Perhaps the hardest part of sending people into space is actually getting to space in the first place.
Any rocket capable of escaping Earth’s atmosphere must burn off most of its fuel within the first few minutes of launch, severely limiting what it can do or where it can go once in space.
“The goal is to deliver thrusters from the surface of the Moon.”
One company aiming to circumvent this limitation is ETA Space. He builds what is effectively a gas station in low Earth orbit, so that instead of falling back to Earth or just taking up space while the tank is empty, rockets and satellites can live longer and travel further.
“It allows the payload customer to buy a smaller rocket to send out and then refuel. So instead of spending $150 million on a rocket, you could spend $20 million on a smaller one. said Bill Notardonato, CEO and Founder of ETA Space. Reverse.
He thinks ETA’s gas station concept, which he calls “CryoDock”, could allow more players to send missions to places humans haven’t yet reached – including Mars – by making the whole effort easier and cheaper. Eventually, ETA wants to set up a station at strategic points in space, such as the Moon.
“Eventually the goal is to deliver propellants from the surface of the Moon, you’ll get hydrogen and oxygen from the water there. low Earth orbit,” says Notardonato.
ETA Space gas stations will likely service organizations with large satellites and expensive spacecraft designed to travel long distances in space, he adds.
“Let’s say they launch a mission to Jupiter. You can launch and enter orbital insertion, then [the fuel tank will] be mostly empty. This is where ETA Space’s LOXSAT, or cryogenic fuel station, would theoretically enter to replenish fuel and send the spacecraft on its way.
“You will get hydrogen and oxygen from the water there.”
Sending a rocket with less fuel means there can be less rocket too – lower fuel volumes require less thrust and, in turn, smaller launch vehicles to get to space.
“You could surpass [the tank up] and refuel to get the energy needed to do Earth’s starting burn. So suddenly now science missions can be launched on smaller launch vehicles and send larger masses, both to the inner and outer solar system.
Getting the fuel into space will require a very large launch in the first place – until ETA can settle on the Moon of course. Notardonato says scale can work to the company’s advantage, however — ultimately other partners will save on their launch costs.
“Let’s say we launch 15 tons of propellant, but each customer only needs 500 kg. We can do 30 different services and so we get economies of scale that way.
Enter, LOXSAT 1
The first step in expanding its in-orbit refueling business will take the form of LOXSAT 1, a small demonstration satellite that will test two of ETA Space’s core technologies. The test has already been paid for by NASA. Costing $27 million, ETA Space and the agency plan to start building LOXSAT 1 in January 2023. A launch window could be as early as March 2024.
LOXSAT 1 is designed to prove that cryogens like liquid oxygen (“LOX”) can be stored for long periods of time in space. Although the fuel has been used for a number of rockets, including in the first stage of SpaceX’s Falcon 9, it was not considered “storable” until now. In turn, deeper space missions have tended to use “hypergolic” fuels that burn on contact, such as monomethylhydrazine and nitrogen tetroxide. So if humans want to go further into space, we will have to find an alternative to these dangerous fuels.
“They are very toxic, very dangerous and difficult to handle on the ground. Not at all environmentally friendly and they are not easy to manufacture. If you go to the Moon or Mars, you won’t be making your own nitrogen tetroxide for a while,” says Notardonato. LOX might provide an alternative – if it can be stored.
“We are not used to storing large amounts of cryogens in space for long periods of time because they evaporate,” says Notardonato.
“Hydrogen in particular boils at 20 degrees above absolute zero. So in space, any solar radiation that hits it and any Earth radiation that hits it is going to directly heat the boiling liquid, and so you tend to lose your propellant.
“Long-term storage without evaporation is one of the key technologies that we will prove. We have done it in the field many times. Now we just have to prove it in microgravity. he adds.
“SpaceX will be the Mac and we will be the PC.”
The LOXSAT mission will also help prove another critical aspect of CryoDock: whether fuel can be pumped from one spacecraft to another in space.
