Dusty Mars

These side-by-side movies show how dust has engulfed Mars. They’re derived from data taken by the Mars Color Imager onboard the Mars Reconnaissance Orbiter. The view from May shows Valles Marineris chasms (left), Meridiani center, an autumn dust storm in Acidalia (top) and the early spring south polar cap (bottom). The view from July shows the same regions hidden by the dust cloud and haze that covered the planet.

Video Credit: NASA

You Are Here

earth-from-mars-hiresThe most powerful telescope orbiting Mars took this view of Earth and its Moon, showing continent-size detail on the planet. The image combines two separate exposures taken last November by the High Resolution Imaging Science Experiment (HiRISE) camera on the Mars Reconnaissance Orbiter. The images were taken to calibrate HiRISE  using the known value of reflectance for the Earth-facing side of the Moon. The exposures used to make this composite image were processed separately to optimize detail visible on both Earth and the Moon. The Moon is much darker than Earth and would barely be visible if shown at the same brightness scale as Earth.

The combined view retains the correct positions and sizes of the two bodies relative to each other. The distance between Earth and the Moon is about 30 times the diameter of Earth. Earth and the moon appear closer than they actually are in this image because the observation was planned for a time at which the Moon was almost directly behind Earth as seen from Mars so that the Earth-facing side of the Moon would be visible.

The reddish feature near the middle of the face of Earth is Australia. Mars was about (205 million km from Earth when the images were taken.

Image Credit: NASA

Comet Siding Spring

Siding Spring MROThese images were taken of Comet C/2013 A1 Siding Spring by the Mars Reconnaissance Orbiter on 19 October during the comet’s close flyby of Mars. The comet is on its first trip this close to the sun from the Oort Cloud at the outer fringe of the Solar System. These are the first resolved images of the nucleus of a long-period comet.

The images of the comet were acquired at a range of about 138,000 kilometers. The scale is roughly 138 meters per pixel. Telescopic observations had suggested that the size of the nucleus was about 1 km wide. However, the best Mars Reconnaissance Orbiter images are two to three pixels across the brightest feature, suggesting that the size of the nucleus is less than half the earlier estimate.

This composite image shows two versions of two of the best images take by the HiRISE camera on the Mars Reconnaissance Orbiter. At the top are images with the full dynamic range, showing the nucleus and bright coma near the nucleus. At the bottom are versions where the fainter outer coma is brightened, saturating the inner region. The left and right images were taken about nine minutes apart.

Image Credit: NASA

Mars Orbiter and Comet Siding Spring

This afternoon, Comet C/2013 A1 (AKA Comet Siding Spring) will pass within about 140,000 km of Mars. That’s less than half the distance between Earth and the Moon and less than one-tenth the distance of any known comet flyby of Earth. Siding Spring’s nucleus will come closest to Mars around 18:27 UTC (2:27 pm ET) moving at around 56 km/s.

Video Credit: NASA

A Near Miss at Mars

Near MissThis graphic shows the predicted orbit of comet C/2013 A1 Siding Spring as it swings around the inner Solar System in 2014. On 19 October, the comet will pass very close to Mars. Its nucleus will miss Mars by about 132,000 km. As it flies by it, will be shedding material moving at over 50 km/s, relative to Mars and Mars-orbiting spacecraft. Even a tiny particle only 0.5 mm across moving at that speed could cause significant damage to a spacecraft.

NASA currently operates two Mars orbiters, and a third on its way, arriving in Martian orbit a month before the comet flyby. Teams operating those orbiters plan to adjust their orbits so that the spacecraft will be on the opposite side of the Mars when the comet is most likely to pass by.

Image Credit: NASA

The Sand Dunes of Mars

Martian Spring DunesThis picture was taken by the HiRISE camera on the Mars Reconnaissance Orbiter last January. It shows Mars’s northern-most sand dunes beginning to emerge from their winter cover of seasonal dry ice (frozen CO2). The dark, bare south-facing slopes are soaking up the warmth of the sun. The steep downwind sides of the dunes are also ice-free along the crest, allowing sand to slide down the dune. The dark areas are places where ice cracked earlier in the spring, releasing sand. Eventually, the dunes will be completely bare and all signs of spring activity will be gone.

Image Credit: NASA

Curiosity From Space

curiosityfromspaceThe Mars rover Curiosity appears as a bluish dot at the right end of a thin, wiggly line of tracks in this enhanced-color view from the High Resolution Imaging Science Experiment (HiRISE) camera on the Mars Reconnaissance Orbiter. The camera took this picture on 27 June, 2013.

The two scour marks at the Bradbury Landing site where the Mars Science Laboratory mission’s skycrane landing system landed Curiosity on 6 August, 2012, are on the far left. Dark scour marks show where the landing system’s rockets swept away reddish surface dust. Visible tracks lead from the landing site toward the rover.

Image Credit: NASA

A Crater on Phobos

Stickney900Stickney Crater, the largest crater on the Mars’ moon Phobos, is named for Chloe Angeline Stickney Hall, mathematician and wife of astronomer Asaph Hall who discovered both the planet’s moons in 1877. At a bit more than 9 km across, Stickney is nearly half the diameter of Phobos itself. It’s so large that the impact that blasted out the crater nearly shattered the tiny moon. This enhanced-color image of Stickney was recorded by the HiRISE camera onboard the Mars Reconnaissance Orbiter at a range of about 6,000 km. Even though the moon’s gravity is less than 0.1 percent of Earth’s, streaks suggest loose material has been sliding down inside the crater walls over time.

Image Credit: NASA


This moon is doomed. In 100 million years or so Phobos will likely be shattered by stress caused by relentless tidal forces, its debris forming a decaying ring around Mars. Mars has two small moons, Phobos and Deimos. Their names are derived from the Greek for Fear and Panic. The larger moon Phobos is a cratered, asteroid-like object in this image taken by the Mars Reconnaissance Orbiter. Click to embiggen the image to 7 m per pixel resolution.

Image Credit: NASA

Curiosity As Seen From Orbit

The Mars Reconnaissance Orbiter’s HIRES camera has snapped this picture of the Curiosity rover. The image has been color enhanced so that features near the rover stand out. The descent stage blast pattern around the rover shows up as the bluish area (true colors would be more gray). The rover is the dot inside the blue smudge.

Image Credit: NASA