The Drive's Impacts
If the drive works as described, it could reduce the costs to launch to those in the range needed to commercialize manned flight. They claim to be able to design a 2G shuttle using it for primary thrust.
Note that a consistent 0.01G (0.1 m/s² vehicle would be capable of making it to mars in a matter of days rather than months. It would be about 15 days, instead of 6 months, at closest approach. A 1G drive reduces closest approach to about 35 hours.
The drive as described uses energy conversion from frequency to kinetic force. Assuming the papers are correct, the measurements weren't fudged, and the apparatus actually operates, it's a potential revolution.
The drive isn't without consumables, however. The drive requires cryogenic cooling. This is as surely a limit as the fuel for an ion thruster. In theory, a sufficiently potent heat pump and radiator system could be used to provide both closed cooling and (very very) miniscule additional thrust. In practice, cryogenic coolants generally are open cycle; using them involves venting them.
The Impact of NASA Confirmation
The impact of NASA replicating the chinese and inventor's results indicates that the drive may have actual validity, and that the physics may be incomplete.
Primarily, it is a credible agency giving a credible result of "apparently works" to a drive that's revolutionary in concept - both concept of design and concept of mode of operation.
Secondarily, it's a clear "Conservation of Momentum needs refinement" result. Until the specific method is evaluated better, it's just a "Useful anomaly" rather than a deal breaker.
If NASA finds it cheap and credible, then it will get tested further (tho' not, of need, by NASA). If that testing bears out the initial findings, then it will lead to commercial use of the drive.
If the drive bears out in orbital flight the tested ratings, then the cascade through physics will include many new theory tweaks trying to explain it, and a lot of tests, until eventually a consensus explanation arises.
Ongoing Testing Notes
Just a note that NASA is apparently still testing the device. source: IFLScience, 3 Nov 2015
24 Apr 2016
on 13 Apr 2016, M.E. McCulloch released a paper, Testing quantised inertia on the emdrive, explaining how the drive works without violating conservation of energy, based upon. Source: arXiv.org > physics > arXiv:1604.03449 Paper is up for peer review. The basis is Unruh Radiation Effect, a not yet widely accepted bit of theoretical physics, which can be used to predict thrust of an EM Drive based upon the chamber, the power, and the wavelengths, and changes in the effective inertial mass of the photon due to frequency shifts as it bounces around. McCulloch does not, however, actually define the maximum theoretically ideal Q value...
Here's the Conclusion of McCulloch:
More than eight tests in four independent labs have shown that when microwaves
resonate within an asymmetric cavity an anomalous thrust is generated pushing
the cavity towards its narrow end.
This force can be predicted fairly well by using a new model for inertia (MiHsC)
which assumes that the inertial mass of the photons is caused by Unruh radiation
whose wavelengths have to fit exactly inside the cavity so that the photons’
inertial mass is greater at the wide end. To conserve momentum a new force
appears to to push the cavity towards its narrow end, and the predicted force
is similar to the thrust observed.
MiHsC suggests that the thrust can be increased by increasing the input power,
the Q factor, or using a dielectric. As a direct test MiHsC predicts that the
thrust can be reversed by making the length L equal to the width of the narrow