United Launch Alliance crews at Cape Canaveral have topped off an Atlas 5 rocket for liftoff Monday with the U.S. military’s next infrared sentinel to join a satellite fleet designed detect missile launches around the world.
Ground teams at ULA’s Vertical Integration Facility installed the U.S. Space Force’s fifth Space Based Infrared System, or SBIRS, satellite on top of the Atlas 5 rocket May 7. Since then, ULA personnel have performed a series of tests to verify mechanical and electrical connections between the rocket and the SBIRS GEO 5 spacecraft encapsulated inside the Atlas 5’s payload shroud.
The preparations set the stage for rollout of the 194-foot-tall (59-meter) rocket from the vertical hangar to pad 41 at Cape Canaveral Space Force Station this weekend. The Atlas 5 will ride on its mobile launch platform along rail tracks for the 1,800-foot (550-meter) trip to the launch pad.
After connecting the rocket with ground systems — such as propellant fluid lines — at the launch pad, ULA will kick off the countdown early Monday to target a launch time of 1:35 p.m. EDT (1735 GMT).
The launch Monday will be the first Atlas 5 mission of the year, and ULA’s second flight of 2021 overall, following the successful launch of a Delta 4-Heavy rocket from California on April 26 with a classified U.S. government spy satellite.
Izstrelitev Atlas 5, ki bo vesoljsko plovilo SBIRS GEO 5 dostavila v orbito, bo letela v konfiguraciji "421" s 4-metrskimi in dvema pritrjenima trdnima raketnima ojačevalcema, ki jih dobavlja Aerojet Rocketdyne. En motor RL10 podjetja Aerojet Rocketdyne bo poganjal zgornjo stopnjo Atlas 5's Centaur.
Izstrelitev bo zaznamovala osmi let različice Atlas 5-421 in 87. izstrelitev rakete Atlas 5 od prvega nastopa leta 2002.
ULA crews at Cape Canaveral began stacking the Atlas 5 rocket on its launch table inside the VIF last month. The bronze first stage booster was raised vertical and positioned onto the launch mount April 21, a few weeks after the stage arrived at the Florida launch base from ULA’s rocket factory in Decatur, Alabama.
Twin AJ-60A solid rocket boosters from Aerojet Rocketdyne were installed on the side of the Atlas first stage April 23 and 24. The strap-on motors will give the rocket an extra boost off the launch pad, firing alongside the first stage’s kerosene-fueled RD-180 main engine.
Ground teams hoisted the rocket’s cryogenic Centaur upper stage and its Aerojet Rocketdyne RL10 engine on top of the Atlas first stage April 26. The Centaur was integrated with the rocket’s interstage and the bottom segment of the payload fairing inside a nearby processing facility before teams lifted the entire unit on top of the first stage.
The build-up of the Atlas 5 rocket was completed Friday, May 7, with the stacking of the 45-foot-tall (13.7-meter) payload fairing inside the VIF.
Workers encapsulated the SBIRS GEO 5 satellite inside the payload fairing at a clean room facility at the spaceport. The spacecraft arrived at Cape Canaveral on March 18 on a U.S. Air Force cargo plane from California, where Lockheed Martin built and tested the satellite at a factory in Sunnyvale.
Once at Cape Canaveral, the spacecraft was loaded with its supply of hypergolic hydrazine and nitrogen tetroxide propellants for in-space maneuvers.
SBIRS GEO 5 is follows four previous SBIRS satellites launched into geosynchronous orbit since 2011 to replace the military’s aging Defense Support Program missile warning spacecraft, the last of which launched in 2007. All of the SBIRS satellites in geosynchronous orbit rode to space aboard Atlas 5 rockets.
The Atlas 5 rocket launching the SBIRS GEO 5 mission will head east from Cape Canaveral. The launcher’s two solid rocket boosters will consume their pre-packed propellant in about a minute-and-a-half, then jettison to fall into the Atlantic Ocean at T+plus 2 minutes, 9 seconds.
The first stage’s Russian-made RD-180 main engine will shut down at T+plus 4 minutes, 10 seconds, followed by stage separation six seconds later. The hydrogen-fueled RL10 engine on the Centaur upper stage will ignite at T+plus 4 minutes, 26 seconds, for the first of two firings to place the SBIRS GEO 5 spacecraft into an elongated transfer orbit.
