NASA spacecraft avoids potential collision with Martian moon

New Delhi, India Jul 11, 2026 ALN: WASHINGTON — A NASA Mars orbiter performed a maneuver to avoid a “high probability” of colliding with the Martian moon Phobos next week, the agency reported on March 2. This incident highlights the increasing complexity of space navigation and the importance of meticulous planning in the crowded orbital environment around Mars.

The maneuver, executed on February 28, came a day after spacecraft controllers identified a potential collision between the Martian Atmosphere and Volatile Evolution (MAVEN) spacecraft and Phobos, scheduled for March 6. The orbits of the spacecraft and the moon intersect, and on that day, the two would have passed through the same point within seven seconds of each other. This close approach raised alarms among mission controllers, necessitating immediate action to ensure the safety of MAVEN and the integrity of its scientific mission.

Phobos, one of Mars' two moons, is an irregularly-shaped body measuring approximately 27 kilometers across at its longest axis. For operational purposes, spacecraft controllers model Phobos as a sphere with a radius of about 30 kilometers. Given its size and the proximity of MAVEN's orbit, NASA’s Jet Propulsion Laboratory indicated that “they had a high probability of colliding if no action were taken.” The potential collision posed a significant risk not only to MAVEN but also to the scientific data it is designed to collect about Mars' atmosphere and climate.

MAVEN fired a thruster on February 28, increasing the spacecraft's speed by 0.4 meters per second. This maneuver adjusted MAVEN's orbit to ensure that it and Phobos would now pass 2.5 minutes apart, significantly reducing the risk of collision. The successful execution of this maneuver underscores the expertise of the engineering and navigation teams at NASA and their ability to respond swiftly to unforeseen challenges in space operations.

“Kudos to the JPL navigation and tracking groups for monitoring potential collisions every day of the year, and to the MAVEN spacecraft team for executing the maneuver flawlessly,” said Bruce Jakosky, the principal investigator of the mission, in a statement. His acknowledgment reflects the collaborative efforts required in space exploration, where various teams must work in concert to achieve mission objectives and ensure safety.

This incident marks the first time that MAVEN has had to perform a collision avoidance maneuver with a moon or another spacecraft. Unlike NASA's other two Mars orbiters, Mars Odyssey and Mars Reconnaissance Orbiter (MRO), which orbit closer to the planet, MAVEN operates in an elliptical orbit that extends beyond the orbit of Phobos. This unique orbital path allows MAVEN to collect valuable scientific data about the Martian atmosphere but also increases the likelihood of intersecting with other objects in orbit around Mars.

“MAVEN's highly elliptical orbit, which crosses the altitudes of other orbits, increases the likelihood that a collision avoidance maneuver may be necessary,” explained Robert Shotwell, a key engineer for the Mars program, in a 2015 JPL statement regarding the tracking of Mars missions. “We monitor all the orbiters more closely now. While the probability of needing a maneuver is low, it is a factor we must manage.” The proactive approach taken by mission controllers reflects the evolving nature of space exploration, where the increasing number of spacecraft necessitates a more vigilant and strategic management of orbital paths.

Although Mars is less crowded than Earth, the growing number of spacecraft around the planet presents an increasing challenge for mission controllers. In addition to Mars Odyssey, MAVEN, and MRO, NASA also monitors the European Mars Express and ExoMars Trace Gas Orbiter spacecraft, as well as India's Mars Orbiter Mission, or Mangalyaan. They also keep track of the defunct Mars Global Surveyor spacecraft, which remains in orbit. The presence of multiple spacecraft conducting various scientific missions increases the complexity of orbital dynamics and necessitates continuous monitoring to prevent potential collisions.

This situation is expected to become more complex by 2021, with several more spacecraft planned for launch during the mid-2020 launch window. Countries such as China, India, and the United Arab Emirates are all preparing to launch Mars orbiters during this period, which will further populate Martian orbit and increase the likelihood of close encounters between spacecraft. Additionally, lander missions are being developed by China, NASA, and the European Space Agency (ESA), which will add another layer of complexity to the existing orbital environment.

SpaceX is also planning to launch its first Red Dragon lander mission in 2020. Initially scheduled for 2018, the mission has been delayed as the company focuses on its Falcon Heavy and Crew Dragon programs, along with a commercial human circumlunar mission announced on February 27 for a late 2018 launch. The Red Dragon mission aims to deliver payloads to the Martian surface and may involve a series of complex maneuvers to ensure the safety of both the lander and any existing orbital missions.

As the landscape of Mars exploration continues to evolve, the need for careful navigation and collision avoidance will remain a top priority for mission planners. The successful maneuver executed by MAVEN serves as a reminder of the challenges that lie ahead as more countries and organizations engage in space exploration. The lessons learned from this incident will inform future missions and contribute to the development of more sophisticated tracking and collision avoidance systems designed to protect both active spacecraft and the valuable scientific data they are tasked with collecting.

The ongoing exploration of Mars represents not only a quest for knowledge about our neighboring planet but also a broader commitment to international collaboration in space. As more nations invest in space exploration, the principles of safety, cooperation, and responsible navigation will be essential to ensuring that the benefits of space science can be realized without jeopardizing existing missions. The MAVEN incident underscores the importance of vigilance and adaptability in the face of an increasingly populated orbital environment, reinforcing the need for continued innovation in space mission planning and execution.