Curiosity was a huge project with many quite separate
parts with people with qualifications of enormous
variety. Thus, Curiosity was not just some one thing.
Also, going "beyond" Curiosity might be an objective
to be considered by a committee reporting to the
head of NASA but is not really a suitable goal
for just one person.

One way to look at Curiosity is that it is just
a platform for a collection of devices for making
scientific measurements. Each such device was
developed by a team, and no doubt the teams were
largely independent. A single device team had experts
in maybe geology, chemistry, optics, mechanical
engineering, electronics. Likely the leading
academic subject matter experts had Ph.D. degrees, but
I have to doubt that usually more than 50%
of a team did.

Once Curiosity was ready to be launched,
there was the rocket, the ground stations that
communicated with the rocket and its payload,
lots of people back at JPL working on
trajectory, guidance, data analysis,
software updates, etc., lots of people with
likely less than 10% of them with a Ph.D.

If you want to make a big splash in, say,
'autonomous vehicles', then
making progress in some part of that field
might be a suitable goal for one person. So,
look at what has been done
at Google, Stanford, CMU, etc. and funded
by DARPA, etc. Also consider aviation
from early autopilots to autonomous
drones and what more that people want.
Consider sea-based autonomous vehicles.
And, of course, the hypersonic scram
jets will have to be autonomous until
they are big enough and trusted enough
to carry a person, which stands to be
a long time.

For sending humans to Mars, my
approach, which you are welcome to borrow
if you want, is first to do a lot
with autonomous vehicles. So, before
even the first human leaves earth,
have dozens of autonomous vehicles
on Mars, awash in redundancy,
with a good camp set up
and running, and able, reliably,
to launch payloads back to earth.
Then, almost as an afterthought,
let a team of humans go,
with appropriate cosmic ray
shielding, etc. So, don't send
any humans until apparently
nearly all the risk is gone.
So, do nearly all the work with
autonomous vehicles first.
Maybe there's some work there
you'd like to do!

But, be careful: Even if autonomous
vehicles are your real interest, you
may find that mostly the qualifications
needed are in mechanical engineering,
aeronautical engineering, control
system engineering, software engineering,
electronic engineering,
etc., and each of
these is a more definite academic field.
That is, even if 'autonomous vehicles'
is a good goal for you, it may
not be a very solid academic
field for you to stand on to
achieve your goal. To know more,
just look at what there is.

On your past academic background, that
might not mean very much. A Ph.D. is
nearly all about just three things,
research, research, and research,
and nearly no one teaching in K-12
has even as much as a weak little hollow
hoot of a tiny clue about research.
Instead, in K-12, have a lot of
babysitting where the teachers, nearly
all women, want good little students,
mostly the girls, to sit still,
be nice, write neatly, be nice,
be quiet, be nice, jump through
little hoops, be nice, etc.

For me? In grades 1-8, all the
teachers in the school agreed --
I was poor student. Apparently
my standardized tests of talent
said otherwise, but that didn't
impress the teachers. So the
teachers treated me like dirt,
and I gave up on trying to please them.
In the eighth grade, my
handwriting just sucked (common
for boys). My 'clerical accuracy'
sucked -- it still does, so to get
something detailed correct I have to
do it one day, wait at least a day,
better a week, and check it. Somehow
that issue doesn't hurt my work
in software; somehow the
mistakes I make are ones a compiler
easily catches; in all the code I've
written over all the decades, I'm
not sure that even once a clerical
accuracy problem became an actual software
bug problem. Since
I have some actual talent in math,
my understanding of the algorithms,
etc. of eighth grade math was
fast without doing the homework.

So, on tests, I didn't do very well:
E.g., I didn't care enough to try
very hard. I didn't even know
why or how to try hard at academics.
So, with my poor handwriting
and poor clerical accuracy,
when I had to, say, multiply
two four digit numbers, in my
intermediate work the columns would
not line up and I would make simple
errors.

So, at the end of the year, my
eighth grade arithmetic teacher
gave me a D and
fervently advised me never to
take another course in math.

My father was actually good in education,
understood that actually I was
learning enough, and laughed at the
arithmetic teacher. Dad was correct.
For the next four years, I was likely
the second best math student in
my grade. It's a good bet that
since then I've been by a good margin
the best math student from the school
ever. The eighth grade arithmetic
teacher knew nothing about math.
Nearly none of my K-12 teachers
knew anything important about
academics. Likely none of them
knew anything about research.

Doing well in K-8 or even K-12
is not a very good predictor of
being good at research. Moreover,
doing poorly in those grades
doesn't mean much, either.

Don't let the K-12 system
evaluate your potential
for research or even academics.
Why? Because for anything significant
in either research or even just academics,
nearly no one in K-12 has even as much
as a weak little hollow hint of a tiny
clue what the heck they are talking about.

For a view of some of the excitement
of research and some of what in
'originality' is crucial, look at the
YouTube lectures of Eric Lander
on microbiology and genetics.
E.g., for a course home page,

http://ocw.mit.edu/courses/biology/7-01sc-fundamentals-of-biology-fall-2011/

Can download course text materials at

http://ocw.mit.edu/courses/biology/7-01sc-fundamentals-of-biology-fall-2011/download-course-materials/

A TOC of the videos for the course are at

http://www.youtube.com/playlist?list=PLF83B8D8C87426E44

See also Lander's

http://www.princeton.edu/WebMedia/flash/lectures/20100419_publect_lander.shtml

Not all academic research is that exciting,
but Lander's emphasis on the excitement
and crucial role of originality is
right on target quite broadly across
STEM fields.

For more, look at the background
and work of, say, Craig Venter.
One little thing he did was
take all the ideas and planning
of the Human Genome project,
trash and junk them, use a
radically different approach,
and totally knock the socks off
all the NIH team. Except for
Venter, the genome project
might be looking to be done
maybe in year 2200! As I recall,
a Venter remark was that the NIH
team was not looking to sequence
the human genome but to set themselves
up with permanent jobs!

If you want to get a Ph.D. in
a STEM field, might take a fast
read of, say,

https://news.ycombinator.com/item?id=5849936

https://news.ycombinator.com/item?id=5849938