3 ms·
From the wiki[0]: > This required placing the probe into "hibernation" or safe mode to prolong its life beyond the original 4.5-year design. JAXA expressed som
by benten10 11y ago
From the wiki[0]:
> This required placing the probe into "hibernation" or safe mode to prolong its life beyond the original 4.5-year design. JAXA expressed some confidence in keeping the probe operational, pointing to reduced battery wear, since the probe was then orbiting the Sun instead of its intended Venusian orbit
>At a press conference on 10 December, officials reported that Akatsuki's engines fired for less than three minutes, far short of what was required to enter into Venus orbit
>Three peri-Venus orbital maneuvers were executed on 1 November,[11] 10 and 21 November 2011 using the RCS thrusters. A total delta-V of 243.8 m/s was imparted to the spacecraft. Because the RCS thrusters' specific impulse is low compared to the specific impulse of the OME, the previously planned insertion into low Venusian orbit became impossible. Instead, the new plan was to place the probe in a highly elliptical orbit with an apoapsis of a hundred thousand kilometers and a periapsis of a few thousand kilometers from Venus.
[0]: https://en.wikipedia.org/wiki/Akatsuki_(spacecraft)#Orbit_insertion_failure https://en.wikipedia.org/wiki/Akatsuki_(spacecraft)#Orbit_in...
- david-given 11y agoIt's worth emphasising that the OME (the main engine) and the RCS (the attitude thrusters) both run on hydrazine fuel, but the OME also has a separate tank of oxidant. So, the OME is a bipropellant engine, while the RCS is a monopropellant engine, which is why the OME is more efficient. (Aside: that's actually a really neat trick, and this is the first I've heard of it being used.) After the OME engine nozzle broke off and the engine became useless, the tank of oxidant became useless mass. (65kg.) So they dumped it overboard, simply venting it out the broken rocket nozzle. (Yes, the did point the vehicle in the right direction so that they could get some momentum change out of it.) Making that decision, to dump irreplaceable fuel overboard because of a conclusion you've reached by looking at some telemetry graphs, is one that I am very glad I wasn't the one to have to make.