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Thread: Space tug

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    Space tug

    The Chinese were going to test an upper stage later this year, that they described as a space tug. I got a lot of flake with that description in the thread "space race".

    Then I read this in spaceflight101

    " A Soyuz 2-1B rocket blasted off from Site 31/6 at the Baikonur Cosmodrome on Tuesday at 15:58 UTC carrying the Meteor-M #2 satellite and six secondary payloads into orbit.

    Following a thundering blastoff from Baikonur, Soyuz successfully executed a nominal ascent mission taking nine and a half minutes to deliver the Fregat Upper Stage and the seven payloads into a Parking orbit."

    Not heard about the "Fregat" before, so I looked it up in Wikipedia.

    " Fregat (Russian: Фрегат, frigate) is a space tug developed by NPO Lavochkin in the 1990s. Its main engine is a liquid propellant rocket that uses UDMH and N2O4 as propellants."

    As the Chinese press were speculating this sort of crafts will also be used in space construction and ferrying stuff to other parts of space, a thread dedicated to this topic would be appropriate.
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    Quote Originally Posted by selvaarchi View Post
    The Chinese were going to test an upper stage later this year, that they described as a space tug. I got a lot of flake with that description in the thread "space race".
    I know I was the one that gave you most of that flack.
    (Or maybe you do mean flake. Did the stress give you lots of dandruff. )

    But; I was more concerned about the the name inferring things that it isn't rather than the name itself. It seems to have triggered you speculating about deep space tugs, orbit to orbit and such stuff.
    The name does bother me for that reason, but as long as it's kept in context of its use, I'm OK with it.

    Here's a more detailed description and history of the Fregat.
    While I still consider it more of an upper stage than a tug, it does seem very robust and probably more on par with the Apollo service module.
    A 3 year on-orbit lifespan is impressive, and the drop tanks sound interesting.

    Quote Originally Posted by selvaarchi View Post
    As the Chinese press were speculating this sort of crafts will also be used in space construction and ferrying stuff to other parts of space
    It definitely gets their feet wet, but the do have a bit to go. I think the working components that need to be added might be a bigger challange than the propulsion unit, but I'm not sure what kind of applications they have in mind.

    Quote Originally Posted by selvaarchi View Post
    a thread dedicated to this topic would be appropriate.
    Yes, thank you.

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    Quote Originally Posted by NEOWatcher View Post
    I know I was the one that gave you most of that flack.
    (Or maybe you do mean flake. Did the stress give you lots of dandruff. )

    But; I was more concerned about the the name inferring things that it isn't rather than the name itself. It seems to have triggered you speculating about deep space tugs, orbit to orbit and such stuff.
    The name does bother me for that reason, but as long as it's kept in context of its use, I'm OK with it.

    Here's a more detailed description and history of the Fregat.
    While I still consider it more of an upper stage than a tug, it does seem very robust and probably more on par with the Apollo service module.
    A 3 year on-orbit lifespan is impressive, and the drop tanks sound interesting.


    It definitely gets their feet wet, but the do have a bit to go. I think the working components that need to be added might be a bigger challange than the propulsion unit, but I'm not sure what kind of applications they have in mind.


    Yes, thank you.
    I ment flack. I still believe that we should have rockets to take us to LEO and bring us back. From there it should be refuelable tugs that can take it from there to any other location.

    As these tugs will never have to experience going through the atmosphere they do not have to be aerodynamically designed. Also we will at least get reusable crafts being used and should bring down cost.
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    Quote Originally Posted by selvaarchi View Post
    I ment flack. I still believe that we should have rockets to take us to LEO and bring us back. From there it should be refuelable tugs that can take it from there to any other location.
    Not if it's "just a tug".
    It only gets advantageous if there is extra bulk and weight associated with the operation of that tug, expensive equipment required to operate the tug that you wouldn't want to launch each time, or if the fuel is coming from somewhere else with a much lower delta-v.
    Something like a space habitat, or extensive construction equipment are examples.

    Most of these tugs are fuel (Fregat is 80%). By the time you have a transfer craft, possible loss from transfer of fuel, and fuel requirements for rendezvous, you probably end up with more cost in weight and fuel than just sending another one up.

    Quote Originally Posted by selvaarchi View Post
    As these tugs will never have to experience going through the atmosphere they do not have to be aerodynamically designed.
    Does Fregat look aerodynamic to you?

