Engineering topics

Chmielewski, Artur

Publications and source records attributed to Chmielewski, Artur.

2 records

NASA NTRS2022

Mid-Air Helicopter Delivery at Mars Using a Jetpack

Mid-Air Helicopter Delivery (MAHD) is a new Entry, Descent and Landing (EDL) architecture to enable in situ mobility for Mars science at lower cost than previous rover missions. It uses a jetpack to slow down a Mars Science Helicopter (MSH) after separation from the backshell, and reach aerodynamic conditions suitable for helicopter take-off in mid air. MAHD's lander-free approach leaves enough room in the aeroshell to accommodate larger rotors. This drastically improves flight performance compared to heritage EDL approaches, notably +60\% science payload mass. MAHD also brings cost savings, a simpler architecture, improved surface access and can reach higher elevations on Mars. This paper introduces a design for the MAHD system architecture and operations. We present a mechanical configuration which fits both MSH and the jetpack within the 2.65-m Mars heritage aeroshell, and a jetpack control architecture which fully leverages the available helicopter avionics. We discuss preliminary numerical models of the flow dynamics resulting from the interaction between the jets, the rotors and the side winds. We define a force-torque sensing architecture capable of handling the wind and trimming the rotors to prepare for safe take-off. Finally, we analyze the dynamic environment and closed-loop control simulation results to demonstrate the preliminary feasibility of MAHD.

Balaram, J.↗

NASA NTRS2003

Lightweight, Self-Deployable Wheels

Ultra-lightweight, self-deployable wheels made of polymer foams have been demonstrated. These wheels are an addition to the roster of cold hibernated elastic memory (CHEM) structural applications. Intended originally for use on nanorovers (very small planetary-exploration robotic vehicles), CHEM wheels could also be used for many commercial applications, such as in toys. The CHEM concept was reported in "Cold Hibernated Elastic Memory (CHEM) Expandable Structures" (NPO-20394), NASA Tech Briefs, Vol. 23, No. 2 (February 1999), page 56. To recapitulate: A CHEM structure is fabricated from a shape-memory polymer (SMP) foam. The structure is compressed to a very small volume while in its rubbery state above its glass-transition temperature (Tg). Once compressed, the structure can be cooled below Tg to its glassy state. As long as the temperature remains <Tg the structure remains compacted (in a cold hibernated state), even when the external compressive forces are removed. When the structure is subsequently heated above Tg, it returns to the rubbery state, in which a combination of elasticity and the SMP effect cause it to expand (deploy) to its original size and shape. Once thus deployed, the CHEM structure can be rigidified by cooling below Tg to the glassy state. The structure could be subsequently reheated above Tg and recompacted. The compaction/deployment/rigidification cycle could be repeated as many times as needed.

Chmielewski, Artur↗