Filed Pursuant to Rule (424)(b)(3)

Registration No. 333-267113

PROSPECTUS SUPPLEMENT NO. 23

(to Prospectus dated September 13, 2022)

ASTRA SPACE, INC.

34,000,000 SHARES OF CLASS A COMMON STOCK

This prospectus supplement amends and supplements the prospectus dated September 13, 2022 (as supplemented or amended from time to time, the “Prospectus”), which forms a part of our Registration Statement on Form S-1 (No. 333-267113). This prospectus supplement is being filed to update and supplement the information in the Prospectus with the information contained in our Current Report on Form 8-K/A, filed with the Securities and Exchange Commission (the “SEC”) on March 13, 2023 (the “Current Report”), which amended our Current Report on Form 8-K, filed with the SEC on March 13, 2023. Accordingly, we have attached the Current Report to this prospectus supplement.

The Prospectus and this prospectus supplement relate to the offer and resale of up to 34,000,000 shares of Class A Common Stock, par value $0.0001 per share (the “Class A Common Stock”), of Astra Space, Inc. by B. Riley Principal Capital II, LLC (the “Selling Stockholder”). The shares included in the Prospectus and this Prospectus supplement consist of shares of Class A Common Stock that we may, in our discretion, elect to issue and sell to the Selling Stockholder pursuant to a common stock purchase agreement we entered into with the Selling Stockholder on August 2, 2022 (the “Purchase Agreement”). Such shares of Class A Common Stock include (i) up to 33,281,805 shares of our Class A Common Stock that we may, in our sole discretion, elect to sell to the Selling Stockholder from time to time after the date of this prospectus, pursuant to the Purchase Agreement and (ii) 718,195 shares of our Class A Common Stock we issued, or may issue if certain conditions are met, in each case, to the Selling Stockholder as consideration for its commitment to purchase shares of our Class A Common Stock in one or more purchases that we may, in our sole discretion, direct them to make, from time to time after the date of this prospectus, pursuant to the Purchase Agreement. See “The Committed Equity Financing” for a description of the Purchase Agreement and “Selling Stockholder” for additional information regarding the Selling Stockholder.

Our Class A common stock is listed on Nasdaq under the symbol “ASTR”. On March 10, 2023, the closing price of our Class A common stock was $0.4307 per share.

This prospectus supplement updates and supplements the information in the Prospectus and is not complete without, and may not be delivered or utilized except in combination with, the Prospectus, including any amendments or supplements thereto. This prospectus supplement should be read in conjunction with the Prospectus and if there is any inconsistency between the information in the Prospectus and this prospectus supplement, you should rely on the information in this prospectus supplement.

Investing in our securities involves risks that are described in the “Risk Factors” section beginning on page 17 of the Prospectus.

Neither the SEC nor any state securities commission has approved or disapproved of the securities to be issued under the Prospectus or determined if the Prospectus or this prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is March 13, 2023.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K/A

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): March 10, 2023

Astra Space, Inc.

(Exact name of Registrant as Specified in Its Charter)

Registrant’s Telephone Number, Including Area Code: (866) 278-7217

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Explanatory Note

This report amends the Current Report on Form 8-K of Astra Space, Inc. (the “Company”), dated March 10, 2023 and filed with the Securities and Exchange Commission on March 13, 2023 (the “Original 8-K”), solely to clarify that, as of March 13, 2023, the Company has access to all of its cash held on deposit with Silicon Valley Bank, Santa Clara, California, (“SVB”). This report does not otherwise amend, modify or update any of the disclosures contained in the Original 8-K.

Consistent with the joint statement released on March 12, 2023 by the Secretary of the Treasury, the chair of the Federal Reserve Board and the chairman of the Federal Deposit Insurance Corporation, the Company has confirmed that it has access, as of March 13, 2023, to all of its cash held on deposit with SVB, which represents approximately 15% of the Company’s current cash, cash equivalents and marketable securities.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.