The planned fourth launch of a United Launch Alliance (ULA) Atlas-V rocket with a Boeing/U.S. Air Force X-37B spaceplane on May 20 comes as the Air Force is shifting to more military spaceplane payload development instead of X-37B flight testing of its own systems.
The upcoming flight is carrying a wide variety of military technology payloads, including secret payload bay sensors, but its manifest also includes an Air Force xenon thruster important to spacecraft longevity in geosynchronous orbit, along with three small U.S. Naval Academy satellites and two small Aerospace Corp. satellites demonstrating military technologies and several more secret National Reconnaissance Office (NRO) spacecraft.
An advanced NASA materials science experiment, like one previously flown on the International Space Station (ISS) for 13 years, will also be carried on the flight, as will the 344-sq-ft LightSail developed by The Planetary Society.
ULA’s Atlas-V 501 rocket, with a 5-meter faring, no solid rocket boosters, and a single engine Centaur, will launch the X-37B into about a 350-km (218-mile) orbit, inclined 39 degrees, according to Canadian researcher Ted Molczan.
Molczan analyzed the Notice to Airman (NOTAM) issued by the Federal Aviation Administration (FAA) for the 10:45 a.m. to 2:45 p.m. EDT launch period May 20 at Cape Canaveral Air Force Station, Fla. The previous three X-37B flights have all flown in 40-43 degree orbits, Molczan told AmericaSpace.
The Centaur will then be maneuvered into a 350 x 700 km (218 x 435 mi) orbit inclined 57 degrees, where it will deploy the LightSail and other spacecraft.
“With the demonstrated success of the first three missions, we’re able to shift our focus from initial checkouts of the vehicle to testing of experimental payloads,” Randy Walden, director of the Air Force Rapid Capabilities Office overseeing the flight, said in a statement.
A full-scale spaceplane mock-up, hanging from the ceiling at Space Command Headquarters in Colorado Springs, Colo., shows a large silver “Sat-Squared” space-to-space type imagine system pointed out of the open payload bay.
It could also be a ground pointing reconnaissance system, or both, but the imaging of Russian and Chinese satellites has now become a major priority in the Air Force, Gen. John E, Hyten, AFSPC commander, said recently on “CBS 60 Minutes.”
It is virtually certain the X-37B will be, if it is not already, involved in better U.S. Sat-Squared capability, given the extremely high priority the Air Force has placed on the capability. Asked what the X-37B is for, Gen. Hyten replied, “It’s for really cool things.”
The advanced National Reconnaissance Office (NRO) KH-11 Hubble-type imaging satellites have been doing Sat-Squared images for 35 years, but the Air Force needs a much more flexible system than the huge KH-11s for that, as well as a much better capability to image potentially hostile objects in geosynchronous orbit.
As a recent example, an Air Force Captain in Space Command watched a piece of Russian space debris that had been assumed dead, suddenly wake up, then rendezvous in space with the rocket launcher it originally came from. This was seen by Space Command as a Russian Anti-Satellite (ASAT) systems demonstration, according to Gen. Hyten.
In addition to attached reconnaissance sensors, the X-37B can deploy any two of several small satellites completing development by the Air Force and U.S. intelligence community.
With a program total of 1,367 days on orbit over three missions, the X-37Bs have completed more days on orbit than all 135 space shuttle missions combined, which total 1,334 days, according to Boeing, which has built two X-37Bs.
Liftoff of the nearly 200-ft-tall Atlas-V rocket from Cape Canaveral Air Force Station’s Launch Complex 41 is scheduled for a still-classified time between 10:45 a.m. and 2:45 p.m. EDT.
As in the past, a group of Russian Energomash technicians will be sealed in a guarded Atlas Space Operations Center (ASOC) telemetry room near Pad 41 to watch real time data from their RD-180 engine as it powers the Air Force’s highly classified spaceplane aloft on 860,000 lb (390,000 kg) of thrust.
Milestones events in the secret AFSPC-5 launch countdown and launch will be approximately:
- T minus 2.7 sec. Ignition of the first stage RD-180 engine on Launch Complex 41.
- Liftoff at 1. 1 sec.
- Full 860,000 lb. thrust at 2.1 sec.
- Pitch and Roll maneuvers initiated at 18.3 sec.
- Mach 1 at 1min. 23.1 sec.
- Max-Q at 1 min. 29.1 sec.
- Faring jettison to expose X-37B at 3 min. 36.1 sec.
- Atlas 1st Stage RD-180 engine cutoff at 4 min. 13.2 sec.
- Atlas / Centaur separation at 4 min. 29 sec.
