Simulating Long-Distance Calls to Mars

MAVEN Undergoes Communications Tests

Last week while I was attending a meeting of planetarium folk in Kansas City, the MAVEN mission went through a series of communications tests at the Kennedy Space Center as engineers continue to prep the spacecraft for its trip to Mars. This is pretty crucial; you don’t want to get all the way to Mars only to find out something happened to the radio comm system. So, part of the launch prep is to test all the systems, including the communications packages.

MAVEN, which is the latest mission to Mars, is going to the Red Planet to study the upper atmosphere. The other missions we’re familiar with are on the ground (Curiosity, for example) or mapping the planet from orbit (Mars Reconnaissance Orbiter). This one is going to spend its time swooping through parts of the upper atmosphere and gather data about that thin, thin layer of Martian “air” that will tell scientists more about what’s there, how the atmosphere has evolved over time, and try to measure the loss of volatiles (gases) from the uppermost layers. The science mission for MAVEN (which stands for “Mars Atmosphere and Volatile Evolution”) is focused primarily on figuring out which processes allow the top of the atmosphere to escape to space. From that information, scientists will be able to get a better handle on the climate change Mars has undergone since its formation.

It’s pretty clear that Mars was once warmer and somewhat wetter than it is now, and atmospheric escape must have played a huge role in turning Mars into the desert it is today. So, MAVEN will be gathering a lot of data, and sending it back to Earth. That’s why it’s important to have a robust set of comm instruments onboard. During last week’s tests, engineers simulated the distance over which MAVEN’s signals must pass. They beamed test signals to the spacecraft’s low-gain and high-gain antennas and through that practice, treated the instruments as if they were on the 10-month journey to Mars and then on its orbital mission.

I found the procedure fascinating to read about, particularly how they simulated “real conditions”. First, the engineers rigged up a way to ramp down the power of the signals by sending them through a series of wiring networks. In essence, they found ways to reduce the signal down to the lowest possible power. Then, the instrument scientists logged into to the system and went through a normal day’s mission commands, as if they were talking to a spacecraft actually at Mars. It was a good practice for everybody, and just the latest in a series of simulations the teams are going through as the November launch date gets nearer.

In “real time”, the spacecraft will gather its data and then send it back to Earth via its onboard radio systems. The signals will be received by the Deep Space Network, and then sent along to the scientists at the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. From there, the team members in the U.S. and France will get and analyze their data, helping put t0gether a fuller, richer story about Mars and the role its atmosphere plays.