SpaceX to launch first Starlink rideshare mission with Planet Labs

As SpaceX continues to roll through its 2020 launch campaign, the company is preparing to launch another batch of Starlink internet satellites to low Earth orbit, along with 3 small satellites provided by Planet Labs Inc. The mission is currently set to launch on a flight-proven Falcon 9 rocket from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida on Saturday morning at 5:21 am Eastern time (09:21 UTC).

Saturday’s mission, known as Starlink V1.0 L8, will be the ninth orbital launch of the year for SpaceX to date, and the 87th flight of the two-stage Falcon 9 since its maiden launch in June 2010. This will also be the 42nd orbital launch attempt made by any launch provider in 2020.

The first stage of the Falcon 9 rocket that will launch Saturday’s mission is core B1059.3. This designation originates from SpaceX’s internal booster naming/numbering scheme, with B1059 being the 59th Falcon 9/Heavy booster core built by the company at their headquarters in Hawthorne, California, and the “.3” signifying that the booster has been configured for its third flight.

Falcon core B1059 launches the 19th Dragon cargo resupply mission to the ISS – credit: Brady Kenniston for NSF/L2

B1059 previously launched the CRS-19 and CRS-20 Dragon cargo resupply missions to the International Space Station in December 2019 and March 2020, respectively. During both missions, the booster performed a successful propulsive landing at SpaceX’s Landing Zone-1 at Cape Canaveral Air Force Station. B1059 will attempt to land on the droneship “Of Course I Still Love You” during the Starlink V1.0 L8 mission.

This mission will be the first for SpaceX’s SmallSat Rideshare Mission program, which aims to provide a flexible, low-cost method of transporting multiple small satellites to an assortment of destinations in low Earth orbit using Falcon 9 launch vehicles. SpaceX announced the creation of the program in August 2019, and allowed small satellite operators to begin manifesting their spacecraft to launch on dedicated rideshare flights or select Starlink missions.

Since the announcement, companies such as Planet Labs, Exolaunch, and Momentus Space have signed contracts with SpaceX to launch on rideshare missions. The first fully-dedicated SmallSat Rideshare Mission program flight is currently scheduled to launch no earlier than December from Space Launch Complex 4E at Vandenberg Air Force Base in California.

In total, 61 satellites will be flying on Saturday’s mission: 58 SpaceX-built Starlink internet satellites and 3 SkySat Earth observation spacecraft, which are owned and operated by Planet Labs of San Francisco, California.

The Starlink V1.0 L8 mission will be the eighth operational launch of Starlink satellites to date, with a total of 480 spacecraft launched as part of the initial deployment phase of SpaceX’s satellite internet constellation. This first phase will see 1,584 Starlink satellites launched over multiple missions, with additional deployment phases and satellite launches to follow.

Thanks in part to the rapid growth of the operational V1.0 constellation, SpaceX will begin private beta testing of the Starlink internet service in select areas around the globe later this summer, with public beta testing set to begin soon after. Updates on beta testing will be provided on the company’s website.

Each Starlink satellite features a flat-panel design with multiple high-throughput phased array antennas, a single solar panel for on-orbit power generation, and a star tracker navigation system. A single Krypton-fueled Hall-effect thruster is equipped for in-space propulsion, and is used for orbit raising maneuvers and deorbit burns.

Artistic render of a Starlink satellite using a visor to block incoming sunlight while on orbit – Credit: SpaceX

As was the case with a single Starlink satellite on the V1.0 L7 mission (launched on June 4), all Starlink satellites that will launch on the V1.0 L8 mission – and subsequent missions going forward – will also feature a sun shade or visor, which will assist in blocking sunlight from reflecting off of the majority of the spacecraft body while in orbit and reducing its overall albedo/intrinsic brightness as observed from the ground. These visors will deploy shortly after spacecraft separation during Saturday’s launch.

Each operational Starlink satellite weighs in at approximately 260 kilograms (573 pounds) at launch.

