NASA cancels Sierra Space’s contract for Dream Chaser cargo missions to ISS

Tenacity grounded in a warehouse
Tenacity grounded in a warehouse, with the
Shooting Star small cargo capsule attached to
its aft port.

NASA today announced it has modified its fixed-price cargo contract with Sierra Space, canceling the planned seven cargo missions as well as a demo docking mission, replacing this with one test flight that will simply go into orbit and then return to Earth.

After a thorough evaluation, NASA and Sierra Space have mutually agreed to modify the contract as the company determined Dream Chaser development is best served by a free flight demonstration, targeted in late 2026. Sierra Space will continue providing insight to NASA into the development of Dream Chaser, including through the flight demonstration. NASA will provide minimal support through the remainder of the development and the flight demonstration. As part of the modification, NASA is no longer obligated for a specific number of resupply missions, however, the agency may order Dream Chaser resupply flights to the space station from Sierra Space following a successful free flight as part of its current contract.

The first launch of Tenacity, the only Dream Chaser so far constructed, has been repeatedly delayed for the past two years, with no explanation from either the company or NASA. Those delays started in 2023 as engineers began the final ground testing before launch, so though we do not know what the issue is it is likely that testing found something fundamentally wrong with the spacecraft that Sierra could not afford to fix.

According to Sierra’s own press release, the company will target a late 2026 launch for that free flyer mission. The company still hopes that mission will make further flights possible, either purchased by NASA or by others wishing to use Tenacity for in-orbit manufacturing, something it first proposed last year.

In the past two years, Sierra has shifted its focus away from commercial manned space and more towards winning military defense contracts. Part of that decision might have come from the problems with Dream Chaser. The decision might have also been fueled by the company’s generally unsatisfactory experience working with Blue Origin on their proposed Orbital Reef space station. While Sierra committed cash to develop and test its LIFE inflatable module, including a full scale prototype, Blue Origin appeared to do nothing at all. As early as September 2023 there were rumors the partnership was falling apart.

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ISS research suggests weightlessness accelerates aging in stem cells

According to a study that flew stem cells on four separate missions to ISS ranging in length from 32 to 45 days, weightlessness appears to age stem cells significantly.

Researchers from University of California San Diego Sanford Stem Cell Institute have discovered that spaceflight accelerates the aging of human hematopoietic stem and progenitor cells (HSPCs), which are vital for blood and immune system health. In a study published in Cell Stem Cell, the team used automated artificial intelligence (AI)-driven stem cell-tracking nanobioreactor systems in four SpaceX Commercial Resupply Services missions to the International Space Station (ISS) to track stem cell changes in real time. The findings show that the cells lost some of their ability to make healthy new cells, became more prone to DNA damage and showed signs of faster aging at the ends of their chromosomes after spaceflight — all signs of accelerated aging.

Upon return to Earth the study also found the cells recovered somewhat.

You can read the peer-reviewed paper here.

In a sense, this study confirms what numerous other research has found, that weightlessness mimics the conditions of old age, and causes the same physical decline seen in the elderly. It also shows that much of that damage in weightlessness is transient, recovering upon return to Earth.

This research once again highlights the imperative need to study the impact on various levels of artificial gravity on the human body. Will producing a 10% g environment — using centrifugal force — mitigate these negative impacts? Or will we have to simulate a full 1 g environment? Or something in between?

The first option is much easier in terms of engineering. The last will be complex and take time to develop.

At the moment almost no research has been done in this area. And it needs to happen soon, if people intend to go to Mars in the near future. Such journeys, six months minimum in weightlessness, are likely to leave the passengers somewhat debilitated upon arrival, no matter how much they exercise along the way. And being debilitated is not a good condition for a pioneer trying to build a new civilization on an alien world.

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NASA and Northrop Grumman work out rendezvous plan to get Cygnus to ISS

UPDATE: The plan worked and Cygnus is safely berthed at ISS.

According to a press release tonight, NASA and Northrop Grumman have figured out a new rendezvous plan to get Cygnus to ISS after its previous engine burns yesterday cut off prematurely and left it in the wrong orbit.

NASA and Northrop Grumman are targeting the safe arrival of the company’s Cygnus XL at approximately 7:18 a.m. EDT Thursday, Sept. 18, to the International Space Station. The Cygnus XL now will conduct a series of burns to bring the spacecraft to the space station for its robotic capture and installation.

