Some of the nuclear rocket propulsion ideas propose exactly that, like Project Orion.

HPsquared 2 hours ago | parent | next [-]

Fission fragment rocket engines are also (theoretically) extremely efficient.. using the particles that come out of the reaction directly as a high-velocity exhaust stream.

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drivebyhooting an hour ago | parent [-]

FFR have super high ISP but microscopic thrust. Not exactly practical.

	▲	db48x 23 minutes ago \| parent [-]
		Practical for many missions, just not for sending humans in person to other planets. For example, consider a mission to deliver a telescope out past 550AU so that it can use the whole sun as a gravitational lens. That’s more than 11× further than Pluto, but a fission fragment drive could get the telescope out there in about the amount of time it took New Horizons to fly past Pluto.

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hedgehog 5 hours ago | parent | prev | next [-]

If you like Orion check out Project Pluto (they even built some some test bench engines)

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Izikiel43 39 minutes ago | parent | prev [-]

did they ever figure out how to brake? Spin the ship 180 degrees and bomb the front?