The Problem With NASA’s Deep Space Network
NASA’s Deep Space Network is one of the most important pieces of infrastructure the agency has access to. This group of radio antennas around the world is responsible for the communication and navigation support for nearly 60 NASA and international space missions. This includes the Mars Rover, James Webb Space Telescope, Voyager spacecraft, and many others.
Unfortunately, this system is only capable of so much, and the number of deep space missions has been increasing rapidly. This has put more pressure on the system than ever before and it will only get worse unless the agency steps in. A recent investigation by the NASA Office of Inspector General revealed the extent to which this system is being overworked.
NASA relies on its Deep Space Network (DSN) to provide communication links that guide and control spacecraft and bring back images and other data from missions. Without it, a lot of multi-million and billion-dollar space projects would simply become floating pieces of metal. Here I will go more in-depth into the current problem NASA is facing, possible solutions, the impact on upcoming missions, and more.
Overwhelmed
The DSN consists of three facilities spaced equidistant from each other – approximately 120 degrees apart in longitude – around the world. These sites include one in California, one in Spain; and one in Australia. The strategic placement of these sites permits constant communication with spacecraft as our planet rotates. Before a distant spacecraft sinks below the horizon at one DSN site, another site can pick up the signal and carry on communicating.
The DSN is managed by the Jet Propulsion Laboratory (JPL) and funded by NASA through a contract with the California Institute of Technology. NASA’s Office of JPL Management and Oversight oversees the contracts that NASA has with the Australian and Spanish governments to manage day-to-day operations at the foreign DSN sites. The DSN also provides radar and radio astronomy observations that improve our understanding of the solar system and the larger universe.
While obviously important, this system is facing a significant problem that needs to be solved soon. The NASA Office of Inspector General (OIG) conducts audits, reviews, and investigations of NASA programs and operations to prevent and detect fraud, waste, abuse, and mismanagement and to assist NASA management in promoting economy, efficiency, and effectiveness. Last month in July they released a report on the DSN network revealing pressing issues.
They were quoted saying, “NASA’s DSN is currently oversubscribed and will continue to be overburdened by the demands created by an increasing number of deep space missions, including crewed and robotic missions. Presently, the Agency’s DSN is responsible for communication and navigation support for nearly 60 NASA and international space missions. According to Agency internal capacity and loading studies, 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.”
They went on to say that “Limitations on the DSN’s capacity have already impacted Agency missions’ ability to fully meet objectives and achieve full return on investment. In the past 5 years, NASA missions have received between 8,500 and 15,000 fewer DSN tracking hours than requested. Going forward, the DSN will face an even greater strain when the network’s largest capacity users—the Mars Perseverance Rover, James Webb Space Telescope, and Artemis missions—will be in the same part of the sky vying for the same antennas. 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.”
Looking at a provided chart of deep space mission hour requirements, you can see how taxing big projects like the JWST can be, utilizing over 6,700 hours in 2022. It’s also important to point out that projects like these have a lifetime and need to be used while still in good condition. The agency can’t afford to simply stop communication with certain missions to focus on others without downsides.
In another quote they said, “According to the DSN capacity and loading studies, the estimate of needed DSN capacity will double when factoring in the Artemis missions. Over the next 10 years, the average data rate needed to be processed on the downlink (spacecraft sending images and data back to Earth) will be six times what it was in 2021 while the volume of data will increase by a factor of 37. The studies show that as the average data rates continue to increase, future unmet demand will result in very large data volume shortfalls on the DSN.” With the DSN already struggling to keep up with demand in 2023, the future will only add to this with somewhat exponential growth on deep space missions.
Possible Solutions
In reality, NASA was supposed to address this issue quite a long time ago, but hasn’t. In 2010, NASA initiated the Deep Space Network Aperture Enhancement Project (DAEP) to provide upgrades and capacity expansion to ensure continued operation and meet new mission needs. The DAEP planned to build six new antennas to replace existing antennas, equip each new antenna with a 20 kW transmitter, and add six additional high power 80 kW transmitters.
In regard to this, the most recent report was quoted saying, “However, the Agency’s efforts to complete the DAEP are behind schedule and over cost. As of the end of fiscal year 2022, NASA had only partially completed the first two phases of construction. Changes to the DAEP’s scope increased the expected costs from $419 million to $706 million, a 68 percent increase. Moreover, the Agency does not expect to have each of the three sites equipped with fully functional antennas until at least 2029, nearly 5 years behind schedule.”
As far as how this happened, NASA continues to face challenges while working under international agreements and contracts. According to NASA officials, the Agency has lacked insight into the selection of contractors and work performed at the sites in Australia and Spain, leading to issues with the quality and timing of work performed. In addition, NASA has yet to install 80 kW transmitters on antennas at the Australia and Spain sites and will need to obtain clearances from the Australian and Spanish governments prior to installation. These complications among other issues are what have held up this project and continued to add to its costs and timeline.
With this in mind, NASA needs to complete a few major projects and fast. NASA’s primary solution to address the DSN’s unmet demand is the additional antennas and upgrades ongoing and planned under the DAEP. However, as mentioned prior, this specific solution is already years behind and still won’t be enough by itself. According to internal studies, the Agency may need at least two more 34-meter antennas at each of the three sites to meet projected demand by the 2030s. Other options the Agency is exploring include the development of Lunar Exploration Ground Sites (LEGS), utilization of foreign partners and commercial providers communication assets, and equipping existing antennas to send and receive data across additional frequencies. The main goal of the LEGS project is to offload services from the DSN through a series of 18-meter, tri-band antennas that will be strategically located at three sites around the Earth to always keep the Moon in view. NASA officials say it will take less time to construct the 18-meter dishes than it takes to construct the 34-meter dishes for DAEP. Since a lot of the future demand will be Moon related, this could help solve the problem.
NASA plans to build the first LEGS ground station in New Mexico, and a second in South Africa, while it evaluates locations for a third station somewhere in Australia. However, according to SCaN’s internal studies, the LEGS project will only be able to address a portion of the excess demand the Agency is projecting. Moreover, the LEGS project is currently only now entering the implementation phase with the Agency continuing to work with stakeholders to define requirements and award contracts for construction. NASA estimates that the three ground stations will not be complete and operational until January 2027. NASA is also planning to procure additional LEGS sites through commercial sources, but details on the locations, contractors, and timing have yet to be determined. The use of such sites would also present security challenges to ensure NASA requirements are met. NASA’s option to utilize partner assets also remains uncertain with international partners such as the European Space Agency predicting that their networks will also be oversubscribed during the DSN’s most demanding periods. Lastly, equipping antennas to send and receive additional frequencies will require additional upgrades to existing infrastructure and will mostly only benefit upcoming missions that are willing to equip their spacecraft to send and receive those frequencies.
In one final statement, they finished by saying, “In our judgment, finalizing requirements for LEGS and hastening work with international and commercial partners to determine the viability of using their assets would provide greater assurance that the Agency will have the DSN capacity required to support its future missions.
Conclusion
NASA is in a tough position as its Deep Space Network is stressed thin due to the increasing number of Deep Space Missions. With the demand only expected to grow in the coming years, the agency needs to solve this issue and soon. We will have to wait and see how it progresses and the impact it has on the space industry.