The cruise phase begins after the spacecraft separates from the rocket, soon after launch. The spacecraft departs Earth at a speed of about 24,600 mph (about 39,600 kph). The trip to Mars will take about seven months and about 300 million miles (480 million kilometers). During that journey, engineers have several opportunities to adjust the spacecraft’s flight path, to make sure its speed and direction are best for arrival at Jezero Crater on Mars. The first tweak to the spacecraft’s flight path happens about 15 days after launch.
The Trip to MarsEngineers on Earth keep close tabs on the mission during cruise. Major activities include:
- Checking spacecraft health and maintenance
- Monitoring and calibrating the spacecraft and its onboard subsystems and instruments
- Performing attitude correction turns (slight spins to keep the antenna pointed toward Earth for communications, and to keep the solar panels pointed toward the Sun for power)
- Conducting navigation activities, such as trajectory correction maneuvers, to determine and correct the flight path and train navigators before atmospheric entry. The last three correction maneuvers are scheduled during approach.
- Preparing for entry, descent, and landing (EDL) and surface operations, a process which includes tests of communications, including the communications to be used during EDL.
The mission is timed for launch when Earth and Mars are in good positions relative to each other for landing on Mars. That is, it takes less power to travel to Mars at this time, compared to other times when Earth and Mars are in different positions in their orbits. As Earth and Mars orbit the Sun at different speeds and distances, once about every 26 months, they are aligned in a way that allows the most energy-efficient trip to Mars.
Fine-Tuning the Flight Path to Mars
During the cruise phase, engineers have five opportunities (plus one backup maneuver and one contingency maneuver) to adjust the flight path. During these trajectory correction maneuvers, engineers will calculate the spacecraft’s location and command eight thrusters on the cruise stage to fire for a specific amount of time needed to tweak the path.
The maneuvers are very important because years of careful planning led to selection of Jezero Crater as the landing site on Mars, and fine-tuning the flight path ensures that the spacecraft will enter the Mars atmosphere at just the right spot to land inside Jezero crater.
The final 45 days leading up to the landing make up the approach phase. This phase primarily involves navigation activities and getting the spacecraft ready for Entry, Descent and Landing. This is when the final three trajectory correction maneuvers may be performed, if needed.
|Date (subject to change)||Trajectory Correction Maneuvers||Activity|
|Aug. 14, 2020
15 days after launch
|TCM-1||Point spacecraft toward Mars, fine-tune its flight path after launch.|
|Sept. 28, 2020
60 days after launch
|Dec. 20, 2020
60 days before landing
|TCM-3||To make sure the spacecraft travels at the right speed and direction to arrive at the correct location at the top of the Martian atmosphere before landing.|
|Feb. 10, 2021
8.6 days before landing
|TCM-4||Refine flight path.|
|Feb. 16, 2021
2.6 days before landing
|Feb. 17, 2021
1.6 days before landing
|TCM-5X||Backup maneuver, if needed.|
|Feb. 18, 2021
9 hours before landing
|TCM-6||Contingency maneuver, if needed. Final opportunity to adjust where the spacecraft will enter the Mars atmosphere.|