RCgothic

F9 B5 has now had 19 successes from 19 missions. The success rate based on Bayesian statistics is: P{S} = (n{S}+1)/(n+2) Where: P{S}= Probability of mission success n{S}= Number of successes n = Number of attempts P{S}= 95.2% For falcon 9 as a whole, it's 76 successes from 78, or 96.3% That has to be close to an industry leader surely.

It's not the composition (identical), it's the behaviour. If you've seen the scene in "Passengers" where the gravity turns off and the effect that had on the swimming pool you'll have some idea. Water in zero g is sticky. It forms balls. It clings to things and covers surfaces. There's no buoyancy, so you can't escape by letting yourself float. Which way is out? Then when you do get to the surface it clings and distends around you, refusing to let you go. Found an external handhold to pull yourself out? It'll cling to that too and come with you. It's far too difficult to get out of. In zero g large quantities of water is an extreme drowning hazard. The moon has gravity so it would be far less hazardous to have your swimming pool there.

Pretty sure that much free water in zero gravity would be an extreme hazard. At least some gravity/spin is required at a minimum. Plus it's heavy, a tonne per m3. It's not something you want to be carrying around on a spacecraft unless it serves dual purpose. That said, I've heard that if you had a swimming pool on the moon, humans would be able to leap like dolphins. If you were using hydrolox as power, then that's worth taking to the moon for that alone. You could then condense the products and make use of the water byproduct to create the solar system's best water park!

That's a graph for cotton plant fibres?

I wonder if red components are a colour code for "not for flight", e.g. supports or blanking plugs that need to be removed before the rocket reaches the pad.

Twice the money, eight times as many first stages. I guess the relationship of space expenditure to rockets is cubic.

Wow that's depressing.

4 times now!

They claim 98% efficiency and an exhaust imparted with so much energy it burns blue. But the only available stats are from their own promotional materials and it hasn't had a full-scale test - yet. 365s is 6s better than the best available vacuum engine right now. I can *just* believe that there's 6s to be had out of a monolithic 3D printed combustion chamber, but wow even so.

Sounds like it could be possible damage caused by rough seas yesterday. Seas are calm today, so that's not the reason.

Interestingly, 15,400kg to LEO is over 90% of Falcon 9 FT's nominal payload to LEO (reusable) according to Wikipedia. I remember people saying payload to LEO is a nominal value for comparison that could never actually be used, and that the payload adaptors can't handle it. Wikipedia actually lists the F9 B5 PFA structural limit as less than 11te! I guess payload to LEO isn't so nominal anymore.

According to Reddit, May's launch was 227kg per sat, ~13,670kg total. On this launch it's up to 260kg per sat, 15,400kg total. So the sats are indeed heavier. It may be as sh1pman says, material changes due to burn-up concerns, or they may simply be more capable. May's launch was v0.9 prototypes, whereas this is officially the Starlink-1 mission.

It's been said again and again. SLS/Orion isn't the rocket/spacecraft combo we need. For LEO assembly it's too expensive, flies too infrequently, and has nowhere near enough dwell time with a hydrolox upper stage. For BEO operations it doesn't have enough throw weight to accomplish anything meaningful in a single mission. Which brings us straight back to too expensive, flies too infrequently, and has nowhere near enough dwell time, because the lack of throw weight makes rendezvous a necessary mission requirement. You don't need a big man-rated (and therefore expensive) booster for getting a crew to orbit anymore. Rendezvous is a solved problem. Ares absolutely had the right idea (minus the bonkers srb design). You want a big dumb booster that's payload agnostic, inexpensive, and can fly frequently. 200t to orbit. Then you'd have a range of things you could stick on top of it to suit the mission. It doesn't have to be fancy, or have great BEO performance. That much is handled by the payload. It just needs to get to LEO as cheaply and as often as possible.

Planes accessed by steps from the tarmac often load front and rear as well. Note the twin boarding steps in this photo.

