Aircraft

Special Delivery

By Jeff Rhodes Posted 26 November 2013

The countdown reached zero. The rocket motor lit. The Atlas V booster, tall as a twenty-story building, started to rise. Splitting the early morning darkness with a brilliant flash, a thundering roar, and riding on a column of smoke, the rocket climbed, began to accelerate, and then arced away from the launchpad.

Explosive bolts held the US Air Force’s third Advanced Extremely High Frequency, or AEHF-3, high capacity, jam-resistant, nuclear-survivable military communications satellite in place as the Atlas V gained speed and altitude.

The three solid rocket motors strapped to the rocket’s sides to provide additional thrust burned out and were jettisoned about two minutes into flight. The sixty-five foot tall, two-piece, European-built fairing covering both the satellite and the Centaur upper stage separated a minute and a half later.

The Russian-built, 860,000-pound-thrust RD-180 engine, having expended its propellant, shut down as planned a little more than four minutes after liftoff. First stage separation occurred six seconds later. The 25,000-pound-thrust Aerojet Rocketdyne RL-10 engine in the rocket’s Centaur upper stage then fired for the first of two planned burns.

The first Centaur burn lasted about nine and one-half minutes, placing the satellite into a parking orbit. After coasting for about eight minutes, the engine lit up again for a five and one-half minute burn, moving the satellite into transfer orbit.

At that point, the bolts fired and the satellite separated from the Centaur and began transmitting. Getting AEHF-3 to its final geosynchronous orbit approximately 22,000 miles from Earth will take about 155 days including on-orbit testing.

From liftoff to signal acquisition, the 18 September 2013 launch of AEHF-3 from Space Launch Complex 41 at Cape Canaveral AFS, Florida, took fifty-one minutes. But the process to move this thirty-one foot tall, 13,570-pound satellite from a clean room in California, transport it across the country, and up to space actually began in 2004.

Coming Down Like Rain
The AEHF system will give the US National Security Council and unified combatant commanders the ability to control tactical and strategic forces at all levels of conflict through nuclear war. The AEHF program is run by the MILSATCOM Systems Directorate, part of the Air Force’s Space and Missile Systems Center at Los Angeles AFB, California

Capable of providing ten times the data throughput of the 1990s-era Milstar system, AEHF will initially augment and then eventually replace Milstar. One engineer described AEHF’s ten megabit per second rate as “data coming down like rain.” All of the satellite’s multiple data paths are encrypted. AEHF also offers a substantial increase in coverage over Milstar.

The AEHF system will consist of six cross-linked satellites that eliminate the need for ground relay stations; a mission control segment that includes mission control, training, and logistics functions; and a terminal segment that includes fixed and ground-mobile terminals, ship and submarine terminals, and various airborne terminals.

In addition to Special Operations and a number of service-specific applications, AEHF will provide real-time situational awareness and enroute planning and targeting data for the Air Force; a battlefield common operational picture and precision engagement data for Army units; and air tasking order transmission and battle damage assessment for the Navy. Canada, Netherlands, and the United Kingdom are partners on AEHF.

AEHF-1, launched in 2010, and AEHF-2, launched in 2012, are both now operational. In addition to initial US testing, the Canadian and Dutch militaries have each conducted tests of their ground terminals. AEHF-3 will be operational in 2014.

In 2014, AEHF-4 will be assembled in the same clean rooms at Lockheed Martin Space Systems Company in Sunnyvale, California, where the Milstar satellites and numerous other satellites and spacecraft were built. AEHF-5 and AEHF-6 are in component production.

First Time, Every Time
“A satellite has to work first time, every time,” said Mark Calassa, the Lockheed Martin vice president of Protected Communication Systems who oversees the 500-person AEHF program at Space Systems Company. “There are no second chances. We can’t bring the satellite back to fix something.”

Every satellite is thoroughly tested at every stage of construction. “Counting test, it takes about 100 people seventy-two months to build a single AEHF satellite,” noted Calassa. “We test everything at the component level first and then test small numbers of components together. Testing the complete satellite takes twenty-four months.”

Unlike previous generations of satellites where the entire spacecraft was designed and built to order, AEHF, as well as satellites for the military’s other new satellite system, the Mobile User Objective System, or MUOS, use a common modular bus—the Christmas tree that the various sensors and antennae needed for a particular satellite type are hung on—called A2100.

Developed as a way to increase reliability and reduce cost for commercial satellites, the A2100 bus features a simplified structure to reduce parts count. It is made of lightweight all-composite materials to increase strength, reduce weight, and minimize thermal distortion.

Testing at the component level and assembly takes about two years. The AEHF payload is built by Northrop Grumman and is assembled in parallel to the bus components. Next comes the baseline integrated systems test, or BIST. “This is the first time the vehicle is powered on in an airtight environment,” said Calassa. “Acoustic testing, which simulates the vibration and noise of the rocket launch, comes after that.”

