Raumfahrt - Startvorbereitung für Atlas 5 mit USAF AEHF 5 Satelliten


Atlas 5 rocket, U.S. Air Force satellite arrive at Cape Canaveral for June launch


The first stage of ULA’s Atlas 5 rocket is unloaded from the Mariner transport ship after arriving at Cape Canaveral on April 21. Credit: United Launch Alliance

Atlas 5 rocket hardware and a U.S. Air Force communications satellite have arrived at Cape Canaveral for United Launch Alliance’s next mission, scheduled for liftoff June 27.

The equipment arrived at the Florida spaceport last weekend on separate shipments aboard an Air Force C-5 cargo plane and and ULA’s Mariner transport vessel.

The Air Force’s fifth Advanced Extremely High Frequency communications satellite rode a C-5 airlifter from Lockheed Martin’s factory in Sunnyvale, California, and arrived at Cape Canaveral on April 20. The rocket-carrying Mariner transport ship arrived at Port Canaveral on April 21 after a trip from ULA’s manufacturing plant in Decatur, Alabama, delivering the first and second stages of AEHF 5’s Atlas 5 launcher.

Teams will spend the next couple of months readying AEHF 5 and the Atlas 5 rocket for liftoff June 27 from Cape Canaveral’s Complex 41 launch pad. The mission will mark the 80th flight of an Atlas 5 rocket since 2002, and the first Atlas 5 launch of the year.

The Atlas 5, designated AV-083, will launch in its most powerful variant with five strap-on solid rocket boosters built by Aerojet Rocketdyne and a 5-meter-diameter (17.7-foot) payload fairing made by Ruag Space, a configuration known as the Atlas 5-551 that has flown nine times before. The five solid-fueled motors will provide an extra boost to the Atlas 5’s first stage, powered by a Russian-made RD-180 main engine that burns kerosene and liquid oxygen propellants.

The combined power of the boosters and main engine will give the Atlas 5 around 2.6 million pounds of thrust at liftoff.


ULA’s Mariner transport ship carries rocket hardware from the company’s factory in Decatur, Alabama, to launch sites in Florida and California. Credit: United Launch Alliance

Workers unloaded the Atlas 5’s first stage and Centaur upper stage, powered by an Aerojet Rocketdyne RL10 engine, from the Mariner transport ship Monday. ULA teams transferred the first stage to the Atlas Space Operations Center for checkouts before it is stacked vertically on the mobile launch platform at the Complex 41 launch pad. The Centaur upper stage will be be integrated with an interstage adapter and the lower part of the Atlas 5’s payload shroud in the coming weeks, according to ULA.

Ground crews will hoist the Atlas 5 first stage, five solid rocket boosters and the Centaur upper stage on the mobile launch table inside the Vertical Integration Facility at Complex 41. Working in a nearby clean room, technicians will fuel the AEHF 5 satellite and encapsulate the spacecraft inside the Atlas 5’s nose cone before raising the payload atop the launcher inside the VIF.

The launch of AEHF 5 follows Atlas 5 missions that deployed four previous AEHF satellites in 2010, 2012, 2013 and 2018.

The AEHF satellites provide secure communications services to the U.S. military, working together in a network the Air Force says is resilient to jamming, cyber attacks, and even nuclear war. The AEHF spacecraft are positioned in geostationary orbit more than 22,000 miles (nearly 36,000 kilometers) over the equator, using a cross-linked architecture allowing the satellites to relay signals between one another without transmitting to ground stations.

The spacecraft are built by Lockheed Martin, with communications payloads produced by Northrop Grumman.


Artist’s concept of an AEHF satellite in orbit. Credit: U.S. Air Force/Lockheed Martin

“The payload supports communication missions with increased coverage, capacity, and protections against electronic jamming which gives our warfighters the best advantage against our adversaries,” said Brig. Gen. Steve Whitney, program executive officer for the Space Production Corps.

The AEHF network is also used by Canada, the United Kingdom and the Netherlands, and replaces the Air Force’s aging Milstar constellation.

Quelle: SN


Update: 30.04.2019


Lockheed Martin's AEHF-4 On-Orbit Test Proves Successful And Marks First Of Its Kind

SUNNYVALE, Calif., April 29, 2019 /PRNewswire/ -- Lockheed Martin (NYSE: LMT) is excited to announce the successful completion of AEHF-4 spacecraft on-orbit test and available for Satellite Control Availability (SCA).

The AEHF-4 on-orbit test (A4 OOT) successfully activated the payload, built by its major subcontractor, Northrop Grumman, and demonstrated that AEHF-4 met all of its requirements. A4 OOT was the first ever test to have all six AEHF operational terminals communicating over XDR. The terminal types include AEHF SMART-T, FAB-T, MMPU, NMT, Global ASNT and ACF-IC2.


"This is a major milestone to celebrate with our customers at Space and Missiles Systems Center (SMC) the U.S. Air Force and our teammates Northrop Grumman, L3 Communications and Aerojet. As we turn our focus on launching AEHF-5 in June, one month early, I want to congratulate everyone involved in completing this one of a kind, high-performance network in space. This is a tremendous accomplishment for the AEHF program and I am proud of the team for consistently exceeding the customer's mission needs," said Mike Cacheiro, vice president of Protected Communications for Military Space.

The addition of AEHF-4 to the constellation provides a new capability of global extended data rate (XDR) communications. XDR communications provides data rates to its users five times higher than medium data rate (MDR) and 350 times higher than low data rate (LDR) communications. Milstar, the predessor to AEHF, uses both LDR and MDR communication modes to directly support the warfighter.

This was the last step before control authority of the satellite is handed over to the U.S. Air Force SMC where it will join the combined AEHF-Milstar constellation. 

The AEHF constellation provides global, survivable, highly secure and protected communications for strategic command and tactical warfighters operating on ground, sea and air platforms. The jam-resistant system also serves international partners including Canada, the Netherlands and the United Kingdom.

Quelle: Lockheed Martin