Filed Pursuant to Rule 424(b)(3)

Registration No. 333-257930

PROSPECTUS SUPPLEMENT NO. 1

(to Prospectus dated August 12, 2021)

ASTRA SPACE, INC.

Primary Offering Of

15,333,303 Shares of Common Stock

Secondary Offering of

189,026,575 Shares of Common Stock

5,333,333 Warrants to Purchase Common Stock

This prospectus supplement amends and supplements the prospectus dated August 12, 2021 (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 11, 2021 (the “Current Report”). Accordingly, we have attached the Current Report to this prospectus supplement.

The Prospectus and this prospectus supplement relate to the issuance by us of up to an aggregate of (i) 9,999,970 shares of our Class A common stock that may be issued upon exercise of warrants to purchase Class A common stock at an exercise price of $11.50 per share (the “public warrants”) issued by Holicity Inc. (“Holicity”) in its initial public offering; and (ii) 5,333,333 shares of our Class A common stock that may be issued upon exercise of private placement warrants at an exercise price of $11.50 per share that were originally sold to X-icity Holdings Corporation (the “Sponsor”) in a private placement consummated simultaneously with Holicity’s IPO (the “private placement warrants” and, together with the public warrants, the “warrants”).

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) 5,333,333 private placement warrants; (ii) up to an aggregate of 5,333,333 shares of our Class A common stock that may be issued upon exercise of the private placement warrants held by the Selling Securityholders; (iii) 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); (iv) 7,500,000 shares of Class A common stock issued to the Sponsor prior to Holicity’s initial public offering and registered for sale by the Selling Securityholders; (v) 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); (vi) 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 (vii) 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 common stock and warrants are listed on Nasdaq under the symbols “ASTR” and “ASTRW”, respectively. On August 11, 2021, the closing price of our common stock was $10.77 per share and the closing price of our warrants was $3.38 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 15 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 August 13, 2021.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): August 11, 2021

Astra Space, Inc.

(Exact name of Registrant as Specified in Its Charter)

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

(Former Name or Former Address, if Changed Since Last Report)

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:

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.  ☐

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

New Director Appointment

Effective August 10, 2021, the Board of Directors (the “Board”) of Astra Space, Inc. (the “Company”) appointed Michèle A. Flournoy, age 60, as an independent director of the Company and also appointed her as the Chairperson of the Nominating and Corporate Governance Committee.

Ms. Flournoy career has spanned a range of roles in the Defense industry, ranging from research to advisory. She is the co-founder and managing partner of WestExec Advisors, a strategic advisory firm formed in early 2018. She previously served as the Under Secretary of Defense for Policy from February 2009 to February 2012, acting as principal advisor to the Secretary of Defense in the formulation of national security and defense policy, oversight of military plans and operations, and in National Security Council deliberations. She led the development of the Department of Defense’s 2012 Strategic Guidance and represented the Department in dozens of foreign engagements, in the media and before Congress. Ms. Flournoy co-founded the Center for a New American Security (“CNAS”), a bipartisan think tank, in 2007 and serving as President until 2009. She returned to serve as the CEO of CNAS from July 2014 through December 2017. Ms. Flournoy is also the recipient of numerous honors and awards, and has edited and authored various works on a broad range of defense and national security issues. In addition, Ms. Flournoy has also served on numerous business and advisory boards such as Booz Allen Hamilton, Spirit of America, The U.S. Naval Academy Foundation, CARE and the Honorary Advisory Committee of The Leadership Council for Women in National Security. Ms. Flournoy is also a former member of the President’s Intelligence Advisory Board, the CIA Director’s External Advisory Board, and the Defense Policy Board, and is currently a member of the Council on Foreign Relations and the Aspen Strategy Group, and is a Senior Fellow at Harvard’s Belfer Center for Science and International Affairs.

Ms. Flournoy does not have any family relationships with any of our executive officers or directors. There are no arrangements or understandings between Ms. Flournoy and any other person pursuant to which she was appointed to serve on the Board. Ms. Flournoy has no direct or indirect material interest in any transaction required to be disclosed pursuant to Item 404(a) of Regulation S-K.

For her service as a director, Ms. Flournoy will be paid the compensation set forth in Item 8.01 Other Events of this Form 8-K, which is incorporated by reference in this Item 5.02.

