The sun's gravitational influence plays a significant role in shaping not just spacecraft trajectories to Mars (as well as to everywhere else in the solar system), but also the relative movement of the two planets, so Perseverance's route to the Red Planet follows a curved trajectory rather than an arrow-straight path.
Julie Kangas, a navigator working on the Perseverance rover mission at NASA's Jet Propulsion Laboratory in southern California, explained, "At 1:40pm Pacific Time today, our spacecraft will have just as many miles in its metaphorical rear view mirror as it will out its metaphorical windshield. While I don't think there will be cake, especially since most of us are working from home, it's still a pretty neat milestone. Next stop, Jezero Crater."
At the current distance, it takes two minutes, 22 seconds for a transmission to travel from mission controllers at JPL via the Deep Space Network to the spacecraft. By time of landing, Perseverance will have covered 470.8 million kilometres, and Mars will be about 209 million kilometres away from Earth; at that point, a transmission will take about 11.5 minutes to reach the spacecraft.
Kangas added, "Although we're halfway into the distance we need to travel to Mars, the rover is not halfway between the two worlds. In straight-line distance, Earth is 42.7 million kilometres behind Perseverance and Mars is 28.8 million kilometres in front."
The mission team continues to check out spacecraft systems big and small during interplanetary cruise. Perseverance's RIMFAX and MOXIE instruments were tested and determined to be in good shape on 15 October and MEDA got a thumbs up on 19 October. There was even a line item to check the condition of the X-ray tube in the PIXL instrument on 16 October, which also went as planned.
Keith Comeaux, deputy chief engineer for the Mars 2020 Perseverance rover mission, added, "If it is part of our spacecraft and electricity runs through it, we want to confirm it is still working properly following launch. Between these checkouts – along with charging the rover's and Mars Helicopter's batteries, uploading files and sequences for surface operations, and planning for and executing trajectory correction manoeuvres – our plate is full right up to landing."
A key objective of Perseverance's mission on Mars is astrobiology, including the search for signs of ancient microbial life. The rover will characterise the planet's geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and cache Martian rock and regolith (broken rock and dust).
Subsequent missions, currently under consideration by NASA in co-operation with ESA (European Space Agency), would send spacecraft to Mars to collect these cached samples from the surface and return them to Earth for in-depth analysis.
The Mars 2020 mission is part of a larger program that includes missions to the Moon as a way to prepare for human exploration of the Red Planet. Charged with returning astronauts to the moon by 2024, NASA will establish a sustained human presence on and around the moon by 2028 through NASA's Artemis lunar exploration plans.
JPL, which is managed for NASA by Caltech in Pasadena, California, built and manages operations of the Perseverance and Curiosity rovers.
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