Part III Chapter 8:
“...our building's shaking here. Our building's shaking! Oh it's terrific, the building's shaking! This big blast window is shaking! We're holding it with our hands! Look at that rocket go into the clouds at 3000 feet!...you can see it...you can see it...oh the roar is terrific!...”
-Walter Cronkite, reporting on Apollo 4, the first launch of the Saturn V
In April of 1977, the first Saturn V in almost two years rolled out to the pad at Launch Complex 39A. This time however, the rocket was different. The stages had been stretched a little, and the engines improved, but to an average onlooker, these changes were not apparent. What was easily visible though, was the four massive boosters strapped onto the rocket, and the much taller payload. The UA-156 boosters attached to the side of the Saturn VB boosted its payload significantly. Due to the fact that the boosters were loaded with solid propellant before being shipped to the Cape, the crawlers that would carry the rocket to the pad had to be significantly upgraded. Each booster fully loaded massed more than an empty Saturn V. The upgrades to the crawler had been one of the major factors delaying this launch, but now everything was ready.
NASA was promoting this flight as “Ares T-1” the first official flight of the Ares program, despite the fact that multiple test flights had flown before this in service of Ares. For the maiden flight of the new Saturn VB, NASA had asked hardware directors to come up with a payload that was “useful but expendable”, meaning something that would further Ares along, but nothing important enough that it couldn't risk being destroyed if things went awry. Because of this, Ares T-1 would carry a “semi-functional” boilerplate version of the PPM. The module would have the same mass and flight characteristics as a PPM, but without the nuclear engines that could cause some issues if the Saturn VB blew up. The boilerplate PPM would be outfitted with most of the cryogenic storage equipment that the final version would have, and would perform further tests on long duration storage of liquid hydrogen.
On April 28, 1977, Ares T-1 lifted off, blasting into the sky. Unlike Apollo missions, where the low thrust to weight ratio of the Saturn V meant that the rocket lumbered into the sky, the solid boosters of the Saturn VB got the rocket off the pad much quicker, surprising onlookers used to the slow motion launch of the older rocket. The Saturn VB rose on the power of it's boosters and F-1A engines. One hundred and fifty seven seconds after liftoff, the solid boosters burned out and were jettisoned. Less than a minute later, the S-1D stage burned out, and was jettisoned. The S-IIB upper stage ignited, it's 5 J-2S engines pushing the payload into orbit. After Ares T-1 reached a stable orbit, the prototype PPM deployed the radiator panels and solar panels that the real thing would use. The refrigeration systems came online, and the several months long cryogenic storage tests would begin.
Like with Apollo, NASA had devised a list of mission types for the Ares program. A class missions would be tests of the Saturn VB, like Ares T-1. B class missions would be tests of the Apollo Command Module at Mars return speeds. C class missions would involve testing the PPM in a full up, interplanetary configuration. D class missions would be unmanned MEM tests, while E and F class missions would be manned MEM tests, with the F class flights reentering and landing on Earth. G Class missions would involve a crew performing a simulated Mars mission in a Mission Module in Earth Orbit. H Class missions would involve a full up test of the entire Mars stack, in a manned flight to the Moon, or high Earth orbit, I class missions would be the Mars Orbital flight, and J class missions would be the landings themselves.
Like with Apollo, this mission schedule found itself heavily modified as the program went along. The first major change was the cancellation of the H class missions, as it was determined that the C class missions, and the I class Mars orbital flights would allow testing of PPM assembly on orbit. The F class MEM Earth landings were also cancelled, deemed too risky. The G class missions were also scrapped, in favor of performing simulated Mars missions aboard Starlab.
In July of 1977, another important test occurred. However, this flight would not be given an Ares mission designation, simply being referred to as “TDF-4”. A Saturn II was rolled out to pad 37. It carried a Centaur upper stage, and atop that, the first prototype Block IV Command Module. It was not even mounted on a Service Module. This was to be the first “B Class” mission. The Saturn II lifted off, with the S-IVC upper stage placing the Centaur and CM into an elliptical orbit. After this, the Centaur fired, pushing the Apollo into an even more elliptical orbit. The CM separated, and coasted up to apoapsis. After reaching the top of its orbit, it began falling back towards the Earth, gaining velocity. On its way back down, the CM flew by the Moon, picking up even more speed. Finally, just before reaching Earth, solid rocket motors mounted under the CM fired. The CM struck the atmosphere at interplanetary trajectories. The heatshield had been beefed up for this, and it sure was necessary. Due to the way that reentry heating increased more than exponentially with a higher speed, the shock heating was brutal, much stronger than that experienced on Apollo. The same lifting reentry techniques were employed, along with the first ever American use of “skip reentry”. Finally, after several hellish minutes, the CM emerged, scarred and charred, but intact, descending under a canopy of parachutes. The TDF-4 capsule would be retrieved and and analysed further.
