If one is to take anything at all away from Elon Musk’s update to SpaceX’s planetary colonization strategy on September 29, it ought to be the tangible and undeniable progress the company has made with real, Mars-focused hardware development.
To take Musk at his word, the general atmosphere pervading the two relevant programs is one of extreme success and confidence. Raptor, the powerful methane-oxygen rocket engine intended to be the workhorse for any larger launch vehicle, has conducted dozens (42, to be specific) of successful hot fires at SpaceX’s McGregor, Texas testing facilities. These ranged from a handful of seconds all the way to 100 seconds in duration, and Musk made it explicitly clear that the only limiting factor to test duration was the size of the tanks of propellant available to fuel the engine. Of crucial importance is the fact that the engine being tested in Texas is a subscale prototype, and is not representative of the final engine. However, SpaceX has since shrunk the final target for operational Raptors, and this means that the current scale is not far off from the final thrust figure. The prototype Raptor is believed to have a thrust of approximately 1,000 kN (Kilonewtons), with slides from Musk’s 2017 presentation pointing to a full scale thrust of 1700 kN, far closer to becoming real than the 3,000 kN figure given at the 2016 IAC.
SpaceX has completed over 1,200 seconds of firing across 42 main Raptor engine tests. pic.twitter.com/EhxbPjd8Cj
— SpaceX (@SpaceX) September 29, 2017
Possibly even more significant is the reported success SpaceX has had with the construction and stress testing of a full-scale carbon fiber liquid oxygen tank, which was tested to a very eventful destruction on Washington state’s Puget Sound. Fans closely followed this series of tests, but information was scarce and the general consensus was that the tank had failed unintentionally during those tests. The fact that Musk claimed that the 12 meter diameter tank was “successfully tested” at high pressures, as well as the confidence he expressed about a uniquely capable “carbon fiber matrix”, suggest that SpaceX have leaped over one of biggest potential hurdles of their larger vehicle plans. Carbon fiber propellant tanks have the potential to make rockets significantly lighter and thus more efficient, particularly if no internal liner of metal is needed to ensure the safety of those carbon fiber tanks. One might remember the difficulties SpaceX had with supercool liquid oxygen, culminating in the Amos-6 mishap that saw carbon fiber helium tanks clash with SpaceX’s then-new supercooled propellant procedures.
Through many challenging mistakes, SpaceX has learned the hard way that extra care must be taken when mixing carbon fiber and liquid oxygen. The telltale sign that SpaceX has, however, successfully learned from those mistakes can be found in the company’s aspiration to begin construction of the first BFR cargo ship as early as April of 2018, barely six months from today. Time will tell if they can maintain that aggressive schedule and launch two Mars-bound cargo ships in 2022. The company’s incontrovertible success with the development of Raptor engines and carbon fiber propellant tanks bode extremely well for the future of their planetary colonization efforts.