The SkySat satellites are built by Maxar Technologies, and are designed to capture high resolution panochromatic and multispectral images of Earth via the use of a 3.6 meter focal length Cassegrain telescope and three 5.5 megapixel CMOS (complementary metal oxide semiconductor) imaging detectors on each spacecraft, thereby enabling an image resolution of less than 50 centimeters. The SkySats are also outfitted with a modular propulsion system utilizing “green propellants”, which are intended to be less toxic and more efficient when used for in-space maneuvers.

Artist’s impression of the SkySat satellite fleet in orbit – credit: Maxar

Fifteen Planet SkySat satellites have been launched to date, with the first two spacecraft serving as prototypes. Both were launched in November 2013 and July 2014 as secondary payloads on Dnepr and Soyuz rockets, respectively. The other thirteen operational satellites have been launched to 500 kilometer (310.6 mile) sun-synchronous orbits, having flown on ISRO’s Polar Satellite Launch Vehicle (PSLV), Arianespace’s Vega, Northrop Grumman’s Minotaur-C, and SpaceX’s Falcon 9 over a four-year period.

SpaceX has launched many satellites for Planet over the years, with multiple Dove nanosatellites flying on Falcon 9 rockets and Dragon spacecraft, and two other SkySat spacecraft (SkySats 14 and 15) having launched on the SSO-A mission in December 2018.

SpaceX will be launching three SkySat spacecraft (SkySats 16, 17, and 18) on the Starlink V1.0 L8 mission, with another three satellites (SkySats 19, 20, and 21) flying on another Starlink mission later in the year. These six satellites will complement the existing SkySat fleet in sun-synchronous orbit and offer more targeted coverage in key geographic regions.

Each operational SkySat spacecraft weighs around 110 kilograms (242.5 pounds) at liftoff. When combined with the mass of the 58 Starlink satellites that will fly on Saturday’s mission, the total launch mass rounds up to 15,410 kilograms (33,973 pounds).

The three SkySat satellites will be mounted on top of the Starlink payload during the V1.0 L8 mission, with a custom adapter provided by Planet Labs housing the trio until spacecraft separation.

The Starlink V1.0 L8 mission is currently set to launch no earlier than 5:21 am Eastern time Saturday (09:21 UTC) from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida. A backup launch opportunity is available on Sunday at 4:59 am Eastern (08:59 UTC) in the event of a delay or scrub.

This mission will go into the books as the 37th Falcon 9 launch from SLC-40, and the 99th total launch from the site since its debut in June 1965, which saw the maiden flight of the Titan IIIC launch vehicle take place.

Unlike all previous SpaceX missions to date, the company has elected to forego a pre-flight static fire attempt on the pad with Falcon core B1059.3 for this mission. A static fire acts as a readiness test before launch, as the first stage engines are ignited and fired for a short duration in order to obtain performance data and verify that the engines will perform nominally during flight.

The Falcon 9 rocket and its 61 satellites were lifted to the vertical position at SLC-40 on Friday afternoon, just over 12 hours before the scheduled launch time.

The countdown will officially commence at the T-38 minute mark, when the launch director will poll the mission teams to proceed into propellant loading operations. When the “go” is given, chilled RP-1 fuel will begin flowing into both stages of the Falcon 9 launch vehicle at 35 minutes to liftoff, along with liquid oxygen (LOX) loading into the first stage. LOX loading onto Falcon 9’s second stage will start at T-16 minutes.

At T-7 minutes prior to liftoff, the liquid oxygen pre-valves on the nine Merlin-1D first stage engines will open, thereby allowing LOX to flow through the engine plumbing and condition the turbopumps for ignition. This process is known as “engine chilling”, and is used to prevent thermal shock that could damage the motors upon startup.

At the T-1 minute mark, the Falcon 9’s onboard flight computers will run through final checks of the vehicle’s systems and finalize tank pressurization before flight. Pending any issues that arise before this point, the launch director will give a final “go” for launch at T-45 seconds.

The nine Merlin-1D engines on the first stage will ignite at T-3 seconds, with liftoff taking place at T-0 following a quick final check by the onboard computers to verify that all systems are operating nominally.