- Centaur first ignition at 4 min. 39.2 sec. for about a 12 min. 33 sec., firing to place the X-37B in about a 350 Km. (218 mi.) orbit inclined 39 deg.
- News blackout starting at about 17 min. 34 sec.
- A second Centaur burn will place the upper stage in about a 57 deg. orbit inclination for the separation of several cubesat payloads.
- By 2.5 hours after launch the Centaur will be fired a third time to dive the stage into the southern Indian Ocean.
A key element of the technology payload is a xenon fueled “Hall thruster” mounted in the payload bay.
Developed by the Space and Missile Systems Center (SMC) in Los Angeles and the Air Force Rapid Capabilities Office in Washington, D.C., the Hall thruster that will fly on the X-37B OTV-4 experiment is a modified version of the units that have propelled the first three Advanced Extremely High Frequency AEHF military communications spacecraft.
A Hall thruster is a type of electric propulsion device that produces thrust by ionizing and accelerating a noble gas, usually xenon. While producing comparatively low thrust relative to conventional rocket engines, Hall thrusters provide significantly greater specific impulse, or fuel economy. This results in increased payload carrying capacity and a greater number of on-orbit maneuvers for a spacecraft using Hall thrusters rather than traditional rocket engines.
This experiment will enable in-space characterization of Hall thruster design modifications that are intended to improve performance relative to the state-of-the-art units onboard AEHF satellites, which are part of the U.S. National Command Authority for use in nuclear war.
“Space is so vitally important to everything we do,” said Maj. Gen. Tom Masiello, Air Force Research Laboratory commander. “Secure comms, ISR, missile warning, weather prediction, precision navigation and timing all rely on it, and the domain is increasingly contested. A more efficient on-orbit thruster capability is huge. Less fuel burn lowers the cost to get up there, plus it enhances spacecraft operational flexibility, survivability and longevity,” he said.
The NRO and U.S. Navy also plays a significant role in the flight.
The Naval Postgraduate School in Monterey, Calif. developed a device called ULTRASat, the size of a picnic cooler, to carry and deploy up to 24 Cubesats. One of these units is carrying the LightSail, and at least six known other satellites has been mounted on the back of the Centuar, then will be activated when the stage has maneuvered into a 57-58 deg. orbit.
Given the size of ULTRASat there are several secret NRO spacecraft nested within the carrier in addition to several other unclassified spacecraft. They are:
—Aerocube 8/Impact: A two satellite cubesat mission by the Aerospace Corporation of El Segundo, Calif will demonstrate new electric propulsion, nano and carbon nanotube (CNT) solar cell technologies. The 7-lb system is planned to function for three months.
The prime mission of both is to demonstrate a scalable ion-electrospray propulsion system (SiEPro). Additional experiments are to measure solar cell curves and wire harnesses using carbon nanotube materials and demonstrate CNTs as a radiation shielding material.
—USS Langley: USS Langley (Unix-Space-Server Langley) is a nanosatellite built by U.S. Naval Academy. It has the two primary missions. One is to fly the Unix-Space-Server (USS) to experiment with using a server in space of Amateur Experimentation and the second mission is to continue the PSK-31 multi-user transponder experiments attempted on the previous PCSAT2 (2006) payload on the ISS and the RAFT (2007) satellite.
The spacecraft weighs 11 lbs. and has a 30 day flight. It is a proof-of-concept mission for providing global internet access via a nanosatellite constellation. The Unix Space Server (USS Langley) is a small satellite under development by a team of Midshipmen at the U.S. Naval Academy in Annapolis, Md. Linux based computers have also been used in satellites before, but never as servers. USS will provide webserver access to a ground station in Annapolis and other ground stations with a 3-meter dish and an S-band transceiver. The webserver will be accessible to users who are connected to the internet when the satellite is in range of a ground station.
—PSAT A&B: This twin spacecraft Naval Academy project involves a two way communications transponder for relaying remote telemetry, sensor and user data from remote environmental experiments or other data sources back to experimenters via a global network of internet linked volunteer ground stations. The data transponder also includes all telemetry, command and control for a two complete cubesats. The spacecraft carries two transponders, one serving the Ocean Data Telemetry Microsat Link (ODTML) mission for DOD and the other operating in the Amateur Satellite Service to encourage students, educators and experimenters around the world to contribute buoys or additional satellites for future operations.
—BRICSat-P: Also developed at the Naval Academy, the Ballistic Reinforced Communication Satellite is a low cost Cubesat that will demonstrate on-orbit operation of a Micro-Cathode Arc Thruster electric propulsion system carrying an amateur communication payload. The little satellite will do several attitude control maneuvers to demonstrate the four arc thruster heads.
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