Adam Hibberd
Following on from my previous blog where I studied the capability of the up-coming Ariane 6 4 launcher in terms of delivering a spacecraft on a course to intercept the first interstellar object to be discovered, ‘Oumuamua, I continue this logical progression with analysis of a more powerful launcher, the Falcon Heavy.
The SpaceX Falcon Heavy is a super-heavy launch vehicle which at the time of writing, has executed four successful launches. The fourth most powerful launcher in history, this launch vehicle has two configuration options: partially reusable or expendable, the latter more capable version is investigated here.
As frequent readers to this blog may realise, a visit of Jupiter is an important prerequisite for intercepting 'Oumuamua on a reasonable timescale, and indeed a direct mission to Jupiter is feasible using this SpaceX rocket, the drawback being however that a payload mass less than 3000kg is indicated. Using the NASA online launcher query service, we find that for a C3 value of 100 km2s-2, which gets to Jupiter and more, a Falcon Heavy Expendable can achieve a mass of 750kg to this Earth-escape orbit. Is this mass upon arrival at Jupiter, sufficient to permit a solid rocket stage with payload to reach ‘Oumuamua within a realistic timeframe? The answer is a definite no.
Let us instead settle on a V-infinity Leveraging Manoeuvre, VILM, as we did with Ariane 6 4 (refer my previous blog) but, with a far more powerful capability than the Ariane 6 4 could afford, we have a choice of n=1, 2 OR 3, and the C3 for each option is presented in the Table 1.
Table 2 provides the results of this analysis, addressing each of the scenarios n=1, 2 & 3 in turn. As can be observed, the option n=2, hits the ‘sweet-spot’ for this Falcon Heavy launcher, with an overall flight duration of 28 years, and with the n=1 & 3 lagging quite significantly behind, at 54 years and 43 years respectively.
The n=2 scenario supposes that two solid propellant stages, a STAR 63F and a STAR 48B are fired at the Earth return, and then a second STAR 48B is fired at perijove. Further, as in the case of Ariane 6 4, an additional 0.5kms-1 is applied at the DSM, the reason for adopting this value is so that, as an alternative to chemical, an electric low-thrust propulsion system with high specific impulse would, over the course of the resonant orbit, be able to apply this ΔV, as required.
Go to my animation of the n=2 trajectory here: