SpaceX will wait until tomorrow morning to launch the greatest number of individual satellites ever flown aboard a U.S. launch vehicle, following Saturday morning’s postponement of the Transporter-1 mission aboard a previously-flown Falcon 9 booster. “Due to unfavorable weather, we are standing down from today’s launch,” SpaceX noted. “The team will continue with the countdown until T-30 seconds for data collection.”
B1058 rises on 30 May for its maiden voyage, carrying Dragon Endeavour crewmen Doug Hurley and Bob Behnken to the International Space Station (ISS). Photo Credit: Mike Killian/AmericaSpace
Liftoff of the Hawthorne, Calif.-headquartered organization’s third mission of 2021 will occur from storied Space Launch Complex (SLC)-40 at Cape Canaveral Space Force Station, Fla., no sooner than 10 a.m. EST Sunday. The B1058 booster core—which is set to become only the fifth Falcon 9 to attempt a fifth launch—will deploy 143 discrete payloads, including the first ten Starlink internet communications satellites bound for polar orbit.
The weather outlook along the Space Coast for Saturday was iffy at best, with barely a 60-percent chance of acceptable conditions at T-0, although that is expected to improve to 70 percent on Sunday and 80 percent by Monday.
The 230-foot-tall (70-meter) Falcon 9 was trundled out to the pad and raised to the vertical on SLC-40 yesterday, ahead of this weekend’s attempts to get the third SpaceX mission of 2021 airborne. And if B1058 flies tomorrow—her nine Merlin 1D+ first-stage engines punching out 1.5 million pounds (680,000 kg) of thrust at liftoff—she will become the fifth Falcon 9 core to log a fifth mission. In flying so often, she has already set “personal-best” records for SpaceX for the shortest amount of time it has taken a single booster to fly two, three, four and five times to orbit.
As of tomorrow morning, a mere 239 days will have elapsed since B1058 set off on her maiden voyage with NASA astronauts Doug Hurley and Bob Behnken aboard Dragon Endeavour for their historic voyage to the International Space Station (ISS). In doing so, she will neatly surpass the Falcon 9 fleet leader B1051, which holds the current record of having flown her most recent five missions in just 273 days.
In launching Hurley and Behnken last 30 May, B1058 helped to realize the promise of the Commercial Crew Program to return U.S. astronauts to space, aboard U.S. rockets, and from U.S. soil, for the first time in nine years, since the end of the Space Shuttle era. Following a smooth launch and return to the deck of the Autonomous Spaceport Drone Ship (ASDS), “Of Course I Still Love You”, she was reprocessed for a second launch on 20 July, during which she lifted South Korea’s ANASIS-II military communications satellite to orbit.
Third and fourth flights followed in rapid order. B1058 deployed 60 Starlink low-orbiting internet communications satellites into space on the morning of 6 October—helping to break the curse of an already delay-prone “Scrubtober” on the Space Coast—and set a record for the shortest interval (only 129 days) between three launches by the same booster. On 6 December, she recorded the 100th fully-successful mission by a member of the Falcon 9 rocket family and the shortest interval (only 190 days) between four launches by the same booster, when she boosted the CRS-21 Dragon cargo ship to the space station.
Principal payload for tomorrow’s flight is Transporter-1, which marks SpaceX’s first dedicated SmallSat Rideshare Program Mission and whose 143-strong cargo of small satellites originate from a multitude of commercial and U.S. Government entities. Ten of those payloads are easily recognizable—a smaller-than-usual batch of Starlink internet communications satellites, uniquely bound for polar orbit—whilst the other 133 CubeSats, microsats and orbital transfer vehicles are assigned a range of quite different scientific and technical objectives.
Among their number are several Synthetic Aperture Radar (SAR) instruments for Earth observations, together with small satellites tasked with weather and climate monitoring, the measurement of aerosol pollutants and other “greenhouse gases” and student-led investigations into terrestrial, ionospheric and solar physics.
Multiple technology demonstrators will ride Transporter-1, ranging from optical communications systems to autonomous formation-flying satellites and from rendezvous and proximity operations to assessing the effects of atomic oxygen on spacecraft components. And the contributors to Transporter-1 are international in their depth and breadth, spanning students and research teams from the United States to Germany, from Finland to Canada, from Italy to Taiwan and from Switzerland to Japan.
Taking pride of place on Transporter-1 is the first SHERPA-FX commercial satellite dispenser, officially unveiled last summer and provided by Seattle, Wash.-headquartered smallsat launch provider Spaceflight, Inc. An earlier variant of the SHERPA was used on the firm’s first dedicated rideshare mission with SpaceX, the SSO-A SmallSat Express, launched out of Vandenberg Air Force Base, Calif., with a record-breaking 64 discrete payloads, back in December 2018. SSO-A represented the largest quantity of smallsats ever launched by a U.S. rocket at that time.
But a new generation of SHERPAs—the first of which flew today—carry a far broader range of capabilities, acting as an Orbital Transfer Vehicle (OTV) and effectively providing the Falcon 9 with a third stage. With a total spacecraft mass of around 850 pounds (385 kg), SHERPA-FX has the functionality to physically separate from the second stage of the rocket, using its own integrated avionics, before initially any of its smallsat deployments. “The vehicle,” noted Spaceflight, Inc., “is capable of executing multiple deployments, providing independent and detailed deployment telemetry and flexible interfaces.”
Last June, Spaceflight, Inc., and SpaceX signed a Multi-Launch Agreement to secure capacity on “several” Falcon 9 missions, due to launch through late 2021. It was stressed by Spaceflight, Inc. President Curt Blake that the “consistent launch schedule” demonstrated by the SpaceX Falcon 9 fleet would enable the provision of more reliable and less expensive rideshare options for commercial clients. According to Spaceflight, Inc., a total of 16 of its payloads—of which 15 will ride the SHERPA-FX—flew on Saturday’s mission, in what has variously been described as “Transporter-1” or “Smallsat Rideshare Mission-1”.
Assuming a successful launch tomorrow morning, the opening minutes of the mission will proceed like another Falcon 9 flight. B1058 will power the first phase of ascent, before separating and returning to a landing on the Autonomous Spaceport Drone Ship (ASDS), “Of Course I Still Love You”, situated offshore in the Atlantic Ocean. The second stage will then burn its Merlin 1D+ Vacuum engine for a further six minutes, before shutting down.
And following a lengthy period of coasting flight and a final “circularization” burn by the second stage, the process of deploying Transporter-1’s huge haul of payloads will begin. This will occur over a 33-minute period, starting with a batch of Earth-imaging satellites for San Francisco, Calif.-headquartered Planet Labs, Inc., and ending with SpaceX’s latest instalment of homegrown Starlinks.