After reviewing the basics of FET (but discounting the majority of the theories simply because they have not yet been confirmed) I realized that sustained spaceflight is possible with a constantly upward moving flat earth. The spacecrafts would simply require constant upward thrust, which could be possible (although conspiracy may have concealed the existence of this technology). "Orbits" would follow a similar path to the sun and the moon.
Obviously this would change the Conspiracy significantly, however this is not a problem because so little is known about the conspiracy it can be anything.
I believe the conspiracy developed like this:
Earth was believed to be round until the first unmanned object with a camera is sent into space. The true thrust capabilities of the craft is concealed, as it is not yet confirmed. It is able to briefly take pictures of Flat Earth before it is destroyed (as it was designed to orbit Round Earth, not fly above Flat Earth)
These findings are reported to government heads, and the failure is covered up.
The decision is made: the public should not be informed of this revelation until the laws of science in general have been edited to conform to these new findings.
It is soon also discovered that the original craft has the ability to maintain a constant distance between itself and Flat Earth, achieving something similar to a Round Earth orbit.
All spacecraft are designed with a concealed vertical thruster to allow them to travel straight upwards above flat earth.
Manned missions into space occur, but the pictures taken during them are faked in order to not shock the world population.
Moon landings are achieved, but they photos are edited to resemble what would the moon was normally percieved to look like.
I believe this Conspiracy to be more likely for several reasons:
1.It has a clear purpose: to not shock the public with the revelation that the Earth is flat until science has been sufficiently re-written to accomodate that.
2. It is not so grand in scheme, as the majority of spaceflights are now legitimate. This makes the conspiracy much easier to manage
3.Because it is not so grand, it is much less costly to those involved.
Furthermore, since FET's explanatory theories have not been confirmed, when the truth is revealed the scientists working behind the Conspiracy's veil will reveal exactly which theories were correct and which were not (and alternative explanations for the theories that are not.)