ESA Mars Express ready for Comet Siding Spring Encounter - Video update

Europe’s Mars orbiter and its scientific instruments will have a frontrow seat on Sunday when Comet Siding Spring grazes the Red Planet, skimming past at a little more than a third of the Moon’s distance from Earth.

Comet Siding Spring, discovered in January 2013, is less than a kilometre across and will pass Mars at 56 km/s, closing to within 139 500 km at 18:27 GMT (20:27 CEST) on 19 October.



Initially, the comet and its envelope of gas and dust were predicted to pass much closer to Mars, posing a serious risk to the fleet of orbiting spacecraft. Later observations confirmed that the miss distance will, in fact, be more comfortable, around 85,000 miles.

ESA’s teams flying Mars Express have spent months preparing for the encounter.

“In 2013, we had very little information about the comet, which was still very far and faint. In the worst case, we expected the pass to be much closer, and the comet to be much more active,” says Spacecraft Operations Manager Michel Denis.

“We designed a special mode for Mars Express that would minimise any risk due to impacts with cometary particles.

“This included turning off all instruments and non-essential onboard systems, and turning the spacecraft so as to use the large high-gain antenna as a shield.”

ESA's Mars Express Orbiter
currently orbiting Mars.

Credit: ESA

This image shows just how many satellites and probes humanity has sent to Mars. 

Some more successful than others, and we still have much to learn about our near neighbour.

NASA TRMM: Tropical Cyclone Ita's Australian encounter

This TRMM satellite rainfall map covers Tropical Cyclone Ita's life from April 1-14. 

Highest isolated rainfall was estimated around 400 mm/15.7 inches west of both Ingham and Townsville, Queensland. 

Ita's locations at 0600 UTC are shown overlaid in white. 

Credit: SSAI/NASA/JAXA, Hal Pierce

After coming ashore on April 11, Tropical Cyclone Ita dropped heavy rainfall over the weekend that caused flooding in many areas of northeastern Australia's state of Queensland.

The Tropical Rainfall Measuring Mission satellite (TRMM) satellite gathered data on rainfall that was used to create a rainfall map at NASA.

TRMM satellite

TRMM satellite is managed by both NASA and JAXA, the Japan Aerospace Exploration Agency.

At NASA's Goddard Space Flight Center in Greenbelt, Md. Hal Pierce created a TRMM-based near-real time Multi-satellite Precipitation Analysis (TMPA).

The TMPA precipitation data covered the period from April 1 to 14, 2014 which starts when Ita formed in the Coral Sea and moved along northeastern Australia's coast.

This TRMM satellite rainfall map estimated that some of the largest isolated rainfall totals were near 400 mm/15.7 inches west of both Ingham and Townsville, Queensland.

A 3-D image of Ita was made at NASA using data collected by the TRMM satellite on April 14, 2014 at 0416 UTC/12:16 a.m. EDT after the tropical storm moved back into the Coral Sea.

TRMM's Precipitation Radar (PR) instrument found that the weakening tropical cyclone was still dropping rainfall at a maximum rate of over 161 mm/6.3 inches per hour over the Coral Sea.

The 3-D image, created using TRMM PR data, showed that some storms within Ita were still reaching heights of over 13 km/8 miles as it was becoming extra-tropical.

NOAA's Suomi NPP satellite

Another NASA-shared satellite captured a visible look at Ita's remnants on April 15. The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard NASA-NOAA's Suomi NPP satellite captured a look at the dying extra-tropical storm.

VIIRS collects visible and infrared imagery and global observations of land, atmosphere, cryosphere and oceans.

This 3-D image shows the structure of Tropical Cyclone Ita on April 14 at 0416 UTC/12:16 a.m. EDT. 

Some storms within Ita were still reaching heights of over 13 km/8 miles. 

Credit: SSAI/NASA/JAXA, Hal Pierce

When Suomi flew over Extra-Tropical Storm Ita on April 15 at 3:53 UTC/April 14 at 11:53 p.m. EDT, VIIRS visible data revealed that Ita's structure had elongated more than the previous day.

The VIIRS image showed that strong northwesterly wind shear continued to hammer the storm because the bulk of the storm's clouds were pushed southeast of the center.

Tropical Cyclone Ita's remnants have taken on more of a frontal appearance today as they continue to weaken at sea.

This visible image of an elongated Tropical Cyclone Ita was taken from the VIIRS instrument aboard NOAA's Suomi NPP satellite on April 15 at 3:53 UTC and shows that wind shear has blown most clouds and thunderstorms south of the center. 

Credit: NRL/NASA/NOAA