NASA astronaut Jonny Kim is scheduled to capture Cygnus XL using the station’s Canadarm2 robotic arm with backup support from NASA astronaut Zena Cardman. After capture, the spacecraft will be installed on the Unity module’s Earth-facing port and will remain at the space station until March 2026.

The release also added this detail about why that engine burn ended too soon:

Data shared by the spacecraft confirmed that Cygnus XL operated as intended during two planned maneuvers when an early warning system initiated a shutdown command and ended the main engine burn because of a conservative safeguard in the software settings.

Apparently this cause has reassured them that the engine is in good shape for the final rendezvous burns.

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Premature engine cutoff forces postponement of Cygnus berthing to ISS

During the second of two engine burns today, designed to raise the orbit of Northrop Grumman’s Cygnus freighter to match ISS’s, the burn ended prematurely, placing the capsule in the wrong orbit.

Early Tuesday morning, Cygnus XL’s main engine stopped earlier than planned during two burns designed to raise the orbit of the spacecraft for rendezvous with the space station, where it will deliver 11,000 pounds of scientific investigations and cargo to the orbiting laboratory for NASA. All other Cygnus XL systems are performing normally.

The berthing, using one of the robot arms on ISS, had been planned for early tomorrow, Wednesday, but will not occur until both NASA and Northrop Grumman engineers have analyzed the issues and come up with “an alternate burn plan”.

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Progress docks safely with Zvezda module at ISS

ISS as of today
ISS as of today. Click for original.

In what is increasingly a worrisome procedure, Russia’s just launched Progress freighter successfully docked with the aft port of the Zvezda module at ISS this past weekend, bringing with it more than 5,000 pounds of supplies and research equipment.

The image to the right, annotated additionally by me, shows the present configuration of spacecraft at ISS. The concerns center on the stress fractures that have been found in the Zvezda hull, fractures that have caused the air leak on ISS and are believed attributable to the many dockings to the module since its launch in the late ’90s, as well as the module’s age. It was first built in the late ’80s, making it almost four decades old.

For recent dockings, NASA now closes the hatch between the Russian and American halves of the stations, just in case Zvezda experiences a catastrophic failure. The Russians seem less concerned, but nonetheless they also take extra care during dockings. It is my understanding their astronauts prepare their Soyuz capsule as a lifeboat and immediately escape during these operations.

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SpaceX launches Northrop Grumman’s Cygnus freighter to ISS

SpaceX today successfully launched Northrop Grumman’s Cygnus freighter with more than five tons of cargo, its Falcon 9 rocket lifting off from Cape Canaveral in Florida.

The first stage completed its fourth flight, landing back at Cape Canaveral. The two fairing halves completed their 3rd and 6th flights respectively. Cygnus is expected to be berthed to ISS using the robot arm on September 24, 2025. This is also the first flight of the stretched version of Cygnus, capable of carrying more cargo.

The leaders in the 2025 launch race:

118 SpaceX
53 China
13 Russia
12 Rocket Lab

SpaceX now leads the rest of the world in successful launches, 118 to 92. China also had its own launch scheduled for this evening, but no information about it has yet been released.

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Russia launches Progress to ISS

Russia today successfully launched a Progress freighter to ISS, its Soyuz-2 rocket lifting off from the Baikonur spaceport in Kazakhstan.

The freighter will dock with the aft port of the Zvezda module in two days. When it does so, expect NASA to require its astronauts to close the hatch between the American and Russia parts of ISS. The agency has real concerns about the stress fractures in Zvezda’s hull that are the cause of the station’s air leaks, and fears it could at some point fail catastrophically during a docking. The odds of this happening are small, but they are larger than they should be.

The leaders in the 2025 launch race:

115 SpaceX
53 China
12 Rocket Lab
12 Russia

SpaceX still leads the rest of the world in successful launches, 115 to 91. The company has another launch scheduled for later today.

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Cargo Dragon completes test burn to raise ISS’s orbit

The cargo Dragon that docked with ISS in late August successfully completed yesterday an engine burn lasting more than five minutes to see if it could raise ISS’s orbit.