Item 8.01 Other events

On August 10, 2021, the Board changed its independent director compensation policy effective June 30, 2021, to provide each independent director an annual retainer of $250,000, which will be paid in a combination of no more than $87,500 in cash and the issuance of stock options and/or restricted stock units having a value equal to at least $162,500. The Board also set its annual retainers for its lead independent director, committee chairs and committee members as follows:

The Company will pay fees for service on committees in cash. The director compensation set forth here replaces the director compensation previously announced in our Form S-1, filed with the SEC on July 1, 2021, and amended by those certain registration statements on Form S-1/A filed on July 30, 2021 and August 10, 2021.

On August 11, 2021, the Company issued a press release announcing the appointment of Ms. Flournoy to the Board. A copy of the press release is attached hereto as Exhibit 99.1.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

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.

Exhibit 99.1

Michèle Flournoy Joins Astra Board of Directors

Former Under Secretary of Defense joins Astra board as chair of nominating and governance committee

Alameda, California. August 11, 2021. Astra Space, Inc. (“Astra”) (Nasdaq: ASTR), today announced that Michèle Flournoy has been appointed to Astra’s Board of Directors and will chair the Board’s Nominating and Corporate Governance committee, effective August 10, 2021.

Flournoy was the highest-ranking woman in the Department of Defense when she served President Obama as the Under Secretary of Defense for Policy from February 2009 to February 2012, acting as principal advisor to the Secretary of Defense in the formulation of national security and defense policy, and in National Security Council deliberations. She led the development of the Department of Defense’s 2012 Strategic Guidance and represented the Department in dozens of foreign engagements, in the media and before Congress. Flournoy is also the recipient of numerous honors and awards, including the Chairman of the Joint Chiefs of Staff’s Joint Distinguished Civilian Service Award in 2000, and has authored various works on a broad range of defense and national security issues.

“Michèle is an extraordinary executive and uniquely qualified to provide guidance and insight on our aspiration to provide launch services to government and commercial customers.” said Chris Kemp, Founder, Chairman and CEO of Astra. “She is not only a respected and adept defense industry advisor but also possesses a genuine entrepreneurial spirit as co-founder of two respected and successful organizations.”

Flournoy served under President Clinton as Deputy Assistant Secretary of Defense for Strategy as well as principal Deputy Assistant Secretary of Defense for Strategy and Threat Reduction. Flournoy is the co-founder and managing partner of WestExec Advisors, and serves on several non-profit boards including The Center for a New American Security (CNAS), CARE, The Mission Continues, and the Honorary Advisory Committee of The Leadership Council for Women in National Security. She is also a former member of the President’s Intelligence Advisory Board, the CIA Director’s External Advisory Board, the Defense Policy Board, and is a Senior Fellow at Harvard’s Belfer Center for Science and International Affairs.

“Space is the ultimate high ground,” said Flournoy, “I’m excited to help lead Astra’s effort to launch the next generation of space services and usher a new era of American innovation in space.”

About Astra

Astra’s mission is to improve life on Earth from space by creating a healthier and more connected planet. Astra’s first flight to space was within 4 years of its inception, making it the fastest company to reach space. Visit www.astra.com to learn more about Astra.

Safe Harbor Statement

Certain statements made in this press release are “forward-looking statements”. Forward-looking statements may be identified by the use of words such as “anticipate”, “believe”, “expect”, “estimate”, “plan”, “outlook”, and “project” and other similar expressions that predict or indicate future events or trends or that are not statements of historical matters. These forward-looking statements reflect the current analysis of existing information and are subject to various risks and uncertainties, As a result, caution must be exercised in relying on forward-looking statements. The following factors, among others, could cause actual results to differ materially from those described in these forward-looking statements: (i) our failure to meet projected development and launch targets, including as a result of the decisions of governmental authorities or other third parties not within our control; (ii) changes in applicable laws or regulations; (iii) the ability of the Astra to meet its financial and strategic goals, due to, among other things, competition; (iv) the ability of Astra to pursue a growth strategy and manage growth profitability; (v) the possibility that Astra may be adversely affected by other economic, business, and/or competitive factors; (vi) the effect of the COVID-19 pandemic on Astra and (vii) other risks and uncertainties described discussed from time to time in other reports and other public filings with the Securities and Exchange Commission, including our registration statements and quarterly reports.

Media Contact:

Kati Dahm

kati@astra.com

Investor Contact:

Dane Lewis

dane@astra.com