In what’s become a rarity for SpaceX and its workhorse fleet of “flight-proven” hardware, a brand new Falcon 9 rocket and Dragon cargo capsule are scheduled to launch Thursday on a NASA-contracted flight to deliver more than 7,300 pounds of supplies and experiments to the International Space Station.
The two-day flight to the space station is set to begin at 1:29:15 p.m. EDT (1729:15 GMT) Thursday with a launch from pad 39A at NASA’s Kennedy Space Center in Florida. It will be SpaceX’s 22nd resupply mission to the International Space Station, and the company’s 17th launch of the year from Florida’s Space Coast.
There is a 60% chance of favorable weather for the mission’s instantaneous launch opportunity Thursday afternoon. The primary weather concern is with clouds and rain showers around the launch site.
Forecasters expect similar weather for a backup launch opportunity at 1:03 p.m. EDT (1703 GMT) Friday.
Unlike the previous 16 flights by Falcon 9 rockets since Jan. 1, the launch Thursday will debut a first stage booster fresh from SpaceX’s factory in Hawthorne, California. The booster is gleaming white, free of the dark charcoal color on the skin of previously-flown Falcon 9s.
Four years ago, SpaceX had only flown a reused rocket once. Now it’s flown 63 missions with reused first stages, more than half of the Falcon 9 rocket’s entire flight history.
“This is the 17th mission that SpaceX has launched just in this front half of 2021 … and the first one that’s on a new booster introducing a new booster to the fleet,” said Sarah Walker, SpaceX’s director of Dragon mission management. “We’re actually surprised when we get to a mission like today’s where we’re flying a new booster.”
The new booster, designated B1067 in SpaceX’s fleet, will attempt a landing on a SpaceX droneship in the Atlantic Ocean a few hundred miles northeast of the Kennedy Space Center. If all goes well, SpaceX and NASA plan to refurbish and refly the rocket on the next Crew Dragon flight to the space station in October.
The last time SpaceX flew a new Falcon 9 first stage was in November, when three consecutive missions launched with new boosters.
SpaceX and NASA agreed to not perform a test-firing of the new Falcon 9 booster on the launch pad. SpaceX fired up each of the rocket’s engines in standalone tests, then ignited all nine main engines on a test stand in McGregor, Texas, before shipping the stage to Florida for launch preparations.
SpaceX has skipped the static fire test before more than half of its Falcon 9 missions this year, but this mission marks the first time the company has not conducted the on-pad test-firing before a launch for NASA, or before a flight of a new booster.
The test-firing was a standard part of all SpaceX missions for most of the company’s history. But as of Wednesday, only six of the 16 Falcon 9 launches so far this year included pre-launch test-firings.
The company has countered the reduction in static fire tests with a more rapid launch cadence. Cutting out the static fire can cut the time between launches from the same pad by up to a few days.
For Thursday’s launch, the Falcon 9 rocket’s top end is crowned by a Cargo Dragon spacecraft, the second in a new generation of SpaceX supply ships derived from the human-rated Crew Dragon capsule designed for astronauts.
The new Cargo Dragon spacecraft design, which debuted with SpaceX’s previous resupply mission in December, can haul about 20 percent more cargo volume than previous Dragon cargo ships. The new cargo vehicle can stay at the space station for up to 75 days, more than twice as long as the first-generation Dragon spacecraft.
The Cargo Dragon, which splashes down off the coast of Florida at the end of each mission, can be used up to five times. That’s an improvement over the three-flight design of the first-generation Dragon cargo capsule. The new spacecraft can autonomously dock with the space station. Past Dragon cargo missions had to be captured by astronauts using the space station’s Canadian robot arm.
That change reduces the workload on the space station crew and makes the Cargo Dragon’s rendezvous profile nearly identical to the Crew Dragon, but the docking port used by the new Cargo Dragon has a narrower passageway than the connection used by the berthing system on the first-generation Dragon cargo capsule.
The first upgraded Cargo Dragon spaceship launched to the space station in December and returned to Earth in January. It’s now being refurbished for a future resupply mission. Like its rocket booster, the capsule on the Falcon 9 awaiting liftoff Thursday is a spaceflight rookie.
This mission is set to deliver experiments, food, spare parts, a NASA-sponsored CubeSat built by middle school students in Tennessee, and other equipment to the space station’s seven-person crew. The Dragon’s entire cargo load, including pressurized and unpressurized sections, weighs in at 7,337 pounds (3,328 kilograms).
That makes it the heaviest supply shipment SpaceX has ever sent to the space station. Northrop Grumman’s Cygnus supply freighters, which are designed for one flight each, can accommodate slightly heavier and more voluminous cargo.
Two new power-generating solar array wings for the space station are spooled on on cylindrical canisters and fastened inside the Dragon spacecraft’s rear trunk section. The ISS Roll-Out Solar Array, or iROSA, units weigh about 3,042 pounds (1,380 kilograms), according to NASA.