In September 1977, the first Saturn VA was rolled to the pad for Ares T-2. Because it was missing the boosters that defined the VB, it resembled the Saturn V used for Apollo They payload this time was a boilerplate mock-up of the Mission Module and Apollo CSM, and the first prototype MEM. The second flight of the Saturn VB went off perfectly, launching Ares T-2 into a near-orbit on October 3. The mass simulator proved that the launch configuration was aerodynamically stable. The shroud surrounding MEM-3 (MEM-1 and MEM-2 being ground test articles) was jettisoned, and the prototype module oriented itself. While the boilerplate MM and CSM would disintegrate, MEM-3 would be proving the reentry technology needed for landing on Mars. MEM-3, like the TDF-4 capsule, reentered at high speed over the Pacific Ocean. The craft transmitted telemetry data the whole way down. As it descended, the atmosphere gradually slowed it. The Pathfinder missions had greatly informed this flight, and maneuvering techniques were incorporated. As heating died down, the craft initiated the second part of the test. A drogue chute deployed, and pulled out a massive Ballute. The Ballute was quickly inflated, and began providing drag, slowing MEM-3 further. Because the Terrestrial atmosphere was much thicker than the Martian one, the vehicle was slowed much more quickly, and was soon subsonic. After the vehicle became subsonic, the Ballute was jettisoned. A small capsule, the flight data recorder, was jettisoned from the MEM as well. It deployed a parachute for recovery, while MEM-3 continued falling, and destructively smashed into the Pacific.
After the results of the test, the Ares T-3 mission was scheduled for February 1978. Ares T-3 would combine the final B class CSM test, with the first D Class MEM test. The first unmanned orbital test of the full-up MEM was a big deal. This was the Ares program's version of the Apollo 5 flight. North American had been preparing this test vehicle for several years. The design process for the MEM had been the source of many headaches at NASA and at North American. The MEM had to be one the most capable and reliable spacecraft ever built, and had to fit into a very specific mass budget. Originally, mission planners had counted on an MEM that would mass in at under 50 tons. By 1978, this had grown to over 65 tons. The mass growth of the MEM had cut into many different mass budgets, across the program. The MEM had to be incredible capable, and to squeeze more performance out of the vehicle, novel technologies would be needed. Initially it was planned for the MEM to use an already untried fuel combination of liquid oxygen and methane. But it soon became clear that even that wouldn't cut it. To get even more performance, it was decided to switch from using regular oxygen as the oxidiser, to using a mixture known as “FLOX-30” that was 70% oxygen, 30% fluorine. This was a very dangerous and toxic fuel combination, but it was deemed necessary. Engineers argued that it was not significantly more dangerous than the hypergolic fuels that had been used on many spacecraft, even manned ones, and besides, every Ares mission would involve nuclear propulsion, and that had been deemed an acceptable risk. Technicians that worked on the MEM on the ground had to wear hazmat suits, to protect themselves from the toxic fuel. Despite these hurdles, the MEM was ready by for Ares T-3.
MEM-4 would be put through its paces on this flight. Ares T-3 lifted off on February 13, 1978, once again using a boosterless Saturn VA. The MEM and CSM were delivered to an elliptical orbit. The CSM separated and went off to do its thing like on TDF-4, but the MEM was activated for its own series of trials. The solid rocket retro package mounted underneath the heatshield of MEM-4 was fired, to lower its periapsis around Earth, grazing the atmosphere. As the lander descended into the upper atmosphere, it performed further tests of the descent guidance system, and heatshield. The atmospheric density at this height in the Earth's upper atmosphere, was roughly analogous to what was to be expected at Mars. The MEM used the atmosphere to slow itself, lowering its orbit. Finally, after emerging, the MEM used the onboard reaction control thrusters to raise the periapsis back out of the atmosphere, into a circular orbit. The heatshield and shroud were then ditched, and the descent engine was tested. This was the first ever firing of a Methane powered engine in space. The engine performed as expected, and then, ascent stage separated. The ascent stage was also ignited, and an ascent was simulated, even dropping the drop tanks as each was expended. An anomaly occurred when one drop tanks failed to separate. However, it was not a mission ending event, and with some corrective steering, the simulated ascent continued. After exhausting its propellant, the MEM was commanded to re-enter the the atmosphere, this time for a destructive reentry. Further tests were given the go ahead, with Ares T-4 planned for November.