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COLORADO SPRINGS—Sierra Space has announced pharmaceutical giant Merck as its first commercial rideshare partner for the inaugural flight of the Dream Chaser spaceplane on a NASA mission later this year.
The Merck payload, which will be an experiment focused on the development of cancer treatments, is one of several due to be carried to the International Space Station (ISS) along with NASA supplies for the astronauts working in orbit.
Merck is among several pharma companies researching breakthrough medical drugs in microgravity and has previously carried experiments to and from the ISS onboard the space shuttle and SpaceX’s Dragon. However, Paul Reichert, Merck principal investigator, says a key part of the appeal of the Dream Chaser will be its ability to “bring samples back very gently,” and return from orbit to a runway landing—just as the space shuttle did.
The Dream Chaser is designed to reenter at fewer than 1.5g, and—after landing—provide rapid access to unload critical cargo, which Merck sees as a key advantage when dealing with sensitive biopharma materials. The experiment will be mounted on a Merck Formulation Research Platform, which was developed in collaboration with the Merck 3D Printing Department and Sierra Space.
“One of the big issues for delivering biologics is their high viscosity and the need to deliver high concentrations of material or large volumes of concentration. So, we're looking at opportunities to make crystalline and amorphous suspensions that can be given as a subcutaneous injection rather than as an intravenous infusion,” Reichert says.
Microgravity research is targeting the development of high-concentration amorphous suspensions that would enable the delivery of cancer-fighting and other drugs with a syringe just like vaccines and other medications. “This would significantly impact the quality of life for the patients, as well as the caregivers,” Reichert says.
“We're also hoping that these formulations will have room-temperature stability. One of the big issues with biologics is that they have to be refrigerated. So we're looking at whether with these concentrated suspensions we can maintain stability for months at a time, because there are parts of the globe where you don't have stable refrigeration conditions.”
The planned higher mission cadence of Dream Chaser will therefore also be a bonus to the researchers, he adds. “One of the things that has slowed advances in microgravity research is not having the ability to do iterative experiments. Tenacity [the initial Dream Chaser] gives us an opportunity to do multiple follow-up experiments in a more reasonable period of time. Right now, it may take over a year to prepare an experiment, to go through the approval process and everything else,” Reichert says.
Ken Shields, senior director in Sierra Space’s business development group, says as well as the lower G reentry of the Dream Chaser’s lifting body versus the ballistic entry of a spacecraft, the ride through the denser atmosphere will be gentler for the payload because there is no sudden load from the opening of the brake parachutes used by capsules.
“You get this huge shock from the parachute, which a lot of folks don't understand, but it is significant. Both of those loads are very hard to account for from a variable perspective, and what you're predicting in your baseline. Your modeling is very wide, so again, it is hard to control that variable,” Shields says.
Unloading the payload into an enclosed facility after landing will also reduce variability and ensure the safety of fragile samples, he adds. “These precious materials are now being recovered in a highly controlled environment, as opposed to a heavy landing in an ocean or on a desert. Then you potentially have to go through several other handling processes, and a lot of other variables go into it.”
The Dream Chaser recently completed a series of payload integration tests at NASA’s Kennedy Space Center in Florida dubbed the Joint Test 10B milestone, which demonstrated the spaceplane’s ability to power on, air-cool and exchange data with multiple powered payloads inside its pressurized cabin.
As the initial flight is a commercial resupply mission under contract with NASA, “they essentially own the mission, and they own the scheduling,” Shields says. “Right now, we are in their flight program, and it's looking like the fall of this year. Our goal is to have the vehicle, the entire system, ready to go to flight early this summer. Then we’ll be ready to go start our vertical integration on the launch vehicle whenever NASA is ready to pull the trigger,” he adds.
Originally due to be launched in 2024, the spaceplane’s debut was previously scheduled to take place no earlier than May on a United Launch Alliance Vulcan Centaur vehicle.
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