If you boosted a business jet to 100,000 feet what happens? Can it come back down intact?

Just curious. The max ceiling on business jets is around 50,000 feet. If you could somehow use a detachable rocket booster and kick it up it to 100,000 feet, release the booster and let it go (the pilots and passengers have oxygen masks) is that environment survivable? Does everyone explode? Can the engines and airplane even operate at that altitude for a higher end business class jet?

The engines probably wouldn’t be able to run at 100,000 feet, but I see no reason why you couldn’t glide down to a lower altitude and restart them.

I’d be more concerned about stresses on the airframe from your hypothetical rocket booster.

Its engine would cut out and it would have little/no ability to orient itself. As it came back down, its engines would start working and the effectiveness of its control surfaces would increase.

The scenario that I can see resulting in a ground-actuated deceleration is if its nose points down too much and the combination of its control surfaces & structural strength don’t allow it to pull up quickly enough without breaking itself apart. That wouldn’t be a problem with a fighter or attack plane but it might be with a business jet.

ETA: Oh, depending on the angle at which it comes back down and the velocity reached with the booster, heat damage might be a problem.

Well, without spacesuits I think they’d be SOL. At least per NASA:


I’d be kind of concerned about how much speed you’d pick up as you fell from that height before you ran into a noticeable amount of air. That’s not as high as Baumgartner’s jump, so you might not break the sound barrier in a vehicle that isn’t rated for it.

Jet engines breathe in oxygen and combine it with fuel to make thrust. At 100,000 feet, there’s effectively no air, so no oxygen, and the engines quit long before you get there. The control surfaces also rely on air, as do the wings, so you have no lift and no control. There’s no way to compensate for even the tiniest of forces acting on it, so it’s going to end up tumbling wildly out of control.

When it finally does come back down to where there’s enough air to get some control over it, it’s going to be tumbling wildly and will be going way too fast. I’m not an aeronautical engineer, but I suspect that you will probably rip the wings off before you get a chance to get it into a recoverable attitude.

Your pilots and passengers will also basically need full-blown space suits. An oxygen mask ain’t gonna cut it. They are going to need fully pressurized suits of some sort.

In 1983, there was a TV movie featuring Lee Majors with a plot about a plane that ended up in space.

See Starflight: The Plane That Couldn’t Land

Wiki page

I remember that one; quite possibly the stupidest movie I have ever seen.

That’s pretty much the whole story.

The X-15 had a hybrid control system with aerodynamic controls for ~100,000 feet and below and cold-gas reaction thrusters for attitude control at higher altitudes. To be sure it went a lot higher: up to 300,000 feet for round numbers. But even much lower they found they needed the RCS to keep the airplane aligned with where it was going. The aerodynamic restoration forces that normally create stability just weren’t strong enough to prevent tumbling.

If we added space suits and reaction controls to our rocket-boosted bizjet we could at least aim it at very high altitude. But once the jet engines quit on the way up you’re out of normal electricity and normal hydraulic power. Not good.

All jets have battery backup systems which provide limited instruments & avionics. This covers for the dual electrical or dual engine failure scenario at conventional altitudes. But from the pilot’s POV flying on that stuff is a pretty big emergency in its own right. Trying to do something this out of the ordinary on backup instruments would be silly. So we also need to add some additional auxiliary AC power source that’s not dependent on atmosphere. The Space Shuttle used a turbo-generator set driven by exothermically decomposing hydrazine over a catalyst bed. We might be able to get one of those from NASA surplus.

Once you get far enough into the very thin atmosphere you have the problem the standard instruments don’t really give the crew the info they need: which way am I pointed vs. which way am I traveling? So we need some additional sensors and instruments to compute and display our 3D velocity vector. Typically that info is available inside the avionics but isn’t displayed directly to the pilots. As well, we’ll probably generate some values that would be out of bounds in normal flight. Have to make sure the avionics software doesn’t crash or reset when it generates these apparently crazy values.

