Exhibit 5.1
October 2, 2023
Astra
Space, Inc.
1900 Skyhawk Street
Alameda, CA 94501
Re: Registration Statement on Form S-3
Ladies and Gentlemen:
We have acted as counsel
for Astra Space, Inc., a Delaware corporation (the Company), in connection with the registration and issuance of 3,708,520 shares (the Shares) of the Companys Class A common stock, par value $0.0001
per share (the Class A Common Stock) pursuant to: (a) that certain Settlement Agreement and General Release (the Settlement Agreement) dated as of August 14, 2023, as amended by that
certain Amendment to Settlement Agreement and General Release dated as of October 2, 2023 (the Amendment) , each entered into by and between the Company and Fortis Advisors, LLC (the Representative), acting solely
in its capacity as representative of certain converting holders (the Investors) as specified in that certain Agreement and Plan of Merger, dated June 5, 2023, among the Company, Apollo Fusion, Inc.
(Apollo), Artemis First Merger Sub, Inc., Apollo Fusion, LLC and the Representative, pursuant to which the Company acquired Apollo; and (b) the Companys Registration Statement on Form
S-3 (File No. 333-271589) filed by the Company with the Securities and Exchange Commission (the Commission) under the Securities Act of 1933 (the
Securities Act) on May 2, 2023, as amended by Pre-Effective Amendment No. 1 to the Registration Statement on Form S-3, filed with the
Commission on May 4, 2023, as further amended by Pre-Effective Amendment No. 2 to the Registration Statement on Form S-3, filed with the Commission on
May 8, 2023, and declared effective by the Commission on May 16, 2023 (the Registration Statement), and the prospectus dated May 16, 2023, and forming a part of the Registration Statement with respect to the offer
and sale of the Shares, which was included as part of the Registration Statement at the time it became effective on May 16, 2023 (such prospectus, including the documents specifically or deemed to be incorporated therein, the Base
Prospectus).
In rendering the opinions set forth below, we examined and relied upon such certificates, corporate records,
agreements, instruments and other documents, and examined such matters of law, that we considered necessary or appropriate as a basis for the opinions. In rendering the opinions set forth below, we have examined and are familiar with originals or
copies, certified or otherwise identified to our satisfaction, of (a) the Second Amended and Restated Certificate of Incorporation of the Company, as in effect on the date hereof, together with all amendments thereto adopted through the date
hereof as filed in and certified by the office of the Delaware Secretary of State as of September 15, 2023 (b) the Amended and Restated Bylaws of the Company, as in effect on the date hereof, (c) the Registration Statement, the Base
Prospectus, the prospectus supplement dated and filed with the Commission on October 2, 2023 pursuant to Rule 424(b) promulgated under the Securities Act (such prospectus supplement including the documents specifically or deemed to be
incorporated therein, individually and collectively the Prospectus Supplement), (d) the Settlement Agreement, (e) the Amendment, (f) the resolutions of the Board of Directors of the Company relating to, among other
matters, the filing of the Prospectus Supplement and the issuance of the Shares; and (g) such other documents as we have deemed necessary or appropriate as a basis for the opinions set forth below. In our examination, we have assumed the legal
capacity of all natural persons, the genuineness of all signatures, the authenticity of all documents submitted to us as originals, the conformity to original documents of all documents submitted to us as certified or photostatic copies, the
authenticity of the
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