Author Topic: Building a Spacecraft to Deorbit ISS 'Not Optional'.  (Read 5441 times)

Offline jstrotha0975

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NASA’s Aerospace Safety Advisory Panel (ASAP) urged the space agency to develop a space tug to deorbit the ISS, saying that the deorbit vehicle is “not optional,”

In this thread we try to figure out a solution.

Source: https://www.msn.com/en-us/news/technology/building-a-spacecraft-to-deorbit-iss-not-optional-claims-nasa-safety-panel/ar-AA1iXJVK

Offline jstrotha0975

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Re: Building a Spacecraft to Deorbit ISS 'Not Optional'.
« Reply #1 on: 10/27/2023 08:06 pm »
I would like to start off. I'm not an aerospace expert but I would like to try. Take an old Dragon 1 capsule and modify it into a space tug. Since it won't be coming back, it doesn't need a heat shield. I think this is the cheapest and easiest solution.

Offline Jim

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Re: Building a Spacecraft to Deorbit ISS 'Not Optional'.
« Reply #2 on: 10/27/2023 08:11 pm »
I would like to start off. I'm not an aerospace expert but I would like to try. Take an old Dragon 1 capsule and modify it into a space tug. Since it won't be coming back, it doesn't need a heat shield. I think this is the cheapest and easiest solution.

Not big enough and thrusters point the wrong way

Offline Jim

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Re: Building a Spacecraft to Deorbit ISS 'Not Optional'.
« Reply #3 on: 10/27/2023 08:12 pm »

In this thread we try to figure out a solution.


A larger Cygnus SM is the solution.

Offline Coastal Ron

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Re: Building a Spacecraft to Deorbit ISS 'Not Optional'.
« Reply #4 on: 10/27/2023 08:21 pm »
I would like to start off. I'm not an aerospace expert but I would like to try. Take an old Dragon 1 capsule and modify it into a space tug. Since it won't be coming back, it doesn't need a heat shield. I think this is the cheapest and easiest solution.

Not big enough and thrusters point the wrong way

Yeah, you'd need to put an engine and propellant tank in the trunk area. Which I'm sure could be done if you extended the length of the trunk, but not sure if this is the right approach.


In this thread we try to figure out a solution.


A larger Cygnus SM is the solution.

I like Cygnus as a tug concept in its current size, so this solution seems to make sense - NASA pays for the up-sized service module, and Northrop Grumman gets a new product to offer to the market - Win-Win!  :D
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline jstrotha0975

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Re: Building a Spacecraft to Deorbit ISS 'Not Optional'.
« Reply #5 on: 10/27/2023 08:26 pm »
I forgot to mention in my previous posts that the solution needs to be as cheap as possible due to possible budget cuts according to the source article I posted.
« Last Edit: 10/27/2023 08:26 pm by jstrotha0975 »

Online DanClemmensen

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Re: Building a Spacecraft to Deorbit ISS 'Not Optional'.
« Reply #6 on: 10/27/2023 08:29 pm »
A larger Cygnus SM is the solution.
To minimize development time and expense, is it possible to use multiple Cygnuses (Cygni?)  serially?

Online Yellowstone10

I would like to start off. I'm not an aerospace expert but I would like to try. Take an old Dragon 1 capsule and modify it into a space tug. Since it won't be coming back, it doesn't need a heat shield. I think this is the cheapest and easiest solution.

Not big enough and thrusters point the wrong way

I'm curious what the back-of-the-envelope numbers suggest would happen if you attached a Crew Dragon to IDA-2 and then burned the SuperDracos to depletion. Probably not enough propellant, but how much are we off by?

Offline Sam Ho

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Re: Building a Spacecraft to Deorbit ISS 'Not Optional'.
« Reply #8 on: 10/27/2023 09:19 pm »
I would like to start off. I'm not an aerospace expert but I would like to try. Take an old Dragon 1 capsule and modify it into a space tug. Since it won't be coming back, it doesn't need a heat shield. I think this is the cheapest and easiest solution.

