, will be tested in the coming weeks before the mission enters lunar orbit.

posted 02-09-2023 02:05 PM               

NASA Eyes New Lunar CubeSat Orbit, Propulsion Challenges Continue

NASA's Lunar Flashlight CubeSat launched on Dec. 11, 2022, to demonstrate several new technologies with a stretch science goal of detecting surface ice at the Moon's South Pole. Shortly into Lunar Flashlight's journey, the mission operations team discovered three of its four thrusters were underperforming.

Among the steps taken to analyze the issue and find possible solutions, the mission performed tests to determine whether the one fully functional thruster could provide adequate thrust to guide the spacecraft into its planned orbit. To that end, team members at NASA's Jet Propulsion Laboratory in Southern California and Georgia Tech devised a creative maneuvering technique using one thruster: The spacecraft was spun at a rate of 6 degrees per second, or one revolution per minute, around its directed axis. Then the thruster was fired while commanding the spacecraft to remain pointed in the right direction. There was potential after 20 days, these mini-trajectory correction maneuvers would guide Lunar Flashlight to its planned near-rectilinear halo orbit around the Moon.

The team successfully completed quite a few 10-minute sequences on the single thruster, but soon after, that thruster also experienced a rapid loss in performance, and it became clear that the thrust being delivered was not enough to make it to the planned orbit.

The NASA JPL and Georgia Tech team is developing a new plan to get to the Moon. Because achieving an optimal near-rectilinear halo orbit appears unlikely, the Lunar Flashlight team decided to attempt lunar flybys using any remaining thrust the propulsion system can deliver. This new attempt is designed to get the CubeSat into high Earth orbit, which includes periodic flybys of the lunar South Pole once a month to collect data. The team plans to begin maneuvers on Thursday, and, if successful, the expected first science pass will now be in June.

While Lunar Flashlight faces significant challenges in its goal of getting to the Moon, testing its new propulsion system in space fulfills one of the mission's objectives and will support future technology development. The mission's miniaturized propulsion system is a technology demonstration that has never been flown in space before. Technology demonstrations are high-risk, high-reward endeavors intended to push the frontiers of space technology. The lessons learned from these challenges will help to inform future missions that further advance this technology.

The rest of the CubeSat's onboard systems are fully functional, and the mission recently successfully tested its four-laser reflectometer. This mini-instrument is the first of its kind and is designed and calibrated to seek out surface ice inside the permanently shadowed craters at the Moon's South Pole.

Lunar Flashlight is funded by the Small Spacecraft Technology program in NASA's Space Technology Mission Directorate.

posted 05-12-2023 04:01 PM               

NASA Calls End to Lunar Flashlight After Some Tech Successes

While the CubeSat couldn't reach the lunar South Pole to help seek ice, it fulfilled several technology goals that will empower future missions for the benefit of humanity.

NASA's Lunar Flashlight launched on Dec. 11, 2022, to demonstrate several new technologies, with an ultimate goal to seek out surface ice in the permanently shadowed craters of the Moon's South Pole. Since then, the briefcase-size satellite's miniaturized propulsion system – the first of its kind ever flown – proved unable to generate enough thrust to get into lunar orbit, despite months of effort by the operations team. Because the CubeSat cannot complete maneuvers to stay in the Earth-Moon system, NASA has called an end to the mission.

NASA relies on technology demonstrations to fill specific knowledge gaps and to test new technologies. Used for the first time beyond Earth's orbit, Lunar Flashlight's propulsion system and green fuel were such demonstrations. Although the propulsion system was unable to produce the desired thrust – likely because of debris buildup in the thruster fuel lines – newly developed propulsion system components exceeded performance expectations.

Also surpassing expectations were Lunar Flashlight's never-before-flown Sphinx flight computer – a low-power computer developed by NASA's Jet Propulsion Laboratory in Southern California to withstand the radiation of deep space – and the spacecraft's upgraded Iris radio. Featuring a new precision navigation capability, the radio can be used by future small spacecraft to rendezvous and land on solar system bodies.

