Talk:Sub-orbital spaceflight
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[edit] I'm confused...
So any vehicle that travels higher than 100 km yet slower than orbital speed is said to be in Sub-orbital spaceflight.
I don't understand why it is slower than orbital speed. According to the definition of the Karman line, shouldn't it be faster ? In fact, are suborbital flights such as those performed by SpaceShipOne slower or faster than orbital speed ? --Scroteau96 21:28, 25 February 2007 (UTC)
Suborbital flights are almost always slower than orbital speed. SpaceShipOne was much slower than orbital speed. If you can achieve orbital speed (which is very expensive), then you might as well inject into orbit, otherwise you have wasted a lot of money. Charles 16:09, 25 March 2007 (UTC) The only known cases of suborbital flights exceeding orbital velocities were mission failures, e.g. Pioneer-1. Nobody intentionally flies an orbital speed suborbital trajectory (i.e. nobody has money to burn).Charles 16:20, 25 March 2007 (UTC)
- Has anyone done the math to show that the successful lunar impactor missions weren't on sub-orbital trajectories? Intuitively, an object impacting the face of the moon following a direct tracjectory had little angular velocity.... Sdsds 20:47, 25 March 2007 (UTC)
Earth escape missions do not fit the generally accepted defintion of suborbital. I think we are splitting hairs here Charles 03:05, 26 March 2007 (UTC)
- You are right -- we're splitting hairs. Even so, a lunar impact doesn't imply an Earth escape. What matters is that this article is a great opportunity to explain a bit of orbital mechanics, and it isn't clear the article does that very well yet, given that readers describe themselves as "confused". Sdsds 03:29, 26 March 2007 (UTC)
- Fair enough. Over the weekend I will try to write a few words on parabolic trajectories versus elliptical orbits, linking to other content on Wikipedia which covers it in more detail.Charles 13:33, 30 March 2007 (UTC)
[edit] The definition
- So which is it? Suborbital Spaceflight or suborbital flight? The dictionary definition of suborbital says it's anything that does not complete an orbit around the world. This would include all regular planes which are very much suborbital. Surely it should be suborbital spaceflight only and use of the other term should be demoted to 'often mistakenly called' status? John 13:33, 30 March 2007 (UTC)
- You could be on a suborbital trajectory and not be in space though; anything above about 35 km is in very thin air, and momentum dominates.WolfKeeper (talk) 01:25, 30 November 2007 (UTC)
- The difference between suborbital and ordinary flight is largely arbitrary. The government bureaucrats in the USA haggled over it in a jurisdiction fight and came up with a definition that states that something is a suborbital flight if the thrust/weight ratio of the aircraft is greater than one over more than half the powered portion; at least something like that last time I checked.WolfKeeper (talk) 01:25, 30 November 2007 (UTC)
[edit] Flight duration
I restored some text mentioning the duration of the Pioneer 1 sub-orbital flight (43 hours). If you can find a real-world (not theory) example with a longer duration, please use it instead. (On the theory side: if a flight exits the Hill sphere, can we agree it would be non-orbital even if tangential velocity were zero?) Sdsds 15:35, 12 March 2007 (UTC)
[edit] Why were Categories removed?
Why did User:Ksyrie remove lots of categories on 19 March 2007. What was wrong with them? Charles 16:14, 25 March 2007 (UTC)
[edit] Suborbital as in electron orbits?
Suborbital redirects here... will move as soon as I find the right article. W1k13rh3nry 23:47, 24 April 2007 (UTC)
- ah... never mind. W1k13rh3nry 23:48, 24 April 2007 (UTC)
[edit] I'm confused too...
This article says that flights in low Earth orbit "attain orbit but deorbit after less than one full orbital period," but the article on orbital spaceflight defines orbital spaceflight as "a spaceflight in which a spacecraft is placed on a trajectory where it could remain in space for at least one orbit," and then lists low Earth orbit as an orbit area. Does this mean that a spacecraft in low Earth orbit deorbits before completing the circle, but remains in outer space for the full circle? Not going in a full circle but going in a full circle doesn't make any sense. Someone the Person 00:07, 15 November 2007 (UTC)
- there's a difference between a trajectory that would do an orbit, and a trajectory that wouldn't. There's also a difference between being on a trajectory that is orbital and completing it, to being on an orbital trajectory, but doing retrorocket firing that reenters you before you've actually completed an orbit.WolfKeeper 06:57, 15 November 2007 (UTC)
