Dave Keffer
Corporate Vice President and Chief Financial Officer at Northrop Grumman
Okay. Thanks, Kathy, and good morning, everyone. I also want to thank our team for another year of strong performance in 2022. We won several new franchise programs, delivered industry-leading top line growth and bolstered our talented workforce with the addition of over 6,000 net employees during the year. I'll spend a few minutes on our fourth quarter and 2022 results and then discuss our future expectations in more detail, including our long-term cash flow projections.
We ended the year with nearly $79 billion in backlog, reflecting strong demand for our products and capabilities. We continue to convert our backlog into revenue at an accelerating rate, with fourth quarter sales growth of 16%. This was enabled by our ability to continue strong hiring in Q4, as well as a higher volume of material receipts based on the timing of program demand. The team did an outstanding job of working with our supply chain to secure program material, and for the full year, our sales grew to $36.6 billion, representing organic growth of 3% and exceeding our prior expectations.
Our operating performance and margins remained solid, despite the continued pressures of the macroeconomic environment. Our segment operating margin rate was slightly below our expectations at 11.3% in Q4 and 11.6% for the full year, due in part to the impacts of inflation, which resulted in a lower level of net earnings adjustments, but margin dollar volume was very strong given the top line outperformance. A positive EAC adjustment in the quarter was on B-21, where we recognized a $66 million pickup on the EMD phase of the program, reflecting our latest assumptions regarding future incentives in that phase.
Continuing with our Q4 results. Our transaction adjusted earnings per share was $7.50, a 25% increase over the same period in 2021. Higher EPS were driven by robust growth in our segment top and bottom lines, as well as a lower effective tax rate. The lower Q4 tax rate was driven by the recognition of an $86 million benefit from the resolutions of a Legacy Orbital ATK tax return, which we previewed in our guidance last quarter. And corporate unallocated costs were also below our expectations due to lower state taxes as a result of the R&D tax amortization law not being deferred. For the full year, our transaction adjusted earnings per share were $25.54, well ahead of our guidance range.
Now turning to cash, we had an extremely strong fourth quarter consistent with our historical pattern. For the year, we generated $2.9 billion of operating cash flow and $1.6 billion of transaction adjusted free cash flow, in line with our expectations. This was inclusive of a full year of cash taxes associated with the R&D tax amortization law, as well as our final payment of deferred payroll taxes from the CARES Act legislation.
Moving to our pension plans. Slide 7 in our earnings deck includes our latest assumptions. After three consecutive years of double-digit asset returns, our plans declined by roughly 15% in 2022, in line with market trends. Our FAS discount rate increased roughly 250 basis points to 5.54%, which was the driver of the mark-to-market pension benefit of $1.2 billion reflected in our GAAP results. These factors are also reflected in our latest pension estimates for 2023 to 2025. As we previewed last quarter and updated in our slides today, we're projecting a decline in our non-cash net FAS pension income and an increase in our estimated cash recoveries. In total, our pension plans remain strong. As a result of the higher discount rate our funded status has improved to nearly 100% and we continue to project minimal cash pension contributions over the next several years.
Now turning to 2023 guidance, our revenue expectations have increase from our prior estimates with the midpoint representing nearly 4.5% growth on top of the strong level in 2022. We expect Space Systems to remain our fastest growing business. Sales are projected in the mid $13 billion range, up over $1 billion from 2022 levels, with GBSD and NGI contributing nearly half of the growth and the rest coming from our broad Space portfolio. Mission Systems sales are expected in the high $10 billion range, up mid-single digits, driven by restricted programs in our Networked Information Solutions business. And we continue to expect flattish sales at both Aeronautics and Defense Systems. While programs like B-21 and IBCS continued to grow, headwinds remain on legacy platforms as systems are retired. We expect Aeronautics and Defense Systems to return to growth in 2024.
And similar to our cadence in 2022, we expect first quarter sales of approximately 24% of our full year estimate, with sales ramping again throughout the year. With respect to margins, we expect our 2023 segment operating margin rate to be down roughly 20 basis points from 2022 levels. Challenging macroeconomic conditions, including extended lead times in the supply chain and high levels of inflation continue to put temporal pressure on margins. And while higher CAS recoveries provided a modest benefit to our cash flow in the coming years, they create pressure in our overhead rates and EACs. Similar in nature to what we experienced in the first quarter of 2021 when we recognized a favorable impact from lower projected cash cost, this could lead to an unfavorable margin impact when we update our rates this quarter. We notionally expect this to have a 10 basis point to 20 basis point impact on the full year.
In regards to the B-21 program, we expect the 2023 Contract Award for the first five LRIP lots, with the LRIP phase scheduled to run through approximately at the end of the decade. We are continuing to work with our customer to address macroeconomic risks and enhance efficiencies in the program. As we've described in our 10-K, we do not believe that a loss on the LRIP phase is probable, and therefore, no such loss is reflected in our results or guidance.
Now turning to our future outlook. We expect our 2023 earnings per share to range between $21.85 and $22.45 based on approximately 153 million weighted shares outstanding. This includes $450 million of net pension income, which represents a $4.30 per share headwind compared to 2022. Partially offsetting this non-operational headwind is strong growth in segment performance and the lower share count, which adds roughly $0.90 of additional earnings per share. And lower purchased intangible amortization largely offsets the higher tax rate.
Moving to cash, we expect 2023 adjusted free cash flow between $1.85 billion and $2.15 billion, consistent with our prior outlook as adjusted for current R&D tax law. Although we expect discussions to continue on Capitol Hill, our guidance and multiyear outlook are now based on current tax law for all years and do not include any refunds for R&D taxes paid in 2022.
Capital expenditures are expected to remain elevated at $1.65 million to $1.7 billion in 2023 and a similar level in 2024 before moderating in 2025 and beyond. This is driven by investments to support several large new business wins from 2022. Our guidance assumes we will not have an extended CR, a breach of the debt ceiling or a prolonged government shutdown, as this is our current expectation.
Slide 12 in our earnings deck provides our long term cash outlook, which is predicated on continued top line growth in our business generating strong and gradually expanding operating margins and converting those margins into cash. R&D related cash tax payments should decline by about 20% per year. As I described, capex is expected to remain near 4.5% of sales in 2023 and 2024 before starting to decline in 2025. After investing in our business, we continue to expect to return more than 100% of our free cash flow to shareholders in 2023 in the form of dividends and share repurchases. And we plan to be in the market for new debt issuance soon to support our capital deployment plans, including the refinancing of near-term maturities.
In summary, 2022 was another successful year for Northrop Grumman and we continue to deliver value for our customers, employees and shareholders. And with that, we're ready to take your questions.