After cutoff of the Centaur’s first burn at T+plus 15 minutes, 6 seconds, the rocket will deploy two suitcase-size secondary payloads for the U.S. Air Force Academy. A second RL10 engine burn will begin at T+plus 31 minutes, 6 seconds, to maneuver into an orbit closer to the SBIRS GEO 5 spacecraft’s final operating position.
Separation of the Space Force’s new missile warning satellite is expected at T+plus 42 minutes, 46 seconds.
Računalnik za vodenje Atlasa 5 bo poskušal izpustiti vesoljsko plovilo v orbito, ki sega v višino med 575 miljami (925 kilometrov) in 22,216 miljami (35,753 kilometrov), s kotom naklona 21.14 stopinj glede na ekvator.
The SBIRS GEO 5 spacecraft’s on-board propulsion system will steer the satellite to a circular geosynchronous orbit that is continuously at an altitude of nearly 22,300 miles over the equator. In that orbit, the satellite’s velocity will be fixed with the rate of Earth’s rotation, giving the craft’s infrared early warning sensors a constant view of the same part of the planet.
Novi satelit se razlikuje od prvih štirih satelitov SBIRS GEO, saj predstavlja nadgrajeno zasnovo vesoljskih plovil, ki jo Lockheed Martin imenuje "bojni avtobus". Lockheed Martin je zgradil peti in šesti satelit SBIRS GEO s svojo novo platformo LM 2100, za katero družba pravi, da je rezultat "večletne pobude za modernizacijo, ki jo financira interno".
Po Lockheedu Martinu je bojni avtobus LM 2100 zasnovan tako, da zagotavlja večjo odpornost in utrjevanje pred kibernetskimi grožnjami, skupaj z dodatno močjo vesoljskih ladij ter izboljšan pogon in elektroniko. Modularna zasnova vključuje skupne komponente za poenostavitev proizvodnje in lažje prilagaja nove tipe senzorjev, ki se odzivajo na inovacije in nove vojaške zahteve.
Bojni avtobus LM 2100 bo uporabljala tudi naslednja generacija satelitov za opozarjanje na raketo, ki jih Lockheed Martin gradi za vesoljske sile, ki bodo nadomestile floto SBIRS. Naslednja generacija GPS-navigacijskega satelita, ki naj bi se začela izstreljevati leta 2026, bo uporabljala tudi platformo bojnih avtobusov.
Končni satelit SBIRS GEO, GEO 6, naj bi izstrelil na raketi Atlas 5 leta 2022. Pogodbe vojske z Lockheedom Martinom za zadnja dva satelita SBIRS GEO so po finančnih podatkih, ki jih je Pentagon objavil leta prejšnja leta.
Northrop Grumman gradi infrardeče senzorje na satelitih SBIRS. Instrumenti lahko zaznajo in izsledijo vroče izpušne plume iz raketnih motorjev, kar vojaške uradnike obvešča o izstrelitvah tujih raket. Informacije, ki jih je zbrala flota SBIRS, bi obrambnim enotam lahko pomagale prestreči prihajajočo raketo, preden bo zadela svoj cilj.
Ozvezdje SBIRS vključuje najmanj štiri plovila SBIRS, ki so nameščena v geosinhroni orbiti, in vsaj dva infrardeča tovora v eliptičnih orbitah na strogo tajnih vohunskih satelitih Nacionalnega izvidniškega urada, ki zagotavljajo polarno pokritost. Zadnja dva satelita SBIRS, ki bosta izstreljena letos in prihodnje leto, bosta napolnila floto.
Vsak infrardeči paket instrumentov na geosinhronih satelitih vključuje senzorje za gledanje in skeniranje, zasnovani za zagotavljanje vidljivosti na celotni polobli, hkrati pa omogočajo zemeljskim operaterjem, da osredotočijo pogled plovila na vroče točke, kot je Severna Koreja.
E-pošta Avtor.
Sledite Stephenu Clarku na Twitterju: @ StephenClark1.
