After Delays, Falcon 9 Rocket Back on Launch Pad With Starlink Satellites

 In Space
SpaceX’s Falcon 9 rocket stands vertical on pad 39A on Thursday morning. Credit: Spaceflight Now

After a six-week delay for undis­closed rea­sons, SpaceX raised a Falcon 9 ver­ti­cal on its launch pad Thursday at the Kennedy Space Center in Florida for anoth­er try early Friday to send into orbit the company’s next batch of Starlink Internet relay sta­tions and a pair of com­mer­cial BlackSky Earth-imag­ing microsatel­lites.

The 229-foot-tall (70-meter) launch­er is set for take­off at 1:12:05 a.m. EDT (0512:05 GMT) Friday from pad 39A at the Kennedy Space Center with 57 more Starlink satel­lites.

It will be SpaceX’s first launch to carry a full set of Starlink satel­lites equipped with new sun­shades, or visors, in an attempt to make the space­craft less vis­i­ble to ground-based tele­scopes, address­ing con­cerns voiced by astronomers that thou­sands of Starlink satel­lites could inter­fere with sci­en­tif­ic obser­va­tions.

“All Starlink satel­lites on this flight are equipped with a deploy­able visor to block sun­light from hit­ting the bright­est spots of the space­craft — a mea­sure SpaceX has taken as part of our work with lead­ing astro­nom­i­cal groups to mit­i­gate satel­lite reflec­tiv­i­ty,” SpaceX says on its web­site.

Two com­mer­cial Earth obser­va­tion satel­lites from BlackSky will accom­pa­ny the Starlink pay­loads into orbit, taking advan­tage of SpaceX’s rideshare ser­vice, which sells excess capac­i­ty on Falcon 9 mis­sions to other com­pa­nies.

The mis­sion set for launch Friday was orig­i­nal­ly sup­posed to take off in late June, but SpaceX has delayed the flight mul­ti­ple times. The com­pa­ny has not dis­closed any details about the nature of the prob­lems — other than weath­er — that have delayed the Starlink/BlackSky mis­sion.

The Starlink/BlackSky launch was sup­posed to take off June 26, but SpaceX delayed the mis­sion to con­duct addi­tion­al pre-launch check­outs, the com­pa­ny said on Twitter. A launch attempt July 8 was scrubbed min­utes before liftoff by poor weath­er.

SpaceX called off anoth­er launch attempt July 11, and the com­pa­ny again said offi­cials made the deci­sion “to allow more time for check­outs,” with­out pro­vid­ing fur­ther details.

The con­cerns that delayed the Starlink/BlackSky launch have not affect­ed other SpaceX mis­sions.

SpaceX suc­cess­ful­ly launched two Falcon 9 rock­ets June 30 and July 20 from Cape Canaveral with a U.S. mil­i­tary GPS nav­i­ga­tion satel­lite and the Anasis 2 mil­i­tary com­mu­ni­ca­tions satel­lite for South Korea.

The Starlink/BlackSky launch was ten­ta­tive­ly planned to launch last week from the Kennedy Space Center, but there were range safety con­cerns about the Falcon 9 rocket taking off from a pad near where NASA’s Perseverance rover — with a nuclear power gen­er­a­tor on-board — was being read­ied for take­off.

SpaceX says the Falcon 9 rocket poised for launch Friday will be pow­ered by a kerosene-fueled first stage boost­er that pre­vi­ous­ly flew on four mis­sions, begin­ning with the launch of the company’s Crew Dragon space­ship on its first unpilot­ed test flight to the International Space Station on March 2, 2019.

Since then, the reusable first stage boost­er — des­ig­nat­ed B1051 — launched and landed suc­cess­ful­ly on mis­sions June 12, 2019, and Jan. 29 and April 22 of this year. This will be the fifth flight of this par­tic­u­lar first stage boost­er.

The launch early Friday will be the 90th flight of a Falcon 9 rocket since 2010, and the 13th launch by SpaceX so far this year.

