While we weren’t told every missing detail of Space X’s BFR program, Elon Musk’s AMA on Reddit yesterday shed light on some of the company’s future endeavors.
Satellites on Mars
Eyebrows were certainly raised at Musk’s talk at IAC on September 29 where the rumored BFR (Big Fucking Rocket) was documented in concept alongside a plan for the colonization of Mars. Of course, before this is possible, a lot has to happen.
The first step is to place Space X orbiters around Mars to collect the data needed to successfully complete repeated landings and when asked if he plans to launch these satellites Musk simply replied “yes.” These are planned to be launched in the next couple of years, well before any full-scale test of the BFR platform.
Interplanetary Internet
A number of users asked what the plan would be for information exchange between Earth and Mars and after calling one of the space internet fantasists a “nerd”, Musk agreed that a new system would be necessary. He speculated that internet users on Mars would have to request websites or media that would be relayed over an interplanetary backbone to caching systems on or around Mars.
Raptor Thrust
One users asked why the Raptor engines that were being tested for interplanetary trips were reduced from 300 tons of thrust force to 170 and in response to this Musk said that “we chickened out.”
He then went on to explain that first they could do so because the payload mass had decreased but that large, complex engines that are capable of major throttling put “too many eggs in one basket.” Smaller engines that are capable of many stages of throttling are better for operations such as vertical landings and that these will mostly be forged rather than 3D printed.
Musk wrote:
The flight engine design [compared with existing test versions] is much lighter and tighter, and is extremely focused on reliability. The objective is to meet or exceed passenger airline levels of safety. If our engine is even close to a jet engine in reliability, has a flak shield to protect against a rapid unscheduled disassembly and we have more engines than the typical two of most airliners, then exceeding airline safety should be possible.
Planned test flights for on-planet travel
Some users said that they found Musk’s idea to use rockets to travel around Earth an unrealistic one. In response, he said that full scale tests are due to begin in the next couple of years with the first staying low at a couple of hundred kilometers before working their way up to orbital flights.
Multiple rocket stages will still be necessary on Earth, however: “Earth is the wrong planet for single stage to orbit. No problemo on Mars.”
A “weird” space tanker
During the IAC presentation, Musk showed two BFRs refuelling by placing their engine ends together and having fuel flow between them. He explained that these would be the same thing as passenger and cargo versions of the craft without the payload at the front but that the company is working on a dedicated tanker craft with “an extremely high full to empty mass ratio.”
“Warning: it will look kinda weird,” he added.
Head to r/space to see more of Musk’s answers, some of which are incredibly technical.