As an experienced flyer and engineer not prone to being unsettled by turbulence, sitting where you can see the wings flexing probably wouldn't be helpful. In severe turbulence that's what gets me the most. I'd suggest an aisle seat in the nose, well forward of the wings.

Ok, I'll bite, using my best Googlefu and an estimate for head length: The average human is 67kg. Average height 1.67m. The cylinder is 1.52m radius. Let's break the body down into 3 regions of roughly uniform mass distribution. Legs are approximately 35% of body mass (21.7kg) and are on average 45% of total height (0.75m). Their average radial position is 1.15m. They contribute 24.9w2 to force. Head and neck is roughly 8% of body weight (5kg). They're about 30cm long. That puts the average radial position bang on the spacecraft axis. It contributes nothing. Trunk and arms is the remainder. 35.3kg and 62cm long. The average radial position is 0.46m from the axis. They contribute 16.4w2 to force. The total force due to centripetal acceleration is therefore 41.3w2. 1g on 67kg is 657N = 41.3w2 15.9 = w2 w = 4 radians per second = 94rpm. Incidentally your toes would be experiencing approx 2.47g.

We have rockets that can put: Dragon, 13ft Orion, 16ft Skylab, 23ft. When starship is operational, it will be 30ft. Why exactly are you limiting to 10ft? Even so, simulating 1g with roll would be horrific. You'd be much better off spinning up in pitch or yaw for a long cylinder. Better still, tethering two craft together and spinning around the mutual barycentre. The centre of mass of a human male is approx 0.56 the ratio of height. For a 6ft male, the centre of mass would be within 2ft of the roll axis and the top of the head would be in negative g. I have no idea how you sum that lot to 1g total, but I suspect it requires a rotation *much* faster than the 24.4 RPM Codraroll calculated above.

Apollo's command module had a pressurised volume of 10.4m3. Crew dragon has a pressurised volume of 9.3m3. That's only a 10% difference. With a proper service module it could get to the moon and back.

I'm a pretty prodigious Trekkie and I've never heard "troop transport" suggested as an original purpose for the galaxy class before. It was purpose built as a deep space exploration cruiser. It's large size makes it pretty good at pretty much any role.

The three centre engines can gimbal through the centre of mass. So with one firing through the centre of mass it would not experience a rotational moment. It may have to touch down at a couple of degrees lean however. Or the engine or thrusters could kick it over into vertical in the second before touchdown (deliberate rotation).

Actually we can handle 6g of freefall just fine because everything is accelerating together the different parts of the ship aren't under relative strain. If you jumped in at orbital velocity you could break free at 1g of propulsive acceleration in the prograde direction just fine. The point was more that a ship with only 5g acceleration available would be in a great deal of trouble if it jumped in at zero relative velocity next to a star with a local gravity of 6g.

If the payload is a methalox third stage performing a one way delivery to the lunar surface, that's in the region of 380t landed.

The sun has a radius of about 2.3 light seconds, so it depends a little on whether you're talking distance from the centre or distance from the surface. 5 light seconds from the centre is 2.7 light seconds from the surface for instance. Simplistically, intensity follows an inverse square relationship with distance. Earth is about 8 light minutes from the sun, so 2.7 light seconds is 178 times closer or 31.7 thousand times more intense. This is complicated by the sun no longer being a point source at that distance, so it could well be a great deal more. I could just about imagine a spacecraft with a well designed insulated great shield surviving that. However. At 5 light seconds from the centre of the sun the force on every kg is approx 59N, or 6g. So a 1-5g spaceship wouldn't survive for long regardless of its heat shield.

So we've discussed a lot about how orbital refuelling allows starship to take some pretty incredible payloads beyond LEO. 150t to TLI is over three times Saturn's previous record. I've just seen it suggested that orbital transhipment of cargo could allow a single starship to take 750t through TLI on a full propellant load. That's insane!

I struggle to see how an SLS suited to recreate an Apollo style mission would be less suited to any task than the SLS we have. The ability to comanifest substantial payloads and reach lower lunar orbits is a significant advantage to any job Orion and SLS could perform.