HERMES I — A Crewed Venus Backflip Mission
HERMES I
Psychology and Communications in a Hypothetical Crewed Venus Backflip Mission
- 565days
- 136days within 11M mi of Venus
- 6crew
- 2Venus flybys
- ~0m/s ΔV post-departure
- 13.5min max comms delay
The Question
What would six astronauts face during a crewed mission to Venus?
HERMES I is a hypothetical crewed Venus backflip mission designed as a thought experiment. Before space agencies commit to a two to three year Mars transit, the question to be asked is: what actually happens to a small crew across nearly eighteen months of deep space isolation? The thought experiment came from this, and that is when research was done to find a mission that tested the journey without the need for a seperate landing phase. Venus was picked due to the backflip mechanics allowing more time for teleoperated science, and due to the fact landing on the surface is barred.
Research from analog environments (the Mars500 isolation study, Antarctic overwinter postings, long-duration ISS missions, and submarine deployments) tells us what tends to break down and when. Often, authority is questioned and the crew turns inward, starting to see mission control as an outgroup that cannot understand what they are experiencing. The third quarter of a long mission is historically the most dangerous psychologically. And then there is the return: splashdown does not end the mission for the people who flew it, with the effects of isolation lingering for years or forever.
HERMES I is designed to be questioned with all of this in mind. The mission does not treat crew psychology as a secondary concern to be managed, but as the primary system to be engineered with the same seriousness as propulsion, life support, or navigation. The thought experiment is an attempt to imagine what that engineering actually looks like across 565 days, three distinct mission phases, and the full arc from departure to reintegration.
What version 1.0 means
This is the first public cut published deliberately unfinished in results and deep dives on evidence. I feel the trajectory viz is cool to share, but beyond that the reasoning around this first pass is: this is a starting position rather than a conclusion, put out in the open for us to think on. I want the ideas here to be engaged with and built on as the months go by. Putting everything I have collected for this project out at once defeats the point of the thought experiment.
The Mission
The Spacecraft
A crew of six is worked into the thought experiment: two mission commanders, a flight surgeon, a systems engineer, a planetary scientist, and a mission specialist. They would depart Earth's orbit in August 2034 aboard the HERMES transit vehicle (named due to the mythological connection to Venus). The spacecraft is functional, with a total habitable volume of approximately 180 cubic meters across four modules: a command and operations deck, a science and medical bay, a crew quarters module with six individual berths, and a shared commons that serves as galley, recreation space, and the psychological center of gravity for the entire mission.
The total habitable volume is something to be worked on and talked about further. One of the earliest suggestions that became clear in initial research is that the more space, the better. In a thought experiment without the barrier of physics and money (two constants of space travel), that suggestion goes down easy. In reality, more space means more money, launches, and time. As such, the thought experiment is designed with 180 cubic meters as a hard limit to bolster discussion. That is the same idea with the split commander decision: how will that impact the astronauts?
The Trajectory
HERMES I uses a free-return backflip trajectory, a gravitational architecture that requires minimal propulsion after Earth departure while delivering the crew to Venus twice. The outbound transit takes the crew away from Earth across roughly three months. On November 18, 2034, HERMES I makes its first Venus flyby at 500 km altitude.
Then, rather than continuing away from Venus, the trajectory curves. The spacecraft enters a backflip geometry, looping below the plane of the solar system by approximately 15 million kilometers (a vantage point no human has ever occupied) before returning toward Venus for a second flyby on March 9, 2035.
Between the two flybys, the crew spends 111 days in continuous proximity to Venus, remaining within a light-minute of the planet at all times. This means signal delay to Venus drops to seconds and teleoperation becomes possible, such as high flying drones that drop reinforced sensors on ground to log data in all but real time. The thought experiment allows for, and assumes, that there will be materials sent ahead to orbit Venus that are able to be controlled when the crew gets there.
After the second flyby, HERMES I begins its long return. The crew arrives home on February 24, 2036. Total mission duration: 565 days.
The Work
HERMES I carries a suite of deployable robotic assets: atmospheric probes, a semi-autonomous solar-powered aircraft designed to operate within and below the Venusian cloud deck, and a teleoperated rover targeted for deployment on Maxwell Montes. That is the planet's highest peak, where temperatures drop enough to allow weeklong surface operations. These assets are assumed to be pre-deployed by earlier robotic missions and are awaiting use. Though the thought experiment is trying to be as realistic as possible, there is a certain amount of 'wish listing' we can do to make the trip better. We are talking about back flipping across the solar system, after all.
The Interactive Trajectory View
Explore the mission as a navigable object! I am proud to present this bit of programming. Scrub through 565 days of flight, watch the spacecraft loop below the ecliptic, thread two Venus flybys, and return home. The live mission panel updates with distance, phase, and signal delay as you move through time. Drag to rotate the view and see the backflip from underneath the plane of the solar system. I feel the geometry is hard to picture until you can see it, and then the mission becomes a lot more 'real'!
This is the part of version 1.0 that is finished enough to stand on its own, and the part most likely to be useful to someone else. If it renders something incorrectly, or you want a parameter exposed that isn't, send me a message!
Where To Assist
To start building solutions and putting down sourced evidence to this page, InTheAtticDev needs your help!
If you have the data, know any fun literature, or have a method that would test one of these better than the one proposed: that is the contribution I am asking for!
The third-quarter phenomenon
Looking for Longitudinal, time-series psychometric data from long-duration isolation (Mars500, Antarctic winter-overs, NEEMO, submarine deployments, long ISS increments, etc.).
To test Whether the third-quarter dip is a genuine inflection or an artifact of how missions are structured, and whether it moves when the crew is given meaningful work at the midpoint, as HERMES I does with the 111-day Venus window.
Split command authority
Looking for Writings and data about authority split between task and relationship. This could be expedition leadership, maritime command, surgical teams, remote industrial crews, and many others. Both the cases where it worked and the cases where it produced two rival groups.
To test Whether a dual-commander structure prevents hierarchy failure or simply relocates the conflict one level up where it is harder to see.
Earth-independent medical operations
Looking for Performance data on clinical decision support under communication blackout and documented cases of clinician, patient disagreement where no second opinion was available.
To test How much of a flight surgeon's authority can be delegated to a decision support system before the crews trust in it, or in the doctor, erodes?
Protocols at thirteen minutes
Looking for Research on how teams structure messages under high one-way latency, plus anything from asynchronous-first organizations that transfers. Studies on space to ground autonomy transitions especially.
To test Whether structured protocols actually prevent the space to ground silo or merely delay its formation.
A better backflip
Looking for An optimized solution for the pi transfer. The published trajectory is explicitly preliminary and not flight-optimized.
To test Whether shorter flight time or lower Earth-return velocity is achievable-- and, if so, how much of the psychological argument for the long route survives it?
The soft infrastructure
Looking for Evidence on non-hardware countermeasures: horticultural therapy and crew-tended growth systems, invented ritual and holiday making in isolated crews, and the durability of Overview Effect responses over months rather than days.
To test Would deliberately designed routines flatten the mid-mission dip, or can they cause friction and fuel isolation?