“The first tank is cold, but the second tank is hot, and the transfer line is usually hot,” says Notardonato. “As [the fuel] cools in the other system, it boils and creates more steam. You must therefore evacuate this vapor.
So far, no one has succeeded in demonstrating fuel transfer in space.
“It takes so much energy and so much cost to lift one kilogram of mass into orbit. If you lose, [say]20% of that during transfer due to cooling is just very uneconomical. [But] we have methods that we have developed that can perform lossless cooling and no loss transfer from tank to tank,” says Notardonato.
There are, however, big “what ifs” that need to be answered – something Notardonato acknowledges.
“What we’re not as confident about is the behavior of fluids in microgravity,” says Notardonato, who explains that there are “liquid acquisition” devices inside fuel tanks that, under Earth’s gravity, use surface tension to direct fuel out of the tank. . But it’s unclear whether they will behave the same way in space.
The company places a camera inside the liquid oxygen tank to see for itself.
“A few people have flown cameras into space to observe cryogenic liquids, but they’ve usually been on stage one and stage two. [of a launch rocket]. So you get 10 to 15 minutes, maybe half an hour of data in microgravity,” he says.
“We’re going to have nine months of microgravity data and we’re going to be able to vary thrust levels, spin rates, things like that. So we can accurately anchor all those zero-G patterns that NASA and other researchers have been working on for years.
The long way to a cosmic gas pump
ETA Space is not the only company working on the issue of propellant storage in space. In fact, if humans are to establish a permanent presence on the Moon, SpaceX will need to find a way to refuel its Starship-based human landing system. But fundamentally, Notardonato thinks ETA is doing something different.
“We pack as many tech demos as possible into a small mission over a long period of time and try to make it more agnostic,” says Notardonato.
“With SpaceX, their development money goes only to their mission architecture. And United Launch Alliance directs theirs to the higher stage of their architecture only. We want to create a propellant repository called Cryodock that is commercially available for anyone using our standardized umbilical disconnections.”
“SpaceX will be the Mac and we will be the PC,” he says.
ETA space: the chronology
So when will LOXSAT 1 take off? There is a long way to go, says Notardonato.
“On June 15, we have to have our critical design review with NASA. At this point, our design is about 95% complete,” says Notardonato.
“We have issued most major procurements for electronics, heaters, structures, tanks and valves.”
“It will take about three months to manufacture in the workshop.”
Then you have to wait six months for parts and test subsystems as they come in.
“We’ll start putting it all together in January next year,” he says.
“It will take about three months to manufacture in the workshop. And then we’ll have about four months to test our payload here before shipping it to Rocket Lab. Rocket Lab will take it and pair it with their vehicle, and then we’ll do six months of built-in testing on it.
- June 15, 2022: NASA reviews ETA Space’s design for LOXSAT 1.
- December 2022 – January 2023: ETA Space obtains the parts it needs and begins the first tests.
- January 2023: Start of construction of LOXSAT 1.
- March 2023: The first possible window for LOXSAT 1 must be completed.
- July 2023: Potential window to ship LOXSAT 1 to Rocket Lab – the company launching the satellite.
- Winter-Spring 2024: Rocket Lab completes the attachment of LOXSAT 1 to the launcher and the tests.
- March 2024: earliest possible launch window for LOXSAT 1.
On the horizon…
The hope is that LOXSAT 1 will launch on a Rocket Lab Electron rocket in March 2024 from a launch site in New Zealand. If successful, then it will be up to LOXSAT 2 to turn what its predecessor proved into a viable commercial venture.
It will (literally) be a much bigger deal, Notardonato says.
“There’s a lot going on with LOXSAT 2 that I can’t talk about,” he says, but he hints that it will be a bigger payload than LOXSAT 1.
“But if we launch a Rocket Lab vehicle, it will have to be something larger than the Electron.”
HORIZONS is a newsletter about today’s innovations that will shape the world of tomorrow. This is an adapted version of the May 26 edition. Predict the future by free registration.