Back on Thursday, I posted an article about the House NASA Reauthorization bill that was going through the process and the impacts coming, including putting up more programs for the private sector to bid on and take the lead in them.
When that bill passed, lawmakers had added an additional change to it.
Another add-on to the authorization bill would require NASA to reassess whether to guide the International Space Station (ISS) toward a destructive atmospheric reentry after it is decommissioned in 2030. The space agency’s current plan is to deorbit the space station in 2031 over the Pacific Ocean, where debris that survives the scorching reentry will fall into a remote, unpopulated part of the sea.
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The amendment tacked onto this year’s bill would not change the timeline for ending operations on the ISS, but it asks NASA to reconsider its decision about what to do with the complex after retirement.
The amendment would direct NASA to “carry out an engineering analysis to evaluate the technical, operational, and logistical viability of transferring the ISS to a safe orbital harbor and storing the ISS in such harbor after the end of the operational low-Earth orbit lifetime of the ISS to preserve the ISS for potential reuse and satisfy the objectives of NASA.”
Rep. George Whitesides (D-Calif.) and cosponsor Rep. Nick Begich (R-Alaska) submitted the amendment, much like the amendment mentioned in Thursday's post had bipartisan sponsors. It probably "looks better" (sells better) than an amendment put up by only one side. Whitesides was a NASA chief of staff and had been an executive in the space industry before his election to the House.
In essence this is the same concept that several people have asked about retiring the ISS here on the blog and, honestly, gets asked everywhere. Instead of splashing the ISS into a deep spot in the Pacific, why not put it into a higher orbit?
“The International Space Station is one of the most complex engineering achievements in human history,” Whitesides said. “It represents more than three decades of international collaboration and investment by US taxpayers estimated at well over $100 billion. Current plans call for the station to be deorbited at the end of its service life in 2030. This amendment does not seek to change that policy. Instead, it asks a straightforward question: Before we permanently dispose of an asset of this magnitude, should we fully understand whether it’s viable to preserve it in orbit for potential use by future generations?”
Of course, this has been analyzed before in the sense of determining just how much orbital velocity has to be changed to get the desired change. That was required to create the contract telling the eventual winning bidder (SpaceX) how much change in orbital velocity is required to start to deorbit the ISS. A good approximation of everything in the Low Earth Orbit range of the station is that its orbital velocity is 17,000 mph. The required change in velocity is 127 mph, which is a tiny percentage of its current velocity: 0.75%.
Changing its speed by just 127 mph will consume about 10 tons (9 metric tons) of propellant, according to a NASA analysis released in 2024.
Everyone now is thinking how much mass are we talking about? The station mass is around 450 tons, equivalent to two freight train locomotives, and measures about the size of a football field.
The analysis document shows that NASA considered alternatives to discarding the space station through reentry. One option NASA studied involved moving the station into a higher orbit. At its current altitude, roughly 260 miles (420 kilometers) above the Earth, the ISS would take one to two years to reenter the atmosphere due to aerodynamic drag if reboosts weren’t performed. NASA does not want the space station to make an uncontrolled reentry because of the risk of fatalities, injuries, and property damage from debris reaching the ground.
The amount of fuel required is around twice that 10 tons necessary to de-orbit the ISS.
At that altitude, without any additional boosts, NASA says the space station would likely remain in orbit for 100 years before succumbing to atmospheric drag and burning up. Going higher still, the space station could be placed in a 1,200-mile-high (2,000-kilometer) orbit, stable for more than 10,000 years, with about 146 tons (133 metric tons) of propellant.
There are two problems with sending the ISS to higher altitudes. One is that it would require the development of new propulsive and tanker vehicles that do not currently exist, according to NASA.
Developing new tankers and a new "Deorbit Dragon" isn't the end to the possible difficulties. Putting the station in a higher orbit, also exposes it to a higher chance of impact from space junk. The engineers who did that 2024 analysis say the peak risk is at an orbital height of 500 miles. “This means that the likelihood of an impact leaving station unable to maneuver or react to future threats, or even a significant impact resulting in complete fragmentation, is unacceptably high.”
An alternative they don't spend much time examining is "leave it where it is." NASA said in 2024 that engineers have “high confidence” that the primary structure of the station could support operations beyond 2030. It's undoubtedly higher risk the longer the station stays there, and maybe some sections could be replaced or just left empty and unused.
The oldest segments of the station have been in orbit since 1998, undergoing day-night thermal cycles every 45 minutes as they orbit the planet. The structural stability of the Russian section of the outpost is also in question. Russian engineers traced a small but persistent air leak to microscopic structural cracks in one Russian module, but cosmonauts were able to seal the cracks, and air pressure in the area is “holding steady,” a NASA spokesperson said last month.
All that said, there's absolutely nothing wrong with asking, "are we doing the right thing or being stupid?" Paying for another round of analysis, perhaps with some different assumptions, could be good thing.
Then there's the way NASA has been encouraging the development of private space stations like the Vast Haven-1. Let the private sector develop the stations, make income from them, and let them decide how to handle problems like this. They're not as far along as everyone was talking about, but when has a new technology not had moments like that?
I'll just conclude with a saying that I like. "When you're doing things no one has ever done before, you learn things no one has ever known before." A decision like this has several of those things no one has done before embedded in it.
Artist’s illustration of SpaceX’s deorbit vehicle, based on the design of the company’s Dragon spacecraft. The modified spacecraft will have 46 Draco thrusters—30 for the deorbit maneuvers and 16 for attitude control. Credit: SpaceX
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