Things Are Not Looking Good For NASA’s CAPSTONE Spacecraft
A few months ago we watched Rocket Lab’s historic mission with NASA. Here, the company managed to successfully send the CAPSTONE payload on a trajectory for the Moon, using Electron and a Lunar Photon. Unfortunately for NASA, it seems the CAPSTONE spacecraft has experienced nothing but complications throughout its entire journey so far.
Starting just a few days after the initial successful launch, the agency reported communication issues with the spacecraft. Between then and now, more problems have come up including the most recent which NASA just reported. Specifically, the agency gave an update pointing out that teams are continuing to work toward the recovery of the spacecraft orientation control. Not to mention a host of other problems that are putting the mission at risk.
This is especially concerning as CAPSTONE has a very important job apart of Artemis. The spacecraft is intended to test a unique, elliptical lunar orbit, the same one meant for Gateway, Artemis’s future lunar space station. Here I will go more in-depth into some of the recent complications, what exactly went wrong, what to expect in the future, and more.
CAPSTONE Problems
Most recently, it looks as if NASA has lost access to CAPSTONE’s orientation control. Specifically, the agency reported on September 30th that the CAPSTONE mission team is continuing to work toward recovery of the spacecraft orientation control. This work includes collecting information from the spacecraft, running simulations, and refining recovery plans. However, this is just the most recent problem that the agency has run into. In reality, problems began to arise soon after the spacecraft separated from Rocket Lab’s hardware.
The official launch date was June 28th. Only about a week later, the spacecraft ran into its first issue. On July 5th, NASA reported that following successful deployment and start of spacecraft commissioning on July 4th, the CAPSTONE spacecraft experienced communications issues while in contact with the Deep Space Network. As a result of the communications issues, CAPSTONE’s first trajectory correction maneuver, originally scheduled for the morning of July 5th, was delayed. Fortunately, the next day on July 6th, NASA was able to reestablish communication. During the commissioning of CAPSTONE, the Deep Space Network team noted inconsistent ranging data. While investigating this, the spacecraft operations team attempted to access diagnostic data on the spacecraft’s radio and sent an improperly formatted command that made the radio inoperable. The spacecraft fault detection system should have immediately rebooted the radio but did not because of a fault in the spacecraft flight software. This was the cause of the communication error. CAPSTONE’s autonomous flight software system eventually cleared the fault and brought the spacecraft back into communication with the ground, allowing the team to implement recovery procedures and begin commanding the spacecraft again.
With this initial problem solved, the spacecraft went on to successfully perform a few trajectory maneuvers on its journey to the Moon. Unfortunately, a few months later more issues began to arise. On September 10th NASA reported that the CAPSTONE spacecraft executed a planned trajectory correction maneuver on Thursday evening, Sept. 8, and CAPSTONE mission controllers have since obtained telemetry confirming that an issue put the spacecraft in safe mode near the end of the maneuver. A few days later they gave more details highlighting that CAPSTONE suffered an issue that caused the spacecraft to tumble beyond the capacity of the onboard reaction wheels to control and counter. CAPSTONE was attempting to communicate with the ground for approximately 24 hours before any telemetry was recovered. After data was received, mission controllers found that the spacecraft was tumbling, the onboard computer systems were periodically resetting, and the spacecraft was using more power than it was generating from its solar panels.
At the time, while work was ongoing to diagnose the cause of the issue, the team was preparing CAPSTONE to attempt a detumble operation to regain attitude control of the spacecraft. This detumble operation was successfully demonstrated after separation from the launch upper stage in July. The idea being, a successful detumble would give CAPSTONE control over its orientation, allowing it to orient the solar panels to the Sun to fully charge the batteries of the power used during the detumble. The spacecraft would then orient to the ground and await further instructions. However, a few days later and things had not gotten any better. On September 18th NASA reported that they were still working on recovery efforts. In addition, the primary focus shifted to the temperature of the spacecraft’s propulsion system, which dropped below its operational temperature limit following the initial issue that put the spacecraft into safe mode on Sept. 8.
