NASA wants more 'space tug' ideas to deorbit the International Space Station in a fiery finale

News
By
published

A spaceship will safely bring down the U.S. segment of the ISS after the program concludes in 2030.

a space station floats above earth, over an ocean or sea
International Space Station in low Earth orbit. (Image credit: NASA)

NASA is asking U.S. industry for proposals to create a "space tug" for removing the International Space Station from orbit in the early 2030s.

The agency plans to use a U.S. Deorbit Vehicle (USDV) to safely steer the International Space Station (ISS) into Earth's atmosphere. (White House officials previously called this vehicle a "space tug.") If all goes according to NASA's plan, after the ISS program concludes, flights and commercial research will  proceed on industry-led space stations, which are now in their early stages of development.

USDV proposals are due on Nov. 17, and more details about the requirements are available on this U.S. government website. NASA is allowing vendors to suggest much of the design of the vehicle as well as the best payment type: firm fixed price, or cost plus incentive fee for each of the initial phases (design, development, test and evaluation) to be followed by firm fixed price.

Related: NASA wants new 'deorbit tug' to bring space station down in 2030

"At the conclusion of the International Space Station program, the station will be deorbited in a controlled manner to avoid populated areas," NASA officials wrote in a blog post Sept. 20 announcing the request for proposals. A Russian Progress cargo vehicle, which is usually used to boost the ISS' orbit periodically, they added, would not be sufficient for the job. As such, "a new spacecraft solution would provide more robust capabilities for responsible deorbit."

NASA emphasized that the USDV would be responsible for deorbiting the U.S. segment, but did not provide details on how the other main international partners would remove their sections from orbit. "Partner contributions (are) based on mass percent ownership by agency," NASA officials said, framing the ISS deorbit as "a shared responsibility" among the partnership.

The USDV, they added, "will be a new spacecraft design or modification to an existing spacecraft that must function on its first flight, and have sufficient redundancy and anomaly recovery capability to continue the critical deorbit burn. As with any development effort of this size, the USDV will take years to develop, test and certify."

RELATED STORIES:

— NASA, private companies count on market demand for future space stations after ISS

— NASA working to get private space stations up and running before ISS retires in 2030

— The International Space Station will eventually die by fire

The other main partners on the ISS (listed in order of size of contribution, starting with the largest) include the Russian federal space agency Roscosmos, the European Space Agency, the Japan Aerospace Exploration Agency and the Canadian Space Agency (CSA). With the exception of the CSA, these partners all have at least one module on station. The CSA has robotics, namely Canadarm2, the Dextre handyman robot and supporting infrastructure.

With the exception of Roscosmos, the other partners have agreed to remain on station with NASA until 2030. Russia will withdraw no earlier than 2028 to pursue its own space exploration plans. Space partnerships with Russia were mostly severed after its internationally condemned invasion of Ukraine in February 2022, which is ongoing. But ISS relations remain normal in the meantime, NASA has emphasized.

Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: community@space.com.

Elizabeth Howell
Elizabeth Howell
Staff Writer, Spaceflight

Elizabeth Howell (she/her), Ph.D., is a staff writer in the spaceflight channel since 2022 specializing in Canadian space news. She was contributing writer for Space.com for 10 years before joining full-time. Elizabeth's reporting includes multiple exclusives with the White House, speaking several times with the International Space Station, witnessing five human spaceflight launches on two continents, flying parabolic, working inside a spacesuit, and participating in a simulated Mars mission. Her latest book, "Why Am I Taller?" (ECW Press, 2022) is co-written with astronaut Dave Williams. 

18 Comments Comment from the forums
  • fj.torres
    Instead of deorbiting it, why not fill it with noble gas, *raise* the orbit, and leave it at high altitude as a monument/future museum, like the WWII ship museums?
    Attach a bunch of ion thrusters and let its own solar cells boost it? Might even be cheaper than building a vehicle just to destroy it.
    Reply
  • steve_foston
    If the ISS is going to be deorbited then place it on the surface of the moon - I agree with FJ it should be turned into a museum as it is the largest man made object ever created and as such it is an important historical artefact. Imagine the pyramids being destroyed! As the space tourism industry grows it would then become an important destination. Much better than the vandalism involved in polluting the oceans.
    Reply
  • fj.torres
    steve_foston said:
    If the ISS is going to be deorbited then place it on the surface of the moon - I agree with FJ it should be turned into a museum as it is the largest man made object ever created and as such it is an important historical artefact. Imagine the pyramids being destroyed! As the space tourism industry grows it would then become an important destination. Much better than the vandalism involved in polluting the oceans.
    Maybe time to start a petition?
    Remind the idiotpoliticians who they work for (when not lining their pocket with bribes). Preserve the station!
    Reply
  • benglover2015
    fj.torres said:
    Instead of deorbiting it, why not fill it with noble gas, *raise* the orbit, and leave it at high altitude as a monument/future museum, like the WWII ship museums?
    Attach a bunch of ion thrusters and let its own solar cells boost it? Might even be cheaper than building a vehicle just to destroy it.
    Hmm, good question. Someone asked that here, too. <https://www.quora.com/Why-cant-we-send-the-International-Space-Station-into-deep-space-instead-of-burning-it-up-in-the-atmosphere>

