39

Neither has much financial purpose without the other. A BFR cannot perform any useful function without an upper stage, and that is the BFS. Since the whole platform is a major investment in a new architecture, they are starting with the smaller piece - the BFS. Since it uses some of the same engines as the BFR, it can act as a testbed for both BFR and BFS ...


29

Elon Musk stated in a news conference after the Falcon Heavy launch that the BFS will be the focus because they think they understand designing booster rockets pretty well, and thus they decided to focus on the more difficult piece first. He answers this in response to a question that starts at 20 minutes 52 seconds here, and speaks specifically to starting ...


21

The dimensions of the test satellites are indeed 400kg each, in a box measuring 1.1 m × 0.7 m × 0.7 m . Something I did not take into account in these calculations is the likely reduction in weight of the satellite during the mass production. For example, the Orbcomm OG2 fleet weighs in at 172 kg per satellite. This is a likely goal for SpaceX's satellites (...


15

This question was actually asked and answered in the announcement itself. Elon Musk: In order to minimize the development risk and cost we decided to commonize the engine between the booster and the ship. A future upgrade path for BFS would be to have a vacuum-optimized nozzle. […] Where you see that cargo around the perimeter, you can actually ...


11

The current cost per launch of Falcon 9 is \$62 million. According to the planned launch cost BFR will be cheaper to launch than Falcon 1. That means it's cheaper than a marginal $7 million per launch. Elon provided a chart that compares the launch costs of different rockets at his BFR presentation: Even when BFR only carries a small payload it will still ...


9

The engines are all now sea level engines, they removed the vacuum ones from version 1.0 to reduce complexity. They did arrange things such that they can add in more engines if required for the future. The bottom area near the engine nozzles now is for storage.


8

Gwynne Shotwell was speaking at a conference and said that at least initially they will be leasing land in Los Angeles near the harbour to build the first BFR units. She specified that the cost to move power lines/lights/trees and so on would be too high to build it at the current factory. It has been noted by fans that the doors on the factory at ...


8

SpaceX won't exit the medium lift market. They plan to use BFR for small payloads too. BFR, unlike Falcon 9 enables reuse of the second stage, they hope this will make BFR cheaper to run than Falcon 9.


8

You can find most of the information you need on the picture below which comes from Reddit. Crucially, if you add up the relevant lines, delta-V from Mars to Earth-Mars transfer is about 5.92 km/s. Assuming they produce the vacuum raptor (not planned for the very first starship missions) Starship will have an $I_{sp}$ around 380s, so by the rocket equation,...


6

The bonus cargo capacity that two different engine types would allow wasn't worth the extra development time, money, and complexity for the initial version. It's designed that in later versions vacuum-optimized engines can be added.


6

Spaceflight 101 gives a throttle range of 20-100% and a sea-level thrust of about 3MN for the Raptor engine, so at minimum thrust it can hover about 60 tons against 1g. Estimates for the dry mass of the superheavy are considerably more than that, closer to 250 tons, so it should have little problem hovering on that level. There is also, though, the question ...


5

SpaceX has not confirmed or denied that they are going to make a "BFR heavy" but there are multiple conceivable reasons why there would not be a "BFR heavy" BFR is aiming for full, rapid turnaround and SpaceX has said that they want to do this very quickly and hopefully fly the same BFR multiple times per day. Adding additional stages would slow down the ...


4

I don't know where construction of BFR will be done, but according to this question, SpaceX is planning to fly the BFR off of launch complex 39A at Cape Canaveral (at least initially). The way your question is worded is a little puzzling; this is on the east coast of the US, which is what allows it to launch to the east without flying overland.


4

More likely the successful relaunch and reuse of Block 5 will speed up BFR production. If the Block 5 is successful, and works for rapid and cheap reuse, then the resources from Falcon 9 will not be as neccasary for future development rather than just producing enough cores and second stages to close out the program.


3

The Starship, BFS vehicle has almost SSTO capability, with very little payload. The less than SSTO mission profile of Earth To Earth suborbital would likely allow single stage operations not requiring the booster at all. There will almost certainly be three different Starship models before Earth to Earth is considered. Cargo (Satellites) Refueling Manned ...


3

Straightforward. SpaceX is Goal-oriented. Better to know your needs up-front and plan around them than the other way around. You start with the intended payload requirements because if you build a Big Rocket and try and cram your payload into it, you soon find you've built a rocket that isn't big enough for what you need, or is inefficient at carrying it, ...


3

Here's a table for gromain's answer, which assumes 400kg/satellite and 12k satellites. It includes prices from spacex's website as a rough estimate. ====reusable===== ===expendable==== F9 FH BFR F9 FH BFR payload to LEO 10t 27t? 150t ...


3

Ignoring the issue that the refueling mode is expected to be tail to tail, and thus blocking the engines, you are trying to re-invent staging. However, with 6 or 9 (IAC 2016 differed from 2017, and will likely differ from reality when it actually flies) or whatever the current design has in terms of Raptor Vac engines, the booster is quite sufficiently ...


2

No, this is not viable for SpaceX. If they used a booster to do the Trans-Mars orbit insertion burn, so the upper stage can save it's fuel, then the booster would not be recoverable. The booster would be traveling too fast to turnaround and land back on Earth. Elon Musk is all about not throwing away his rockets. He would see this as not being viable.


2

I agree with the lift capacity of BFR at 304 Starlink satellites, by weight and probably dimensionally. But there is the problem of each orbital plane on the first Starlink Phase I only has 34 satellites in it. See the section on "How many launches...". But changing from one orbital plane to another costs a substantial amount of fuel, it is unlikely that ...


1

Beyond the thrust vs empty mass of the different vehicles allowing hover, it seems that SpaceX has managed to figure out how to successfully hover slam, so this might be less of an issue. But other features may help. Being much bigger makes reentry easier, having a larger surface to distribute heating loads. Additionally, specifically for the Super Heavy ...


1

As with all orbital rockets, you have essentially two parts - upper stage & payload (BFS) and the means to boost it to orbit (BFR). If you finalize the design of your booster first, that will set limits on what sort of upper stage/payload you can launch with it. Finalize the design of your payload first, and you then get to design a booster that gets it ...


1

I think it's unlikely. Getting falcon heavy to work was far more work than they expected and the BFR second stages are supposed to be reusable (unlike the falcon 9 second stages which are expendable).


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