Thermal vacuum testing, or TVAC, which takes two months on AEHF, follows. “We simulate the environment of space and turn the satellite on. We subject it to the coldest cold and the hottest hot to make sure everything still functions,” noted Calassa. The final integrated system test, or FIST, is the comprehensive exam where the final measurements are compared with initial test results.

At this point, the pyrotechnic devices needed to open the sensor arms in space are installed, and the solar array is attached. Space Systems Company now builds its own solar cells as a way to reduce costs. When extended, the solar panels give the AEHF satellite a span of ninety-eight feet.

“We add the last thermal blankets, attach the access panel cover plates, and button up the vehicle. This whole process takes about six months,” noted Calassa. The satellite is then ready to ship.

A Very Large Box
In mid June 2013, about a month before AEHF was ready for shipment, a C-5 Galaxy transport crew flew into Moffett Federal Airfield, which shares a fence with the Lockheed Martin facility in Sunnyvale, to deliver a very large, very specialized container called MATS.

“The Miller Automated Transportation System is named after the engineer who designed it,” said Jorge Martinez, Lockheed Martin engineer whose team is responsible for all fixtures and dollies necessary to move satellites through integration, test, and transport. “Convair built MATS in San Diego in the 1980s for another program, and it was modified for SBIRS [Space-Based Infrared System] and AEHF transport in 2006. It’s a temperature- and humidity-controlled box used to safely transport satellites that cost almost $1 billion.”

The MATS container has a mechanical arm with a gimbaled motor at the base. The arm is raised, and the satellite is attached. The arm, with the satellite attached, is then rotated down cantilevered in the container. Packing peanuts or foam cutouts aren’t an option.

For as long as the satellite sits in MATS, a nitrogen purge is used to keep the electronics free from debris and protected from corrosion. The container keeps the satellite at room temperature with low relative humidity.

Early in the morning of 10 July, the MATS container, with the AEHF-3 inside, left the clean room and was transported very slowly through the common fence to neighboring Moffett Field.

“It’s an old tale that we move spacecraft at night to keep the Russian satellites from watching,” said Calassa. “There may have been something to that during the Cold War. But the fact is, a daytime loading puts stress on the environmental control system. It’s just cooler to load at night, particularly in the summer.”

Just before dawn, a crew of about twenty technicians and the aircrew gently and precisely loaded the MATS container on to the front end of the C-5’s cargo compartment. The aircrew had only the eighteen-inch width of the catwalks along the fuselage sides to get around the satellite. The gap from the top of MATS to the bottom of the aircraft’s crew compartment was only two and one-half inches. Support equipment, including a specialized tractor trailer, filled the remainder of the cargo hold.

Clear The Trees
The journey to deliver AEHF-3 actually began in October 2004, when this particular C-5B Galaxy transport (Air Force serial number 86-0013) was flown to Lockheed Martin Aeronautics Company in Marietta, Georgia. This aircraft was the first C-5 to go through the Reliability Enhancement and Re-engining Program, or RERP, modification line. New engines were installed and more than seventy other improvements were made. The transport, now a C-5M Super Galaxy, was first flown in 2006.

“A lot of these types of missions are now going to the C-5M,” noted Capt. Gene Pasker, who served as the aircraft commander on the AEHF-3 delivery flight. “The C-5M is more powerful, allowing us to fly farther, and we don’t have to stop for gas or refuel from a tanker. The new engines allow us to carry about 70,000 pounds more cargo.”

In the past, C-5Bs departing Moffett Field with high-value space cargo would often have to be under-fueled to have a sufficient weight margin in order to clear the tall trees at the end of the runway. Crews would fly to the other end of San Francisco Bay to Travis AFB to fuel and then fly across the country. For AEHF-3, the C-5M and crew took off at Moffett and headed straight to Florida.

“This is a welcome change for us. About ninety-nine percent of our missions now are to and from Afghanistan,” noted Pasker. Reinforcing his point, the floor of the C-5M flight deck on this flight was covered with removable Kevlar armor plate.

Pasker, like the rest of the crew on this flight, is assigned to the 709th Airlift Squadron, the Air Force Reserve Command associate flying unit at Dover AFB, Delaware, which is currently the only C-5M base. “The flight crew was basically the next names up on the board. We did look for a little more experience because this is a high priority mission. But with our current operational level, it was mostly a case of picking the people who were available.”

The augmented flight crew of ten—pilot, aircraft commander, relief pilot, two flight engineers, and three loadmasters—also included two flight mechanics. “We take the flight mechanics along when we go places where there’s no C-5 support,” added Pasker, who has approximately 3,000 flight hours in legacy C-5s and an additional 1,000 flight hours in the C-5M.

Despite having a national asset in the cargo hold, no special route planning was required, nor did the crew have a reserved airspace corridor. The crew flew at normal cruise speeds, but did fly a parallel path to the original flightplan and at a slightly higher altitude to avoid thunderstorms and rough air.

“About the only difference on a mission like this is we have to pay closer attention to pressure and temperature,” said TSgt. Kevin Calhoun, the lead flight engineer. “Cabin pressure has to be regulated to no more than 500 feet per minute change on descent.”

