Adam Hibberd
A rendezvous mission to Halley's comet? The return visit of Halley to the inner solar system won't be until around 2061, with perihelion on July 28 of that year. That's a long way away, right?
That hasn't stopped some scientists deriving a trajectory to this well-known comet, designed to RENDEZVOUS with it (go here), in other words match velocity with the object upon arrival. My approach is slightly different - see MY trajectory below.
A rendezvous usually means that you need some form of on-board propulsion such as chemical rockets to apply the necessary rendezvous velocity change (or 'DeltaV').
That got me to thinking - can I design a trajectory to Halley that would require as small an 'in-flight' DeltaV as possible after launch?
I decided that in order to minimize the arrival DeltaV, one should first match the orbital plane of the spacecraft to that of Halley's comet, which is highly retrograde, meaning that it goes the opposite way around the Sun to the planets and asteroids.
How do we EASILY achieve retrograde motion?
Well unsurprisingly Jupiter plays a huge role in the trajectory I found and there are three encounters of this planet altogether.
Fortuitously, Jupiter intersects the orbital plane of Halley's comet in January 2060, more than a year before Halley's perihelion. Yes, that serendipity can be exploited but launch has to be around one Jupiter period (11.9 years) BEFORE this alignment, way back to when Jupiter last achieved a similar alignment to Halley's orbital plane. The spacecraft is launched in 2047, goes to Jupiter, ultimately returning back to the 2060 alignment, where it conducts a third gravity assist of Jupiter in order to head towards the inner planets and rendezvous with Halley.
I show you the trajectory in the image below and now contemplating whether this is worthy of a paper.
The orange is the path taken by the spacecraft, the green dashed line is the relevant arc of Halley's orbit. The inner dashed blue circle and outer dashed circle are the planets Earth and Jupiter respectively.
