Atlas V successfully launches NROL-61 reconnaissance satellite

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United Launch Alliance successfully launched a satellite for the US National Reconnaissance Office Thursday aboard an Atlas V rocket. Liftoff for the mission designated NRO Launch 61, or NROL-61, occurred from Cape Canaveral’s Space Launch Complex -41 (SLC-41) at the start of the launch window that opened at 08:37 local time (12:37 UTC).

NROL-61 Launch:

Thursday’s mission was United Launch Alliance’s (ULA) twenty-third in support of the National Reconnaissance Office – as well as the thirteenth Atlas V launch for the agency.

Hazard areas announced ahead of the launch show that the rocket headed East-South-East towards a geostationary transfer orbit. However, the identity of the payload remains uncertain.

2016-07-27-231728The National Reconnaissance Office (NRO) is responsible for the fleet of satellites used by US intelligence agencies for surveillance, as well as in supporting roles such as research and development or communications.

With the exception of a few demonstration missions, details of the NRO’s spacecraft and operations are kept classified, with spacecraft only being identified publicly by means of their launch number and a public designation assigned after launch consisting of the letters USA, followed by a number.

Since 2007 the USA designations have been assigned sequentially, so once in orbit, the payload of Sunday’s launch is expected to become USA-269.

Despite their classified status, it is usually possible to identify types of satellites and gain a reasonable understanding of their missions through a combination of amateur observations – both visual and satellites’ radio profiles, knowledge of similar unclassified missions, historical information and leaks – such as NRO budget documents released to the Washington Post by Edward Snowden in 2013.

By comparing trends in carrier rocket selection – both performance and payload fairing capacity – and launch profiles, most spacecraft can be identified with a fair degree of certainty before they even launch. NROL-61, however, launched atop an Atlas V 421 rocket, a configuration that has not previously been used by the NRO.

2016-07-27-231246The spacecraft itself was encapsulated within an Extra-Extended Payload Fairing (XEPF) – at 14 metres (46 feet) in length the longest of three available four-metre (13-foot) diameter fairings – which has also never before been used for an NRO mission.

Quasar communications satellites and Intruder ocean surveillance satellites have previously used the less powerful Atlas V 401 configuration, with the 12.9-metre (40 ft) Long Payload Fairing (LPF) and 13.1-metre (43 ft) Extended Payload Fairing (EPF) respectively.

One Intruder launch used a 411 configuration – also less powerful than the 421 – with an EPF; it is believed that this was done to eliminate the need for a coast phase from the ascent after the previous Intruder launch suffered a propellant leak during this stage of the mission. Subsequent launches have reverted to the 401.

The Atlas V 411 with an Extended Payload Fairing has also been used for two launches of an elliptical-orbit signals intelligence satellite, identified by observers as “Improved Trumpet” or “Advanced Trumpet” as the programme’s real name is not known and the previous-generation satellites were named “Trumpet”.

2016-07-27-230943A more recent launch identified as a followup used an Atlas V 541 with a short five-metre diameter fairing – indicating a change of generation with the satellites, and in any case, the expected ground track of Thursday’s launch would not be consistent with the orbital inclination required for either a Trumpet or an Intruder.

Other NRO missions launched by the Atlas V have been Topaz radar imaging satellites, which use the 501 configuration and can only launch from Vandenberg Air Force Base in California due to their retrograde orbits, and the USA-250 or NROL-67 satellite which was orbited by an Atlas V 541 in April 2014.

The most likely explanation is that NROL-61 will be the first in a new generation of Quasar satellite; which would appear to be larger in both size and mass than its predecessors.

Quasar, also known as the Satellite Data System, or SDS, is a constellation of communications satellites operated by the NRO to support its other intelligence-gathering activities; relaying data from other satellites to the ground in real-time, without having to wait for the intelligence-gathering satellites to pass over ground stations on friendly territory.

OA-NASA-Space-Flight-304x234-FinalIf NROL-61 represents a new version of Quasar, it will be the fourth generation of the constellation.

The first-generation form of Quasar consisted of six or seven satellites, all of which operated in highly elliptical Molniya orbits. The first Quasar, OPS 7837, launched in June 1976 atop a Titan III(34)B rocket, the same configuration that would be used for all first-generation launches.

The same type of rocket was also used to launch Jumpseat signals intelligence satellites to similar orbits and with several launches it is not clear which type of spacecraft was deployed, leading to a small amount of uncertainty as to how many Quasars have been launched.

The Titan IIIB was retired in February 1987; it is likely that either this launch, or the previous flight two years earlier, carried the final first-generation Quasar.