Five-plus hours after takeoff from Moffett Field, the C-5M crew touched down on the 15,000-foot-long, 300-foot-wide Space Shuttle runway at the Kennedy Space Center. The process of unloading the satellite and all of the support equipment began minutes after the engines spooled down. Portable lights were set up as the sun set.

To Astrotech And Beyond
First off the C-5 is the specialized transporter. As a safety precaution, the truck cab that was used to put the MATS container on the C-5 was flown with just enough fuel to get off the aircraft. Waiting forklift drivers moved the other boxes of gear—filled with hoists and shop aids for the satellite—onto two separate flatbed trailers. The aircraft was knelt in the back to get the truck off and was then raised.

The nose was then knelt to get the satellite off. The entire load/move team, including the aircrew, met in front of the aircraft to discuss taking the MATS off the plane. The scene looked like a larger-than-normal football huddle. The driver raised the trailer to meet the aircraft’s ramp height exactly. The trailer was then lowered in front to give the MATS container a gravity assist once it was off the aircraft.

The C-5 crew ladder was folded and raised out of the way. The team slowly, carefully pushed the MATS container out of the aircraft. Once the satellite was on the trailer, the tractor cab was switched out for a larger Peterbilt truck. An environmental control system trailer was attached to the main trailer and turned on to cool the satellite.

The convoy of satellite, ECS trailer, flatbeds, pickup trucks, and people then began the five-mile road trip to Astrotech, a separate company that processes spacecraft for launch.

Meanwhile, the C-5M crew buttoned up the aircraft and went through their preflight checks. Their day wasn’t done. They had to fly to New Mexico that night to pick up another high priority load the next morning. Flying with an augmented crew allows for a twenty-four hour crew duty day.

At Astrotech, AEHF-3 was unpacked in a clean room, inspected, and tested. Then the satellite was fueled over the course of the next week with enough hydrazine and oxidizer to propel the satellite during its planned fourteen-year operational life. The satellite was mated to the launch adapter and then encapsulated in the launch fairing.

Out To The Pad
Nearly three years before AEHF-3 lifted off, construction of the Atlas V booster that would take it to space began at the United Launch Alliance, or ULA, plant in Decatur, Alabama.

ULA is the 3,700 employee Lockheed Martin-Boeing joint venture formed in 2006 that is responsible for providing launch services for both Atlas V and Delta IV rockets. Atlas V is a legacy Lockheed Martin launch vehicle several generations removed from its 1950s-era Atlas intercontinental ballistic missile forebearer. Delta IV is a legacy Boeing booster.

The crew of the Mariner, an enclosed roll-on/roll-off ocean-going vessel brought both the booster and the Centaur upper stage of the Atlas V for AEHF-3 to Cape Canaveral AFS. The ship arrived at Port Canaveral at the end of June 2013, and the launch vehicle was trucked to the processing facility at the base. Once ready, the booster was trucked to the Vertical Integration Facility, of VIF, where it was stood upright.

“The number of solid rocket boosters depends on where you need to go and how much propulsion is needed to get into space,” noted Joe Fust, the spacecraft integration specialist who oversaw the AEHF-3 launch. AEHF-3 required three solid rocket boosters, so the launch configuration is described as 5-3-1—five-meter diameter fairing to mount the satellite, three solid rocket boosters, and one motor in the Centaur upper stage.

The encapsulated satellite comes from Astrotech, is taken to the VIF, and is attached to the rocket. “The day before launch, rocket and spacecraft travel 1,000 feet to the pad on rails,” said Fust.

In the days prior, crew exercises were held for the booster and the spacecraft teams at the Atlas Spaceflight Operations Center next to the Atlas/Centaur processing facility about six miles from the launchpad. The idea is to get the controllers used to how the launch process will be conducted. Both teams are brought together to simulate the entire launch. “For this rehearsal, the computer thinks everything is flying. We go through everything up to simulated spacecraft separation,” Fust said.

The launch director sitting in a room overlooking the control room gives permission to launch, and the launch conductor directs the individual console operators. A final poll of the launch team is taken at the built-in hold at T-minus-4 in the countdown. Just like in the movies, there is a big red button on the launch coordinator’s console that can stop the process. But computers actually start the engine and launch the rocket.

“We want to launch in the first hour of the first day of the launch window,” Fust noted. “The longer we wait, the chance of something going wrong increases.” AEHF-3 lifted off at 4:10 a.m., delayed sixty-six minutes to allow rain clouds near the pad to clear. The launch of AEHF-3 marked the seventy-fifth ULA launch and the fortieth Atlas V mission.

The C-5M crew probably missed watching the launch on TV. They were likely on another mission. Staff post-launch parties in Sunnyvale, Los Angeles AFB, and at the Cape marked the launch team’s success. But the next day, it was back to work. There’s another spacecraft to deliver and to launch.

 

Jeff Rhodes is the associate editor of Code One.
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