Sometimes, we take space technology for granted. As the deadly Hurricane Matthew made its destructive way through the Caribbean to South Carolina and the U.S. East Coast, we were able to watch its approach very carefully. Weather satellites tracked its movements minute by minute, while astronauts on the International Space Station took photographs as the orbiting outpost passed over the monstrous storm several times a day. This careful monitoring helped us understand the hurricane's impact and aided emergency services since predictions of the storm track allowed for evacuations ahead of time.
On Mars, however, we only have a handful of satellites orbiting the planet and only a few instruments dedicated to observing the atmosphere. So when humans land on the surface — which NASA hopes will happen in the 2030s and SpaceX even sooner — it will be more difficult to predict the weather around them unless more satellites and weather stations are deployed. But as the decades go on, more spacecraft are arriving at Mars and it's possible that we will see a network in place by the time humans walk on the surface.
Weather predictions on Mars currently come in weekly from researchers at San Diego's Malin Space Science Systems (MSSS), which manufactured many of the cameras on Martian rovers and orbiters for NASA. They use the Mars Color Imager camera on NASA's Mars Reconnaissance Orbiter to make the predictions. But to really have a robust weather forecast system, NASA planetary scientist Michael Smith says you will need a large network of orbiters and ground weather stations to see what's going on.
"In our business, the more, the better," said Smith, who works at the NASA Goddard Space Flight Center in Maryland. One aspect that is particularly difficult to measure is wind, he told Seeker, because a lidar (a detection system that uses lasers, following the same principles as radar) is required from orbit to track speeds of dust or changes in the atmosphere. Also, ground stations are helpful to feed individual location measurements into the models.
But improvements are coming. NASA's Jet Propulsion Laboratory recently announced the next global dust storm on Mars will likely take place on Oct. 29. It's the first time that such a precise prediction has been available, and it's based on observations of past planet-shrouding storms since 1924. Researchers have detected nine storms in that time, with the most recent five being in the space age when we've had orbiters at Mars: 1977, 1982, 1994, 2001 and 2007.
"The actual number of such events is no doubt higher," NASA said in a statement. "In some of the years when no orbiter was observing Mars up close, Mars was poorly positioned for Earth-based telescopic detection of dust storms during the Martian season when global storms are most likely."
JPL planetary scientist James Shirley detected a pattern in dust storms, which was published in the journal Icarus last year. His team found that global dust storms are more likely to occur when the motion of other planets affects Mars' momentum in its orbit during the first part of the dust storm season. But more data is always useful to refine the prediction.
There have been a handful of weather stations on the surface of Mars. NASA's Curiosity rover, which has been there since 2012, carries a Rover Environmental Monitoring Station that can send daily and seasonal reports back to Earth. Some of the things that it measures include "atmospheric pressure, humidity, ultraviolet radiation at the Martian surface, wind speed and direction, air temperature, and ground temperature," NASA said on its Curiosity website.
Although weather on Mars is less dramatic as the hurricanes and storms we track on Earth, global dust storms will be a hazard for future Mars explorers, especially if solar-powered equipment is used. Missions such as NASA's Mars Exploration Rovers (particularly Opportunity, pictured above), have been impacted by solar array-clogging dust in the thin Martian atmosphere, reducing the amount of sunlight that can be converted to electricity. At best, this would be a frustrating maintenance issue, at worst, it could starve future habitats of energy should most of their power be drawn from solar resources. Dust storms are also known to generate electrical charge in the atmosphere, potentially disrupting sensitive computers on the surface.
Besides helping with keeping astronauts safe, such weather predictions can also help us learn about the Martian environment generally. For example, in 2015, Curiosity's measurements let NASA announce that conditions at Gale Crater are favorable to form brine, or salty water, in the soil during night.
NASA's Phoenix mission (which also carried a weather station) identified the toxic chemical perchlorate in the Martian soil in 2008. Perchlorate, NASA said in a 2015 press release, "has properties of absorbing water vapor from the atmosphere and lowering the freezing temperature of water. This has been proposed for years as a mechanism for possible existence of transient liquid brines at higher latitudes on modern Mars, despite the Red Planet's cold and dry conditions."
It's a big improvement over a couple of decades ago, but Smith said he is eager for more data. If he could build a system without worrying about the budget, he said he would like to see more observations from orbiters and landers, to improve our understanding of the underlying physical processes that drive Martian weather. He adds that as NASA prepares for Mars landings in the 2030s, he expects that computer models would be even more detailed than what we have today, which could help improve predictions.
While the 2030s seem like a long way from now, space missions often take at least a decade to plan. So the future of weather prediction will depend on what orbiters and landers are in the works in the coming years. It's possible, Smith added, that NASA's push to bring CubeSats to Mars could allow these small spacecraft to eventually serve as remote weather stations, since most of the instruments (except the lidar) could be accomplished with simple electronics. This could allow for expanded weather monitoring operations at a relatively low cost.
Originally published on Discovery News.