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    Quote Originally Posted by NEOWatcher View Post
    Not if it's "just a tug".
    It only gets advantageous if there is extra bulk and weight associated with the operation of that tug, expensive equipment required to operate the tug that you wouldn't want to launch each time, or if the fuel is coming from somewhere else with a much lower delta-v.
    Something like a space habitat, or extensive construction equipment are examples.

    Most of these tugs are fuel (Fregat is 80%). By the time you have a transfer craft, possible loss from transfer of fuel, and fuel requirements for rendezvous, you probably end up with more cost in weight and fuel than just sending another one up.


    Does Fregat look aerodynamic to you?
    The Chinese and Russian ones are either 3rd or 4th stages of a rocket so they at least have to be aerodynamically covered. They are both for one off use.

    I am looking for a multiple use tug that uses energy efficient engines for propulsion.
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    Quote Originally Posted by selvaarchi View Post
    The Chinese and Russian ones are either 3rd or 4th stages of a rocket so they at least have to be aerodynamically covered.
    Yes; but that doesn't affect their design other than mounting methods.
    Quote Originally Posted by selvaarchi View Post
    They are both for one off use.
    I think the Russian one has some potential for re-use because of it's on-orbit lifetime. But; for the reasons I stated above, it wouldn't be advantageous as it is now.

    Quote Originally Posted by selvaarchi View Post
    I am looking for a multiple use tug that uses energy efficient engines for propulsion.
    Yes; Ion propulsion might be a good goal at the moment. It fits a lot of the things I mentioned earlier.
    - The engines and power supply are the reusable parts and are complex and bulky leaving the fuel as a much lower ratio of the craft.
    - Propellent efficiency adds to this ratio.
    - (just a guess) I think any fuel transfer would lose less because it's not cryogenic or volatile.
    The only disadvantage would be it's overall acceleration.

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    Acceleration is not a must in most cases. For moving a setallite from LEO to GEO or moving parts for a space construction, precision is more important than speed.
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    Quote Originally Posted by selvaarchi View Post
    Acceleration is not a must in most cases.
    Right...
    Quote Originally Posted by selvaarchi View Post
    For moving a setallite from LEO to GEO or moving parts for a space construction, precision is more important than speed.
    Right, but for LEO to GEO it's hard for me to comment on. I don't know if the complexity of operations of a reusable tug would outweigh the simplicity of a fancy upper stage.
    You do have rendezvous to consider. Rockets are designed to not reach LEO. It's up to the upperstage and/or delivery system to get them to or past LEO.
    So; for the tug to take over, the craft would have to at least reach LEO, then provide for deorbit. That offset might make a simple orbit change craft to not have any advantage.

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    Quote Originally Posted by NEOWatcher View Post
    Right...

    Right, but for LEO to GEO it's hard for me to comment on. I don't know if the complexity of operations of a reusable tug would outweigh the simplicity of a fancy upper stage.
    You do have rendezvous to consider. Rockets are designed to not reach LEO. It's up to the upperstage and/or delivery system to get them to or past LEO.
    So; for the tug to take over, the craft would have to at least reach LEO, then provide for deorbit. That offset might make a simple orbit change craft to not have any advantage.
    My understanding was, if you could put 10 tons into GEO, the same rocket could deliver 20 tons to LEO. Think of the cost savings if we had an efficient space tug to do that.
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    Quote Originally Posted by selvaarchi View Post
    My understanding was, if you could put 10 tons into GEO, the same rocket could deliver 20 tons to LEO. Think of the cost savings if we had an efficient space tug to do that.
    Yes; but that's because of the fuel needed for the higher orbit.
    Going with the above ratios, you still need to get 8 tons of fuel into orbit or to the reusable craft somehow. There might not be an advantage one way or another. If your fuel delivery system is even one ton, and you have a ton of loss during the transfer and rendezvous, you break even.

    ETA.
    One more thing. You need more fuel to bring the tug back to LEO too.
    For GEO we just leave upper stages in a parking orbit where it's generally not a danger to debris like lower orbits have.
    Last edited by NEOWatcher; 2014-Jul-10 at 02:56 PM.

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    Quote Originally Posted by NEOWatcher View Post
    Yes; but that's because of the fuel needed for the higher orbit.
    Going with the above ratios, you still need to get 8 tons of fuel into orbit or to the reusable craft somehow. There might not be an advantage one way or another. If your fuel delivery system is even one ton, and you have a ton of loss during the transfer and rendezvous, you break even.
    That is why I wanted a space tug with an efficient engine. An ion engine or even using a solar sail will keep the fuel requirements low.
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    Quote Originally Posted by selvaarchi View Post
    That is why I wanted a space tug with an efficient engine. An ion engine or even using a solar sail will keep the fuel requirements low.
    Yes; that's why I mentioned that in that instance it's hard for me to comment on.

