# Tag Info

57

The purpose of Starship is not merely to put satellites into orbit for cheap. If that were its purpose then you'd be correct; it's way overbuilt for that. Starship wasn't created to put satellites into orbit though, it was created to construct a self-sustaining city on Mars. Achieving that goal will likely require lifting hundreds of megatons of mass to ...

56

By design that will never happen. There are always enough return seats for the crew. This is exactly why the whole crew of one of the visiting vehicles gets in it whenever it undocks, even when it is only being moved from one docking port of the station to another the crews retreat to their vehicles in fire / leak / toxic atmosphere emergencies the crews ...

29

There are a few reasons: The most obvious but easier to overcome is that the Starship is new. They haven't had the time to perfect everything. For example, the Raptor engines use two separate turbopumps, one for liquid oxygen and one for methane. This improves efficiency but it makes the engines far more complex. The Raptor is the first engine of its kind to ...

27

What would happen if there was a freak accident in which that the ISS needed to be evacuated and there was ONLY one space craft available? Carrying that to an even greater extreme, what would happen if there was a freak accident in which the ISS needed to be evacuated and no space craft was available? For example, suppose two human-qualified vehicles are ...

24

The size is mostly based around missions to Mars as opposed to satellite launch. Where satellite launch is almost a side mission. Refueling missions for Mars missions will require 7 launches (1 payload, 6 fueling missions) for each vehicle going to Mars. Lunar missions will need 2 or more (not clear this number is settled) refueling launches. As noted in the ...

16

Your premises are not really correct. During the return trip from Mars or Moon, SpaceX starship can refuel it's propellant tanks before reentry. The only way to refuel during the return trip would be for a second Starship to make the same journey from start to finish, alongside the first, at enormous expense. Reentring the Earth's atmosphere with high ...

12

The reason why SpaceX exists is to Make humanity a multiplanetary species. https://www.spacex.com/human-spaceflight/mars/index.html And unlike the mission statements of other companies which are often just sound bites, this really is what SpaceX is all about and why they do things the way they do. For most companies the primary goal is to make money. But for ...

11

The static fire is just to make sure the engine will start, not to simulate the entire flight profile. The problem isn't the engines themselves - they work just fine on ascent. The problem is that the rapid transition from horizontal to vertical creates all kinds of interesting stresses and flow dynamics in the tanks and the plumbing, leading to ...

10

The experience of landing a booster for SpaceX is actually more relevant directly to the Super Heavy booster, which has yet to fly. (BN1 was built as a pathfinder, then disassembled. BN2 is under construction as of Apr 2021). Falcon 9 lands its first stage, which is analogous to Super Heavy. However, it does not land its upper stage, which is more similar ...

8

Most remotely controlled spacecraft and rovers do not use text-based commands. Instead, each command has a unique identifier, a command-specific data structure that contains data specific to that command, and data (e.g. checksums) that confirm the command and data are valid. All of the data are binary rather than text-based. The Mars rovers use a sequenced ...

8

Building a sustainable settlement on Mars will need hundreds of flights. Building tens of Starships and reusing them vs. building hundreds of Starships and throwing them away, is going to be much cheaper. Given the fact that the Starship lunar edition lacks ailerons and therefore cannot reenter Earth's atmosphere (and survive, that is), a one-way-only ...

8

SpaceX has both vertical and horizontal Raptor test stands, to test operation in both orientations. The relight issues could come down to engine performance/quality -- It is a new engine entering mass production, so they have growing pains to work out. This is why they are A) building so many and B) testing them in flight. The relight issues could also come ...

7

Is Starship planned to fly directly to the ISS without first stage? Is it expected to deliver astronauts to the ISS Crew-Dragon-style, but without the 2nd stage; that is, "FSTO"? No. Starship will be launched on top of Super Heavy. There is no plans for a SSTO Starship on Earth to carry crew/cargo to orbit. Is it even possible? Tweet. You would ...

5

Starship cannot hit the ground at 11 km/s. Those speeds are only attainable in a vacuum. As the ship reenters, it slows down due to the atmosphere, and it continues to slow down pretty much the entire way to the ground. A falling object will have a terminal velocity of about 100-200km/h depending on its shape. Starships empty mass is a lot less than a Boeing ...

5

Nobody was killed in the SN10 explosion. The explosion was on the landing pad in the middle of a 5-mile exclusion zone. Nobody was within 5 miles of this explosion.

