Spaceflight Insider

Correction maneuver puts NASA’s InSight lander on path to Mars

NASA's InSight spacecraft is currently cruising toward Mars. On May 22, 2018, it performed its first course correction guiding it to the Red Planet. Image Credit: NASA/JPL-Caltech

NASA’s InSight spacecraft is currently cruising toward Mars. On May 22, 2018, it performed its first course correction guiding it to the Red Planet. Image Credit: NASA/JPL-Caltech

The first and largest of six planned course correction maneuvers directing NASA’s Interior Exploration using Seismic Investigations, Geodesy, and Heat Transport (InSight) lander to Mars was successfully completed Tuesday, May 22, 2018.

Launched May 5, 2018, atop an Atlas V 401 rocket from Vandenberg Air Force Base in California and scheduled to land on the Red Planet Nov. 26, 2018, InSight fired its thrusters for the first time to adjust its flight path and direct it to Mars. While rocket launches allow spacecraft to escape Earth’s gravity, subsequent moves known as trajectory correction maneuvers are needed to put them on a precise course to their target destinations.

Spacecraft antennas send radio signals containing accurate details about their positions and velocities back to Earth via NASA’s Deep Space Network (DSN), a system of antennas strategically positioned in three locations around the globe to assure that spacecraft are always in range of at least one. DSN antennas are also used to transmit information to spacecraft and play an important role for mission navigation teams.

Based at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, InSight’s navigation team use data returned via the DSN to refine computer models used to plot the lander’s journey.

“Navigation is all about statistics, probability, and uncertainty,” Fernando Abilleira of JPL, InSight Deputy Mission Design and Navigation Manager, said in a NASA news release. “As we gather more information on the forces acting on the spacecraft, we can better predict how it’s moving and how future maneuvers will affect its path,” 

For the May 22 maneuver, NASA said the spacecraft fired its thrusters for approximately 40 seconds, producing a velocity change of about 8.5 miles per hour (3.8 meters per second). 

According to NASA, four of InSight’s eight thrusters were fired in the maneuver. Separately from these, the space agency said the other four fire on their own every day to keep the spacecraft’s solar panels aimed at the Sun and antennas aimed at Earth. These autonomous firings cause minor changes to the spacecraft’s position that navigators have to take into account and address when planning course corrections.

“Everyone has been working hard since launch to assess what these small forces have done to the trajectory,” said InSight navigation chief Allen Halsell, also of JPL. “People have worked lots of hours to look at that. For engineers, it’s a very interesting problem, and fun to try to figure out.”




Laurel Kornfeld is an amateur astronomer and freelance writer from Highland Park, NJ, who enjoys writing about astronomy and planetary science. She studied journalism at Douglass College, Rutgers University, and earned a Graduate Certificate of Science from Swinburne University’s Astronomy Online program. Her writings have been published online in The Atlantic, Astronomy magazine’s guest blog section, the UK Space Conference, the 2009 IAU General Assembly newspaper, The Space Reporter, and newsletters of various astronomy clubs. She is a member of the Cranford, NJ-based Amateur Astronomers, Inc. Especially interested in the outer solar system, Laurel gave a brief presentation at the 2008 Great Planet Debate held at the Johns Hopkins University Applied Physics Lab in Laurel, MD.

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