In order to contact its interplanetary spacecraft, NASA relies on an array of giant radio antennas spread across different parts of the world. The trusty communications network has been transferring data back and forth for more than 60 years but its antennas are currently operating at capacity, with an anticipated growth in demand as the space agency prepares to launch crewed missions to the Moon.
A recent report by NASA’s Office of Inspector General revealed that the Deep Space Network (DSN) is in a dire state, with demand on its radio antennas exceeding supply by as much as 40% at times. This means that ongoing space missions are requesting more time than the network’s current capacity can provide. In the past five years, NASA missions received between 8,500 and 15,000 less DSN tracking hours than requested, according to the report.
The report also anticipated that demand for DSN support “will increase dramatically in the coming decade with excess demand for hours on the DSN reaching about 50 percent by the 2030s.” A major part of that increased strain on the network will be NASA’s upcoming Artemis missions to the Moon, with the first crewed mission scheduled to launch in late 2024.
“When Artemis comes online, everybody else moves out of the way, and it’s an impact to all the science missions,” Suzanne Dodd, director of the interplanetary network directorate at NASA’s Jet Propulsion Laboratory, is quoted in SpaceNews as saying during a meeting of the NASA Advisory Council’s science committee on Tuesday.
With the launch of Artemis 1 in November 2022, the Orion spacecraft used up 903 hours of DSN time while the mission’s secondary payloads (eight cubesats) took up an additional 871 hours, according to SpaceNews. “I’m not sure who thought it was a good idea” to put those cubesats on Artemis 1, Dodd is quoted as saying. “I don’t think that’s a good use when your DSN is oversubscribed.”
Mission teams use DSN’s scheduling system to request network capacity to communicate with their spacecraft. “As capacity challenges grow and issues such as unforeseen outages occur, missions’ have expressed frustration with the process for scheduling and rescheduling DSN support,” the report read.
DSN uses radio frequency transmissions that travel through large antenna systems. The network is made up of three deep-space communications facilities located at Goldstone in California’s Mojave Desert, another near Madrid, Spain, and the third near Canberra, Australia. The locations are strategically placed approximately 120 degrees apart to ensure that at any point in time, one or more of these facilities can communicate with a spacecraft as the Earth rotates around its 360 degree axis.
In order to relieve some of the increasing demand on the network, NASA’s Office of Inspector General recommended that the space agency build new antennas and upgrade its existing infrastructure. NASA has been making efforts to upgrade DSN in order to meet new mission needs, including the installation of 18-meter antennas called LEGS dedicated to lunar missions, but its efforts have fallen behind on schedule and ran over budget. The space agency is currently looking into other options such as turning to foreign partners or utilizing commercial communication systems.
“As NASA pivots toward extended human exploration of the Moon, the agency may need to give DSN capacity to priority missions in critical phases, such as launches, while other missions make do with limited or no data during those periods,” the report stated.