    Going by the current state of things (namely... working on chemical propulsion systems), we may not see that in some time, and the current systems aren't much of a prelude to such a system.

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    The Chinese have given the space tug a new name - "space shuttle bus,"

    http://www.wantchinatimes.com/news-s...20141109000072

    China's new upper stage aircraft for multistage rockets, dubbed the "space shuttle bus," will make its debut at the China International Aviation & Aerospace Exhibition in Zhuhai this week, reports the Chinese-language Beijing Morning Post.

    Developed by the Shanghai Academy of Spaceflight Technology of the China Aerospace Science and Technology Corporation, the main contractor for the Chinese space program, the upper stage aircraft will be attached to a carrier rocket and can be used to propel payload in space using its own power system after reaching an initial orbit.
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    Quote Originally Posted by selvaarchi View Post
    The Chinese have given the space tug a new name - "space shuttle bus,"
    I wonder if that's official. They don't even say "named", they say "dubbed". That's usually a term to refer to an unofficial term.
    Add to that; there's no Chinese translation along with it. Anything official from the Chinese, I am sure would be released first as the Chinese name.

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    Quote Originally Posted by NEOWatcher View Post
    I wonder if that's official. They don't even say "named", they say "dubbed". That's usually a term to refer to an unofficial term.
    Add to that; there's no Chinese translation along with it. Anything official from the Chinese, I am sure would be released first as the Chinese name.
    The answer is in the last but one paragraph of the article -

    The space shuttle bus, which some media outlets have reported will be known as the Yuanzheng-1 (Expedition-1),
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    Quote Originally Posted by NEOWatcher View Post
    Add to that; there's no Chinese translation along with it. Anything official from the Chinese, I am sure would be released first as the Chinese name.
    Well I'm sure it would, but it would be in hanzi, not roman letters. Does it really help an international audience to know how it's written in Chinese?
    As above, so below

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    Quote Originally Posted by selvaarchi View Post
    The answer is in the last but one paragraph of the article -
    The space shuttle bus, which some media outlets have reported will be known as the Yuanzheng-1 (Expedition-1),
    Then you are contradicting yourself.
    If its name is Yuanzheng (Expedition). then it is not named "space shuttle bus".

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    Quote Originally Posted by Jens View Post
    Well I'm sure it would, but it would be in hanzi, not roman letters. Does it really help an international audience to know how it's written in Chinese?
    So far, there has been a Chinese name (in roman characters) and translation for all their craft. Why would this be different?

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    Quote Originally Posted by NEOWatcher View Post
    So far, there has been a Chinese name (in roman characters) and translation for all their craft. Why would this be different?
    As with the latest luna probe their citizens are giving them nicknames.
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    Ah..OMV is the only thing deserving the name tug
    http://www.astronautix.com/craft/omv.htm

    That and the ATV
    http://www.esa.int/Our_Activities/Human_Spaceflight/ATV

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    Now there is another company proposing a space tug. The company is Lockheed Martin’s proposal to providing an affordable cargo resupply solution to NASA.

    http://www.lockheedmartin.com/us/ssc/crs2.html

    Our Commercial Resupply Service -2 (CRS-2) solution will fulfill NASA’s need for on time, affordable, and safe cargo transport to and from the International Space Station (ISS). Together, the Atlas V launch vehicle, Jupiter spacecraft, and Exoliner cargo carrier, will provide delivery and disposal of up to 6,500 kg cargo with each mission.

    Through the innovative repurposing of technology, Jupiter is a great example of Lockheed Martin’s commitment to providing an affordable cargo resupply solution, NASA’s deep space exploration goals and to the creation of commercial business opportunities. Jupiter helps enable the Journey to Mars by using an innovative container design as the foundation for future deep space habitats. The solution also opens up first of its kind commercial opportunities in space, including long-duration hosted payloads and in-orbit servicing missions. It does all of this while saving millions on each launch by avoiding the disposal of valuable avionics equipment after each mission
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    China has enhanced their first version of the space tug and given it the name Yuanzheng-1A. The new version can unload cargo 7 times compared to only one before. It's flight duration has gone up from 6.5 hours to 48 hours. Its main engine can start nine times and it can unload cargoes seven times, compared with the old model that unloads only once and starts its engine twice.

    http://news.xinhuanet.com/english/20..._135466077.htm

    Long March-7, China's new generation carrier rocket, has carried an upper stage aircraft into the space in its maiden flight Saturday, said a senior space program official.