Some bizjets have hydraulic flight controls. No hydraulics, no aerodynamic steering. Those types will have a backup power source for the hydraulics, but those are normally driven by sticking a propeller out into the slipstream. Which isn’t going to be effective at very high altitude. So they’re going to be in a world of hurt in the transition area where the aerodynamics start to matter but they haven’t restarted the engines yet. So for aircraft with hydraulic flight controls we need an aux power source for them that doesn’t depend on the atmosphere too. More Space Shuttle surplus here too.

Other bizjets have simple mechanical cable-operated controls. All else equal those would be a better choice for this silly mission.

The instant you said that, I knew that I just had to see it. I don’t know why I do this to myself. :frowning:

If Chuck Yeager couldn’t do it in an F-104, I think a basic business jet wouldn’t fare much better.

Here’s Yeager’s description.

Sorta-related anecdote.

The F-16 was certified to fly to 50,000 ft. I’ve been there, briefly. Once. There wasn’t much engine power left and it maneuvered better than an airliner, but not a lot. i.e. it wallowed pitifully by fighter standards. There just wasn’t much air to work with for either engine thrust or flight control power. You were pretty squeezed between high Mach & low indicated airspeed. And this in an airplane able to do 9Gs and Mach 1.8 down low where it had the thrust to do that stuff. We also flew with a pressure breathing oxygen system that would keep us conscious a bit above 50,000 even unpressurized. As noted above, bad things happen physiologically real quick much above that altitude.

While I was in that unit another pilot at another base found a novel way to kill himself and wreck an airplane. Down at about 40,000 feet he went to full power and accelerated to a little over Mach 1.0 in a shallow dive. Then he started a zoom climb. Bad idea.

Passing about 55,000 going uphill the engine quit. The emergency hydraulic and electrical generator kicked in as designed. Passing about 60,000 the cockpit finished losing pressure. It’s not a very big volume, so it happens fast. He passed out and started taking major physiological damage. About 65,000 the aircraft apogee’d & started downhill. A bit later it hit the Gulf of Mexico doing about Mach 1.2 going more or less straight down.

They found the wreckage and some chunks of the pilot. There was a primitive flight data recorder attached to the seat & they recovered that. That info plus radar tracks from the AF range radar was all they had to go on to assemble the accident sequence.

Bottom line: a highly capable aircraft and crew that works totally OK at 50,000 totally turned into a pumpkin just a bit higher.

Since you’re going to the trouble of adding a rocket booster to the aircraft you might as well make it a steerable system and give the passengers and crew spacesuits, strengthen the airframe and control surfaces, and one more time ask “What are we doing this for?”.

It starred Lee Majors. Does that help?

On the contrary; it will only make the self-abuse that much more gratifying.

This is what I was going to post.

Because SpaceShip Two http://www.virgingalactic.com/ is funny looking & the OP wants to be first instead? After all, look at the guy’s name. It only makes sense. :slight_smile:

Agreed the OP is just silly. But fun silly, not stupid silly.

The engines will not run at 100,000’ and without engines, there is no pressurization… so you will need spacesuits.

I don’t have a problem with either one. The rest of what it takes to make this work could be enjoyable. Aside from the regulatory spacesuits what’s missing is the way to maintain a reasonable attitude for re-entry. Maybe all it needs is a drogue chute.

Excellent post.

Suppose you took care of the life support problem, and used a jet with manual controls. What would happen if you tried to take it to 100,000 feet? Obviously the controls would be ineffective and the plane wouldn’t necessarily stay pointed the right way. What happens as it comes back down? The air is going to gradually get thicker until the controls start to work again. Is there any hope of regaining control and stability at that point?

Part of what got Yeager in the NF-104 was that the elevator was in the full nose-up position when the engine shut down, and without power it stayed there. If you use a jet with manual controls, does it help the situation at all?