NASA's NSSC handles reimbursement for authorized domestic and foreign travel while applying separate rules for rental cars, per diem, extended duty, and Change of Station claims.
NASA's travel reimbursement system covers far more than a routine business trip. The NASA Shared Services Center processes claims for authorized domestic and foreign travel, local assignments, Extended Temporary Duty (ETDY), and Change of Station moves. Each category has its own documentation requirements, accounting logic, and reimbursement rules, so the first control is classification: a short TDY, a prolonged assignment, and a permanent relocation are not interchangeable events.
That division matters because a short domestic assignment is not treated like a transfer to a new duty station. Travelers moving under Change of Station procedures must use dedicated process guidance and forms, while those on Extended Temporary Duty must account for a reduced daily allowance designed around longer stays. NASA's role is therefore procedural and evidentiary: the claim must match the travel category before reimbursement can be evaluated.
The IRS 2026 standard business mileage rate is 72.5 cents per mile, compared with 70 cents in 2025. That figure is a useful tax and reimbursement benchmark for validating privately owned vehicle calculations, but the traveler must still follow the applicable NASA authorization and federal travel rules. On the first and last travel day, the Meals and Incidental Expenses allowance is commonly limited to 75 percent of the applicable M&IE rate.
Rental-car claims are limited to official travel time. If a traveler combines official business with annual leave and keeps the vehicle during that leave, the traveler is responsible for the portion of the rental cost associated with the personal period. Unauthorized use of a government-funded rental automobile can also create additional personal liability. The cleanest record separates official and personal dates, mileage, fuel, parking, and rental charges rather than treating the entire rental period as reimbursable.
Tax treatment requires preparation before departure. NASA travelers are directed to the GSA SmartPay State Tax Information resource to check whether a state or U.S. territory provides an exemption and to obtain any required form. The applicable exemption is determined by jurisdiction and transaction, so retaining the exemption documentation with the travel records can prevent avoidable delays.
IRS high-low per diem figures provide a separate tax-accounting reference for travel beginning on or after October 1, 2025. Under that method, the daily amount is $319 in high-cost locations and $225 elsewhere, with meal allocations of $86 and $74 respectively. These figures should not be confused with every NASA or federal reimbursement rate; an agency authorization, destination-specific table, or foreign-travel rule may control the actual claim.
The authorization can set a lower rate or restrict lodging when the circumstances are known in advance and the change is expected to reduce costs without affecting the mission. NASA's guidance gives lodging obtained at 50 percent of per diem as an example of a situation that should lead to a lower authorized rate. Any such adjustment should be established in the authorization rather than inferred after expenses have already been incurred.
For ETDY lasting more than 90 days, the guidance gives first consideration to long-term lodging facilities. GSA Schedule 48 is designed for stays of 30 days or more and includes furnished apartment- or condominium-style accommodations. NASA also provides a separate document listing expenses included in the reduced ETDY per diem. Travelers should compare the lodging arrangement with that list before assuming that utilities, cleaning, meals, or incidental services are separately reimbursable.
The supporting material covers more than a single voucher. It includes Change of Station voucher information and samples, tax information, RITA guidance, ServiceNow instructions, and the NSSC Change of Station Form. Travelers may also need forms such as OF 1012 for a travel voucher, SF 1038 for an advance of funds, and NASA forms covering service agreements, temporary quarters, residence transactions, property management, and damaged or lost personal property.
Tax issues are handled separately through the Change of Station Taxability Change Notice and Relocation Income Tax Allowance information. The process is not reduced to one universal formula: travelers are directed toward different forms and instructions based on the type of move and the expense involved. As in NASA's scientific and engineering operations, traceable records are essential; however, reimbursement eligibility depends on federal travel policy and substantiation rather than laboratory measurements or clinical endpoints.
The practical lesson is straightforward: NASA travel reimbursement is a rule-based system rather than a single claim pathway. Domestic travelers must control vehicle use and verify tax treatment; ETDY travelers must work within the 65 percent reduced per diem framework; and transferees must assemble relocation-specific documentation. Foreign travelers must also identify whether Department of State rates apply, while travelers to Alaska, Hawaii, or U.S. territories and possessions must use the applicable Department of Defense framework.
The NSSC's value is clearest when travelers identify the correct category before submitting a voucher because the category determines which allowance rules, forms, tax guidance, and rate tables apply. Keeping authorization records, receipts, dates, location data, personal-travel adjustments, and required tax forms together creates an auditable record and reduces the risk that a legitimate mission expense will be delayed or treated as an unsupported claim.
