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Accounts Payable

Welcome to NSSC Accounts Payable where we process all accounts payable invoices, centrally billed accounts, and government charge card transactions for the Agency.

Vendor Payment

NASA is committed to expedient and accurate payment of invoices.  Any questions or inquiries should be addressed to the Contracting Officer designated on your award or to the NSSC Customer Contact Center.

NSSC Customer Contact Center telephone: 1-877-677-2123 (1-877-NSSC123)
Fax: 1-866-779-6772 (1-866-779-NSSC)

Vouchers and invoices are to be submitted in the Treasury’s Invoice Processing Platform for awards that include the new voucher or invoice submission clause, 48 CFR § 1852.232-80.


  • In the case of commercial item contracts, electronic invoicing is allowed via the IPP Portal.
  • Invoices for awards in closeout should be submitted via hardcopy/e-mail/fax to one of the addresses at the bottom of the page.

For assistance with IPP, please use the contact information below:

If your award does not include 48 CFR § 1852.232-80, invoices are to be submitted in one of the following ways until you receive a modification from the NASA Contracting Officer to change your invoice/voucher submission:

via e-mail to:
via hardcopy paper to: 
NSSC – FMD Accounts Payable
Building 1111, Jerry Hlass Road
Stennis Space Center, MS  39529

Payment Status

For payment status questions or problems, vendors and employees should contact the NSSC Customer Contact Center.

How to Avoid Delayed Payment from the NSSC

We try very hard to ensure all payments arrive in a timely fashion. Occasionally, payments take longer to process than expected. Sometimes, invoices are returned to the vendor because they do not comply with the payment terms of the contract or problems processing the invoice delay payment. To facilitate processing of your invoice and to expedite your payment, we compiled the following list of reasons payments are delayed:

The invoice does not contain the following information per the Prompt Payment Act:

  • Vendor name
  • Contract/purchase order number
  • Date
  • Amount
  • Shipping and/or payment terms
  • Invoice number
  • Description of service/good invoiced
  • The invoice was not sent to the correct Designated Billing Office (DBO).
    Check your contract/purchase order to ensure that the NSSC is the proper Designated Billing Office.
  • Incorrect banking information for payment
  • Partial shipments or billings not stated in terms or conditions of contract
  • Submission of multiple invoices in one e-mail or fax
  • Encryption of email
  • Embedding multiple invoices or instructions and complicated attachments in e-mails
  • Invoice or file is not in a standard print format (Word, Excel or PDF)
  • Submission of documents as Microsoft Document Writer images and some TIFF applications

If your invoice form does not contain this information you may want to use the Standard Form (SF) 1034.

Check the Status of an Invoice Payment from NASA

To check the status of your payment or if you have a payment problem, you can contact the NSSC by:

Calling the NSSC Customer Contact Center at: 1-877-677-2123 (1-877-NSSC123)
Faxing your inquiry to: 1-866-829-6772

When you contact the NSSC, please have the following information on hand:

Vendor Name
Contract/Purchase Order Number
Date Submitted to Designated Billing Office
Invoice Number
Invoice Amount
Applicable NASA Center

Collections for NASA Vendor Over-Payments

Vendor overpayments that are due back to NASA can be made via cash, checks, or electronically at the Pay NASA link. Payments
Payments may also be made using the payment system. has been developed to meet the Department of the Treasury’s Financial Management Service Division’s commitment to process collections electronically.

  • is a secure, government-wide, internet collection portal.
  • provides the ability to make payments by check, credit card, or debit card 24 hours a day.  
  • is web based, allowing customers to make payments from any computer with Internet access.
  • does NOT require a login ID or password to use the service.

For check payments in you will need:

  • Company/Contact Information
  • ABA Routing Number
  • Checking Account Number
  • Check Number
  • NASA Center to be paid
  • Bill or Debt ID #

For credit or debit card payments, you will need:

  • Company/Contact Information
  • Debit or Credit Card
  • NASA Center to be paid
  • Bill or Debt ID #

For more information, please visit the Accounts Receivable page.

Payment Cut-Off Dates

In order for the NSSC to receive confirmation of vendor disbursements by Treasury, payments are cut off (not processed) three business days prior to the last day of the month.

For FY2023 the last day for processing vendor payments to Treasury is September 26, 2023.  The next day for payments will begin on October 2, 2023.

The established monthly cut-off dates for payments are listed below:

Vendor References

IRS 1099-MISC Form Instructions

Prompt Payment Rule

NASA FAR Supplement

Small Business Administration

Submitting Proper Invoices to NASA

Make certain your invoice contains all the information stipulated in the Invoicing clause of your contract to avoid delays and expedite the payment process. Generally, each Invoicing clause requires the following:

  • Name and Address
  • Invoice Date/Number
  • Contract/Purchase Order Number
  • Description of Goods or Services (CLIN, QTY, U/P), Quantity, Unit Price, Total Amount of Invoice
  • Taxpayer Identification Number (TIN) (if applicable)

All vouchers for cost reimbursable contracts have to be submitted through IPP. 

Before you submit your invoice for payment, please check each contract/purchase order to see where invoices for each contract/purchase order are to be submitted.

System for Award Management (SAM) for NASA Vendors

System for Award Management (SAM) for NASA Vendors

Payments against NASA contracts and other procurement actions are made by the NSSC. In order to better align with Federal-wide vendor databases, NASA uses the System for Award Management (SAM) to validate vendor information across all of the Agency’s Integrated Enterprise Management (IEM) business systems. NASA payments to vendors are processed using the banking information in SAM.

To ensure continued accurate and prompt payments, please maintain a current registration, including banking information in SAM.  SAM can be accessed at
If you need assistance registering or have questions about SAM, contact the SAM Help Desk at
NASA will use the clause at FAR 52.232-33 in contracts as the default Electronic Funds Transfer (EFT) requirement. 

Please note that any information provided in your registration may be shared with authorized federal government offices. Registration does not guarantee business with the federal government.