By Mike Loucks, John Carrico and Dennis Tito

Dennis Wingo provided some comments for us in his article Inspiration Mars: Some Thoughts About Their Plan. Dennis Wingo is a friend of ours. We welcome input from any source, especially visionaries like Dennis.

Our IEEE Paper is an attempt to show the feasibility of the simplest possible Mars flyby mission. We chose a simple Mars flyby trajectory (the one from the Patel reference), and will choose a simple ECLSS, heat shield, etc., using existing designs and technologies on a single launch. We may eventually deviate from these assumptions, but only when we have proven that we must.

The paper is not an attempt to flush out every feasible technology that could be made available in the next 5 years nor does it contain all analysis that has been done by the Inspiration Mars team.

Our paper represents the work-in-progress that had been done when the paper’s deadline for peer-review came. We added additional details for the IEEE conference last week, and more will come out in the following weeks. We intend for our process to be open and public, and invite input from all sources.

We have a very experienced and savvy trajectory team, and we are aware of most of the technologies and trajectory options available. We explored those options when they were relevant, dismissed some that we felt were not, and left others for analysis at a later date.

We offer the following responses to some of Wingo’s specific points.

1. Precise targeting of Aerocapture

Our analysis of re-entry is currently incomplete. We have bounded the problem, but our current analysis does not allow us to assess injection accuracy requirements. If we do require unusually high-precision targeting, we believe that such targeting can be achieved. It might be hard, but targeting in deep space is hard. We will have a long time to adjust our trajectory on the way back to Earth, with the full resources of Earth ground systems available to help us get it right. We will team with whatever NASA experts are available to help solve these problems (JPL, JSC, etc.) in the same fashion that we have already teamed with NASA/Ames.

2. Required Volume not available in inflatable until inflated:

This is a solvable problem. The paper didn’t cover it, but our engineers have several options available that were not discussed in the paper.

3. EVME Trajectory from 2002 Okutsu/Longuski Paper

The trajectory from the 2002 paper by Okutsu and Longuski Mars Free Returns via Gravity Assist From Venus, requires a launch 10 months earlier than our nominal. We have simulated this and many other similar trajectories. This trajectory travels well inside of the orbit of Venus, down to 0.56 AU. (the orbit of Venus is approximately 0.7 AU). The departure C3 for this trajectory is better than our nominal, but the re-entry velocity is essentially identical. The excessive thermal and schedule requirements of this mission eliminated it from consideration.