YES!! Really. It's a refly - not a redesign.

I suppose Moore's Law has become so thoroughly internalized that one's immediate, reflexive response to "it's a refly" is "except for the electronics, of course, right? right?"

When you are trying to fly a new mission for a cost of $1.5B (vs. $2.5B for MSL) you have to find some significant cost savings.

Commercial products continue to see incremental improvements, but not on the exponential trend which was true until about 10 years ago.

Regarding's Doug's "Really?" to Doug:

Computer hardware has ceased its breakneck rate of accelerating speeds which was a given (Moore's Law) for decades. Commercial products continue to see incremental improvements, but not on the exponential trend which was true until about 10 years ago.

Is this a different organizational structure than the MSL MastCams?

Was MSSS part of more than one proposal?

SHERLOC is an arm-mounted, Deep UV (DUV) resonance Raman and
fluorescence spectrometer utilizing a 248.6 - nm DUV laser and 50
micron spot size. The laser is integrated to an autofocusing/scanning
optical system, and co - boresighted to a context imager with a spatial
resolution of 30 μ m. SHERLOC operates over a 7 × 7 mm area through
use of an internal scanning mirror. The 500 micron depth of view in
conjunction with the MAHLI heritage autofocus mechanism...

Last week, NASA’s managers announced the selection of seven instruments for its 2020 Mars rover from a pool of 58 proposals submitted by teams of scientists. Reading through the capabilities of the instruments makes them seem like technology from science fiction, complete with lasers and x-rays. However, the types of instruments that weren’t selected say almost as much about the goals and expectations for the mission as those that were. This mission will be optimized for finding the best samples to return to Earth rather than carrying out the most sophisticated science that could have been sent to Mars.

Yes SHERLOC will be included and it is a good instrument that will be able to get around the measurement methods used on MSL/Curiosity where we cannot be certain if the chlorobutane and chlorobenzene is actually or if they were baked together by the rover from perchlorates and other organics, (yes I am frustrated that we cannot even learn what organics that have been encountered. Like sending someone on fieldwork who do not know what an indicator species is and why it is important in any study.)
The righthand-lefthand organic and direct DNA search experiments that was in the pipeline for MSL but removed in the wild revamp to get the rover finished do not appear to be included or considered this time.

My understanding is that the 2020 instruments will be better at detecting the presence of organics than MSL, but without a mass spectrometer the rover will not be able to do detailed characterization of the organic composition. If samples are eventually returned, then that identification can be done with exquisite detail in Earth laboratories. If the samples aren't returned, then we will be left wondering what the organics are.

By using lasers, the 2020 instruments avoid the perchlorate-organic-destruction trap that comes from heating samples. There were instruments proposed that combined lasers with mass spectrometers, but they would have required the space effectively reserved for the atmospheric oxygen extraction experiment and they might have busted the instrument budget.

Instruments is built by universities so there's no direct cost there...

Instruments is built by universities so there's no direct cost there,

Is the whole 24-page article based purely on images? I couldn't find any mention of evidence from the other instruments, though admittedly that was a skim.

...a reason to have a second thought on what instruments should be included on the 2020 rover mission...

The instruments for 2020 have already been selected. It would take something much more definitive than this to change that now.

Meteorites have been raining down on us from Mars for several gigayears;

There are standard procedures to ensure a given upper limit of spores per surface area of different parts of a probe/rover/parachute etc. to avoid forward contamination. The type of possibly remaining contamination can be determined to avoid possible confusion with Martian material.
Baking on Mars doesn't make sense in this context, since chemical compounds would be altered/destroyed, including geological/mineralogical data.
Sterilization of the probe is done pre-flight on Earth.
I don't see any reason why NASA should change these established procedures.

HOUSTON — While it sizes up high-value landing site candidates for its next Mars rover, NASA is developing strategies for protecting dozens of potential rock and soil samples cached on the red planet for harvest and return to Earth at some time in the future.
The Mars 2020 science objectives are to reach a landing site with ancient astrobiological potential and geological diversity, look for rocks with high potential for biosignatures, and acquire and preserve samples of rocks and some soil for future return to Earth.
Soon, the space agency expects to name an eight-member multi-disciplinary sample-return science board to gather additional advice on the most aggressive attempt yet to scrutinize samples of Mars with the latest in Earth-bound laboratory technologies. The objective is to determine if the neighboring planet was host to extensive habitable environments, such that it possibly harbored some form of life.
"The community is critical to the process," stressed planetary scientist John Grant, co-chair of NASA's Mars Landing Site Steering Committee, on Aug. 4, opening day of a three-day workshop on the site selection process in Monrovia, California, near the project's NASA Jet Propulsion Laboratory headquarters. A second workshop is expected to reduce 30 potential landing-site candidates to eight, some of which may need additional scrutiny from NASA's Mars Reconnaissance Orbiter and other spacecraft circling or on the surface of the red planet. A third workshop planned for next year will attempt to cut the list of candidates to three or four sites.
Mars 2020, a $1.5 billion mission using hardware similar to the more expensive Mars Curiosity rover now exploring Mount Sharp, is scheduled for launch in July or August of 2020, with a landing in February 2021. Curiosity marks its third anniversary on the red planet on Aug. 6.
Early in its Gusev Crater roving, Curiosity established the presence of potentially habitable environments, setting the scientific table for its more ambitious sibling.
"One thing I must emphasize," Ken Farley, the Mars 2020 project scientist, told the opening session of NASA's 2nd Landing Site Workshop. "These are all equal goals. We must do all of these."
Using the same landing technique that produced Curiosity's "seven minutes of terror," the Mars 2020 rover will aim for a 10 X 8.75-mi. landing ellipse, where it can use its mobility to explore two "regions of interest."
As the landing-site selection process moves forward, NASA will evaluate whether to incorporate a terrain relative navigation (TRN) system into the entry, descent and landing system that would allow the descending rover to move slightly to avoid a previously unrecognized ground hazard. The TRN option is funded at least through the project's Preliminary Design Review in early 2016, Farley said.
The rover will be equipped with as many as 50 sample tubes, with at least 20 assigned to samples gathered during the rover's primary mission and the remainder available for potential extended operations.
The rover's seven primary science instruments were selected last July.
Most of the samples will be cored from rocks and all cached in sealable metal tubes. Mars 2020 will not be able to analyze the samples by itself, but could examine the walls of the rocks where the samples were extracted. The samples gathered from the first region of interest will be placed on the open terrain at a pre-specified caching depot. The Mars 2020 rover will then move on to the second region of interest for additional sample gathering and later return to the same caching depot to drop off the new samples.
The open exposure of the rover has raised concerns that surface temperatures on Mars could become high enough, especially if a landing site in the Martian southern hemisphere is selected, to degrade the cached samples before they can be gathered and returned to Earth.
"We are investigating how to deal with this," Farley said.
The current strategy is to coat the sealed tubes with aluminum oxide to reduce the excessive temperature threat to long-term preservation.
Still, the fate of the samples is unclear. NASA is focused on the human exploration of Mars in the mid-2030s; that would provide one possible means of transporting them back to Earth. Previous attempts to mount a robotic sample-return mission have been thwarted by technical and cost obstacles.