EXHIBIT
      31.1


CERTIFICATION
        OF PRINCIPAL EXECUTIVE OFFICER
 
 
 I,
        Mark
        N. Sirangelo, certify that:
  1.  I
        have
        reviewed this quarterly report on Form 10-QSB of SpaceDev, Inc., a Colorado
        corporation;
  2.  Based
        on
        my knowledge, this report does not contain any untrue statement of a material
        fact or omit to state a material fact necessary in order to make the statements
        made, in light of the circumstances under which such statements were made,
        not
        misleading with respect to the period covered by this report;
  3.  Based
        on
        my knowledge, the financial statements, and other financial information included
        in this report, fairly present in all material respects the financial condition,
        results of operations and cash flows of the small business issuer as of,
        and
        for, the periods presented in this report;
  4.  The
        small
        business issuer's other certifying officer(s) and I are responsible for
        establishing and maintaining disclosure controls and procedures (as defined
        in
        Exchange Act Rules 13a-15(e) and 15d-15(e)) for the small business issuer
        and
        have:
  (a)  designed
        such disclosure controls and procedures, or caused such disclosure controls
        and
        procedures to be designed under our supervision, to ensure that material
        information relating to the small business issuer, including its consolidated
        subsidiaries, is made known to us by others within those entities, particularly
        during the period in which this report is being prepared;
  (b)  evaluated
        the effectiveness of the registrant's disclosure controls and procedures
        and
        presented in this report our conclusions about the effectiveness of the
        disclosure controls and procedures, as of the end of the period covered by
        this
        report based on such evaluation; and
  (c)  disclosed
        in this report any change in the small business issuer's internal control
        over
        financial reporting that occurred during the small business issuer's most
        recent
        fiscal quarter (the small business issuer's fourth fiscal quarter in the
        case of
        an annual report) that has materially affected, or is reasonably likely to
        materially affect, the small business issuer's internal control over financial
        reporting; and
  5.  The
        small
        business issuer's other certifying officer(s) and I have disclosed, based
        on our
        most recent evaluation of internal control over financial reporting, to the
        small business issuer's auditors and the audit committee of the small business
        issuer's board of directors (or persons performing the equivalent
        functions):
  (a)  all
        significant deficiencies and material weaknesses in the design or operation
        of
        internal control over financial reporting which are reasonably likely to
        adversely affect the small business issuer's ability to record, process,
        summarize and report financial information; and
  (b)  any
        fraud, whether or not material, that involves management or other employees
        who
        have a significant role in the small business issuer's internal control over
        financial reporting.
  
 Date:
        May
        14, 2007      /s/
        Mark N. Sirangelo
 Mark
        N.
        Sirangelo
 Chief
        Executive Officer