Communications

The Mars 2020 rover, Perseverance, has three antennas that serve as both its "voice" and its "ears." They are located on the rover equipment deck (its "back"). Having multiple antennas provides operational flexibility and back-up options just in case they are needed. Antennas on rover deck:

Ultra-High Frequency Antenna

Most often, Mars 2020 uses its ultra-high frequency (UHF) antenna (about 400 megahertz) to communicate with Earth through NASA's orbiters around Mars. Because the rover and orbiter antennas are within close range of each other, they act a little like walkie-talkies compared to the long-range telecommunications with Earth provided by the low-gain and high-gain antennas. It generally takes about 5 to 20 minutes for a radio signal to travel the distance between Mars and Earth, depending on planet positions. Using orbiters to relay messages is beneficial because they are much closer to Perseverance than the Deep Space Network (DSN) antennas on Earth. The mass- and power-constrained rover can achieve high data rates of up to 2 megabits per second on the relatively short-distance relay link to the orbiters overhead. The orbiters then use their much larger antennas and transmitters to relay that data on the long-distance link back to Earth.

Tech Specs

  • Main Job Transmitting Data to Earth through Mars Orbiters
  • Radio Frequency Ultra-High Frequency (UHF) band (about 400 megahertz)
  • Transmission Rates Up to 2 megabits per second on the rover-to-orbiter relay link.

The X-Band High-Gain Antenna

The high-gain antenna is steerable so it can point its radio beam in a specific direction. The benefit of having a steerable antenna is that the entire rover doesn't need to change position to talk to Earth, which is always moving in the Martian sky. Like turning your neck to talk to someone beside you rather than turning your entire body, the rover can save energy and keep things simple by moving only the antenna. Its high gain allows it to focus its beam, allowing higher data rates on the long link back to Earth.

Tech Specs

  • Main Job Transmitting data directly to and from Earth
  • Radio Frequency X band (7 to 8 gigahertz)
  • Location Mounted mid-aft portside of Mars 2020 deck ("back")
  • Size Hexagonally shaped, 1 foot (0.3 meters) in diameter
  • Transmission/ Reception Rates 160/500 bits per second or faster to/from the Deep Space Network's 112-foot-diameter (34-meter-diameter) antennas or at 800/3000 bits per second or faster to/from the Deep Space Network's 230-foot-diameter (70 meter-diameter)
  • Provided by Spain

The X-Band Low-Gain Antenna

Mars 2020 uses its low-gain antenna primarily for receiving signals. This antenna can send and receive information in every direction; that is, it is "omni-directional." The antenna transmits at low data rate to the Deep Space Network antennas on Earth. Because it doesn’t need to be pointed, it provides a robust way to always communicate with the rover.

Tech Specs

  • Main Job Receiving Data
  • Radio Frequency X band (7 to 8 gigahertz)
  • Reception Rates Approximately 10 bits per second or faster from the Deep Space Network's 112-foot-diameter (34-meter-diameter) antennas or approximately 30 bits per second or faster from the Deep Space Network's 230-foot-diameter (70-meter-diameter) antenna