41 votes

How can Yuri Gagarin's Vostok 1 flight be considered to have been orbital, since he did not go all the way around Earth?

From Wikipedia's article on Vostok 1: Path of Gagarin's complete orbit; the landing point is west of the takeoff point because of the eastward rotation of the Earth. The flight was at ...
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41 votes
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Why does Blue Origin claim Virgin Galactic's spaceplane doesn’t have an escape system whereas Virgin Galactic's passengers are wearing parachutes?

First of all, it should be clear that this infographic is by no means objective; it's designed to put SS2 in the worst possible light, and New Shepard in the best. That said, an "escape system&...
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31 votes
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Is 678 km the new altitude record for a rocket shot "straight up" (vertical launch)?

New Horizons went into Earth parking orbit first, so it doesn't count. For a suborbital direct ascent trajectory, some early lunar probes (USSR's Luna-1 for example) would hold this record. Otherwise, ...
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29 votes
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How can Yuri Gagarin's Vostok 1 flight be considered to have been orbital, since he did not go all the way around Earth?

Using the times of injection and retrofire in this diagram: and the orbit information from NASA, I get that Yuri did about 272° to 273° of a 360° orbit. So about 3/4ths of an orbit. I am not ...
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29 votes
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What is the highest possible altitude of a sub-orbital flight?

Hill sphere is the radius at which gravity of the body (a planet) becomes too weak to pull an object back in, and the object enters a solar orbit. In case of Earth, that is 1.5 million km. In reality ...
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  • 52.4k
23 votes

How can Yuri Gagarin's Vostok 1 flight be considered to have been orbital, since he did not go all the way around Earth?

So he landed 17 degrees west of the launch site. Sure sounds like a (long) sub-orbital flight. You are looking at the wrong parameter. The Earth rotated underneath the orbiting spacecraft during the ...
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  • 63.1k
22 votes
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Do you need a heat shield to enter the atmosphere from non-orbital speeds?

I'm going to make some educated guesses and grossly oversimplify the problem: First, we'll ignore the change in gravitational acceleration over the 200km fall (it's only a 5% difference, so who cares)...
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  • 7,078
15 votes
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Why does Blue Origin land the crew capsule separate from the booster?

It would be extremely unstable. There are 2 things that weight a lot on an empty rocket, the capsule and the engine. With the two of them on opposite sides, the rocket would become extremely unstable. ...
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  • 118k
15 votes

Is 678 km the new altitude record for a rocket shot "straight up" (vertical launch)?

Not sure if this counts, but New Horizons was launched directly into an escape trajectory and did not enter orbit. It made it to Pluto and beyond. From Wikipedia: New Horizons was launched from ...
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  • 1,136
15 votes

Could the SpaceShipOne fly again?

There is absolutely no reason to ever even conceive of flying it again. It was retired because it successfully did the sole task it was designed to do. SpaceShipOne was unsafe1, barely met its ...
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14 votes
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Did Soviets/Russians perform any crewed (intentionally) suborbital flights?

There were only four manned Russian programs: Vostok No suborbital flights were made. See Voskhod No suborbital flights were made. See Soyuz There was a two suborbital mission: a failed Soyuz ...
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10 votes
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What altitude would an ocean crossing sub-orbital flight need to reach?

The altitudes are not what I would call ridiculous. Though you seem prone to using unjustified superlatives in your questions. The optimum, i.e. minimum injection velocity sub-orbit was provided by ...
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10 votes
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Falcon 9 maximum point-to-point landing range

I agree with @OuNelson Mangela on the 4,000km figure. I got 4,052km on flightclub.io, but it was a bit of a struggle. I had to glide quite a bit between entry and landing burns to bleed off velocity ...
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10 votes

Is there any kind of research on *sub*-orbital rendezvous-ing with a space tug outside the atmosphere?

I can't find anything on this online. It would seem to be a useful technique as it would lower the delta-v for the vehicle that lifts the payload from the ground to the rendezvous point relative to ...
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9 votes
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What distinguishes a sounding rocket from a suborbital flight?

If the sounding rockets go past the Kármán line at 100 kilometres (62 mi) above the mean sea-level that's now officially the edge of space since the Outer Space Treaty sort of ratified that, there is ...
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9 votes
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Did the crew of Soyuz MS-10 pass the Karman Line?

