Sample Access Port Assembly
Cryogenic Sample Insertion and Retrieval Port
Thermally engineered access ports with motorized gate valves and vapor barriers enabling robotic sample insertion and retrieval while minimizing thermal disturbance to dewar contents
Purpose
Provide controlled physical access to dewar sample racks for robotic insertion and retrieval of individual cryovials, while limiting thermal ingress to prevent temperature excursions above the -150°C glass transition threshold in adjacent samples
Context
Access ports are the engineered compromise between sample accessibility and thermal isolation. Each dewar has one or more ports with motorized gate valves, cold vapor curtains, and optimized neck tube geometry. During a retrieval operation, the port opens for <60 seconds, during which cold nitrogen vapor forms a protective curtain. The neck tube is designed with a high length-to-diameter ratio to minimize parasitic heat leak during both sealed and open states. Ports must interface with L1-ROB robotic arms for fully autonomous sample handling.
Principles
- ▸Neck tube length-to-diameter ratio >5:1 minimizes conductive and radiative heat leak
- ▸Cold nitrogen vapor curtain at port opening prevents warm gas ingress during access events
- ▸Motorized gate valves provide rapid open/close (<5 seconds) to minimize thermal exposure time
- ▸Baffles and radiation shields within the neck tube reduce radiative heat transfer
- ▸Access event thermal budget must be managed — each opening adds quantified heat to the dewar
Typical implementations
- ▸Custom gate valve assemblies with cryogenic-rated actuators (pneumatic or stepper motor)
- ▸Vapor-phase biobank access systems (Chart Industries, Cryotherm designs)
- ▸Radiation-baffled neck tubes with multiple intermediate temperature shields
- ▸Robotic port adapters with alignment guides and force-limited insertion mechanisms
Lunar considerations
- ▸No atmospheric gas to warm port opening — lunar vacuum provides partial thermal protection
- ▸Nitrogen vapor curtain must be managed in vacuum (may require contained vestibule approach)
- ▸Lunar dust exclusion from port mechanism is critical — labyrinth seals or covers required
- ▸Reduced gravity simplifies vertical sample extraction (less gravitational force on vials)
- ▸Port actuators must function reliably at cryogenic temperatures in vacuum
Specifications
Functional
| primary function | Enable robotic sample access while limiting thermal disturbance to cryogenic storage volume |
| inputs | Retrieval/insertion commands from L2-CRY-INV, Robotic arm end-effector engagement from L1-ROB, Electrical power for gate valve actuators from L1-PDM |
| outputs | Physical access path to sample rack positions within dewar, Thermal disturbance profile per access event (quantified heat input), Port status telemetry (open/closed/locked) to L1-CDH |
| port open time seconds | <60 per retrieval/insertion event |
| gate valve cycle time seconds | <5 open or close |
| thermal penalty per access j | <500 (heat input per port-open event) |
| adjacent sample temperature rise c | <2°C during access event |
| neck tube length to diameter ratio | >5:1 |
| design life cycles | >10000 open/close cycles |
| design life years | 100 |
Physical
| dimensions | TBD — neck tube ~100mm ID x 500mm+ length |
| materials | Stainless steel 316L (neck tube, gate valve body), Aluminum 6061 (radiation baffles within neck tube), Indium seals (gate valve sealing surfaces), Stepper motor with harmonic drive (gate actuator), G-10 fiberglass (thermal break sections) |
| cold end temperature k | 77 |
| warm end temperature k | 100-200 (depending on vault ambient) |
| vacuum | Lunar ambient at warm end, nitrogen vapor at cold end |
Operational
| power consumption w | 15 |
| thermal range c | -196, -70 |
| lifetime years | 100 |
| mtbf hours | 500000 |
Interfaces
Provides
- Standardized port aperture and alignment features for robotic arm engagement and vial manipulation
- Real-time port state (sealed/open/locked) and thermal budget tracking for inventory operations
Requires
- Neck tube penetration flange on dewar outer vessel with alignment features
- Cryogenic gate valve seal and neck tube vacuum boundary sealing
- Electrical power for gate valve actuators and position sensors
- Open/close commands synchronized with robotic retrieval operations
Cite this entry
Lunar Ark Codex. "Sample Access Port Assembly" (L3-CRY-TANK-PORT). Retrieved 10 September 2026, from https://lunarark.com/entry/L3-CRY-TANK-PORT
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.