Primary Offering Of
15,333,303 Shares of Class A Common Stock
Secondary Offering of
189,026,575 Shares of Class A Common Stock
This prospectus supplement amends and supplements the prospectus dated July 14, 2022 (as supplemented or amended from time to time, the
Prospectus), which forms a part of our Registration Statement on Form S-1 (No. 333-257930). 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, filed with the Securities and Exchange Commission on August 29, 2022 (the Current
Report). Accordingly, we have attached the Current Report to this prospectus supplement.
The Prospectus and this prospectus supplement also relate
to the offer and sale, from time to time, by the selling securityholders named in this prospectus (the Selling Securityholders), or any of their permitted transferees, of (i) up to an aggregate of 20,000,000 shares of our
Class A common stock that were issued to certain investors (collectively, the PIPE Investors) in a private placement in connection with the closing of the Business Combination (as defined herein); (ii) 7,500,000 shares of
Class A common stock issued to the Sponsor prior to Holicitys initial public offering and registered for sale by the Selling Securityholders; (iii) up to an aggregate of 92,277,793 shares of Class A common stock that were issued
to certain affiliates of Astra (collectively, the Astra Affiliates) pursuant to the Business Combination Agreement (as defined herein); (iv) up to an aggregate 56,239,188 shares of Class A common stock issuable upon conversion (on a
one-for-one basis) of shares of our Class B common stock, par value $0.0001 per share (Class B Common Stock) held by certain Selling
Securityholders and (v) up to an aggregate of 7,676,261 shares of our Class A common stock issued in connection with our acquisition of Apollo Fusion, Inc. (Apollo Fusion), which closed on July 1, 2021 comprised of (x)
2,558,744 shares of our Class A common stock (the Initial Apollo Shares) issued to certain of the Selling Securityholders on July 1, 2021, in connection with our merger with Apollo Fusion, Inc. (Apollo Fusion) and
(y) 5,117,517 additional shares of our Class A common stock (the Additional Apollo Shares) which may be issued to certain of the Selling Securityholders assuming (a) the achievement of all remaining performance milestones set
forth in the Apollo Fusion Merger Agreement (as defined herein), (b) we elect to pay all future milestone consideration in shares of our Class A common stock as required by the terms the Apollo Fusion Merger Agreement, and (c) the per
share price used to calculate the number of shares of our Class A common stock to be issued is $11.7243, which is the same per share price used to calculate the number of Initial Shares issued to the Selling Securityholders. The Additional
Shares have not been earned and are not currently outstanding. The actual number of Additional Shares issued to the selling stockholders could be materially greater or less than 5,117,517 shares of Class A common stock depending whether and to
what extent the future performance milestones are met and/or the actual average closing price of our Class A common stock at the time such milestones are achieved. The Prospectus and this prospectus supplement also cover any additional
securities that may become issuable by reason of share splits, share dividends or other similar transactions.
Our Class A common stock is listed on
Nasdaq under the symbol ASTR. On August 26, 2022, the closing price of our Class A common stock was $0.94 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.