Three NASA Mars orbiters – Mars Odyssey, Mars Reconnaissance Orbiter, MAVEN orbiter – and two Mars rovers are part of a campaign to study Comet Siding Spring and possible effects on the planet’s atmosphere from gases and dust released by the comet.
This image shows Comet 2013 A1, also known as Siding Spring, as captured by Wide Field Camera 3 on NASA’s Hubble Space Telescope. Image credit: NASA / ESA / J.-Y. Li, Planetary Science Institute.
On 19 October 2014, Siding Spring hurtled past the Red Planet at 56 km per second, coming within about 139,500 km. That is equivalent to about one-third of the distance between our planet and the Moon.
The closest approach by the comet’s nucleus came at about 2:27 p.m. EDT (11:27 a.m. PDT, 6:27 p.m. GMT, 8:27 p.m. CET).
The period when dust from the comet was most likely to reach Mars and the orbits of NASA’s three orbiters – including newest Mars Atmosphere and Volatile Evolution (MAVEN) orbiter – peaked about 100 minutes later.
MAVEN reported back to Earth in good health after about 3 hrs of precautions against a possible collision with comet’s dust particles.
Downlink of data has begun from yesterday’s observations of the comet and Mars’ atmosphere. Some observations are designed to provide information about the composition of the gases and dust being released by the comet; others are investigating possible interaction between material from the comet and the atmosphere.
Planned science observations of Siding Spring by NASA’s spacecraft and rovers. Image credit: NASA.
Mars Reconnaissance Orbiter, which has sent home more data about Mars than all other missions combined, is also now providing data about a comet that has buzzed the planet.
The orbiter also continues operating in good health after sheltering behind the planet during the half hour.
It maintained radio communications with Earth throughout the comet’s closest approach, at 2:27 p.m. EDT (11:27 a.m. PDT, 6:27 p.m. GMT, 8:27 p.m. CET), and the peak dust-risk period centered about 100 minutes later.
Following the critical period of dust flux, the orbiter is communicating at 1.5 megabits per second with NASA’s Deep Space Network.
Downlink of data has begun from comet observations by three instruments on the orbiter – the High Resolution Imaging Science Experiment (HiRISE), the Compact Imaging Spectrometer for Mars (CRISM), and the Context Camera (CTX). The full downlink may take days.
These instruments also observed the comet for days before the flyby and will continue to make observations of it in the next few days.
The orbiter’s other three instruments – the Mars Climate Sounder (MCS), the Mars Color Imager (MARCI) and the Mars Shallow Radar (SHARAD) – are being used to study possible effects of gas and dust in the comet’s tail interacting with the atmosphere of Mars.
Mars Odyssey – the longest-lived robot ever sent to Mars – also came through the challenge in good health, reporting home on schedule after sheltering behind Mars from possible comet dust.
Siding Spring observations were made by the orbiter’s Thermal Emission Imaging System (THEMIS).
Resulting images are expected in coming days after the data is downlinked to Earth and processed.
THEMIS is also scheduled to record a combined image of the comet and a portion of Mars later this week.
In addition, the mission is using the spacecraft’s Neutron Spectrometer and High Energy Neutron detector to assess possible effects on Mars’ atmosphere of dust and gas from the comet.
