In 2014, Nextbigfuture covered a 2 pager on Mars sample return using a Spacex Dragon.
Mars Sample Return (MSR) is the highest priority science mission for the next decade as recommended by the 2013 Decadal Survey of Planetary Science. There is now a 36 page presentation at the Future In-Space Operations (FISO) Working Group Presentations on a Mars sample return using a modified Spacex Dragon.
* Falcon Heavy places Red Dragon capsule on Trans Mars Injection trajectory.
* Red Dragon is modified to carry required hardware
**Mars Ascent Vehicle (MAV)
** ± Earth Return Vehicle (ERV)
** ± Mission support hardware
** ± Arm to transfer a sample from a previous rover mission ( i.e. 2020 rover) to the ERV
* Red Dragon performs lifting trajectory EDL with Supersonic Retro Propulsion EDL paper at this 2014 IEEE Aerospace conference
* Mars Ascent Vehicle (MAV) launches Earth Return Vehicle (ERV) with sample from the surface to brief Mars phasing orbit.
* Mission can start in preferred 2022 opportunity or as late as 2026
A Mars Sample Return mission in 2022 opportunity that retrieves samples collected by Mars 2020 rover technically feasible with the use of emerging commercial technologies.
SOURCES - NASA, FISO,