The next CAPSTONE update came on September 21st. NASA pointed out that the operations team had been performing ground and spacecraft testing in preparation for an attempt to stop CAPSTONE’s spin. This operation would return the spacecraft to normal status and will be attempted when preparations and testing are complete. However, for the time being, the spacecraft was still spinning. This leads us to the most recent update we have received which is not promising. As partially mentioned prior, currently, the agency is trying to gain access to the spacecraft orientation control. NASA also said that CAPSTONE is power positive – meaning it is generating more power from its solar panels than the spacecraft systems are using – and remains in a stable condition on track to the Moon. This being said, it’s not looking good as CAPSTONE continues to spin with NASA unable to correct it.
CAPSTONE Importance
Now that we know exactly what’s going on with the CAPSTONE spacecraft, we can take a closer look at its importance and why a possible failed mission would be a major inconvenience. CAPSTONE is a microwave oven–sized CubeSat weighing just 55 pounds meant to serve as the first spacecraft to test a unique, elliptical lunar orbit. Specifically, it’s supposed to act as a pathfinder for Gateway, a Moon-orbiting outpost that is part of NASA’s Artemis program, CAPSTONE is meant to help reduce risk for future spacecraft by validating innovative navigation technologies and verifying the dynamics of this halo-shaped orbit. The orbit, formally known as a near rectilinear halo orbit (NRHO), is significantly elongated. Its location at a precise balance point in the gravities of Earth and the Moon, offers stability for long-term missions like Gateway and requires minimal energy to maintain. CAPSTONE’s orbit also establishes a location that is an ideal staging area for missions to the Moon and beyond. The orbit will bring CAPSTONE within 1,000 miles of one lunar pole on its near pass and 43,500 miles from the other pole at its peak every seven days, requiring less propulsion capability for spacecraft flying to and from the Moon’s surface than other circular orbits.
After a four-month journey to its target destination, right now it’s about 3 months in, CAPSTONE will orbit this area around the Moon for at least six months to understand the characteristics of the orbit. Specifically, it will validate the power and propulsion requirements for maintaining its orbit as predicted by NASA’s models, reducing logistical uncertainties. Its also meant to demonstrate the reliability of innovative spacecraft-to-spacecraft navigation solutions as well as communication capabilities with Earth. The NRHO provides the advantage of an unobstructed view of Earth in addition to coverage of the lunar South Pole.
In order to test these new navigation capabilities, CAPSTONE has a second dedicated payload flight computer and radio that will perform calculations to determine where the CubeSat is in its orbital path. Circling the Moon since 2009, NASA’s Lunar Reconnaissance Orbiter (LRO) will serve as a reference point for CAPSTONE. The intention is for CAPSTONE to communicate directly with LRO and utilize the data obtained from this crosslink to measure how far it is from LRO and how fast the distance between the two changes, which in turn determines CAPSTONE’s position in space. This peer-to-peer information will be used to evaluate CAPSTONE’s autonomous navigation software. If successful, this software, referred to as the Cislunar Autonomous Positioning System (CAPS), will allow future spacecraft to determine their location without having to rely exclusively on tracking from Earth. This capability could enable future technology demonstrations to perform on their own without support from the ground and allow ground-based antennas to prioritize valuable science data over more routine operational tracking. Unfortunately, as of right now, while still on track to reach the Moon, CAPSTONE is spinning and NASA still lacks the ability to fix it. If NASA were to lose full access to this spacecraft, it could mean a majority of the information meant to be gathered could be lost.
Conclusion
NASA is trying to return humans to the Moon apart of Artemis. Not long ago we watched Rocket Lab launch the CAPSTONE payload on a journey to the Moon. Over the past few months however, the spacecraft has experienced quite a few issues. We will have to wait and see how it progresses and the impact it has on the space industry.
