After a strangely quiet late summer and fall across Florida’s Space Coast—at least as far as launches are concerned—SpaceX ramped up the tempo earlier today (Thursday, 5 December) by staging its second Falcon 9 mission in less than three weeks. Hard on the heels of mid-November’s flight of 60 Starlink internet communications satellites, the Hawthorne, Calif.-headquartered company has successfully delivered the CRS-19 Dragon cargo ship towards the International Space Station (ISS).
Liftoff occurred on time at 12:29 p.m. EST, following a scrub on 4 Dec for unfavorable wind conditions, with Dragon scheduled to arrive at the orbital outpost early on Sunday, 8 Dec with 5,700 pounds of equipment, payloads and supplies for the incumbent Expedition 61 crew.
The Dragon for today’s mission was all about the reusability that SpaceX CEO Elon Musk has repeatedly stressed as his long-term intent. There was initial supposition that CRS-19 might ride the B1056 Falcon 9 first-stage, making a record-setting third ISS-bound flight, but it subsequently became clear that the brand-new B1059 core would pick up this mission instead.
Glistening with “newness”, B1059 and its equally sparkling second stage were trundled to SLC-40 last week and on 26 November completed a customary static fire test of the nine Merlin 1D+ first-stage engines. “Falcon 9 static fire test complete,” SpaceX tweeted late that evening. “Targeting December 4 launch from Pad 40 in Florida for Dragon’s nineteenth mission to the @Space_Station.”
However, the notion of “three-times-lucky” would not evade CRS-19 entirely. SpaceX announced that the mission would utilize the Dragon cargo ship serial numbered “C106”, which previously supported the CRS-4 flight in September 2014 and more recently CRS-11 in June 2017. When it completed its second voyage to the ISS, more than two years ago, it became the first Dragon to fly twice.
Sadly, C106 has since lost the opportunity to become first to fly three times. That crown went to its Dragon sister-ship C108, which flew CRS-6 in April 2015, CRS-13 in December 2017 and last July’s CRS-18. Yet with 64 days of flight time under its belt, C106 promises to another month to its in-space tally by the time it returns to Earth, sometime early in January.
CRS-19 is the second-to-last installment in SpaceX’s first-phase CRS1 Commercial Resupply Services contract with NASA, signed back in December 2008, which called for 12 Dragon cargo missions to the ISS. That total was subsequently revised to include three more flights added in 2015 and another five in 2016, with SpaceX selected as one of three finalists—alongside Northrop Grumman Corp. and Sierra Nevada Corp.—to provide follow-on CRS2 services in the 2019-2024 timeframe. SpaceX’s CRS1 commitment will conclude with its CRS-20 Dragon mission, early next spring, and its CRS2 round of flights is due to commence sometime later next year.
Following its static fire test, the 230-foot-tall (70-meter) Falcon 9 was returned to the Horizontal Integration Facility (HIF) at SLC-40 for the integration of Dragon at its tip. It was then returned to the pad in time for final pre-launch preparations.
Loading of liquid oxygen and highly refined rocket-grade kerosene (RP-1) got underway 35 minutes before the targeted T-0. The “instantaneous” launch window opened and closed at 12:29 p.m. EST, due to phasing requirements associated with reaching the ISS. Passing T-10 minutes, the terminal autosequencer was initiated and the Merlin 1D+ engines were chilled, ahead of ignition. At T-2 minutes, the Air Force Range Safety Officer verified that all ground-side assets were “Go for Launch” and the Falcon 9 transitioned to internal power and entered “Startup” at T-60 seconds.
Three seconds before the window opened, the nine Merlins roared to life, ramping up to 1.5 million pounds (680,000 kg) of thrust and B1059 kicked off its spacefaring career in fine style with an on-time liftoff. It burned for 2.5 minutes, before separating from the stack and commencing a multiple-burn descent back to alight on the deck of the Autonomous Spaceport Drone Ship (ASDS), “Of Course I Still Love You”, offshore in the Atlantic Ocean and successfully pulling of SpaceX’s 20th rocket landing.
