Sunday Read: The Cameras of Curiosity

Sunday Reads

Alex Parker 
12th February 2023

Just keep swimming...

At time of writing, NASA’s Curiosity Rover has been exploring the surface of Mars for 3841 days – over 10 years. This is an incredible achievement when you consider the difficulties in even getting the Rover there, followed by a decade where adverse weather or a single moment of dodgy navigation could spell instant curtains.

Initially, NASA was hopeful that Curiosity would roam and transmit data for two years on its mission to find out whether Mars ever supported life, with every system engineered with redundancies for redundancies should anything fail in the harsh conditions. Thanks to the incredible work of the team in the years leading up to the launch from Cape Canaveral in 2012, it’s very much still all systems go.

 

I'm something of a photographer, don't you know

As impressive as the technical achievements of continued operation are, the most exciting result is the photos. Curiosity is equipped with an arsenal of cameras, designed for navigation, measuring various spectrums for scientific study, and general observation. The steady stream of jaw-dropping images the rover has transmitted home during its overwhelmingly successful mission is well worth an explore.

Feb 2023

Curiosity has 17 cameras in total, utilising Kodak's smallest CCD chips available at time of spec. All cameras have a set purpose but can also double as general point-and-shoots, though none of them are higher than 2 megapixels:

8 Hazcams (hazard avoidance cameras)
4 Navcams (pairs of cameras designed for navigation)
2 Mastcams designed for scientific study
1 Chemcam, designed to fire a laser and analyse the ground
1 MAHLI cam (Mars Hand Lens Imager) designed like a macro for close ups
1 MARDI cam (Mars Descent Imager) designed to help the rover land

Taken by Curiosity's Navcams and colourised in post, Nov 2021

The man behind the curtain

The bulk of the most spectacular landscape photos were taken by the Mastcams, with detailed surface shots stitched together from multiple images taken by the MAHLI. In 2012 prior to launch, chief camera designer Mike Ravine explained that the specs for the camera were initially decided upon as far back as 2004, when the 2-megapixel camera was a little less underpowered.

'There's a popular belief that projects like this are going to be very advanced but there are things that mitigate against that. These designs were proposed in 2004, and you don't get to propose one specification and then go off and develop something else. 2MP with 8GB of flash memory didn't sound too bad in 2004. But it doesn't compare well to what you get in an iPhone today.'

With the plan always being to stitch multiple images together anyway, Ravine felt that a higher resolution camera wouldn’t have necessarily achieved better results in the multi-shot panoramic way the cameras are used.

'We also looked at a 4MP sensor, but it would have run around half as fast. And the state of CMOS sensors wasn't credible in 2004. They're an interesting option now, but they weren't then. A mosaic produced from a higher pixel count camera wouldn't offer huge benefits over what we'll be getting.'

Echoes of the past

With clear evidence of water and minerals on and below Mars’ surface, Curiosity has taken photos of many dead rivers and lakes, mountain ranges and deserts, all proving that the planet once could have supported life, even if that life was microscopic.

Even the Rover’s landing point produced eye-opening study opportunities for scientists. The Gale Crater is a huge impact crater estimated to be over 3.5 billion years old, which over millennia has accumulated layers of rock and mud, layer upon layer piling high. In driving up these rock and mud layers, Curiosity was treated to a potted history of the planet for scientists to analyse.

 

Next gen

With the tremendous success of the Curiosity mission, NASA engineered a new rover, Perseverance, which launched in 2020 and landed succesfully in 2021. Featuring 23 separate cameras up to 20-megapixels, the new rover packs quite a punch compared to the previous mission.

Feb 2021

All well and good, but it hasn’t cramped Curiosity’s style – only this week the plucky rover was sending pictures back to earth of new discoveries, this time a sizeable lump of metal. Curiosity will eventually succumb to its harsh new home, but its mission was a resounding success long ago, and there is a case to suggest its staying power marks one of NASA’s greatest ever achievements.

 

All images featured in this article belong to NASA/JPL-Caltech

Head to the link to see the full gallery of shots Curiosity has beamed home https://mars.nasa.gov/msl/multimedia/images/