Poor weather conditions Saturday prompted SpaceX to delay its planned launch from Kennedy Space Center to the International Space Station, so now it’s actually the second scheduled Space Coast flight on Sunday.
The company has a scheduled Starlink launch from nearby Cape Canaveral on Sunday morning, which would then be followed by the company’s 28th cargo resupply mission from KSC after noon, although the weather forecast for both of those launches could force yet more delays.
First up would be a Falcon 9 from Canaveral’s Space Launch Complex 40 sending up 22 of SpaceX’s second-generation Starlink internet satellites. Liftoff is targeted for 5:56 a.m. with backup opportunities that morning at 6:49 a.m., 7:36 a.m. and 8:30 a.m. If delayed until Monday, the launch opportunities come at 5:33 a.m., 6:23 a.m., 7:14 a.m. and 8:04 a.m.
Space Launch Delta 45’s weather squadron’s forecast, though, gives Sunday only a 50% chance for favorable launch conditions with a similar threat of thunderstorms that have been present all week with excess moisture flowing in from Tropical Storm Arlene off Florida’s coast in the Gulf of Mexico. A Monday delay would see conditions worsen to 40% chances for good launch weather.
If it does launch, the first-stage booster would be making its third flight and the company will attempt a recovery landing down range on its droneship Just Read the Instructions in the Atlantic.
A few hours later is SpaceX’s chance to fly a Falcon 9 from KSC’s Launch Pad 39-A at 12:12 p.m. with a cargo Dragon spacecraft carrying nearly 7,000 pounds of supplies and science experiments. A one-day delay has an 11:47 a.m. liftoff target Monday.
SLD 45’s weather squadron forecasts similar odds for good conditions with only 40% chance on Sunday, raising to 60% Monday and 90% if delayed until Tuesday.
If CRS-28 does launch, the first-stage booster will be making its fifth flight with SpaceX looking to recover it again down range on its droneship A Shortfall of Gravitas in the Atlantic. The cargo Dragon is making its fourth trip to space, and would dock on Tuesday morning with the ISS.
A big chunk of the weight flying in Dragon comes from the last pair of six new ISS Roll Out Solar Arrays, or iROSAs, that will be installed during a pair of spacewalks later this month. The $103 million replacements for the station’s existing arrays that have been used since 2000 will supply 30% more power and help ensure the station can be operational through NASA’s planned 2030 retirement.
Also headed up is more food for the seven crew members on board including fresh apples, blueberries, grapefruit, oranges, cheese and tomatoes.
“SpaceX 28 launch brings a great mix of payloads to add to the over 3,700 investigations flown to the ISS to date,” said Dr. Kirt Costello, chief scientist for the International Space Station Program Research Office during a conference call Friday. He noted 31 investigations for NASA and international partners are making the trip up this time.
One of the science investigations he highlighted looks at plant genetics, headed up by University of Florida researchers Anna-Lisa Paul and Robert Ferl. It involves the seeds collected from plants that were grown in space and brought back to Earth just this past April on the return flight of SpaceX CRS-27. These seeds were then planted and are now headed back to space.
“This investigation — Plant Habitat-03 — is probably our most complex mission to date,” Costello said. “Not only because it involves multiple flights where we have to grow out the plant on orbit, take samples and then prep them on the ground for re-flight, but because it’s really looking at the genetic nature of how life responds to the microgravity environment, and stress that’s created from living in that environment.”
The benefits could involve how to grow plants for multiple generations in space, but could also be used to help adapt plant life in challenging habitats on Earth, he said.
“It’s a very ambitious investigation, also one that really gets at the nature of what it means to live in a microgravity environment,” Costello said. “So for that reason, it stands out as one of our most complex and most ambitious missions.”
Another investigation run by the European Space Agency is called Thor-Davis, which will observe thunderstorms from the ISS.
“Thor Davis is looking for upward-directed lightning events over the tops of thunderclouds,” Costello said. “So the ISS is a perfect vantage point for these kinds of observations. They’ll be using an electronic combination with a camera from a nadir window to capture what are known as blue jet and other lightning phenomenon.”
A genetic experiment that was spearheaded by Boeing working with students from grades 7-12 will pick up where the year-in-space twin study involving former astronauts Mark and Scott Kelly left off. It looks to measure gene structures called telomeres that protect human chromosomes, but shorten with age and wear. In the Kelly twin study, these telomeres were only able to be measured while Scott Kelly was on Earth and not during his yearlong stay on the station. This study looks to measure them while on orbit.
“Understanding the mechanism behind telomere lengthening could reveal possible effects on astronaut health during long-term missions,” according to a NASA press release. “Results also could lay the groundwork for a variety of related research to benefit future space travel and people on the ground.”
Also headed up are a pair of small satellites for ISS partners, the Canadian Space Agency. They will be sent out into orbit from the ISS via the Nanoracks CubeSat Deployer on board. One called Nanoracks-ESSENCE, which stands for Educational Space Science and ENgineering CubeSat Experiment Mission, will look at solar storms, Arctic ice, permafrost thaw and forests in the Canadian Arctic, looking to measure the effects of climate change.
Another called Nanoracks-Iris has geological samples on board that will orbit the Earth for months to measure the effects of direct solar or background cosmic radiation.
“Results could provide insight into similar processes on planetary bodies and, when combined with data from asteroid sampling missions, improve understanding of the origins of asteroids,” NASA’s press release said.
The cargo Dragon will remain attached for about three weeks to the ISS’s Zenith port alongside the Crew Dragon Endeavour that brought up the Crew-6 astronauts in March. They won’t return until Crew-7’s launch currently targeting mid-August.
The two Space Coast launches would be the 27th and 28th of the year from either KSC or Canaveral, with all but one coming from SpaceX. Including California launches, SpaceX will have flown 38 orbital missions not including its Starship and Super Heavy attempt from Texas.