| UNITED STATES | 
| SECURITIES AND EXCHANGE COMMISSION | 
| Washington, D.C. 20549 | 
| SCHEDULE 14A | 
| (Rule 14a-101) | 
| Schedule 14A Information | 
| Proxy Statement Pursuant to Section 14(a) of the | 
| Securities Exchange Act of 1934 | 
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Filed by a Party other than the Registrant ☐
Check the appropriate box:
| ☐ | Preliminary Proxy Statement | 
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| ☐ | Definitive Proxy Statement | 
| ☒ | Definitive Additional Materials | 
| ☐ | Soliciting Material Pursuant to §240.14a-12 | 
| Astrotech Corporation | 
| (Name of Registrant as Specified in Its Charter) | 
| (Name of Person(s) Filing Proxy Statement, if other than the Registrant) | 
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