A Falcon 9 first stage booster lands on SpaceX’s drone ship Jan. 29 in the Atlantic Ocean following a previous Starlink launch. The same booster will launch again on Friday’s mission. Credit: SpaceX

SpaceX’s launch team will ready the rocket for load­ing of super-chilled, den­si­fied pro­pel­lants Thursday night, before the start of the countdown’s auto­mat­ed sequencer at 12:37 a.m. EDT (0437 GMT).

At that time, kerosene and liquid oxygen will begin pump­ing aboard the Falcon 9 rocket’s first stage, and kerosene will start flow­ing into the rocket’s second stage. At 12:56 a.m. EDT (0456 GMT), SpaceX will start fill­ing the second stage with its liquid oxygen supply.

In the final 10 min­utes of the count­down, the Falcon 9 will begin chill­ing its engine plumb­ing for igni­tion, acti­vate and check out its hydraulic sys­tems, and pres­sur­ize its cryo­genic pro­pel­lant tanks for flight.

Nine Merlin 1D engines will flash to life at the base of the Falcon 9 rocket, and hold-down clamps will open to allow the launch­er to fly away from pad 39A at 1:12 a.m. EDT (0512 GMT).

Heading north­east over the Atlantic Ocean, the Falcon 9 will sur­pass the speed of sound before shut­ting down its first stage engines at T+plus 2 min­utes, 32 sec­onds. Four sec­onds later, the boost­er will sep­a­rate to begin a con­trolled descent toward SpaceX’s drone ship “Of Course I Still Love You” parked in the Atlantic Ocean nearly 400 miles (about 630 kilo­me­ters) down­range from Cape Canaveral.

The boost­er will target a propul­sive land­ing on the float­ing plat­form nearly eight-and-a-half min­utes into the mis­sion.

Meanwhile, the Falcon 9’s second stage will ignite its single pow­er­ful Merlin 1D engine at T+plus 2 min­utes, 44 sec­onds, to drive the 57 Starlink satel­lites and two BlackSky pay­loads into a pre­lim­i­nary orbit.

The second stage engine will shut down at T+plus 8 min­utes, 51 sec­onds, to begin a coast halfway around the world before reignit­ing for a few sec­onds at T+plus 47 min­utes, 18 sec­onds.

That will inject the Starlink and BlackSky satel­lites into a near-cir­cu­lar orbit rang­ing in alti­tude between 241 miles (388 kilo­me­ters) and 249 miles (401 kilo­me­ters) above Earth, with an incli­na­tion of 53 degrees to the equa­tor.

The two BlackSky satel­lites will deploy from the top of the stack of Starlink satel­lites 61 and 66 min­utes after liftoff.

BlackSky, based in Seattle, is deploy­ing a fleet of Earth obser­va­tion satel­lites designed to mon­i­tor changes across Earth’s sur­face, feed­ing near real-time geospa­tial intel­li­gence data to gov­ern­ments and cor­po­rate clients. The two 121-pound (55-kilo­gram) satel­lites on Friday’s mis­sion will become the fifth and sixth oper­a­tional space­craft in BlackSky’s fleet, which the com­pa­ny could even­tu­al­ly number more than 50 satel­lites, depend­ing on cus­tomer demand.

The deploy­ment of the BlackSky pay­loads will set the stage for sep­a­ra­tion of the 57 Starlink space­craft at T+plus 1 hour, 33 min­utes, or at 2:45 a.m. EDT (0645 GMT).

SpaceX’s Starlink net­work is designed to pro­vide low-laten­cy, high-speed Internet ser­vice around the world. SpaceX has launched 538 flat-panel Starlink space­craft since begin­ning full-scale deploy­ment of the orbital net­work in May 2019, making the com­pa­ny the owner of the world’s largest fleet of satel­lites.

With Friday’s launch, SpaceX will have deliv­ered 595 Starlink satel­lites to orbit since May 2019.

SpaceX plans to debut a new sunshade structure on its future Starlink satellites. Credit: SpaceX

Each of the flat-panel satel­lites weighs about a quar­ter-ton, and are built by SpaceX in Redmond, Washington. Once in orbit, they will deploy solar panels to begin pro­duc­ing elec­tric­i­ty, then acti­vate their kryp­ton ion thrusters to raise their alti­tude to around 341 miles, or 550 kilo­me­ters.

