You are not on spacex.com, but instead on spacetwitter.com.
This is due to an update to the iOS Twitter (now X) client which, as of April 8, 2024, it automatically replaces the text "twitter.com" to "x.com" as part of its functionality.
Unfortunately, it appears to do that regardless of where "twitter.com" or "x.com" is located.
For example, a URL that appears to be "spacex.com" will actually redirect to "spacetwitter.com" when it's clicked on.
Please be aware that there is a potential for this feature to be exploited in the future, by acquiring domains containing "twitter.com" in order to redirect users to malicious websites.
For this reason, this domain has been acquired to prevent its use for malicious purposes.
Thank you for your understanding.