One More Item Found in Astounding HiRise Image of Phoenix Descending

By Nancy Atkinson - July 9, 2008 at 4:35 PM UTC | Planetary Science
hirise-extra-findbig.jpg

Remember the

amazing image

that the HiRISE Camera on the Mars Reconnaissance Orbiter captured of the Phoenix Lander as it descended to Mars' surface via parachute back on May 25? Well, the HiRISE scientists have done a little more processing of the image, and have turned up an additional detail they didn't see at first: Phoenix's heat shield. The heat shield, which had been jettisons just after parachute deployment, can be seen falling toward the surface. You have to look

really, really

close to see it. But that's what these HiRISE folks do. It was incredible that they found the lander with the parachute in the image (go see the big, huge image they had to hunt for it

HERE

) and these guys get the eagle eyes of the year award for finding the heat shield.

HiRISE made history by taking the first image of a spacecraft as it descended toward the surface of another planetary body. Here's the image again:

The image shows NASA's Phoenix Mars Lander when the spacecraft was still tucked inside its aeroshell, suspended from its parachute, at 4:36 p.m. Pacific Daylight Time on landing day. Although Phoenix appears to be descending into an impressive impact crater, it actually landed 20 kilometers, or 12 miles, away.

Mars Reconnaissance Orbiter was about 760 kilometers, or 475 miles, away when it pointed the HiRISE camera obliquely toward the descending Phoenix lander. The camera viewed through the hazy Martian atmosphere at an angle 26 degrees above the horizon when it took the image. The 10-meter, or 30-foot, wide parachute was fully inflated. Even the lines connecting the parachute and aeroshell are visible, appearing bright against the darker, but fully illuminated Martian surface.

In further analyzing the image, the HiRISE team discovered a small, dark dot located below the lander. Phoenix was equipped with a heat shield that protected the lander from burning up when it entered Mars' atmosphere and quickly decelerated because of friction. Phoenix discarded its heat shield after it deployed its parachute.

"Given the timing of the image and of the release of the heat shield, as well as the size and the darkness of the spot compared to any other dark spot in the vicinity, we conclude that HiRISE also captured Phoenix's heat shield in freefall," said HiRISE principal investigator Alfred McEwen.

The multigigabyte HiRISE image also includes a portion recorded by red, blue-green and infrared detectors, and scientists have processed that color part of the image.

HiRISE's color bands missed the Phoenix spacecraft but do show frost or ice in the bowl of the relatively recent, 10-kilometer (6-mile) wide impact crater unofficially called "Heimdall." The frost shows up as blue in the false-color HiRISE data, and is visible on the right wall within the crater.

The HiRISE camera doesn't distinguish between carbon dioxide frost and water frost, but another instrument called CRISM on the Mars Reconnaissance Orbiter could.

News Source: SpaceRef

Nancy Atkinson

Nancy Atkinson

Nancy Atkinson is a space journalist and author with a passion for telling the stories of people involved in space exploration and astronomy. She is currently retired from daily writing, but worked at Universe Today for 20 years as a writer and editor. She also contributed articles to The Planetary Society, Ad Astra (National Space Society), New Scientist and many other online outlets.

Her 2019 book, "Eight Years to the Moon: The History of the Apollo Missions,” shares the untold stories of engineers and scientists who worked behind the scenes to make the Apollo program so successful, despite the daunting odds against it. Her first book “Incredible Stories From Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos” (2016) tells the stories of 37 scientists and engineers that work on several current NASA robotic missions to explore the solar system and beyond.

Nancy is also a NASA/JPL Solar System Ambassador, and through this program, she has the opportunity to share her passion of space and astronomy with children and adults through presentations and programs. Nancy's personal website is nancyatkinson.com