Ares IV was an Earth spacecraft used during one of Humanity's early manned missions to Mars, which took place in 2032 under the command of Lieutenant John Kelly. The other members of the crew were Rose Kumagawa and Andrei Novakovich.
The Ares IV craft was made up of several connected modules, with the "Martian Command Module", located in the front, acting as the craft's bridge. This command module was cylindrical and had two pilot seats with a small curved window in front of each. The craft had seat belts on the chairs to keep the pilots secured in their seats during take-off and in the zero gravity of space.
Between the two command seats was a Spectrum video monitor and digital clock that had a series of push-buttons and switches to control the ship's systems. The mission commander sat on the starboard side, which also controlled the ship's engines and sensors. The screen in front of him showed various spatial information, such as the ship's location and video feed of the surface team on a "TM 9U Color Video Monitor."
The Ares IV had a third-generation ion drive as a propulsion system, designed for travel to Mars and back, not for deep space. The ship had an ionic power system that relayed power to all the ship's systems and was channeled through an ion distributor, the 21st century equivalent of plasma manifolds. The Ares was also able to replenish some of its own power through the use of two large photovoltaic solar panels on each side of the ship.
Communication for the Ares mission was joint-run by NASA and the ISA, so the Ares IV transmitted to and received information from NASA Mission Control in Houston, Texas. The module used a high gain antenna and, as such, there was a delay of several minutes for messages sent from Ares IV to Earth and vice versa messages. Communication between Ares IV and the surface of Mars, however, was almost instantaneous.
In the event of emergency, a small escape craft was docked directly behind the cockpit so the crew may abandon ship if necessary. The escape-craft had a rounded back to allow for entering a planet's atmosphere.
The hull of the Ares IV had a ring of flags around it, each representing a member of the International Space Agency. Also on the hull was the ISA logo. The Ares IV mission patch was an irregular hexagon with a white band around the edge which contained the spacecraft's name at the top and an image of the Ares IV module from the front with its solar panels extending beyond the edges. The bottom three sides listed the last names of the crew members, "Kumagawa Kelly Novakovich."
The Ares IV mission was set for mid-late October of 2032. Scientists Rose Kumagawa and Andrei Novakovich landed on Mars, spending several days on the surface. On the morning of October 19, Kumagawa described the sunset as beautiful, with a hint of green. Kelly, manning the craft from orbit, wished he could see the sunset as well. Kumagawa and Novakovich worked on drilling through a lava plain, breaking through the iron oxide barrier down to eight meters. They were hoping to have samples ready by the end of the day, when the signal to the craft was lost.
The signal came back a moment later as Kelly encountered turbulence in orbit. He reported an unknown object approaching his position, over 1,000 meters across with an azimuth of 121.6 on the LIDAR. Scanning the anomaly with the trans-spectral imager, his signal was lost at 0922 hours, when the anomaly overtook his ship. NASA, ISA, and the team on the surface believed Kelly had been killed and there was no trace of Ares IV. It took several weeks for a rescue ship to retrieve Kumagawa and Novakovich.
This was Humanity's first encounter with a spatial anomaly. It was later found that what Kelly encountered was a graviton ellipse, an anomaly which is attracted to EM radiation and rarely comes out of subspace.
The loss of Ares IV almost derailed future missions to Mars as it was another tragic point in the history of space exploration. But manned missions and colony attempts would eventually continue, with the Ares IV's mission and crew being cited as groundbreaking, paving the way for the future of space exploration. Mars itself was colonized seventy-one years later in 2103. (VOY: "One Small Step", "The 37's")
ISA and NASA didn't know it, but Kelly actually survived being engulfed by the ellipse, after he'd fallen off NASA's LIDAR scopes. He continued keeping log entries for several days, the last one dated October 29, 2032.
In 2376, the USS Voyager encountered the graviton ellipse and located the remains of the command module – and those of Kelly – in the Delta Quadrant. The module's database, including logs recorded by Kelly after the module had entered the ellipse, were subsequently recovered. (VOY: "One Small Step")
Interior and exterior design
From the Star Trek Encyclopedia (4th ed., vol. 1, p. 42), "The Ares 4 orbital craft and Earth return vehicle was designed by illustrator (and noted space artist) Rick Sternbach in consultation with Dr. Bruce Murray, planetary scientist and former director of NASA's Jet Propulsion Laboratory. The landing craft was a modification of an Apollo lunar module."
In a article for Star Trek: The Magazine, Sternbach suggested that Ares IV was one of the most researched designs made for Star Trek, and possibly the most realistic ever on the show. (Star Trek: The Magazine Volume 2, Issue 2, p. 49) This included detailed prop manuals composed by Sternbach and Wendy Drapanas. (p. 50)
Real world connections
There was also a real world NASA Ares program in the works. These rockets were part of Project Constellation, a renewed American effort to send Humans back to the Moon and, eventually, to Mars. The real Ares IV was intended to carry a lunar lander into orbit during its 2017 test flight.  In the real world, Project Constellation was canceled in 2010. In Star Trek Into Darkness, a desktop model of Ares V, seen as set decoration, suggested that the program wasn't canceled in the Star Trek universe.
Ares IV is referenced as "one of the early missions" to Mars, suggesting it was not the first manned mission. According to the Star Trek: Star Charts (p. 38), in 2030 the spacecraft Ares I became the first manned vessel to land on Mars.
In the novel The Rings of Time, when Captain James T. Kirk is transferred by an alien probe into the body of Colonel Shaun Geoffrey Christopher during the expedition to Saturn in 2020, he initially assumes that the Lewis & Clark is the Ares IV, having been somehow transported to his current location by the anomaly that caught it, but soon establishes that he has been sent back in time himself.