Posted on 06/27/2019 9:59:11 PM PDT by BenLurkin
Elon Musk, no stranger to outlandish pledges, just teased around-the-world flights aboard one of his rockets.
The chief executive of Tesla Inc. TSLA, +1.63%and Space Exploration Technologies Corp. was tweeting about SpaceX’s latest mission when he veered toward the stuff of sci-fi.
Earth-to-earth rocket flights could carry about 1,000 people. Alas, all seats would be coach, and there would be no toilets, but on the plus side most trips would take only 15 to 20 minutes, Musk tweeted.
It would be “unwise” to let passengers move about during the flights, likening the experience to Disney’sfamed Space Mountain roller-coaster ride:
(Excerpt) Read more at marketwatch.com ...
Musk is a barrel of fun. He has had some rad plans for LA too.
That would be handy at times, but during a vacation, I want to soak up some time. I don’t mind a reasonable wait from start to finish. If someone needed a transport due to medical emergency, the whiz-bang method would be appropriate.
The way the world is going these days, I’m not sure there are that many places I’d be excited enough to go to such that I’d board a rocket to do it.
Sure would make the flight US -> India a whole lot more bearable. Right now, the best you can do, the shortest version of that trip, is JFK - Delhi, at about 14 hours.
There's nothing really science-fictiony about this. This can be done with his BFR rocket, now under development/testing, using probably the second stage only. Spacex would need to build launch/landing/maintenance facilities at each destination, but that's about it.
I don't know if the economics would support it though. If it takes 1000 passengers to be profitable, that's a few 787s worth of passengers at a time. Probably only New York, LA, San Fran, London, Tokyo, Beijing, Hong Kong, and a couple of Indian cities may be profitable.
I don’t understand the part about 1,000 people. He’s talking about the current Democrat presidential candidate field?
I’d like to see Musk with Google or Apple level money. His own of course.
We’d have bases on Alpha Centuri in a decade.
How would you vet who can handle a ballistic trajectory with 4-5g’s on re-entry? It’s too impractical — if you vetted a million people to ride, and half got Clearance, that pool of 500K maybe pays 10K for the trip each, but how many use BFR weekly?
If that’s even 10k — doubtful — that’s only 10 flights a week, so you’re not even scheduling daily NY-Tokyo.
So if you’re not daily, then Mr. Saito is taking the JapanAir polar route non-stop instead.
It takes 88 minutes for low Earth orbit. So 44 minutes to get to the opposite side of Earth. Any faster means you could go into another orbit around the sun. The Soviets actually did that with a probe meant for the moon. They renamed it ‘the dream’ and it now is in an orbit between Earth and Mars.
By my calculations, going half-way around the world in 20 minutes would require accelerating at ~11 g’s for 10 minutes, and then decelerating at ~11 g’s for ten minutes.
Not gonna get many takers (or survivors).
I think the most the human body can stand is around 9gs. There may be a few guys who can handle 10.....but not many.
And that's usually with compression suits, special breathing techniques, training, etc.
Would like to see the estimated G forces due to acceleration/deceleration. Would it be too much for the ordinary passenger?
11+ g’s, average, continuous for 20 minutes.
I’m off by a factor of two - acceleration would “only” be ~6 g’s.
Maximum hop range is 6000 NM.
“10 minutes acceleration... 10 minutes deceleration”
That’s not how rockets work. An eight minute burn at >1g to 3g’s will take the rocket to orbit (~two minutes for first stage, six minutes for second stage). For a suborbital flight, it will be less then that. Upon descent, re-entry into the atmosphere will provide most of the deceleration, then a landing burn for soft landing.
To make it half-way around the world in under 20 mins, per Musk’s claim, that’s the way the rocket would have to work.
All suborbital flight has less Delta V than orbital flight. Again, you don’t know how rockets work.
It’s got nothing to do with how rockets work.
It’s simple physics/math.
“D = one-half acceleration times ‘time squared’”.
Constraining distance and time leaves only acceleration as a variable.
Try computing it yourself and see what you get.
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