I'm sure many readers of Universe Today are, like me, fans of the science fiction genre. From the light sabers of "Star Wars" to the neuralyzer of "Men in Black," science fiction has crazy inventions aplenty and once science fiction writers dream it, scientists and engineers try and create it. Perhaps the holy grail of science fiction creations is the warp drive from "Star Trek" and it is fair to say that many have tried to work out if it is even possible to travel faster than the speed of light. To date, alas, to no avail but if the warp drive eludes us, what about faster-than-light communication.

Let's start with the warp drive. The concept is a drive that can propel a spacecraft at speeds in excess of the speed of light. According to the "Star Trek" writers, the speed was described in factors of warp speed where they are converted to multiples of the speed of light by multiplication with the cubic function of the warp factor itself. Got it. Don't worry, it's not crucial to this article.

When spacecraft return to Earth, they don't need to shed all their velocity by firing retro-rockets. Instead, they use the atmosphere as a brake to slow down for a soft landing. Every planet in the solar system except Mercury has enough of an atmosphere to allow aerobraking maneuvers, and could allow high-speed exploration missions. A new paper looks at the different worlds and how a spacecraft must fly to take advantage of this "free lunch" to slow down at the destination.

Aerocapture is an orbital transfer maneuver in which a spacecraft makes a single pass through a planetary atmosphere to decelerate and achieve orbit insertion. On the other hand, aerobraking uses a propulsive burn plus repeated dips into the atmosphere—i.e., atmospheric drag—to gradually slow the spacecraft and reduce the size of the orbit to achieve orbit insertion.

The new paper posted to the arXiv preprint server, by Athul Pradeepkumar Girija from the School of Aeronautics and Astronautics at Purdue University, notes that one of the significant risks associated with aerocapture is the uncertainty in the atmospheric density.