NASA's Maven spacecraft, which began orbiting the planet on Sept. 21, maintained low-data-rate communications during the comet's flyby, according to the space agency. Maven captured information about the composition of the gases and dust the comet was releasing as it passed by, while also investigating the interaction between the material and the planet's atmosphere.
A downlink of data from the Maven orbiter has already begun.
NASA's Mars Reconnaissance Orbiter also maintained communications with Earth during the Siding Spring's flyby. Its own downlink, which may take days because of the amount of data to send, also has begun.
This orbiter used three instruments to observe the comet for several days as it approached Mars and will continue to take measurements for the next few days as it continues on its path.
Scientists have described the comet's close approach to Mars as a "once-in-a-lifetime opportunity" to study a comet and its affect on the planet's atmosphere, as well as to gain clues about the beginnings of our solar system.
"This is a cosmic science gift that could potentially keep on giving, and the agency's diverse science missions will be in full receive mode," said John Grunsfeld, astronaut and associate administrator for NASA's Science Mission Directorate, in a statement made earlier this month. "This particular comet has never before entered the inner solar system, so it will provide a fresh source of clues to our solar system's earliest days."
The Siding Spring comet — which came from the Oort Cloud, a spherical region of space surrounding our sun — is made up of a giant swarm of icy objects believed to be material left over from the formation of the solar system.
It will be the first comet from that region scientists have been able to study up close, giving them a chance to learn more about the materials, including water and carbon compounds, that existed during the formation of the solar system 4.6 billion years ago, NASA noted.
Sign up for CIO Asia eNewsletters.