As Hurricane Irma looms, X-37B poised for first flight atop SpaceX Falcon 9
KENNEDY SPACE CENTER, Fla. — Continuing its breakneck launch pace, SpaceX is preparing to fly its 13th Falcon 9 rocket in the 2017 calendar year. The booster is scheduled to loft one of the U.S. Air Force’s two reusable robotic X-37B spaceplanes. However, the fifth Orbital Test Vehicle (OTV-5) mission might be facing a delay brought about by the powerful Hurricane Irma.
*Update: According to Florida Today’s Emre Kelly, SpaceX confirmed the company was targeting a 5 hour, 5 minute launch window that opens at 9:50 a.m. EDT (13:50 GMT) Sept. 7, 2017.
According to the 45th Weather Squadron on Sept. 5, 2017, the weather for this attempt is anticipated to have a 50 percent chance of unacceptable conditions. The primary concerns are thick and cumulus clouds.
Should a delay of 24 hours occur, conditions are expected to worsen as Hurricane Irma approaches. This will create low-level winds that will strengthen throughout the day. As such, concerns for a Friday liftoff are thick and cumulus clouds in addition to strong winds at launch time. The probability of a weather-related scrub is 60 percent.
In preparation for liftoff, on Aug. 31, 2017, SpaceX rolled its Falcon 9 rocket – sans the payload – up the ramp at Launch Complex 39A to perform its customary pre-flight static fire test. This involved firing up the first stage’s nine Merlin 1D engines at 4:30 p.m. EDT (20:30 GMT) for several seconds to throttle up to 1.7 million pounds-force (7,560 kilonewtons) of thrust to verify all was well with the rocket.
Ground teams then lowered the rocket and rolled it back into the nearby horizontal integration facility to attach the payload fairing with the X-37B inside.
Once the launch gets underway, SpaceX plans to recover the first stage of the Falcon 9. After stage separation, the first stage will perform a series of maneuvers to return to the launch area and land at Landing Zone-1. If successful, it will be the seventh ground-based landing and the 16th overall.
The decision to launch the OTV-5 mission on the Falcon 9 was only announced in June of 2017 during the U.S. Air Force Secretary Heather Wilson’s testimony to the U.S. Senate Armed Services Committee. United Launch Alliance’s Atlas V rocket orbited the previous four spaceplane missions. This will be the first orbited by SpaceX.
“The many firsts on this mission make the upcoming OTV launch a milestone for the program,” said Randy Walden, the director of the Air Force Rapid Capabilities Office, in an Air Force press release. “It is our goal to continue advancing the X-37B OTV so it can more fully support the growing space community.”
According to the Air Force, this mission carries small satellite ride shares and will demonstrate greater opportunities for rapid space access and on-orbit testing of emerging space technologies. Additionally, the mission will host the Air Force Research Laboratory Advanced Structurally Embedded Thermal Spreader payload to test experimental electronics and oscillating heat pipe technologies in the long duration space environment.
Everything else about the OTV-5 mission, like all of the other flights of the stubby spaceplane, is currently classified.
The 11,000-pound (4,990-kilogram) X-37B measures about 29 feet (8.8 meters) long with a wingspan of about 15 feet (4.5 meters). The vehicle sports a small cargo bay about the size of a pickup truck bed. Once the cargo bay is opened in orbit, a solar panel with gallium arsenide solar cells will be deployed to power the vehicle. Additionally, it has a single maneuvering engine that burns hydrazine and nitrogen tetroxide.
The X-37B typically orbits Earth between 200 and 250 miles (320 and 400 kilometers) in altitude, but the exact parameters are never released. However, many amateur astronomers have tracked the various orbital changes the OTV missions have performed.
Because of the spaceplanes black and white colors, some have described the X-37B as a mini-Space Shuttle. However, its thermal protection system is different from the Space Shuttle’s silica tiles. Exactly what they are made of, as well as a number of other things about the spacecraft, remains classified.
Per the U.S. Air Force, the X-37B is an experimental test program to demonstrate technologies for a reliable, reusable, unmanned space test platform. The primary objective is to develop reusable spacecraft technologies for America’s future in space and operate experiments that can be returned to, and examined, on Earth.
The X-37B was developed by Boeing’s Phantom Works division. It was originally a NASA project when the program began in 1999, but in 2004 it was transferred to the U.S. Department of Defense. In 2006, a version of the vehicle called X-37A was used in drop glide tests.
Once those were deemed successful, the program moved on to develop a modified version called the X-37B, which would be used for the U.S. Military’s OTV program.
The first flight with the first X-37B, OTV-1, launched on April 22, 2010, from Space Launch Complex 41 (SLC-40) atop an Atlas V in the 501 configuration (a five-meter fairing, zero solid rocket motors, and a single engine Centaur upper stage). It landed 224 days later on Dec. 3, 2010, at Vandenberg Air Force Base in California.
OTV-2 used a second X-37B. It launched on March 5, 2011, also from SLC-41. It spent some 468 days in orbit before also landing at Vandenberg.
The first reuse of an X-37B occurred on Dec. 11, 2012, from SLC-41 during the OTV-3 mission. It launched the same vehicle that carried out the OTV-1 mission. The spacecraft landing took place 647 days later on Oct. 17, 2014, at Vandenberg.
Finally, OTV-4 launched on May 20, 2015, from SLC-41. It used the second X-37B (first launched during OTV-2) and spent a staggering 718 days in orbit. It landed on May 7, 2017, at Kennedy Space Center’s Shuttle Landing Facility – a first for the OTV program.
In total, the two X-37B spacecraft have racked up some 2,085 days in orbit during the previous four missions. How long OTV-5 will spend in orbit is also classified.
Video courtesy of Military Material
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Derek Richardson has a degree in mass media, with an emphasis in contemporary journalism, from Washburn University in Topeka, Kansas. While at Washburn, he was the managing editor of the student run newspaper, the Washburn Review. He also has a blog about the International Space Station, called Orbital Velocity.