SpaceX says it needs 24 launch­es to pro­vide Starlink Internet cov­er­age over nearly all of the pop­u­lat­ed world, and 12 launch­es could enable cov­er­age of higher lat­i­tude regions, such as Canada and the north­ern United States.

The launch Friday will be the 10th mis­sion to carry Starlink satel­lites into orbit, but the Starlink space­craft deployed on the network’s first ded­i­cat­ed launch were designed to demon­strate satel­lite and pay­load per­for­mance. SpaceX has not said if any of those satel­lites might be incor­po­rat­ed into the oper­a­tional fleet.

The Falcon 9 rocket can loft up to 60 Starlink satel­lites — each weigh­ing about a quar­ter-ton — on a single Falcon 9 launch. But launch­es with sec­ondary pay­loads, such as BlackSky’s new Earth-imag­ing satel­lites, can carry fewer Starlinks to allow the rideshare pas­sen­gers room to fit on the rocket.

The ini­tial phase of the Starlink net­work will number 1,584 satel­lites, accord­ing to SpaceX’s reg­u­la­to­ry fil­ings with the Federal Communications Commission. But SpaceX plans launch thou­sands more satel­lites, depend­ing on market demand, and the com­pa­ny has reg­u­la­to­ry approval from the FCC to oper­ate up to 12,000 Starlink relay nodes in low Earth orbit.

Elon Musk, SpaceX’s founder and CEO, says the Starlink net­work could earn rev­enue to fund the company’s ambi­tion for inter­plan­e­tary space travel, and even­tu­al­ly estab­lish a human set­tle­ment on Mars.

SpaceX fans sleuthing through coding on the Starlink web­site last month found images of a pro­to­type ver­sion of the anten­na con­sumers will use to con­nect to the Internet net­work.

Musk respond­ed to the tweet, writ­ing the the Starlink ground ter­mi­nal “has motors to self-orient for opti­mal view angle. No expert installer required.”

SpaceX has not released pric­ing infor­ma­tion for the Starlink ser­vice.

SpaceX says it will soon begin “beta test­ing” using the Starlink net­work. The com­pa­ny is collecting email infor­ma­tion and mail­ing address­es from prospec­tive cus­tomers, and SpaceX says it will pro­vide updates on Starlink news and ser­vice avail­abil­i­ty to those who sign up.

The beta test­ing is expect­ed to begin for users living at higher lat­i­tudes — such as the north­ern United States and south­ern Canada — where the par­tial­ly-com­plete Starlink satel­lite fleet can pro­vide more con­sis­tent ser­vice. SpaceX will send a Starlink kit includ­ing a small anten­na, router and other equip­ment to people select­ed for beta test­ing.

Astronomers have raised con­cerns about the bright­ness of SpaceX’s Starlink satel­lites, and other com­pa­nies that plan to launch large num­bers of broad­band satel­lites into low Earth orbit.

The Starlink satel­lites are brighter than expect­ed, and are vis­i­ble in trains soon after each launch, before spread­ing out and dim­ming as they travel higher above Earth.

SpaceX intro­duced a darker coat­ing on a Starlink satel­lite launched in January in a bid to reduce the amount of sun­light the space­craft reflects down to Earth. That offered some improve­ment, but not enough for ultra-sen­si­tive obser­va­to­ries like the U.S gov­ern­ment-funded Vera Rubin Observatory in Chile, which will col­lect all-sky images to study dis­tant galax­ies, stars, and search for poten­tial­ly dan­ger­ous aster­oids close to Earth.

SpaceX launched a satel­lite June 3 with a new unfold­ing radio-trans­par­ent sun­shade to block sun­light from reach­ing bright sur­faces on the space­craft, such as its anten­nas. SpaceX says all Starlink satel­lites begin­ning with the space­craft on the launch Friday will carry the sun­shades.

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Follow Stephen Clark on Twitter: @StephenClark1.

Spaceflight Now source|articles

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