WASHINGTON — Increasing demand but decreasing budgets are putting a strain on NASA’s Deep Space Network (DSN), threatening its ability to supply communications for the agency’s science missions and Artemis lunar expeditions.
While pressures on the DSN, a system of antennas positioned in Australia, California and Spain used primarily for communications with spacecraft beyond Earth orbit, have been growing for years, the Artemis 1 mission and the demands it placed on the network laid bare the challenges NASA will face in the long run, officials warned.
“When Artemis comes online, everybody else moves out of the best way, and it’s an impact to all of the science missions,” said Suzanne Dodd, director of the interplanetary network directorate at NASA’s Jet Propulsion Laboratory, during an Aug. 29 meeting of the NASA Advisory Council’s science committee.
Within the case of last fall’s Artemis 1 mission, the Orion spacecraft itself took 903 hours of DSN time, while eight cubesats launches as secondary payloads took an extra 871 hours. Science missions that use the DSN lost 1,585 hours in the identical period, including the James Webb Space Telescope, which lost 185 hours alone. NASA also deferred maintenance on the DSN during Artemis 1 to unencumber an extra 509 hours.
Accommodating Artemis missions also involves scheduling challenges as date shift, something the DSN needed to take care of on Artemis 1 due to its delays. “We either must clear everybody off the network for that launch window or we struggle — and our experience with Artemis 1 was combating attempting to move everybody around and shift it for the Artemis 1 launch date.”
The period of time utilized by the DSN on the cubesats took members of the science committee by surprise, and was a source of frustration for Dodd. “I’m unsure who thought it was an excellent idea” to place those cubesats on Artemis 1, she said. “I don’t think that’s an excellent use when your DSN is oversubscribed.”
Much of the DSN time used for the cubesats was on what she called “search and rescue” operations after they bumped into problems. She suggested NASA refrain from such efforts if future Artemis missions carry cubesats.
“We probably spent a whole lot of time on the lookout for these cubesats and things that didn’t work that, in the long run, I might recommend that we don’t do,” she said. “If we don’t hear your signal, your mission’s over.”
Demand grows and budgets decline
The DSN will proceed to see spikes in demand from future Artemis missions in addition to overall growth from an increasing variety of other missions, lots of that are business or government robotic lunar missions. “We’re nearly doubling the load on the DSN,” Dodd said. “The load is increasing and it’s very stressful to us.”
That’s compounded, Dodd said, by decreased budgets to operate the DSN. Its annual budget has fallen from $250 million in 2010 to $200 million today, with the budget projected to proceed to diminish through the tip of the last decade. “Searching to the 2030s, that actually scares us on the DSN.”
There have been several past reports which have warned of strains on the DSN. That included an audit of the DSN published July 12 by NASA’s Office of Inspector General. That report concluded that the network “is currently oversubscribed and can proceed to be overburdened by the demands created by an increasing variety of deep space missions,” and that efforts to reinforce the DSN with recent antennas is behind schedule and over budget.
“These are all great and, I might say, very accurate lessons learned,” Dodd said of that report and others. “There’s no money coming to overturn those challenges.”
She cited for instance an incident through the Artemis 1 mission when a system called a personal cloud appliance failed at a DSN site in Goldstone, California, causing a 33-hour outage. The network developed an answer that she said was not “excessive” to forestall it from happening again. “We got no funding for that.”
NASA is taking steps to deal with the demand on the DSN from Artemis missions, said Philip Baldwin, acting director of the network services division of NASA’s Space Communications and Navigation program. He outlined on the meeting a four-point plan that features upgrades of DSN antennas, installation of latest set of 18-meter antennas called LEGS dedicated to lunar exploration services, development of lunar communications and navigation relay services across the moon and increased international partnerships.
Nonetheless, he acknowledged that those steps alone, just like the six-antenna LEGS network, won’t solve all of DSN’s problems. “We’re talking about six antennas where now we have a deficit of greater than that.”
Studies help NASA discover gaps within the DSN, Baldwin said, but officials have to fastidiously articulate what they need given constrained budgets. “We are able to’t overreach here. We are able to’t just say, let’s double the DSN budget,” he said, noting that NASA was not expecting additional funding for DSN due to a debt-ceiling agreement enacted in June that keeps non-defense discretionary spending, which incorporates NASA, at 2023 levels for fiscal 12 months 2024.
“We’ve reached a extremely critical point with the DSN’s aging infrastructure,” said Sandra Cauffman, deputy director of NASA’s astrophysics division, who has been involved in studies of the network, noting that challenges will proceed even with upgrades like LEGS. “This scares us very much.”
It also scared members of the science committee. “We’ve clearly gotten a five-alarm fire bell,” said one committee member, Marc Weiser of RPM Ventures.
The DSN “is in a deep deficit, and I believe the one way we’re going to get out of it’s to spend the crucial resources not only to get better capability but to extend capability,” said Vint Cerf of Google, one other committee member.
Members of the committee spent a part of the meeting proposing recommendations to NASA to deal with the DSN’s problems, and thought of elevating the issue to the National Space Council. Nonetheless, Ellen Williams, chair of the science committee, noted that any recommendations couldn’t be formally transmitted to NASA until they were approved by the total NASA Advisory Council, which shouldn’t be expected to satisfy before November.