1) What do you think is the coolest fact or thing about Mars?
Just simply that it's another planet in our solar system with so much
more for us to discover and learn about, such as its history and
composition.
2) Is the Spirit rover coming back to Earth? If so, how is it getting
back? If not, will we ever see pictures of it from space?
Spirit and Opportunity will not return to Earth. All of the data that
the rovers collect are sent back to Earth via radio waves, so there is
no need to bring the rovers back to Earth once they have completed their
missions. As far as seeing the rovers again, we actually have already
seen pictures of the lander,
parachute and shell that Spirit used to enter the martian atmosphere
and land. A camera on the Mars Global Surveyor, a satellite orbiting
Mars, has imaged the Spirit landing site. You can't make out much detail
in the images, but you can see the general shapes of the objects. I
think that in the future, if we get satellites orbiting Mars with higher
resolution cameras, we will be able to see Spirit and Opportunity again.
However, the rovers will probably be obscured by a thick layer of
Martian dust that will build up over time.
3) How long does it take for a signal from Earth to reach Mars? Is it
possible to speed it up?
On the day that Spirit landed, it took about 9 minutes and 30 seconds
for a signal to go from Earth to Mars. We
communicate with the rovers
using radio waves which travel at the speed of light. We haven't found
anything that travels faster than the speed of light, so there is no way
to get our signals to and from Mars faster. Since there is one fixed
speed at which our signals can travel, the time that it takes the signal
to travel from Earth to Mars is based on the distance between Earth and
Mars. The two planets are moving apart in their orbits, so the time for
a signal to travel between them is increasing. By Spirit's sol 90 it
will take about 16 minutes for a signal to travel between Earth and
Mars.
4) Why were the first pictures from Spirit and Opportunity in black and
white?
The first images of Mars were black and white because the first images
were taken with engineering cameras, not science cameras. Engineering
cameras are used to control and navigate the rovers. Basically,
engineering cameras are looking out for objects, so these cameras do not
need to be color cameras. Black and white images are just fine when you
are trying to figure out how big and far away an object is. Engineering
cameras have a larger field of view, so one image from an engineering
camera shows a lot more of the area than an image from a Pancam would
show. But, although the Pancams have a smaller field of view, they can
capture much more of the detail in the scene than the engineering
cameras can. So, after the engineering images are taken to get an idea
of what is around the rover, the Pancam images are taken to get a view
of the scene in more detail and in different colors.
Actually, all the pictures sent back from Spirit and Opportunity are
black and white. Each camera's CCD (the part of the camera that the
image is collected on) can only detect the brightness of an object in a
scene. The relative brightness of the light detected by different
pixels (different light measuring bins on the CCD) is saved as a series
of numbers. Bright objects have high values in this series of numbers
and dark objects have low numbers. Most of the cameras on the rovers do
not have filters, so all we have is information about how bright objects
are. The Pancam cameras have different filters that can be put in front
of the lens of the camera so that only a certain color (called
wavelength) of light is let into the camera. The CCD then detects how
bright or dark an object is in one small range of wavelengths. Images
taken through red, green and blue filters can be combined into a color
image—an image that shows us colors close to what we would see if
we were looking at Mars with our own eyes.
5) Are they ever going to send people to mars?
Yes, humans will go to Mars. Throughout history, humans have explored
the Earth. Now that we are developing the capability to leave the Earth
(humans have been to the Moon several times and live on the
International Space Station for many months at a time) the next frontier
for humans to travel to and explore is our neighboring planet, Mars.
6) Will there be another rover launch in the future?
Scientists and engineers are already planning robotic missions to Mars
to be launched in the next several years.
