Deep space dial-up: How NASA speeds up its interplanetary communications

On November 26, 2018 at 2:52:59 ET, NASA did it again—the agency’s InSight probe successfully landed on Mars after an entry, descent, and landing maneuver later dubbed "six and a half minutes of terror.” The moniker fits because NASA engineers couldn't know right away whether the spacecraft had made it safely down to the surface because of the current time delay (roughly 8.1 minutes) for communications between Earth and Mars. During that window of time, InSight couldn't rely on its more modern, high-powered antennas—instead, everything depended on old-fashioned UHF communications (the same method long utilized in everything from TV antennas and walkie-talkies to Bluetooth devices).Eventually, critical data concerning InSight's condition was transmitted in 401.586Mhz radio waves to two CubeSats called WALL-E and EVE, which in turn relayed the data at 8Kbps back to huge 70 meter antennas on Earth. "These can look down at low-Earth orbiters and communicate with them, and this information then gets relayed from the TDRS satellites to the ground,” Abraham explains. “That's the trafficking and data relay satellite system generally known as NASA's Space Network.”But even the TDRS was not enough to communicate with spacecraft flying way beyond the Moon to other planets. Only 70-meter antennas can get through to them and get their data back to Earth,” Abraham explains.The 70-meter dishes are also used when a spacecraft can't communicate with its high-gain antenna, either because of a planned critical event like an orbit insertion or because something has just gone terribly wrong.