STM-D-0951Paper2014Designed, not yet built

Using VASIMR® for the Proposed Europa Mission

Edgar A. Bering III · Matthew Giambusso · Mark Carter · Andrew Ilin · Christopher Olsen · Jared P. Squire · Franklin Chang Díaz · Benjamin W. Longmier

Abstract and summary · read the original at the source · none found

In one page

Getting a spacecraft to Jupiter normally means years of looping past Venus and Earth to beg gravity for speed. Edgar Bering of the University of Houston, with Franklin Chang Díaz’s Ad Astra Rocket Company and Benjamin Longmier of Michigan, propose doing it with sunlight and a plasma engine instead. Their idea is a reusable catapult. A VASIMR-powered stage first thrusts backwards to fall in close to the Sun, where sunlight is strongest; there it turns around, spends that abundant power on a hard sustained burn, and flings its passenger onto a direct transfer orbit before returning to Earth to do it again. The engine is not hypothetical: the 200 kilowatt prototype it is based on has been run in a vacuum chamber at 72 per cent efficiency. On their trajectory models a four-tonne payload reaches Jupiter in about 35 months — roughly half the time Galileo took — with the ship, not the planets, providing the energy.

Why it matters hereChapter 8 asks what a craft can do once its performance stops being set by chemistry, and this paper is the honest top of the ladder you can climb while still throwing mass out of the back: a measured engine, a real power budget, and a Jupiter mission that halves the transit time. Chapter 9 gets the machine itself — a plasma made by a helicon antenna, heated at the ion cyclotron frequency and released through a magnetic nozzle, with no electrode anywhere in the beam.

What it claims

01The concept is a reusable probe catapult. A VASIMR stage sends a 4000 to 5000 kilogram spacecraft to Jupiter on a Hohmann-like transfer orbit arriving in just 36 months elapsed time, by making a slingshot pass close to the Sun and using the high level of solar energy available there to produce a sustained burst of high thrust; the probe is released with enough speed to reach Jupiter in three years and the catapult returns to Earth for another mission.Abstract
Designed, not yet built
02The engine has no electrodes in the plasma, and that is the whole design. A helicon discharge makes the plasma, an ion cyclotron heating stage accelerates the ions with a circularly polarised radio wave tuned to their cyclotron frequency, and a two-stage magnetic nozzle turns their gyration into directed momentum as the field weakens — thrust following from conservation of the first adiabatic invariant. Radial magnetic confinement keeps both ions and electrons off the walls, which is what allows the engine to process power densities of order 6 megawatts per square metre and still expect a long life.Section I, Introduction, and Figures 1 and 2
On the bench now
03The performance numbers are measured, not projected. The VX-200 couplers were designed for 60 per cent thruster efficiency at 5000 seconds specific impulse on 200 kilowatts of direct-current input, equivalent to 186 kilowatts of coupled radio-frequency power. Running the full 200 kilowatts of radio-frequency power, the measured performance was 72 per cent thruster efficiency at a specific impulse of 4900 plus or minus 300 seconds. Plasma production came in below the 100 electronvolts per ion that efficient operation requires, with a minimum ionisation cost of 87 plus or minus 9 electronvolts per ion, measured with the engine in a 150 cubic metre vacuum chamber held below one hundredth of a pascal.Section III, Efficiency, subsection A, Thruster Performance at 200 kW; Figures 3, 8 and 9
Published and peer-reviewed
04The mission runs in three phases and the geometry is specific. In phase one the spacecraft thrusts antiparallel to its heliocentric velocity, deliberately slowing down so that it falls in toward the Sun. In phase two it accelerates along its velocity vector while the solar flux climbs, passing inside the orbit of Venus to a perihelion of about 0.54 astronomical units. Phase three begins at about 0.73 astronomical units, where the payload already has enough energy to coast to Jupiter. The solar array is taken to be a flat planar array rather than a concentrator, because a concentrator would overheat the cells that close to the Sun.Section IV, subsection A, The VASIMR Ejector Catapult, and Figure 11
Designed, not yet built
05The vehicle is massed against a real spacecraft. The catapult is scaled from the MESSENGER design with two changes — thermal control multiplied by about eight, and propellant plus tankage increased by more than an order of magnitude — giving a full system wet mass in low Earth orbit of about 22 to 25 tonnes. A 25 tonne initial mass carrying a 5 tonne payload reaches Jupiter in 36 months, half the time Galileo needed; optimised solutions for a 4 tonne payload on a 22 tonne initial mass deliver it in 34.7 months.Section IV, subsections B, C and D, with Figures 12, 13, 15, 16 and 17 and Table I
Designed, not yet built
06What to watch is the return leg, and the authors say so themselves. Bringing the catapult home costs more argon than it delivered payload, and the reuse case assumes ten deep-space missions over twenty years, which they call unlikely in the present funding environment. Their alternative is to keep thrusting instead: carry on accelerating out past the orbit of Mars, jettison the argon tankage, magnets and thermal system in mid-course, insert into Jupiter orbit with a chemical stage, and arrive with 20 kilowatts of solar power still running and the engine’s radio-frequency generators repurposed as the transmitter of an ice-penetrating radar. That alternative has not yet been worked out quantitatively.Section IV, subsection E, An Alternative Idea, and section V, Conclusion
What to watch

