When NASA sent Mars Reconnaissance Orbiter (MRO) to the red planet in 2006, the spacecraft took with it an instrument called CRISM – Compact Reconnaissance Imaging Spectrometer for Mars. CRISM’s job is to produce maps of the surface mineralogy of Mars. This is a huge success, but unfortunately the loss of its last cryocooler in 2017 means the spectrometer can only undertake limited observations.
But CRISM storms out, creating one last image of the surface of Mars that NASA will release in batches over the next six months.
What’s new – The new map will cover 86% of the surface of Mars. It will be 5.6 gigapixels in size and will reveal the locations of dozens of important minerals in 72 colors. Since many minerals form in the presence of water, the locations of certain minerals reveal evidence of Mars’ aquatic past. The new map will also help plan future missions and choose the most promising places for rovers to visit.
We already have the first portions of the new menu. The final version of the map will contain approximately 51,000 strips 540 kilometers long, contained in 1764 tiles. As of mid-June, NASA released 48 of these tiles, and they cover five of the most scientifically interesting regions on Mars.
The final map is an all-new dataset and the first of its kind. The data was collected over the years of the mission but was never put together, although the mission scientists had this project in mind.
“This is actually a whole new set of data that will fuel a second wave of discoveries about the composition of the surface of Mars.”
“We’ve had map tiles as a product defined in the books since the very beginning,” said Frank Seelos, PLA planetary scientist and CRISM mapping project manager.
“We knew we wanted to do this, but it took us many, many years to get to the point where we had enough data and the tools to make it worthwhile.”
How they did — CRISM has made around 33,000 high-resolution images over the years, and they have helped identify landing sites for rover missions, and also informed the future Mars Sample Return mission.
But while he was doing this work, he was also gathering lower resolution map strips, about 83,000 of them. Now that CRISM is no longer active, the team builds its map from these tapes.
Processing so much data into a single coherent map is a complicated task requiring powerful computing resources. It takes time to optimize the maps and take into account the environmental conditions and the differences between the different images.
“For an individual tile, the optimization process can take just five hours in some exceptional cases, but sometimes it will take more than a day,” said Katie Hancock, CRISM team member, software developer at APL who led the development of the optimization code. In a JH/UAPL press release, Hancock said it would take a computer cluster a month to build the map of the entire planet.
Why is it important – The map will be important for years to come and will fuel future Mars discoveries.
“This is actually a whole new set of data that will fuel a second wave of discoveries about the composition of the surface of Mars,” said Scott Murchie, planetary scientist at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, and principal investigator of CRISM.
“In fact, one of the goals of the next extended MRO mission is for its HiRISE camera to go back and color image the hundreds of new high-science hotspots we find on the map – spots that haven’t were imaged at high resolution because their significance was not known.
Take pictures of Mars
CRISM is still operational in a limited way. Without a cryocooler, it will not be able to perform infrared observations and will be limited to visible light operations. It is in standby mode at the moment and is on deck until it is decommissioned in a few months.
The Mars Reconnaissance Orbiter is still performing well and has exceeded its planned mission by several years. In 2018, NASA said it wanted the spacecraft to continue operating until at least the late 2020s. One of the obstacles to greater longevity is its aging gyroscopes, but NASA said it can rely on stellar navigation to maintain the spacecraft’s orientation.
MRO’s HiRISE camera captured nearly 70,000 high-resolution images of the surface of Mars. It doesn’t rely on a cryocooler, so as long as the MRO is running, we’ll still see great visible-light images of Mars.
ESA’s Mars Express Orbiter is also still operating on Mars, and it carries its own spectrometer. The Infrared Mineralogical Mapping Spectrometer, or Observatory for Mineralogy, Water, Ice and Activity (OMEGA) also uses near infrared to map mineral concentrations on the Martian surface.
And after – Frank Seelos, head of the CRISM mapping project, points out that the mission was a success and that the instrument does not need to contribute more than it already has to be a large part of the exploration of Mars.
“The warranty on this thing expired years ago before my kids were even born,” Seelos said. “CRISM’s investigation has taken a very long time, and the fact that we have been able to collect data for so many years is incredible. The release of these tiles is something of an exclamation point for the legacy of the instrument. .
“The CRISM survey was one of the crown jewels of NASA’s MRO mission,” said Richard Zurek, mission project scientist at NASA’s Jet Propulsion Laboratory in Southern California. “Analysis based on these final maps will provide new information about the history of Mars for many years to come.”
If you want to dig deeper into what CRISM is showing us about minerals on the surface of Mars, visit JHUAPL’s MICA site. MICA is a downloadable set of published descriptions and typical locations of unique spectral features identified on Mars using CRISM data. It was released in 2019.
This article was originally published on Universe today by Evan Gough. Read the original article here.