    In short, "The cost to develop the technology to accomplish the move and the cost of executing the move would be great. It is not realistic to expect Congress to pay for such a thing. And if they did, it would likely be in lieu of going to Mars or returning to the Moon or whatever the next great adventure will be. Preserving the past would prevent the future." - Robert Frost
    Reply
  • fj.torres
    benglover2015 said:
    Hmm, good question. Someone asked that here, too. <https://www.quora.com/Why-cant-we-send-the-International-Space-Station-into-deep-space-instead-of-burning-it-up-in-the-atmosphere>

    In short, "The cost to develop the technology to accomplish the move and the cost of executing the move would be great. It is not realistic to expect Congress to pay for such a thing. And if they did, it would likely be in lieu of going to Mars or returning to the Moon or whatever the next great adventure will be. Preserving the past would prevent the future." - Robert Frost
    Riiightt...

    That's the same excuse they used to let SKYLSB burn inhstead of adding the other two, including the one fully finished and sitting in the SMITHSONIAN. And thrn spent 20 years to assemble the potluck station at ten times the cost.

    Have they actually priced it?
    What's the price for an RFQ?
    Ion thrusters are not new tech and the station cused an be moved as is.
    And there's several New Space companies developing new ones on their own.

    Obviously the price will be outrageous if they sign with the old space friends of the party but there are plenty of cheaper options.

    The whole point of ion thrusters is they work for long periods of time so the could be mounted on a CYGNUS full of fuel and draw power from the station solar wings.
    Not talking a moon landing or GEO but elevating the orbit regularly to keep it up above the junk belt.

    Wanna bet if they give it away to a New Space consortium they find a way to refurbish anf maintain it and use it as a commercial station *and* make a profit?

    Eventually the price of moving it to GEO will drop.
    Reply
  • billslugg
    ISS is nearing the end of its certified lifetime. The metal beams and metal skin may develop tiny cracks and fail suddenly. When the thousands of suppliers provided NASA with the parts, they all gave projected lifetimes NASA agreed to. Those times are going to run out some day. No one wants to be the scapegoat if an astronaut dies on an uncertified vehicle. Once the craft is retired, no one will go near it. No amount of refurbishment in orbit would be sufficient.
    ISS cannot exist unless someone is living in it. There are ongoing maintenance tasks needed simply to maintain its orientation.
    The ISS cannot exist without being able to look up at other satellites in order to fix its position, thus cannot exist at GEO, it would wander.
    People cannot go outside the Van Allen belts but for very short times or with heavy shielding. No one could occupy it in GEO.
    There is no scientific value in saving it. NASA has zero interest in saving it.

    It is unlikely to be saved.
    Reply
  • Unclear Engineer
    Getting back to discussing the job of deorbiting it, that doesn't sound very difficult. They have been using Progress rockets to boost its orbit all along, and are (were , did ?) working on having SpaceX provide a boost capability, too. Deorbiting is mainly boosting in the opposite direction. I guess they need to be careful that the thrust is not too great for the structural integrity, but strong enough that the orbit can be changed sufficiently to make the reentry point predictable to the necessary precision to put the stuff that survives reentry into the South Pacific "graveyard". Is there really anything more to it? I would think we already have engines and fuel tanks and guidance infrastructure available.
    Reply
  • billslugg
    This paper says the Russian cargo ships leaving ISS use a 100 m/s delta V in order to land at a predictable spot.
    ISS mass is 419,000 kg
    It is moving at 7,900 m/s
    Kinetic energy on orbit is 1/2 x m x v^2 = 1.308e13 joules.
    Velocity after retro burn = 7,900-100 = 7,800 m/s
    Kinetic energyafter retro burn = 1.274e13 joules
    Delta energy required = 6e11 joules = 6e8 BTU = 27,000 pounds of rocket fuel

    That is a fairly large tug.

    https://conference.sdo.esoc.esa.int/proceedings/sdc7/paper/1008/SDC7-paper1008.pdf#:~:text=In%20a%20targeted%20decay%2C%20the%20energy%20change%20to,less%20than%201%25%20of%20the%20total%20orbital%20energy.
    Reply
  • Classical Motion
    No one likes my ionizing laser for net charge on debris idea. Before that thing comes down, why not install coils and generate a M field and try some magnetic steering? I have read just a length of wire can generate large voltages and currents out there. Let's test Ampere principles on a large scale.
    Reply
  • billslugg
    If you generate a current with solar cells and then run a current through a loop you can accelerate ISS. It would take a lot of power.
    Reply