Not big enough and thrusters point the wrong way

I'm curious what the back-of-the-envelope numbers suggest would happen if you attached a Crew Dragon to IDA-2 and then burned the SuperDracos to depletion. Probably not enough propellant, but how much are we off by?

SuperDraco has far too much thrust.  There is an existing thread discussing the Deorbit RFI.  The Deorbit Module needs to provide 3-6kN of thrust (maybe higher if it can ramp up slowly).

twitter.com/jeff_foust/status/1560739973833412608

Quote
NASA issued an RFI today looking for industry input on a proposed deorbit module for the ISS to bring it down at the end of its life, something originally projected to be done by Progress cargo spacecraft. https://sam.gov/opp/74252cfe7d49416abae0977fe4fd503c/view

https://twitter.com/jeff_foust/status/1560740299680497667

Quote
From a NASA statement: ISS partners “developed a strategy and action plan that evaluated the use of multiple Roscosmos Progress spacecraft to support deorbit operations. These studies indicated additional spacecraft may provide more robust capabilities for deorbit.”

Offline AmigaClone

A larger Cygnus SM is the solution.
To minimize development time and expense, is it possible to use multiple Cygnuses (Cygni?)  serially?

I agree that using the Cygnus SM as the basis for the design of the deorbit module might be the cheapest solution. In theory, it wouldn't need a full-sized cargo module, although keeping it might reduce the complexity of the project.

Quote
I'm curious what the back-of-the-envelope numbers suggest would happen if you attached a Crew Dragon to IDA-2 and then burned the SuperDracos to depletion. Probably not enough propellant, but how much are we off by?

One thing to remember is that according to current plans, the forward CBM of the Harmony module will be empty with the PMA-2/IDA-2 having been relocated when the first Axiom module arrives.

Online DanClemmensen

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Re: Building a Spacecraft to Deorbit ISS 'Not Optional'.
« Reply #10 on: 10/27/2023 09:46 pm »
A larger Cygnus SM is the solution.
To minimize development time and expense, is it possible to use multiple Cygnuses (Cygni?)  serially?
I agree that using the Cygnus SM as the basis for the design of the deorbit module might be the cheapest solution. In theory, it wouldn't need a full-sized cargo module, although keeping it might reduce the complexity of the project.
Even the most trivial modification would require a development project, and any depelopment project costs time and money. I was asking about just using multiple Cygnus units of the existing design. Zero development time. Zero development cost. After the last crew performs the berthing of the last Cygnus in this sequence, they turn off the lights and go home on their CCP spacecraft, and then that last Cygnus is fired up for the final deorbit burn.

Offline AS_501

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Re: Building a Spacecraft to Deorbit ISS 'Not Optional'.
« Reply #11 on: 10/27/2023 09:55 pm »
I assume the two large engines on the rear of Zvezda are not up to the task or long out of commission(?).
Launches attended:  Apollo 11, ASTP (@KSC, not Baikonur!), STS-41G, STS-125, EFT-1, Starlink G4-24, Artemis 1
Notable Spacecraft Observed:  Echo 1, Skylab/S-II, Salyuts 6&7, Mir Core/Complete, HST, ISS Zarya/Present, Columbia, Challenger, Discovery, Atlantis, Dragon Demo-2, Starlink G4-14 (8 hrs. post-launch), Tiangong

Online Yellowstone10

SuperDraco has far too much thrust.  There is an existing thread discussing the Deorbit RFI.  The Deorbit Module needs to provide 3-6kN of thrust (maybe higher if it can ramp up slowly).

Sure, but just in terms of the total amount of propellant needed to do the job, assuming a typical NTO/MMH thruster, how does that compare to "one Dragon's worth of fuel" as a reference point?

