It's been only one month since the success of the first SpaceX Crew Dragon launch, but NASA has already modified SpaceX's contract to allow the company to launch astronauts on reused rockets and spacecraft.  This is a big jump for NASA, which is confident in SpaceX's promises despite one of its reusable rockets exploding the day before its successful launch of astronauts to the International Space Station (ISS).  The idea of reusable rockets is to make them capable of powering multiple trips into space, thus dramatically lowering the cost of travel and making commercial activities possible.  

In the case of SpaceX, NASA is rewarding technology that isn't quite ready to go.    

NASA has tried this technology in the past but had little success.  NASA did eventually develop reusable rockets during the Shuttle missions, but they proved to be much more difficult to operate than anticipated, resulting in expenses rising 4,000 percent above estimates to over a billion dollars a flight.  Refurbishment fell below expectations, with the shuttle taking an average of 80 days for repairs rather than the seven days NASA initially projected. 

As NASA tried unsuccessfully to produce efficient reusable rockets, other nations like Russia completed more practical projects and innovations, giving America no choice but to start making greater use of lower-cost foreign rockets to conduct missions.  While this put an end to NASA's pursuit of reusables, Elon Musk, Jeff Bezos, Richard Branson, and other venture capitalists' entry into the space marketplace has brought the idea back.  Venture capitalism is about taking huge risks with the hopes of huge rewards, but the trouble is that they are not experimenting independently.  They have roped NASA back into participating in this endeavor yet again before working out all the kinks. 

Seemingly forgetting their agency's failed history of making reusables operational, leadership at NASA have begun doling out government contracts.  The results have been predictable.  While these companies' reusable projects have had some things to cheer about over the years, they continue to run into many of the same problems NASA faced in terms of ensuring steady cost savings and adequate reliability.  

The promise of reusable parts that would lower expenses hasn't panned out the way many have hoped.  Similar to how NASA saw issues with engine repairs and other failures that drastically raised launch prices, these private firms have seen accidents, cost overruns, and a frequent inability to actually recycle the parts they have deemed "reusable." 

Limited payloads have also been a struggle for some time, as reusables' carrying capacity is much lower than that of a single-use rocket and often makes the projects not worth the cost.  Making matters worse in SpaceX's case is that it has overestimated the cost-savings for its reusable endeavors in the past.  For example, in one mission, SpaceX had to raise its price by fifty percent compared to what it had offered previously after getting "a better idea of the costs involved."  It had to do this despite already having the highest price of the three contractors competing for contracts with that mission.

NASA wants reusable technology to be ready so it can make interplanetary exploration affordable and practical.  But in the process, it may have let dreams get in the way of reality.   

If these rockets were already reliable, Musk wouldn't be dedicating his entire team to working on the project in the aftermath of an explosion.  Reusables may be the future of space travel and commerce, but taxpayer money and astronauts should not be the test subjects

As a scientist, I believe in empirical data.  In the realm of the government, events can and should be replicated consistently before the government decides to make use of technology that's critical for national security.  Until there is more concrete evidence of reusable rockets' reliability and safety, the national space program should refrain from including them further in future space operations. 

Phil Kiver, Ph.D., is an Army veteran of Iraq and Afghanistan.  He received his doctorate in strategic studies at Henley-Putnam University.