In a first, viewers on Earth got a chance to see Mars nearly in real time.
The European Space Agency streamed on YouTube historic live images directly from the red planet.
The images, shared on YouTube, ESA’s Twitter account and with the hashtag #MarsLIVE, showed the planet in a way it has never been seen before, ESA said.
The event celebrated the 20th anniversary of the launch of the agency’s Mars Express orbiter — a mission to take three-dimensional images of the planet’s surface to see it in more complete detail.
“Normally, we see images from Mars and know that they were taken days before,” said James Godfrey, spacecraft operations manager at ESA’s mission control center in Darmstadt, Germany, in a statement. “I’m excited to see Mars as it is now — as close to a martian ‘now’ as we can possibly get!”
But haven’t we seen images of Mars before? Yes, but not live, the ESA said.
Often data and observations of the red planet are taken when a spacecraft is not in direct contact with Earth, so the images are stored until they can be sent back, ESA said.
Depending on where Mars and Earth are in their orbits around the sun, the messages that journey through space can take anywhere from 3 to 22 minutes.
The ESA had estimated it would take about 17 minutes for the light needed to form the images to travel directly from Mars to Earth and then another minute to get through the wires and servers on the ground to get the live stream started, the agency said.
“Note, we’ve never tried anything like this before, so exact travel times for signals on the ground remain a little uncertain,” the agency said in a statement prior to the event.
No stars were visible in the background of the images because Mars is quite bright, noted Colin Wilson, a project scientist at ESA.
“If you’re very close to it, it is even brighter,” Wilson noted, and that obscures the surrounding stars in this particular angle the spacecraft is snapping images from.
But, if you were on the Mars Express spacecraft, you would be able to see much of the cosmos, Wilson added. “And that is in fact critical to how Mars Express navigates,” he said. The spacecraft uses an onboard map and its imaging of the stars to orient itself in space, much the way humans have navigated the oceans going back centuries.
Over the course of an hour, new views of Mars were expected about every 50 seconds, according to the statement from the agency prior to the event. However, for some time, the transmissions from Mars were interrupted, the ESA scientists noted, as a ground station near Madrid experienced bad weather.
Some viewers may also have noticed that the red planet did not appear as red as expected. Jorge Hernández Bernal, part of the Mars Express’s visual monitoring camera team, noted during the live stream that Mars was appearing as it would if you captured an image with an iPhone, not as it would be seen with the naked eye.
“Color is a very complex topic related to the way our eyes work,” he noted. And the spacecraft’s images also undergo some processing, to remove “noise” — or unwanted disturbances in the imagery — that can also alter their appearance.
About one hour’s worth of images were dispatched from Mars Express before the spacecraft moved too far from Mars to continue capturing the planet. Scientists noted that additional updates will be shared on Twitter.