Tag Archive: Extremis

Jan 10 2020

Operations Summary – Week of 1/6/20

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Jan 04 2019

Operations Summary – Week of 1/2/19

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Jun 22 2018

Operations Summary – Week of 6/18/18

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May 25 2018

Operations Summary – Week of 5/21/18

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May 22 2018

Extremis Phase Two Reconsiderations

Today mission planners for Extremis belatedly realized that their initial round of selection for Phase Two trajectories failed to take into account the fact that all trajectories were calculated from a starting equatorial 200km parking orbit. This was done for the sake of simplicity as the multi-flyby maneuver sequencer that ran various possibilities could easily eject the spacecraft from this orbit in any direction needed. In most cases for interplanetary travel the spacecraft will leave Kerbin at an inclined angle. Changing the inclination of an orbit is a very costly maneuver, especially when it is done deep in the gravity well close to the planet. Ideally, the spacecraft would be launched into an inclined orbit suitable from which to perform an escape burn with only a prograde component.

What this all means is there is a large segment of trajectories that have been overlooked for Phase Two because their v requirements appeared to exceed the 3km/s requirement when they did not actually need that much energy! Take, for example, a route that goes from Kerbin to Dres to Eve and then out to Urlum in the span of just over 5 years. The initial requirement for this trajectory was 3.513km/s of Δv, however looking at the departure burn requirement from Kerbin it defines a radial and normal burn component totaling 1.68km/s of Δv. If the spacecraft were launched into the properly-inclined orbit this portion of the burn could be almost entirely removed (this all depends on the capabilities of the launcher). Therefore the actual power requirements for this mission could be as low as 1.833km/s, which makes it feasible under the Phase Two considerations of  less than 3km/s Δv and less than 10 years of travel time.

The Extremis team will be going back and taking a closer look at trajectories with initial requirements of 3-5km/s to see how many drop below 3km/s when the radial/normal burn component is factored out. Those that remain and cover the gaps left by the one chosen mission will go through the Phase Two 500-iteration route stress test.

May 11 2018

Operations Summary – Week of 5/7/18

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May 10 2018

Extremis Phase Two Planning Extended

Phase Two began back at the end of February and calculations were completed last week to give mission planners 71 trajectories to review – 3 were found to be not feasible due to increasing the closest distance from the sun the spacecraft was allowed to travel. Unfortunately we made an error in the last report where we said the fly-bys that included Moho and Plock were in separate years – they are both in the 2020-2021 launch year. However this ended up not mattering since the fly-by that includes Moho would require an obscene 14.752km/s of delta-V to achieve, one of 14 trajectories that exceeded the 3km/s mission constraint after the new calculations. Of the options remaining, only one mission so far has been selected, which will launch in August of 2021 and perform a fly-by of Eve, Jool and Plock that will take just under 3 years at a cost of 2.6km/s of delta-V.

Mission planners will now return to calculating possible fly-by trajectories for 2019 and 2020 that exclude these three planets to see if we can find any other possible combinations under 3km/s of delta-V that have not yet been explored, like a route from Kerbin>Duna>Sarnus>Urlum/Neidon.

May 04 2018

Operations Summary – Week of 4/30/18

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Mar 30 2018

Operations Summary – Week of 3/26/18

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Mar 23 2018

Operations Summary – Week of 3/19/18

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