After lifting off from SLC-40, Falcon 9 will begin pitching downrange as it accelerates towards orbital velocity. At around a minute and 12 seconds into the flight, the vehicle will pass through the region of maximum aerodynamic pressure, or “Max-Q”. During this portion of flight, the mechanical stresses on the rocket and payload are at their highest.

Planned mission profile for a Falcon 9 launch and droneship landing – credit: SpaceX

The nine Merlin-1D engines on Falcon 9’s first stage will continue to burn until around T+2 minutes and 32 seconds, at which point they will all shut down simultaneously in an event known as MECO, or Main Engine Cutoff. Stage separation will occur shortly afterward, with second stage Merlin Vacuum engine ignition taking place at the T+2 minute 43 second mark. Upon engine startup, the second stage will continue to carry all 61 satellites to a low Earth orbit, with an inclination of 53 degrees.

The 5-meter payload fairing that will house the payloads during the initial phases of launch will deploy at approximately 3 minutes and 11 seconds into the flight. Both halves of the fairing will descend back to Earth to be recovered by GO Ms. Tree and GO Ms. Chief, SpaceX’s fairing recovery vessel duo. These recovery attempts will occur at around 45 minutes after liftoff.

The two halves of the payload fairing that will fly on the Starlink V1.0 L8 mission have flown once before on separate missions, with one half flying on the JCSAT-18/Kacific 1 mission in December 2019, and the other having launched on the Starlink V1.0 L2 mission in January 2020. During both missions, the fairing halves were recovered after performing a soft splashdown in the Atlantic Ocean.

While Falcon 9’s second stage and the 61 satellites continue to press onward to orbit, Falcon core B1059.3 will begin to return to Earth to conduct a propulsive landing on the droneship “Of Course I Still Love You”, stationed approximately 630 kilometers (391.4 miles) downrange from the launch site.

Falcon core B1059 performing a soft landing after successfully launching CRS-20 to orbit – Credit: SpaceX

The first stage will perform an entry burn at around 7 minutes into the flight, in order to slow its descent and refine its trajectory to the droneship. The final landing burn is expected to be completed at the T+8 minute 42 second mark, with B1059.3 touching down softly on the deck of OCISLY under the power from a single Merlin-1D engine.

The Merlin Vaccum engine on Falcon 9’s second stage will shut down at 8 minutes and 53 seconds into the flight, in an event known as SECO, or Second Engine Cutoff. This will be the only second stage engine burn of the mission.

Payload deployment will begin at around the T+12 minute 34 second mark, when the SkySat-18 spacecraft will separate from its payload adapter. Subsequent SkySat deployment events will occur at 30 second intervals.

At approximately 26 minutes into the mission, the 58 Starlink satellites will be deployed. This will mark the completion of the launch phase of the mission.

At this point, SpaceX will begin conducting data reviews of each Starlink satellite to ensure that all systems are working as intended before proceeding to orbit raising operations. Any satellites that are unable to raise their orbits will be left in the initial deployment orbit, so as to quickly deorbit and decrease the risk of a collision.

The Starlink V1.0 L8 mission will be the second launch for SpaceX in June 2020, with two more missions scheduled to follow shortly afterward. The ninth operational Starlink mission (which will also feature two BlackSky Earth observation satellites provided by Spaceflight, Inc.) is currently set to launch on a Falcon 9 no earlier than June 22 from Launch Complex 39A at the Kennedy Space Center, while another Falcon 9 will launch the third GPS Block III spacecraft to a medium Earth orbit no earlier than June 30 from SLC-40 at Cape Canaveral.

In the long-term, SpaceX plans to launch the Anasis-II spacecraft for the South Korean military to orbit no earlier than July. The launch will take place from Launch Complex 39A at KSC.

SpaceX aims to launch at least 24 operational Starlink missions before the end of 2020.

The post SpaceX to launch first Starlink rideshare mission with Planet Labs appeared first on NASASpaceFlight.com.



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