Manual space flight: how common is it?

[Apollonius]

My understanding is that the exact route of space travels are pretty much calculated years before the actual mission takes place, with the people on board merely pushing the right buttons at predefined times. Sometimes they "drive" their ships manually, like when docking with another object, or trying to retreive something.

But how often does it happen, really? To what extent (both time and/or distance traveled)?

Furthermore, could orbit be achieved with today's techology entirely by piloting and navigating independently, like you fly a cessna or drive a car? No pre-calculated trajectories, but radar, GPS, or what ever other kind of feedback is OK. How would it be done? How would they know they have reached orbit?

[Dave]

Manual space flight does not occur other than docking/grappling an object, so far as I know.

Could it be done? Sure. I don't know why you want to put a human in command of a multi billion or trillion dollar spaceship, but you could if you wanted to.

Could you do it yourself? I dunno, try messing around with the Orbiter simulator and find out yourself.

[Sea Skimmer]

Furthermore, could orbit be achieved with today's techology entirely by piloting and navigating independently, like you fly a cessna or drive a car? No pre-calculated trajectories, but radar, GPS, or what ever other kind of feedback is OK. How would it be done? How would they know they have reached orbit?

Once you get above a certain speed your in orbit. Once you get above a certain height, atmospheric drag is low enough that you can maintain that speed for long periods without an engine burn, nothing special about it. This isn’t very hard to figure out, but how you’d actually go about reaching it with all manual control and nothing precalculated would depend on the design of your spacecraft. In any case, the pilot is going to know a fair bit in his head about how his craft works and what angles it needs to reach orbit, anything else is just totally unrealistic.

[RedImperator]

My understanding is that the exact route of space travels are pretty much calculated years before the actual mission takes place, with the people on board merely pushing the right buttons at predefined times. Sometimes they "drive" their ships manually, like when docking with another object, or trying to retreive something.

But how often does it happen, really? To what extent (both time and/or distance traveled)?

Furthermore, could orbit be achieved with today's techology entirely by piloting and navigating independently, like you fly a cessna or drive a car? No pre-calculated trajectories, but radar, GPS, or what ever other kind of feedback is OK. How would it be done? How would they know they have reached orbit?

The problem is fuel. Fuel is budgeted down to the gram on these burns, because every gram of fuel you carry is a gram a payload you left on the ground, and space launches are too expensive as it is to budget tons of extra fuel to account for human error, and at the speeds and distances involved in space travel, even tiny errors can put you in the wrong orbit. It's not like if you overshoot your exit on the interstate or something, where you can just turn around and try again. Space launches are too expensive and have too little margin for error to allow pilots to manually fly their ships in any situation a computer could do it better.

[Winston Blake]

Furthermore, could orbit be achieved with today's techology entirely by piloting and navigating independently, like you fly a cessna or drive a car? No pre-calculated trajectories, but radar, GPS, or what ever other kind of feedback is OK. How would it be done?

Probably a lot like driving a car blindfolded. For example, you know you've got to drive until you get to the McDonalds sign down the road, then you turn left, and then keep driving for 200m to get to the seedy brothel that you frequent, you filthy sleaze you.

So for reaching orbit, you'd burn in one direction for a while, staying 'on target' with your GPS position-attitude-velocity-o-meter, and when your timer goes 'ping', you turn to a new direction and fire your engines in a de-eccentricity-ification burn (WTF is the real term?) until the timer goes 'ping' again and you should be in your planned orbit, surrounded by space hookers.

How would they know they have reached orbit?

GPS-position-attitude-velocity-o-meter.

[Winston Blake]

...and by blindfolded, I of course mean not blindfolded, unless you were blindfolded AND also had a freaky GPS receiver implanted in your brain.

BTW if it wasn't clear, that first burn is the launch, and that 'one direction' would be generally upwards. The second one is when you're in a suborbital trajectory and if you didn't do a second burn you'd crash in like, Siberia, and wolves would gleefully feast upon your mangled flesh.

[Kanastrous]

The most spectacular manual burn I know of, was executed by the crew of Apollo 13 on their way to re-entry at the conclusion of their mission.

And they got it right.

[The Spartan]

The most spectacular manual burn I know of, was executed by the crew of Apollo 13 on their way to re-entry at the conclusion of their mission.

And they got it right.

But it was a nerve-racking event that had they not gotten right, would have killed them.

[Kanastrous]

Well, yes, they were highly motivated to get it right.

[Apollonius]

the seedy brothel that you frequent, you filthy sleaze you.

Oh noes, you uncovered my secret! *pulls hood over head and scrambles away*

GPS-position-attitude-velocity-o-meter.

Does GPS actually work in space, or are you whooshing me? And never mind today, what did they do in the 70s, when there was no GPS? How can you know your speed in space? I imagine that comparing your position to earth landmarks would be too inaccurate.

[Kanastrous]

(a) No, GPS receivers don't function in space, and

(b) Inertial-stellar navigation, using accelerometers and gyroscopes.

[sketerpot]

(a) No, GPS receivers don't function in space, and

(b) Inertial-stellar navigation, using accelerometers and gyroscopes.

You need special GPS receivers, but it is possible to make ones that function in space. Here's an article on it.

[Kanastrous]

That's a really cool new use of the equipment. Thanks!

[MKSheppard]

Furthermore, could orbit be achieved with today's techology entirely by piloting and navigating independently, like you fly a cessna or drive a car?