The geostationary element of Quasar was introduced with the second generation of the constellation, with one satellite being placed into geostationary orbit and three or four into Molniya orbit.

2016-07-27-231444The first satellite, USA-40, was deployed from Space Shuttle Columbia during the STS-28 mission in August 1989, using an Orbus-21S perigee motor to achieve Molniya orbit.

USA-67, the second satellite of its generation, was deployed by Space Shuttle Atlantis during 1990s’ STS-38 mission.

The first Quasar to be placed into geostationary orbit, it is now known to have been launched alongside a second satellite, Prowler, which was kept hidden from observers via a well-orchestrated series of manoeuvres combined with the satellite’s own low-observability.

The presence of two upper stages – one from USA-67 and one from Prowler – led to the assumption that USA-67 had used a two-stage Inertial Upper Stage, and observers initially assumed it to be an Orion SIGINT satellite.

2016-07-27-231618Molniya launches continued with USA-89, which was deployed from Discovery during STS-53 in December 1992 – becoming the final NRO payload to fly aboard the Shuttle – and USA-125, which was launched by a Titan IV in July 1996.

The next satellite, NROL-5 or USA-137, may either have been the first third-generation satellite, or the last second-generation. Boosted by an Atlas IIA rocket, it was launched into Molniya orbit in January 1998 and was the only NRO launch to use an Atlas IIA.

The significantly more powerful Atlas IIAS was used for the next three launches – two of which went to geostationary orbit and the third to Molniya – in December 2000, November 2001 and August 2004 respectively.

2016-07-27-232209Following the Atlas II’s retirement – the 2004 Quasar launch was its final flight – Quasar launches switched to the Evolved Expendable Launch Vehicles (EELVs) – the Atlas V and Delta IV. The first Quasar to launch aboard an EELV, USA-198 or NROL-24, was carried by an Atlas V 401 in December 2007, achieving a Molniya orbit.

All launches since have been geosynchronous; including NROL-27 or USA-227 aboard a Delta IV Medium+(4,2) in 2011, and NROL-39 or USA-236 and NROL-33 or USA-252 atop Atlas Vs in 2012 and 2014.

The lack of recent Quasar launches to Molniya orbit has prompted speculation that this element of the constellation may no longer be maintained. With three satellites required, then the eighteen-year-old USA-137 – or an older spacecraft – would still need to be operational to ensure continuous coverage.

Second-generation satellites are believed to be based around an HS-380 series bus, along with Leasat and Intelsat VI, which had lifespans of twelve and thirteen years respectively, while even today the typical lifespan of a modern communications satellite is only about fifteen years, so it seems unlikely that the NRO would be counting on this spacecraft – and hence the Molniya aspect of Quasar, to continue in service without replacement.

2016-07-27-230846If NROL-61 is a fourth-generation Quasar, the use of a larger rocket to deploy it would suggest a larger and more powerful spacecraft than its predecessors.

Thursday’s launch was the sixth flight of an Atlas V 421 and the fifth to geostationary transfer orbit. The previous geostationary satellites launched by this configuration were two Wideband Global Satcom spacecraft, which used Extended Payload Fairings, and the commercial ICO G1 and Morelos 3 communications satellites which used the Extra-Extended fairing.

The ICO satellite, since renamed EchoStar G1, was based on Space Systems Loral’s LS-1300 bus, while Morelos – also known as MEXSAT-2 – was based on Boeing’s BSS-702HP-GEM bus. Both carried large reflector antennae to facilitate communications via mobile communication devices. It is, therefore, possible that a fourth-generation Quasar may carry a similar antenna.

An alternative explanation would be that the fourth-generation satellites are smaller than their predecessors, but will now launch in pairs. NRO budget documents published by the Washington Post in 2013 show combined line items for Quasars 17 and 18, 20 and 21 and 22 and 23, while Quasar 19 was procured separately and may have been the satellite launched in 2014, with 17 and 18 having previously launched separately.

It is possible that two Quasars could be among the three contracts awarded by the US Government to Boeing in early 2013 for BSS-702SP satellites, a modified version of the Boeing 702 platform optimised for dual launch, to be launched together by a single Atlas.

SpaceX has already conducted two dual-launch missions of BSS-702SP satellites for commercial operators Eutelsat and Asia Broadcast Satellite using its Falcon 9 rocket.

2016-07-27-230747The mission patch for NROL-61 features the Atlas rocket climbing away from Earth, with Spike, the NRO’s lizard mascot for the mission, riding the rocket into orbit. Four stars appear on the patch; three solid stars above the Earth, with the outline of a larger fourth star lower down, near the payload fairing of the rocket.

