# Tag Info

49

Starship alone is not capable of orbital flight, but it is capable of high suborbital flights sufficient for testing reentries. The booster's only use is as a first stage for Starship. It could only be put into use immediately if a Starship has been developed and built to stack on top of it. And it is expected to be much quicker and easier to develop than ...

40

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 ...

30

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 ...

23

While this seems lightly ill conceived, it actually makes sense. Super Heavy is going to be very large, as these things go. 70m tall, 9m wide, and while not very dense, still quite heavy. Not very easy to move around. The plan is to land close by to make moving it back to the launch pad easier. Original plan was notionally to land back on the launch ...

21

EDIT: With the third Starlink launch happening about right now, it's time to update this answer! We now know that each satellite has a weight of 260kg, and that they launch 60 satellites per mission. They are flat packed, stacked 30 up side by side in the Falcon 9 Fairing, and far smaller than what I thought would be possible in my first answer. Elon Musk ...

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 switch out ...

12

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

In simplified terms, the list of minimum requirements for completing the missions Starship is set to do is much longer and more complex than that for Superheavy. For Earth Orbit or Lunar missions, the Starship absolutely needs to: Launch Perform orbital insertion Rendezvous and Dock Maintain life support / functionality in long-term spaceflight Orbital ...

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.

9

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

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

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 ...

6

I mean what is he going to do with the ship alone? Develop it. Test it. Verify it. Perform suborbital flights. Remember that SpaceX is also toying with the idea of offering point-to-point passenger service on Earth. (Personally, I believe that will not happen, though.) Is it even capable of orbital flight on its own? No, but for testing launch and landing ...

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.

4

How strong would the blast yield be? Probably not very. Rocket explosions usually consist of an initial small blast that blows the fuel in one direction and the oxidizer in the other. The fuel ignites, but since it's not mixed with the oxidizer, it burns at the interface between the fuel and the surrounding air, and doesn't generate much of a shock wave. ...

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 ...

2

The breakthrough idea and most demanding engineering task of Starship/SH is complete re-usability of the orbital vehicle. If you tried to reach orbit with Super Heavy alone-- it's not designed for this and so I'm not sure it's even possible-- it would just be a large expendable booster, which might well be more expensive to operate than the partially-...

2

An important point to understand: it is not as simple as "just put this stage on that booster." Real life is more complicated than Kerbal Space Program. There is a lot of design, test, and certification work that has to be done before using a certain stage combination -- time that is better spent working on Starship -- so the SuperHeavy booster is ...

1

The reason why the landing pad is so close to the launchpad is for SpaceX to be able to launch rockets as frequently as possible. In the announcement of Starship and Superheavy, we see that SpaceX is planning to launch a rocket more than once in a day as they are planning to create an Interplanetary transport system. For this purpose, the landing pad has to ...

1

To augment @Mark's excellent answer let's remember Elon Musks tweet yes. This seems instant from a human perspective, but it really a fast fire, not an explosion. Dragon would have been fine. I can't find a perfect one-liner to quote, but something like An explosive charge is a measured quantity of explosive material, which may either be composed solely ...

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 ...

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