Takeoff from landing field on turbojet power. Proceed up to Mach 3.4 at 100,000 feet on turbojet power. Switch to ramjet mode, and hit Mach 5 at something like 150,000 feet or higher. Switch to rocket mode; and fly higher and faster with each evolution of designs until you're in orbit.

[Broomstick]

Docking/grappling are the only routine manual-flight of spaceships.

Apollo 13 "proves" it can be done to make navigational changes, but also proved at even with 3 of the best hotshot pilots it's nerve-wracking and chancy at best. And keep in mind, those guys didn't make the burn calculations - the guys back at mission control worked out the details and the guys on board "merely" executed them. Space travel and navigation is not 100% certain as numerous failed interplanetary missions have demonstrated.

[Sea Skimmer]

Furthermore, could orbit be achieved with today's techology entirely by piloting and navigating independently, like you fly a cessna or drive a car?

Takeoff from landing field on turbojet power. Proceed up to Mach 3.4 at 100,000 feet on turbojet power. Switch to ramjet mode, and hit Mach 5 at something like 150,000 feet or higher. Switch to rocket mode; and fly higher and faster with each evolution of designs until you're in orbit.

It’s pretty much impossible to reach orbit by that method without refueling somehow at supersonic speed along the way, or else jettisoning a very large piece of the aircraft (thus the interest in two stage air launched spaceplanes). You just cannot take off with enough fuel and oxidizer to make it work otherwise, nor is subsonic refueling likely to be sufficient. This is why the RamLACE and ScramLACE engines were proposed, to liquefy and store oxygen in mid flight until you exceed your takeoff weight, when already cruising at mach 5-6 and 100,000 feet.

[Sarevok]

I suppose any object with sufficient velocity will escape Earth's gravity.

A better question would be can manual navigation alone lead to useful destinations in orbit like reaching a specific satellite or station ?

[Skylon]

My understanding is that the exact route of space travels are pretty much calculated years before the actual mission takes place, with the people on board merely pushing the right buttons at predefined times. Sometimes they "drive" their ships manually, like when docking with another object, or trying to retreive something.

But how often does it happen, really? To what extent (both time and/or distance traveled)?

Furthermore, could orbit be achieved with today's techology entirely by piloting and navigating independently, like you fly a cessna or drive a car? No pre-calculated trajectories, but radar, GPS, or what ever other kind of feedback is OK. How would it be done? How would they know they have reached orbit?

As noted rendezvous and dockings are the usual case where pilots take manual control of their spacecraft (usually after a series of calculated burns, and they're only "flying by the stick" late in the game).

There have been several cases of manual re-entry (albiet with input from the ground, or computer support). The second shuttle mission ended with a landing with the pilot's hands on the stick, all the way through, from the de-orbit burn, to the call of "wheel's stop", just to make sure it could be done (normally the pilots don't take control of the shuttle during landing until final approach). This is the only time I can think of a manual entry being done intentionally.

A couple of early Soviet flights (Voskhod 2 and Soyuz 1) saw cosmonauts needing to hold their spacecraft at a proper attitude manually through retro-fire due to the failure of automated systems (using the sun as reference, similar to Apollo 13 using Earth as reference). Voskhod 2 ended up way off course, but on Earth with a live crew. Soyuz 1 ended up on course to a backup landing site, but failed for other reasons.

A similar thing happened on the final Mercury flight, however with a landing closer to the rescue carrier than the computer had managed at that point.

[Admiral Valdemar]

It’s pretty much impossible to reach orbit by that method without refueling somehow at supersonic speed along the way, or else jettisoning a very large piece of the aircraft (thus the interest in two stage air launched spaceplanes). You just cannot take off with enough fuel and oxidizer to make it work otherwise, nor is subsonic refueling likely to be sufficient. This is why the RamLACE and ScramLACE engines were proposed, to liquefy and store oxygen in mid flight until you exceed your takeoff weight, when already cruising at mach 5-6 and 100,000 feet.

That's what Skylon and similar SSTO designs are addressing. The SABRE engines for Skylon, if they prove to be able to meet the specs, could offer this capability and reminds me of the RB545 for HOTOL.

I'm hoping such projects eventually prove themselves workable, if not financially for commercial flight, then at least technically for government investment. Of course, there are doubts over air-breathers being able to offer this Holy Grail.

[PeZook]

Actually, the Apollo 13 correction burn was standard procedure. Lovell wrote it way before the flight for precisely this kind of emergency. The main problem was that they couldn't be certain the LM engine would fire again, so they had to time it just right using nothing but their wristwatches.

It always pays to have a good watch with you, wherever you go

Apollo astronauts could also, theoretically, fly their capsules through re-entry completely manually: but it was a last-ditch option, the computer usually did it better.

As for the OP questions:

1) It's absolutely possible to fly to orbit on manual control. It will take you more fuel than automatic flight, the trajectory won't be very precise (in spaceflight, you don't just want to get to orbit: you want to get to a proper orbit so that you can go somewhere, but technially it's just a matter of titling your spacecraft at the right moments so that your velocity vector points to the right direction and is long enough

People on Orbiter can do it quite precisely by eyeballing it, but it's just a sim - it has around a gazillion less factors influencing the spacecraft during ascent.

2) To what extend does it happen today? The Shuttle lands manually (re-enters on automatic, though. The thing is supposedly really unwieldy during re-entry), it docks manually and that's pretty much it. Automatic docking is quite possible, though it works best with sane capsule designs like the Progress.