    The upgraded model of Yuanzheng-1 (Expedition-1) is an independent aircraft carried by the carrier rocket with the ability of sending multiple spacecrafts into different orbits in space, said Wang Xiaojun, chief commander of the Long March-7 program, at a press conference after the Long March-7's successful launch.

    The aircraft, dubbed the "space shuttle bus", has been launched into the earth orbit by the Long March-7 and in the next 48 hours will deliver several "passengers" to different orbits using its own power system, Wang said.

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    Now Airbus gets into the space tug business.

    http://spacenews.com/airbus-to-chall...-tug-business/

    European manufacturer Airbus Defence and Space said Sept. 27 that it is creating a satellite-servicing vehicle capable of refueling, repairing, and monitoring the health of spacecraft orbiting Earth.

    In a tweet Sept. 27, the company described the Airbus Space Tug as “an autonomous spacecraft whose main missions are maintenance, logistics and the cleaning up of Space debris.”

    Airbus’ entrance into this market follows that of Orbital ATK, whose first Mission Extension Vehicle launches next year on an ILS Proton rocket, and Space Systems Loral, whose satellite servicer leverages work with the Pentagon’s Defense Advanced Research Projects Agency (DARPA). British-Israeli company Effective Space Solutions is also building servicer spacecraft based on small satellites.

    Airbus did not say when the Airbus Space Tug will launch, or if any customers have signed up to use the service.

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    China has come out the 4th version of the Yuanzheng (space tug)

    http://www.ecns.cn/2017/11-07/279866.shtml

    The Long March 2C, China's new generation of carrier rockets, will carry a new aircraft aloft in 2018 and an expert said it is of major significance for China's space development.

    The new aircraft, a Yuanzheng-1S, is able to carry different types of satellite into orbit. Its design work was finished in March, so it can be used for Sun-synchronous orbital missions next year, the China Academy of Launch Vehicle Technology (CALVT) said on its website.

    The Yuanzheng-1S is a simpler commercial version of the Yuanzheng-1 and is used for short missions and mid-to-low-Earth orbit, Wang Mingzhe, a research fellow from the Beijing Institute of Astronautical Systems Engineering said on the CALVT release.

    Yuanzheng-1, dubbed the "space shuttle bus," has been launched into the earth orbit by the Long March-7, Wang Xiaojun, chief commander of the Long March-7 program, told a press conference, the Xinhua News Agency reported in June 2016.

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    "A SPAC for space tugs will go public in 2021"

    https://qz.com/1915108/space-start-u...c-with-a-spac/

    Momentus has developed a water-fueled propulsion system and vehicle called Vigoride to provide that “last mile” transportation to satellites once they are launched into space on rockets. After test-flying a prototype in 2019, Momentus has lined up a partnership with SpaceX and signed contracts with small satellite operators, notably the internet-of-things play Swarm, to ferry their spacecraft to the right orbit.

    The company is effectively a middleman—its backers call it a space infrastructure company—that enables SpaceX and other rocket makers to provide more flexible service, while allowing satellite operators to spend more time and resources on their spacecraft’s payload than on figuring out how to get it where it’s going.
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    Spaceflight is one of several companies developing what you might call a tugboat for space—an “Orbital Transfer Vehicle,” or OTV. If these vehicles become common, satellite operators could spend less time and money on rocket engines for their satellites, and also realize cost reductions from by making shared flights more suitable for all kinds of spacecraft. Spaceflight’s OTV, called “Sherpa,” made an unpowered debut on this SpaceX rideshare mission. On similar missions planned later this year, the company intends to demonstrate a version equipped with thrusters.

    https://qz.com/1961141/spacexs-recor...space-tug-biz/
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    SpaceX / Inspiration4 Crew Dragon mission

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    Date: Q4, 2021
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    SpaceX_Inspiration4-patch.jpg

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    Woah!!!! This mission will have two people from Saint Judes Children’s Hospital, including a front line worker and a person from the general public!! This is going to be amazing. They’re going to fundraise $200 million to donate to the hospital. Wow. This incredible!

    https://twitter.com/Erdayastronaut/s...65733064830976
    Last edited by docmordrid; 2021-Feb-02 at 02:59 AM.

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    There was something called an Orbital Transfer Vehicle that had a wide aerobrake dish that was to be side-mount Shuttle-C style. A hammerhead atop an HLV might do-or OTRAG. That would be a nice tug.

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