By Jonny Lupsha, Wondrium Staff Writer
Unprecedented audio has been released from an August 30 SpaceX launch, Teslarati reported. The Falcon 9 rocket sent multiple payloads into orbit before turning around and returning to Earth. Nuclear rockets could make interstellar travel a reality.
According to Teslarati, SpaceX recently posted online the uncut audio of a rocket launch and landing. “The rocket in question, Falcon 9 booster B1059, ended months of delays when it lifted off at long last on August 30, sending a new upper stage, payload fairing, and an Argentinian Earth observation satellite on their way to orbit,” the article said.
Also of note is how it returned to Earth. According to the article, “Booster B1059 separated from the rest of the Falcon 9 a little over two minutes after launch and quickly flipped around to perform a boostback burn—quite literally slowing down to zero from Mach 5 and then boosting several dozen miles back towards the Florida coast.”
Fuel efficiency is one of the biggest hurdles to jump when considering interstellar travel. Nuclear-powered rockets may yet hold the secret.
NERVA Going to Give You Up
Perhaps unsurprisingly, humanity has considered building spaceships with nuclear power since the 1950s.
“The United States government had two major programs that prototyped high-thrust, high-exhaust speed nuclear-propelled rockets,” said Dr. Charles Adler, Professor of Physics at St. Mary’s College in Maryland. “NASA’s NERVA project developed nuclear rockets for use in the Moon program.”
Dr. Adler said that NERVA was a conservative design, not using the full potential of nuclear energy. He said that theoretically, it would use power from a small nuclear reactor to heat hydrogen gas to very high temperatures, at which molecules would rush about at incredible speed. This speed would be redirected out from a nozzle, pushing the rocket forward.
However, even though the energy density of nuclear fuel is “a million times higher” than a chemical propellant, exhaust speeds for NERVA were estimated at just triple that of ordinary rocket fuel. Why?
“NERVA is limited by the materials used to make the rocket, which start to melt at temperatures of about 2,000 Celsius or a little higher,” Dr. Adler said. “This is what limits the exhaust speed. NERVA engines were test-fired successfully, but that’s as far as it went.” NASA stuck with tried-and-true chemical rockets for the Apollo missions instead.
I Think I’ll Stick to Taking the Bus
Dr. Adler mentioned that NERVA was a conservative idea for nuclear rocketry. A very different idea came in the form of Project Orion.
“In the 1950s, the mathematician Stanislaw Ulam came up with a far more audacious idea: blow up a nuclear bomb to move the ship forward,” he said. “[Project] Orion was always meant as a propulsion system for a crewed spacecraft. Given that, the basic problem is obvious: How do you propel the ship forward without killing everyone inside?”
Dr. Adler said there are two main issues with Ulam’s idea. The first is that acceleration would be very jerky and sudden, as opposed to the far smoother liftoff from chemical rockets. He said that a nuclear-powered liftoff would be “more staccato,” in which there would be occasional but enormous energy detonations. The second problem is protecting the crew from the radiation.
“The solution that [scientists] came up with was the idea of a pusher plate attached to the ship using a large shock absorber system—a big spring with some sort of damper that nullified the vibrations,” Dr. Adler said. “As far as anyone could tell, Orion would work; the exhaust speed is effectively 10,000 kilometres per second. Missions that take years with conventional chemical rockets take weeks with an Orion-equipped spacecraft.”
However, the problems of Orion were social, legal, and environmental. Dr. Adler said that testing the system would violate the Nuclear Test Ban Treaty of 1963, not to mention that “lifting a spacecraft off Earth on a plume of nuclear bombs is problematic from a PR viewpoint.”
Strapping a nuke to the back end of a rocket and metaphorically lighting a match under it may not be feasible, but the strength of nuclear power may still have potential in space travel.
Edited by Angela Shoemaker, Wondrium Daily
Dr. Charles L. Adler contributed to this article. Dr. Adler is a Professor of Physics at St. Mary’s College of Maryland. He received his PhD, MS, and BS in Physics from Brown University, where he focused on experimental laser physics.