EXHIBIT 31.1








CERTIFICATION
OF PRINCIPAL EXECUTIVE OFFICER


UNDER
SECTION 302 OF THE SARBANES-OXLEY ACT








I, Mark
N. Sirangelo, certify that:




1.           I
have reviewed this quarterly report on Form 10-Q of SpaceDev, Inc., a Delaware
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)) and internal control over financial
reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) 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)           designed
such internal control over financial reporting, or caused such internal control
over financial reporting to be designed under our supervision, to provide
reasonable assurance regarding the reliability of financial reporting and the
preparation of financial statements for external purposes in accordance with
generally accepted accounting principles;




(c)           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




(d)           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:  August
14, 2008


/s/ Mark N.
Sirangelo


Mark N. Sirangelo


Chief Executive Officer