5

There WAS a different concept for returning folks from orbit in emergencies that was considered, called MOOSE, but it never got out of the planning stages.

5

Assuming this simulation is correct, and I have no reason to doubt that it is, there is in fact true 6 degrees of freedom of movement possible. I do recall that at least one of the axis has less control, but I can't find the news report that states how the manual control felt according to the astronauts...

4

Another factor: By making the price per pound to orbit a lot cheaper you can make satellites cheaper, also. In the space business you bend over backwards to shave off every bit of weight you can because it's so expensive to lift it. All that weight-shaving costs money, lots of it. Lets call the per-launch price $5 million--that cuts the price per pound ... 4 Starship will not be launching many satellites at \$2 million a launch. I don't think there will ever be enough of a market to justify that. Let's just assume that Starship reliability can get to the point where the cost to launch will be \\$2 million/ launch, something on the order of 1000 launches per Starship. The launch market would have to be 1000 ...

4

Reusability is important because of the vast number of tanker Starships that will need to be flown into orbit. It is essential that these tankers can be used over and over again to ensure sufficient propellent is put into orbit to supply the cargo ships and the crewed ships that will be traveling to the Moon and to Mars. And to ensure this happens cheaply. ...

4

For shuttle which used a MIL-STD-1553 bus system for its flight critical functions, a command consisted of some header information (mostly used for validation), the address of the bus terminal unit, card, and channel on the 1553 bus to which the command was to be sent, and a mask to set the desired bits. The commands were made up of one or more 48 bit words. ...

4

If you look at the webcasts you'll see that they are extended while in free fall (before re-entry) and you can kind of see them bounce and lock into place with a jolt. I believe they are hydraulically actuated and do not rely on aerodynamic force to stay extended. I do not know about your second question however. See the OTV5 / X-37B launch from 2017 just ...

4

As of September 2020, the plan was for Starship to install three sea-level Raptors and three vacuum Raptors. The vacuum engines will likely be used by themselves for the trans-Martian burn from Earth orbit, and the return burn from Mars to Earth, as efficiency matters much more than total thrust for those maneuvers. Mars's atmosphere is thin enough that ...

4

SpaceX chose to use RP-1 because the development path for a good RP1 engine was a full decade shorter! Plus many other factors favoring KeroLox for launch from Earth surface, for example the very high energy density of RP-1 allows smaller tankage, which is a great advantage when flying through the atmosphere. The Excellent thrust density of RP-1 also allows ...

3

Is it expected to deliver astronauts to the ISS Crew-Dragon-style, but without the 2nd stage; that is, "FSTO"? (as opposed to SSTO) Starship cannot get to orbit in any meaningful way without Super Heavy. Theoretically, it would be possible to get to LEO without any payload and by removing all recovery hardware, the body flaps, the landing legs, ...

3

Ideal required defining the metrics you are using for idealness. From the sound of it, you're thinking about thermal concerns. Obviously reaching roughly 0 velocity in the ECEF frame(0 groundspeed) before reentry will yield the lowest heating. But it has other consequences. The most obvious is that you have to expend fuel combating gravity. The longer ...

2

While Mike's answer is very well researched and written. I disagree with its challenges (though I don't disagree with his conclusions). The biggest challenges that SpaceX will need to solve in my opinion are. 1. Re-entry heat shielding and Earth landings. It is still working on mastering the landing flip without losing fuel flow. But it also has to show that ...

2

I think it is because SpaceX is maxing out the performance on the Falcon 9. 60 satellites at 227 kg each (Spaceflight Now - SpaceX releases new details on Starlink satellite design) is a grand total of 13,620 kg (not including the supporting structure they are stacked on). NASA Launch Services Program-Launch Vehicle Performance Website gives the capability ...

2

Each thruster will have a thrust vector. That can be resolved into torque and translation depending on the CM. If you have six thrusters you should be able to get all six degrees of freedom. If you want one pure degree of freedom you have to solve a set of simultaneous equations, which is not hard. If there is a degeneracy in the system you may not be ...

1

The key thing is, Starship is really not comparable with STS in terms of reusability. Or with anything existing so far, actually. The shuttle wasn't really reusable, it was refurbishable, but that was a huge cost and turnaround was several months at best. More importantly, the main tank was not reusable, and refurbishing SRBs was actually more costly than ...

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