As the NRO have been known unofficially to hide clues about the identity of their payloads in the mission patches, these four stars could be seen to represent the four generations of Quasar; the hollow star representing the new generation beginning with Thursday’s launch.

Spike and the four stars also feature prominently in United Launch Alliance’s promotional poster for the mission, which shows Spike sitting atop the Earth with the rocket in the foreground; the solid stars are to the right of the rocket with the hollow star – again larger than the others – above and to the left next to Spike’s head.

2016-07-27-231108The launch patch, a second icon produced for the mission, shows the Earth surrounded by a mesh of overlapping arch shapes forming a twelve-pointed star.

The outline of the patch itself has thirteen edges, likely representing the fact that Thursday’s launch is the thirteenth Atlas V mission for the NRO.

The NRO have released two cartoon images featuring Spike ahead of the launch, which appear to form part of an outreach exercise to increase interest in spaceflight amongst children.

The Atlas V that carried out the NROL-61 mission had the tail number AV-065.

Its 421 configuration means that the vehicle consists of a single Common Core Booster (CCB) first stage augmented at liftoff by two Aerojet AJ-60A solid rocket motors, a single-engine Centaur upper stage and a four-metre payload fairing to encapsulate the NROL-61 spacecraft, protecting the payload during the ascent through Earth’s atmosphere.

2016-07-28-133742Following a nominal countdown, the Common Core Booster’s RD-180 main engine ignited at the 2.7-second mark in the countdown, reaching liftoff thrust at zero.

Ignition of the solid rocket motors and liftoff of the vehicle occurred 1.1 seconds later, with the Atlas departing from Cape Canaveral’s Space Launch Complex 41 and ascending towards orbit.

A few seconds into flight the rocket began a series of manoeuvres to attain its planned launch trajectory, with an azimuth of 99 degrees taking it East-South-East over the Atlantic Ocean.

AV-065 reached Mach 1, the speed of sound, 47 seconds into its flight, passing through the area of maximum dynamic pressure, or Max-Q, five seconds later. A little over ninety seconds after liftoff the solid motors burnt out; however, these remained attached until 129 seconds mission elapsed time.

First stage flight concluded with booster engine cutoff, or BECO, four minutes and ten seconds after launch; the Common Core Booster shut down, its engine having depleted its propellant.

2016-07-28-134221The spent stage was jettisoned six seconds later, with ignition of the Centaur’s RL10C-1 engine occurring ten seconds later. The final event before the mission entered a news blackout was the separation of the payload fairing at four minutes and thirty-four seconds after liftoff.

Third-generation Quasar satellites were launched into low-perigee geostationary transfer orbits; assuming NROL-61 targetted a similar orbit this would have called for two burns of the Centaur’s engine prior to spacecraft separation.

The first of these would have lasted around eleven minutes, followed by a ten-minute coast and a four-minute second burn. An alternative profile, to achieve a higher-perigee orbit, would call for a longer first burn and shorter second burn, separated by a coast phase of more than ninety minutes.

ULA did release the confirmation the mission was successful.

2016-07-27-232844A hazard warning announced for the Pacific Ocean between 20:59 and 22:00 UTC suggests the Centaur will be deorbited at the end of its mission, eight or nine hours after an on-time liftoff.

This suggests that the stage will complete one revolution in geostationary transfer orbit, with a deorbit burn following spacecraft separation.

Ted Molczan, one of the leading members of the amateur satellite observing community, has speculated that from the orientation of the disposal hazard area the Centaur is likely to perform a manoeuvre that will reduce the orbital inclination of the deployment orbit around 13.9 degrees.

Thursday’s launch was the fourth mission of the year for Atlas and the sixth for United Launch Alliance. NROL-61 is the third NRO mission to be launched in 2016, following NROL-45 which launched on a Delta IV Medium+(5,2) in February and NROL-37 which flew aboard a Delta IV Heavy last month.

United Launch Alliance will next be in action in mid-August when a Delta IV is slated to conduct the AFSPC-6 mission; likely to consist of the second pair of Geosynchronous Space Situational Awareness Program (GSSAP) space surveillance satellites. Atlas will next launch in early September with NASA’s OSIRIS-Rex asteroid sample return mission.

The NRO’s next launch will be in December, with an Atlas V 401 flying from Vandenberg on the NROL-79 mission – currently expected to be a pair of Intruder ocean reconnaissance satellites. A further Atlas V 421 launch, NROL-52, is currently scheduled for October 2017 and may be the next flight of the same type of payload as on Thursday’s launch.

(Images via ULA and L2 Historical).

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