May 26, 2018
NASA's InSight Mars Lander Performs First Engine Burn To Set Its Course For The Red Planet

NASA has news about the InSight Mars lander currently hurtling through space on its way to the Red Planet. The InSight lander has fired up its engines for the first time in space to adjust its course toward Mars, the space agency reported earlier this week.

This first engine burn, which involved half of the lander's eight thrusters, is the most important in a series of six trajectory correction maneuvers meant to ensure that the InSight Mars lander reaches its designated landing site on November 26.

According to NASA, the four thrusters were fired on May 22 for about 40 seconds and changed InSight's velocity by about 8.5 mph (13.7 km/h).

The launch press kit for NASA's historic InSight mission indicates that the lander's next course-adjusting maneuver is slated for July, with the subsequent engine burns scheduled for October 12, November 11, November 18, and November 25.

On the day of the touchdown, when the InSight lander is just hours away from Mars, the planet's gravity will take over and reel in the lander, NASA officials explained. The spacecraft will then prepare for its entry, descent and landing sequence, which will be relayed back to Earth by the twin MarCO satellites that shared a ride with the InSight Mars lander on the same United Launch Alliance Atlas V rocket on May 5.

The reason why the InSight lander needs to perform these trajectory-correction maneuvers is that Mars-bound rockets are typically launched "just off-target," NASA points out.

In this way, the rocket is able to fly off into space and deliver its payload without actually coming close to Mars.

This is necessary because, unlike the spacecraft that will actually touch the Martian surface and which is meticulously cleaned before launch, the rocket's upper stage, called a Centaur, isn't scrubbed down to minimize the chances of Mars' contamination with Earth microbes.

While the four thrusters are busy performing their trajectory correction maneuvers over the next months, the remaining thrusters are not just standing idly by, notes This group of four thrusters fires autonomously on a daily basis, to make sure that InSight's antenna remains oriented toward Earth and that its solar panels keep facing the sun.

These small, daily engine firings play an important part in maintaining orientation, but they can "also introduce errors that navigators have to account for and counterbalance," NASA explains.

As a result, the InSight navigation team is constantly keeping track of these background engine burns, says llen Halsell, chief of InSight's navigation team at NASA's Jet Propulsion Laboratory in Pasadena, California.

"Everyone has been working hard since launch to assess what these small forces have done to the trajectory."
Halsell revealed that the team has spent "lots of hours" looking into the matter.

"For engineers, it's a very interesting problem, and fun to try to figure out," he added.

The InSight Mars lander will be the first spacecraft to take a peek under the Martian crust and study the planet's seismic activity, also known as "marsquakes." Additionally, the lander is equipped with a heat flow probe that will "take Mars' pulse" and measure the planet's temperature.