NASA's Roman telescope used 18 kg of fuel in first course correction, not 200 kg
NASA says the first mid-course correction used 18 kg of fuel instead of the budgeted 200 kg, leaving fuel for at least 22 years of operations against a 10-year design.
NASA's Nancy Grace Roman Space Telescope executed its first mid-course correction on Aug. 31 with more than 99% accuracy, according to science.nasa.gov. The maneuver required about 40 pounds (18 kilograms) of fuel, less than 10% of the 441 pounds (200 kilograms) the team had budgeted. science.nasa.gov
science.nasa.govscience.nasa.govOpen source ↗ Together with other savings, this is expected to more than double the mission's potential operational lifetime.
Fuel budget and mission lifetime
Roman was designed for a five-year primary mission plus a five-year extended mission, which gives a 10-year fuel budget in total. Fuel is the observatory's primary consumable resource, so any savings could enable observations beyond the 10-year design life.
Jamie Dunn, director of NASA's Goddard Space Flight Center in Greenbelt, Maryland, said that Roman has fuel for at least 22 years of potential science operations. He credited the orbital dynamics team's planning, the operations team's execution and a precise launch from SpaceX.
The added life comes from three sources: the accuracy of the first correction, extra fuel loaded before launch, and the anticipated results of the second correction and orbital insertion. science.nasa.gov
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Why the tanks held more
The extra fuel loaded at launch could enable roughly four more years. The surplus exists because Roman launched lighter than planned. The team had budgeted fuel for a conservative maximum weight of 21,605 pounds (9,800 kilograms), while the observatory's actual weight was 17,760 pounds (8,056 kilograms).
The lighter spacecraft needed less fuel for the correction, and the lower weight left room to fill the propellant tanks beyond what the 10-year mission required. Alison Rao, Roman propulsion lead at NASA Goddard, explained that the budget is based on a set maximum mass so the supply does not fall short. The team also tracks the propellant needed from the actual mass throughout integration and testing.
Second burn and orbit at L2
Because the first correction was accurate, the second burn is expected to be very small and to save more fuel. The team can also wait longer to conduct it. The burn will give the observatory the last bit of energy needed to reach its targeted position before it maneuvers into its final orbit at L2, about 100 days after launch, or about early December. science.nasa.gov
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According to current projections, both maneuvers will use less fuel than planned. Once in orbit around L2, Roman will need only periodic station-keeping burns roughly every 28 days.
