How effective would the ARES aircraft be?

Question

NASA has been working on a glider aircraft they wanted to send to Mars - this is the Aerial Regional-scale Environmental Survey. (ARES)

How long would it be able to travel? What would be the possible maximum distance for ARES to travel through?

Answer 1

According to this documentation (PDF) from 2012 on mission implementation of The Aerial Regional-scale Environmental Surveyor (ARES) Concepts and Approaches for Mars Exploration by Levine et al., NASA Langley Research Center:

Transition, extraction, and deployment of the ARES aerial vehicle use proven methods demonstrated during the airplane technology development. After release, the aerial vehicle will fly a 500 km flight path to perform the aeromagnetic survey, determine local radiation levels, search for the presence and concentration of chemically active gases, measure atmospheric dust and electric fields, and measure the local density and wind. All data will be transmitted to either the carrier spacecraft as it flies by Mars or to an existing orbital asset.

So the mission goal was for this aerobot to fly 500 kilometers. As for its capabilities to sustain flight in Martian atmosphere, since its proposal mentions the use of a rocket system to achieve flight, its total range would be limited by the amount of the rocket propellant it could still fly with, and was in no way meant as a permanent addition to the Martian skies. I wasn't able to find any theoretical limits to this proposed aerobot's maximum range, but since the last (2012) proposal dropped any idea of using other propulsion technologies, I would expect the mission objectives as described before to match its theoretical total range well enough. So, 500 kilometers ± an acceptable margin of error?

Since I wasn't able to answer your question better (I was stuck at those 500 kilometers with my search, and other references I could find were even older), here's a nice image of artist's impression on how the ARES aerial platform could look like while performing its survey of the red planet:

               

Answer 2

The concept was not a glider, but powered. It used storable biprop propellant rocket thrusters to fly at best for 81 minutes at 140 m/s. That comes out to a 680 km flight. With margins applied for mass growth during development, the range would be at or above the science requirement of 500 km. Once the propellant runs out, then it is a glider, but not for long. It's mission would end impacting the surface at high speed.