SpaceX cargo ship launches on mission to upgrade space station electrical grid

June 3, 2021 Stephen Clark
Nine Merlin main engines propel a SpaceX Falcon 9 rocket into the sky over the Kennedy Space Center on Thursday. Credit: Stephen Clark / Spaceflight Now

Trailing a brilliant orange flame, a SpaceX Falcon 9 rocket thundered into orbit Thursday from the Kennedy Space Center in Florida with a Dragon cargo ship hauling experiments and new solar arrays to enhance the International Space Station’s power generation capability.

The 215-foot-tall (65-meter) rocket launched from pad 39A, the same location where Apollo moon missions took off, at 1:29:15 p.m. EDT (1729:15 GMT) Thursday, taking advantage of a break in rain showers streaming across Florida’s Space Coast.

Nine powerful Merlin 1D main engines propelled the launcher off the pad and steered the Falcon 9 on a trajectory to the northeast from the Florida spaceport, lining up with the space station’s orbital plane to begin the Dragon capsule’s high-speed pursuit of the research outpost.

The Falcon 9 soared through broken clouds over the space center, letting out a deep rumble as it headed into orbit.

Two-and-a-half minutes after liftoff, the rocket’s first stage booster shut down and began maneuvers to return to a landing on a SpaceX drone ship parked in the Atlantic Ocean more than 180 miles (300 kilometers) downrange from Cape Canaveral.

The brand new 15-story booster completed its first trip to space with a successful landing on the deck of the football field-sized drone ship, which will bring the rocket back to Cape Canaveral for refurbishment. SpaceX plans to use the rocket again on the next launch of a Crew Dragon spaceship with NASA astronauts in October.

About a minute after the first stage landed, the Falcon 9’s second stage engine cut off after placing the Cargo Dragon spacecraft into orbit. The supply ship deployed from the rocket about 12 minutes into the mission, and opened its nose cone moments later to reveal a docking port that will link up with the space station.

A series of firings using the Dragon’s Draco thrusters over the next day-and-a-half will set up for a final approach to the space station early Saturday.

After lining up with its docking target, the Cargo Dragon will move in to link up with the space-facing port of the space station’s Harmony module at 5 a.m. EDT (0900 GMT) Saturday.

The picture-perfect launch Wednesday was SpaceX’s 17th flight of a Falcon 9 rocket since Jan. 1, a record pace for any U.S. rocket company. SpaceX is preparing another Falcon 9 rocket for launch from Cape Canaveral Space Force Station early Sunday with the SXM 8 radio broadcasting satellite for SiriusXM.

This mission is SpaceX’s 22nd cargo resupply flight to the space station under contract to NASA, and the second to use a new generation of Dragon cargo freighters derived from SpaceX’s human-rated Crew Dragon spacecraft.

Unlike the previous 16 flights by Falcon 9 rockets this year, the launch Thursday debuted a first stage booster fresh from SpaceX’s factory in Hawthorne, California. Before Thursday’s fiery blastoff, the booster was 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.”

SpaceX’s Falcon 9 rocket climbs into the sky over NASA’s Kennedy Space Center to begin the company’s 22nd cargo mission to the International Space Station. Credit: Stephen Clark / Spaceflight Now

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 that launched Thursday was on its first voyage into space.

SpaceX’s 22nd commercial resupply 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, adds up to 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 cylindrical canisters and fastened inside the Dragon spacecraft’s rear trunk section. The ISS Roll-Out Solar Array, or iROSA, units weighed about 3,042 pounds (1,380 kilograms) at launch, according to NASA.

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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 two Dragon cargo flights in 2022. 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 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 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 launched 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 is also hauling 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 on the SpaceX CRS-22 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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