Offline Sam Ho

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Re: Building a Spacecraft to Deorbit ISS 'Not Optional'.
« Reply #13 on: 10/27/2023 10:40 pm »
SuperDraco has far too much thrust.  There is an existing thread discussing the Deorbit RFI.  The Deorbit Module needs to provide 3-6kN of thrust (maybe higher if it can ramp up slowly).

Sure, but just in terms of the total amount of propellant needed to do the job, assuming a typical NTO/MMH thruster, how does that compare to "one Dragon's worth of fuel" as a reference point?
Also from that same presentation, the delta-V requirement is 41-47m/s, plus 700-1700kg of attitude control propellant.  So, about 3 Dragons' worth of fuel.

Offline Jim

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Re: Building a Spacecraft to Deorbit ISS 'Not Optional'.
« Reply #14 on: 10/28/2023 12:13 pm »
I forgot to mention in my previous posts that the solution needs to be as cheap as possible due to possible budget cuts according to the source article I posted.

No, this is going to cost what it is going to cost.

Offline Jim

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Re: Building a Spacecraft to Deorbit ISS 'Not Optional'.
« Reply #15 on: 10/28/2023 12:14 pm »
A larger Cygnus SM is the solution.
To minimize development time and expense, is it possible to use multiple Cygnuses (Cygni?)  serially?
I agree that using the Cygnus SM as the basis for the design of the deorbit module might be the cheapest solution. In theory, it wouldn't need a full-sized cargo module, although keeping it might reduce the complexity of the project.
Even the most trivial modification would require a development project, and any depelopment project costs time and money. I was asking about just using multiple Cygnus units of the existing design. Zero development time. Zero development cost. After the last crew performs the berthing of the last Cygnus in this sequence, they turn off the lights and go home on their CCP spacecraft, and then that last Cygnus is fired up for the final deorbit burn.

Needs to be a single vehicle

Offline Jim

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Re: Building a Spacecraft to Deorbit ISS 'Not Optional'.
« Reply #16 on: 10/28/2023 12:15 pm »
It is going to need about 15 tons of biprop.

Offline Emmettvonbrown

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Re: Building a Spacecraft to Deorbit ISS 'Not Optional'.
« Reply #17 on: 10/28/2023 04:22 pm »
Desorbiting 400 metric tons is no picnic, even if it only takes 50 m/s or 100 m/s of braking... that's 400 mt.

I remember that Mir was desorbited by a Progress, but it was 1/4 the weight.

Online DanClemmensen

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Re: Building a Spacecraft to Deorbit ISS 'Not Optional'.
« Reply #18 on: 10/28/2023 04:47 pm »
A larger Cygnus SM is the solution.
To minimize development time and expense, is it possible to use multiple Cygnuses (Cygni?)  serially?
I agree that using the Cygnus SM as the basis for the design of the deorbit module might be the cheapest solution. In theory, it wouldn't need a full-sized cargo module, although keeping it might reduce the complexity of the project.
Even the most trivial modification would require a development project, and any depelopment project costs time and money. I was asking about just using multiple Cygnus units of the existing design. Zero development time. Zero development cost. After the last crew performs the berthing of the last Cygnus in this sequence, they turn off the lights and go home on their CCP spacecraft, and then that last Cygnus is fired up for the final deorbit burn.

Needs to be a single vehicle
I believe you, but I am too ignorant to know why this is true, so I would appreciate it if you would educate me. If the earlier small burns get it low enough, maybe that last Cygnus would not have enough energy to cause a precise enough de-orbit?

Offline Perchlorate

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Re: Building a Spacecraft to Deorbit ISS 'Not Optional'.
« Reply #19 on: 10/28/2023 05:16 pm »

In this thread we try to figure out a solution.


A larger Cygnus SM is the solution.

Inconceivable that one would use anything but a Cygnus for the ISS' "swan song."
Pete B, a Civil Engineer, in an age of incivility.

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