There’s a starman waiting in the sky
SpaceX successfully launched its Falcon Heavy with the now-famous payload of Starman (a mannequin in a SpaceX-designed spacesuit) in Elon Musk’s personal Tesla Roadster.
Test flights usually are sent up with payloads of negligible value like concrete or steel blocks, since there is the high likelihood of the mission failing, destroying that payload.
“That seemed extremely boring.”
Elon Musk @elonmusk
Well, we wouldn’t want Musk, who runs SpaceX, Tesla, has five sons (not including Kyle and Dan) and recently dated Amber Heard to get bored, would we?
He’s told us not to blow it
Once the euphoria of the successful launch was subsiding, the outstanding question became, how far will Starman go? Apparently this was an open question even within SpaceX.
“The fuel could freeze, and the oxygen could vaporize, all of which could inhibit the third burn, which is necessary for the trans-Mars injection.”
Elon Musk, February 5, 2018
“Third burn successful. Exceeded Mars orbit and kept going to the Asteroid Belt.”
Elon Musk, February 6, 2018
What a difference a day makes. I was a little surprised that SpaceX couldn’t predict how much propellant was available with more precision, so I looked into the subject.
Cause he knows it’s all worthwhile
It turns out that estimating how much liquid is in a tank floating in space is a challenge. This paper Electric Capacitance Volumetric Tomography ECVT for Fuel Gauging Under Zero Gravity (which rumor has it is the working title for the next Michael Bay movie) outlines a novel method of getting an accurate fuel reading in space. In it, the author Benjamin Butler writes:
“Currently there is not a proven method for accurately measuring the amount of propellant in real time. Because of this, spacecraft must carry extra fuel to compensate for this uncertainty, reducing the payload capacity.”
This research team is exploring the use of electric capacitance volumetric tomography (ECVT) to determine fuel volume in space vehicles. This has the promise of providing reliable and non-invasive fuel gauging. Principle 28 – Substituting of Mechanical Systems with Electromagnetic Systems
It strikes me that Musk, with his tendency to eschew mechanical systems in favor of electromagnetic ones, might adopt this technology for SpaceX’s space faring vehicles.