Assuming an on-time launch Thursday, the Cargo Dragon should dock with the top-facing port of the space station’s Harmony module at 5 a.m. EDT (0900 GMT) Saturday.
While astronauts open hatches and unpack the Dragon’s pressurized compartment, the space station’s Canadian-built robotic arm will reach into the capsule’s trunk and remove the two iROSA wings. The arm will transfer the solar arrays to a mounting bracket on the space station’s power truss, which stretches as long as a football field.
Astronauts Shane Kimbrough and Thomas Pesquet will venture outside the space station on two spacewalks scheduled for June 16 and June 20. The spacewalker will install the iROSA canisters before the wings deploy over top of a pair of existing solar arrays, unrolling like mats instead of unfolding like an accordion, the method employed by most conventional spacecraft solar panels.
“They come up rolled up,” said Joel Montalbano, NASA’s space station program manager at the Johnson Space Center in Houston. “Think of it like a Tootsie Roll, and they expand and then deploy.”
The roll-out arrays come with more efficient solar cells than the 20-year-old solar panels they will replace. Developed by Deployable Space Systems, a manufacturer recently acquired by the space infrastructure company Redwire, the roll-out arrays are half the size of the space station’s existing solar panels, but they generate roughly the same amount of electricity.
The space station’s eight original solar panels launched in pairs on four space shuttle missions in 2000, 2006, 2007, and 2009. The old arrays will remain on the station, but six will be partially covered by the new roll-out wings, canted at 10-degree angles to the original solar panels.
“Over time, the solar arrays on-board have degraded,” Montalbano said. “We celebrated 20 years of continuous human presence last year, and over time, just like any large home, you have to do upgrades and repairs.”
The upgraded arrays, coupled with residual power output from the old solar panels, will give the space station about 215 kilowatts of electrical power.
“These new solar arrays will put us at a power generation equal to when we first flew arrays on-board the International Space Station,” Montalbano said.
The added power generation capability will allow the space station to welcome a new commercial module developed by Axiom Space, and keep the complex running until at least 2030, officials said.
Four more iROSA wings are scheduled to launch on future Dragon cargo flights in 2022 and 2023. Similar roll-out solar arrays are in development for use on the planned Gateway mini-space station in orbit around the moon, part of NASA’s Artemis program to return astronauts to the lunar surface.
Other payloads aboard the Cargo Dragon spacecraft launching this week include biological experiments, technology demonstration hardware, spare part, food, and other provisions for the space station’s crew.
“This particular flight is going to bring up 37 investigations, and that is going to be a complement to the hundreds that we do every year on the ISS,” said Jennifer Buchli, NASA’s deputy chief scientist for the space station program.
One of the experiments will carry tardigrades, or water bears, to the space station to allow researchers to examine how the tiny animals withstand the stresses of spaceflight. Scientists have already shown tardigrades can survive extreme temperatures, pressures, radiation, and even in the vacuum of space.
The tardigrades launching this week will help scientists identify the genes involved in their adaptation and survival in high-stress environments, according to NASA. The resilient animals will return to Earth for scientists to study. Researchers hope the results could aid in the understanding of the stress factors affecting humans in space, NASA said.
“We’re using these animals because they’re some of the toughest animals we know of,” said Thomas Boothby, a professor of molecular biology at the University of Wyoming, and chief scientist on the tardigrade investigation.
Another research payload will focus on how spaceflight impacts interactions between biologically beneficial microbes and their animal hosts.
“Beneficial microbes play a significant role in the normal development of animal tissues and in maintaining human health, but gravity’s role in shaping these interactions is not well understood,” NASA said in a press kit for the Cargo Dragon mission. “This experiment could support the development of measures to preserve astronaut health and identify ways to protect and enhance these relationships for better wellbeing on Earth.”
The experiment, named UMAMI, will examine the relationship between young bobtail squid specimens and symbiotic bacteria, which will be introduced to the squid once in space.
Other experiments awaiting launch Thursday include a payload to study the growth of cotton plant roots in microgravity, which could lead to development of cotton varieties on Earth that require less water and fewer pesticides, according to NASA.
The Cargo Dragon will also haul a catalytic reactor for the space station’s water generation system, hardware for an emergency breathing system for the station astronauts, and an electronics unit for a Russian remote-control docking system for visiting Progress cargo spacecraft.
Here’s a breakdown of the cargo launching on the SpaceX resupply mission:
- ISS Roll-Out Solar Arrays: 3,042 pounds (1,380 kilograms)
- Science Investigations: 2,028 pounds (920 kilograms)
- Vehicle Hardware: 760 pounds (345 kilograms)
- Crew Supplies: 751 pounds (341 kilograms)
- Computer Resources: 129 pounds (58 kilograms)
- Spacewalk Equipment: 115 pounds (52 kilograms)
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