Meanwhile, the Merlin 1D+ Vacuum engine of the Falcon 9’s second stage continued the push to insert CRS-19 into low-Earth orbit. During the course of its long burn, Dragon’s protective nose fairing was jettisoned to expose the berthing mechanism which it will use on Saturday, 7 December, to link up with the Earth-facing (or “nadir”) port of the space station’s Harmony node.
Current plans envisage a capture of CRS-19 by Expedition 61 Commander Luca Parmitano at around 6 a.m. EST Saturday, using the 57.7-foot-long (17.6-meter) Canadarm2. Backing up Parmitano in the station’s multi-windowed cupola will be NASA astronaut Drew Morgan, with fellow Expedition 61 crew member Jessica Meir monitoring telemetry during Dragon’s approach phase. Following capture, mission controllers will assume command of the arm, guiding the cargo ship to its berthing interface at Harmony nadir.
Housed in Dragon’s unpressurized “trunk” for CRS-19 is the 1,100-pound (500 kg) Hyperspectral Imager Suite (HISUI) instrument, provided by the Japan Aerospace Exploration Agency (JAXA). Shortly after the spacecraft arrives at the station, HISUI will be robotically extracted from the trunk and installed onto the Exposed Facility (EF) of Japan’s Kibo lab, where it will spend around three years observing the Home Planet at high resolution across all colors of the light spectrum, from visible to shortwave infrared.
In so doing, HISUI will afford an in-flight demonstration for future “hyperspectral” remote-sensing systems, which carries benefits from agriculture to forestry and from oil and gas exploration to understanding coastal erosion. HISUI has a long heritage, extending back to the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) aboard NASA’s 1999-launched Terra satellite.
The instrument will permit detailed inspections of rocks, soil, vegetation, snow and ice, as well as manmade objects to better understand their unique reflectance spectra. It will be plucked from Dragon’s trunk by the 57.7-foot-long (17.6-meter) Canadarm2 robotic arm, and handed off via the Dextre “hand” to the Kibo lab’s own robotic arm for installation in an Earth-facing (or “nadir”) orientation onto Port 8 of the EF. The HISUI data-storage system will be housed aboard the Kibo pressurized lab. Additionally, a limited quantity of HISUI data will be transmitted to ground stations in near-real-time. It is anticipated that up to 10 GB (equivalent to 18,000 square miles, or 30,000 square kilometers of ground coverage) will be downlinked daily, with a further 300 GB per day, roughly 560,000 square miles or 900,000 square kilometers, physically returned to Earth three or four times per year aboard Dragon cargo vehicles.
Although HISUI is perhaps the most visible aspect of the CRS-19 payload, a wide range of other investigations are packed aboard for Dragon’s ride uphill. All told, it is expected that some 7,300 pounds (3,310 kg) will be hauled to orbit on this mission, with an estimated 5,500 pounds (2,500 kg) returning to Earth in January 2020.
The Confined Combustion experiment will explore the behavior of flames as they spread in differently-shaped confined volumes. In the absence of gravity-driven buoyancy flows, the physics of flame spreading can be better observed in the microgravity environment of low-Earth orbit. Of particular interest are the upward spreading acceleration characteristic of flames. Recent SAFFIRE studies aboard Northrop Grumman Corp.’s Cygnus spacecraft revealed that flames tend to spread more slowly in large confined spaces than in smaller spaces, even if environmental conditions such as oxygen, pressure and flow speed are the same. By understanding flames behavior in confined volumes, numerical models can be developed to anticipate this kind of fire behavior in orbit, as well as leading to improved fire safety codes here on Earth. The experiment will utilize the Burning and Suppression of Solids (BASS) facility aboard the ISS.
Elsewhere, other investigations will study mice to better mitigate skeletal muscle and bone loss during space missions, while NASA’s Robotic External Leak Locator (RELL)—launched in 2015 and earlier this year—will gain a robotic tool storage docking station to allow RELL units to be stowed outside the station. As well as making the process of deploying the robotic leak sensor easier, the docking station will eliminate reliance upon crew time and airlock availability to move outside the pressurized hull of the ISS.
Other investigations flying on CRS-19 as part of the ISS National Lab’s sponsored payloads include an experiment from Budweiser, researching the effects of microgravity on the barley malting process.
It is expected that Dragon will remain aboard the station until early January.