On Wednesday, Sept. 3, SpaceX’s Dragon completed an initial burn to test the spacecraft’s new capability to help maintain the altitude of the International Space Station. Two Draco engines located in the trunk of Dragon, which contains an independent propellant system, were used to adjust the space station’s orbit through a maneuver lasting five minutes, three seconds. The initial test burn increased the station’s altitude by around one mile at perigee, or low point of station’s orbit, leaving the station in an orbit of 260.9 x 256.3 miles. The new boost kit in Dragon will help sustain the orbiting lab’s altitude through a series of longer burns planned periodically throughout the fall of 2025.

The Dragon will remain docked with ISS until December. It is expected it will do additional test burns during that time.

NASA wishes to get this capability from its own spacecraft so as to no longer have to rely entirely on the Russians, who have traditionally done these orbital adjustments using its Progress cargo freighters. SpaceX likely also wants to do these tests as an adjunct to its contract to build the de-orbit vehicle that will bring ISS down, after it is retired.

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Texas brewery tries brewing beer and growing barley on ISS

A Texas brewery dubbed Starbase Brewing (no connection to SpaceX) has just completed an experiment on ISS where it tried to brew beer in weightlessness as well as grow barley in simulated Martian soil.

Starbase Brewing — unrelated to Elon Musk’s space company or its South Texas city of Starbase — sent its MicroBrew-1 and OASIS experiments to the International Space Station aboard a SpaceX mission Aug. 1. They came back aboard a SpaceX Dragon spacecraft that splashed down eight days later off the coast of California.

…OASIS, short for “Optimizing Agriculture in Simulated Interplanetary Soils,” is the result of a partnership between the beer maker, Texas A&M AgriLife and Jaguar Space, a Colorado bioastronautics firm. According to Argroves, who launched the company in 2020, the goal was to grow barley in a mixture of Martian soil simulant with a byproduct of beermaking called Brewer’s Spent Grain and microbes.

The MicroBrew-1 experiment attempted to ferment beer, mixing “eight containers loaded with half wort — the sugary liquid extracted from malted grains — and half yeast.”

The company is far from manufacturing space-grown beer, but its founder seems focused on being the first brewery selling beer on Mars.

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Endurance capsule splashes down safely, returning four astronauts from ISS

SpaceX’s Endurance Dragon capsule successfully splashed down off the coast of California this morning, returning four astronauts from ISS after a five month mission.

I have embedded the live stream below. As of posting the capsule was about to be lifted from the water and placed in its nest on the recovery ship.

Once again it is important to note that this recovery is being done entirely by a private company and its employees. Once Endurance undocked from ISS NASA had no part to play. It purchased the ride from SpaceX, and SpaceX is providing the service.
» Read more

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Russia desperately lobbies the U.S. to continue and expand its space partnership

Roscosmos: a paper tiger
Roscosmos: a paper tiger

A string of short articles in Russia’s state-run press today, describing the meetings between the head of Roscosmos, Dmitry Bakanov, and interim NASA administrator Sean Duffy, suggest strongly that Russia is desperate to link itself with someone in order to continue its generally bankrupt space program.

Bakanov is making his first visit to the U.S. He and Duffy are also conducting the first face-to-face talks by the heads of their respective agencies in eight years. While the U.S. press has been entirely uninterested in these discussions, mostly because it knows little of substance will come of them other than an agreement to maintain the partnership at ISS through its planned retirement in 2030, the reaction by Russia’s press has been remarkably fawning, repeatedly proposing the U.S. and Russia expand their partnership beyond ISS:

Very clearly, Bakanov was trying to convince Duffy to consider a greater partnership, whereby Roscosmos and NASA do other space projects together. He might have even been offering to join NASA’s Artemis program to explore the Moon.

It appears from the other Russian state-run reports, however, that Duffy’s response was diplomatic but unenthused by such a proposal. All he apparently agreed to was to continue the ISS partnership, until the station’s retirement.
» Read more

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Endeavour launched successfully, carrying four astronauts to ISS

SpaceX’s Endeavour Dragon capsule has been successfully placed in orbit carrying four astronauts to ISS, its Falcon 9 rocket lifting off from Kennedy in Florida.

This is Endeavour’s sixth flight. It will dock at ISS in the early hours tomorrow. The first stage completed third flight, landing back in Florida.

The leaders in the 2025 launch race:

96 SpaceX
41 China
10 Rocket Lab
9 Russia

SpaceX now leads the rest of the world in successful launches, 96 to 71.

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