• Question: i have heard about the icesat2 and it has been improved by the icesat1 do you think that it can last for more than 10 years

    Asked by matematika to Phil on 8 Mar 2018.
    • Photo: Phil Allen

      Phil Allen answered on 8 Mar 2018:

      This wasn’t a mission I was familiar with so I’ve just done some reading on it.

      The life of spacecraft missions are often dictated by how long their propulsion system lasts. For missions in low earth orbit (such as ICESat-2 at 481 km altitude) this is to raise the orbital altitude back up when atmospheric drag starts to bring it down towards the earth. As a result the engineer in charge of designing the propulsion system will often provide more propellant than is needed in order to be 100% sure that there will be enough to last the mission.

      From the Orbital ATK website (who are making the propulsion system for ICESat-2) they state the mission life as 3 years and they are providing enough propellant for 7. So assuming the spacecraft is electrically functional for those 7 years it will be able to stay at the right altitude to operate as designed also.

      After the propellant is used up, atmospheric drag will start to slow the orbit down and it will eventually re-enter the Earth’s atmosphere. Assuming that this process takes longer than 3 years, the electronics on-board continue to function correctly and the payloads on-board can still operate with decreased orbital altitude then it should be able to last longer than ten years.

      However!

      There is an international agreement (which America and therefore NASA are part of) that state a satellite has to be re-entered if in low earth orbit within 25 years of the end of its mission. This is one way the space industry are trying to deal with space debris. In order to definitely achieve this some operators will use the last of their propellant to effectively aim at the ground while the satellite is still functioning. A satellite that is not responding to commands that is full of propellant could explode and this is obviously not desirable.

      So in short – yes I think it probably could last for 10 years but I think it will probably be commanded to de-orbit in 7 or 8 🙂

      Hope this helps and see the fact sheet on mainly the propulsion system is available here: https://www.orbitalatk.com/space-systems/science-national-security-satellites/science-environment-satellites/docs/ICESat-2_Factsheet.pdf

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