NanoAvionics MP42 satellite survives impact with object in orbit

Vilnius, Lithuania (SPX) Nov 03, 2024
Our MP42 satellite, which launched into low Earth orbit (LEO) two and a half years ago aboard the SpaceX Transporter-4 mission, recently took an unexpected hit from a small piece of space debris or micrometeoroid. The impact created a 6 mm hole, roughly the size of a chickpea, in one of its solar panels. Despite this damage, the satellite continued performing its mission without interruption, and we only discovered the impact thanks to an image taken by its onboard selfie camera in October of 2024. It is challenging to pinpoint exactly when the impact occurred because MP42's last selfie was taken a year and a half ago, in April of 2023.

Whether this impact was from a micrometeoroid or a piece of space debris, the collision highlights the need for responsible space operations in orbit and makes us reflect on satellite resilience against these types of events.

How Much Space Debris Is There In Orbit?
Today, nearly 3 million kg of man-made objects orbit within 2000 km of Earth, including active and inactive satellites and rocket stages. A smaller amount of mass, about 60000 kg, is in the remaining 9000 objects currently being tracked by space surveillance sensors. Comparatively, only a total of 200 kg of meteoroid mass is present within 2000 km of Earth's surface at any given moment.

According to data from NASA's Long Duration Exposure Facility (LDEF), launched in 1984, small particles in orbit are common. During its nearly six-year mission, the LDEF spacecraft recorded up to 140 significant impact craters per square meter each year, with impact craters ranging from 0.1 mm to 3 mm in diameter. While natural micrometeoroid collisions are relatively stable, human-made debris poses a unique challenge by accumulating over time.

Despite these seemingly large numbers, the International Space Station (ISS), the largest structure in orbit with the largest safety area of any spacecraft, which spans 4 by 50 by 50 kilometers (2.5 by 30 by 30 miles), has only performed 32 collision avoidance maneuvers to dodge space debris in 23 years between 1999 and 2022.

In our own experience, despite launching nearly 50 satellites over more than a decade, we have only had to perform a handful of collision avoidance maneuvers. Most recently, in 2024, our mission operators executed a sequence of three firings using the satellite's electric propulsion system, which lowered our customer's collision probability with another object by several orders of magnitude from 1.99e-4 to 5.94e-8.

However, with more satellites entering orbit each year, this low collision rate may not last if satellite manufacturers and operators do not take action to reduce the amount of generated debris today.

The Role of the Zero Debris Charter
As signatories and community members of the Zero Debris Charter, initiated by ESA, we're committed to the industry's ambitious goal of achieving zero debris by 2030. This Charter is a global initiative that, as of the time of writing, brings together more than 100 organizations worldwide to set measurable debris reduction goals, with targets built through open collaboration.

The Charter represents a shared vision for sustainable space operations, setting both high-level principles and technical targets to guide space safety efforts for years to come, emphasizing both immediate and long-term measures.

By joining this initiative, we're helping to ensure that NanoAvionics' satellites and those from our customers operate responsibly and contribute to a safer future in space.

Ways to Minimize Space Debris
We utilize space situational awareness platforms that use AI and machine learning to analyze space traffic data from multiple sources, providing precise collision predictions and optimized maneuver strategies. This ensures we can act quickly if any of our satellites are at risk. In addition to collision avoidance, we take several other steps to keep our orbits as clean as possible:

+ Our satellites undergo rigorous total ionizing dose (TID), heavy ion, and proton beam radiation testing to ensure they operate reliably and don't become debris due to malfunctions caused by radiation.

+ We use clean release mechanisms, such as burn wires and frangible bolts, for deploying solar panels, antennas, and other components to avoid producing debris.

+ For satellites with mission lifetimes longer than five years, we equip them with propulsion systems for controlled deorbiting, reducing long-term debris.

+ Some of the customer missions we enabled contribute to tracking and removing debris, actively helping to make space safer for all users.

Improving Satellite Design for Space Resilience
Our recent experience with the MP42 also brings up the discussion about how satellite design can reduce the impact of space debris on overall mission success.

A few examples could be considering positioning sensitive components, like star trackers, within the satellite frame or on sides that mostly face away from the satellite's velocity vector to reduce impact risks.

Additionally, examining how mission operations could reduce payload, such as camera optics, exposure to the primary flow of space debris. NASA's LDEF experiment we mentioned earlier showed that spacecraft encounter debris rughly 10 times more frequently on the side that is exposed to the satellite's velocity vector.

By adjusting satellite designs and concepts of operation (CONOPS) to protect vulnerable components, we can further improve our satellites' resilience in orbit.