No From Ars Technica, the failure came around the T+2:00 mark, which would have been close to when staging happens What we know is that at about two minutes, there was some sort of failure with the ...
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  • 6,610
9 votes

Could the SpaceShipOne fly again?

SpaceShipOne was retired so quickly because it was a prototype. One of the key lessons-learned over the last seventy-plus years was that the waterfall model does not work when applied to creating ...
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  • 63.1k
9 votes

Why does Blue Origin claim Virgin Galactic's spaceplane doesn’t have an escape system whereas Virgin Galactic's passengers are wearing parachutes?

Because this isn't an informational infographic. This is an ad. And, as such, it is deliberately skewed to paint the advertised product in the best possible light, while disparaging the competing ...
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8 votes
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What was the point of the Redstone rocket when there was the X-15 rocketplane?

The goal of Project Mercury as stated in 1958 was to put a man into orbit safely. In order to do that, NASA wanted to send animals, first. The Russians had done exactly that, and NASA preferred using ...
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  • 6,760
8 votes

What is the highest possible altitude of a sub-orbital flight?

Impossible to say without heavy modelling. If the Earth was a solitary, stationary object, then the highest possible altitude of a sub-orbital flight would be nigh-infinite, since it would always be ...
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7 votes

What distinguishes a sounding rocket from a suborbital flight?

Some sounding rockets are sub-orbital. Sub-orbital merely means going into space with less than orbital velocity. Going into space: That's a bit arbitrary, but a person who goes 50 miles or higher (~...
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7 votes
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Would a point-to-point suborbital spaceflight have a "negative" perigee?

A minimum energy ellipse between departure and destination corners of a Lambert space triangle is described on page 65 of the 1993 edition of Prussing and Conway's Orbital Mechanics textbook. In ...
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  • 15.1k
7 votes

What use could be getting to space just for a bit?

There can be many reasons: Test of technology Doing in-situ measurements in the mesosphere, which is too high for balloons, too low for satellites Performing microgravity experiments where parabolic ...
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  • 11.1k
7 votes

How to calculate apoapsis of sub-orbital trajectory?

First calculate the semi-major axis $a$ where $\mu$ is standard gravitational parameter of the planet that in orbit around: $$E=\frac{v^2}{2}-\frac{\mu}{r}$$ $$a = -\frac{\mu}{2E}$$ Then with the ...
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  • 261
7 votes
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What is the delta-V equivalent to cross the Kármán line in vertical (suborbital) flight?

We can get an best-case estimate by just solving the equations of motion: $$s = \frac{1}{2}(u + v)t $$ Where $$t = \frac{v-u}{a}$$ Since we want $v = 0ms^{-1}$ at $s = 100,000m$, we get: $$s = \...
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7 votes
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How many hours long is Earth's longest possible sub-orbital flight?

How many hours long is Earth's longest possible sub-orbital flight? "Orbit", and thus "orbital" and "sub-orbital" is another one of those words like "rocket" whose definition alters significantly ...
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6 votes

Why does Blue Origin land the crew capsule separate from the booster?

There's 2 major reasons: safety and practicality Safety: If you look at the history of booster landings it is not a proven technology, the reliability is not good enough for safety. Don't get me ...
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  • 18.7k
6 votes

Do you need a heat shield to enter the atmosphere from non-orbital speeds?

The Falcon 9 rocket first stage leaves the atmosphere, reaches about 140 KM max altitude, and then reenters without a heat shield. So no, heat shields are not strictly necessary for sub-orbital ...
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  • 6,553
6 votes
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Why didn't Project Mercury advance to an orbital flight on their second mission?

You have to remember that during Project Mercury, not only crewed spaceflight was in its infancy, but spaceflight itself was. The Mercury-Redstone rocket could not achieve orbit, it wasn't powerful ...
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  • 6,760
6 votes

What is the highest possible altitude of a sub-orbital flight?

Are you asking theoretically, or in the real world? Theoretically, there is no upper limit, because gravity extends forever. Gravity does get weaker the farther you travel, but it never reaches zero. &...
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