Read it · abstract

Abstract

We explore the capability of a VASIMR® reusable probe “catapult” concept to send a 4000-5000 kg spacecraft to Jupiter on a Hohmann-like transfer orbit, arriving in just 36 months elapsed time. The VASIMR® performs a slingshot pass close to the Sun and uses the high level of available solar energy to produce a sustained burst of high thrust. Enough kinetic energy is provided to the probe to reach Jupiter orbit within 0.7-1.4 AU. The Catapult release the probe with enough speed to reach Jupiter in three years, and returns to Earth for another mission. This study identifies the important parameters in the probe ejector operation (power level, propellant mass, payload release point, distance of closest approach to the Sun), and scan these parameters to understand and optimize the capabilities of the proposed system. We assume that the Catapult and its payload begin at the Earth’s sphere of influence (SOI), and are coasting in the Earth’s orbit about the Sun. The VASIMR® engine’s power rating must match the peak power available when the spacecraft is closest to the Sun. The solar array is assumed to be a planar array rather than a concentrator since it will have to operate near the Sun, where a concentrator would overheat photovoltaic cells. The feasibility of not releasing the payload and using the VASIMR® to provide thrust for the duration of the transfer orbit will also be examined. In this scenario, the VASIMR® RF generators could serve double duty as radar RF sources.

Edgar A. Bering III and Matthew Giambusso, University of Houston; Mark Carter, Andrew Ilin, Chris S. Olsen, Jared P. Squire and Franklin R. Chang Díaz, Ad Astra Rocket Company; Benjamin W. Longmier, University of Michigan. AIAA paper 2014-4344, AIAA SPACE 2014 Conference and Exposition, San Diego, August 2014. Abstract as printed on the paper’s first page.

(Abstract only — see the rights note above for why the twenty-one pages of engine physics, plume measurements and trajectory analysis are not reproduced here. They are at the source.)

The propulsion neighbours on this site: the gasdynamic-mirror fusion rocket, which asks the same trip-time question with a fusion reactor in place of the solar array, is at /library/stm-1d903a7f60; inertial confinement fusion propulsion is at /library/stm-b87332054a; nuclear pulse propulsion, the other end of the mass-ejection ladder, is at /library/stm-2c84b6d280; the Defense Intelligence reports that name VASIMR while arguing for aneutronic fusion propulsion are at /library/stm-b5e092d030 and /library/stm-08b7559cf0; and the studies of what lies past reaction mass altogether are at /library/stm-c06140bc7a, /library/stm-aeca17e392 and /library/stm-00a7ce4729.

The way in

https://doi.org/10.2514/6.2014-4344WHAT THIS IS. AIAA paper 2014-4344, presented at the AIAA SPACE 2014 Conference and Exposition, San Diego, 4 to 7 August 2014. Twenty-one pages. AFFILIATIONS as printed on the title page: Edgar A. Bering III and Matthew Giambusso, Department of Physics, University of Houston; Mark Carter, Andrew Ilin, Chris S. Olsen, Jared P. Squire and Franklin R. Chang Díaz, Ad Astra Rocket Company, Webster, Texas; Benjamin W. Longmier, Department of Aerospace Engineering, University of Michigan. NAMES. The creators above follow the publisher record, with two corrections from the paper’s own byline: the suffix III on the first author, and the acute accent in Díaz. The title page prints the fifth author as Chris S. Olsen, where the publisher record has Christopher Olsen, and prints Mark Carter and Andrew Ilin, who appear in this paper’s own reference list as M. D. Carter and A. V. Ilin. LICENCE. The AIAA paper is closed: Crossref records no licence and Unpaywall reports no publisher open copy. The full text exists as a green deposit in the University of Michigan’s Deep Blue repository, handle 2027.42/140468, but the deposited file is the publisher’s own PDF, watermarked ‘Downloaded by University of Michigan — Duderstadt Center on December 13, 2017, arc.aiaa.org’, and carries no Creative Commons statement — so it is a source to read, not a text to republish. NTRS. The NASA Technical Reports Server does not hold this paper; searches on its title and on the first author return only other VASIMR items, so there is no public-domain NASA version to promote. WHAT WAS READ. The complete Deep Blue deposit, retrieved on 2026-09-08 through the Internet Archive capture of that file because the repository itself answers automated requests with a browser challenge, and read in full. Every claim below is located against a numbered section, figure or table of it. The abstract reproduced below is the authors’ own, identical in the paper and in the publisher’s deposited metadata. FIGURES. The seventeen figures and the trajectory table are not reproduced; the figures quoted in the claims are read from the running text.

How to cite it

Edgar A. Bering III, Matthew Giambusso, Mark Carter, Andrew Ilin, Christopher Olsen, Jared P. Squire, Franklin Chang Díaz, Benjamin W. Longmier (2014) Using VASIMR® for the Proposed Europa Mission. doi:10.2514/6.2014-4344

Where it sits in the curriculum

Inertial mass reduction and transmedium craft Plasmoids, charge clusters and the orbs