Remote-sensing satellite operator HawkEye 360 is the latest to encounter difficulties in space due to an "irreparable" failure of propulsion systems provided by Austria-based Enpulsion, exacerbated by heightened solar activity.
While HawkEye declined to disclose its propulsion provider to TechCrunch, an April 2022 letter from HawkEye to the FCC (Federal Communications Commission) indicates that the affected satellites are equipped with Enpulsion's IFM Nano Thruster propulsion system.
On July 24, HawkEye sought temporary permission from the FCC to operate three of its satellites, known as Cluster 4, at a lower altitude. Additionally, the company filed a separate request for permanent authority to operate its constellation at orbital altitudes ranging from 400 to 615 kilometers, attributing the need to propulsion failures.
According to HawkEye's request, "The Cluster 4 spacecraft are currently operating at an orbital altitude of approximately 477 km, as a result of failures in the propulsion systems of each of the Cluster 4 spacecraft. The company has unsuccessfully tried to remedy these failures and recently concluded that the propulsion system failures are irreparable."
Having already phased out the use of Enpulsion's systems, HawkEye transitioned to a water-based propulsion system developed by Bradford Space in March. This change commenced with Cluster 7 and will extend to all future satellites. Cluster 7 was successfully launched into orbit in April, expanding HawkEye's constellation to 21 spacecraft (including the three encountering issues).
As per NASA, we are currently entering the solar maximum phase, which is the period in the solar cycle when the sun's activity reaches its peak. This heightened solar activity, often leading to strong geomagnetic storms, can pose challenges for spacecraft, including causing heightened atmospheric drag that accelerates their orbital decay.
Last week, TechCrunch reported that certain Capella Space satellites were beginning to experience premature deorbiting due to solar activity and complications related to third-party propulsion systems.
In a statement provided to TechCrunch, HawkEye confirmed that the Cluster 4 satellites remain operational apart from the propulsion issue. Enpulsion did not respond to TechCrunch's request for comment.
HawkEye stated, "The Cluster 4 satellites are not at risk of immediate deorbiting and are continuing to gather data and effectively serve our clients. Although they were placed at a lower orbital altitude and experienced a propulsion system anomaly that has reduced their potential mission duration, these satellites are still projected to function within the parameters of their intended design lifespan. Our overall constellation structure is resilient and accounts for variations in mission duration across our clusters, considering deployment altitude, anomalies, and space weather."
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