Orbital with just jets?

[dharak1]

So I was trying to circumnavigate Kerbin with a super fast jet that got launched assisted with SRBs. I was around 13 minutes into the flight and halfway around Kerbin when I hit 2.2 km/s and the camera switched to orbital. I looked at the map and my apoapsis was 84 Km and my periapsis was 27 Km I got a couple screenshots of the plane and the map. It's not even an intake spam plane. Only two intakes.

Map screen

Plane

[bsalis]

Well, strictly speaking if you used SRBs then it is not "just jets".

However, I believe it is possible with only jets. If you store enough IntakeAir (yes - the intakes do store a little of it) to run the jets a little at Ap to lift the Pe above 68Km.

[dharak1]

The SRBs were only used to get me up higher faster so I didn't have to climb as long. I landed with 250 liters in the tank so I could use a bare plane if I wanted to.

[Kerbart]

Orbit? Your orbit will always contain the point where you stopped your final burn. Unless you're using a RAPIER that will be in the atmosphere, so it can never by a sustainable orbit. You'll have to bring a rocket (even if it's just a handful of separatrons) to circularize.

[MiniMatt]

I suppose technically, being in orbit around an atmospheric body does not necessarily imply or require being "in space". Orbit requires covering an arc compatible with the radius of the planet in a time frame compatible with the gravitational constant and mass of said planet.

Ie. one can orbit the Earth whilst staying just above the surface by maintaining a velocity of ~8km/s - maintaining that velocity in the face of drag's oppositional force will naturally require the constant application of energy but I think it's still "in orbit".

[Silverchain]

Yes. You can orbit in atmosphere if you're prepared to compensate for drag. Satellites like the ISS orbit in the upper reaches of the Earth's atmosphere, which doesn't cut off sharply like Kerbin's, and experience a small but not negligible drag.

As bsalis mentioned, it's possible to use a trick to obtain true orbit outside Kerbin's sharply defined atmosphere by storing the resource intakeair in a closed intake and then using it to briefly fuel a jet in space.

[Kasuha]

You can get orbital (Pe > 70 km) with just jets (meaning no other engines) without intake air storing if you abuse the momentum conservation law a bit.

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[dharak1]

Haha that's great. I love that you can just catapult kerbals into a stable orbit.

[Padishar]

Nice... Is that Jeb and did he grin through the whole process? I guess you could probably do it with a small ship attached to the end too. Set up an action group to decouple the docking port so you can time it right. May need to spin for a few revolutions to get up enough speed with more mass on the end...

[Red Iron Crown]

Clever! I wonder how much payload can be orbited that way.

[Xavven]

You can get orbital (Pe > 70 km) with just jets (meaning no other engines) without intake air storing if you abuse the momentum conservation law a bit.

ROFL!!! You really got me there