"Technology demonstrations are, by their nature, higher risk and high reward, and they're essential for NASA to test and learn," said Christopher Baker, program executive for Small Spacecraft Technology in the Space Technology Mission Directorate at NASA Headquarters in Washington. "Lunar Flashlight was highly successful from the standpoint of being a testbed for new systems that had never flown in space before. Those systems, and the lessons Lunar Flashlight taught us, will be used for future missions."

The mission's miniaturized four-laser reflectometer, a science instrument that had never flown before, either, also tested successfully, giving the mission's science team confidence that the laser would have been able to detect ice if it were present at the lunar surface.

"It's disappointing for the science team, and for the whole Lunar Flashlight team, that we won't be able to use our laser reflectometer to make measurements at the Moon," said Barbara Cohen, the mission's principal investigator at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "But like all the other systems, we collected a lot of in-flight performance data on the instrument that will be incredibly valuable to future iterations of this technique."

Propulsion System Performance Challenges

Despite the mission's technological wins, Lunar Flashlight's miniaturized propulsion system struggled to provide sufficient thrust to put the CubeSat on course for the planned near-rectilinear halo orbit that would have given the spacecraft weekly flybys of the Moon's South Pole.

The team suspects that debris obstructed the fuel lines, causing the diminished and inconsistent thrust. The miniaturized propulsion system included an additively manufactured fuel feed system that likely developed the debris – such as metal powder or shavings – and obstructed fuel flow to the thrusters, limiting their performance. Although the team devised a creative method for using just one thruster to maneuver the spacecraft, Lunar Flashlight needed more consistent thrust to reach its planned orbit.

The operations team calculated a new orbit that could be reached using the spacecraft's small amount of potential remaining thrust. The plan called for putting the CubeSat on a path that would place it in orbit around Earth rather than the Moon, with monthly flybys of the lunar South Pole. While this would have meant fewer flybys, the spacecraft would have flown closer to the surface.

With the mission running out of time to arrive at the needed orbit, the operations team tried to dislodge any debris from the fuel lines by increasing the fuel pressure well beyond the propulsion system's designed capacity. Despite limited success, the required trajectory correction maneuvers couldn't be completed in time.

"The student operations team at Georgia Tech, with assistance from JPL and NASA's Marshall Space Flight Center, rose to the challenge and came up with an incredible array of inventive techniques to utilize what tiny amount of thrust Lunar Flashlight's propulsion system could deliver," said John Baker, Lunar Flashlight project manager at JPL. "We learned a lot and honed new methods and strategies for working with tiny spacecraft."

After having traveled out past the Moon, Lunar Flashlight is now moving back toward Earth and will fly past our planet with a close approach of about 40,000 miles (65,000 kilometers) on May 17. The CubeSat will then continue into deep space and orbit the Sun. It continues to communicate with mission operators, and NASA is weighing options for the future of the spacecraft.

More About the Mission

Lunar Flashlight is managed for NASA by JPL, a division of Caltech in Pasadena, California. The CubeSat is operated by Georgia Tech, including graduate and undergraduate students. The Lunar Flashlight science team is led by NASA Goddard and includes team members from the University of California, Los Angeles; Johns Hopkins University Applied Physics Laboratory; and the University of Colorado.

The CubeSat's propulsion system was developed by NASA Marshall in Huntsville, Alabama, with development and integration support from Georgia Tech. NASA's Small Business Innovation Research program funded component development from small businesses including Plasma Processes Inc. (Rubicon) for thruster development, Flight Works for pump development, and Beehive Industries (formerly Volunteer Aerospace) for specific 3D-printed components. The Air Force Research Laboratory also contributed financially to the development of Lunar Flashlight's propulsion system. Lunar Flashlight is funded by the Small Spacecraft Technology program based at NASA's Ames Research Center in Silicon Valley and within NASA's Space Technology Mission Directorate.